The agricultural sector is responsible for 8% of South Africa's total exports (South African Department of Agriculture (DAFF), 2009). In the year 2008/2009, the largest agricultural export products for South Africa were wine (\$922 million); maize (\$904 million); citrus fruit (\$814 million); apples, pears, quinces (\$465 million) and grapes (\$316 million) (DAFF, 2010). During this period the largest export trade partners were Zimbabwe (\$698 million), the Netherlands (\$695 million), the United Kingdom (\$689 million), Kenya (\$367 million) and Mozambique (\$333 million) (DAFF, 2010). Due to favourable climatic conditions, a surplus of maize was produced in 2008/2009. Also, the recent national crisis in Zimbabwe led to increased maize export from South Africa to Zimbabwe. The trend in previous years has seen African trade increase with both Zimbabwe and Mozambique as major export destinations (DAFF, 2009; DAFF, 2010). Agricultural production and trade does vary naturally. However, wine and fruit exports consistently dominate as the major export products for South Africa.

The health risk posed by many pesticides was the driving force around the adoption of maximal residue levels (MRL) in agricultural products. MRLs have been initiated not only to ensure the quality of food imports, but also to ensure that the levels of pesticides that consumers are exposed to do not hold appreciable health risks. Of the 500 plus registered pesticides in South Africa, 229 have MRLs as listed in Table 1. Also listed in Table 1, are the chemical classifications of the pesticides as well the crops on which these pesticides are commonly used as related to the MRLs. The vast majority of these pesticides are carbamates, organophosphates and pyrethroid, that are additionally used on a wide variety of crops. There are also a number of alternative remedies registered for use in South African agricultural activities such as microbial, botanical and pheromone

In 2009, South Africa was ranked 31st on the international gross domestic product (GDP) list, making South Africa the top producing country from the African continent. The agroindustrial sector contributes approximately 12% to the GDP and employs 8% of the formal workforce. However, estimates have been as high as 30% when non-registered farm workers and subsistence farmers in rural areas were included. This entire sector is dependent on agricultural yields for their livelihood. To maintain agricultural yields a host of crop protection methods are implemented. One of the most effective and widely accepted methods is the use of pesticides. The agricultural sector is an essential part of the South African economy, and is vital for food security. According to the World Bank (2011), 70% of the world's poor rely on agriculture as their main source of income and employment. This trend is evident in South Africa as well. Smallholdings and subsistence farming are prevalent in rural areas where weather conditions permit, although current trends indicate an increased drive to develop these small-scale agricultural activities into commercial farms. However, without the necessary training and management this often leads to farming practices predominantly reliant on the use of pesticides. In the economic domain, pesticides do not only assist but also hinder sales, through export restrictions. There is a universal trend to increase pesticide legislation with more stringent adherence to MRLs in the global

The agricultural sector is responsible for 8% of South Africa's total exports (South African Department of Agriculture (DAFF), 2009). In the year 2008/2009, the largest agricultural export products for South Africa were wine (\$922 million); maize (\$904 million); citrus fruit (\$814 million); apples, pears, quinces (\$465 million) and grapes (\$316 million) (DAFF, 2010). During this period the largest export trade partners were Zimbabwe (\$698 million), the Netherlands (\$695 million), the United Kingdom (\$689 million), Kenya (\$367 million) and Mozambique (\$333 million) (DAFF, 2010). Due to favourable climatic conditions, a surplus of maize was produced in 2008/2009. Also, the recent national crisis in Zimbabwe led to increased maize export from South Africa to Zimbabwe. The trend in previous years has seen African trade increase with both Zimbabwe and Mozambique as major export destinations (DAFF, 2009; DAFF, 2010). Agricultural production and trade does vary naturally. However, wine and fruit exports consistently dominate as the major export

agents.

market.

products for South Africa.

**3. Agricultural activity in South Africa**

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 59

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Dicamba Benzoic acid herbicide 0.1 - 0.2: Maize, sorghum, sugar cane

Paraquat dichloride Bipyridylium herbicide 0.02 - 0.5: Cotton seed, maize, sugar

Iprovalicarb Carbamate fungicide 0.05 - 0.5: Grapes, potatoes and

hydrochloride Carbamate fungicide 0.5: Potatoes and 2: cucumbers Thiram Carbamate fungicide 3 - 5: Apples, apricots, grapes,

Carbosulfan Carbamate insecticide 0.05 - 0.2: Grapes and maize

Formetanate Carbamate insecticide 0.02 - 0.5: Apples, citrus, grapes and

Methiocarb Carbamate insecticide 0.1 - 0.2: Apples, apricots, citrus,

Bezimidazole precursor

benzoate Botanical insecticide 0.01: Tomatoes

Triflumuron Benzoyl urea insecticide

Diquat dibromide Bipyridylium desiccant

Pyrethrins Botanical insecticide

Gibberellins Botanical plant growth

Maneb Carbamate fungicide

Methomyl Carbamate insecticide

Oxycarboxin Carbamate fungicide 0.5: Beans

fungicide

and herbicide

Thiophanatemethyl

Emamectin,

Propamocarb

**associated crops**

pears

seed

cane

regulator 0.05- 0.2Apples, citrus and grapes

tomatoes

180: grapes

peaches

and wheat.

0.1 - 0.5: Chicken fat, citrus, litchis, mangoes and peaches; 2: Apples and

0.1: Barley, groundnuts and wheat; 3

0.05: Potatoes and 0.5: sunflower

1 - 2: Apples, apricots, beans, broccoli, Brussels sprouts, cabbage, cauliflower, cereal grains, citrus, cotton seed, cucurbits, dried fruit, dried nuts, dried vegetables, grapes, groundnuts, guavas, lettuce, oil seeds, peaches, plums, sunflower

0.01: all foodstuffs except cereal grains and grapes. 0.1: cereal grains.

peaches, pears and plums

grapes, pears and plums

0.02 - 0.2: Beans, broccoli, Brussels sprouts, cabbage, cauliflower, citrus, maize, peaches, potatoes, sorghum, sunflower seed, tomatoes and wheat

seed and tomatoes

**associated crops**

pears and peas

and mangoes

and wheat

wheat; 2 - 5: grapes

wheat; 2: Grapes

citrus and pears

apples and pears.

activator and fungicide 0.2 - 0.5: Tomatoes and mangoes

and apples; 1: Grapes

0.05: Avocadoes, litchis, nuts, mangoes, peaches and plums

0.05 - 0.1: Maize, groundnuts, pears, sugar cane and wheat. 1 - 3: Apples, apricots, avocados, bananas, grapes, peaches, pears, peppers, plums and tomatoes. 5: Citrus and mangoes.

0.01 - 0.1: Avocadoes, chicory, dry beans, groundnuts, mangoes, maize, oats and potatoes. 0.2 - 1: Grapes, peas and tomatoes. 3 - 5: Apples,

1 - 10: Apples, avocadoes, bananas, citrus, mushroom, musk melons, pears, pineapples and potatoes

canned peaches, pears and tomatoes

0.1 - 0.2: Barley, mushrooms, potatoes and wheat; 2- 10:

Avocadoes, bananas, citrus, ginger

0.05 - 0.5: Bananas, barley, grapes, groundnuts, maize, peaches, nuts

0.05 - 0.5: Apples, bananas, barley, cucurbits, mangoes, oats, peas and

0.02 - 0.1: Barley, beans, citrus, groundnuts, mangoes, oats, onions, potatoes, soya beans, tomatoes and

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Penconazole Azole fungicide 0.02 - 0.2: Apples, cucurbits, grapes,

Triadimenol Azole fungicide 0.05 - 0.5: cucurbits, peas, soya beans

Zoxamide Benzamide fungicide 0.05: Potatoes and 2: grapes

Novaluron Benzolurea herbicide 0.01 - 0.05: Apples, cotton seed,

Lufenuron Benzolurea insecticides 0.02 - 0.1: Tomatoes and cabbage

Diflubenzuron Benzoyl urea 0.01: Potatoes, 0.1: mushrooms, 1:

Benzothiadiazole plant

Flufenoxuron Benzoyl urea insecticide 0.05: Apples and pears Teflubenzuron Benzoyl urea insecticide 0.02 - 0.5: Citrus and litchis

Prochloraz Azole fungicide

Propiconazole Azole fungicide

Tebuconazole Azole fungicide

Triadimefon Azole fungicide

Paclobutrazol Azole plant growth

Benomyl Benzimidazole fungicide

Carbendazim Benzimidazole fungicide

Thiabendazole Benzimidazole fungicide

Acibenzolar-Smethyl

regulator

Tetraconazole Azole fungicide 0.5: Grapes

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 61

**Chemical Pesticide notes South African MRL (mg kg-1) and**

ester herbicide 0.05: Wheat

herbicide 0.05: Barley and wheat

growth regulator 0.1: Cotton seed

insecticide 1: Apples and pears

Diclofop-methyl Chlorophenoxy acid or

MCPA and its salts Chlorophenoxy acid or

Cycloxydim Cyclohexenone derivative herbicide

Tralkoxydim Cyclohexenone derivative

Iprodione Dicarboximide fungicide

Trifluralin Dinitroaniline herbicide

Dinocap Dinitrophenol derivative

Zineb Dithiocarbamate fungicide

Dimethipin Defoliant and plant

Tebufenozide Diacylhydrazine

Vinclozolin

ester herbicide

Triclopyr Chloropyridinyl herbicide 0.1: Citrus

Dicarboximide nonsystemic general use pesticide and fungicide

Pendimethalin Dinitroaniline herbicide 0.05: Potatoes

fungicide and insecticide

Oxyfluorfen Diphenyl ether herbicide 0.05: Citrus and garlic

Fomesafen Diphenyl ether herbicide 0.05: Dry beans, groundnuts and

Furfural Fumigant Carrots, lettuce, onions, potatoes

**associated crops**

0.1: Barley, maize, potatoes, rye, sorghum, sugar cane and wheat

soya beans and tomatoes.

0.5: Beans, cottonseed, cucurbits, dry beans, grapes, groundnuts, onions,

0.05 - 0.5: ginger, onions and canned peaches; 1 - 5: Apricots, apples, citrus, grapes, kiwifruit, peaches, pears, plums, raspberries, strawberries and tomatoes

1 - 3: Strawberries and grapes

tomatoes; 1: Carrots

soya beans

and sugar cane

 0.05: Cabbage, chillies, cowpeas, dry beans, groundnuts, kidney beans, soya beans, sunflower seeds and

1: Apples, broccoli, Brussels sprouts, cabbage, cauliflowers, cucurbits, grapes, peaches, pears and peas

0.05 - 0.5: Groundnuts, onions and potatoes; 3: Apples, apricots, bananas, beans, boysenberries, broccoli, Brussels sprouts, cabbage, cauliflower, citrus, cucurbits, grapes, guavas, mangoes, olives, papayas, peaches, pears, peppers, plums, quinces, tomatoes and youngberries

**associated crops**

and wheat

0.05 - 0.5: Apples, broccoli, Brussels sprouts, cabbage, cauliflower, citrus, cotton seed, groundnuts, oats, peaches, nuts, potatoes, sorghum

0.05 - 0.5: Broccoli, Brussels sprouts, cabbage, cauliflower, cotton seed, maize, potatoes, sorghum, sugar cane, sunflower seed and wheat.

0.1 - 0.5: Cactus pears, castor oil seed, cottonseed, maize, meat, eggs, milk and poultry. 2.5: Apples, apricots, beans, grapes, pears,

0.05: cottonseed, nuts, maize and pineapples. 0.2-0.5: Bananas, citrus, coffee, grapes, groundnuts, sweet potatoes and tomatoes. 1 -2: Fodder (hay), potatoes and hops (dry).

Beans, maize, potatoes, sugar cane, sunflower seed, sweet corn and

Pineapples, potatoes and tomatoes.

0.05 - 0.1: Broccoli, Brussels sprouts, cabbage, groundnuts, maize, pineapples, potatoes, soya beans, sugar cane and sunflower seed

0.02- 0.05: Cotton seed, groundnuts, maize, sorghum and sugar cane

0.05: Beans, cotton seed, dry beans, groundnuts, maize, potatoes, sorghum, soya beans, sugar cane

0.05 - 0.1: Cabbage, dry beans, groundnuts, maize, potatoes, sugar cane, sunflower seed and sweet corn

and sunflower seed

herbicide 0.1 - 0.2: Maize, onions and sorghum

sorghum and wheat

sweet potatoes

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Thiodicarb Carbamate insecticide 0.1 - 0.5 Cotton seed and maize

Bendiocarb Carbamate pesticide 0.1 - 0.2: Maize and sorghum

Pirimicarb Carbamate insecticide

Carbofuran Carbamate insecticide and nematicide

Aldicarb Carbamate pesticide

EPTC Carbamate pesticide

Alachlor Chloroacetanilide

Acetochlor Chloroacetanilide

Metazachlor Chloroacetanilide

Metolachlor Chloroacetanilide

Propachlor Chloroacetanilide

Carbaryl

Dichlorophene

Propoxur Carbamate insecticide 0.05: grapes

Carbamate insecticide, nematicide and plant growth regulator

Chlorinated phenol fungicide, herbicide,

microbiocide

herbicide

herbicide

herbicide

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 63

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Inorganic fungicide, herbicide, antimicrobial and pH adjuster

Inorganic heavy metal herbicide, insecticide and

Inorganic phosphide

antimicrobial and

Inorganic -zink carbamate

Buprofezin Insect growth regulator 0.05: Avocadoes and peaches Bromopropylate Insecticide 0.2 - 3: Bananas, citrus, cotton seed

Etoxazole Insecticide 0.1 - 0.2: Apples, pears and tomatoes Fenazaquin Insecticide 0.05 - 0.5: Apples, citrus, pears and

Triforine Insecticide and fungicide 0.1 - 0.5: Cucurbits and peas; 1 - 2:

Spirodiclofen Keto-enol insecticide 0.01: Peaches

rodenticide

insecticide

fumigant

fungicide

Mancozeb Inorganic-zinc carbamate fungicide

Metiram Inorganic-zinc carbamate fungicide

Sulphur Inorganic herbicide and

Phosphoric acid

Calcium arsenate

Aluminum phosphide

Propineb

Indoxacarb, S-

isomer Insecticide

Propargite Insecticide

Tetradifon Insecticide

**associated crops**

0.2: Citrus

litchis peel

180: grapes

youngberries

180: grapes

and tomatoes

and grapes

tomatoes

25 - 50: Grapes and citrus

50 - 55: Apples, apricots, avocadoes, bananas, beans, boysenberries, citrus, cucurbits, grapes, litchis (pulp), mangoes, papaya, peaches, pears, peas, peppers, plums, tomatoes and youngberries; 1 000:

0.01: all foodstuffs except cereal grains and grapes. 0.1: cereal grains.

0.5: Groundnuts and potatoes; 3: Boysenberries, grapes, tomatoes and

0.01: all foodstuffs except cereal grains and grapes. 0.1: cereal grains.

0.5: Potatoes; 3: Apples, apricots, beans, grapes, peaches, pears, plums

0.01 - 0.05: Potatoes, cauliflower; 0.02 -0.2: Tomatoes, beans, peaches and peas; 1: Apples, cabbage, broccoli, Brussels sprouts and pears

0.05 - 0.5: Cotton seed and pears; 2 -

3: Apples, citrus, peaches, strawberries and tomatoes

pears, plums and dry tea

0.05: Cotton seed; 5 - 8: Apples, apricots, citrus, cotton seed, peaches,

Apples, beans, peaches and plums

**associated crops**

5 - 50: Avocadoes, boysenberries,

10- 100: Cereal grains, dried fruit, dried legumes, processed grain products and groundnuts

2: Apples, citrus, peaches, pears, plums and tomatoes. 150: Hops

0.2 - 2: Apples, beans, citrus, peaches, pears, peppers and

0.5 - 2: Barley, citrus, maize, potatoes, rye, sorghum, sugar cane

0.02 - 0.05: Apples, carrots, grapes, nectarines, pears, plums, potatoes

0.1: Barley, maize, oats, sorghum,

0.01: all foodstuffs except cereal grains and grapes. 0.1: cereal grains.

citrus, cucumber, grapes, pineapples, potatoes and

tomatoes

and plums

youngberries

1: grapes

(dry).

tomatoes

and wheat

and sunflower seed

sugar cane and wheat

soya beans

180: grapes

microbiocide 1: Apples, pears and quinces

grapes

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Dithianon Fungicide 2: Apples, apricots, peaches, pears

Famoxadone Fungicide 0.01 - 0.02: Potatoes, 0.2: tomatoes, 1:

Spiroxamine Fungicide 0.05: Barley and wheat; 0.1: peas and

Cymoxanil Fungicide 0.01 - 0.2: Grapes, potatoes and

Epoxiconazole Fungicide 0.01 - < 0.05: Maize and barley

Guazatine Fungicide 2.5: Tomatoes and 5: Citrus

Fludioxonil Fungicide 0.5: Grapes

Halogenated organic fumigant, herbicide, insecticide and nematicide

Fosetyl-Al Fungicide

Methyl bromide

Magnesium phosphide

Dodine Guanidine fungicide and

Cyhexatin Heavy metal, organotin

Fenbutatin-oxide Heavy metal, organotin

Ioxynil Hydroxybenzonitrile

Bromoxynil phenol Hydroxybenzonitrile

insecticide

rodenticide

2,4-D Herbicide

Fluorochloridone Herbicide

insecticide

insecticide

Mesotrione Herbicide 0.01: Maize

Inorganic fumigant and

Sulcotrione Herbicide 0.05: Maize and sugar cane

herbicide 0.05: Sugar cane

Imazapyr Imidazolinone herbicide 0.05: Dry beans, groundnuts and

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 65

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Endosulfan Organochlorine insecticide

Lindane Organochlorine insecticide

Fenthion Organophosphate acvicide

Acephate Organophosphate

Azinphos-methyl Organophosphate

Cadusafos Organophosphate

Chlorpyrifosmethyl

Malathion / Mercaptothion and rodenticide

and insecticide

insecticide

insecticide

insecticide

Organophosphate

Organophosphate

insecticide

**associated crops**

20: Hops (dry)

quinces.

plums.

potatoes

insecticide 8: Cereal grains

0.05: Granadillas, nuts, pineapples and potatoes; 0.1 - 1: Apples, apricots, Boysenberries, broccoli, Brussels sprouts, cabbage,

cauliflower, cherries, citrus, coffee, cotton seed, cucurbits, grapes, groundnuts, maize, onions, paprika, peaches, pears, peas, plums, quinces, sorghum, sugar cane, sunflower, tomatoes, wheat and youngberries;

0.01 - 0.02: Milk, cottonseed, onions, potatoes and sweet potatoes; 1: Apples, apricots, beans, broccoli, Brussels sprouts, cabbage,

cauliflower, peaches, pears, plums.

0.1 - 1: Apples, apricots, coffee, cucurbits, grapes, guavas, kiwifruit, mangoes, peaches, pears, plums and

1 - 3: Apples, broccoli, Brussels sprouts, cabbage, cauliflower, grapes, peaches, pears, plums,

potatoes and tomatoes

0.05: Cottonseed, olives and

0.02 - 0.05: Bananas, citrus and

0.05: maize, peas, onions, sorghum and sugar cane; 1 - 8: Apples

apricots, avocadoes, bananas, beans, broccoli, Brussels sprouts, cabbage, cauliflower, cereal grains, citrus clover, cotton seed, cucurbits, dried fruits, dried nuts, granadillas, grapes, groundnuts, guavas, litchis, mangoes, mushrooms, oil seeds, papayas, peaches, pears, peppers, pineapples, plums, quinces, sunflower seed and tomatoes

potatoes. 0.04: Apples and pears. 0.1 - 0.2: Apricots, citrus, peaches and

**associated crops**

0.05 - 0.2: Bananas, maize, pineapples and sugar cane

0.01 - 0.5: Apples, apricots, beans, citrus, cabbage, cucurbits, grapes, guavas, mangoes, olives, peaches, pears, peas,

1: Potatoes and nuts. 20: Apples, apricots, avocados, beans, boysenberries, broccoli, Brussels sprouts, cabbage, cauliflower, celery, cherries, citrus, coffee, cucurbits, granadillas, grapes, guavas, lettuce, mangoes, olives, peaches,

cotton seed, tomatoes and wheat

Apples, apricots, bananas, beans, broccoli, Brussels sprouts,

peaches, pears, peas,

peppers, plums, quinces and

cabbage, cauliflower, cherries, citrus, cotton seed, cucurbits, granadillas,

0.05 - 0.5: Apples, citrus, cotton seed, cucurbits, grapes, maize, sorghum, sunflower seed, tomatoes and

plums, potatoes and

pears, peppers, plums, strawberries, tomatoes and

youngberries.

wheat

and fungicide 0.02 - 0.05: Apples and cotton seed

cabbage

tomatoes.

tomatoes

grapes

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Dimethomorph Morpholine fungicide 0.01: Potatoes, 0.1: tomatoes and 5:

Acetamiprid Neonicotinoid insecticide 0.2 - 0.50: Barley, canola, citrus, oats,

Thiacloprid Neonicotinoid insecticide 0.1: Peaches and 1: apples

monohydrochloride Nereistoxin insecticide 5: Onions, 10: tomatoes and 150:

and herbicide 0.05: Sugar cane

Tridemorph Morpholine fungicide 0.1 - 0.2: Cucurbits and peas

Milbemectin Microbial insecticide 0.01: Apples and tomatoes

Ametryne Methylthiotriazine

Spinosad Microbial insecticide

Copper and its salts Multiple forms and uses

Imidacloprid Neonicotinoid insecticide

Thiamethoxam Neonicotinoid insecticide

MSMA Organoarsenic defoliant

Dicofol Organochlorine insecticide

Cartap

herbicide

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 67

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Organophosphate

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide

Diazinon Organophosphate

Dimethoate Organophosphate

Methamidophos Organophosphate

Methidathion Organophosphate

Mevinphos Organophosphate

Omethoate Organophosphate

Phosmet Organophosphate

Profenofos Organophosphate

Demeton-S-methyl

(mixture)†

**associated crops**

wheat

wheat

plums

2: Citrus

insecticide 2 - 5: Apples and pears

0.1 - 0.5: Apples, apricots, barley, beans, broccoli, Brussels sprouts, cabbage, cauliflower, citrus, cotton seed, eggplant, groundnuts, maize, olives, onions, peaches, pears, peas,

0.02: Milk, 0.2 - 0.7: apples, apricots, beans, broccoli, brussels sprouts, cabbage, meat, cauliflower, mushrooms, peaches, pears, pineapples, plums and tomatoes

Apples, barley, beans, broccoli, brussels sprouts, cabbage, cauliflower, citrus, cotton seed, cucurbits, grapes, groundnuts, peaches, pears, pineapples, plums, potatoes, sorghum, strawberries and

0.05 - 0.5: Canola, citrus, potatoes and tomatoes; 1: Apples, apricots, broccoli, brussels sprouts, cabbage, mangoes, peaches, pears and

0.02 - 0.3: Apples, apricots, cactus pears, cherries, grapes, peaches, pears, plums and potatoes;

0.05: Potatoes; 0.1 - 0.2: Beans, broccoli, brussels sprouts, cabbage, cauliflower, citrus, cucurbits, grapes, lettuce, peas, peppers, spinach,

0.05 - 0.5: Barley, cotton seed, oats and onions; 1 - 1.5: Apples, grapes,

0.05: Onions and potatoes; 0.5 - 1: Brussels sprouts, cabbage, cauliflower, citrus and tomatoes

tomatoes and wheat

pears, peas and wheat

peppers, plums, potatoes, Rooibos, sorghum ,tomatoes and

**associated crops**

wheat.

and wheat

citrus

insecticide 0.2: Cereal grains and groundnuts

sunflower seed

tomatoes

tomatoes

0.1 - 0.4: Apples, apricots, beans, broccoli, Brussels sprouts, cabbage, cauliflower, citrus, cotton seed, cucurbits, aubergine, groundnuts, maize, onions, peaches, pears, peas,

0.05 - 0.5: Barley, beans, beetroot, broccoli, Brussels sprouts, cabbage, cactus pears, carrots, castor-oil seed, cauliflower, citrus, coffee, cotton seed, cucurbits, aubergine,

groundnuts, mangoes, onions, peas, peppers, quinces, sorghum, spinach, sweet potatoes, tomatoes, turnips

3 - 10: Groundnuts, maize, sorghum, soya beans, stored wheat and

0.05 - 0.5: Citrus, groundnuts, pears

0.05 - 0.2: Apples, apricots, broccoli,

cauliflower, citrus, coffee, cucurbits, granadillas, grapes, guavas, litchis, maize, peaches, plums, quinces and sweet potatoes; 1: Beans and

and potatoes; 1 - 10: Beans, grapes, peaches, plums and

0.05: Apples, apricots, citrus, mangoes, pears and plums; 1:

Brussels sprouts, cabbage,

Grapes and guavas

0.1 - 0.2: Mangoes, onions and potatoes; 1: Broccoli, Brussels sprouts, cabbage, cauliflower and

peppers, plums, potatoes, Rooibos, sorghum, tomatoes and

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Organophosphate

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide

insecticide 1: Citrus

Parathion Organophosphate

Phenthoate Organophosphate

Phoxim Organophosphate

Pirimiphos-methyl Organophosphate

Procymidone Organophosphate

Prothiofos Organophosphate

Temephos Organophosphate

Trichlorfon Organophosphate

Oxydemetonmethyl

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 69

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Bioresmethrin Pyrethroid insecticide

Cyfluthrin Pyrethroid insecticide

Cyfluthrin, beta Pyrethroid insecticide

gamma Pyrethroid insecticide

Cyhalothrin, lamba Pyrethroid insecticide

Cypermethrin Pyrethroid insecticide

alpha Pyrethroid insecticide

Cypermethrin, beta Pyrethroid insecticide

Cyhalothrin,

Cypermethrin,

**associated crops**

plums.

1: Wheat

wheat.

wheat.

wheat and nuts

0.05: Groundnuts. 0.1 - 1: Apples, apricots, beans, peaches, pears and

0.05: Cottonseed. 0.1 - 0.2: Apples, beans, broccoli, Brussels sprouts, cabbage, cauliflower, grapes, maize, pears, peas, sorghum and tomatoes.

0.05 - 0.2: Apples, beans, broccoli, Brussels sprouts, cabbage, canola, cauliflower, cotton seed, grapes, nuts, maize, peaches, pears, peas, potatoes, sorghum, tomatoes and

0.01 - 0.5: Apples, apricots, grapes, beans, cotton seed, cruciferae, groundnuts, nuts, maize, onions, peaches, pears, peas, plums, potatoes, sorghum, tomatoes and

0.01 - 0.5: Apples, apricots, beans, broccoli, Brussels sprouts, cabbage, cauliflower, grapes, groundnuts, maize, onions, peaches, pears, peas, plums, potatoes, sorghum, tomatoes,

0.05 - 0.1: Beans, broccoli, Brussels sprouts, cabbage, cauliflower, cottonseed, grapes, groundnuts, nuts, peas and plums. 0.2 - 1: Apples, citrus, maize, peaches, pears, green Rooibos tea, tomatoes and wheat. 2: Dried rooibos tea

0.02-0.05: groundnuts, cotton seed, grapes, nuts, potatoes, sugar cane and wheat. 0.1 - 0.5: Beans, broccoli,

cauliflower, maize, peaches, pears,

0.05 - 0.5: Apples, beans, citrus, cruciferae, grapes, groundnuts, nuts, maize, peaches, pears, peas, plums, sorghum, tomatoes and wheat.

Brussels sprout, cabbage,

peas and tomatoes

**associated crops**

tomatoes.

insecticide and nematicide 0.01: Potatoes and 0.05: citrus

insecticide and nematicide 0.05: Coffee and 1: citrus

wheat

potatoes

and wheat

and tomatoes.

herbicide 0.5: Sugar cane and 2: Maize

Plant growth regulator 1: Apples and pears

Fipronil Pyrazole insecticide 0.01 - 0.05Broccoli, cabbage,

Pyraflufen-ethyl Pyrazolylphenyl herbicide 0.01: Barley and wheat

0.05 - 1: Apples, apricots, bananas, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, citrus, grapes, lettuce, mangoes, maize, wheat, peaches, pears, plums, potatoes and

0.05 - 0.5: Cabbage, cauliflower, coffee, cotton seed, onions, potatoes,

0.01 - 0.2: Bananas, citrus, cotton seed, ginger, grapes, groundnuts, guavas, litchis, onions, papaya, peaches, peas, nuts, pineapples,

0.05: Apples, broccoli, Brussels sprouts, cabbage, cauliflower, cotton seed, maize, onions, potatoes and

0.05 - 0.1: Citrus, dry beans, groundnuts, maize, potatoes, sorghum and sunflower seed

0.05- 0.1: Bananas, citrus and

0.05: Maize and sugar cane. 1 - 5: Apples, cherries, citrus, cotton seed, grapes, peaches, pineapples, plums

 0.01 - 0.5: Apples, citrus, grapes, nectarines, pears, plums, potatoes

cauliflower, citrus and mangoes

tomatoes and wheat

potatoes and tomatoes

**Chemical Pesticide notes South African MRL (mg kg-1) and**

insecticide and nematicide

insecticide and nematicide

insecticide and nematicide

insecticide and nematicide

insecticide and nematicide

Chlorpyrifos Organophosphate

Disulfoton Organophosphate

Ethoprop Organophosphate

Fenamiphos Organophosphate

Methyl parathion Organophosphate

Phorate Organophosphate

Terbufos Organophosphate

Fosthiazate Organophosphate

Ortho-

salts

1-

Glyphosate and its

Naphthaleneacetic acid, methyl ester

Ethephon Organophosphate plant

Chlorfenapyr Pyrazole insecticide

nematicide

growth regulator

phenylphenol Phenol antimicrobial 10: Citrus

Phosphonoglycine

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 71

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Kresoxim-methyl Strobin Fungicide 0.01 - 0.5: Apples, citrus, cucurbits,

Trifloxystrobin Strobin fungicide 0.05 - 0.5: Apples, citrus, cucurbits,

Clofentezine Terazine insecticide 0.05- 0.2: Apples, pears and tomatoes

Simazine Triazine herbicide 0.2: Apples, grapes, maize and pears;

Atrazine Triazine herbicide 0.05: Maize, sorghum and sugar cane

Prometryn Triazine herbicide 0.05: Cottonseed and 0.5: carrots Terbutryn Triazine herbicide 0.05: Groundnuts and peas

Folpet Thiophtalimide fungicide 0.5: Tomatoes; 15: grapes

insecticide and acaricide

Pyraclostrobin Strobin Fungicide 0.1 - 0.5: Citrus and grapes

Chlorsulfuron Sulfonylurea herbicide 0.05: Oats and wheat

methyl, sodium salt Sulfonylurea herbicide 0.05: Barley and wheat

methyl Sulfonylurea herbicide 0.05: Barley and wheat

methyl Sulfonylurea herbicide 0.05: Barley and wheat Triasulfuron Sulfonylurea herbicide 0.05: Barley and wheat Tribenuron methyl Sulfonylurea herbicide 0.05: Barley and wheat

Nicosulfuron Sulfonylurea herbicide 0.05: Maize

Azoxystrobin Strobin fungicide

Iodosulfuron

Metsulfuron-

Thifensulfuron-

Piperonyl butoxide Synergist

Captan Thiophtalimide

Amitraz Triazapentadien

Cyanazine Triazine herbicide

**associated crops**

and tomatoes.

grapes, mangoes and pears

grapes, maize, pears and potatoes

5 - 20: Apples, apricots, beans, broccoli, Brussels sprouts, cabbage, cauliflower, cereal grains, citrus, cotton seed, cucurbits, dried fruit, dried nuts, dried vegetables, grapes, groundnuts, guavas, lettuce, oil seeds, peaches, pears, plums, sunflower seed and tomatoes

15: Apples, apricots, boysenberries, celery, grapes, guavas, olives, peaches, pears, plums, quinces, spinach, strawberries, tomatoes and

0.2 - 0.5: Apples, citrus, cotton seed,

0.05: Cottonseed, maize, sugar cane and sweet corn. 0.1 -1: Peas and

youngberries.

10: Asparagus

tomatoes

rooibos

0.01 - 0.05: Brussels sprouts, cabbage, maize and potatoes. 0.2 - 1: Broccoli, cauliflower, citrus, grapes, mangoes

**associated crops**

and wheat.

hops (dry)

wheat

Bifenthrin Pyrethroid insecticide 0.05 - 0.2: Apples, cottonseed, maize,

Fluroxypyr Pyridinecarboxylic acid 0.1 - 0.5: Fat, meat, milk and kidney

Cyprodinil Pyrimidine fungicide 0.05 - 0.1: Apples, barley and grapes

plant growth regulator 1: Cotton seed

Bupirimate Pyrimidine fungicide 0.05 - 0.5: Apples, cucurbits,

Quinoxyfen Quinoline fungicide 0.5 - 1: Cucurbits and grapes

Fenarimol Pyrimidine fungicide 0.2: Apples and grapes

0.05 - 0.5: Apples, beans, broccoli,

0.05: Cactus pears, groundnuts, mangoes, onions, potatoes, sweet potatoes and tomatoes. 0.1 - 0.2: Apples, beans, broccoli, Brussels sprouts, cabbage, cauliflower, cotton seed, grapes, lettuce, maize, paprika, peaches, pears, plums, sorghum. 1 - 5: Hops (dry), oats, rye, stored grain

0.05 - 0.5: Apples, beans, cotton seed, grapes, mangoes, maize, pears, peas, potatoes, sorghum, sunflower seed, tomatoes and wheat, 15: hops (dry).

0.05 - 0.1: Grapes, mangoes, wheat, peas, potatoes, tomatoes; 0.5 -1: apples, beans, cotton seed, maize, pears, sorghum, sunflower seed; 15:

0.05 - 0.5: Apples, beans, cotton seed, grapes, groundnuts, maize, pears, peas, potatoes, sorghum, soya beans and tomatoes; 2: Cereal grains

0.05 - 0.2: Apples, canola, cotton seed, peaches, pears, tomatoes and

pears, potatoes and tomatoes.

hops with MRL of 10

mangoes and peaches

0.1: Apples, pears, tomatoes and

Brussels sprouts, cabbage, cauliflower, cotton seed, grapes, nuts, maize, peaches, pears, peas, sorghum, tomatoes and wheat.

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Cypermethrin, zeta Pyrethroid insecticide

Deltamethrin Pyrethroid insecticide

Esfenvalerate Pyrethroid insecticide

Fenvalerate Pyrethroid insecticide

Permethrin Pyrethroid insecticide

Tau-fluvalinate Pyrethroid insecticide

Acrinathrin Pyrethroid insecticide and acaricide

Mepiquat chloride Quatenary ammonium

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 73

pesticide use or incorrect measurements), South Africa would have lost an estimated income of \$ 54 million through trade (assuming a typical minimum four month period that is required to take corrective action and have the citrus trade re-instated). To avoid such losses, South Africa is obliged to meet export requirements in primarily two ways, namely through the responsible and correct use of pesticides and through the accurate, internationally recognised measurement and monitoring of pesticide residues (Frohberg et al., 2006; DAFF, 2009, 2010). The European Commission's (EC) Rapid Alert System for Food and Feed (RASFF) identifies risks in food and feed imported into the EU (EU, 2011). Depending on the risk level, the EC will either prohibit the consignment from entering the country (border rejection) or send out an alert notification or an information notification. The former requires immediate corrective action, i.e., withdraw/recall of the product, while the latter requires precautions to be taken in future to avoid further notifications (EU, 2011, 2009). Since 2000, South Africa has received only 4 information notifications and one alert notification for pesticide residues detected on fruit. The detected pesticides were omethoate, dimethoate and ethephon in grapes; methomyl in pears and prophenophos in peppers. The majority of South African border rejections and notifications are due to MRLs being exceeded for aflatoxins in groundnuts. In general the mycotoxin hazard category tends to dominate as the main cause for border rejection in the

In accordance with Article 12 of EU Regulation 882/2004 (EU, 2004), laboratories designated for official control of pesticide residues within the EU must be accredited to ISO/IEC 17025. Accreditation of laboratories is seen as the most effective way of defeating non-tariff technical barriers to trade (for example, eliminating doubt on the quality of test results from exporting countries). For export purposes, measurements performed by analytical laboratories who are accredited to ISO 17025, are internationally accepted, in terms of the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement (ILAC MRA) for trade, of which South Africa is a signatory since November 2000 (ILAC), 2001). Although there are several laboratories analysing pesticide residues in South Africa (National Laboratory Association (NLA), 2010), according to the South African National Accreditation System (SANAS), (SANAS, 2010), there are only nine ISO 17025 accredited analytical laboratories in South Africa capable of analysing pesticide residues in food and feed. Of these laboratories, two are able to analyse the raw and finished products of pesticide formulations (SANAS, 2010). There are two government entities responsible for pesticide residue measurements in food and plant products in South Africa, namely the Department of Agriculture, Forestry and Fisheries and the Department of Health (DoH). Fresh produce for export is well monitored by the Perishable Products Export Control Board (PPECB). The PPECB is South Africa's official certification agency for the export of perishable products. It is mandated by the Department of Agriculture to deliver cold chain services in terms of the PPECB Act, No.9 of 1983 and delivers inspection and food safety services, under the APS Act, No.119 of 1990. The PPECB is also responsible for monitoring imported consignments of fresh produce. The PPECB is ISO 17025 accredited for the analysis of mycotoxins in various plant products (PPECB, 2011). The DoH Food Control Directorate has inspectors that regularly sample food items from the local trade industry; the analysis of which is outsourced to private accredited laboratories with the capacity to

EU across all importers (EU, 2011, 2009).

conduct extensive analyses.

Table 1. Pesticides registered in South Africa, including information on chemical classification, application use and relevant crops as indicated by South African MRL levels (South African Department of Health (DOH), 2005; PAN, 2010).

The main agricultural exports in 2009/2010 were wine (\$846 million), citrus fruit (\$797 million), grapes (\$495 million), apples, pears and quinces (\$435 million) and cane sugar (\$377 million) (DAFF, 2010). During 2009/10, the Netherlands, the United Kingdom, Zimbabwe, Mozambique and Germany were the five largest trading partners. Approximately 20.7% of South Africa's total agricultural exports for the period July 2009 to June 2010 went to the Netherlands and the United Kingdom (DAFF, 2010). These are all crops requiring the responsible use of pesticides (including fungicides and herbicides). The EU, U.S.A and Japan, have stringent food safety requirements as compared to African countries that typically adhere to FAO/WHO CODEX Alimentarius recommendations. To ensure continued trade, South African exporters must continuously ensure that their export products may meet the EU food safety standards in addition to private standards set by large food retailers, e.g., Tesco, Marks & Spencer, Sainsbury's in the U.K (Urquhart, 1999; Frohberg, 2006; String Communication, 2007).

The financial impacts of providing fresh produce that meet the requirements of the importing country are significant. For example: should South Africa be suspended from trading citrus fruit due to exceeding an EU pesticide MRL (either through incorrect

**associated crops**

0.05: Maize, peas and sorghum

mushrooms and 5: green beans

0.05 - 0.5: Avocados, broccoli, Brussels sprouts, cabbage, cauliflower, pineapples, potatoes and tomatoes. 1 - 1.5: Boysenberries, citrus, grapes and youngberries

**Chemical Pesticide notes South African MRL (mg kg-1) and**

Cyromazine Triazine insecticides 0.05: Potatoes, 0.5: tomatoes, 2:

Metribuzin Triazinone herbicide 0.05: Asparagus and soya beans

herbicide 0.01: Wheat

herbicide 0.05: Wheat

regulator 0.5: Cotton seed

Diuron Urea herbicide 0.05 - 0.1: Asparagus and sugar cane Benalaxyl Xylylalanine fungicide 0.05: Potatoes and tomatoes. 2:

Table 1. Pesticides registered in South Africa, including information on chemical

classification, application use and relevant crops as indicated by South African MRL levels

The main agricultural exports in 2009/2010 were wine (\$846 million), citrus fruit (\$797 million), grapes (\$495 million), apples, pears and quinces (\$435 million) and cane sugar (\$377 million) (DAFF, 2010). During 2009/10, the Netherlands, the United Kingdom, Zimbabwe, Mozambique and Germany were the five largest trading partners. Approximately 20.7% of South Africa's total agricultural exports for the period July 2009 to June 2010 went to the Netherlands and the United Kingdom (DAFF, 2010). These are all crops requiring the responsible use of pesticides (including fungicides and herbicides). The EU, U.S.A and Japan, have stringent food safety requirements as compared to African countries that typically adhere to FAO/WHO CODEX Alimentarius recommendations. To ensure continued trade, South African exporters must continuously ensure that their export products may meet the EU food safety standards in addition to private standards set by large food retailers, e.g., Tesco, Marks & Spencer, Sainsbury's in the U.K (Urquhart, 1999; Frohberg, 2006; String Communication,

The financial impacts of providing fresh produce that meet the requirements of the importing country are significant. For example: should South Africa be suspended from trading citrus fruit due to exceeding an EU pesticide MRL (either through incorrect

Grapes

Pymetrozine Triazine insecticides 0.02 - 0.05: Cabbage and cotton seed

Triazine herbicide, antimicrobial and

Hexazinone Triazinone herbicide 1: Pineapples

Sulfentrazone Triazolone herbicide 0: Sugar cane

Terbacil Uracil herbicide 1: Peaches

Pencycuron Urea fungicide 0.05: Potatoes

(South African Department of Health (DOH), 2005; PAN, 2010).

algaecide

Florasulam Triazolopyrimidine

Flumetsulam Triazolopyrimidine

Thidiazuron Urea defoliant and plant

Metalaxyl Xylylalanine fungicide

Terbuthylazine

2007).

pesticide use or incorrect measurements), South Africa would have lost an estimated income of \$ 54 million through trade (assuming a typical minimum four month period that is required to take corrective action and have the citrus trade re-instated). To avoid such losses, South Africa is obliged to meet export requirements in primarily two ways, namely through the responsible and correct use of pesticides and through the accurate, internationally recognised measurement and monitoring of pesticide residues (Frohberg et al., 2006; DAFF, 2009, 2010). The European Commission's (EC) Rapid Alert System for Food and Feed (RASFF) identifies risks in food and feed imported into the EU (EU, 2011). Depending on the risk level, the EC will either prohibit the consignment from entering the country (border rejection) or send out an alert notification or an information notification. The former requires immediate corrective action, i.e., withdraw/recall of the product, while the latter requires precautions to be taken in future to avoid further notifications (EU, 2011, 2009). Since 2000, South Africa has received only 4 information notifications and one alert notification for pesticide residues detected on fruit. The detected pesticides were omethoate, dimethoate and ethephon in grapes; methomyl in pears and prophenophos in peppers. The majority of South African border rejections and notifications are due to MRLs being exceeded for aflatoxins in groundnuts. In general the mycotoxin hazard category tends to dominate as the main cause for border rejection in the EU across all importers (EU, 2011, 2009).

In accordance with Article 12 of EU Regulation 882/2004 (EU, 2004), laboratories designated for official control of pesticide residues within the EU must be accredited to ISO/IEC 17025. Accreditation of laboratories is seen as the most effective way of defeating non-tariff technical barriers to trade (for example, eliminating doubt on the quality of test results from exporting countries). For export purposes, measurements performed by analytical laboratories who are accredited to ISO 17025, are internationally accepted, in terms of the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement (ILAC MRA) for trade, of which South Africa is a signatory since November 2000 (ILAC), 2001). Although there are several laboratories analysing pesticide residues in South Africa (National Laboratory Association (NLA), 2010), according to the South African National Accreditation System (SANAS), (SANAS, 2010), there are only nine ISO 17025 accredited analytical laboratories in South Africa capable of analysing pesticide residues in food and feed. Of these laboratories, two are able to analyse the raw and finished products of pesticide formulations (SANAS, 2010). There are two government entities responsible for pesticide residue measurements in food and plant products in South Africa, namely the Department of Agriculture, Forestry and Fisheries and the Department of Health (DoH). Fresh produce for export is well monitored by the Perishable Products Export Control Board (PPECB). The PPECB is South Africa's official certification agency for the export of perishable products. It is mandated by the Department of Agriculture to deliver cold chain services in terms of the PPECB Act, No.9 of 1983 and delivers inspection and food safety services, under the APS Act, No.119 of 1990. The PPECB is also responsible for monitoring imported consignments of fresh produce. The PPECB is ISO 17025 accredited for the analysis of mycotoxins in various plant products (PPECB, 2011). The DoH Food Control Directorate has inspectors that regularly sample food items from the local trade industry; the analysis of which is outsourced to private accredited laboratories with the capacity to conduct extensive analyses.

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 75

famers plant GM maize or cotton. Based on surface area, South Africa is currently ranked 9th worldwide in planting GM crops (James, 2011). The benefits as well as possible disadvantages of planting Bt maize, from a South African famers perspective was reported

Although many benefits may be associated with the use of GM crops for pest control, there are also a number of disadvantages. From an environmental and human-health perspective,

• While many broad-spectrum insecticides reduce the impact of biological control agents that help to control insect and mite pests, studies indicated that Bt maize is compatible with biological control and has little effect on the natural enemies of pests (Bessin,

• Control of lepidopteran pests with Bt endotoxins provides several advantages from the grower's perspective. These benefits could be particularly important in subsistence agriculture where literacy levels of farmers are low and extension support is poor or lacking. Control is no longer affected by the weather. The crop is protected even if the field conditions are not suitable for aerial or ground application of insecticides

• A related advantage is the protection of plant parts that are difficult to reach with insecticide spraying or the protection of new growth that emerges after spray

• The crop is also protected continuously in the field and the laborious task of scouting to

For example, reduced insecticide use was reported from the Makathini Flats region of Kwa-Zulu Natal, South Africa, where 95% of smallholder (1-3 hectares) cotton producers grew rain-fed Bt cotton. Farmers that adopted Bt cotton reported reduced insecticide use and a reduction in labour (Ismael et al., 2001). A typical farmer, often a woman, was spared 12 days of arduous spraying, saving more than a 1 000 litres of water that would have been used in pesticide application (Conway, 2004). Similar benefits have been reported in smallscale maize farming systems in South Africa. Between 16 and 62% higher yields were reported with Bt maize above the conventional iso-line (Gouse, 2005) due to improved stem borer control. Bt maize adopting-farmers were better off than farmers who planted conventional hybrids, despite the additional technology fee in terms of seed costs (Gouse, 2005). A reduction in pesticide application also reduces the potential pesticide drift onto other crops or environmentally sensitive areas (Meeusen & Warren, 1989). Because the active Bt toxin material is produced directly in the crop tissue, concerns such as spray drift and groundwater contamination are precluded (Meeusen & Warren, 1989). Therefore, the use of transgenic crops reduces the use of insecticides, minimizes the impact of these chemicals on non-target organisms, and has positive health consequences for farm workers

Although GM crops have become a major component of insect control strategies, a proper perspective of its potential demands a close look at limitations and uncertainties that may reduce its future impact on agriculture. Since the first deployment of Bt crops there has been concern with regard to the development of resistance of target pests and potential non-target organism effects (Tabashnik, 1994; Gould, 1998). For this reason,

applications like tillers and ears of maize (Meeusen & Warren, 1989);

• Finally, and most importantly, is the reduction in insecticide applications.

by Kruger et al. (2009, 2011) and that of Bt cotton by Mellet et al. (2003).

the use of genetically modified crops has several benefits.

timeously detect pest infestations may be reduced;

2010);

(Meeusen & Warren, 1989);

themselves (Barton & Dracup, 2000).

The DoH, currently does not have the capacity to test a large number of samples for residues. As with several non-accredited facilities in South Africa, reasons for local laboratories not being able to obtain accreditation for residue monitoring include (Apps, 2007; Dlamini, 2007; Fernandes-Whaley, 2009):

There has been concern that the ever-decreasing MRLs for pesticide residues on food may be considered as technical barriers to trade, especially for developing countries in Africa (Urquhart, 1999; Frohberg, 2006; String Communication, 2007). This may be true, especially for countries in the regions without the necessary technical infrastructure, analytical capability and skills. However, in South Africa, recent proactive investment by government and industry has been implemented into improving the analytical infrastructure for pesticide residues on food (Aldrich & Street, 1964; SABS, 2011), although the lack of skilled human resources still remains a limitation (Apps, 2007; Dlamini, 2007; Fernandes-Whaley, 2009). South Africa currently has nine ISO 17025 accredited laboratories for pesticide residue analysis in plant products. Most of these accredited facilities have obtained technique accreditation for pesticide residues on processed foods and plant products using state-of-the art gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry techniques, which are able to meet EU MRL requirements and thereby ensuring trade within the South African framework.

#### **4. Alternatives to the use of pesticides in agricultural pest control**

In recent years there have been fast developments in alternate pest control mechanisms to reduce environmental levels of organic and inorganic pesticides. One of these developments is genetically modified (GM) crops, such as GM maize and cotton. Sprays of the bacteria, *Bacillus thuringiensis* (Bt), have been used to control pests for decades. The crystalline (cry) protein produced by this bacteria kills certain insect species and was reported to have limited effects on most non-target species (Schnepf et al., 1998). The use of commercial Bt sprays have, however, been limited due to their relatively high cost, poor crop coverage, rapid environmental inactivation, and less than desirable level of pest control, especially when compared with less expensive conventional chemical insecticides (Benedict & Altman, 2001).

More recently, toxin-encoding genes from *B. thuringiensis* have been expressed in transgenic crop plants, providing protection from some key pests (Schnepf et al., 1998). In South Africa two of these key pests of maize are the lepidopteran stem borers, *Busseola fusca* (Lepidoptera: Noctuidae) and *Chilo partellus* (Lepidoptera: Crambidae) which are of economic importance throughout Southern and Eastern Africa. Large-scale planting of Bt crops to control these pests in South Africa commenced during 1998. Bt cotton for control of the boll worm complex, particularly the African bollworm, *Helicoverpa armigera* (Lepidoptera: Noctuidae), was also introduced into South Africa during 1998. Adoption rates of Bt maize and cotton were high and in many areas of the country, more than 90% of

The DoH, currently does not have the capacity to test a large number of samples for residues. As with several non-accredited facilities in South Africa, reasons for local laboratories not being able to obtain accreditation for residue monitoring include (Apps,

• and lack of appropriate reference materials and the high cost of proficiency testing (PT)

There has been concern that the ever-decreasing MRLs for pesticide residues on food may be considered as technical barriers to trade, especially for developing countries in Africa (Urquhart, 1999; Frohberg, 2006; String Communication, 2007). This may be true, especially for countries in the regions without the necessary technical infrastructure, analytical capability and skills. However, in South Africa, recent proactive investment by government and industry has been implemented into improving the analytical infrastructure for pesticide residues on food (Aldrich & Street, 1964; SABS, 2011), although the lack of skilled human resources still remains a limitation (Apps, 2007; Dlamini, 2007; Fernandes-Whaley, 2009). South Africa currently has nine ISO 17025 accredited laboratories for pesticide residue analysis in plant products. Most of these accredited facilities have obtained technique accreditation for pesticide residues on processed foods and plant products using state-of-the art gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry techniques, which are able to meet EU MRL requirements and thereby

• poor financing for analytical equipment required to meet stringent MRLs,

**4. Alternatives to the use of pesticides in agricultural pest control**

In recent years there have been fast developments in alternate pest control mechanisms to reduce environmental levels of organic and inorganic pesticides. One of these developments is genetically modified (GM) crops, such as GM maize and cotton. Sprays of the bacteria, *Bacillus thuringiensis* (Bt), have been used to control pests for decades. The crystalline (cry) protein produced by this bacteria kills certain insect species and was reported to have limited effects on most non-target species (Schnepf et al., 1998). The use of commercial Bt sprays have, however, been limited due to their relatively high cost, poor crop coverage, rapid environmental inactivation, and less than desirable level of pest control, especially when compared with less expensive conventional chemical insecticides

More recently, toxin-encoding genes from *B. thuringiensis* have been expressed in transgenic crop plants, providing protection from some key pests (Schnepf et al., 1998). In South Africa two of these key pests of maize are the lepidopteran stem borers, *Busseola fusca* (Lepidoptera: Noctuidae) and *Chilo partellus* (Lepidoptera: Crambidae) which are of economic importance throughout Southern and Eastern Africa. Large-scale planting of Bt crops to control these pests in South Africa commenced during 1998. Bt cotton for control of the boll worm complex, particularly the African bollworm, *Helicoverpa armigera* (Lepidoptera: Noctuidae), was also introduced into South Africa during 1998. Adoption rates of Bt maize and cotton were high and in many areas of the country, more than 90% of

2007; Dlamini, 2007; Fernandes-Whaley, 2009): • a high turnover of analysts in the laboratory, • lack of skilled, competent technicians,

ensuring trade within the South African framework.

scheme participation.

(Benedict & Altman, 2001).

famers plant GM maize or cotton. Based on surface area, South Africa is currently ranked 9th worldwide in planting GM crops (James, 2011). The benefits as well as possible disadvantages of planting Bt maize, from a South African famers perspective was reported by Kruger et al. (2009, 2011) and that of Bt cotton by Mellet et al. (2003).

Although many benefits may be associated with the use of GM crops for pest control, there are also a number of disadvantages. From an environmental and human-health perspective, the use of genetically modified crops has several benefits.

For example, reduced insecticide use was reported from the Makathini Flats region of Kwa-Zulu Natal, South Africa, where 95% of smallholder (1-3 hectares) cotton producers grew rain-fed Bt cotton. Farmers that adopted Bt cotton reported reduced insecticide use and a reduction in labour (Ismael et al., 2001). A typical farmer, often a woman, was spared 12 days of arduous spraying, saving more than a 1 000 litres of water that would have been used in pesticide application (Conway, 2004). Similar benefits have been reported in smallscale maize farming systems in South Africa. Between 16 and 62% higher yields were reported with Bt maize above the conventional iso-line (Gouse, 2005) due to improved stem borer control. Bt maize adopting-farmers were better off than farmers who planted conventional hybrids, despite the additional technology fee in terms of seed costs (Gouse, 2005). A reduction in pesticide application also reduces the potential pesticide drift onto other crops or environmentally sensitive areas (Meeusen & Warren, 1989). Because the active Bt toxin material is produced directly in the crop tissue, concerns such as spray drift and groundwater contamination are precluded (Meeusen & Warren, 1989). Therefore, the use of transgenic crops reduces the use of insecticides, minimizes the impact of these chemicals on non-target organisms, and has positive health consequences for farm workers themselves (Barton & Dracup, 2000).

Although GM crops have become a major component of insect control strategies, a proper perspective of its potential demands a close look at limitations and uncertainties that may reduce its future impact on agriculture. Since the first deployment of Bt crops there has been concern with regard to the development of resistance of target pests and potential non-target organism effects (Tabashnik, 1994; Gould, 1998). For this reason,

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 77

In South Africa, as in many countries with temperate climates, pesticides are crucial not only in the agricultural setting but also in the management of disease vectors. For South Africa, malaria is the only disease currently managed in this manner. Since before the 2nd World War, malaria in South Africa has been controlled by means of ecological and biological control, as well as with oil and Paris green as a larvicide. Also, a weekly indoor application of pyrethrum has been used since 1943. Since the middle 1940s, the availability of DDT and hexachlorobenzene meant that Indoor Residual Spraying (IRS) with insecticides, a technique developed in South Africa by de Meillon in the 1930s (de Meillon, 1936), became the mainstay for effective malaria control worldwide (Sharp et al., 1988; Musawenkosi et al.,

The insecticides are sprayed on indoor walls and roof beams, as well as outside under the eaves. The residual insecticide then kills female mosquitoes, interrupting transmission from a person with malaria to an uninfected person. The rates of malaria dropped significantly with the use of DDT, and many lives have been saved in this manner (Bouwman et al. 2011). However, in 1996, DDT was replaced with pyrethroids as IRS in South Africa. The rates of infections and deaths climbed dramatically, forcing the reintroduction of DDT in 2000 (Hargreaves et al., 2000; Maharaj et al., 2005). Infection and mortality rates have now returned to original levels, and pyrethroids are used in some places. In 2009 in South Africa, 6 072 people contracted malaria and 45 died (WHO, 2010). During the same year, an estimated 236 million people contracted malaria globally, resulting in nearly 781 000 deaths of which more than 90% were from Africa. This indicates a dire need for expanded and

In South Africa, the registration of DDT for all purposes except malaria control was withdrawn in 1976, with all resale and use of hexachlorobenzene (HCB) and DDT prohibited since 1983 (Bouwman, 2003). DDT continues to be used in malaria control as indicated above, but this use often leads to exposure of both the inhabitants of the sprayed houses, as well as the immediate environments. At a rate of 2 g m-2, an average house receives anywhere between 80 – 200 g per year. Seen that this is applied mainly indoors, a continuously enriched DDT environment is created. Since DDT is also semivolatile, it is present throughout the year in air in the homes, and probably redistributes itself to furniture and food inside (van Dyk et al., 2010). This continuous redistribution, adds to uptake opportunities that are reflected in the high levels of DDT found in inhabitants (Bouwman et al., 2006). The highest levels of DDT in blood were found in breast feeding infants of mothers living in sprayed houses (Bouwman et al., 1992). Van Dyk et al., (2010) suggests that a Total Homestead Environment Approach (THEA) should be followed when looking at exposure, uptake and exposure reduction

Very little research has been conducted on the effects in people living in sprayed houses, but in 2009, Bornman et al. published convincing associations between living in DDT-sprayed villages and urogenital malformations in baby boys from the Limpopo Province. Eskenazi et al. (2009) reviewed 494 studies published between 2003 and 2008 and found that "...*DDT and its breakdown product DDE may be associated with adverse health outcomes such as breast cancer, diabetes, decreased semen quality, spontaneous abortion, and impaired neurodevelopment in children*." Subsequently, Bouwman et al. (2011), based on further assessment of information,

**5. Pesticides used to control disease vectors**

improved malaria control measures.

opportunities.

2004).

studies have been conducted to prioritise non-target Lepidoptera species for further research in South Africa (Van Wyk et al., 2007). Bt maize seed is more expensive than comparable non-Bt seed and is only an advantage when a specific insect pest is present. Wind-mediated gene-flow and cross-pollination of landraces (local variety of the plant species) of crops can result in "contamination" of maize fields within several hundred meters from GM crop fields. This may present a problem for organic farmers or in cases where it is important to keep the grain Bt-free. This could also be important in the development of target pest resistance since the uncontrolled presence of the Bt-gene in landraces results in reduced expression of the cry protein and subsequent increased survival of the target pest in crops.

Another potential disadvantage is that biotechnology is being pursued to repair the problems caused by previous agrochemical technologies. Since more than 500 species of pests have already developed resistance to conventional insecticides, pests can also evolve resistance to Bt toxin in GM crops (Altieri, 2004). Resistance of the target pest of Bt maize in South Africa, the African stem borer was reported by Van Rensburg (2007) and Kruger et al., (2009) who reported a further increase in the geographic spread of resistance. The most significant environmental threat of resistance development is the subsequent reversal to the use of broad-spectrum insecticides, which is currently the case in South Africa (Kruger et al., 2011).

The challenge for the sustained use of GM technology in South Africa and especially in developing agriculture throughout Africa is the management of these crops to delay resistance development and to prolong the usefulness of the technology. On its own, insecticidal GM crops will not be the solution to pest problems. Over reliance on this technology may be its downfall and only an integrated approach to pest management will be effective on a long-term basis.

One example of an effective alternative to Bt maize for the management of stem borers is the "push-pull" habitat management systems that has been adopted by between 20 000 – 30 000 farmers in East Africa. As part of a novel approach to control stem borers in cereal crops, the International Centre of Insect Physiology and Ecology (ICIPE) developed habitat management strategies for farmers in resource-poor regions of East Africa (Khan et al*.,* 2000). In the push-pull system, trap and repellent plants are used to control populations of stem borers. Insects are trapped on highly susceptible trap plants (pull) and repelled from the main crop by repellent intercrops (push). Khan et al. (1997) observed that the two fodder crops, namely Napier grass (*Pennisetum purpureum*) and Sudan grass (*Sorghum sudanensis*) attract significantly more oviposition than maize. These grasses were consequently used in further developing habitat management strategies for stem borers. It was reported that planting Sudan grass as a border around maize plots reduced stem borer numbers in maize by 30% while only 20% of larvae on Napier grass survived, although this species was preferred by stem borers. The volatiles of non-hosts such as Molasses grass (*Melinis minutiflora*) can have a marked impact on reducing borer infestations on maize (Khan et al., 1997). It was discovered that these volatiles repel the stem borers, but attract their natural enemies (Khan et al., 2000). A push–pull system that combines the repellent *M. minutiflora* grass with a highly attractant plant like Napier grass would fit in well with farmers practising a mixed agricultural system. These alternatives in totality, if managed correctly, can help to reduce the widespread use of agricultural pesticides in modern farming practices.

#### **5. Pesticides used to control disease vectors**

76 Pesticides in the Modern World – Pesticides Use and Management

studies have been conducted to prioritise non-target Lepidoptera species for further research in South Africa (Van Wyk et al., 2007). Bt maize seed is more expensive than comparable non-Bt seed and is only an advantage when a specific insect pest is present. Wind-mediated gene-flow and cross-pollination of landraces (local variety of the plant species) of crops can result in "contamination" of maize fields within several hundred meters from GM crop fields. This may present a problem for organic farmers or in cases where it is important to keep the grain Bt-free. This could also be important in the development of target pest resistance since the uncontrolled presence of the Bt-gene in landraces results in reduced expression of the cry protein and subsequent increased

Another potential disadvantage is that biotechnology is being pursued to repair the problems caused by previous agrochemical technologies. Since more than 500 species of pests have already developed resistance to conventional insecticides, pests can also evolve resistance to Bt toxin in GM crops (Altieri, 2004). Resistance of the target pest of Bt maize in South Africa, the African stem borer was reported by Van Rensburg (2007) and Kruger et al., (2009) who reported a further increase in the geographic spread of resistance. The most significant environmental threat of resistance development is the subsequent reversal to the use of broad-spectrum insecticides, which is currently the case in South Africa (Kruger et al.,

The challenge for the sustained use of GM technology in South Africa and especially in developing agriculture throughout Africa is the management of these crops to delay resistance development and to prolong the usefulness of the technology. On its own, insecticidal GM crops will not be the solution to pest problems. Over reliance on this technology may be its downfall and only an integrated approach to pest management will

One example of an effective alternative to Bt maize for the management of stem borers is the "push-pull" habitat management systems that has been adopted by between 20 000 – 30 000 farmers in East Africa. As part of a novel approach to control stem borers in cereal crops, the International Centre of Insect Physiology and Ecology (ICIPE) developed habitat management strategies for farmers in resource-poor regions of East Africa (Khan et al*.,* 2000). In the push-pull system, trap and repellent plants are used to control populations of stem borers. Insects are trapped on highly susceptible trap plants (pull) and repelled from the main crop by repellent intercrops (push). Khan et al. (1997) observed that the two fodder crops, namely Napier grass (*Pennisetum purpureum*) and Sudan grass (*Sorghum sudanensis*) attract significantly more oviposition than maize. These grasses were consequently used in further developing habitat management strategies for stem borers. It was reported that planting Sudan grass as a border around maize plots reduced stem borer numbers in maize by 30% while only 20% of larvae on Napier grass survived, although this species was preferred by stem borers. The volatiles of non-hosts such as Molasses grass (*Melinis minutiflora*) can have a marked impact on reducing borer infestations on maize (Khan et al., 1997). It was discovered that these volatiles repel the stem borers, but attract their natural enemies (Khan et al., 2000). A push–pull system that combines the repellent *M. minutiflora* grass with a highly attractant plant like Napier grass would fit in well with farmers practising a mixed agricultural system. These alternatives in totality, if managed correctly, can help to reduce the widespread use of agricultural

survival of the target pest in crops.

be effective on a long-term basis.

pesticides in modern farming practices.

2011).

In South Africa, as in many countries with temperate climates, pesticides are crucial not only in the agricultural setting but also in the management of disease vectors. For South Africa, malaria is the only disease currently managed in this manner. Since before the 2nd World War, malaria in South Africa has been controlled by means of ecological and biological control, as well as with oil and Paris green as a larvicide. Also, a weekly indoor application of pyrethrum has been used since 1943. Since the middle 1940s, the availability of DDT and hexachlorobenzene meant that Indoor Residual Spraying (IRS) with insecticides, a technique developed in South Africa by de Meillon in the 1930s (de Meillon, 1936), became the mainstay for effective malaria control worldwide (Sharp et al., 1988; Musawenkosi et al., 2004).

The insecticides are sprayed on indoor walls and roof beams, as well as outside under the eaves. The residual insecticide then kills female mosquitoes, interrupting transmission from a person with malaria to an uninfected person. The rates of malaria dropped significantly with the use of DDT, and many lives have been saved in this manner (Bouwman et al. 2011). However, in 1996, DDT was replaced with pyrethroids as IRS in South Africa. The rates of infections and deaths climbed dramatically, forcing the reintroduction of DDT in 2000 (Hargreaves et al., 2000; Maharaj et al., 2005). Infection and mortality rates have now returned to original levels, and pyrethroids are used in some places. In 2009 in South Africa, 6 072 people contracted malaria and 45 died (WHO, 2010). During the same year, an estimated 236 million people contracted malaria globally, resulting in nearly 781 000 deaths of which more than 90% were from Africa. This indicates a dire need for expanded and improved malaria control measures.

In South Africa, the registration of DDT for all purposes except malaria control was withdrawn in 1976, with all resale and use of hexachlorobenzene (HCB) and DDT prohibited since 1983 (Bouwman, 2003). DDT continues to be used in malaria control as indicated above, but this use often leads to exposure of both the inhabitants of the sprayed houses, as well as the immediate environments. At a rate of 2 g m-2, an average house receives anywhere between 80 – 200 g per year. Seen that this is applied mainly indoors, a continuously enriched DDT environment is created. Since DDT is also semivolatile, it is present throughout the year in air in the homes, and probably redistributes itself to furniture and food inside (van Dyk et al., 2010). This continuous redistribution, adds to uptake opportunities that are reflected in the high levels of DDT found in inhabitants (Bouwman et al., 2006). The highest levels of DDT in blood were found in breast feeding infants of mothers living in sprayed houses (Bouwman et al., 1992). Van Dyk et al., (2010) suggests that a Total Homestead Environment Approach (THEA) should be followed when looking at exposure, uptake and exposure reduction opportunities.

Very little research has been conducted on the effects in people living in sprayed houses, but in 2009, Bornman et al. published convincing associations between living in DDT-sprayed villages and urogenital malformations in baby boys from the Limpopo Province. Eskenazi et al. (2009) reviewed 494 studies published between 2003 and 2008 and found that "...*DDT and its breakdown product DDE may be associated with adverse health outcomes such as breast cancer, diabetes, decreased semen quality, spontaneous abortion, and impaired neurodevelopment in children*." Subsequently, Bouwman et al. (2011), based on further assessment of information,

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 79

to differentiate between historic and current applications as well as the use of statistical tools

3.6 HCB: 4.5

0.62

4.1

43

Table 2. Pesticide levels (pg m-3 or μg kg-1 or μg ℓ-1) reported in various publication from

**7. Case study: A baseline of organochlorine pesticide residues in soil and**

OCPs have been used extensively throughout the world for the protection of crops as well as the control of disease vectors (Kumar et al., 2008). Because of their detrimental effects, many of the OCPs are banned, or restricted to the control of disease vectors. However, due to their highly persistent nature and potential for long-range transport, residues of these chemicals are still found in areas where use had been banned for decades (Gong et al., 2007; Hung et al., 2007). These residues may pose chronic toxicity to animals and humans via air, water, and food intake (Darko et al., 2008). Due to the general lack of data on organochlorine pollution in soils and sediments from South Africa, the objective of this baseline study was to investigate the presence and concentration of OCPs in soil and sediment from an industrialised in addition to agriculturally impacted areas of South

Water 8 ∑DDT: LOD – 7 000 Barnhoorn et al.,

Pentachlorobenzene:

Heptachlorepoxide:

Chlorpyrifos: 0.085 Prothiofos: 0.032 Cypermethrin: LOD ∑ Endosulfan: 0.003 *p,p*'-DDE: 0.01

Atrazine: 1.2 – 9.3 Terbuthylazine: 1.04 –

∑DDT: 1.9 - 710 ∑HCH: 0.21 - 470 ∑Chlordanes: 0.12 - 11

HCB: 0.29 – 7.8 Mirex: 0.21 – 1.8

Toxaphene: 12

<sup>28</sup>∑DDT: 360 – 24 000 Barnhoorn et al.,

2009

2009

2007

2006

2005

2008

Batterman et al.,

Bollmohr et al.,

Du Preez et al,

Bouwman et al.,

**Land use or activity Matrix N Pesticide and levels Reference**

to determine variation within datasets.

Fat of indigenous

fish

Water 27

Wild bird eggs

**sediment from the Vaal Triangle, South Africa**

Mixed: large city Air 48

region Water 5

DDT used in IRS programme

DDT used in IRS programme

Agriculturally impacted estuary (apple, pear and plum

Corn-production

Various sampling areas across South

**7.1 Introduction**

orchards)

Africa

SA

Africa.

strongly suggested that DDT (that is currently considered as safe for use in malaria control) should now be considered in terms of precaution, with an urgent recommendation that exposure reductions be implemented. DDT does not remain restricted to the homestead environment. It is transported to adjacent sites and can be found in water, sediment, birds and fish near and far away from sprayed areas (Barnhoorn et al., 2009). The findings of urogenital malformations in baby boys by Bornman et al. (2009) are a further implication of the endocrine disruptive activities of DDT, DDE and DDD all have some kind of endocrine disruptive activity (as discussed previously), as implied by the findings of urogenital malformations in baby boys by Bornman et al. (2009). Intersex in tilapia fish has also been found in the major river that flows through the same area where the malformations were found (Barnhoorn, 2010).

The alternative insecticides used in IRS should not be ignored. Most of them are pyrtheroids such as deltamethrin and permethrin, but organophosphates such as malathion and primiphos-methyl, and bendiocarb, a carbamate, are also recommended by the WHO (2006). It has been noted though, that very little risk assessment of most of these compounds has been done with relevance to an IRS exposure scenario. Hopefully they are safe, but caution should be applied (Bouwman & Kylin, 2009), as pyrethroids have been found in the same breast milk as DDT (Bouwman et al., 2006), a potentially dangerous situation as toxic interactions have been detected in laboratory animals at relevant levels (Bouwman & Kylin, 2009).

These, often low-income, families are at an increased risk to DDT exposure and consequently the associated adverse health effects. People that are poverty stricken generally are at a higher risk to contract diseases due to malnutrition and lack of resources. When combined with the constant presence of HIV, these communities are more susceptible to health risks. Pesticide levels that would be of no real concern in healthy individuals could, theoretically be detrimental to people living in these communities. IRS using insecticides will undoubtedly remain in the arsenal of malaria control measures for a considerable period. However, as science and knowledge advances, urgent attention should be directed towards safer methods, exposure reductions, and better chemicals.

#### **6. Pesticides levels in the South African environment**

Many studies have focused on both historic and current use pesticide levels in South Africa. As can be seen in table 2, these levels are highly variable depending on the activity of the area as well as the sampling media. As previously described, levels are typically higher in biotic matrices as compared to abiotic matrices due to the effect of biomagnification, specifically in OCPs. DDT is still a prevalent pesticide although use outside of the malaria regions is strictly prohibited.

Most of these studies have concentrated on areas where there were high levels of expected impacts. Therefore a pilot study was done in 2006 to assess the levels of persistent organic pollutants including OCPs in an industrial area of South Africa concurrently with areas mainly impacted by agriculture. The focus was on industrial pollutants but this study was also used to assess the occurrence and distribution of OCPs in areas with a large variety of land use.

This pilot study is presented here as a typical research approach to gather and interpret data concerning pesticides in the environment. It gives a brief overview of commonly used ratio's **Land use or activity Matrix N Pesticide and levels Reference**  DDT used in IRS programme Water 8 ∑DDT: LOD – 7 000 Barnhoorn et al., 2009 DDT used in IRS programme Fat of indigenous fish <sup>28</sup>∑DDT: 360 – 24 000 Barnhoorn et al., 2009 Mixed: large city Air 48 Pentachlorobenzene: 3.6 HCB: 4.5 Heptachlorepoxide: 0.62 Toxaphene: 12 Batterman et al., 2007 Agriculturally impacted estuary (apple, pear and plum orchards) Water 27 Chlorpyrifos: 0.085 Prothiofos: 0.032 Cypermethrin: LOD ∑ Endosulfan: 0.003 *p,p*'-DDE: 0.01 Bollmohr et al., 2006 Corn-production region Water 5 Atrazine: 1.2 – 9.3 Terbuthylazine: 1.04 – 4.1 Du Preez et al, 2005 Various sampling areas across South Africa Wild bird eggs 43 ∑DDT: 1.9 - 710 ∑HCH: 0.21 - 470 ∑Chlordanes: 0.12 - 11 HCB: 0.29 – 7.8 Mirex: 0.21 – 1.8 Bouwman et al., 2008

to differentiate between historic and current applications as well as the use of statistical tools to determine variation within datasets.

Table 2. Pesticide levels (pg m-3 or μg kg-1 or μg ℓ-1) reported in various publication from SA

#### **7. Case study: A baseline of organochlorine pesticide residues in soil and sediment from the Vaal Triangle, South Africa**

#### **7.1 Introduction**

78 Pesticides in the Modern World – Pesticides Use and Management

strongly suggested that DDT (that is currently considered as safe for use in malaria control) should now be considered in terms of precaution, with an urgent recommendation that exposure reductions be implemented. DDT does not remain restricted to the homestead environment. It is transported to adjacent sites and can be found in water, sediment, birds and fish near and far away from sprayed areas (Barnhoorn et al., 2009). The findings of urogenital malformations in baby boys by Bornman et al. (2009) are a further implication of the endocrine disruptive activities of DDT, DDE and DDD all have some kind of endocrine disruptive activity (as discussed previously), as implied by the findings of urogenital malformations in baby boys by Bornman et al. (2009). Intersex in tilapia fish has also been found in the major river that flows through the same area where the malformations were

The alternative insecticides used in IRS should not be ignored. Most of them are pyrtheroids such as deltamethrin and permethrin, but organophosphates such as malathion and primiphos-methyl, and bendiocarb, a carbamate, are also recommended by the WHO (2006). It has been noted though, that very little risk assessment of most of these compounds has been done with relevance to an IRS exposure scenario. Hopefully they are safe, but caution should be applied (Bouwman & Kylin, 2009), as pyrethroids have been found in the same breast milk as DDT (Bouwman et al., 2006), a potentially dangerous situation as toxic interactions have

These, often low-income, families are at an increased risk to DDT exposure and consequently the associated adverse health effects. People that are poverty stricken generally are at a higher risk to contract diseases due to malnutrition and lack of resources. When combined with the constant presence of HIV, these communities are more susceptible to health risks. Pesticide levels that would be of no real concern in healthy individuals could, theoretically be detrimental to people living in these communities. IRS using insecticides will undoubtedly remain in the arsenal of malaria control measures for a considerable period. However, as science and knowledge advances, urgent attention should be directed towards safer methods, exposure

Many studies have focused on both historic and current use pesticide levels in South Africa. As can be seen in table 2, these levels are highly variable depending on the activity of the area as well as the sampling media. As previously described, levels are typically higher in biotic matrices as compared to abiotic matrices due to the effect of biomagnification, specifically in OCPs. DDT is still a prevalent pesticide although use outside of the malaria

Most of these studies have concentrated on areas where there were high levels of expected impacts. Therefore a pilot study was done in 2006 to assess the levels of persistent organic pollutants including OCPs in an industrial area of South Africa concurrently with areas mainly impacted by agriculture. The focus was on industrial pollutants but this study was also used to assess the occurrence and distribution of OCPs in areas with a large variety of

This pilot study is presented here as a typical research approach to gather and interpret data concerning pesticides in the environment. It gives a brief overview of commonly used ratio's

been detected in laboratory animals at relevant levels (Bouwman & Kylin, 2009).

**6. Pesticides levels in the South African environment**

found (Barnhoorn, 2010).

reductions, and better chemicals.

regions is strictly prohibited.

land use.

OCPs have been used extensively throughout the world for the protection of crops as well as the control of disease vectors (Kumar et al., 2008). Because of their detrimental effects, many of the OCPs are banned, or restricted to the control of disease vectors. However, due to their highly persistent nature and potential for long-range transport, residues of these chemicals are still found in areas where use had been banned for decades (Gong et al., 2007; Hung et al., 2007). These residues may pose chronic toxicity to animals and humans via air, water, and food intake (Darko et al., 2008). Due to the general lack of data on organochlorine pollution in soils and sediments from South Africa, the objective of this baseline study was to investigate the presence and concentration of OCPs in soil and sediment from an industrialised in addition to agriculturally impacted areas of South Africa.

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 81

The concentration of OCPs at all the sites was relatively low when compared with literature (Table 3) from other countries. ∑OCPs measured ranged between 0.58 - 6.9 ng g-1 with the highest values found in Vanderbijlpark soil (Vnd-Inf-Soil & Vnd-Ind-Soil), and sediment from the Klip River (KlipRiv) (Figure 2). Vanderbijlpark is a highly industrialised area with ferrous and non-ferrous industries, with some farming activities. The largest contributor of the OCPs in soil sites was *p,p'*-DDE measured in Vnd-Inf-Soil and Vnd-Ind-Soil (6.61 - 4.82 ng g-1), followed by γ-HCH (1.7 ng g-1) in S-Ind-Soil and *p,p'*-DDE (1.1 ng g-1) in Vnd-Inf-Soil. The Klip River (a tributary of the Vaal River) has a large catchment area that includes the industrial and residential areas of Soweto, Lenasia, Meyerton and Vereeniging. As with Vnd-Inf-Soil, the largest contribution to sediment was from *p,p'*-DDT (3.7 ng g-1) followed by α-HCH (0.58 ng g-1).

RietSpr

**R42**

**5 km**

Fig. 1. Map of South Africa and its provinces; indication the location of the sampling sites in

Levels from South Africa and Brazil are in the same order of magnitude for DDT and HCH, with levels in Morocco being lower for these two compounds but higher for endosulfan (Table 3). It should be taken into account that China is currently the largest producer of DDT for vector control, as well as the pesticide dicofol (Cheung *et al*., 2007) that may contain DDT as contaminant, this would explain the higher DDT levels (Table 3). On the other hand, the high average levels reported in the Canadian study were mainly

**FREESTATE**

**GAUTENG**

**Zimbabwe**

**Swaziland**

**Mozambique**

*Natal*

*Kwazulu*

*Mpumalanga*

*Limpopo*

*Vaal Triangle*

*Free State*

*Eastern Cape*

*Gauteng*

**Lesotho**

*North-West*

**Botswana**

Vdb-Inf-Soil Vdp-Ind-Soil

**R57**

**Sasolburg**

**R59**

**Vaal River**

S-Inf-Soil

S-Ind-Soil

**Vanderbijlpark**

**Klip River Riet Spruit**

Bordering country Ocean Town/City

TbosSpr

**Taaibos Spruit**

VaalRivV

**Vereeniging**

DDT sprayed areas in South Africa

KlipRiv

**R82**

SkbrRiv3

**RX** Major roads River/Streams North

> **Suikerbosrand River**

**R716**

**Vaal River**

**R42**

**7.2.4 Results and discussion**

*Western Cape*

the areas assessed for OCPs.

attributed to a single site.

**Namibia**

**500 km**

**South Africa** *Northern Cape*

#### **7.2 Materials and methods**

#### **7.2.1 Sampling area**

The Vaal Triangle is a highly industrialised area in central South Africa (Figure 1) with a population of approximately 790 000. The main industries in the area include ferrous and non-ferrous metal production and petrochemical processes. There is also limited farming activity, mainly consisting of maize and cattle. Soil was collected in the industrial (Vdb-Ind-Soil and S-Ind-Soil) and low-income residential areas (Vdb-Inf-Soil and S-Inf-Soil) close to these industries. Sediment was collected from rivers and streams including the Vaal River (VaalRivV) and its tributaries; Riet Spruit (RietSpr), Klip River (KlipRiv), Suikerbosrand River (SkbrRiv3) and the Taaibos Spruit (TbosSpr) (Figure 1). Concurrently, sediment was collected from agricultural areas upstream and downstream of the Vaal Triangle: SkbrRiv1 and SkbrRiv2, east of the Vaal Triangle and VaalRivK, in the Vaal River approximately 70 km downstream of Vanderbijlpark inside the Vredefort Dome World Heritage Site, and a site in the Orange River (OrangeRiv) just after the confluence with the Vaal River. Agriculture in the Vredefort Dome is comparable to that of the Vaal Triangle while the Orange River catchment is impacted by the cultivation of a variety of other crops (wheat, cotton, potatoes, as well as fruit). There are no malaria control activities in this area; the closest malaria control activity is 260 km away towards the Mozambican border (Figure 1).

#### **7.2.2 Sample extraction, clean up and analysis**

Extraction and analysis for DDT, dicofol, endosulfan and hexachlorocyclohexane (HCH) was done under Norwegian accreditation at NILU in Norway. Analytical details are given in Bengtson Nash et al.(2008) and Knutzen (2003). In short: samples were spiked with 13Clabelled analogs of the analytes and extracted with cyclohexane. Interfering molecules were removed through size exclusion chromatography and sulphuric acid clean-up. Before quantification, the samples were spiked with a recovery control standard. Analytical quantification was using gas chromatography coupled with high resolution mass spectrometry (GC-HRMS; Agilent 6890N GC coupled to an Micromass Waters Autospec HRMS, Manchester UK). The HRMS was operated at a resolution of >10 000 using electron ionization. Two masses were monitored for each isotope cluster of both the analyte and the added 13C-labelled surrogate. The recoveries of the added internal standard compounds were also established. Procedural blanks were run throughout. The limit of quantification was set to the detection limit based on at least five consecutive blank samples plus three standard deviations. All concentrations are reported on a mass basis. The following conditions had to be met for an unequivocal identification and quantification of the analytes: (1) correct retention time (2) signal-to-noise ratio greater than 3:1, (3) correct recovery of the internal standard, and (4) acceptable blank values of the complete clean-up and quantification procedures.

#### **7.2.3 Statistical analysis**

The software package used for statistical analyses was STATISTICA (version 8). Normal distribution was tested using the Shapiro-Wilk test and groups were compared using the Mann-Whitney U test. Principal component analysis (PCA), using all of the congener data, with data transformations according to Howell (2007), was performed with CANOCO (version 4.5) to investigate the pollutant patterns at the sites, as well as possible differences in the matrices sampled.

#### **7.2.4 Results and discussion**

80 Pesticides in the Modern World – Pesticides Use and Management

The Vaal Triangle is a highly industrialised area in central South Africa (Figure 1) with a population of approximately 790 000. The main industries in the area include ferrous and non-ferrous metal production and petrochemical processes. There is also limited farming activity, mainly consisting of maize and cattle. Soil was collected in the industrial (Vdb-Ind-Soil and S-Ind-Soil) and low-income residential areas (Vdb-Inf-Soil and S-Inf-Soil) close to these industries. Sediment was collected from rivers and streams including the Vaal River (VaalRivV) and its tributaries; Riet Spruit (RietSpr), Klip River (KlipRiv), Suikerbosrand River (SkbrRiv3) and the Taaibos Spruit (TbosSpr) (Figure 1). Concurrently, sediment was collected from agricultural areas upstream and downstream of the Vaal Triangle: SkbrRiv1 and SkbrRiv2, east of the Vaal Triangle and VaalRivK, in the Vaal River approximately 70 km downstream of Vanderbijlpark inside the Vredefort Dome World Heritage Site, and a site in the Orange River (OrangeRiv) just after the confluence with the Vaal River. Agriculture in the Vredefort Dome is comparable to that of the Vaal Triangle while the Orange River catchment is impacted by the cultivation of a variety of other crops (wheat, cotton, potatoes, as well as fruit). There are no malaria control activities in this area; the closest malaria control activity is 260 km away towards the Mozambican border (Figure 1).

Extraction and analysis for DDT, dicofol, endosulfan and hexachlorocyclohexane (HCH) was done under Norwegian accreditation at NILU in Norway. Analytical details are given in Bengtson Nash et al.(2008) and Knutzen (2003). In short: samples were spiked with 13Clabelled analogs of the analytes and extracted with cyclohexane. Interfering molecules were removed through size exclusion chromatography and sulphuric acid clean-up. Before quantification, the samples were spiked with a recovery control standard. Analytical quantification was using gas chromatography coupled with high resolution mass spectrometry (GC-HRMS; Agilent 6890N GC coupled to an Micromass Waters Autospec HRMS, Manchester UK). The HRMS was operated at a resolution of >10 000 using electron ionization. Two masses were monitored for each isotope cluster of both the analyte and the added 13C-labelled surrogate. The recoveries of the added internal standard compounds were also established. Procedural blanks were run throughout. The limit of quantification was set to the detection limit based on at least five consecutive blank samples plus three standard deviations. All concentrations are reported on a mass basis. The following conditions had to be met for an unequivocal identification and quantification of the analytes: (1) correct retention time (2) signal-to-noise ratio greater than 3:1, (3) correct recovery of the internal standard, and (4) acceptable blank values of the complete clean-up and

The software package used for statistical analyses was STATISTICA (version 8). Normal distribution was tested using the Shapiro-Wilk test and groups were compared using the Mann-Whitney U test. Principal component analysis (PCA), using all of the congener data, with data transformations according to Howell (2007), was performed with CANOCO (version 4.5) to investigate the pollutant patterns at the sites, as well as possible differences

**7.2 Materials and methods 7.2.1 Sampling area**

**7.2.2 Sample extraction, clean up and analysis**

quantification procedures.

**7.2.3 Statistical analysis**

in the matrices sampled.

The concentration of OCPs at all the sites was relatively low when compared with literature (Table 3) from other countries. ∑OCPs measured ranged between 0.58 - 6.9 ng g-1 with the highest values found in Vanderbijlpark soil (Vnd-Inf-Soil & Vnd-Ind-Soil), and sediment from the Klip River (KlipRiv) (Figure 2). Vanderbijlpark is a highly industrialised area with ferrous and non-ferrous industries, with some farming activities. The largest contributor of the OCPs in soil sites was *p,p'*-DDE measured in Vnd-Inf-Soil and Vnd-Ind-Soil (6.61 - 4.82 ng g-1), followed by γ-HCH (1.7 ng g-1) in S-Ind-Soil and *p,p'*-DDE (1.1 ng g-1) in Vnd-Inf-Soil. The Klip River (a tributary of the Vaal River) has a large catchment area that includes the industrial and residential areas of Soweto, Lenasia, Meyerton and Vereeniging. As with Vnd-Inf-Soil, the largest contribution to sediment was from *p,p'*-DDT (3.7 ng g-1) followed by α-HCH (0.58 ng g-1).

Fig. 1. Map of South Africa and its provinces; indication the location of the sampling sites in the areas assessed for OCPs.

Levels from South Africa and Brazil are in the same order of magnitude for DDT and HCH, with levels in Morocco being lower for these two compounds but higher for endosulfan (Table 3). It should be taken into account that China is currently the largest producer of DDT for vector control, as well as the pesticide dicofol (Cheung *et al*., 2007) that may contain DDT as contaminant, this would explain the higher DDT levels (Table 3). On the other hand, the high average levels reported in the Canadian study were mainly attributed to a single site.

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 83

**Sampling site**

The ΣHCH concentration in soil varied between 0.17 - 1.86 ng g-1 with the highest concentration measured at Sasolburg (S-Ind-Soil) in soil collected close to the petrochemical plant. The lowest level was measured in the low-income residential area in Vanderbijlpark (Vdb-Inf-Soil). In sediment, the concentration varied between 0.3 - 1.7 ng g-1, with the highest concentration measured in the predominantly agricultural area of the Orange River (OrangeRiv). The values for HCH are in the same order of magnitude as determined in

Lindane consists of a mixture of all HCH isomers with approximately 90% γ-HCH (Wang et al., 2007). In technical HCH, the isomer ratio is different with α-HCH representing 55 – 80% of the total mixture (Gong et al., 2007). In both soil and sediments, γ-HCH was the most prevalent with more than 80% contribution to ΣHCH levels (Table 4), followed by β-HCH and α-HCH. This points to recent use of lindane rather than technical HCH or historic inputs, since γ-HCH is degraded more rapidly than α-HCH both under aerobic and

> Concentration range ΣHCH (ng g-1)

Soil 4 0.70 1.9 – 0.17 4 12 85 Sediment 9 0.52 0.2 – 1.7 5 6 89

Table 4. Summary of mean HCH values and percentage contribution of each isomer for soil

DDT, in use since the Second World War, was the first internationally used pesticide due to its highly effective insecticidal properties and ease of manufacture (Stenersen, 2004). DDT is often found in the environment even in areas where it is not currently applied due to its highly persistent nature and ability to be passively (wind and water) and actively (through biota)

% α-HCH % β-

HCH % γ-HCH

Fig. 2. Distribution patterns of different OCPs between sites

Mean ΣHCH (ng g-1) ∑ DDT ∑ HCH Dicofol ∑ Endosulfan

other studies (Table 3).

Matrix Nr of

**7.4 DDT and dicofol**

and sediment

anaerobic conditions (Wu et al., 1997).

samples

**Concentration (ng g-1)**

The lowest OCP levels for the South African study were measured in the Taaibos Spruit (TbosSpr), which receives run-off impacted by low-income residential areas as well as petrochemical industries. The OCP levels for sites primarily influenced by agricultural activities ranged between 2.3 - 0.59 ng/g (Figure 2). Of the four classes of OCPs (ΣDDT, dicofol, ΣHCH and Σendosulfan), ΣDDT was the highest at all sites, except for one sediment site in an agricultural area (OrangeRiv), and one soil site in an industrial area, S-Ind-Soil (Figure 2); in both ΣHCH was the highest. In general, the concentration of OCP classes decreased as follows: ΣDDT>ΣHCH>Σendosulfan>dicofol. The levels of OCP within the classes varied between sites as described in the next section.

\* *o,p'*-DDT + *p,p'-*DDD + *p,p'*-DDT + *p,p'*-DDE, # α,γ HCH, ^ α,β,γ,δ-HCH, a I-Endosulfan + II-Endosulfan, NM: not measured, SA: South Africa

Table 3. Mean OCP levels (ng g-1) as reported in other international studies.

#### **7.3 HCH**

γ-HCH, better known as lindane, was one of the most widely used pesticides in the world. However, on 9 May 2009 lindane was added to Annex A (chemicals cited for elimination) of the Stockholm Convention. Lindane was commonly used in the treatment of seed, livestock and as a household biocide (Osibanjo et al., 2002). Although relatively little literature has been published on the use and production of these chemicals in South Africa, it is known that HCH was produced until the early 1980s at a site in Kempton Park (Osibanjo et al., 2002). Kempton Park is situated approximately 80 km northeast of the Vaal Triangle. The main wind direction for that area is north and north-northwest, which could have contributed to dispersing lindane to the Vaal Triangle in the past. However, lindane is currently registered and used in the agricultural of cotton, maize and wheat crops, amongst others, as well as in domestic gardens (Nel et al., 2002, Table 1). It would be interesting to track possible changes in soil and sediment levels following eventual de-registration.

Fig. 2. Distribution patterns of different OCPs between sites

The ΣHCH concentration in soil varied between 0.17 - 1.86 ng g-1 with the highest concentration measured at Sasolburg (S-Ind-Soil) in soil collected close to the petrochemical plant. The lowest level was measured in the low-income residential area in Vanderbijlpark (Vdb-Inf-Soil). In sediment, the concentration varied between 0.3 - 1.7 ng g-1, with the highest concentration measured in the predominantly agricultural area of the Orange River (OrangeRiv). The values for HCH are in the same order of magnitude as determined in other studies (Table 3).

Lindane consists of a mixture of all HCH isomers with approximately 90% γ-HCH (Wang et al., 2007). In technical HCH, the isomer ratio is different with α-HCH representing 55 – 80% of the total mixture (Gong et al., 2007). In both soil and sediments, γ-HCH was the most prevalent with more than 80% contribution to ΣHCH levels (Table 4), followed by β-HCH and α-HCH. This points to recent use of lindane rather than technical HCH or historic inputs, since γ-HCH is degraded more rapidly than α-HCH both under aerobic and anaerobic conditions (Wu et al., 1997).

Table 4. Summary of mean HCH values and percentage contribution of each isomer for soil and sediment

#### **7.4 DDT and dicofol**

82 Pesticides in the Modern World – Pesticides Use and Management

The lowest OCP levels for the South African study were measured in the Taaibos Spruit (TbosSpr), which receives run-off impacted by low-income residential areas as well as petrochemical industries. The OCP levels for sites primarily influenced by agricultural activities ranged between 2.3 - 0.59 ng/g (Figure 2). Of the four classes of OCPs (ΣDDT, dicofol, ΣHCH and Σendosulfan), ΣDDT was the highest at all sites, except for one sediment site in an agricultural area (OrangeRiv), and one soil site in an industrial area, S-Ind-Soil (Figure 2); in both ΣHCH was the highest. In general, the concentration of OCP classes decreased as follows: ΣDDT>ΣHCH>Σendosulfan>dicofol. The levels of OCP within the

Σ

Canada Mixed Sediment 7 0.36 0.03# 6.8 Wong et al., 2009

Canada Mixed Soil 7 0.13 0.04# 68 Wong et al., 2009

China Fallow Soil 14^ 25 Wang et al., 2007

Brazil Agricultural Soil 29 0.52 0.1 1.4\* Rissato et al., 2006

Morocco Agricultural Soil 5 1.5 0.02 0.03\* Bakouri et al., 2008

Uganda Mixed Soil 8 0.4 NM 0.3 Ssebugere et al.,

SA Industrial Soil 4 0.09 0.70 3.5 Present study

SA Mixed Sediment 9 0.05 0.52 1.7 Present study \* *o,p'*-DDT + *p,p'-*DDD + *p,p'*-DDT + *p,p'*-DDE, # α,γ HCH, ^ α,β,γ,δ-HCH, a I-Endosulfan + II-

γ-HCH, better known as lindane, was one of the most widely used pesticides in the world. However, on 9 May 2009 lindane was added to Annex A (chemicals cited for elimination) of the Stockholm Convention. Lindane was commonly used in the treatment of seed, livestock and as a household biocide (Osibanjo et al., 2002). Although relatively little literature has been published on the use and production of these chemicals in South Africa, it is known that HCH was produced until the early 1980s at a site in Kempton Park (Osibanjo et al., 2002). Kempton Park is situated approximately 80 km northeast of the Vaal Triangle. The main wind direction for that area is north and north-northwest, which could have contributed to dispersing lindane to the Vaal Triangle in the past. However, lindane is currently registered and used in the agricultural of cotton, maize and wheat crops, amongst others, as well as in domestic gardens (Nel et al., 2002, Table 1). It would be interesting to

track possible changes in soil and sediment levels following eventual de-registration.

Table 3. Mean OCP levels (ng g-1) as reported in other international studies.

**Endosulfan** <sup>Σ</sup> **HCH** <sup>Σ</sup> **DDT Reference**

2010

classes varied between sites as described in the next section.

**samples**

**Country Land use Matrix <sup>N</sup>**

Endosulfan, NM: not measured, SA: South Africa

**7.3 HCH**

DDT, in use since the Second World War, was the first internationally used pesticide due to its highly effective insecticidal properties and ease of manufacture (Stenersen, 2004). DDT is often found in the environment even in areas where it is not currently applied due to its highly persistent nature and ability to be passively (wind and water) and actively (through biota)

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 85

(Kumar et al., 2008), can moderately adsorb to soil, and is metabolised to endosulfan-sulfate, endosulfandiol and endsulfan ether, amongst other breakdown products. Endosulfan-I is the least persistent with a half-life of 35 days (Osibanjo et al., 2002) in contrast to endosulfan-II and endosulfan-sulfate, which may persist for years, depending on environmental conditions. Endosulfan is currently registered in South Africa for a wide variety of crops

Levels of endosulfan were low in all samples, ranging between 0.03 and 0.18 ng g-1. The highest values measured were in S-Ind-Soil (0.18 ng g-1) and in the sediment of the Orange River (OrangeRiv) (0.12 ng g-1). The mean concentration of endosulfan in soil and sediment was very similar (Table 6). Percentage contributions show the predominance of endosulfan-I when compared to endosulfan-II and endosulfan-sulfate (Table 6). This would usually indicate the current use of endosulfan. However, the low levels of this pesticide detected,

> Concentration range ΣEndosulfan

Soil 4 0.09 0.03 – 0.18 61 21 18 Sediment 9 0.05 0.03 – 0.12 47 26 26

Table 6. Summary of mean Σendosulfan values and compound ratio's for soil and sediment

Due to the restricted sample size, it was not possible to draw definitive conclusions from the PCA. However, the available data did shed some light on patterns in the data sets. In the PCA, factor 1 explained 40%, factor 2, 30% and factor 3, 16% of the variance in the data. The greatest contributors to factor 1 were endosulfan-I, γHCH and α-HCH on the positive side and *p,p'*  DDE on the negative side (Figure 3). Factor 1 therefore contrasts OCPs still in use with DDT that is not in use in the study area. There is no clear clustering of sampled sites because of factor 1. Factor 2 is formed by a contrast between DDT isomers: *o,p'*-DDT and *p,p'*-DDT on the positive side and *p,p'*-DDD and *p,p'*-DDD on the negative side. This factor seems to have influenced the distribution of the sites on the biplot roughly into soil sites (on the positive side of factor 2) and the sediment sites on the negative side of factor 2 (Figure 3). Factor 3 consists of a contrast between DDT and its DDD metabolites on the positive side and the metabolites and isomers of endosulfan, *o,p'*-DDE and dicofol on the negative side. It is when factor 2 and 3 are plotted together that the clustering effect of the sites due to factor 2 is clearly observed (Figure 4). In a previous investigation by Nieuwoudt et al (2009) in the same sampling area, the distinction between soil and sediment concentrations was also made for dioxin-like chemicals. In summary, the pesticide residues measured in both soil and sediment in this study were generally low, with values ranging from below the detection limit to 6.6 ng g-1. The highest concentrations found did not coincide with agricultural land use, but with industry (Vnd-Ind-Soil). This site consisted of mainly industrial and residential areas in Vanderbijlpark. A PCA of the data showed a separation between sediment and soil profiles of the OCPs. Although agricultural use of DDT has been banned in South Africa since 1983, measurable levels were found in soil and sediment in areas outside the endemic malaria area where it is still sprayed.

%Endosulfan I

%Endosulfan II

%Endosulfan -sulfate

(Nel et al., 2002; Table 1).

Matrix Nr of

samples

**7.6 Principle component analysis**

makes it difficult to draw any clear-cut conclusions.

Mean concentration of ΣEndosulfan

transported. The current study area falls outside the endemic malaria regions of South Africa (Figure 1), the closest of which is 700 km away. As expected, the ΣDDT levels measured were relatively low, varying between 0.3 - 6.7 ng g-1, with the highest values measured in Vnd-Inf-Soil. The ΣDDT levels measured in soil were compared to those measured in sediment. The data was not normally distributed (p = 0.03, Shapiro-Wilk test) and the relationship was tested with the non-parametric Mann-Whitney U test. Although the levels in soil were higher than those in sediment, this difference was not statistically significant (p = 0.24).

To assess when DDT was applied, the ratio of DDT/(DDE + DDD) was calculated. Values greater than one indicate recent applications, while values lower than one indicate historic use (Chen et al., 2005; Gong et al., 2007). The mean ratios were lower than 0.5 (Table 5) with the exception of S-Ind-Soil that had a ratio of 1.1. The mean ratio was also less in sediment than in soil. The ratio of *o,p*'-DDT to *p,p*'-DDT distinguishes between pollution caused by technical DDTs and pollution from other sources such as dicofol. (Fu et al., 2009). Since *o,p*'- DDT is less stable, it is expected to be less prevalent in the environment. Dicofol would produce a higher *o,p'*-DDT to *p,p'*-DDT ratio since there is generally more *o,p'*-DDT in dicofol than *p,p'*-DDT (Qiu et al., 2005). The ratio in this study was 0.24 for soil and 0.58 for sediment (Table 5). These values indicate that the DDT pollution detected is more likely from the use of technical DDT.

Table 5. Summary of mean DDT values and metabolite ratio's for soil and sediment

Once applied, DDT degrades to DDD and DDE. Degradation to DDD is through reductive dechlorination, while degradation to DDE is through dehydrochlorination processes (Wang et al., 2007). The ratio of DDE/DDD at all sites was greater than one. This indicates that the majority of DDT is degraded to DDE in both matrices, with the DDD levels playing a larger role in sediment than soil due to anaerobic conditions. This may show that a larger portion of DDT is degraded through reductive dechlorination in sediment than in soil.

Dicofol is a non-systemic acaricide used in the control of mites on numerous crops including cotton citrus and other fruit (Clark et al., 1990; Qiu et al., 2005). Dicofol is registered for use in South Africa, mainly for cultivation of fruit and garden use (Nel et al., 2002; Table 1). Due to the process of dicofol synthesis, it is often contaminated with DDT. Dicofol levels were low in all samples analysed, with soil and sediment levels in the same range. The highest dicofol level (0.06 ng g-1) was measured for Vnd-Ind-Soil. Considered together with the calculated DDT/(DDD + DDE) ratios (table 3), again indicates DDT rather than dicofol as source of the DDT breakdown products measured in soils and sediment.

#### **7.5 Endosulfan**

Endosulfan, a cyclodiene insecticide, is widely used in agricultural applications as both an insecticide and acaricide (Osibanjo et al., 2002). Endosulfan is a wide spectrum contact insecticide (Capkin et al., 2006) that consists of a mixture of endosulfan-I and II isomers (Kumar et al., 2008), can moderately adsorb to soil, and is metabolised to endosulfan-sulfate, endosulfandiol and endsulfan ether, amongst other breakdown products. Endosulfan-I is the least persistent with a half-life of 35 days (Osibanjo et al., 2002) in contrast to endosulfan-II and endosulfan-sulfate, which may persist for years, depending on environmental conditions. Endosulfan is currently registered in South Africa for a wide variety of crops (Nel et al., 2002; Table 1).

Levels of endosulfan were low in all samples, ranging between 0.03 and 0.18 ng g-1. The highest values measured were in S-Ind-Soil (0.18 ng g-1) and in the sediment of the Orange River (OrangeRiv) (0.12 ng g-1). The mean concentration of endosulfan in soil and sediment was very similar (Table 6). Percentage contributions show the predominance of endosulfan-I when compared to endosulfan-II and endosulfan-sulfate (Table 6). This would usually indicate the current use of endosulfan. However, the low levels of this pesticide detected, makes it difficult to draw any clear-cut conclusions.

Table 6. Summary of mean Σendosulfan values and compound ratio's for soil and sediment

#### **7.6 Principle component analysis**

84 Pesticides in the Modern World – Pesticides Use and Management

transported. The current study area falls outside the endemic malaria regions of South Africa (Figure 1), the closest of which is 700 km away. As expected, the ΣDDT levels measured were relatively low, varying between 0.3 - 6.7 ng g-1, with the highest values measured in Vnd-Inf-Soil. The ΣDDT levels measured in soil were compared to those measured in sediment. The data was not normally distributed (p = 0.03, Shapiro-Wilk test) and the relationship was tested with the non-parametric Mann-Whitney U test. Although the levels in soil were higher than

To assess when DDT was applied, the ratio of DDT/(DDE + DDD) was calculated. Values greater than one indicate recent applications, while values lower than one indicate historic use (Chen et al., 2005; Gong et al., 2007). The mean ratios were lower than 0.5 (Table 5) with the exception of S-Ind-Soil that had a ratio of 1.1. The mean ratio was also less in sediment than in soil. The ratio of *o,p*'-DDT to *p,p*'-DDT distinguishes between pollution caused by technical DDTs and pollution from other sources such as dicofol. (Fu et al., 2009). Since *o,p*'- DDT is less stable, it is expected to be less prevalent in the environment. Dicofol would produce a higher *o,p'*-DDT to *p,p'*-DDT ratio since there is generally more *o,p'*-DDT in dicofol than *p,p'*-DDT (Qiu et al., 2005). The ratio in this study was 0.24 for soil and 0.58 for sediment (Table 5). These values indicate that the DDT pollution detected is more likely

> Concentration range ΣDDT (ng g-1)

Table 5. Summary of mean DDT values and metabolite ratio's for soil and sediment

of DDT is degraded through reductive dechlorination in sediment than in soil.

source of the DDT breakdown products measured in soils and sediment.

Soil 4 3.5 0.5 – 6.7 0.42 120 0.24 Sediment 9 1.7 0.3 – 4.6 0.07 16 0.58

Once applied, DDT degrades to DDD and DDE. Degradation to DDD is through reductive dechlorination, while degradation to DDE is through dehydrochlorination processes (Wang et al., 2007). The ratio of DDE/DDD at all sites was greater than one. This indicates that the majority of DDT is degraded to DDE in both matrices, with the DDD levels playing a larger role in sediment than soil due to anaerobic conditions. This may show that a larger portion

Dicofol is a non-systemic acaricide used in the control of mites on numerous crops including cotton citrus and other fruit (Clark et al., 1990; Qiu et al., 2005). Dicofol is registered for use in South Africa, mainly for cultivation of fruit and garden use (Nel et al., 2002; Table 1). Due to the process of dicofol synthesis, it is often contaminated with DDT. Dicofol levels were low in all samples analysed, with soil and sediment levels in the same range. The highest dicofol level (0.06 ng g-1) was measured for Vnd-Ind-Soil. Considered together with the calculated DDT/(DDD + DDE) ratios (table 3), again indicates DDT rather than dicofol as

Endosulfan, a cyclodiene insecticide, is widely used in agricultural applications as both an insecticide and acaricide (Osibanjo et al., 2002). Endosulfan is a wide spectrum contact insecticide (Capkin et al., 2006) that consists of a mixture of endosulfan-I and II isomers

Mean ratio of DDT to DDT metabolites

Mean ratio of DDE to DDD

Mean ratio of *o,p'*DDT to *p,p'*DDT

those in sediment, this difference was not statistically significant (p = 0.24).

from the use of technical DDT.

samples

Mean ΣDDT (ng g-1)

Matrix Nr of

**7.5 Endosulfan**

Due to the restricted sample size, it was not possible to draw definitive conclusions from the PCA. However, the available data did shed some light on patterns in the data sets. In the PCA, factor 1 explained 40%, factor 2, 30% and factor 3, 16% of the variance in the data. The greatest contributors to factor 1 were endosulfan-I, γHCH and α-HCH on the positive side and *p,p'*  DDE on the negative side (Figure 3). Factor 1 therefore contrasts OCPs still in use with DDT that is not in use in the study area. There is no clear clustering of sampled sites because of factor 1. Factor 2 is formed by a contrast between DDT isomers: *o,p'*-DDT and *p,p'*-DDT on the positive side and *p,p'*-DDD and *p,p'*-DDD on the negative side. This factor seems to have influenced the distribution of the sites on the biplot roughly into soil sites (on the positive side of factor 2) and the sediment sites on the negative side of factor 2 (Figure 3). Factor 3 consists of a contrast between DDT and its DDD metabolites on the positive side and the metabolites and isomers of endosulfan, *o,p'*-DDE and dicofol on the negative side. It is when factor 2 and 3 are plotted together that the clustering effect of the sites due to factor 2 is clearly observed (Figure 4). In a previous investigation by Nieuwoudt et al (2009) in the same sampling area, the distinction between soil and sediment concentrations was also made for dioxin-like chemicals. In summary, the pesticide residues measured in both soil and sediment in this study were generally low, with values ranging from below the detection limit to 6.6 ng g-1. The highest concentrations found did not coincide with agricultural land use, but with industry (Vnd-Ind-Soil). This site consisted of mainly industrial and residential areas in Vanderbijlpark. A PCA of the data showed a separation between sediment and soil profiles of the OCPs. Although agricultural use of DDT has been banned in South Africa since 1983, measurable levels were found in soil and sediment in areas outside the endemic malaria area where it is still sprayed.

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa 87

Fig. 4. A PCA bi-plot of factor 2 and factor 3, including all OCP data. Sites are indicated with

Pesticide use is an integral part of every-day South African's life. It does not only impact populations at risk from malaria, but also the farmer, consumer, exporter and end-user of natural resources such as water. Therefore, the use of pesticides must be regarded as a serious management issue and not only at farm level, but, also at government level. Although pesticide research is well founded in South Africa, limitations exist within laboratory frameworks. Although pesticides have been detected in almost all conceivable media, there is still a lack of knowledge of background levels. These levels are needed to make realistic impact and health assessments when studying highly impacted areas. The serious health risks associated with certain pesticides are not only for occupational exposure, but also for end-user exposure. MRLs have been established to protect both the importer as well as the consumer. Table 1 indicates that South African MRLs are within the same range as those listed for the EU on the EU pesticide database (EU, 2010b). This ensures continued trade as well as protecting the health of the South African citizen. Aspects not specifically raised in this text that should be kept in mind within the South African context include the occurrence of accidental poisoning cases among farm workers as well as children. This occurs easily when the user did not receive proper training and does not understand how to use the pesticide. This is specifically a problem in areas with low literacy. There is also the question of obsolete pesticide stockpiles that can leach into the environment and have disastrous effects on ground water. These are challenges unique to developing economies, rarely seen in developed countries and should be considered in the international decision making process regarding the use and import of pesticides. In conclusion; although the need and usefulness of pesticides cannot be denied, the advantages of introducing these chemicals into the environment needs to be weighed against the possible negative side

a square and compounds with a triangle.

**8. Conclusions and parting thoughts**

The reasons for the differences between soils and sediment profiles and levels indicates the need for further studies, while exposure and accumulation in humans and biota needs scrutiny even at these low levels. A previous study by Bouwman et al (2008) found measurable levels of OCPs in wild bird eggs, including DDT and its metabolites as well as HCH. These levels (ΣDDT: 1.48 – 300 ng g-1 ww) were also higher than what can be expected from the low levels measured in sediment and soil here (ΣDDT: 0.02 – 6.7 ng g-1dw). Although these interactions are influenced by other factors such as diet, bio-accumulation and collection area, they all play a crucial part. Very little is known about these aspects under African and South African conditions. This pilot study indicated that knowledge concerning background levels of pesticides is important. If background levels are not investigated, patterns of pesticide occurrence and distribution would be missed.

Fig. 3. A PCA bi-plot of factor 1 and factor 2, including all OCP data. Sites are indicated with a square and compounds with a triangle.

The reasons for the differences between soils and sediment profiles and levels indicates the need for further studies, while exposure and accumulation in humans and biota needs scrutiny even at these low levels. A previous study by Bouwman et al (2008) found measurable levels of OCPs in wild bird eggs, including DDT and its metabolites as well as HCH. These levels (ΣDDT: 1.48 – 300 ng g-1 ww) were also higher than what can be expected from the low levels measured in sediment and soil here (ΣDDT: 0.02 – 6.7 ng g-1dw). Although these interactions are influenced by other factors such as diet, bio-accumulation and collection area, they all play a crucial part. Very little is known about these aspects under African and South African conditions. This pilot study indicated that knowledge concerning background levels of pesticides is important. If background levels are not

Fig. 3. A PCA bi-plot of factor 1 and factor 2, including all OCP data. Sites are indicated with

a square and compounds with a triangle.

investigated, patterns of pesticide occurrence and distribution would be missed.

Fig. 4. A PCA bi-plot of factor 2 and factor 3, including all OCP data. Sites are indicated with a square and compounds with a triangle.

#### **8. Conclusions and parting thoughts**

Pesticide use is an integral part of every-day South African's life. It does not only impact populations at risk from malaria, but also the farmer, consumer, exporter and end-user of natural resources such as water. Therefore, the use of pesticides must be regarded as a serious management issue and not only at farm level, but, also at government level. Although pesticide research is well founded in South Africa, limitations exist within laboratory frameworks. Although pesticides have been detected in almost all conceivable media, there is still a lack of knowledge of background levels. These levels are needed to make realistic impact and health assessments when studying highly impacted areas. The serious health risks associated with certain pesticides are not only for occupational exposure, but also for end-user exposure. MRLs have been established to protect both the importer as well as the consumer. Table 1 indicates that South African MRLs are within the same range as those listed for the EU on the EU pesticide database (EU, 2010b). This ensures continued trade as well as protecting the health of the South African citizen. Aspects not specifically raised in this text that should be kept in mind within the South African context include the occurrence of accidental poisoning cases among farm workers as well as children. This occurs easily when the user did not receive proper training and does not understand how to use the pesticide. This is specifically a problem in areas with low literacy. There is also the question of obsolete pesticide stockpiles that can leach into the environment and have disastrous effects on ground water. These are challenges unique to developing economies, rarely seen in developed countries and should be considered in the international decision making process regarding the use and import of pesticides. In conclusion; although the need and usefulness of pesticides cannot be denied, the advantages of introducing these chemicals into the environment needs to be weighed against the possible negative side

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