**Suggested citation:** EFSA (European Food Safety Authority) , 2018 Statement on non‐dietary exposure on diquat. EFSA Journal 2018;16(5):5260, 15 pp. 10.2903/j.efsa.2018.5260

**Requestor:** European Commission

**Question number:** EFSA‐Q‐2018‐00228

Adopted: 13 April 2018

1. Introduction {#efs25260-sec-0002}
===============

1.1. Background and Terms of Reference as provided by the requestor {#efs25260-sec-0003}
-------------------------------------------------------------------

**Background information**

Diquat is a substance covered by the second stage of the renewal programme ('AIR2') in accordance with Regulation (EC) No 1141/2010[1](#efs25260-note-1101){ref-type="fn"}.

An application for renewal of diquat was submitted by Syngenta Crop Protection AG and Sharda Cropchem Ltd (former Sharda Worldwide Exports Pvt. Ltd) to the rapporteur Member State (RMS), the United Kingdom, and to the co‐rapporteur Member State (co‐RMS), Sweden.

Following the submission of the Renewal Assessment Report (RAR) to the European Food Safety Authority (EFSA) by the RMS (United Kingdom), which was received on 19 September 2014, EFSA initiated the peer review of the RAR in line with the provisions of Regulation (EC) No 1141/2010. Following the completion of the peer review, including expert consultation in the areas of mammalian toxicology, residues and ecotoxicology, EFSA published its conclusion on the pesticide peer review for diquat on 12 November 2015 (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}).

The European Commission consulted the applicants on the EFSA Conclusion and the draft review report prepared by the Commission. Comments were received from both applicants. The applicant Syngenta Crop Protection AG also contacted EFSA directly. Following the comments received, a discussion took place between EFSA and Syngenta Crop Protection AG which was of a technical nature and mainly focussed on the selection of input parameters for the non‐dietary exposure assessment.

This technical discussion was concluded with a letter sent from EFSA to Syngenta Crop Protection AG on 23 November 2017 proposing that the European Commission might consider the need to re‐assess the non‐dietary exposure to diquat as outlined in that letter. This letter repeated a summary provided by EFSA to the Commission on 21 September 2017.

By means of the mandate received on 6 March 2018 from the European Commission, EFSA was requested to update the non‐dietary exposure assessment and provide a statement by 13 April 2018. Based on that mandate, EFSA prepared a draft statement in March 2018 which was circulated to all Member States for commenting via a written procedure. On the basis of the comments received, it was deemed necessary to conduct an expert consultation in the area of mammalian toxicology with experts on non‐dietary exposure assessment, before EFSA finalises the statement. Therefore, the non‐dietary exposure assessment of diquat was discussed at the pesticides peer review experts' teleconference 177 on 23 March 2018. The conclusions of this meeting were considered by EFSA during the finalisation of the statement.

The overview of the non‐dietary exposure estimates for diquat, the application parameters and the detailed calculations are presented in the Appendices [Appendix A -- Overview of non‐dietary exposure estimates to diquat in Reglone (A1412A)](#efs25260-sec-1001){ref-type="sec"}, [Appendix B -- Overview of non‐dietary exposure estimates to diquat in Diquat 20% SL](#efs25260-sec-1002){ref-type="sec"}, [Appendix C -- Application parameters for the representative PPPs](#efs25260-sec-1003){ref-type="sec"}, [Appendix D -- Detailed calculations. Reglone (A1412A)](#efs25260-sec-1004){ref-type="sec"}, [Appendix E -- Detailed calculations. Diquat 20%SL](#efs25260-sec-1005){ref-type="sec"}--[E](#efs25260-sec-1005){ref-type="sec"} of this statement. A key supporting document to this statement is the peer review report (EFSA, [2018](#efs25260-bib-0004){ref-type="ref"}), which is a compilation of all the documents developed during the evaluation and the assessment requested in the mandate. The peer review report comprises the following documents, in which all views expressed during the process, including minority views, where applicable, can be found: the comments received on the draft statement;the report of the scientific consultation with Member State experts

Given the importance of the peer review report, this document is considered as background document to this statement and thus is made publicly available.

**Terms of Reference**

EFSA was mandated by the European Commission to update the non‐dietary exposure assessment of diquat (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}) and provide a statement that takes into account the following: detailed calculations for other uses than the critical Good Agricultural Practice (GAP) (potatoes);calculations of the exposure of bystanders and residents on the basis of the EFSA calculator including refinement for bystander and resident exposure to 'vapour' scenario using the saturated vapour concentration (SVC) approach (HEEG opinion 13 (European Commission, [2011](#efs25260-bib-0005){ref-type="ref"}));applying the German approach without modification;consideration of whether re‐entry worker exposure is needed or not for the critical GAP (potatoes) and other uses.

**Interpretation of the Terms of Reference**

The non‐dietary exposure assessment on diquat includes uses which were supported by Syngenta Crop Protection AG and Sharda Cropchem Ltd. The representative formulations are Reglone (A1412A) and Diquat 20% SL, respectively. Both Reglone (A1412A) and Diquat 20% SL are soluble‐concentrate (SL) formulations containing 200 g/L diquat. The representative uses include desiccant, weed control and pre‐emergence weed control, with different application rates. The RMS calculated exposure estimates for the critical GAPs (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}).

The current assessment has considered representative uses for Reglone (A1412A) and Diquat 20% SL, the different exposure groups and the critical and less‐critical GAPs. The EFSA calculator has been used only for the calculations of the exposure for bystanders and residents as requested by the European Commission.

This document is not a stand‐alone document and should be read alongside other supporting documents including the EFSA conclusion (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}), the peer review report (EFSA, [2015b](#efs25260-bib-0003){ref-type="ref"}) and the RAR (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}) since further description is given by the RMS in the RAR regarding the models and approaches agreed during the peer review.

2. Assessment {#efs25260-sec-0004}
=============

The input parameters as agreed during the peer review process and relevant for non‐dietary exposure (extracted from the List of Endpoints, EFSA [2015a](#efs25260-bib-0002){ref-type="ref"}) are presented in Table [1](#efs25260-tbl-0001){ref-type="table"}. These input parameters have been used in the current assessment.

###### 

Input parameters for non‐dietary exposure (extracted from the List of Endpoints, EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"},[b](#efs25260-bib-0003){ref-type="ref"})

+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| Vapour pressure                                  | Syngenta Crop Protection AG: maximum limit \< 10^−5^ Pa                                                           |
|                                                  |                                                                                                                   |
|                                                  | Sharda Cropchem Ltd: maximum limit \< 4 × 10^−6^ Pa[a](#efs25260-note-0005){ref-type="fn"} at 25°C (diquat ≥ 98%) |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| Molecular mass of the cation                     | 184.2 g/mol                                                                                                       |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| Oral absorption                                  | 4%                                                                                                                |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| AOEL                                             | 0.0002 mg/kg bw per day                                                                                           |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| Dermal absorption of diquat in Reglone (A1412A): | Concentrate: 0.5%                                                                                                 |
|                                                  |                                                                                                                   |
|                                                  | 1 + 100 dilution: 0.5%                                                                                            |
|                                                  |                                                                                                                   |
|                                                  | 1 + 200 dilution: 2%                                                                                              |
|                                                  |                                                                                                                   |
|                                                  | Human *in vitro* data                                                                                             |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+
| Dermal absorption of diquat in Diquat 20% SL:    | Concentrate: 0.2%                                                                                                 |
|                                                  |                                                                                                                   |
|                                                  | 1 + 250 dilution: 8%                                                                                              |
|                                                  |                                                                                                                   |
|                                                  | Human *in vitro* data                                                                                             |
+--------------------------------------------------+-------------------------------------------------------------------------------------------------------------------+

AOEL: acceptable operator exposure level; bw: body weight.

This value has been used to calculate the saturated vapour concentration.

John Wiley & Sons, Ltd

2.1. Representative uses for Reglone (A1412A) {#efs25260-sec-0005}
---------------------------------------------

The non‐dietary exposure estimates presented in the RAR (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}) were based on the original dermal absorption value of 0.5% for the in‐use Reglone (A1412A) dilution and were not updated during the peer review with the higher dermal absorption value of 2% for the 1/200 Reglone (A1412A) dilution as agreed during the peer review (see Table [1](#efs25260-tbl-0001){ref-type="table"}). This was considered appropriate as there was already exceedance of the acceptable operator exposure level (AOEL) with a lower dermal absorption value. Dermal absorption value of 2% for the 1/200 Reglone (A1412A) dilution has been used for the updated calculation of bystanders, residents and workers exposure under the current assessment.

The EFSA conclusion (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}) included the exposure estimates for the critical GAP (i.e. desiccant in potatoes). These estimates were covering other uses with a lower application rate. For the current assessment, the use as a desiccant in oilseed rape has been selected as the less‐critical GAP in terms of lower application rate than desiccant in potato.

An overview table summarising the outcome of the non‐dietary exposure assessment of diquat in Reglone (A1412A) is included in Appendix [A](#efs25260-sec-1001){ref-type="sec"}. The results are discussed below.

### 2.1.1. Operator exposure to diquat in Reglone (A1412A) {#efs25260-sec-0006}

#### 2.1.1.1. Critical GAP {#efs25260-sec-0007}

The critical GAP is desiccant in potatoes up to maximum application rate of 1 kg a.s./ha. A higher tier exposure field study was available (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}) covering a maximum application rate of 0.8 kg a.s./ha; therefore, the operator exposure estimates covered representative uses up to 0.8 kg a.s./ha. The resulting exposure estimates indicated a non‐exceedance of the AOEL under the conditions of the field study (i.e. coveralls and gloves during mixing/loading, maintenance work and application and tractor fitted with closed cabin).

#### 2.1.1.2. Other uses than the critical GAP {#efs25260-sec-0008}

The higher tier exposure field study for potato (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}) covered other uses than the critical GAP (i.e. oilseed rape, apples and tomato). Exposure estimates indicated non‐exceedance of the AOEL under the conditions of the field study (i.e. coveralls and gloves during mixing/loading, maintenance work and application and tractor fitted with closed cabin).

### 2.1.2. Bystander and resident exposure to diquat in Reglone (A1412A) {#efs25260-sec-0009}

Bystander and resident exposure to diquat in Reglone (A1412A) was calculated following the agreed approach during the peer review on diquat. As requested by the European Commission the original German approach and the EFSA calculator including also the SVC approach are also presented under Sections [2.1.2.1](#efs25260-sec-0010){ref-type="sec"} and [2.1.2.1](#efs25260-sec-0011){ref-type="sec"}. The outcome of the different approaches was further discussed during the pesticides peer review experts' teleconference 177 as presented in Section [3.1](#efs25260-sec-0026){ref-type="sec"}.

#### 2.1.2.1. Critical GAP {#efs25260-sec-0010}

*Approach followed during the AIR II peer review on diquat*

For bystander and resident exposure, the approach followed during the peer review of diquat (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"},[b](#efs25260-bib-0003){ref-type="ref"}) included the [UK approach]{.ul}, [German approach]{.ul} and [re‐entry of general public]{.ul} (entry into treated crops for bystander and resident).

The RMS considered exposure to a default vapour concentration of 0.001 mg/m^3^ vapour in both, the UK and the German approach. This was agreed during the peer review on diquat (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"},[b](#efs25260-bib-0003){ref-type="ref"}).

Several buffer distances can be considered for bystander and resident and some of them were already used during the peer review for the UK and the German approach. Additional distances are also included for the German approach (10 and 5 m) to update the assessment.

The calculations, as presented in the RAR (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}) and referred into the EFSA conclusion (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}), were performed with an oral absorption value of 100%, whereas the agreed oral absorption value during the peer review was 4% (see Table [1](#efs25260-tbl-0001){ref-type="table"}). This input parameter could be used as a refinement for bystander and resident exposure (UK approach for exposure to fallout and German approach for resident child). The current assessment considered oral absorption of 4% for bystander and resident.

Exposure estimates to diquat following the [UK approach]{.ul}, [German approach]{.ul} and [re‐entry of general public]{.ul} indicated an exceedance of the AOEL for the critical GAP (i.e. desiccant in potatoes).

*German approach without exposure to vapour*

The original German approach refers to the publication by Martin et al. ([2008](#efs25260-bib-0007){ref-type="ref"}). It is noted that according to that publication no exposure to airborne concentration should be taken into account for substances with a low vapour pressure such as diquat. Buffer distances of 1, 5 and 10 m were considered.

Exposure estimates to diquat based on the original German approach indicated exceedance of the AOEL for bystanders and residents located at 1 m but not at 5 or 10 m.

*Bystander and resident exposure according to the EFSA calculator including also the saturated vapour concentration approach*

Exposure estimates to diquat for the critical GAP were not calculated during this updated assessment since exposure estimates for other uses than the critical GAP already indicated exceedance of the AOEL (see Section [2.1.2.2](#efs25260-sec-0011){ref-type="sec"}).

#### 2.1.2.2. Other uses than the critical GAP {#efs25260-sec-0011}

*Approach followed during the AIR II peer review on diquat*

Following the same approach as described for the critical GAP (see Section [2.1.2.2](#efs25260-sec-0011){ref-type="sec"}), bystander and resident exposure estimates to diquat for the use in oilseed rape (GAP with the lower application rate, i.e. 0.6 kg a.s./ha) were above the AOEL (UK approach, German approach and re‐entry of general public).

*German approach without exposure to vapour*

No calculations have been done since the exposure estimates for the critical GAP (with a higher application rate) covered other uses than the critical GAP (with a lower application rate). The same conclusion applies, i.e. exposure estimates to diquat indicated exceedance of the AOEL for bystanders and residents located at 1 m but not at 5 or 10 m).

*Bystanders and residents exposure according to the EFSA calculator including also the saturated vapour concentration approach*

Bystander and resident exposure according to the EFSA model (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}) has been calculated considering a 10 m buffer distance, oral absorption of 4% and vehicle‐mounted‐drift reduction. A refinement using a SVC approach (European Commission, [2011](#efs25260-bib-0005){ref-type="ref"}) was also included in the calculations using input parameters described in Table [1](#efs25260-tbl-0001){ref-type="table"} (the vapour pressure of 4 × 10^−6^ Pa has been used in the calculations).

According to the HEEG opinion (European Commission, [2011](#efs25260-bib-0005){ref-type="ref"}), the SVC is equal to 0.41 × Molecular Weight × Vapour Pressure (mg/m^3^). Taking into account input parameters in Table [1](#efs25260-tbl-0001){ref-type="table"}, the SVC of diquat would be 0.0003 mg/m^3^.

Exposure calculation for a child (bystander and resident) to diquat via [spray drift]{.ul} showed an exceedance of the AOEL, whereas for an adult (bystander and resident) the exposure calculation showed no exceedance of the AOEL.

Bystander and resident exposure calculations for default [vapour]{.ul} concentration of 0.001 mg/m^3^ showed exceedance of the AOEL for both child and adult. Bystander and resident exposure for SVC showed exceedance of the AOEL for the child, whereas no exceedance is shown for adult.

Bystander and resident exposure to [surface deposits]{.ul} showed no exceedance of the AOEL.

Exposure estimates for the [entry into treated crops]{.ul} for bystander and resident (child and adult) showed an exceedance of the AOEL.

### 2.1.3. Worker exposure to diquat in Reglone (A1412A) {#efs25260-sec-0012}

#### 2.1.3.1. Critical GAP {#efs25260-sec-0013}

*Approach followed during the AIR II peer review on diquat*

The RMS considered that only for the use as a desiccant on potatoes there was a need for re‐entry into the treated crop (i.e. inspection). The quantitative assessment done for re‐entry exposure assessment in potato indicated an exceedance of the AOEL.

*Approach discussed during the pesticides peer review experts' teleconference 177*

The RMS clarified that the considerations followed during the peer review of diquat were based on the context of the original assessment that provided a result within the AOEL originally proposed by the RMS and the potential for exposure from the use on other crops was considered initially relatively insignificant (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}). As the peer review conclusion adopted a lower AOEL and higher dermal absorption values, it was deemed appropriate to consider potential for exposure from the use on other crops.

During the pesticides peer review experts' teleconference 177, the RMS confirmed that for desiccant uses on potato there is a need for crop inspection. Inspection is needed to check if the treatment was efficient. A default transfer coefficient (TC) of 2,500 cm^2^/h × person (van Hemmen et al., [2002](#efs25260-bib-0006){ref-type="ref"}) and 2 h for inspection were initially used in the calculations. The RMS commented that 2 h could be considered too long for this activity. However, a reliable shorter period can currently not be recommended. There is no reliable data to refine the time needed for this activity. The experts agreed that 2 h for inspection should be still used in the calculations.

The RMS proposed a refinement of the TC using a TC of 1,400 cm^2^/h × person for workers not wearing gloves and a TC of 580 cm^2^/h × person for workers wearing gloves (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}). Some experts commented that the use of gloves could be considered unrealistic. The experts agreed that both calculations should be presented to be considered by risk managers. However, the agreed refinement of worker exposure indicated that the worker re‐entry exposure was well above the AOEL with and without the use of gloves.

#### 2.1.3.2. Other uses than the critical GAP {#efs25260-sec-0014}

*Approach followed during the AIR II peer review on diquat*

The RMS considered that contact with treated weeds (for the use in apples and tomatoes) is unlikely to result in significant levels of exposure and no exposure estimates were provided. For desiccant uses (oilseed rape), the RMS considered that there is no need for crop inspection (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}).

*Approach discussed during the pesticides peer review experts' teleconference 177*

The RMS clarified that the considerations followed during the peer review of diquat were based on the context of the original assessment that provided a result within the AOEL originally proposed by the RMS and the potential for exposure from the use on other crops was considered initially relatively insignificant (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}). As the peer review conclusion adopted a lower AOEL and higher dermal absorption values, it was deemed appropriate to consider potential for exposure from the use on other crops.

The RMS commented that crop inspection is not considered necessary for most of the other crops under assessment. However, for the use as a desiccant on oilseed rape, a check of the moisture content of the crop would be needed after treatment. The experts commented that oilseed rape is a difficult crop to walk in; people in general do not re‐enter the field. However, if done, the time needed for crop inspection is shorter than 2 h. The RMS proposed 10 min (considering walking at the edge of the field). This value is coming from practical experience taken from experts in the UK and other Member State specialised in the field of efficacy. However, there is some uncertainty about the proposed values of 10 min.

The RMS proposed to use a TC of 1,400 cm^2^/h × person for workers not wearing gloves and a TC of 580 cm^2^/h × person for workers wearing gloves (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}). Some experts commented that the use of gloves could be considered unrealistic. The experts agreed that both calculations should be presented to be considered by risk managers. The agreed refinement indicated that the worker re‐entry exposure was below the AOEL with and without the use of gloves.

For other uses than for those as a desiccant, i.e. weed control, the RMS still considered that contact with treated weeds is unlikely to result in significant levels of exposure. Although some experts considered that a re‐entry might occur, the majority of experts agreed that re‐entry for workers for weed control uses is unlikely.

2.2. Representative uses for Diquat 20% SL {#efs25260-sec-0015}
------------------------------------------

In the EFSA conclusion (EFSA, [2015a](#efs25260-bib-0002){ref-type="ref"}), the exposure values for the critical GAPs were presented. These estimates were covering other uses with lower application rates. For the current assessment, weed control uses in potato, onion, chicory and sugar beet have been selected as the less critical GAPs in terms of lower application rate compared to the use as a desiccant in potato and for weed control in orchards.

EFSA noted that the GAP table in the RAR included an additional use on vineyard where the method of application was 'applied directly to base of vines using specialised curtained/protected brush application equipment'. This method of application is not covered by current models for plant protection products. Therefore, it was not assessed during the AIR II peer review or during this updated assessment.

An overview table summarising the outcome of the non‐dietary exposure to diquat in Diquat 20% SL is included in Appendix [B](#efs25260-sec-1002){ref-type="sec"}. The results are discussed below.

### 2.2.1. Operator exposure to diquat in Diquat 20% SL {#efs25260-sec-0016}

#### 2.2.1.1. Critical GAPs {#efs25260-sec-0017}

The application with a conventional field crop sprayer for the use as desiccant in potato represents the critical GAP. The use to control weeds in orchards (e.g. pome fruit) represents the critical GAP with regard to hand held application. A higher tier operator field study was not available for the representative uses for Diquat 20% SL.

Operator exposure estimates indicated an exceedance of the AOEL according to UK and German Model, even if personal protective equipment is used.

#### 2.2.1.2. Other uses than the critical GAP {#efs25260-sec-0018}

Operator exposure estimates indicated an exceedance of the AOEL according to UK and German Model even if personal protective equipment is used.

### 2.2.2. Bystander and resident exposure to diquat in Diquat 20% SL {#efs25260-sec-0019}

Bystander and resident exposure to diquat in Diquat 20% SL was calculated using the approach that was agreed during the peer review. As requested by the European Commission the original German approach and the EFSA calculator including also the SVC approach are also presented under Sections [2.2.2.1](#efs25260-sec-0020){ref-type="sec"} and [2.2.2.2](#efs25260-sec-0021){ref-type="sec"}. The outcome of the different approaches was further discussed during the pesticides peer review experts' teleconference 177 as presented in Section [3.2](#efs25260-sec-0027){ref-type="sec"}.

#### 2.2.2.1. Critical GAPs {#efs25260-sec-0020}

*Approach followed during the AIR II peer review on diquat*

Following the same approach as described in Section [2.1.2.2](#efs25260-sec-0011){ref-type="sec"} using relevant input parameters for Diquat 20% SL the bystander and resident exposure estimates indicated an exceedance of the AOEL in all cases (UK approach, German approach, and re‐entry of general public).

*German approach without exposure to vapour*

The original German approach refers to the publication by Martin et al. ([2008](#efs25260-bib-0007){ref-type="ref"}). It is noted that according to that publication no exposure to airborne concentration should be taken into account for substances with a low vapour pressure such as diquat. Buffer distances of 1, 5 and 10 meters were considered. Exposure estimates indicated an exceedance of the AOEL (considering bystander and resident located at distances of 1, 5 and 10 m).

*Bystander and resident exposure according to the EFSA calculator including also the saturated vapour concentration approach*

Exposure estimates for the critical GAP were not calculated during this updated assessment since exposure estimates for other uses than the critical GAPs indicated already an exceedance of the AOEL (see Section [2.2.2.2](#efs25260-sec-0021){ref-type="sec"}).

#### 2.2.2.2. Other uses than the critical GAP {#efs25260-sec-0021}

*Approach followed during the AIR II peer review on diquat*

Following the same approach as described in Section [2.1.2.2](#efs25260-sec-0011){ref-type="sec"} and using relevant input parameters for Diquat 20% SL, exposure estimates indicated an exceedance of the AOEL in all cases (UK approach, German approach and re‐entry of general public).

*German approach without exposure to vapour*

Exposure estimates indicated no exceedance of the AOEL for bystander and resident located at 10 m. No calculations were done for shorter distances.

*Bystanders and residents exposure according to the EFSA calculator including also the saturated vapour concentration approach*

Bystanders and residents exposure according to the EFSA model (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}) have been calculated considering a 10 m buffer distance, oral absorption of 4% and a vehicle‐mounted‐drift reduction. A refinement using a SVC approach (European Commission, [2011](#efs25260-bib-0005){ref-type="ref"}) was also included in the calculations. Input parameters as described in Table [1](#efs25260-tbl-0001){ref-type="table"} (the vapour pressure of 4 × 10^−6^ Pa has been used in the calculations) were used.

According to the HEEG opinion (European Commission, [2011](#efs25260-bib-0005){ref-type="ref"}), the SVC is equal to 0.41 × Molecular Weight × Vapour Pressure (mg/m^3^). Taking into account the input parameters presented in Table [1](#efs25260-tbl-0001){ref-type="table"}, the SVC of diquat would be 0.0003 mg/m^3^.

Child and adult bystander and child resident exposure to diquat via [spray drift]{.ul} showed an exceedance of the AOEL whereas adult resident exposure showed no exceedance of the AOEL.

Bystander and resident exposure to default [vapour]{.ul} concentration of 0.001 mg/m^3^ showed an exceedance of the AOEL for both child and adult. Bystander and resident exposure from SVC showed an exceedance of the AOEL for children whereas no exceedance is shown for adults.

Bystander and resident exposure to diquat via [surface deposits]{.ul} showed no exceedance of the AOEL.

Exposure estimates via [entry into treated crops]{.ul} for bystander and resident (child and adult) showed an exceedance of the AOEL.

### 2.2.3. Worker exposure to diquat in Diquat 20% SL {#efs25260-sec-0022}

#### 2.2.3.1. Critical GAP {#efs25260-sec-0023}

*Approach followed during the AIR II peer review on diquat*

The RMS considered that only for the use as a desiccant in potato there was a need for crop inspection. The quantitative assessment for re‐entry into treated field for this use on potato indicated an exceedance of the AOEL.

*Approach discussed during the pesticides peer review experts' teleconference 177*

The RMS clarified that the considerations followed during the peer review of diquat were based on the context of the original assessment that provided a result within the AOEL originally proposed by the RMS and the potential for exposure from the use on other crops was considered initially to be relatively insignificant (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}). As the peer review conclusion adopted a lower AOEL and higher dermal absorption values, it was appropriate to consider potential for exposure from the use on other crops.

During the pesticides peer review experts' teleconference 177, the RMS confirmed that for desiccant uses on potato there is a need for crop inspection. Inspection is needed to check if the treatment was efficient. A default TC of 2,500 cm^2^/h × person (van Hemmen et al., [2002](#efs25260-bib-0006){ref-type="ref"}) and 2 h for inspection were initially used in the calculations. The RMS commented that 2 h could be considered too long for this activity. However, a reliable shorter period can currently not be recommended. There is no reliable data to refine the time needed for this activity. The experts agreed that 2 h for inspection should be still used in the calculations.

The RMS proposed a refinement of the TC using a TC of 1,400 cm^2^/h × person for workers not wearing gloves and a TC of 580 cm^2^/h × person for workers wearing gloves (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}). Some experts commented that the use of gloves could be considered unrealistic. The experts agreed that both calculations should be presented to be considered by risk managers. However, the agreed refinement of worker exposure indicated that the worker re‐entry exposure was well above the AOEL with and without the use of gloves.

#### 2.2.3.2. Other uses than the critical GAP {#efs25260-sec-0024}

*Approach followed during the AIR II peer review on diquat*

The RMS considered that contact with treated weeds (weed control, potato, onion, carrot, chicory, sugar beet, pome fruit, stone fruit, citrus fruit, olive, tree nut and vineyard) is unlikely to result in significant levels of exposure and no exposure was proposed. For desiccant uses (oilseed rape, sunflower, peas, beans), the RMS considered that there is no need for crop inspection (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}).

*Approach discussed during the pesticides peer review experts' teleconference 177*

The RMS clarified that the considerations followed during the AIR II peer review of diquat were based on the context of the original assessment that provided a result within the AOEL originally proposed by the RMS and the potential for exposure from the use on other crops was considered initially to be relatively insignificant (United Kingdom, [2015](#efs25260-bib-0008){ref-type="ref"}). As the peer review conclusion adopted a lower AOEL and higher dermal absorption values, it was appropriate to consider potential for exposure from the use on other crops.

The RMS commented that crop inspection is not considered necessary for most of the other crops under assessment. However, for the use as a desiccant on oilseed rape, a check of the moisture content of the crop would be needed after treatment. The experts commented that oilseed rape is a difficult crop to walk in; people in general do not re‐enter the field. However, if done, the time needed for crop inspection is shorter than 2 h. The RMS proposed 10 min (considering walking at the edge of the field). This value is coming from practical experience taken from experts in the UK and other MS specialised in the field of efficacy. However, there is some uncertainty about the proposed values of 10 min.

The RMS proposed to use a TC of 1,400 cm^2^/h × person for workers not wearing gloves and a TC of 580 cm^2^/h × person for workers wearing gloves (EFSA, [2014](#efs25260-bib-0001){ref-type="ref"}). Some experts commented that the use of gloves could be considered unrealistic. The experts agreed that both calculations should be presented to be considered by risk managers. The agreed refinement indicated that the worker re‐entry exposure was below the AOEL with and without the use of gloves.

For other desiccant uses than for potato and oilseed rape, i.e. sunflower, peas and beans, the RMS considered that there is no need for crop inspection. The majority of experts agreed that no re‐entry is needed.

For other uses than desiccant, i.e. weed control, the RMS considered that contact with treated weeds is unlikely to result in significant levels of exposure. Although some experts considered that re‐entry might occur, the majority of experts considered that re‐entry worker for weed control uses is unlikely.

3. Overall scientific conclusion {#efs25260-sec-0025}
================================

3.1. Representative uses for Reglone (A1412A) {#efs25260-sec-0026}
---------------------------------------------

**Operator**: Exposure of operators to diquat in Reglone (A1412A) was below the AOEL considering the critical GAP, i.e. desiccant use in potato under the following conditions: maximum application rate of 0.8 kg a.s./ha and coveralls and gloves during mixing/loading, maintenance work and application and tractor fitted with closed cabin (higher tier exposure field study for potato). The higher tier exposure field study for potato covered other uses than the critical GAP.**Bystander and resident**: Considering all representative uses, exposure of bystanders and residents to diquat in Reglone (A1412A) was below the AOEL only if the original German approach (see Section [2.1.2](#efs25260-sec-0009){ref-type="sec"}) is considered and bystanders and residents are located at a distance of 5 or 10 m from the treated field. During the pesticides peer review experts' teleconference 177, Germany commented that they are not supporting any longer the original German approach since exposure of bystanders and residents is underestimated. All the experts considered that the original German approach is scientifically not supported. On the basis of the UK approach, exposure of bystanders and residents to diquat in Reglone (A1412A) is above the AOEL (maximum exposure is driven by exposure to diquat via drift and general public re‐entering the field). This is confirmed when the EFSA ([2014](#efs25260-bib-0001){ref-type="ref"}) guidance is applied, even if the following conditions are considered: application rate of 0.6 kg a.s./ha, 10 m distance, vehicle‐mounted‐drift reduction, oral absorption of 4% and refinement for SVC. Under these conditions, bystander and resident (child) exposure to diquat via [spray drift]{.ul} showed an exceedance of the AOEL, whereas bystander and resident (adult) exposure to diquat showed no exceedance of the AOEL. Bystander and resident (for both child and adult) exposure to default [vapour]{.ul} concentration of 0.001 mg/m^3^ showed an exceedance of the AOEL. Bystander and resident exposure from SVC showed an exceedance of the AOEL for the child, whereas no exceedance is shown for adults. Bystander and resident (adult and child) exposure to diquat via [surface deposits]{.ul} showed no exceedance of the AOEL. Bystander and resident (for both child and adult) exposure to diquat via [entry into treated crops]{.ul} showed exceedance of the AOEL. The experts discussed whether engineering or restricted access to crops should be taken into account for the risk assessment: engineering or restricted access to crops are very difficult to implement. Currently, no data are available to support these measures. The experts commented that engineering or restricted access might not even be sufficient to reduce exposure levels below the AOEL.**Worker:** Exposure of re‐entry workers during crop inspection was considered only necessary for desiccant use on potato and oilseed rape. Exposure estimates were above the AOEL for the use as desiccant in potato (with and without the use of gloves) and below the AOEL for oilseed rape (with and without the use of gloves). For the other uses assessed, re‐entry was considered not necessary.

3.2. Representative uses for Diquat 20% SL {#efs25260-sec-0027}
------------------------------------------

**Operator:** Exposure of operators to diquat in Diquat 20% SL was above the AOEL for all the representative uses even with the use of personal protective equipment according to the German model and UK model.**Bystander and resident:** For other uses than for the critical GAP, exposure of bystanders and residents to diquat in Diquat 20% SL was below the AOEL only if the original German approach is considered (see Section [2.2.2](#efs25260-sec-0019){ref-type="sec"}) and bystanders and residents are located at a distance of 10 m from the treated field. For the critical GAP, exposure of bystanders and residents was above the AOEL following the original German approach. During the pesticides peer review experts' teleconference 177, Germany commented that they are not supporting any longer the original German approach since exposure of bystanders and residents is underestimated. All the experts considered that the original German approach is scientifically not supported. On the basis of the UK approach, exposure of bystanders and residents to diquat in Diquat 20% SL is above the AOEL (maximum exposure is driven by exposure to diquat via drift and general public re‐entering the field). This is confirmed when the EFSA ([2014](#efs25260-bib-0001){ref-type="ref"}) guidance is applied, even if the following conditions are considered: application rate of 0.4 kg a.s./ha, 10 m distance, vehicle‐mounted‐drift reduction, oral absorption of 4% and refinement for SVC. Under these conditions, bystander (child and adult) and resident (child) exposure to diquat via [spray drift]{.ul} showed an exceedance of the AOEL, whereas resident (adult) exposure to diquat showed no exceedance of the AOEL. Bystander and resident (for both child and adult) exposure to default [vapour]{.ul} concentration of 0.001 mg/m^3^ showed an exceedance of the AOEL. Bystander and resident exposure from SVC showed an exceedance of the AOEL for child whereas no exceedance is shown for adults. Bystander and resident (both adult and child) exposure to diquat via [surface deposits]{.ul} showed no exceedance of the AOEL. Bystander and resident (both child and adult) exposure to diquat via [entry into treated crops]{.ul} showed an exceedance of the AOEL. The experts discussed whether engineering or restricted access to crops should be taken into account for the risk assessment: engineering or restricted access to crops are very difficult to implement. Currently, no data are available to support these measures. The experts commented that engineering or restricted access might not even be sufficient to reduce the exposure levels below the AOEL.**Worker:** Exposure of re‐entry workers for crop inspection was considered only necessary for the use as a desiccant on potato and oilseed rape. Exposure estimates were above the AOEL for use in potato and oilseed rape (with and without the use of gloves). For other uses, re‐entry was considered not necessary.

3.3. Overview of the concerns identified for each representative use considered {#efs25260-sec-0028}
-------------------------------------------------------------------------------

Representative use**Potato (desiccant, 1 kg a.s./ha)Oilseed rape (desiccant, 0.6 kg a.s./ha)Apple (herbicide, 1 kg a.s./ha dormancy stage)Tomato (herbicide, 0.8 kg a.s./ha pre‐emergence)Tomato (herbicide, 0.8 kg a.s./ha, inter‐row shielded)Potato (desiccant, 0.8 kg a.s./ha)Potato (desiccant, 2 × 0.4 kg a.s./ha)Potatoes (herbicide, pre‐emergence 0.4 kg a.s./ha)Sunflower, (desiccant, 0.6 g a.s./ha)Pulses (desiccant, 0.6 kg a.s./haCarrot (herbicide, pre‐emergence 0.4 kg a.s./ha)Chicory (herbicide, pre‐emergence 0.4 kg a.s./ha)Sugar beet (herbicide, pre‐emergence 0.4 kg a.s./ha)Onion (herbicide, 0.4 kg a.s./ha)Olive (herbicide, 1 kg a.s./ha, all season)Citrus, Pome fruit, Stone fruit,Tree nuts (herbicide, 1 kg a.s./ha, all season)Grapevines (herbicide, 1 kg a.s./ha, all season)Operator risk**Risk identifiedX^4^X^4^X^4^X^4^X^4^X^4^X^4^X^4^X^4^X^4^X^4^X^4^Assessment not finalised**Worker risk**Risk identifiedX^3^X^6^X^6^Assessment not finalised**Bystander/Resident risk**Risk identifiedX^2^X^2^X^2^X^2^X^2^X^5^X^5^X^5^X^5^X^5^X^5^X^5^X^5^X^5^X^5^X^5^X^5^Assessment not finalised

Abbreviations {#efs25260-sec-0029}
=============

a.s.active substanceAOELacceptable operator exposure levelARapplied radioactivitybwbody weightDT~50~period required for 50% dissipation (define method of estimation)DT~90~period required for 90% dissipation (define method of estimation)EECEuropean Economic CommunityGAPGood Agricultural PracticeGMgeometric meanISOInternational Organization for StandardizationOECDOrganisation for Economic Co‐operation and DevelopmentPIEpotential inhalation exposurePPEpersonal protective equipmentRARRenewal Assessment ReportREACHRegistration, Evaluation, Authorisation of Chemicals RegulationRPErespiratory protective equipmentSCsuspension concentrateSVCsaturated vapour concentrationTCtransfer coefficient

Appendix A -- Overview of non‐dietary exposure estimates to diquat in Reglone (A1412A) {#efs25260-sec-1001}
======================================================================================

 {#efs25260-sec-0030}

 

Appendix B -- Overview of non‐dietary exposure estimates to diquat in Diquat 20% SL {#efs25260-sec-1002}
===================================================================================

 {#efs25260-sec-0031}

 

Appendix C -- Application parameters for the representative PPPs {#efs25260-sec-1003}
================================================================

 {#efs25260-sec-0032}

 

Appendix D -- Detailed calculations. Reglone (A1412A) {#efs25260-sec-1004}
=====================================================

 {#efs25260-sec-0033}

 

Appendix E -- Detailed calculations. Diquat 20%SL {#efs25260-sec-1005}
=================================================

 {#efs25260-sec-0034}

Appendix A, B, C, D and E can be found in the online version of this output ('Supporting information' section): <https://doi.org/10.2903/j.efsa.2018.5260>

Supporting information
======================

###### 

Overview of non‐dietary exposure estimates to diquat in Reglone (A1412A)

###### 

Click here for additional data file.

###### 

Overview of non‐dietary exposure estimates to diquat in Diquat 20% SL

###### 

Click here for additional data file.

###### 

Application parameters for the representative PPPs

###### 

Click here for additional data file.

###### 

Detailed calculations. Reglone (A1412A)

###### 

Click here for additional data file.

###### 

Detailed calculations. Diquat 20%SL

###### 

Click here for additional data file.

Commission Regulation (EU) No 1141/2010 of 7 December 2010 laying down the procedure for the renewal of the inclusion of a second group of active substances in Annex I to Council Directive 91/414/EEC and establishing the list of those substances. OJ L 322, 8.12.2011, p. 10--19.

The superscript numbers in this table relate to the numbered points indicated in Sections [3.1](#efs25260-sec-0026){ref-type="sec"} and [3.2](#efs25260-sec-0027){ref-type="sec"}.
