What are heavy metals?

Heavy metals (HM) are naturally occurring elements found in the environment. These metals have relatively high densities - at least five times the density of water. Normal levels of HM are generally not an issue to humans and animals.

However, human activity can increase the amounts of heavy metals present in the environment. Pollutants from industries, pesticides from agriculture as well as car exhaust fumes, all contribute to HM contamination.

The contamination builds up in soil and water and gets into the human food chain. Whilst certain heavy metals are important to human health - such as zinc and copper - in higher concentrations, heavy metals are toxic and dangerous to human health.

Why is heavy metal testing relevant to CBD?

Cannabis and industrial hemp have great eco-profiles. They are quick-growing and low maintenance crops that absorb CO2 from the atmosphere.

But cannabis and hemp are also phytoremediators. This means they are very effective for removing chemical and pollutants from the soil. All plants absorb heavy metals and other chemicals from the soil, but cannabis and hemp are particularly good at it.

When industrial hemp is used for fibre, this bioaccumulation by the plant is a good thing. Contaminated soil can be cleaned up by growing hemp, for example.

However, when hemp is grown for the purposes of CBD extraction, it becomes a foodstuff. This means that the extracted CBD may introduce these accumulated heavy metals into our food chain.

So, heavy metals testing is important for any food plant. Industrial hemp’s ability to absorb HM means it is more necessary to do heavy metal testing for CBD products.

Soil pollution in the EU

An investigation by the European Insititute for Environment and Sustainability in 2014 assessed the concentrations of heavy metals in the soil of the EU.

The majority of agricultural land was considered safe for food production. Around 6% of samples were found to have higher concentrations of heavy metals. The investigation recommends that the affected 137,000 km2 of land undergo further assessment and possible remedial action.

However, the overall number of samples with one or more heavy metal concentrations above the assessment’s threshold was concerning. This has raised the need for remediation and management of soil resources across Europe.

Heavy metal contamination is a problem for the soil in the EU. As a result, heavy metal testing remains essential.

What are the health risks of heavy metals?

Acute heavy metal poisoning occurs from a single high dose and causes headaches, vomiting and loss of consciousness.

Chronic heaving metal poisoning comes from low doses but over a long time. The metal builds up in the body and gradually produces symptoms like headaches, tiredness and aching joints.

Each heavy metal has differing toxicity and affects human health in different ways. Here are three heavy metals and the risk they pose:


Over half a million deaths each year are estimated to be caused by lead exposure. The brain is particularly susceptible to the effects of lead poisoning, which can cause seizures and confusion. Lead contamination comes from smelting, manufacturing and from car and aviation fuels.

Children are at increased risk of lead poisoning as their growing bodies absorb the lead into their bones and organs. Lead poisoning can lead to premature and low-birth-weight in babies, miscarriage and reduced fertility. There is no known level of safe exposure to lead.


Apex marine predators, like swordfish and tuna, may contain raised amounts of mercury. At high levels, mercury exposure can harm the brain, heart, lungs and immune system.

Human activity accounts for half of the mercury entering the environment each year. One-third of the human contribution comes from the gold industry and a quarter from power generation.


Arsenic is a poisonous substance often used in classic murder-mystery novels as a murder weapon. However, long-term exposure can cause cancer, skin lesions and cardiovascular disease. Arsenic may also affect cognitive development in children.

Globally, arsenic is the most significant chemical contaminant found in drinking water. The uses of arsenic include the processing of glass, textiles, paper and as a wood preservative.

Why choose PhytoVista Laboratories as your heavy metals testing lab?

PhytoVista Laboratories is an established science lab based in Frome, Somerset. Our analytical chemistry experience spans decades and includes industries such as agrochemicals, pharmaceutical R&D, and the refinement and purification of chemical compounds.

Get a quote for your product’s CBD heavy metal testing with PhytoVista Laboratories today.


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