An apple a day may keep the doctor away—but it could also mean you’re consuming potentially harmful levels of toxic pesticides. 

Apples, along with grapes, strawberries, nectarines and spinach, top the list for the highest traces and widest variety of pesticides that have been linked to cancer and reproductive problems, according to research from The Environmental Working Group (EWG).

The body has warned that a combination of chemicals may result in more harm to human health due to toxins that are released when they interact. 

Strawberries topped the list with an average of 7.8 different pesticides per sample, including carbendazim, which has been linked in studies to infertility and cancer.

Investigations have previously found strawberries may be rife with carbendazim, as well as a compound called bifenthrin, which is thought to have potential neurological effects.

For the latest analysis, experts sampled 46 fruits and vegetables, 12 of which were the most contaminated with pesticides—including kale, pears, peaches, peppers, cherries, blueberries and green beans.   

The team analysed tens of thousands of samples collected by the Agricultural Department and the Food and Drug Administration in the US. 

A total of 209 pesticides were found and across all 12 items, with 95 percent of samples carrying traces of at least one chemical. 

Several everyday favorites are some of the worst offenders for contamination, including apples, grapes, strawberries, nectarines and spinach

The Dirty Dozen, a test conducted by the Environmental Working Group, includes the top twelve fruits and vegetables with the highest pesticide residues

The most frequently detected chemicals were anti-fungal pesticides such as fludioxonil, pyraclostrobin, boscalid and pyrimethanil. 

Some studies suggest fludioxonil can cause DNA damage which could lead to increased cancer risk, according to the National Institues of Health.

The body also warns that boscalid has been shown, in rare cases, to cause damage to cells that some scientists believe can lead to the development of cancerous tumours.

Pyrimethanil, while relatively low toxicity for humans, has been shown to disrupt hormone regulation in animals, which could impact reproduction.

‘Emerging evidence suggests many widely used fungicides may disrupt human hormone systems,’ said EWG senior toxicologist Dr Alexis Temkin. 

Spinach was another poor performer: tests detected an average of seven pesticides on conventional spinach samples, with up to 19 different pesticides on one of the samples tested.

Three-fourths of the samples were contaminated with a neurotoxic insecticide, permethrin, which is banned from use on food crops in Europe.

At high doses, permethrin is thought to affect the nervous system, risking tremors and seizures. 

Apples were found to contain very high levels of diphenylamine, which can damage various organs and systems in the body through consistent and long term exposure.

It can be toxic to the blood, kidneys, liver, and bladder.

According to the European Commission, food businesses must ensure that what they produce or import is compliant with maximum safety residue levels.

However the law doesn’t stipulate a specific threshold.

Speaking of the risk of multiple pesticides, UK lobby group Pesticide Action Network UK said: ‘The government sets safety limits for just one pesticide at a time, ignoring the growing body of evidence that chemicals can become more harmful when combined.

‘Several pieces of research conducted on human cells and tissues have highlighted that pesticide mixtures can lead to the creation of cancer cells and disruption of the endocrine system, which produces hormones that regulate metabolism, growth and development, tissue function, sexual function and reproduction.

‘Pesticide mixtures have been associated with obesity and impaired liver function, even when the doses of individual chemicals are below the safety levels set by regulators,’ the group added.

The EWG advised switching to organic or at least washing the fruit and veg and peeling where possible.

Pesticides are applied on fruits and vegetables to prevent or kill fungal diseases like powdery mildew. They’re often used after harvest to keep produce mould-free on its way to market.