People living near farms across Europe — including in the Netherlands — are regularly exposed to complex mixtures of pesticides, according to a new scientific study. And while exposure to individual substances remain within safe limits, researchers warn that the combined effect of these chemical cocktails is not being properly assessed.

The Sprint study, presented this week in Brussels, analysed blood, urine, stool samples and wristbands from over 600 volunteers in ten European countries.

The study is special given its focus on real-life exposure – not just what farmers are permitted to spray, but what people actually come into contact with at home.  In total, researchers identified some 100 different pesticides in and around homes near agricultural areas.

Paul Scheepers, a toxicologist at Radboud University and co-author of the study, said the findings underline the need for systematic monitoring across Europe. “We’re not signalling risks,” he told the Volkskrant, “but these substances are present, and we should track that exposure structurally.”

While most detected substances were within EU safety margins, researchers say they are concerned about cumulative effects. A follow-up study will test the combined effect of the three most common authorised pesticides in laboratory conditions, with a focus on fertility risks.

Jacob de Boer, former professor of environmental chemistry at Amsterdam’s VU University, is one of 250 scientists to support a call to the EU calling for better monitoring of the impact of pesticide cocktails.

“The number of approved chemicals is growing, and while not all are dangerous, we simply don’t know enough about what happens when they combine,” he told the paper.

Earlier this year, the Dutch government agency that monitors pesticide safety said is is going to change the way it assesses their carcinogenic effects after years of “getting it wrong”.

Checking the effect of pesticides on animals currently involves two-tailed testing which assesses both the risk of cancer from a pesticide and its potential protective effect. But this form of testing has been shown to be unreliable and may have left animals with tumors that have been overlooked, scientists have said.