Since January 1, 2018, there has been a purification obligation in the Netherlands for wastewater discharges from greenhouse horticulture. The purification efficiency is 95%. According to research from the environmental organization Pesticides Action Network (PAN), the concentrations of individual pesticides did not exceed national or European water standards, but a sampling of rain and surface waters around greenhouses in Belgium, Netherlands, Spain, and Germany still show 'an alarmingly high number' of products. According to their research, this includes substances commonly used in greenhouses and even those outlawed years ago. "It shows that greenhouses are not closed places and do not merit a less stringent regime when (re)approving pesticides."

The report "It rains pesticides from greenhouses!" is published today by the Pesticides Action Network (PAN) Europe.

According to their research, dozens of pesticides were detected in samples of rain and surface waters taken in areas where greenhouses were the only or predominant agricultural activity. "As many as 35 different pesticides were detected in one rainwater sample from the Netherlands and 23 in a surface water sample from Spain. The number of pesticides detected was high in all four EU member states included in the snapshot sampling procedure and included many prohibited substances."

While the concentrations of individual pesticides did not exceed national or European water standards, the organization still says the combined presence is cause for alarm. "Our study recorded combined concentrations of up to 90 μg/l in Belgian surface water and 21 μg/l in rainwater samples. This is 180 and 42 times more, respectively, than the recently proposed 0.5 μg/l total pesticide threshold in surface water. This is concerning because their toxicity in terms of mixture effects is not properly assessed under the EU pesticide safety/risk assessment procedure, despite legal requirements to account for cumulative - or additive, and synergistic - or magnifying effects."

PAN Europe strives for more strict approval or even banning of pesticides for use in greenhouses, as they say, the nature of these products, as well as their concentrations, pose risks to ecosystems, biodiversity, and human health. Hans Muilerman, Chemicals Coordinator at PAN Europe, said: "The EU should urgently stop approving otherwise banned pesticides for use in greenhouses. Greenhouses are not closed and must be subject to an adequate pesticide risk assessment."

"We find, time and again, that greenhouses are not closed systems. A ban on any pesticide must now mean it's banned from greenhouses, too," adds Manon Rouby, PAN Europe's Policy Officer and Legal Adviser.

Download the full report here.