Insecticide Contamination of Global Surface Waters is Widespread

Insecticides are used across the globe. Now, though, scientists have discovered that there is global contamination of surface waters.

The environmental risk assessment for pesticides is mandatorily conducted by regulatory agencies prior to their authorization. In theory, these risk assessments should ensure that pesticide applications do not lead to unacceptable adverse effects on aquatic and terrestrial ecosystems or on human health.

In this latest study, the researchers evaluated the comprehensive global insecticide contamination data for agricultural surface waters using the legally-accepted regulatory threshold levels (RTLs) as defined during the official pesticide authorization procedures. They found more than 40 percent of the water-phase samples with a detection of an insecticide concentration exceeded respective RTLs. In addition, more than 80 percent of insecticide concentrations in sediments exceeded RTLs.

The researchers considered 28 insecticide compounds in total, of which the majority is currently authorized in the EU or the U.S., respectively. It's also comprised in total 11,300 insecticide concentrations detected in more than 2,500 surface water sites located in 73 countries.

The findings reveal that insecticide contamination is far more widespread and prevalent than expected. In addition, there may be resulting adverse effects from mixtures of insecticides rather than single compounds. More specifically, it shows that new regulations need to be put into effect in order to better control these substances in the future, especially as they mingle in water.

The findings are published in the journal Proceedings of the National Academy of Sciences.

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