Common pesticides 'can kill frogs within an hour'

New research suggests the chemicals are playing a significant and previously unknown role in the global decline of amphibians

Widely used pesticides can kill frogs within an hour, new research has revealed, suggesting the chemicals are playing a significant and previously unknown role in the catastrophic global decline of amphibians.

The scientists behind the study said it was both "astonishing" and "alarming" that common pesticides could be so toxic at the doses approved by regulatory authorities, adding to growing criticism of how pesticides are tested.

... pesticides are not required to be tested on amphibians, said Brühl: "We could only find one study for one pesticide that was using an exposure likely to occur on farmland."

His team chose widely used fungicides, herbicides and insecticides. The most striking results were for a fungicide called pyraclostrobin, sold as the product Headline by the manufacturer BASF and used on 90 different crops across the world. It killed all the common European frogs used as test animals within an hour when applied at the rate recommended on the label. Other fungicides, herbicides and insecticides also showed acute toxicity, even when applied at just 10% of the label rate, with the insecticide dimethoate, for example, killing 40% of animals within a week.

Brühl said the method, a single spray directly on to the frogs, sometimes at just 10% of the label rate, was a "realistic worst-case" scenario. He added that in the field, multiple sprays of a variety of pesticides was likely and that chemicals might run off into ponds where frogs lived.