Challenging the requirement for chronic fish toxicity studies on formulated plant protection products

Ecotoxicity testing of pesticide active ingredients and formulated plant protection products (PPPs) prior to their commercial use is required by authorities around the world. Such studies are important for the conduct of risk assessments to protect wildlife and the environment, but they should only be conducted when their use is scientifically justified. One test of questionable scientific merit is the chronic fish toxicity test when conducted with formulated PPPs, which is a potential requirement under European legislation: chronic exposure to the formulated product per se rarely occurs in the environment and therefore it is generally not possible to use the data from chronic formulation studies in a meaningful risk assessment. A recent survey of European crop protection companies to explore the scientific merits and regulatory drivers for chronic fish toxicity studies has shown that current practice in deciding on the need for chronic fish toxicity testing of formulated PPPs varies substantially between companies. The most commonly cited reason for conducting such studies was solely to meet regulatory requirements. We conclude that chronic formulation testing is rarely if ever scientifically justified, and recommend that the forthcoming revision of the EU Aquatic Toxicology Guidance Document takes account of this by including a requirement that justification must be provided for conducting the test, rather than the current situation where the onus is on the registrant to provide a justification for not conducting the test.