New test strategy for dung beetles during the authorization process of parasiticides.

According to European legislation, an environmental risk assessment (ERA) of veterinary medicinal products (VMPs) for dung fauna is required in the authorization process, if the substance acts as a parasiticide for the treatment of pasture animals. In the past, however, the demonstration of the environmental safety of those VMPs for dung fauna was strongly hampered by the fact that no standardized tests were available. Therefore, starting with recommendations from the Society of Environmental Toxicology and Chemistry (SETAC) advisory group, dung organism toxicity test standardization (DOTTS) test systems for phase II Tier A standardized tests on the mortality of dung fly and dung beetle larvae were developed and published by the Organisation for Economic Co-operation and Development (OECD) in 2008 and 2010. If a risk is identified for dung organisms in phase II Tier A of the ERA process, further tests are required for Tier B. So far, however, no advice is given for such studies in the existing guidelines. Therefore, 4 workshops took place between 2007 and 2009 with international dung fauna experts (Aveiro-Group) to find an appropriate test strategy for dung fauna organisms beyond Tier A mortality testing. For the first time, 2 different Tier B extended laboratory test approaches for dung beetles and test strategies for scenarios beyond Tier B are described in more detail. In case the risk assessment is still not clear, further options for Tier C (i.e., field studies) or Tier D (modeling) are briefly presented. Finally, the role of uncertainty and variability of test results is discussed, including recommendations for assessment factors for the different tiers to be used when assessing the risk of VMPs on dung organisms. The approach, especially the test strategy, will help industry, consultants, and assessors appropriately assess the environmental risk assessments during the authorization procedure of parasiticides.