How to test nontarget effects of veterinary pharmaceutical residues in livestock dung in the field.

To register veterinary medicinal products (VMPs) as parasiticides on pastured animals, legislation in the European Union requires an environmental risk assessment to test the potential nontarget effects of fecal residues on dung-dwelling organisms. Products with adverse effects in single-species laboratory tests require further, higher-tier testing to assess the extent of these effects on entire communities of dung-dwelling organisms under more realistic field or semifield conditions. Currently, there are no documents specifically written to assist researchers in conducting higher-tier tests or to assist regulators in interpreting the results of such tests in an appropriate context. Here we provide such a document, written by members of the SETAC Advisory Group DOTTS (Dung Organism Toxicity Testing Standardization) with research experience on dung fauna in central and southern Europe, Canada, Australia, and South Africa. This document briefly reviews the organisms that make up the dung community and their role in dung degradation, identifies key considerations in the design and interpretation of experimental studies, and makes recommendations on how to proceed.

Insecticidal activity of synthetic pyrethroids, organophosphates, insect growth regulators, and other livestock parasiticides: an Australian perspective.

The present review is restricted to the collation and evaluation of information describing the excretion profile and ecotoxicity of veterinary medicines developed specifically for the control of either internal or external parasites of livestock. It identifies numerous gaps in our knowledge and highlights our poor understanding of the environmental fate of many of these chemicals, especially those developed for the control of ticks, lice, and/or biting flies. Residues of most anthelmintics are largely harmless to dung-feeding arthropods, but those of many ectoparasiticides, especially the synthetic pyrethroids, are highly toxic to fly larvae and adult dung beetles. Organophosphates, because they are metabolized extensively and eliminated mostly in urine, are considered to be unlikely to have a major impact on the development or survival of dung-dwelling organisms. The present review stresses the need for better information regarding spatial and temporal usage patterns of veterinary parasiticides, and it examines the role of ecotoxicological models for evaluating their impact on populations of dung-dependent arthropods.

Fecal residues of veterinary parasiticides: nontarget effects in the pasture environment.

Residues of veterinary parasiticides in dung of treated livestock have nontarget effects on dung-breeding insects and dung degradation. Here, we review the nature and extent of these effects, examine the potential risks associated with different classes of chemicals, and describe how greater awareness of these nontarget effects has resulted in regulatory changes in the registration of veterinary products.