Mesocosm studies pyrethroids

Considering evidence from both field and mesocosm studies, it may be concluded that certain groups of aquatic macroinvertebrates are sensitive to pyrethroids and that there can be changes, in the short term, at the population level and above with exposure to environmentally realistic concentrations of them. It should be possible to pick up effects of this kind in natural waters using ecological profiling, for example, the River Invertebrate Prediction and Classification System (RIVPACS). There is... 

Mesocosm no-effect data on a rapidly dissipating compound such as a pyrethroid insecticide may not be suitable for a chronic EQS applied to a river. Furthermore, most existing micro- and mesocosm studies are inappropriate for EQS derivation if fish are the most sensitive species because fish have generally been excluded from such tests. There is consequently a need for evidence-based decision making for interpretation of nonstandard mesocosm studies. Microcosm and mesocosm tests can, however, be used directly for EQS derivation if algae, macrophytes, and invertebrates are appropriately represented in the test systems and if they concern substances subject to transient exposure. They are then directly applicable for the derivation of M AC-EQSs. For this purpose, the NOEAEC can be used as it represents the highest initial concentration that causes no ecologically relevant effects. 

Giddings, J.M., Solomon, K.R., and Maund, S.J. (2001). Probabilistic risk assessment of cotton pyrethroids.il Aquatic mesocosm and held studies. Environmental Toxicology and Chemistry 20, 660-668. 

Giddings JM, Solomon KR, Maund SJ (2001) Probabilistic risk assessment of cotton pyrethroids in aquatic ecosystems 2. Aquatic mesocosm and field studies observed effects and their ecological significance. Environ Toxicol Chem 20 660-668... 

Recently, metapopulation models have been successfully applied to assess the risks of contaminants to aquatic populations. A metapopulation model to extrapolate responses of the aquatic isopod Asellus aquaticus as observed in insecticide-stressed mesocosms to assess its recovery potential in drainage ditches, streams, and ponds is provided by van den Brink et al. (2007). They estimated realistic pyrethroid concentrations in these different types of aquatic ecosystems by means of exposure models used in the European legislation procedure for pesticides. It appeared that the rate of recovery of Asellus in pyrethroid-stressed drainage ditches was faster in the field than in the isolated mesocosms. However, the rate of recovery in drainage ditches was calculated to be lower than that in streams and ponds (van den Brink et al. 2007). In another study, the effects of flounder foraging behavior and habitat preferences on exposure to polychlorinated biphenyls in sediments were assessed by Linkov et al. (2002) using a tractable individual-based metapopulation model. In this study, the use of a spatially and temporally explicit model reduced the estimate of risk by an order of magnitude as compared with a nonspatial model (Linkov et al. 2002). 

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