Effects of chlorpyrifos, carbendazim and linuron on the ecology of a small indoor aquatic microcosm

• Published in: Archives of environmental contamination and toxicology 2007-07, Vol.53 (1), p.22-35
• Main Authors: Daam, M.A, Brink, P.J. van den
• Format: Article
• Language: English
• Subjects: active ingredient chlorpyrifos; Animal, plant and microbial ecology; Animals; Applied ecology; Aquatic plants; Benzimidazoles - toxicity; Biological and medical sciences; Carbamates - toxicity; Chlorophyll - analysis; Chlorpyrifos; Chlorpyrifos - toxicity; Closed systems; Ecology - methods; Ecosystem; ecosystem metabolism; Ecosystem studies; Ecotoxicology, biological effects of pollution; Fresh Water; fresh-water microcosms; Freshwater; Fundamental and applied biological sciences. Psychology; fungicide carbendazim; Fungicides; General aspects; herbicide linuron; Herbicides; Hydrogen-Ion Concentration; insecticide dursban(r) 4e; Invertebrates - classification; Invertebrates - drug effects; Invertebrates - physiology; Laboratory tests; Linuron - toxicity; Macroinvertebrates; macrophyte-dominated mesocosms; Microcosms; model-ecosystems; Nitrates - analysis; No-Observed-Adverse-Effect Level; outdoor experimental ditches; Oxygen - analysis; Pesticides; Pesticides - toxicity; Phosphates - analysis; Population Density; primary producers; Quaternary Ammonium Compounds - analysis; Risk assessment; Risk Assessment - methods; Studies; Taxa; Water Pollutants, Chemical - toxicity
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-006-0001-y

To validate the use of small indoor microcosms for the risk assessment of pesticides, the fate and effects of chlorpyrifos, carbendazim, and linuron were studied in 8.5-liter indoor freshwater microcosms. Functional and structural responses to selected concentrations were evaluated and compared with responses observed in larger-scale model ecosystem studies. Overall, the microcosms adequately displayed the chain of effects resulting from the application, although they did not always predict the exact fate and responses that were observed in larger semifield studies. Because closed systems were used that did not contain sediment and macrophytes, pesticides were relatively persistent in the present study. Consequently, calculated toxicity values were generally more comparable with those reported in studies with long- than with short-term exposure. Carbendazim had a higher overall no-observed-effect concentration (NOEC) compared with experiments performed in larger systems because macroinvertebrate taxa, the most sensitive species group to this fungicide, were not abundant or diverse. Future refinements to the test system could include the addition of a sediment compartment and sensitive macroinvertebrate taxa. However, the simple design offers the potential to perform experiments under more controlled conditions than larger and, consequently, more complex model ecosystems, while maintaining relatively high ecologic realism compared with standard laboratory tests. Further implications for risk-assessment studies are discussed in an ecotoxicologic and methodologic context.