Ecological effects of Spring and late Summer applications of Lambda-Cyhalothrin on freshwater microcosms

• Published in: Archives of environmental contamination and toxicology 2006-02, Vol.50 (2), p.220-239
• Main Authors: Wijngaarden, R.P.A. van, Brock, T.C.M, Brink, P.J. van den, Gylstra, R, Maund, S.J
• Format: Article
• Language: English
• Subjects: active ingredient chlorpyrifos; Animal, plant and microbial ecology; Animals; Applied ecology; Aquatic Ecology; Aquatic ecosystems; Aquatic plants; aquatic risk-assessment; Aquatische ecologie; Biological and medical sciences; Chaoborus obscuripes; community responses; Community structure; Crustaceans; ditches; Drainage ditches; Ecological effects; Ecosystem; Ecotoxicology, biological effects of pollution; Environmental Toxicology, Ecotoxicology; fate; Fresh Water; Freshwater; freshwater ecology; Freshwater ecosystems; Fundamental and applied biological sciences. Psychology; Gammarus pulex; General aspects; insecticide dursban(r) 4e; Insecticides; Insecticides - toxicity; Invertebrates - classification; Invertebrates - drug effects; lambda-cyhalothrin; lente; Macroinvertebrates; mesocosms; Microcosms; Milieutoxicologie, ecotoxicologie; Nitriles - toxicity; No-Observed-Adverse-Effect Level; oppervlaktewater; organisms; Phytoplankton; Plant Development; Plants - drug effects; Population Density; Population Dynamics; Pyrethrins - toxicity; Pyrethroids; recovery; Seasons; seizoenen; sloten; Spring; Statistical analysis; Summer; surface water; toxiciteit; toxicity; Water Pollutants, Chemical - toxicity; zoetwaterecologie; zomer; Zooplankton
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-004-0249-z

The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100, 250 ng active ingredient a.i./L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately 430 L) were established using enclosures in a 50-cm-deep experimental ditch system containing communities typical of macrophyte-dominated freshwater ecosystems. Effects on macroinvertebrates, zooplankton, phytoplankton, macrophytes, and community metabolism were assessed and evaluated using univariate and multivariate statistical techniques. The macroinvertebrate community responded most clearly to treatment and, as anticipated, insects and crustaceans were among the most sensitive organisms. Statistical analysis showed that the underlying community structure was significantly different between the spring and summer experiments. However, the most sensitive species (Chaoborus obscuripes and Gammarus pulex) were abundant in spring as well as in late summer. In spring and late summer, only slight and transient effects were observed at the community level in the 10-ng/L treatment. Overall, the study did not show substantial differences in the responses of sensitive taxa between spring and late summer treatments, and effects thresholds were similar irrespective of season of treatment.