Effects of Chlorpyrifos, Carbendazim, and Linuron on the Ecology of a Small Indoor Aquatic Microcosm

Abstract

Abstract. 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.Microcosms and mesocosms have often been used as a highertier study for the ecologic risk assessment of pesticides. They provide a bridge between laboratory and the field in terms of being manageable and allowing replication; hence, they provide a robust experimental design as well as realism in terms of ecologic processes and exposure to the chemical(s) being studied (Brock et al. 2000a).In recent years, the question of scale in ecologic studies has been widely recognized as a critical issue and underpins conceptual frameworks of how we understand ecologic phenomena (Flemer et al. 1997). Larger and consequently more complex model-ecosystems are not necessarily preferable over smaller ones. A research question can only be solved if the dimensions of the test system meet the requirements needed to solve this question. Larger and consequently more complex model ecosystems are ecologically more realistic than smaller systems. In contrast, smaller model ecosystems are easier to replicate and manipulate; therefore, they prove to be more useful in elucidating the chain of events occurring after chemical stress than large test-systems (Leeuwangh et al. 1994).The development of reliable, validated, more cost-effective, smaller test systems was recommended by the European Workshop on Freshwater Field Tests (Crossland et al. 1992) and the Higher-tier Aquatic Risk Assessment for Pesticides (HARAP) workshop (Campbell et al. 1999). However, only a smal...

Direct and indirect effects of the fungicide azoxystrobin in outdoor brackish water microcosms

“…Cairns, 1986, Taub, 1997, Giddings et al, 2002, Daam and van den Brink, 2007. The model communities presented here are reasonably simple, yet with a relatively high ecological realism compared to single species tests, or aquatic microcosms without the sediment compartment.…”

Fate in the Environment and Long-Range Atmospheric Transport of the Organophosphorus Insecticide, Chlorpyrifos and Its Oxon

“…A number of reports have noted relatively rapid dissipation of CPY in microcosms. DT 50dis of 9.6-6.1 d in microcosms treated with 0.005-5 μg L −1 were reported in small laboratory-based studies conducted in mesocosms in the Netherlands (Daam and Van den Brink 2007). However, smaller DT 50dis values (<4 d) were reported for outdoor mesocosms treated with 1 μg L −1 in Thailand (Daam et al 2008).…”

Determination of Carbendazim and Chlorpyrifos in Selected Fruits and Vegetables Samples Using QuEChERS-HPLC-FD

“…Structures of carbendazim and chlorpyrifos spectra revealed that chlorpyrifos causes the quenching of the fluorescence emission of serum albumin which determined at (λex: 275nm and λem: 350nm) as reported by Han et al [17]. A numerous publications and research papers focus on separation methods to detect carbendazim and chlorpyrifos for simultaneous determination using RP-HPLC-UV/Vis [23,25] and LC-MS-MS [7]. The aim of this study was to develop a simple, a reliable, a sensitive, a selective and an affordable technique to test the presence of carbendazim and chlorpyrifos in selected fresh samples of (appel, grapefruit, tangerine, spinach and parsley) which grown in Turkey by QuEChERS-HPLC-FD analysis without any derivatization.…”