Structural Changes in a Macrozoobenthos Assemblage After Imidacloprid Pulses in Aquatic Field-Based Microcosms
A field-based microcosm experiment was performed to investigate the effects of repeated pulses of the neonicotinoid insecticide imidacloprid on a lentic benthos assemblage. This specific microcosm method was chosen because it allows for both testing of a wide range of organisms under natural conditi...
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Published in | Archives of environmental contamination and toxicology Vol. 65; no. 4; pp. 683 - 692 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Boston
Springer US
01.11.2013
Springer Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | A field-based microcosm experiment was performed to investigate the effects of repeated pulses of the neonicotinoid insecticide imidacloprid on a lentic benthos assemblage. This specific microcosm method was chosen because it allows for both testing of a wide range of organisms under natural conditions and as well as gaining insight into intraspecific and interspecific interactions. The macrozoobenthos that colonised the microcosms was exposed to three pulses each 1 week apart at nominal concentrations ranging from 0.6 to 40 μg/L. Imidacloprid underwent fast aqueous photolysis due to optimal sunlight conditions during the test phase (half-life = 28 ± 8 h [monitored for 21 days]). Nonetheless, decreased abundance and emergence of Ephemeroptera and decreased survival of chironomid species of the subfamilies Tanypodinae and Orthocladiinae were observed at time-weighted average concentrations of 2.3 μg/L. In contrast, the gastropod
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sp. became dominant at high imidacloprid concentrations, probably due to decreased competition for food with sensitive species. The results of this study show that repeated short-term contamination of imidacloprid at low concentration levels may affect aquatic ecosystems even under optimal conditions for photodegradation. The microcosm approach, with its simple and field-relevant design, proved to be a useful tool for assessing the effects of imidacloprid contamination. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0090-4341 1432-0703 |
DOI: | 10.1007/s00244-013-9940-2 |