In-situ microcosms, a tool for assessment of pesticide impacts on oyster spat (Crassostrea gigas).
Ecotoxicology
; 17(4): 235-45, 2008 May.
Article
em En
| MEDLINE
| ID: mdl-18236155
ABSTRACT
Effects of the herbicide Basamaïs (bentazon) and the fungicide Opus (epoxiconazole) on oyster spat (Crassostrea gigas) were assessed using in-situ microcosms in a field experiment lasting 13 days. Six-week-old hatchery spat (mean size 1.1 mm), previously collected on PVC plates, was immersed in glass bottles filled with 200 mum filtered seawater. Bottles were maintained underwater at 6 m depth and their water content changed every other day. Growth, measured as shell area index increase, was 126 +/- 4% in the control bottles. While no growth differences were observed between control and individual pesticide treatments at 10 microg l(-1), oysters treated with a mix of 10 microg l(-1) Opus and 10 microg l(-1) Basamaïs showed a 50% growth reduction compared with the control (P < 0.0001), suggesting a synergistic effect of these contaminants. Laboratory controls in microcosms maintained in a water bath with filtered natural light, were not significantly different from in-situ microcosm controls in the field, for organic weight content or growth. This in-situ experiment in microcosms allowed us to conclude that (1) oyster spat can achieve significant growth in bottles immersed in situ without supplementary food; (2) this microcosm system is reliable and easy to use for environmental toxicity tests with C. gigas spat; (3) such microcosm systems can also be run in a laboratory water bath instead of more technically difficult immersed field experiments; (4) the synergistic effect observed here, at a concentration simulating a peak agricultural runoff event, suggests that the impacts of pesticides could be a real threat for oysters in estuarine areas.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Triazóis
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Poluentes Químicos da Água
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Benzotiadiazinas
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Testes de Toxicidade
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Compostos de Epóxi
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Crassostrea
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Fungicidas Industriais
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Herbicidas
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
França