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Toxic effects of chemical dispersant Corexit 9500 on water flea Daphnia magna
Author(s) -
Toyota Kenji,
McNabb Nicole A.,
Spyropoulos Demetri D.,
Iguchi Taisen,
Kohno Satomi
Publication year - 2017
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.3343
Subject(s) - daphnia magna , dispersant , flea , environmental chemistry , daphnia , chemistry , chemical toxicity , toxicity , toxicology , biology , water pollutants , zoology , ecology , dispersion (optics) , zooplankton , physics , organic chemistry , optics
In 2010, approximately 2.1 million gallons of chemical dispersants, mainly Corexit 9500, were applied in the Gulf of Mexico to prevent the oil slick from reaching shorelines and to accelerate biodegradation of oil during the Deepwater Horizon oil spill. Recent studies have revealed toxic effects of Corexit 9500 on marine microzooplankton that play important roles in food chains in marine ecosystems. However, there is still little known about the toxic effects of Corexit 9500 on freshwater zooplankton, even though oil spills do occur in freshwater and chemical dispersants may be used in response to these spills. The cladoceran crustacean, water flea Daphnia magna , is a well‐established model species for various toxicological tests, including detection of juvenile hormone‐like activity in test compounds. In this study, we conducted laboratory experiments to investigate the acute and chronic toxicity of Corexit 9500 using D. magna . The acute toxicity test was conducted according to OECD TG202 and the 48 h EC 50 was 1.31 ppm (CIs 0.99–1.64 ppm). The reproductive chronic toxicity test was performed following OECD TG211 ANNEX 7 and 21 days LOEC and NOEC values were 4.0 and 2.0 ppm, respectively. These results indicate that Corexit 9500 has toxic effects on daphnids, particularly during the neonatal developmental stage, which is consistent with marine zooplankton results, whereas juvenile hormone‐like activity was not identified. Therefore, our findings of the adverse effects of Corexit 9500 on daphnids suggest that application of this type of chemical dispersant may have catastrophic impacts on freshwater ecosystems by disrupting the key food chain network. Copyright © 2016 John Wiley & Sons, Ltd.