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Toxic effects of combined stressors on Daphnia pulex : Interactions between diazinon, 4‐nonylphenol, and wastewater effluent
Author(s) -
Zein Maya A.,
McElmurry Shawn P.,
Kashian Donna R.,
Savolainen Peter T.,
Pitts David K.
Publication year - 2015
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2908
Subject(s) - diazinon , daphnia pulex , nonylphenol , effluent , environmental chemistry , daphnia , pulex , wastewater , ecotoxicology , ecotoxicity , pesticide , toxicity , toxicology , chemistry , biology , environmental engineering , environmental science , ecology , crustacean , organic chemistry
Contaminant exposure in aqueous systems typically involves complex chemical mixtures. Given the large number of compounds present in the environment, it is critical to identify hazardous chemical interactions rapidly. The present study utilized a prototype for a novel high‐throughput assay to quantify behavioral changes over time to identify chemical interactions that affect toxicity. The independent and combined effects of 2 chemicals, diazinon (an insecticide) and 4‐nonylphenol (a detergent metabolite), on the swimming behavior of the freshwater crustacean Daphnia pulex were examined. Cumulative distance and change in direction were measured repeatedly via optical tracking over 90 min. Exposure to low concentrations of diazinon (0.125–2 µM) or 4‐nonylphenol (0.25–4 µM) elicited significant concentration‐ and time‐dependent effects on swimming behavior. Exposure to 0.5 µM 4‐nonylphenol alone did not significantly alter mean cumulative distance but did elicit a small, significant increase in mean angle, the measure of change in direction. When 0.5 µM 4‐nonylphenol was used in combination with diazinon (0.125–0.5 µM), it augmented the adverse impact of diazinon on the swimming behavior of Daphnia . Additionally, enhanced sensitivity to diazinon was observed in animals exposed to treated wastewater effluent for 24 h prior to a diazinon challenge. The present experiments demonstrate that exposure to 4‐nonylphenol and complex chemical mixtures (e.g., treated wastewater) can enhance the toxicity of exposure to the insecticide diazinon. Environ Toxicol Chem 2015;34:1145–1153. © 2015 SETAC