Environmental levels of atrazine decrease spatial aggregation in the freshwater mussel, Elliptio complanata.
The commonly used herbicide atrazine (ATR), may cause estrogen-like alterations and, like other xenoestrogens, may alter behavior. Here effects on animal aggregation were tested in freshwater mussels exposed short-term to ecologically relevant ATR concentrations between 1.5 and 150microg/L. The aggregation index (AI), the fraction of mussels in the most densely populated tank section, was evaluated and showed higher AI at later times in both 6- and 72-h trials (p<0.001). After 72h, there was also less aggregation in estradiol- and mid-ATR-treated animals, 26% and 24% less than control, respectively (p<0.04). These data suggest that freshwater mussels tend to aggregate, that 72-h exposure to ecologically relevant ATR concentrations decreases aggregation, and that estradiol exposure has a similar effect. Given that bivalve aggregation may be related to reproduction, the results suggest that low concentrations of ATR may have ecological consequences on animal populations in this species.
Flynn
Katherine
K
Department of Biology, Environmental Studies Program, Adelphi University, 1 South Avenue, Garden City, NY 11530, USA. kflynn2000@yahoo.com
Spellman
Tanya
T
D000704:Analysis of Variance; D000818:Animals; D001280:Atrazine / Q000493:pharmacokinetics / Q000633:toxicity*; D049872:Bivalvia / Q000187:drug effects / Q000254:growth & development*; D003627:Data Interpretation, Statistical; D004958:Estradiol / Q000378:metabolism; D005618:Fresh Water; D006207:Half-Life; D006540:Herbicides / Q000493:pharmacokinetics / Q000633:toxicity*
D006540:Herbicides; D004958:Estradiol; D001280:Atrazine