title: Environmental levels of atrazine decrease spatial aggregation in the freshwater mussel, Elliptio complanata.
abstract: 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.
authors.affiliation: Department of Biology, Environmental Studies Program, Adelphi University, 1 South Avenue, Garden City, NY 11530, USA. kflynn2000@yahoo.com
authors.forename: Katherine
authors.initials: K
authors.lastname: Flynn
authors.forename: Tanya
authors.initials: T
authors.lastname: Spellman
mesh_terms: 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*
chemical_list: D006540:Herbicides; D004958:Estradiol; D001280:Atrazine