title: Responses of aquatic invertebrates to a linear alcohol ethoxylate surfactant in stream mesocosms.
abstract: Responses of aquatic invertebrates to 30-day exposures to a nonionic linear alcohol ethoxylate (LAE) surfactant (C12-13AE-6.5) were evaluated in 10 outdoor stream mesocosms. Responses were measured as changes in invertebrate densities and invertebrate drift densities during a 14-day pretreatment period, a 30-day treatment period, and a 14-day posttreatment period relative to untreated control stream densities. Mean measured surfactant concentrations in duplicate streams were 0.32, 0.88, 1.99, and 5.15 mg LAE/liter, with two streams serving as untreated controls. Statistically significant effects were observed on simulid, copepod, and cladoceran population densities during the treatment period. Based on these effects, the no-observed-effect concentration (NOEC) for invertebrate densities was <0.32 mg LAE/liter and the lowest-observed-effect concentration (LOEC) was 0.32 mg LAE/liter. No statistically significant differences due to treatment were detected in drifting invertebrates; however, a trend was observed with increased numbers of invertebrates drifting in the streams treated with 5.15 mg LAE/liter as compared with controls.
authors.affiliation: Department of Biology, University of Mississippi, Mississippi, 38677, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Gillespie
authors.forename: J H
authors.initials: JH
authors.lastname: Rodgers
authors.forename: P B
authors.initials: PB
authors.lastname: Dorn
mesh_terms: D000438:Alcohols / Q000009:adverse effects*; D000704:Analysis of Variance; D000818:Animals; D017753:Ecosystem; D005026:Ethylene Glycols / Q000009:adverse effects*; D005618:Fresh Water / Q000737:chemistry*; D007448:Invertebrates / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000009:adverse effects*
chemical_list: D000438:Alcohols; D005026:Ethylene Glycols; D014874:Water Pollutants, Chemical