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Fate and effects of the herbicide atrazine in flow‐through wetland mesocosms
Author(s) -
Detenbeck Naomi E.,
Hermanutz Roger,
Allen Kathleen,
Swift Michael C.
Publication year - 1996
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.5620150616
Subject(s) - periphyton , atrazine , ceratophyllum demersum , macrophyte , zoology , mesocosm , agronomy , biology , nutrient , aquatic plant , environmental chemistry , ecology , chemistry , biomass (ecology) , pesticide
Wetland mesocosms were exposed to increasing concentrations of atrazine over time at levels typical of midwestern surface waters following spring runoff (15 to 75 μg/L). Atrazine had a half‐life of 8 to 14 d in the 230‐m‐long wetlands. End points measured included nutrient levels; periphyton biomass; periphyton productivity and respiration; growth of selected macrophytes; and survival and growth of Daphnia magna (15, 25 μg/L atrazine), Rana pipiens (15, 25 μg/L), and Pimephales promelas larvae (25 to 75 μg/L) and adults (50, 75 μg/L). Interaction between nutrient status or grazing intensity and atrazine effects were measured using periphyton enrichment and grazing exclosure experiments. Only periphyton, Ceratophyllum demersum, Zizania aquatica , and Daphnia were significantly affected by atrazine at any of the concentrations tested. Periphyton net productivity was significantly depressed by incubation in treated water as compared to control water at ≥25 μg/L atrazine (9 to 27‐d exposures). In response, dissolved nutrient concentrations increased in treated mesocosms after 14 d. Ceratophyllum length/weight ratios increased after 6‐d exposures to 50 μg/L atrazine, while Zizania senesced prematurely during treatments of 50 or 75 μg/L atrazine (97 d of cumulative exposure). Periphyton developed resistance to atrazine only at concentrations ≥50 μg/L. Atrazine effects on periphyton composition varied with the N:P supply ratio. Daphnia survival was significantly depressed at 15 μg/L atrazine (48‐h exposures).