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A comparison of chronic cadmium effects on Hyalella azteca in effluent‐dominated stream mesocosms to similar laboratory exposures in effluent and reconstituted hard water
Author(s) -
Stanley Jacob K.,
Brooks Bryan W.,
La Point Thomas W.
Publication year - 2005
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 - 10.1897/04-042r.1
Subject(s) - hyalella azteca , mesocosm , effluent , environmental chemistry , cadmium , bioaccumulation , ceriodaphnia dubia , environmental science , ecology , biology , chemistry , cladocera , environmental engineering , ecosystem , amphipoda , zooplankton , organic chemistry , crustacean
Laboratory single‐species toxicity testsare used to assess the effects of contaminants onaquaticbiota. Questions remain as to how accurately these toxicity tests predict site‐specific bioavailability and chronic effects of metals, particularly in streams that are effluent‐dominated or dependent on effluent discharge for flow. Concurrent 42‐d Hyalella azteca exposures were performed with cadmium and final treated municipal effluent in the laboratory and at the University of North Texas Stream Research Facility (Denton, TX, USA), a series of outdoor lotic mesocosms. An additional 42‐d laboratory test was conducted with H. azteca to evaluate Cd toxicity in reconstituted hard water (RHW). Endpoints included Cd body burden, survival, growth, and reproduction. Calculated average bioaccumulation factors were: 2,581 (stream mesocosm test) < 3,626 (laboratory effluent) < 7,382 (laboratory RHW). The 42‐d survival lowest‐observed‐effect concentrations (LOECs) were 0.94, 4.53, and 22.97 μg/L for the laboratory RHW, laboratory effluent, and stream mesocosm exposures, respectively. Baseline growth (dry wt) and reproduction (young female −1 ) among the three exposures followed the relationship: Stream mesocosms > laboratory effluent > laboratory RHW. Differences among response variables in the three tests likely resulted from increased food sources and decreased Cd bioavailability in lotic mesocosms. Our results demonstrate that laboratory toxicity tests may overestimate chronic toxicity responses of H. azteca to Cd in effluent‐dominated streams.