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An enriched stable‐isotope approach to determine the gill‐zinc binding properties of juvenile rainbow trout ( Oncorhynchus mykiss ) during acute zinc exposures in hard and soft waters
Author(s) -
Todd Andrew S.,
Brinkman Stephen,
Wolf Ruth E.,
Lamothe Paul J.,
Smith Kathleen S.,
Ranville James F.
Publication year - 2009
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 - 10.1897/08-252.1
Subject(s) - soft water , gill , rainbow trout , hard water , zinc , biotic ligand model , environmental chemistry , toxicity , chemistry , stable isotope ratio , zoology , ecotoxicology , biology , fishery , fish <actinopterygii> , physics , organic chemistry , quantum mechanics
Abstract The objective of the present study was to employ an enriched stable‐isotope approach to characterize Zn uptake in the gills of rainbow trout ( Oncorhynchus mykiss ) during acute Zn exposures in hard water (—‐140 mg/L as CaCO 3 ) and soft water (—‐30 mg/L as CaCO 3 ). Juvenile rainbow trout were acclimated to the test hardnesses and then exposed for up to 72 h in static exposures to a range of Zn concentrations in hard water (0–1,000 μg/L) and soft water (0–250 μg/L). To facilitate detection of new gill Zn from endogenous gill Zn, the exposure media was significantly enriched with 67 Zn stable isotope (89.60% vs 4.1% natural abundance). Additionally, acute Zn toxicity thresholds (96‐h median lethal concentration [LC50]) were determined experimentally through traditional, flow‐through toxicity tests in hard water (580 μg/L) and soft water (110 μg/L). Following short‐term (S3 h) exposures, significant differences in gill accumulation of Zn between hard and soft water treatments were observed at the three common concentrations (75, 150, and 250 μg/L), with soft water gills accumulating more Zn than hard water gills. Short‐term gill Zn accumulation at hard and soft water LC50s (45‐min median lethal accumulation) was similar (0.27 and 0.20 μg/g wet wt, respectively). Finally, comparison of experimental gill Zn accumulation, with accumulation predicted by the biotic ligand model, demonstrated that model output reflected short‐term (<1 h) experimental gill Zn accumulation and predicted observed differences in accumulation between hard and soft water rainbow trout gills. Our results indicate that measurable differences exist in short‐term gill Zn accumulation following acclimation and exposure in different water hardnesses and that short‐term Zn accumulation appears to be predictive of Zn acute toxicity thresholds (96‐h LC50s).