Radiotracer studies on waterborne copper uptake, distribution, and toxicity in rainbow trout and yellow perch: a comparative analysis
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Date
2008
Authors
Pyle, Gregory
Wood, Chris M.
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis
Abstract
Rainbow trout (Oncorhynchus mykiss) are often used to estimate important biotic
ligand model (BLM) parameters, such as metal-binding affinity (log K) and capacity
(Bmax). However, rainbow trout do not typically occupy metal-contaminated environments,
whereas yellow perch (Perca flavescens) are ubiquitous throughout most
of North America. This study demonstrates that dynamic processes that regulate
Cu uptake at the gill differ between rainbow trout and yellow perch. Rainbow trout
were more sensitive to acute aqueous Cu than yellow perch, and toxicity was exacerbated
in soft water relative to similar exposures in hard water. Whole body Na
loss rate could account for acute Cu toxicity in both species, as opposed to new
Cu uptake rate that was not as predictive. Time course experiments using radiolabelled
Cu (64Cu) revealed that branchial Cu uptake was rather variable within the
first 12 h of exposure, and appeared to be a function of Cu concentration, water
hardness, and fish species. After 12 h, new branchial Cu concentrations stabilized
in both species, suggesting that metal exposures used to estimate BLM parameters
should be increased in duration from 3 h to 12+ h. In rainbow trout, 71% of the
new Cu bound to the gill was exchangeable (i.e., able to either enter the fish or be
released back to the water), as opposed to only 48% in yellow perch. This suggests
that at equal exposure concentrations, proportionally more branchial Cu can be
taken up by rainbow trout than yellow perch, which can then go on to confer toxicity.
These qualitative differences in branchial Cu handling between the two species
emphasize the need to develop BLM parameters for each species of interest, rather
than the current practice of extrapolating BLM results derived from rainbow trout
(or other laboratory-reared species) to other species. Data reported here indicate
that a one-size-fits-all approach to predictive modeling, mostly based on rainbow
trout studies, may not suffice for making predictions about metal toxicity to yellow
perch—that is, a species that inhabits metal-contaminated lakes around northern
Canadian industrial operations.
Description
Sherpa Romeo green journal
Keywords
Biotic ligand model , Copper , Species differences , Exchangeable fraction , Metal-gill binding dynamics , Acute toxicity
Citation
Pyle, G.G. and C.M. Wood. 2008. Radiotracer studies on waterborne copper uptake, distribution, and toxicity in rainbow trout and yellow perch: a comparative analysis. Human and Ecological Risk Assessment, 14: 1-23. Invited contribution.