Effects of water chemistry variables on gill binding and acute toxicity of cadmium in rainbow trout (Oncorhynchus mykiss): A biotic ligand model (BLM) approach

Som Niyogi, Rebecca Kent, Chris M. Wood

Research output: Contribution to journalArticle

59 Scopus citations

Abstract

This study investigated the short-term (3 h) cadmium binding characteristics of the gills, as well as the influence of various water chemistry variables [calcium, magnesium, sodium, pH, alkalinity and dissolved organic carbon (DOC)] on short-term gill accumulation and acute toxicity of cadmium in juvenile freshwater rainbow trout. The cadmium binding pattern revealed two types of cadmium binding sites in the gill: (i) saturable high affinity sites operating at a low range of waterborne cadmium concentration, and (ii) non-saturable low affinity sites operating at a higher range of cadmium concentration. Among the water chemistry variables tested, only calcium and DOC significantly reduced both gill accumulation and toxicity of cadmium. Interestingly, alkalinity (15-90 mg L- 1 as CaCO3) did not influence the gill cadmium accumulation but a significant increase in toxicity was recorded at a higher alkalinity level (90 mg L- 1). Affinity constants (log K) for binding of competing cations (Cd2+ and Ca2+) to the biotic ligand and for binding of Cd2+ to DOC were derived separately from the 3 h gill binding tests and the 96 h toxicity tests. In general, the values agreed well, indicating that both tests targeted the same population of high affinity binding sites, which are likely Ca2+ uptake sites on the gills. These parameters were then incorporated into a geochemical speciation model (MINEQL+) to develop a biotic ligand model for predicting acute toxicity of cadmium in trout. The model predictions exhibited a good fit with the measured toxicity data except for high alkalinity and pH.

Original languageEnglish (US)
Pages (from-to)305-314
Number of pages10
JournalComparative Biochemistry and Physiology - C Toxicology and Pharmacology
Volume148
Issue number4
DOIs
StatePublished - Nov 2008

Keywords

  • BLM
  • Cadmium
  • Fish
  • gill-binding
  • toxicity

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Physiology
  • Health, Toxicology and Mutagenesis
  • Toxicology

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