Toxicity and bioaccumulation of tributyltin in Hyalella azteca from freshwater harbour sediments in the Great Lakes Basin, Canada

Abstract

This study was designed to evaluate the risk that tributyltin (TBT) levels in harbour sediments pose to the freshwater invertebrate Hyalella azteca and to rank TBT as an environmental concern compared with inorganic metal species. Four-week toxicity tests and 2-week bioaccumulation tests were conducted with sediments collected from five harbours historically contaminated with TBT: Montreal, Kingston, Toronto, Hamilton, and Port Weller. While there was no observable effect of TBT on survival or growth of H. azteca, bioaccumulation of TBT exceeded levels expected to cause chronic toxicity in some sediments from Kingston, Montreal, and Port Weller. There was a positive relationship between TBT in H. azteca and TBT in sediments (r2 = 0.72), although TBT in field sediments was less bioavailable than in laboratory-spiked sediments. Body concentrations of arsenic, cadmium, chromium, cobalt, lead, manganese, nickel, and thallium were well below levels expected to cause toxicity in H. azteca. However, overlying water concentrations of copper and zinc approached or exceeded levels of concern in Toronto, Hamilton, and Port Weller sediments. This research suggests that levels of TBT in harbour sediments may cause chronic toxicity to H. azteca and freshwater invertebrate species of similar sensitivity and that copper and zinc also pose a risk at these sites.