The effects of temperature on nickel bioaccumulation and toxicity to the freshwater snail, Lymnaea stagnalis
University of New Brunswick
Lymnaea stagnalis has been reported as the most sensitive freshwater species tested to date to chronic nickel (Ni) exposure. However, a wide range of Ni toxicity values have been observed for this species, in tests conducted at various temperatures from 18 to 26°C. This variability may be partially due to temperature effects on Ni bioaccumulation and toxicity. This research investigates temperature effects on chronic Ni bioaccumulation and toxicity to L. stagnalis. I assessed the effects of temperature and Ni on juvenile growth and survival over a 40-day toxicity test, and on Ni uptake and elimination rates in short-term tests. I observed an effect of temperature on juvenile growth and survival, with an optimum temperature of 27°C. Acute Ni toxicity was significantly exacerbated by an increase in temperature between 22 and 26°C, although this temperature change had limited effects on short-term Ni uptake and elimination rates, long-term bioaccumulation, and Ni-induced growth inhibition. Our results demonstrate that toxicity tests conducted at warmer temperatures may over-estimate Ni toxicity at colder temperatures, while guidelines based on those ran at 20°C may not be protective for snails exposed at higher temperatures.