Effect of temperature on heavy metal toxicity to juvenile crayfish, Orconectes immunis (Hagen)

The acute toxicity of four selected heavy metals to juvenile crayfish Orconectes immunis (Hagen) (1–2 g wet body wt. each) at room temperature increased in the following order: cadmium (×3) < copper (×10) < zinc (×2) < lead. The toxicity of these metals to crayfish acclimated at 17, 20, 23/24, and 27°C increased with temperature (by 7–20% between 20 and 24°C and 14–26% between 20 and 27°C) as judged by the lowering of LT 50 (time to kill 50% of test animals at a fixed concentration) values. A 4°C rise in temperature (from 20 to 24°C), which increased the toxicity of copper by about 7%, increased the rate of oxygen consumption by about 34%. Heavy metals inhibited the rate of oxygen consumption at all temperatures. In 20°C‐acclimated crayfish, copper caused about 17% inhibition of oxygen consumption compared to about 7–12% by other metals including the most toxic cadmium. A 3–4°C rise in temperature tripled the inhibitory effect of copper (20%), cadmium and zinc (26 and 18%, respectively), but not of lead, on oxygen consumption. A 7°C‐rise in temperature (from 20 to 27°C) increased the inhibitory effect of heavy metals, including lead, on oxygen consumption by up to 54% in the case of copper. The data indicate that rising global temperatures (currently 0.60°C) associated with climate change can have the potential to increase the sensitivity of aquatic animals to heavy metals in their environment. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 513–520, 2006.