PARENT SESSION

PH08 Metals in the Environment: Aquatic Biological Perspectives
Exhibit Hall
8:00 AM - Thursday

(PH093) Acute and chronic toxicity of three metals to mottled sculpin and rainbow trout.

Besser, J¹, Ivey, C¹, Kunz, J, Greer, I¹, Ingersoll, C¹, Mount, D², Stephan, C², ¹ U.S. Geological Survey, Columbia, MO, 65201² U.S. Environmental Protection Agency, Duluthj, MN, USA

ABSTRACT- Streams inhabited by sculpins (Cottus spp.) have been affected by metal pollution from mining activities, but the sensitivity of sculpins to toxic effects of metals has been little studied. We compared the sensitivity of mottled sculpin (C. bairdi) and rainbow trout (Onchorhynchus mykiss) to toxic effects of zinc, copper, and cadmium in moderately hard water (hardness=100 mg/L). We conducted acute (96-hr) and early-life-stage chronic (21- to 28-d) toxicity tests under identical test conditions with rainbow trout and with mottled sculpins from two source populations (Minnesota and Missouri). Acute lethality was the predominant toxic effect of all three metals on both fish species, with little mortality occurring after 96 hr and no significant reductions in growth at concentrations less than those affecting survival. Acute toxicity of metals to sculpins differed widely among life stages. Toxicity of all three metals was consistently greater for newly-hatched or swim-up ssculpins than for juveniles or yearlings. Metal toxicity also differed between sculpins from the two source populations. In the most extreme example, copper was much more toxic to Missouri sculpins (average LC50=7.5 g/L) than to either Minnesota sculpins (average LC50=64 g/L) or rainbow trout (average LC50=62 g/L). For cadmium and zinc, average LC50s for one or both source populations were less than average LC50s for trout. Overall, mottled sculpins were as sensitive as or more sensitive than rainbow trout to acute toxic effects of all three metals. Species mean LC50s for toxicity of all three metals to mottled sculpins were within a factor of two of current acute water quality criteria, indicating that mottled sculpin are highly sensitive to acute toxicity of zinc, copper and cadmium.

Key words: toxicity, metals, sculpin, trout