Selenium and Other Trace Elements in Wild Larval Razorback Suckers from the Green River, Utah;Final rept

摘要

Contaminant investigations of the middle Green River, Utah, have documented selenium contamination at sites receiving irrigation drainage. The middle Green River provides critical habitat for four endangered fishes including the largest extant riverine population of endangered razorback sucker. Although 2,175 larval razorback suckers were collected from the river between 1992 and 1996, very few juveniles have been captured within recent decades. Selenium concentrations were measured in larval razorback suckers collected from five sites in the middle Green River to assess the potential for adverse effects on recruitment of larvae to the juvenile stage and the adult population. Larvae from all sites contained selenium concentrations at or above the proposed toxic threshold of 4 ug/g for adverse biological effects in fish, derived from several laboratory and field studies with a wide range of fish species. At two sites, Cliff Creek and Stewart Lake Drain, selenium concentrations in larvae increased over time as fish grew, whereas selenium concentrations decreased as fish grew at Sportsmans Drain. Evaluation of a 279-larvae composite analyzed for 61 elements demonstrated that selenium, and to a lesser extent vanadium, were elevated to concentrations reported to be toxic to a wide range of fish species.