PARENT SESSION

IP11 Investigations of the Columbia River and Estuary (USA)
B113 & B114
8:00 AM - 12:00 PM, Thursday

(IP094) Effects of hexavalent chromium on fall Chinook salmon in the Columbia River at Hanford.

Patton, G¹, Dauble, D¹, ¹ Pacific Northwest National Laboratory, Richland, WA, 99352

ABSTRACT- We evaluated the site-specific effects for early life-stage (i.e., eyed egg to swim-up) fall Chinook salmon (Oncorhynchus tshawytscha) that might be exposed to hexavalent chromium from groundwater sources at the U.S. Department of Energy′s Hanford Site in southeastern Washington State. This study was one part of an overall effort to evaluate the potential impact of contaminated groundwater on fall Chinook salmon populations in the Hanford Reach of the Columbia River. During 1998 to 1999, the USGS and USFWS initiated a series of lab tests (surrogate groundwater and non-local salmon stocks) to evaluate the toxicity and behavior of Chinook salmon exposed to chromium during fertilization, incubation, and parr life stages. Exposure conditions for the site-specific study, initiated in 1999, were chromium-containing groundwater obtained from a Hanford source near the Columbia River, Columbia River water as the diluent, and locally adapted salmon. The exposure levels were a river water control plus 11, 24, 54, 120, and 266 g/L of hexavalent chromium. The test was conducted in a modified Mount and Brungs flow-through diluter system with temperature and photoperiod control. Specific endpoints included survival, development rate, and growth. Chromium tissue burdens of fish were measured to evaluate uptake and elimination rates. Our study showed that survival, development, and growth of early life-stage fall Chinook salmon from the eyed-egg stage to swim-up stage were not adversely affected by exposures to chromium from 11 to 266 g/L. Survival was high for all groups, exceeding 98% at termination. In addition, there were no statistically significant differences between the lengths and weights of treatment groups after 98 days of exposure. Whole-body concentrations of chromium in salmon had a typical dose-response pattern. Collectively, these data support that the current water quality criteria of 10 g/L is adequate to protect fall Chinook salmon in the Hanford Reach.

Key words: fall Chinook salmon, hexavalent chromium, Columbia River, early life stage