Ecotoxicity of riverbank spring water along the Hanford Reach, Columbia River

Abstract

The purpose of this study was to evaluate potential ecotoxicity of riverbank springs along the Columbia River on the Hanford site where nuclear materials were historically produced. Water samples from seven springs were collected during 1994–1995. Bioassays were conducted with Pimephales promelas (fathead minnows) for survival and growth and with Ceriodaphnia dubia (daphnids) for survival and reproduction. Synoptic chemical data were used to supplement interpretation of bioassay results. Significant decreases (p<0.05) in survival were observed for two springs in both P. promelas and C. dubia at separate locations during 1994. Significant reductions (p<0.05) in C. dubia reproduction were found for six springs in 1994 and one in 1995. A stimulatory effect (p<0.05) was also observed for this endpoint at another spring in 1995. Reproduction was the most sensitive endpoint evaluated in terms of both number of adverse effects identified and test water concentration, while growth was the least sensitive endpoint. One or more toxicological benchmarks were equaled or exceeded for all riverbank spring samples where toxicity was observed. For the contaminants evaluated, heavy metals (e.g., Cr, Cu, Ni, Zn) may have contributed to the observed toxicity. Despite limitations of employing synoptic chemical data to supplement sample characterization and extrapolating laboratory bioassay data to the field, results of this study demonstrated ecotoxicity associated with several riverbank springs, presumably reflecting contamination of groundwater on the Hanford site. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 473–480, 1999