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The Relative Importance of Waterborne and Dietborne Arsenic Exposure on Survival and Growth of Juvenile Rainbow Trout
Citation:
ERICKSON, R. J., T. L. HIGHLAND, J. HOCKETT, AND C. T. JENSON. The Relative Importance of Waterborne and Dietborne Arsenic Exposure on Survival and Growth of Juvenile Rainbow Trout. AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 104(1-2):108-115, (2011).
Impact/Purpose:
Previous work in our laboratory demonstrated toxicity to rainbow trout fed oligochaetes contaminated with arsenic via waterborne exposure. While this demonstrated the potential hazard of dietborne exposure, it did not address the relative and combined potency of waterborne and dietborne exposure. To evaluate these issues, we exposed both rainbow trout and their oligochaete prey to a range of waterborne arsenate concentrations, and determined the effects on survival and growth after 28 d of exposure to arsenic in water, diet, or both. Waterborne exposure to arsenate at 16 or 32 mg As/L resulted in elevated mortality and substantially reduced growth. Rainbow trout fed oligochaetes exposed to 4 or 8 mg As/L in water for 7 days, showed pronounced reductions in growth in the absence of waterborne exposure, and even greater effects under simultaneous waterborne exposure. Mortality of rainbow trout in these exposures was better correlated to waterborne exposure concentration than to whole body arsenic, but growth reductions showed a strong correlation to tissue residue regardless of the route of exposure. However, the relative concentration of total arsenic in viscera versus whole body did appear diagnostic of exposure route. Speciation of arsenic showed oligochaete tissue to contain predominately arsenite rather than arsenate. Perhaps most importantly, when fish and prey were exposed to the same waterborne arsenate concentration, greater effects were induced via dietborne exposure, emphasizing the potential implications of dietborne exposure for assessing aquatic risks of arsenic contamination.
Description:
Previous work in our laboratory demonstrated toxicity to rainbow trout fed oligochaetes contaminated with arsenic via waterborne exposure. While this demonstrated the potential hazard of dietborne exposure, it did not address the relative and combined potency of waterborne and dietborne exposure. To evaluate these issues, we exposed both rainbow trout and their oligochaete prey to a range of waterborne arsenate concentrations, and determined the effects on survival and growth after 28 d of exposure to arsenic in water, diet, or both. Waterborne exposure to arsenate at 16 or 32 mg As/L resulted in elevated mortality and substantially reduced growth. Rainbow trout fed oligochaetes exposed to 4 or 8 mg As/L in water for 7 days, showed pronounced reductions in growth in the absence of waterborne exposure, and even greater effects under simultaneous waterborne exposure. Mortality of rainbow trout in these exposures was better correlated to waterborne exposure concentration than to whole body arsenic, but growth reductions showed a strong correlation to tissue residue regardless of the route of exposure. However, the relative concentration of total arsenic in viscera versus whole body did appear diagnostic of exposure route. Speciation of arsenic showed oligochaete tissue to contain predominately arsenite rather than arsenate. Perhaps most importantly, when fish and prey were exposed to the same waterborne arsenate concentration, greater effects were induced via dietborne exposure, emphasizing the potential implications of dietborne exposure for assessing aquatic risks of arsenic contamination.