The effect of short-term exposure to pentachlorophenol and osmotic stress on the free amino acid pool of the freshwater amphipod Gammarus pseudolimnaeus Bousfield

The effects of acute stressors on the concentration of free amino acids (FAA) in the freshwater amphipod Gammarus pseudolimnaeus was investigated. Forty-eight hours of exposure to acutely toxic concentrations of pentachlorophenol resulted in a decrease in the total FAA pool at the greater concentrations and a change in the FAA profile at the lesser concentration. Hyperosmotic conditions did not alter the FAA concentrations while hypoosmotic conditions caused a decrease in the total FAA pool. Pentachlorophenol exposure did not impair the ability of amphipods to resist hypoosmotic conditions; , osmotic stress did influence the organisms ability to recover from toxicant exposure, as measured by changes in concentration of FAA. The alteration in the concentration of total FAA in stressed amphipods is probably related to a disruption in osmoregulatory ability. Changes in the FAA pool has potential as in in-situ biochemical indicator of toxicant-induced stress in freshwater invertebrates.