Synergistic effects of temperature; oxygen and water flow on the accumulation and tissue distribution of mercury in carp (Cyprinus carpio L.)

The separate and interacting effects of three environmental parameters (temperature, oxygen concentration, water flow) on the accumulation and tissue distribution of mercury were studied with yearling carp in a continuous flow system with a concentration of 0.5 μg HgCl2L−1. All 8 combinations of two levels of each environmental factor were tested (10 and 20°C; 4.5 and 9.3 mg O2 L−1, 0 and 10 cm s−1). Four organs were assayed: gill, kidney, liver, and muscle. In all tests the accumulation was highest at low O2 concentrations. Increased water flow contributed to higher levels of mercury in all organs except kidneys. At high temperatures accumulation was increased in kidneys and livers, and decreased in gills. The combination of low O2 and water flow caused the highest accumulation in all organs. An ANOVA analysis showed that there were several synergistic interactions, especially between oxygen and water flow.