Mercury residues in pintails breeding in North Dakota
Livers of 42 pintail hens ( Anas acuta ) breeding in eastern North Dakota during the spring and early summer of 1969 and 1970 were analyzed for total mercury by the neutron activation technique. Mercury content on a wet weight basis ranged from 0.055 ppm to 9.512 ppm and averaged 0.888 ± 1.796 ppm (SD). Liver mercury levels of hens collected in early spring (prior to planting of crops) were significantly lower than those of hens taken late in the nesting season ( P < 0.01). Mercury residues among prelaying, laying, and postlaying groups collected following the onset of spring planting did not differ significantly ( P > 0.05). Albumen mercury residue was correlated with liver mercury content (r = 0.756, P < 0.05). Mercury content in livers of five wild juveniles averaged 0.123 ± 0.074 ppm.