HEAVY METALS IN THE NORTHERN FUR SEAL, 



CALLORHINUS URSINUS, AND 



HARBOR SEAL, PHOCA VITULINA RICHARDI 



Raymond E. Anas' 



ABSTRACT 



Samples of liver, muscle, and kidney from fur seal, Callurhimts iirsimis, and liver from harbor 

 seal, Pliocu viiiilina ricliarcli, were analyzed for lotal mercury. Liver and kidney of fur seals 

 were analyzed for lead, cadmium, and arsenic. Fur seals were from the Pribilof Islands, 

 Alaska, and from off the Washington coast. Harbor seals were from the waters of southern 

 California, Oregon, Washington, and the Bering Sea. All of the samples, including a fetus 

 taken 3 mo before birth, contained mercury, lead, and cadmium. Arsenic was not detected. 

 Mercury was highest in liver, followed by kidney, then muscle. The maximum concentration 

 of mercury in liver was about 700 ppm in a southern California harbor seal and 170 ppm in 

 a fur seal taken off the Washington coast. Concentrations of cadmium and lead were highest 

 in the kidney (maximums of 1.8 ppm lead and 15.6 ppm cadmium) of fur seals. Concentra- 

 tions of mercury did not correlate with age in muscle or kidney (P> 0.05) but did correlate 

 significantly with age in liver iP < O.OI). Concentrations of cadmium and lead in liver and 

 kidney did not correlate with age (P > 0.05). In samples of liver collected from harbor seals, 

 the highest concentrations of mercury were from southern California seals. 



Heavy metals are persistent contaminants that 

 ultimately end up in the oceans. Little is known 

 of the sublethal effects of these contaminants 

 on living marine resources, but some heavy 

 metals are known to be harmful. One ppb (part 

 per billion) of four commonly used organo- 

 mercurial fungicides reduced the photosynthetic 

 rate of a marine diatom (Harriss, White, and 

 MacFarlane, 1970). Skerfving, Hansson, and 

 Lindsten (1970) reported chromosome break- 

 age in humans who ate fish containing 1-7 i)pm 

 (parts per million) methylmercury. 



Heavy metals are added to the sea by land 

 erosion, volcanic activity, and man. A committee 

 of experts selected mercury, lead, cadmium, and 

 arsenic as the four inorganic jjollutants most 

 threatening to the marine environment (Food 

 and Agriculture Organization of the United 

 Nations, 1971). The same elements were 

 selected for this study. Average levels of the 

 four most critical heavy metals in the ocean are 

 about 0.00003 ppm (mg/1) mercury, 0.08 ppm 

 cadmium, 0.00003 ppm lead, and 0.003 ppm 

 arsenic (U.S. Senate, 1970). Williams and Weiss 



(1973) found 0.00027 ppm mercury at 10-m 

 depth and 0.000029-0.000096 ppm from 100- to 

 4,080-m depth in water samples taken 430 km 

 southeast of San Diego, Calif. 



Amounts of contaminants in seals provide us 

 with data at this time in a marine species near 

 the top of the food web in the ocean. Up to 

 172 ppm mercury in liver of northern fur seals, 

 CaU(>)-}uinis in-si))t(i^ (Anas, 1970a); 66 ppm in 

 liver of gray seals, Hallchoerus gnjpi(s (Jones, 

 Jones, and Stewart, 1972); and 24 ppm mercury 

 in liver of short-finned pilot whales, Globi- 

 cephala scammo)n (Hall, Gilmailin, and 

 Mattsson, 1971) have been reported. Buhler- 

 repoited 60 ppm cadmium in the kidney, 6 ppm 

 cadmium in the liver, and 225 p])m mercury in 

 the liver of California sea lions, Zalophus 

 califnniiaHu.s. This report documents the 

 amounts of mercury, lead, cadmium, and 

 arsenic in northern fur seals and of mercury in 

 harbor seals, PJioca vitulhia richardi. 



Northern fur seals are a migratory species 

 that breed each summer mainly on the Pribilof 

 Islands, Alaska, and on the Commander Islands 



' Northwest Fisheries 

 Fisheries Service, NOAA, 

 Seattle, WA 98 112. 



Center, National Marine 

 2725 Monllake Blvd. E., 



Manuscript accepted June. 1973 



FISHERY BULLETIN: VOL. 72. NO. 1, 1974 



- D. R. Buhler. Environmental Health Sciences Center, 

 Oregon State University, Corvallis. Oregon 97331, per- 

 sonal communication. 



133 



