302 HARRISON AND RICE 



Drifmeyer, 1974; Okazaki, 1976) and are harvested commercially in 

 large numbers as an important shellfish consumed by man. 



Although a considerable amount of information exists on 

 quantities of copper in oysters from pristine and polluted waters 

 (Brooks and Rumsby, 1965; Establier, 1972; Windom and Smith, 

 1972; Thrower and Eustace, 1973; Estabher and Pascual, 1974; 

 Ayling, 1974; Boyden and Romeril, 1974; Cronin et al., 1974; 

 Ratkowsky et al., 1974; Huggett, Cross, and Bender, 1975; Mackay 

 et al., 1975; Frazier, 1975; 1976), very little data are available on the 

 sensitivity or accumulation rates of copper in the adult oyster. 

 Previously reported LC5 values at 96 hr range from 500 to 1900 ng 

 Cu/liter (Galtsoff, 1932; Fujiya, 1960; Okazaki, 1976). Neither 

 Galtsoff nor Fujiya determined the concentrations and chemical 

 forms of copper to which the oysters were exposed; Okazaki 

 analyzed the bioassay water for total copper in his experiments. 



Our studies were initiated to determine the effects on oysters of 

 increased levels of copper in water. Under controlled laboratory 

 conditions we determined the effects on mortality rates, on copper 

 levels in the soft tissues, and on accumulation rates and tissue 

 distributions of ^"^Cu. Amounts and major chemical forms of copper 

 in the bioassay waters and amounts of copper in the oysters were 

 measured. 



MATERIAL AND METHODS 



Experimental Population 



Oysters, Crassostrea gigas, were obtained from the Coast Oyster 

 Company beds in Areata Bay, the shallow north arm of Humboldt 

 Bay, Calif. They were shipped by air to San Francisco, transported 

 immediately by truck to Lawrence Livermore Laboratory, and then 

 maintained for 7 to 10 days in a 10,000-gal recirculating seawater 

 system before testing. Water in this system was continuously 

 refiltered and was kept between 10 and 12°C by refrigeration. The 

 water for the bioassay system was collected before the experiment 

 and stored in a 10,000-gal underground tank. Water in the circulating 

 system and in the storage tank was obtained from the University of 

 California Marine Station at Bodega Bay, Calif. This water is pumped 

 from the sea off the open coast in an area that receives little 

 anthropogenic input. The water contains low levels of trace metals, 

 dissolved organics, and particulate material. Although the oysters 

 were reported to be 3 years old, they varied considerably in size. Soft 



