304 HARRISON AND RICE 



Copper Analyses of Bioassay Water 



Total and ionic copper concentrations in the bioassay water were 

 measured at 1- to 3-day intervals during the test period. Water was 

 collected either by siphoning directly from the trays over a 5-min 

 interval (grab sample) or by continuously pumping from the tray at a 

 low rate over a 2- to 3-day interval (integrated sample). Both tot£il 

 and ionic copper concentrations generally were measured in grab 

 samples, but only total copper was measured in integrated samples 

 since they were acidified to pH 1 during collection. 



Total copper in samples containing copper concentrations 

 >400 jUg/liter was determined by direct aspiration of seawater into 

 the flame of the atomic absorption spectrometer and in samples with 

 copper concentrations >10 yug/liter by direct injection into a graphite 

 furnace. 



Ionic copper, operationally defined as the fraction retained by 

 Chelex 100 resin (Bio-Rad Laboratories), was determined by the 

 method of RUey and Taylor (1968). Eluants from the columns were 

 analyzed directly in the flame or in the graphite furnace. 



Accumulation of ^'*Cu 



Groups of oysters were exposed in refrigerated aquariums to 

 ^ "* Cu-labeled seawater containing concentrations of approximately 

 1.0, 800, or 2400 /ig Cu/liter. Sixteen oysters were maintained at 

 each concentration, and four animals were sampled from each system 

 after 1, 5, 10, and 24 hr of exposure. 



The initial amount of ^"^Cu in the water at all three copper 

 concentrations was 300 pCi/liter. Standards of ^^Cu were made 

 when the isotope was added to the aquarium water. At regular 

 intervals concentrations of ^"^Cu in aquarium waters were compared 

 with the standards. Additions of ^"^Cu were made to aquarium 

 waters when the ^'*Cu level was lower than expected from decay 

 alone so that changes in the water reflected only radioactive decay. 



To prepare for ^^Cu analysis, we weighed oysters whole, 

 removed the soft tissues from the shells, and dissected them into 

 mantles, gills and labial palps, digestive glands and stomachs, gonads 

 and intestines, adductor muscles, body fluids, and remains. Each 

 tissue was weighed and counted in a gamma well counter. 



All counts of water and tissues were corrected for background 

 and counting efficiency and then for decay to the time the 

 experiment began. 



