RADIOISOTOPIC STUDY OF MERCURY UPTAKE 



283 



10 

 TIME, days 



15 



20 



Fig. 3 Long-term accumulation and loss of mercuric chloride by 

 Gammarus sp. Each point represents the mean uptake of 15 to 20 

 organisms. 



14 = 

 ORGANIC 12 — 

 CARBON lOE 

 mq/liter C 



6 



PHOSPHORUS 008 = 

 mg/liter P g g^ 



ORGANIC NITROGEN 0-8 

 mg/liter N 



SALINITY, ppt 



ALGAE CELLS/liter |= 



AMBIENT RIVER 

 TEMPERATURE, °C 



10,000 



MERCURY 

 CONCENTRATION 5,000 

 FACTOR 







Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. 



Fig. 4 Correlation between mercury concentration factors (inor- 

 ganic and organic) for Gammarus sp. and seasonal fluctuations in 

 physical and chemical parameters of Hudson River water during 

 1975. Values of R are correlation coefficients for inorganic (first 

 value given) and organic (second value) mercury concentration 

 factors with the variable graphed. Coefficients underlined are 

 significant (P < 0.005). 



A stepwise multiple regression was done to determine which 

 parameters might best explain variability in mercury uptake. 

 Ambient river temperature accounted for the largest percent of 



