A RADIOISOTOPIC STUDY OF MERCURY 

 UPTAKE BY HUDSON RIVER BIOTA 



LOIS S. ZUBARIK and JOSEPH M. O'CONNOR 



New York University Medical Center, Institute of Environmental Medicine, 



A. J. Lanza Research Laboratories, Tuxedo, New York 



ABSTRACT 



Planktonic organisms from the Hudson River were exposed to various forms of 

 mercury (^°^Hg) to evaluate the role of estuarine forage organisms in the 

 kinetics of toxic metal transport in aquatic systems. Mercury accumulation was 

 expressed as concentration per unit time. Concentration factors ranged from 10 

 to 10 times that in the filtered river water. Mercury-203 uptake was greater in 

 microzooplankton and algae than in macrozooplankton and fish larvae. The 

 amphipod Gammarus sp. was tested to determine if differences in mercury 

 uptake could be related to the form of mercury or to changes in environmental 

 conditions. Exposure to two inorganic forms of mercury (mercuric nitrate and 

 mercuric chloride) and two organic forms of mercury (methyl mercury chloride 

 and phenyl mercuric acetate) showed no differences in concentrations of the 

 four forms of mercury after a 1-day exposure. Concentration of the organic 

 forms by Gammarus sp. was three times greater than that of inorganic mercury 

 compounds after exposure for 1 week. Studies of mercury uptake throughout 

 the year showed that uptake of all the mercury compounds tested increased 

 during the summer months, but uptake of organic compounds increased to a 

 greater extent than that of inorganic compounds. Temperature change was 

 shown to be an important variable for determining the degree of uptake; 

 however, no single environmental parameter adequately explained the seasonal 

 fluctuations in mercury uptake. 



Levels of mercury in excess of 0.5 mg/liter in freshwater fish have 

 been reported in Japan (Fujiki and Fujima, 1973), Sweden (Johnels 

 and Westermark, 1969; Berglund et al., 1971), Norway (Underdal 

 and Hastein, 1971), Finland (Miettinen, 1969), the United States 

 (Wallace et al., 1971), and Canada (Bligh, 1970). Marine plankton 

 may show concentrations of mercury from 0.2 to 25 ppm dry weight 



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