Objective The present paper makes attempt to study the enrichment features of mercury in freshwater fishes and to evaluate the mercury contamination in environment with the fishes.Methods The fish samples of silver carp,common carp,johnny carp,shorthead catfish and catfish were collected from Songhua River and Heilongjiang River.The content of mercury in freshwater fishes,water and sediment was determined,the biological characteristic of mercury contamination in aquatic animal and the applicability of mercury contamination in aquatic amimal and its estimation were analyzed in Sep.,2007.Results The levels of mercury in river water and sediment were 0.053 ?g/L and 0.27 mg/kg for samples collected from Jiamusi section of Songhua River,and 0.034 ?g/L and 0.16 mg/kg for samples collected from Fuyuan section of Heilongjiang River.The concentrations of total mercury in the muscles of Songhua River’s silver carp,common carp,johnny carp,shorthead catfish and catfish was(0.070 ? 0.036),(0.120?0.071),(0.113?0.067),(0.152?0.107) and(0.196?0.095) mg/kg respectively.The concentrations of total mercury in the muscles of Heilongjiang River ’s silver carp,common carp,johnny carp,shorthead catfish and catfish was(0.042 ? 0.034),(0.103?0.077),(0.095?0.072),(0.157?0.118),(0.174?0.101) mg/kg respectively.The mercury content in fish in the same water environment was significantly positive correlated with its weight(P

Objective To establish a sensitive, reliable and simple method for determination of selenium(Se) in salt. Methods The salt samples were dissolved in water and added hydrochloric acid, thiourea, placed for 30 minutes under the room temperature, then used HG-AFS to determine Se. Results The linear range was 0.5-20 ?g/L, the detection limit was 0.06 ?g/L, RSD