|
|
|
| Safety Levels of Three Heavy Metals in Clam Scapharca broughtonii Culturing Water |
| LI Xiao,WANG Ying,WU Zhihong,LIU Tianhong,SUN Yuanqin |
|
|
|
|
Abstract The bio‐concentration and elimination of As ,Cd and Pb in the tissue of clam Scapharcabrough‐tonii were investigated in double‐boxes kinetic model in order to provide reference for aquaculture practices safety levels .A semi‐static system was maintained throughout a 35‐day exposure period in different con‐centrations of heavy metals .The aquaculture water concentrations of heavy metals were set according to the national second‐class seawater standard (GB 3097—1997) ,removing the background values in natural seawater .Then ,the test organism was transferred to clean seawater for a elimination period of 35 days . The results showed that the bio‐concentration factor (BCF) was 38 .97 for inorganic arsenic ,1029 .88 for Pb and 568 .80 for Cd .The accumulation ability order was expressed as Cd> Pb>inorganic arsenic .And the biological half‐life (B1/2 ) was 20 .5 d for inorganic arsenic ,15 .4 d for Pb and 21 .3 d for cd .In this study ,under the national second‐class seawater standard (GB 3097—1997) ,the maximal content of heavy metals in the tissue of the clam was inorganic arsenic 1 .9671 mg/kg ,Pb 2 .5946 mg/kg and Cd 7 .2222 mg/kg .Combined with the safe limit of NY 5135—2005 ,three kinds of heavy metal safety limited converted from BCF :0 .02900 mg/L in inorganic arsenic ,0 .00096 mg/L in Pb ,0 .00064 mg/L in Cd .T he findings can provide scientific basis for the safety limits of the culture water quality .
|
|
Received: 25 May 2016
|
|
|
|
|
|
|
