牛组织重金属含量与饲养环境的相关性

通过选择不同污染程度的区域进行取样,分析了贵州地区不同污染水平下牛组织中重金属(Cu、Zn、Pb、Cd)的含量和与饲养环境的相关性.结果表明:贵州不同污染水平下牛组织中的Cu、Zn基本符合国家食品卫生要求,Pb只有污染地区的肝脏和肾脏超过限量标准,Cd污染较严重,除非污染区肝脏外,牛肾脏和肝脏中Cd的平均含量均超过国家肉类制品卫生限量标准,但肌肉组织符合卫生标准;牛组织重金属元素含量与饲养环境中的土壤、饲料和饮用水源的重金属含量和污染程度密切相关,尤其是肾脏组织,其相关系数r＞0.78.饲料向牛组织的重金属迁移系数,随饲料元素含量的增加而逐渐降低,其中Cd的迁移系数最大,Pb的迁移系数最低;必需元素和有害元素在不同组织中的比值,随污染程度的增加而降低.肾脏的Cu/Cd和Zn/Cd值比其它组织低得多,Cd主要在肾脏中蓄积,Cu主要在肝脏组织蓄积,Zn主要在肌肉和肝脏,Pb主要在肾脏和肝脏.

Correlations between heavy metals concentration in cattle tissues and rearing environment

Heavy metals pollution is a major ecological concern because of the potential of their accumulation in food chain.In this study,cattle tissues were sampled from different polluted areas of Guizhou Province to analyze their copper(Cu),zinc(Zn),lead(Pb)and cadmium(Cd)concentrations,and approach the correlations between the test heavy metals concentrations and rearing environment.The results showed that the Cu and Zn concentrations in cattle tissues were within the China National Food Safety Standard,but the Pb concentration in cattle kidney and liver was slightly over the allowable limit.The Cd concentration in cattle kidney and liver from polluted areas was 38-times and 5-times higher than the Standard,respectively,while that in cattle muscle was within the Standard limit.The heavy metals concentration in cattle tissues had a close correlation with that in soil,feed,and drinking water,and especially in cattle kidney,the correlation coefficient was >0.78.The migration coefficient of heavy metals from feed to cattle tissues decreased gradually with increasing concentration of heavy metals in feed,being the highest for Cd and the lowest for Pb.The ratios of essential elements to toxic metals in cattle tissues were decreased with increasing pollution level.Cu/Cd and Zn/Cd ratios were significantly lower in kidney than in other tissues.Cd was mainly accumulated in kidney,Cu in liver,Zn in muscle and liver,and Pb in kidney and liver.It was suggested that Cd pollution was the major concern in rearing environment,and kidney was the major tissue of heavy metals accumulation.