鄂尔多斯国家级自然保护区水鸟体内重金属的组织分布及潜在来源

Tissue Distribution and Potential Sources of Heavy Metals in Waterbirds in Ordos National Nature Reserve

水鸟通常栖息在湿地,属于食物链中的高级消费者,重金属很容易在水鸟体内积累。为了解鄂尔多斯国家级自然保护区水鸟体内的重金属累积、分布特征及其潜在来源,评估潜在毒性,对鄂尔多斯保护区水鸟体内不同组织(肌肉、肝脏和肾脏)中的重金属锌(Zn)、铜(Cu)、铅(Pb)、镉(Cd)和锰(Mn)含量进行分析。采用多元分析方法解析重金属潜在来源,使用毒性阈值评估重金属的潜在毒性。结果表明:(1)各重金属平均含量为Zn(79.73 mg·kg^(-1))(以干质量计,下同)>Cu(35.80 mg·kg^(-1))>Mn(5.64 mg·kg^(-1))>Cd(2.5 mg·kg^(-1))>Pb(0.75 mg·kg^(-1)),其主要累积器官是肝脏和肾脏;水鸟中Zn、Cu和Mn含量存在显著的种间差异(P<0.05);不同重金属在水鸟组织中的分布特征存在较大差异;(2)究其来源,水鸟体内的Zn、Cu和Mn可能与工业生产和农业活动的输入有关;Cd和Pb可能与农业活动(包括耕植施肥、畜牧养殖)的输入有关;(3)Cd是本研究中浓度超过毒性阈值的单一元素,对该保护区水鸟存在潜在毒性。因此,为降低该保护区中重金属带来的潜在健康危害,应加强对Cd的防控治理。

Waterbirds are usually inhabiting wetlands,and are generally at the top of the food chain,which led to readily accumulating heavy metals through food chain.To investigate the accumulation and potential toxicities of heavy metals in waterbirds in Ordos National Nature Reserve,the distribution characteristics and the potential sources of the heavy metals,including zinc(Zn),copper(Cu),lead(Pb),cadmium(Cd),and manganese(Mn),in different tissues(i.e.muscle,liver,and kidney)of waterbirds were analyzed.Multivariate analysis was performed to analyze the potential sources of heavy metals,and toxicity thresholds were applied to evaluate their potential toxici-ty.Consequently,(1)the average levels of the heavy metals followed an order as:Zn(79.73 mg·kg^(-1))>Cu(35.80 mg·kg^(-1))>Mn(5.64 mg·kg^(-1))>Cd(2.5 mg·kg^(-1))>Pb(0.75 mg·kg^(-1)),and heavy metals were preferential accu-mulated in the liver and the kidney of waterbirds.A significant interspecific difference was found for levels of Zn,Cu,and Mn among waterfowls(P<0.05).The distribution characteristics of different heavy metals in the tissues of waterbirds varied greatly.(2)the sources of Zn,Cu,and Mn in waterbirds may be related to the emissions of them from the nearby industrial productions and agricultural activities,while the sources of Cd and Pb may be related to the pollutions from the agricultural activities(including cultivation,fertilization and livestock breeding).(3)Cd was the only element with concentration exceeding the toxicity threshold in this study and was potentially toxic to waterbirds in this reserve area.Therefore,in order to reduce the potential health hazards caused by heavy metals in this area,the prevention and control system for Cd should be established.