贵州草海湿地水鸟重金属暴露风险评估与应用

运用综合暴露风险模型评价贵州草海湿地水鸟群落的重金属暴露风险，并通过反距离权重插值法和图层叠加分析确定暴露风险的空间分布.结果表明，草海水鸟栖息地土壤中As、Cd、Cr、Ni、Pb、Zn的均值含量均超过贵州的土壤背景值，As、Cd、Cr、Pb、Zn在浅水沼泽、草地、耕地和水沟4种生境植物中均呈污染水平，As、Pb在水鸟肉食性食物鱼样中超标.草海水鸟主要对Cr、Pb、Zn存在暴露风险，在不同食性水鸟食物摄入途径不同则对重金属的暴露风险不同.在不同食性的代表性水鸟中，Pb在食植途径对针尾鸭、斑头雁，在食土途径则对白鹭暴露风险最高.Cr在食土途径中对3种水鸟暴露风险都较高.而Zn主要在食肉途径对白鹭、斑头雁的暴露风险最高.综合评价表明，代表肉食性水鸟的白鹭和代表植食性的针尾鸭的重金属潜在危害风险为高风险，代表杂食性的斑头雁为中风险.以水鸟栖息区域的潜在危害风险来看，双河、胡叶林、王家院子周边和邻近威宁县城城区的区域达到了高风险水平.建议重点监测肉食性水鸟群落的健康状态，优先治理和防控Cr、Pb、Zn重金属污染物以及污染高风险区域，采取科学合理的人为活动限制和污染防控措施.

Risk assessment and application of heavy metal exposure of waterbirds in Caohai Wetland,Guizhou Province,China

A comprehensive exposure risk model was used to evaluate the heavy metal exposure risk of waterbirds in Caohai Wetland in Guizhou Province, and the spatial distribution of exposure risk was determined as well based on the inverse distance weight interpolation method and layers overlay analysis. The mean contents of As, Cd, Cr, Ni, Pb and Zn in the soil of Caohai waterbirds habitats were greater than those of the soil background values in Guizhou Province. The contents of As, Cd, Cr, Pb, and Zn were at pollution levels in the four habitat plants including grassland, ditch, shallow swamp, and cultivated land. Moreover, As and Pb in the fishes, which are diet of waterbirds in the habitats, exceeded the allowed risk standards. The exposure risks of waterbirds towards Cr, Pb and Zn varied with the foraging behaviors and ways of feeding. According to the diet-representative waterbird species habited in Caohai, Pb showed highest exposure risk to Anas acuta and Anser indicus in the plant-feeding route and to Egretta garzetta in the soil-related feeding route. Cr showed high exposure risk to three representative species of waterbirds in the soil-related feeding route. Zn mainly showed high exposure risk to Egretta garzetta and Anser indicus in the meat-related feeding route. The comprehensive assessment showed that the potential risk of heavy metal hazards toward Egretta garzetta (represented as carnivore species) and Anas acuta (represented as herbivore species) were both at high level, while that the Anser indicus (represented as omnivory species) was at moderate level. In addition, from the perspective of potential hazard risk of waterbirds habitat area, four areas such as Shuanghe, Huyelin, Wangjiayuanzhi and the surrounding area of Weining County Town have high potential risk of heavy metal pollution. Therefore, it is suggested to pay more attention on monitoring the health of carnivorous waterbird communities. Cr, Pb and Zn heavy metal pollutants and high potential pollution areas abatement should be a top priority through scientifically and reasonably measures to restrict human activities and control the pollutions near Caohai.