包头市三类湿地中重金属污染程度及生物富集研究

STUDY ON POLLUTION DEGREE AND BIO-CONCENTRATION OF HEAVY METALS IN THREE TYPES OF WETLANDS IN BAOTOU, CHINA

以昆都仑水库桃儿湾湿地、小白河黄河湿地以及尾矿库南侧湿地为研究样地,以底泥、藻类、昆虫和花背蟾蜍(Bufo raddei)为研究对象,评价了湿地底泥重金属污染程度,以及重金属沿两栖类食物链(网)的富集与放大作用。结果显示:昆都仑水库桃儿湾湿地底泥中重金属未超出背景值,而小白河黄河湿地与尾矿库南侧湿地除Mn以外,其他金属含量均不同程度地超出背景值。昆都仑水库桃儿湾湿地、小白河黄河湿地和尾矿库南侧湿地底泥的污染负荷指数分别为0.35、1.56和2.54。Cu和Cr在花背蟾蜍肝脏中富集程度显著高于肌肉组织(P<0.05),且以Cu的富集系数最大。结果表明:各样地底泥重金属污染程度顺序为尾矿库南侧湿地>小白河黄河湿地>昆都仑水库桃儿湾湿地。重金属Cu和Cr易在花背蟾蜍肝脏中富集。研究成果可为当地湿地重金属污染评价及两栖类的保护提供数据支持。

This study chose the Taoerwan Wetland in Kundulun Reservoir, Yellow River Wetland in Xiaobai River, and the Wetland on the south of a tailings pond as the study sites, and took the sediments, algae, insects, and Bufo raddei as the study objects, and evaluated the pollution level of heavy metals in sediments and the bio-concentration and amplification effect of heavy metals along the amphibians’ food chain. The results showed that: the contents of heavy metals of Taoerwan Wetland in Kundulun Reservoir were below the soil background values, while all of the heavy metal contents of the Yellow River Wetland in Xiaobai River and the Wetland to the south of tailings pond exceeded the soil background values to different degrees, except for the content of Mn. The pollution load indexes of Taoerwan Wetland in Kundulun Reservoir, Yellow River Wetland in Xiaobai River, and the Wetland on the south of tailings pond were 0.35, 1.56 and 2.54, respectively. The enrichment capacities of Cu and Cr in the liver of Bufo raddei were significantly higher than that in muscular tissues(P<0.05), especially Cu had the largest enrichment coefficient. The results indicated that the pollution degree of sediments in the three wetlands was: Wetland on the south of tailings pond>Yellow River Wetland in Xiaobai River>Taoerwan Wetland in Kundulun Reservoir. Cu and Cr were easy to enrich in the liver of Bufo raddei, and this study could provide data and theoretical support for the assessment of heavy metal pollution and the protection of amphibians in the local wetlands.