鄱阳湖-乐安河湿地水土环境中重金属污染的时空分布特征

选取流域两岸富含有色金属矿产资源的乐安河及至鄱阳湖段的典型湿地区域,分别于2012年4月(平水期)、8月(丰水期)、11月(枯水期)等不同时段采集不同样点底泥、表土、上覆水等环境样品,监测分析重金属Cu、Pb、Cd的含量,并借助统计分析方法识别乐安河湿地重金属污染的时空分布特征及其来源.结果表明,乐安河流域各样点的重金属Cu含量最高,且各样点重金属的含量值均表现为Cu>Cd>Pb.以丰水期的重金属污染最严重,平水期次之,枯水期的重金属污染最轻.重金属Cu含量的高值区出现在乐安河上游;而重金属Pb含量的高值区出现在乐安河下游及入湖区域;重金属Cd的高值区出现在乐安河中游.表征重金属Cu污染的主成分贡献率为36.99%,表征重金属Cd的主成分贡献率为30.12%.底泥Cu和上覆水Cu、河滩表土Cu含量具有较强的相关性;底泥Cd和表土Cd的含量也表现出强相关性.以上结果反映出水体、底泥和土壤中的Cu污染或Cd污染的来源具有一致性,主要来源于矿山开采排放的重金属酸性污废水;而其余组分间的相关性则表现不甚明显,反映出不同污染物的来源存在一定的差异性.

Spatiotemporal Variation Characteristics of Heavy Metals Pollution in the Water, Soil and Sediments Environment of the Lean River-Poyang Lake Wetland

Overlying water, sediments, surface soils in the typical wetland areas of Lean River and Poyang Lake which were rich in non-ferrous metal mineral resources on both sides of the river, were chosen for monitoring heavy metals including copper, lead and cadmium of base flow in average season, flood season, and dry season in 2012. Statistical analysis methods were coupled to characterize the spatiotemporal variation of heavy metals pollution and identify the main sources. The results indicated that the concentrations of copper were the highest in all samples of each sampling sites in the Lean River-Poyang Lake wetland. And the content values of copper, lead and cadmium in different samples of different sampling sites also showed that the content values of copper were higher than those of lead, and the content values of lead were also higher than those of cadmium. The results also showed that the heavy metals pollution of copper, lead and cadmium in flood season was the heaviest whereas the heavy metals pollution in dry season was comparatively light. The results of the contents of the three kinds of heavy metals elements in different sampling sites of the watersheds of lean River showed that the contents of copper in the samples from the upstream sampling sites of Lean River were higher than those of other samples from other sites. And the contents of lead in the samples from the downstream sampling sites of Lean River were higher than those of other samples from other sampling sites. The contents of cadmium in the samples from the midstream sampling sites of Lean River were higher than those of other samples from other sites. The first principal component representing copper pollution explained 36.99% of the total variance of water quality. The second principal component concerning representing lead pollution explained 30.12% of the total variance. The correlation analysis results showed that there were significant positive correlations among the contents of copper in sediments and the contents of copper in overlying water. And there was also significant positive correlation between the contents of copper in sediments and the contents of copper in the surface soils. And the correlation analysis showed that there were significant positive correlations among the contents of cadmium in sediments and the contents of cadmium in surface soils. The above results reflected that the copper pollution or cadmium sources of water, soil and sediments were consistent,which were mainly from heavy metal acidic waste of mining emissions. The correlations between other components were not very obvious, which reflected the sources of pollutants were different.