聊城市城区水岸带土壤Hg,As含量分布特征及污染评价

为了解山东省聊城市城区水岸带土壤中Hg,As含量特征和污染状况,于2015年3月至4月采集了35个水岸带土壤样品,采用王水消解-原子荧光光度计法测定了土壤中Hg,As的含量,并对水岸带土壤Hg,As的污染状况进行了评价.结果表明:聊城市城区水岸带土壤pH值的范围为8.62~9.96,呈碱性;有机质的平均质量分数为32.57 g·kg~(-1);Hg和As的质量分数平均值分别为0.139 mg·kg~(-1)和9.56 mg·kg~(-1),各点位As含量均符合国家土壤环境质量一级标准,Hg的超标率为45.7%.As与土壤有机质呈显著正相关(p0.05).以山东省土壤元素背景值为评价标准,水岸带土壤As总体表现为轻度污染和轻微生态风险,Hg表现为重度污染和较高生态危险.

Distribution Character and Pollution Assessment of Mercury and Arsenic Concentrations in Riparian Soils of Liaocheng Urban Area

In order to understand the distribution character and pollution status of the arsenic(As) and mercury(Hg) concentrations in the riparian soil of Liaocheng urban area,a total of 35 riparian soil samples were collected from Tuhai River,Xiaoyun River and Dongchang Lake in March and April 2015.Soil samples were digested using aqua regia,and then concentrations of As and Hg were measured by atomic fluorescence spectrometry method.The pollution level and ecological risk of Hg and As in riparian soil were evaluated.The results showed that the riparian soil was alkaline,with a pH range of 8.62-9.96,and the average content of organic matter was 32.57 g·kg~(-1).The average concentrations of Hg and As were 0.139 mg·kg~(-1),9.56 mg·kg~(-1).As concentrations were all lower than the class I limit value of the environmental quality standard for soils(GB15618-1995),while Hg concentrations in45.7% of the samples exceeded its class I limit value.There were significantly positive correlations between the concentrations of As and soil organic matter content(p < 0.05).Taking the soil environmental background values of Shandong Province as the standards,the As concentrations in riparian soils were generally at low pollution level and posed light ecological risk,while the pollution of Hg concentrations were heavy and posed high ecological risk to the water environment.