【摘要】 研究区域为珠江三角洲一条典型城市污染河道,采集了13个站位沉积物、上覆水、间隙水及底栖动物样品进行分析.阐述了酸挥发性硫化物(acid volatile sulfide,AVS)与沉积物、上覆水、间隙水中的Cr(Ⅲ)和Cr(Ⅵ),以及寡毛纲底栖动物水丝蚓(Limnodrilus sp.)体内Cr含量的关系;围绕"Cr假设",探讨了城市重污染河道AVS与Cr的生物有效性的关系,以拓宽AVS作为沉积重金属生物毒性判据的应用范围.各站位沉积物总Cr均值为329.57 mg/kg,是背景值的9.4倍,显示研究区域属于重度Cr污染区;沉积物及上覆水Cr(Ⅵ)均较低,表明其中的铬大部分为Cr(Ⅲ).研究区域AVS较高(均值为650.38 mg/kg),间隙水总Cr含量较低(均值为68.42μg/L).除了Z1站位外,间隙水Cr(Ⅵ)均低于检出限,表明在AVS值较高的站位间隙水Cr(Ⅵ)很低.各站位水丝蚓体内总Cr含量(以DW计)为12.46~38.99 mg/kg,均值为25.85 mg/kg,高于类似研究的结果,证明水丝蚓体内Cr的积累较明显.进一步分析发现水丝蚓体内Cr含量与间隙水总Cr显著相关(r=0.614,p<0.05),因间隙水总Cr主要组分为Cr(Ⅲ),故在Cr污染严重的城市河流中,间隙水中的Cr(Ⅲ)对生物体的毒害作用不能忽视.更多还原

【Abstract】 Samples of sediment,overlying water,pore water,and benthic invertebrate were collected at 13 stations along a typical municipal polluted river in the Pearl River Delta.The samples were analyzed to study relationships between acid volatile sulfide(AVS) versus(Cr(Ⅲ)) and(Cr(Ⅵ)) in sediment,overlying water,and pore water as well as Cr in Limnodrilus sp..Based on the "Cr hypothesis",the relationship between AVS and bioavailability of Cr in heavily polluted areas was explored to extend the utility of AVS measurements as sediment assessments.The mean value of total Cr in sediment was 329.57(mg/kg),which was 9.4 times of background value(35(mg/kg)).The result indicated that the study area has been seriously polluted by Cr.The concentrations of(Cr(Ⅵ)) in sediment and overlying water were low,indicating that most of Cr was in the form of(Cr(Ⅲ)).In the study area,the value of AVS was relatively high with an average value of 650.38(mg/kg), while Cr in the pore water was low with the average of 68.42(μg/L).(Cr(Ⅵ)) in the pore water was below the detection limit except at Z1 station. The range of Cr concentrations in Limnodrilus sp.was from 12.46(mg/kg) to 38.99 (mg/kg) of dried weight,with the average of 25.85(mg/kg),which was higher than other similar results in the literature.The result showed that the amount of Cr accumulation in Limnodrilus sp.was significant.A further analysis showed a significant correlation between Cr in Limnodrilus sp.and Cr in the pore water(r=0.614,p<0.05).Since most of Cr in pore water was in the form of(Cr(Ⅲ)),the toxicity of(Cr(Ⅲ)) in pore water to organism can not be neglected in the heavily polluted river.更多还原