典型平原地区生活垃圾焚烧厂周边土壤重金属赋存形态分布特征及生物有效性评价

为考察并掌握典型平原地区生活垃圾焚烧厂周边土壤中重金属Cd、Cr、Cu、Pb、Ni和Zn的污染现状,以上海市某生活垃圾焚烧厂为例,研究其周边土壤中重金属赋存形态分布特征及生物有效性,采用Tessier连续提取法结合电感耦合等离子体发射光谱检测分析表层土壤中目标重金属总量及形态分布,并利用风险评估编码法（RAC）评价其生态风险水平.结果表明:研究区域土壤中Pb和Zn主要以Fe-Mn氧化物结合态和残渣态为主（>80%）;Cr、Cu和Ni则以残渣态为主（>60%）;Cd虽以残渣态为主（>50%）,但与其他重金属相比,其碳酸盐结合态占比相对较高.生物有效性分析结果显示,Cr、Cu和Ni以惰性态为主,生物有效性低,而潜在可利用态Cd、Pb和Zn占比较高,存在较高的释放风险.土壤中各重金属潜在生态风险水平由高到低依次为Cd > Zn > Pb > Cu > Ni > Cr,其中,Cu、Pb和Zn处于低风险水平,Cr和Ni处于无风险水平,而Cd处于中等风险水平.研究显示,该垃圾焚烧厂周边土壤中重金属已存在不同程度的污染累积,其中,潜在可利用态Cd的占比较高,已达中等风险水平,应引起重视.      

在线柱浓缩-液相色谱法测定水体中痕量敌草快和百草枯

采用在线柱浓缩-超快速液相色谱联用技术测定水体中痕量百草枯和敌草快.水样无需样品前处理,过滤后即可进样.采用固相萃取小柱富集待测物,以色谱梯度泵完成样品的净化后,利用阀切换技术将待测物反冲至分析柱进行分离,以二极管阵列检测器定量.方法在1.0—20.0μg.L-1范围内线性良好,百草枯和敌草快的线性相关系数分别为0.9997和0.9989.百草枯和敌草快的检出限(S/N=3)分别为0.10、0.12μg.L-1,加标回收率在96.0%—98.0%之间.用所建立的方法测定了水中痕量的百草枯与敌草快的含量,结果令人满意.     

Cadmium pollution enhanced ozone damage to winter wheat: biochemical and physiological evidences

Combined e ects of ozone (O3) and cadmium (Cd) on growth and physiology of winter wheat (Triticum aestivum L. cv. JM22) were determined. Wheat plants were grown without or with Cd and exposed to charcoal-filtered air (< 10 ppb O3) or elevated O3 (80 5 ppb, 7 hr/day) for 20 days. Results showed that O3 considerably depressed light saturated net photosynthetic rate (–20%), stomatal conductance (–33%), chlorophyll content (–33%), and total biomass (–29%) without Cd. The corresponding decreases were further enhanced by 45%, 56%, 60% and 59%, respectively with Cd, indicating a synergistic e ect of O3 and Cd on wheat. Ozone significantly increased the activity of superoxide dismutase (46%), catalase (48%) and peroxidase (56%). However, great increases in malondialdehyde (MDA) content (2.55 folds) and intercellular CO2 concentration (1.13 folds) were noted in O3+Cd treatment compared to control. Our findings demonstrated that the increased anti-oxidative activities in wheat plants exposed to O3+Cd might not be enough to overcome the adverse e ects of the combination of both pollutants as evidenced by further increase in MDA content, which is an important indicator of lipid peroxidation. Precise prediction model on O3 damages to crop should be conducted to ensure agricultural production security by considering environmental constraints in an agricultural system in peri-urban regions.     

Perfluoroalkyl substances in the Lingang hybrid constructed wetland,Tianjin, China: occurrence,distribution characteristics,and ecological risks

Environmental Science and Pollution Research - In this study, the occurrence, spatial distribution, sources, and ecological risks of perfluoroalkyl substances (PFASs) in the surface waters of the...