模拟雨水pH对透水砖中金属元素活化特征——以重庆市为例

Effect of Simulated Rainwater pH on Leaching Toxicity of Per vious Bricks:A Case Study of Chongqing City

在模拟不同pH降雨作用下,研究重庆地区雨水径流对透水砖中金属元素活化释放规律。结果表明,透水砖对于pH>4.00的雨水具有一定的酸缓冲能力。透水砖中Pb、As、Cr、Cu、Mn、Ni元素溶出量与雨水pH密切相关。当雨水pH=3.00时,透水砖中金属元素活性最高,对径流污染的风险最大。而Cd的溶出量最小且与雨水pH无明显关系,各元素对径流污染的风险:Cr>Cu>Ni>Mn>Zn>As>Pb>Cd。浸出液中Cd、Cr、Cu和Ni在各个pH级次均超出了地下水Ⅰ类水质限值。Cr和Cu在各个pH级次均超出地表水Ⅰ类标准限值。其中Cr在各个pH级次的溶出量均远远超出了地表水和地下水的限值要求,各元素对水体污染风险:Cr>Cu>Ni>Cd,其余元素浓度远低于标准限值,因此可忽略其影响。

Under the effect of simulating different pH rainfall,the law of activation and release of metal in permeable bricks by rainwater runoff in Chongqing was studied.The results show that the permeable brick has a certain acid buffering capacity for rainwater with pH>4.00.The amount of Pb,As,Cr,Cu,Mn and Ni dissolved in the permeable bricks is closely related to the pH of the rainwater.When the rainwater pH=3.00,the metal elements in the permeable bricks have the highest activity,and the risk of runoff pollution is the greatest.The dissolution of Cd is the smallest and has no direct relationship with the pH of rainwater.The risk of runoff pollution of various elements:Cr>Cu>Ni>Mn>Zn>As>Pb>Cd.Cd,Cr,Cu and Ni in the leachate exceeded the groundwater Class I water quality limit at each pH level.Cr and Cu exceeded the surface water Class I standard limits at each pH level.Among them,the dissolution rate of Cr in each pH grade far exceeds the limit requirements of surface water and groundwater,and the risk of water pollution of each element:Cr>Cu>Ni>Cd,the concentration of other elements is far below the standard limit,so The impact can be ignored.