基于长江三角洲地表水典型土壤铜、锌环境容量探究

我国水污染日益严重,Ⅰ类地表水地区较少,目前可供饮用的Ⅲ类水成为研究土壤地表水体系污染状况的热点。选取具有代表性的长江三角洲地区4种母质（河相、湖相、海相沉积物和沟沟堆积物）发育而成的土壤,通过加入不同量的外源铜、锌金属培育污染土样,使其分别达到国家土壤环境质量三级标准的0.25、0.5、1.0、1.5、2.0、2.5倍。在此基础上研究雨水和模拟酸雨条件下,对模拟污染的土样进行解吸,并对解吸曲线进行拟合,在基于地表水Ⅲ类水质标准的铜、锌环境容量的基础上,计算了4种土壤在不同情况下的土壤环境容量,并通过探讨国家土壤标准的吻合性,提出针对不同母质的土壤,对其重金属的土壤污染临界值进行适当的调整,以达到Ⅲ类水标准,保障人类的安全与健康。结果表明,在模拟雨水情况下,基于地表水Ⅲ类标准的4种土壤的环境容量分别为：SEBC-06：铜10002mg·kg^-1,锌848.1mg·kg^-1;SEBC-19：铜1162mg·kg^-1,锌612.9mg·kg^-1;SEBC-20：铜9796mg·kg^-1,锌1047mg·kg^-1;SEBC-25：铜720mg·kg^-1,锌180.2mg·kg^-1。

Critical Loads of Copper and Zinc in Typical Soils Based on the Surface Water in Yangtze River Delta

As increasing of serious water pollution,the class Ⅰ surface water area was becoming less,so forcusing on the class Ⅲ surface water area was becoming more and more popular because the class Ⅲ surface water could be used as drinking water. This work selected four typical soils formed from different parent materials（River sediments,Lacustrine sediments,Marine sediments and Gully deposits） in the Yangtze River Delta region,which were polluted through adding exogenous metals（Cu and Zn）. The amount of exogenous metal ions（Cu and Zn） added 0.25,0.5,1.0,1.5,2.0,2.5 times separately of environment entalquality standard for soils（GB 15818—1995）. The desorption of contaminated soil samples using simulated rain and acid rain were studied. The critical loads of four kinds of soils under different conditions were calculated based on the standard critical loads of copper and zinc in the class Ⅲ surface water. The critical values of heavy metal ions pollution should be adjust for appropriate numbers for different soil parent material. By this way,it would reach the standard of class Ⅲ surface water,and would not be danger in people＇s health and security.The results showed that：under the simulated acid rain,the critical loads of four kinds of soils based on the class Ⅲ surface water standard were 10 002 mg·kg^-1 Cu,848.1 mg·kg^-1 Zn for SEBC-06：1 162 mg·kg^-1 Cu,612.9 mg·kg^-1 Zn for SEBC-19,9 796 mg·kg^-1 Cu,1 047 mg·kg^-1 Zn for SEBC-20,and 720 mg·kg^-1 Cu,180.2 mg·kg^-1 Zn for SEBC-25.