扬中地区农田土壤重金属污染调查与评价

对扬中地区主要农田土壤进行了采样监测,按照国家无公害农产品产地的环境质量标准,采用单项污染指数法和尼梅罗综合指数法对土壤的8个重金属污染指标进行了环境质量评价。结果表明,扬中农田土壤均受到重金属轻污染,其中Cd、Hg污染主要与化肥、农药等大量施用有关;As、Pb、Cu、Zn污染可能与工厂废气及汽车尾气排放有关;而Cr、Ni污染主要与长江石灰性冲积母质特征有关。结合1990年的土壤数据,计算了重金属的累积速率,反映近年来重金属的不断输入。污染区的农产品生态效应研究表明,重金属污染已经威胁到农产品安全。

Survey and Assessment of Heavy Metal Pollution of Cropland Soil in Yangzhong Area Jiangsu Province

Soil and crop samples were collected from the major cropland in Yangzhong Area of Jiangsu Province for assessment of soil environmental quality with the single pollutant index method and the Nemerow comprehensive index method, according to the national standards for environmental quality of farmland producing hazard-free agricultural products and the soil indices for eight heavy metal pollutants. Results indicated that the soils were slightly polluted. Of the eight heavy metals, Cd and Hg pollution in the soil may be related to high-rated application of chemical fertilizer and pesticide; As, Pb, Cu and Zn pollution to exhaust gases from factories and automobiles; while Cr and Ni pollution mainly to the calcareous parent material in the Changjiang River valley. With the data in 1990 as basis, calculation was conducted for accumulation rates of these heavy metals, reflecting continuous heavy metal input. The study on eco-effect of heavy metals on agricultural products in the polluted region revealed that heavy metal pollution has turned out to be a threat to safety of the agricultural products.