Research of the Evaluation on Heavy-Metal Pollution in Rice by Sewage Irrigation

This paper took the SongSan wastewater irrigation district of Liaoning Province, Anshan city as object of study. Base on the survey on the sewage irrigation situation, heavy metal concentration in rice grain and drinking water were measured through single pollution index evaluation and comprehensive pollution index evaluation (Nemerow index method). It could be served as the basis for environmental management and relevant laws and regulations. Experimental results showed that drinking water were not polluted by heavy mental. Sewage irrigation had a comparatively small impact on drinking water. According to the heavy mental determination results of grain crop seeds, it can conclude that the Cu and Pb content were above the national food quality standard. The pollution is serious, however, the content of Zn and Cd were below or close to the national food quality standard, which is in danger of exceeding the standard. Determined by comprehensive pollution index, it showed that the rice in the whole sewage irrigation is serious polluted by heavy mental. The heavy metal pollution presented the characteristics of extensive area-source pollution. Pollution intensity was strengthened and more difficult to be managed.