Supported by the National Natural Science Foundation of China (Nos. 41130526 and 41471174)
【Objective】Hunan Province in Central South China, is a well known nonferrous metal mining base in China. The activities of mining and smelting, however, pose great threat to the cultivated land in the province. This study is to investigate the influences of mining and smelting on heavy metal pollution of soils and rice plants, and to assess its potential risks on human health. 【Method】An investigation was carried out in a town in the northern part of Hunan Province rich in mineral resources, and found that a pyrite smelting factory located at Y Town discharged wastewater, severely polluting a creek and the paddy fields around. Contents of Mn, Cu, Zn, Co, Ni, Cr, Cd and Pb in the soil-rice system of the paddy field on the two sides of the polluted creek nearby the pyrite mine at the town were monitored. 【Result】 Results show that the soils were heavily polluted by Cd, with an over-standard rate being 100%, and by Cu, Zn, Co and Ni, too, with an over-standard rate being 86.7%, 60%, 80% and 60%, respectively. The single-factor pollution index of Cd in the soils reached 12.85, indicating a heavy pollution level, and that of Cu, Zn, Co and Ni was 1.54, 1.26, 1.15 and 1.13, respectively, indicating a light pollution level. The comprehensive pollution index of the eight heavy metal elements in the soils was 9.39, also indicating that the soils as a whole, were heavily polluted. Analysis of heavy metals bio-accumulation factors indicates that Cd and Mn in the soils were easily taken up by rice roots, especially, Cd, of which the availability to rice was much higher than that of all the others, with bio-accumulating factor being 11.84 on average, but Cu, Pb, Co, Cr, Zn and Ni were relatively hard. Pb, Co, Cu, Cd and Cr was mainly accumulated in rice roots, making up 82.5%, 70.6%, 64.8%, 59.4% and 57.5%, respectively, of the total in the plant. Mn, Zn and Ni, however, was rapidly translocated to the shoots of rice plants after being taken up by roots, with only 16.3%, 29.9% and 49.9%, respectively, left in the roots. The brown rice produced in the studied paddy fields was commonly heavily polluted by Cd. The brown rice produced in the fields was found with Cd exceeding the allowable limit (0.2 mg kg-1) by 100%, and about 53.5% of the brown rice was called “Cadium rice” with Cd concentration over 1 mg kg-1. In addition, the brown rice also contained Cu and Ni exceeding the allowable limits by 40% and 86.7%, respectively. The per capita daily ingestion (PDI) of Cu, Zn, Ni, Cr, Cd and Pb through consumption of the rice grain reached 2 732, 7 085, 464, 85, 410 and 37 μg, respectively. The PDI of Cu, Zn, Ni, Cr and Pb was lower than their respective safe levels, but that of Cd reached 5.9 times the safe level set by FAO/WHO.【Conclusion】All the findings in this study demonstrate that the rice produced in the studied area has posed a serious health risk to the local residents.
蒋逸骏,胡雪峰,舒 颖,蒋 颖,滕 青.湘北某镇农田土壤―水稻系统重金属累积和稻米食用安全研究[J].土壤学报,2017,54(2):410-420. DOI:10.11766/trxb201603300061 JIANG Yijun, HU Xuefeng, SHU Ying, JIANG Ying, TENG Qing. Accumulation of Heavy Metals in the Soil-Rice System and Assessment of Dietary Safety of the Rice Produced in the Paddy Fields -- A Case Study of a Town in the Northern Part of Hunan Province, China[J]. Acta Pedologica Sinica,2017,54(2):410-420.复制