Shang Er-Ping, Xu Er-Qi, Zhang Hong-Qi, Huang Cai-Hong
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2018 Oct 8;39(10):4670-4683. doi: 10.13227/j.hjkx.201802139.
Heavy metal pollution of farmland soils in China has been identified as a threat to ecosystem safety and human health. A total of 3006 soil samples were analyzed from arable lands in five grain producing regions of China, which included data from published studies from 2000 up to now. An additional 656 historical samples were derived from the 1980s by a digitizing grained point sites map (Cd, Pb, As, Ni, Cu, Zn, Cr, and Hg) from the PRC Atlas of Soil Environmental Background Values. A GIS-based approach and single factor index method were employed to identify the current status and spatial distribution of heavy metal (Cd, Pb, As, Ni, Cu, Zn, Cr, and Hg) contamination in agricultural soils, and these were then compared with historical data to explore contamination trends over time. Then, based on the I method and the effects of the surrounding environment on contamination rates, pollution sources were analyzed. Results showed that 21.49% of the agricultural soil samples exceeded the environmental quality standard set by the Ministry of Environmental Protection. The proportions of slight, moderate, and severe pollution were 13.97%, 2.50%, and 5.02%, respectively. Pollution is more extensive in the south compared with the north. Exceedance percentages in the Sichuan Basin (SC), Yangtze River Middle Plain and Jianghuai Plain (CJ), Huang-Huai-Hai Plain (HHH), Songnen Plain (SN), and Sanjiang Plain (SJ), were 43.55%, 30.64%, 12.22%, 9.35%, and 1.67%, respectively. The main pollutants were Cd, Ni, Cu, Zn, and Hg, with exceedance percentages of 17.39%, 8.41%, 4.04%, 2.84%, and 2.56%, respectively. Since the 1980s, heavy metal pollution has increased by 14.91%. The proportion of Cd, Ni, Cu, Zn, and Hg increased by 16.07%, 4.56%, 3.68%, 2.24%, and 1.96%, respectively. Except for SJ, exceedance percentages in cultivated land increased significantly, while the exceedance percentages of Cd, Ni, and Cu in the southern areas were higher than for the northern areas-although the growth rate of Hg and Cr in the south was lower than that in the north. The main sources of Cd and Hg were anthropogenic pollution, while the other six heavy metals were from predominantly natural sources. However, about 20.00% of Pb, Zn, and Cu were affected by anthropogenic activities. Mining, industry, and sewage water were the main sources of pollution. In addition to the larger impact of sewage irrigation in the north, other sources of pollution showed greater influence in the south. Mining mainly caused pollution by Cd, Hg, Ni, Cr, and Cu, while excessive levels of Cd, Ni, Cu, Zn, and Hg was the signature of industrial pollution. Irrigation with sewage effluent causes excessive Cd, Ni, and Zn. Results from this study provide valuable information for agricultural soil management and food safety in China.
中国农田土壤的重金属污染已被确认为对生态系统安全和人类健康的一种威胁。共对中国五个粮食产区的耕地土壤进行了3006个样本分析，其中包括2000年至今已发表研究的数据。另外656个历史样本来自20世纪80年代，通过对《中华人民共和国土壤环境背景值图集》中的数字化点位地图（镉、铅、砷、镍、铜、锌、铬和汞）进行处理获得。采用基于地理信息系统（GIS）的方法和单因子指数法来确定农业土壤中重金属（镉、铅、砷、镍、铜、锌、铬和汞）污染的现状和空间分布，然后将其与历史数据进行比较，以探究污染随时间的变化趋势。接着，基于内梅罗（I）方法以及周边环境对污染率的影响，对污染源进行了分析。结果表明，21.49%的农业土壤样本超过了环境保护部设定的环境质量标准。轻度、中度和重度污染的比例分别为13.97%、2.50%和5.02%。与北方相比，南方的污染更为广泛。四川盆地（SC）、长江中下游平原和江淮平原（CJ）、黄淮海平原（HHH）、松嫩平原（SN）和三江平原（SJ）的超标率分别为43.55%、30.64%、12.22%、9.35%和1.67%。主要污染物为镉、镍、铜、锌和汞，超标率分别为17.39%、8.41%、4.04%、2.84%和2.56%。自20世纪80年代以来，重金属污染增加了14.91%。镉、镍、铜、锌和汞的比例分别增加了16.07%、4.56%、3.68%、2.24%和1.96%。除三江平原外，耕地的超标率显著增加，且南方地区镉、镍和铜的超标率高于北方地区，尽管南方汞和铬的增长率低于北方。镉和汞的主要来源是人为污染，而其他六种重金属主要来自自然源。然而，约20.00%的铅、锌和铜受到人为活动的影响。采矿、工业和污水是主要污染源。除北方污水灌溉影响较大外，其他污染源在南方的影响更大。采矿主要导致镉、汞、镍、铬和铜污染，而工业污染的特征是镉、镍、铜、锌和汞超标。污水灌溉导致镉、镍和锌超标。本研究结果为中国农业土壤管理和食品安全提供了有价值的信息。
