China's overall land environmental quality remains good
Recently, the China Geological Survey released the "China Cultivated Land Geochemical Survey Report (2015)." The report shows that the environmental quality of the land within the survey area is generally good. Of the 1.386 billion mu of cultivated land surveyed (accounting for 68% of the country's total cultivated land area), more than 1.272 billion mu of cultivated land is free of heavy metal pollution, accounting for 91.8% of the total cultivated land area surveyed this time.
The report shows that as of 2014, China had completed a total land geochemical survey area of 1.507 million sq km, including 1.386 billion mu of cultivated land surveyed. The 1.272 billion mu of pollution-free cultivated land is mainly distributed in the Jiangsu-Zhejiang-Shanghai area, the Northeast area, the Beijing-Tianjin-Hebei-Shandong area, the Northwest area, the Shanxi-Henan area and the Qinghai-Tibet area, among others. In the Beijing-Tianjin-Hebei-Shandong area and the Shanxi-Henan area, pollution-free cultivated land accounts for more than 99% of all cultivated land surveyed in those regions. In addition, this survey newly discovered 52.44 million mu of green selenium-rich cultivated land resources, mainly distributed in the Fujian-Guangdong-Hainan area, the Southwest area, the Hunan-Hubei-Anhui-Jiangxi area, the Jiangsu-Zhejiang-Shanghai area, the Shanxi-Henan area and the Northwest area, among others.
The survey results also show that within the areas where the survey has been completed, there are 34.88 million mu of cultivated land with moderate—severe heavy metal pollution or exceeding standards, and 78.99 million mu of cultivated land with slight—mild pollution or exceeding standards. High geological background, secondary enrichment during soil-forming processes and human activities are the main causes of cultivated land pollution or exceedance of standards.
The report recommends that the fundamental role of geological survey results in land resource management, modern agricultural development and ecological environment improvement should be fully brought into play. For currently pollution-free cultivated land, the possible pollution impact of industrial and agricultural production activities on cultivated land should be actively prevented and controlled. Selenium-rich cultivated land should be strictly protected and scientifically used, and dynamic monitoring and management of quantity and quality should be strengthened. For cultivated land with moderate—severe heavy metal pollution or exceeding standards, it is recommended that remediation and treatment be carried out according to different circumstances, that planting structure or land use be adjusted, and that cause analysis and ecological risk assessment be conducted. Regarding changes in soil organic matter and pH, active measures should be taken to reduce the extraction and use of groundwater for cultivated land in the north, intensify surveys and remediation of soil erosion, and control industrial and agricultural production activities that may form pollution sources and reduce the impact of human activities.