客观地看待我国耕地土壤环境质量的现状

——关于《全国土壤污染状况调查公报》中有关问题的讨论和建议

王玉军，刘 存，周东美，陈怀满

（中国科学院南京土壤研究所 土壤环境与污染修复重点实验室，南京 210008）

摘 要：《全国土壤污染状况调查公报》是调查样点真实而表观的反映。之所以说它是真实的，因为它是从大约630万km²实际调查面积中所取土壤样品分析结果所获得的结论；继之说它是表观的，因为它对于数据形成的原因缺乏必要的深度分析，因而对土壤环境质量现状的描述需要客观而理性的对待。文章第一部分就有关标准、耕地超标判别的关键因素、高背景值土壤样点问题、污染或超标点位的溯源性分析等进行了讨论，提出了下列见解：（1）需要明确评价标准。就耕地土壤重金属而言，其标准受到多种因素的影响，故当在公报中表明质量状况时，应该说明评估的标准，它应该与土壤和农作物类型密切相关。（2）需要给出对应土壤样点农产品中有关元素的含量。农产品可食部分重金属含量是判断土壤重金属影响的关键指标，缺乏相关数据则无法判断土壤是否污染。（3）高背景值土壤不应列为污染土壤。根据土壤污染的定义，它不具有污染的特征要素。在一些地区因母质和自然成土过程所形成的高背景值，通常归属于环境异常；在利用方面应属于“土宜学”范畴。（4）污染或超标点位的原因应该慎重甄别。从物料平衡的角度考虑，区域性Cd增量要达到50%或者40%的可能性需要进一步考虑。文章的第二部分讨论了采用负载容量管理法对土壤环境质量管控的优势和可行性。从正常土壤考虑，有利于从单一标准过渡到双标准管理，从而兼顾土壤自然环境质量的可持续性和土壤资源的可持续利用；从污染土壤考虑，有利于修复标准的确定；从污染源影响的赔偿考虑，根据外源物质所消耗的容量值，可量化有偿利用和恢复容量的经济评估；从责任主体考虑，有利于责任主体的认定和保护措施的落实；从方法的简便性和可操作性考虑，简单易行。

关键词：调查公报；土壤污染；土壤环境质量；重金属；容量管理法
中图分类号：X825文献标志码：A文章编号：1672-2043（2014）08-1465-09 doi:10.11654/jaes.2014.08.001

A Critical View on the Status Quo of the Farmland Soil Environmental Quality in China: Discussion and Suggestion of Relevant Issues onReport on the national general survey of soil contamination

WANG Yu-jun, LIU Cun, ZHOU Dong-mei, CHEN Huai-man

（Key Lab of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China ）

Abstract: The Report on the national general survey of soil contamination was a reflection of the reality and appearance of the survey’s samples and methodologies conducted by the Ministry of Environmental Protection and the Ministry of Land and Resources. Since the soil samples were collected from the de facto survey area about 6.3 million km2, the conclusion drawn from the analytical results of such large sample size was fairly representative of the current status of China忆s soil ; while there was an apparent lack of necessary in-depth analysis of the formation of data. Thus an objective and rational viewpoint on the description of the status quo of the soil environment quality is needed. In the first part of this article, we discussed the standards, the key factor to identify whether the heavy metal levels in farmland exceed the national standards, the problems about soil samples collected from high background areas and the traceability analysis of contaminants where the levels of contaminants exceed the standards. Based on our discussion, the following opinions were put forward:（1） The evaluation standards need to be clarified, as in terms of heavy metals in the cultivated land, the choice of standards is affected by many factors, which is closely related to the type of soil and crops.（2）The corresponding content of heavy metal in agricultural products where the soil samples were collected need to be evaluated, since the heavy metal content in the edible part of the agricultural products is the key indicator to determine the impact of heavy metals in the soil. Lacking the corresponding data, it cannot determine whether the soil is contaminated or not.（3） Soils with high background levels of heavy metals should not be classified as the contaminated soil. According to the definition of soil contamination, such area does not have the characteristic feature of contamination, as the high background values of heavy metals in the area come from the natural parent materials or the soil formation processes. It should be generally attributed to the environmental exceptions, and in the term of soil utilization, it should belong to the category of "science of soil adaptability".（4）The sources of soil pollution where the standards were exceeded should be carefully screened. When the Cd content in soil increased 40% or 50%, the possible Cd input from external sources should be considered from the viewpoint of material balance.

The loading capacity of soil for contaminants was suggested to be adopted as guideline principle in the management of soil environmental quality, and its advantage and feasibility was discussed in the second part of the article. For the consideration of general soil management, it is advantageous to transit from a single standard to composite standards, which takes into account the sustainability of natural soil quality and sustainable utilization of soil resources. Regarding the contaminated soil, the incorporation of the concept of loading capacity will be beneficial for determining the remediation criteria. In the economic assessment of the pollution compensation, the compensated utilization and the restoring capacity could be quantified according to the capacity consumed by exogenous substances. It will also help to assess the liability and implement the protection measures in identifying the legal responsibility subject of soil pollution. The procedure of calculating the loading capacity of soil for contaminants is practical and feasible, and thus it is recommended to be incorporated in the future management of soil environmental quality.

Keywords: report on the national general survey on soil contamination; soil pollution; soil environmental quality; heavy metal; management method by loading capacity

客观地看待我国耕地土壤环境质量.pdf