高潜水位煤矿区生态风险识别与评价

生态风险评价是生态环境保护与管理的重要研究内容,并广泛运用于流域与较大范围的区域尺度的研究。以区域生态风险评价理论为基础,结合高潜水位煤矿区生态环境以及煤炭开采对生态系统造成的危害的特点,通过分析风险源、风险受体、生态终点以及暴露—响应过程,对高潜水位煤矿区生态风险的识别与评价方法进行了研究,构建了典型高潜水位煤矿区的生态风险识别与评价概念模型与空间分析框架,分析了煤矿区生态风险识别的主要技术手段与方法,并构建了以缓冲为主要手段的综合生态风险评价方法。选择山东东滩煤矿作为研究对象,针对研究区内存在的采煤塌陷、洪涝、污染、景观及社会等生态风险类型,定量评价其空间差异,并提出相应的风险防范措施。案例分析结果表明,研究区综合生态风险重度、中度、一般、轻度分别占到研究区的4.70%,64.00%,24.09%,7.20%。生态风险较高的区域主要位于矿区中西部,为煤矸石山、裸露煤炭堆积与发电厂分布区域;中度风险是研究区主要的风险类型。从降低生态风险保障矿区生态安全角度,在未来矿区规划与生态治理过程中,提出了具体的应对措施,包括:(1)注重源头控制;(2)建立高生态风险区域阻隔带;(3)加强污染的监测与控制;(4)采用边开采边治理技术。建议加强生态风险高区域的阻隔,建立生态缓冲带,减缓对整个矿区的综合影响,构建东滩煤矿生态风险防范的空间结构。

Ecological risk identification and assessment for a coal mine with a high groundwater table

Ecological risk assessment is one of the most important subdivisions in eco-environmental protection and management, and it is widely used to evaluate ecological risks on both watershed and regional scales. In this study, we conducted identification and ecological assessment by analyzing risk sources, bearer, ecological endpoints, and the exposure-response process on the basis of regional ecological risk assessment coupled with the unique characteristics of mining ecosystems in high groundwater table areas. The identification and evaluation method for ecological risk was studied, and an ecological assessment conceptual model and spatial analysis framework for a coal mine with high ground water were proposed. Furthermore, a comprehensive ecological risk assessment method was proposed on the basis of the spatial buffering theory. The proposed model identifies and assesses mining-induced ecological risks. The Dongtan coal mine in Shandong Province was selected to test this model and framework. The major ecological risks in this mine include land subsidence, floods, water pollution, landscape, and social issues. The degrees of single and comprehensive ecological risk were evaluated. On the basis of the analysis, ecological risk was quantitatively analyzed and spatial strategies for ecological planning in the coal mine were broached. Severe, moderate, general, and mild comprehensive ecological risks were 4.7%, 64%, 24.09%, and 7.2%, respectively. The high ecological risk was located mid-west of the coal mine with sites for coal waste piles, exposed coal, and power plants. Despite the small area occupied, enough attention should be paid to high ecological-risk areas because of their high potential of air, water, and soil pollution. The moderate ecological risk was the dominant risk-type and was present in 64% of the whole region, where most of the mining subsidence is distributed. Mining subsidence triggers flood, farmland loss, and related social issues. The general and low ecological risks were located in the mining industry square area and coal mine edges (where coal pillars protect the ground infrastructure), and were kept at a distance from pollution sources. On the basis of quantitative and spatial ecological risk assessment, specific recommendations were proposed after considering reduced ecological risk and protection from an ecological security perspective for the mine. The countermeasures and suggestions include:(1) Source control. Coal waste piles, exposed coal, and power plants are the main causes of pollution and are considered as point-source pollution; therefore, we recommend that the coal company should focus on source control, improve the comprehensive utilization of coal waste, eliminate exposed coal, and implement monitoring of water and air emissions in power plants. (2) Establishment of barriers for high ecological-risk areas. High ecological-risk areas were established over a long period and cannot be eliminated immediately; therefore, establishment of ecological buffer zones and barriers for mitigating the effects of high ecological risks is strongly recommended. Specific measures include shelterbelt construction and utilization of geotextiles. (3) Improved monitoring and pollution control. Field sampling was not conducted in this study; the coal company should build a monitoring system to assess high pollution levels and spatial distribution of ecological risk areas and consider the dominant wind direction. (4) Concurrent mining and reclamation, filling materials in high groundwater and plain coal mines, and concurrent mining and reclamation technology are recommended to protect the topsoil and improve land reclamation efficiency.