IMPACT OF COAL SURFACE MINING AND RECLAMATION ON SURFACE WATER CHEMICAL CONCENTRATIONS AND LOAD RATES IN THREE OHIO WATERSHEDS1

ABSTRACT: Information is lacking on the watershed scale effects of mining and reclaiming originally undisturbed watersheds for coal on surface water chemical concentrations and load rates for a variety of constituents. These effects were evaluated on three small, geologically dissimilar watersheds subjected to surface mining in Ohio. Comparisons were made between phases of land disturbances using ratios of average concentrations and load rates: Phase 1 (natural), subphases of Phase 2 (mining and reclamation), and subphases of Phase 3 (partial reclamation and final condition) using 4,485 laboratory analyses of 34 constituents. Average concentration and load rate ratios were categorized into three classes—minor, moderate, and substantial. Mining and reclamation (M/R) affected flow duration curves in different ways‐baseflow changes were variable, but high flows generally increased. The average concentration ratios for all sites were classified as 15 percent “minor,” 36 percent “moderate,” and 49 percent “substantial” (average ratio of 2.4.) Generally load rate ratios increased due to mining and reclamation activities (average ratio of 3.3). Minor, moderate, and substantial impacts were found on average for 7 percent, 23 percent, and 70 percent, respectively, of load rate ratios. The impact of M/R on average load rates was not necessarily the same as on average concentrations due to changed hydrology and can be opposite in effect. The evaluation of the impacts of M/R requires knowledge of changing hydrologic conditions and changing supplies and rates of release of chemicals into streams. Median sediment concentration ratio is an indicator of average constituent load rate ratio of a wide variety of chemical constituents and is useful for development of best management practices to reduce chemical loads. The site at which diversion ditches were not removed during final reclamation sustained large chemical load rates, and removal of diversions at the other mined site reduced load rates. Revegetation of poorly reclaimed areas decreased chemical load rates. Chemical load rates were sensitive to geology, mining, and reclamation methods, diversions, and changing hydrology, concentration flow rate regressions, and watershed areas.     

建筑物下采煤技术的研究现状与发展趋势

我国建筑物下采煤的研究从20世纪60年代开始,先后在本溪、鹤壁、抚顺、枣庄、峰峰、蛟河等矿区进行试验,取得了成功的经验和宝贵的监测资料。在综合分析大量文献的基础上,从协调开采法、充填开采方法、条带开采、覆岩离层注浆等多种开采技术对建筑物下开采方法进行了研究和论述;展望了我国建筑物下开采的发展趋势,认为覆岩离层注浆、矸石充填、条带开采、原地重建抗变形房将是我国建筑物下采煤技术的发展方向。     

Prairie strips reduce fecal indicator bacteria concentrations in simulated runoff

Vegetative filter strips (VFS) have shown promising results in reducing the downstream transport of many agroecosystem contaminants. A recently developed type of VFS, prairie strips, has been shown to significantly reduce the impact of corn and soybean production systems on water quality in terms of sediment, nitrogen, and phosphorus losses. This study assessed potential additional benefits of prairie strips to include the reduction of pathogens. To assess the impact of prairie strips on manure-laden agricultural runoff, we utilized a physical model of prairie strips in a laboratory flume to conduct highly controlled overland flow experiments. Escherichia coli and Enterococcus concentration reductions of up to 45% and 65% were observed for runoff and infiltration flows, respectively, while mass load reductions of up to 65% were observed for surficial runoff flows. The degree of concentration or mass load reductions was dependent on the residence time of the flow within the strip and the partitioning of overland flow running onto the strip to infiltration and runoff flows. Based on our results and a review of the literature, we developed a design method to provide guidance on the width of prairie strip buffer needed to achieve a user-defined reduction of fecal bacteria concentration.     

粪大肠菌群快速测定——纸片法的应用

采集苏州具有代表性的地表水水体22个点位的样品,进行粪大肠菌群的测定方法比较,结果表明,《粪大肠菌群快速测定--纸片法》适于测定受粪便污染程度较轻的湖泊水体.但是,该方法的培养时间对阳性管率有明显影响,认为16 h～18 h是比较理想的培养时间.     

Nutrient transport within three vegetative treatment areas receiving silage bunker runoff

Silage bunker runoff can be a very polluting substance and is increasingly being treated by vegetative treatment areas (VTAs), but little information exists regarding nutrient removal performance of systems receiving this wastewater. Nutrient transport through the shallow subsurface of three VTAs (i.e. one VTA at Farm WNY and two VTAs at Farm CNY) in glaciated soils containing a restrictive layer (i.e., fragipan) was assessed using a mass balance approach. At Farm WNY, the mass removal of ammonium was 63%, nitrate was 0%, and soluble reactive phosphorus (SRP) was 39%. At Farm CNY, the mass removal of ammonium was 79% in the West VTA, but nitrate and SRP increased by 200% and 533%, respectively. Mass removal of ammonium was 67% in the East VTA at Farm CNY; nitrate removal was 86% and SRP removal was 88%. The East VTA received a much higher nutrient loading, which was attributed to a malfunctioning low-flow collection apparatus within the settling basin. Results demonstrate that nutrient reduction mechanisms other than vegetative uptake can be significant within VTAs. Even though increases in nitrate mass were observed, concentrations in 1.65m deep wells indicated that groundwater impairment from leaching of nitrate was not likely. These results offer one of the first evaluations of VTAs treating silage bunker runoff, and highlight the importance of capturing concentrated low flows in VTA systems.     

福建省饮用水源地植被缓冲带建设规划研究

饮用水水源地是水环境的重要组成部分,是水环境功能区划中具有最高使用功能的水域。本研究通过对福建省饮用水源地保护区周边不同类型植被缓冲带的生态调查的基础上,对植被缓冲带的结构和布局、缓冲带宽度要求以及缓冲带植被选择和配置等要素方面进行设计,提出三种不同类型饮用水源地的植被缓冲带规划建设。本研究对于保护水源地水质,保障饮水安全和人民身体健康,促进资源的可持续利用和生态、环境的可持续保护有着重要的作用。     

油罐车导静电拖地带防静电效果研究

通过对油罐车对地泄放电阻值的检测,并对比导静电拖地带接地前后油罐车对地泄放的电阻值,研究不同情况下导静电拖地带对油罐车静电泄放的效果,探讨导静电带作为静电泄放途径存在的必要性。     

基于五林矿场的冻融环境下缓倾斜边坡稳定性分析研究

五林露天矿场处于高寒冻融环境,地质条件复杂.文章通过冻融机理及边坡稳定性理论研究,利用直剪试验获得力学参数,结合数值模拟,从冻结厚度、融化厚度、含水率、冻融循环次数四个方面对目标矿区边坡稳定性进行分析.分析发现该矿区边坡稳定性较好,坡体滑塌风险较小,实验发现含水量和循环次数对边坡稳定性影响较大,三次冻融循环以后,含水量为主要影响因素.在此基础上提出铺设排水管道,使用土工格栅防护,雷达监测等相关防护措施.     

PA66GF25尼龙隔热条材料热氧老化性的研究

向PA66GF25尼龙隔热条材料中分别加入三种抗氧剂体系,通过测定样品热氧老化实验后的拉伸强度值,研究不同抗氧剂体系对PA66GF25尼龙隔热条材料耐老化性能的稳定作用。结果表明,三种抗氧体系均提高了材料的耐老化性能,尤其是含有碳自由基捕获剂的三元复配体系。同时,对尼龙隔热条材料的静态使用寿命进行了分析与预测:不含抗氧剂的材料静态使用寿命仅为4.34 a,含三元复配抗氧体系的材料则可高达57.05 a。     

Effects of Buffer-Strip Retention and Clearcutting on Land Snails in Boreal Riparian Forests

Abstract:  We investigated the short-term effects of forest clearcutting on land snails (terrestrial gastropods) in 15 forest stands along small streams in Sweden. Two different silvicultural treatments were applied at each site: clearcutting across the stream channel and buffer strips 10 m wide on each side of the stream. Additionally, we studied 10 reference sites in unlogged riparian forests along similar-sized streams. All sites were studied before logging and then 2.5 years after logging. After clearcutting the number of individuals in a 0.5-m² sample from each site decreased on average from 107 to 87, and the mean number of species per sample decreased from 9.9 to 7.7. Most species were negatively affected, but there were also clear differences in sensitivity. There were correlations between species survival and ground moisture. At the wettest clearcut sites with an almost intact bryophyte cover, the land snails were unaffected by clearcutting. This result suggests that wet or moist forest floors can serve as refugia even at very small spatial scales (e.g., shallow hollows, crevices). If this is an important mechanism, the spatial distribution of small habitats could be important for the long-term survival of the snail fauna or other small, dispersal-limited organisms at clearcut sites. In the buffer strips, the number of individuals decreased but not the number of species, indicating that buffer-strip retention is a good practice for protecting land snails in riparian forests. The varying effectiveness of the buffer strip could partly be explained by the proportion of the remaining basal area, emphasizing that buffer strips could be even more effective if efforts are made to avoid heavy damage by windthrows.