STATISTICAL CHARACTERISTICS OF COAL-MINE DISCHARGES ON WESTERN PENNSYLVANIA REMINING SITES1

ABSTRACT: Under an approved remining program, a coal mine operator can remine abandoned sites without legally assuming treatment responsibilities of the previously degraded water, as long as these discharging waters are not further degraded. Determination of discharge degradation caused by remining of abandoned coal mines requires knowledge of mine water quality and discharge flow rate characteristics both before and after remining. Normality tests performed on the water quality and flow data from 57 mine discharges indicate generally nonnormal distributions and extreme right-skewness. Exploratory data analysis (notched box-and-whisker plots) of the differences among medians indicates that the water quality of underground mines was more highly degraded in terms of acidity, iron, and sulfate concentrations than that from surface mines. Spearman's rank correlation tests, normality testing, and exploratory data analysis indicate that discharge flow rate is the primary controlling factor on the variability of pollution load rate. Reduction of recharge from the surface and adjacent unmined strata should decrease the mine discharge flow rate and in turn the pollution load.     

挖掘荷载冲击下输气管道动力响应分析

为了对挖掘荷载冲击下输气管道的动力响应情况与影响因素进行分析,利用ANSYS AUTODYN有限元软件对挖掘荷载冲击管道的过程进行数值模拟,根据仿真结果分析不同挖掘环境下管道的受损程度。研究结果表明:当受到挖掘荷载的作用时,管道的应力分布成对称状,在荷载作用位置单元处,有效应力达到最大值,且挖掘荷载大小与斗齿数对管道受损程度的影响较为明显。     

区域点源和非点源磷入河量计算的二元统计模型

基于流域或区域点源和非点源磷入河过程的水文学差异,以及影响河流持留作用的主要机制,建立了描述河流段末磷负荷量与流量和水温之间定量关系的二元统计模型;通过逐月的河流水文水质监测数据对模型中4个系数的有效校正和验证,实现了对点源和非点源磷入河过程的准确定量.与现行的水文估算法相比,该模型既考虑了河流磷的持留能力及其时间变异性,也考虑了上游水体输入的磷负荷量,推进了对磷污染过程的定量认识,满足了我国以行政区为主要水污染控制管理单元的现实需要.应用该模型,计算了浙江长乐江集水区2004～2009年的总磷(TP)入河量.结果表明,TP年入河总量为(54.6±11.9)t.a-1,其上游水体输入、点源和非点源的入河量贡献率分别为5%±1%、12%±3%和83%±3%.夏季5～6月和8～9月的非点源TP累计入河量占其全年的50%±9%,增加了引起下游水体藻类暴发的风险.河流TP持留量为(4.5±0.1)t.a-1,占年入河总量的9%±2%;5～9月的TP累计持留量占全年的55%±2%,表明河流持留能力对流域或区域磷素迁移转化过程的调控作用不容忽视.本研究建立的二元统计模型仅需常规的河流水文水质监测数据,无需专业软件知识,且计算结果直接来源于实际的河流水文水质测算值,为实施流域或区域磷污染总量控制策略提供了一种简便、实用、可靠的定量工具.     

Fish Communities of Small Ponds in the Udmurt Republic: Structural Features and Trends in Anthropogenic Successions

The ichthyofauna of 20 small ponds in the Udmurt Republic was studied to estimate the dependence of fish species abundance on pond size and anthropogenic load, as well as trends in the succession of dominant species complexes in ponds exposed to the prevailing impact of agricultural activity. Changes in the ecological structure of fish communities in small ponds upon an increase in the anthropogenic load were analyzed. Some specific features of the species composition of ichthyofauna in technogenic pond biocenoses were revealed.     

洱海入湖河流白鹤溪主要排污口及其污染负荷解析

对洱海西部入湖河流白鹤溪主要排污口进行调查,采用等标污染负荷法对各个排污口排污情况进行分析。结果表明:白鹤溪在丰水期与枯水期等标污染负荷相当,南支的等标污染负荷大于北支,最主要的污染因子为总氮和总磷。白鹤溪最主要的排污口为南3排污口,其次为北2排污口,总氮总磷是其主要污染因子,高锰酸盐指数在北2排污口也占有较大比例。各个排污口的污染因子在丰水期与枯水期差异较大。以排污口形式进入白鹤溪的污染负荷是白鹤溪污染负荷的主要来源。     

铀尾矿库地下水污染风险评价方法研究

针对尾矿库中铀对地下水的污染风险,通过选取污染物废液产生量、污染毒性、污染物迁移性和场地运行时间4个污染源特征指标建立污染源荷载风险评价体系,并采用层次分析法确定权重,再结合地下水的固有脆弱性评价,用两者风险等级相叠加的方法划分出5种地下水污染风险等级。同时,以某铀尾矿区为例进行地下水污染风险评价,结果表明该地区地下水污染风险级别为中低风险等级。     

不同岩性试片溶蚀速率差异及意义

评价岩性对溶蚀速率的影响有助于提高岩溶碳汇强度估算精度,对当前全球气候变化研究意义重大。本文通过在山西晋中盆地西南,吕梁山东侧的半干旱岩溶区典型小流域开展标准试片与当地试片的对比溶蚀试验研究,结果显示当地试片的溶蚀速率(0.122 3~0.532 8mg/(cm2·a)和岩溶碳汇强度(1.713tCO2/(km2·a))明显小于标准试片(0.254 7~0.551 1mg/(cm2·a)和1.821tCO2/(km2·a)),表明使用标准溶蚀试片法会使岩溶碳汇强度被高估。当地试片的溶蚀速率与酸不溶物含量呈负相关关系,进一步表明当地试片酸不溶物含量(2.58%~10.86%)大于标准试片(3%)是造成其溶蚀速率和岩溶碳汇强度小于标准试片的重要原因。也就是说,由于埋放地地层岩性与标准溶蚀试片岩性特征存在差异,不同地区均采用埋放标准试片的溶蚀实验方法来研究岩溶碳汇效应会产生较大的误差。因此,为了更加精确的计算岩溶碳汇量,后期研究中有必要使用埋放地的岩性试片来替代标准溶蚀试片。     

Impact of hydraulic loading on removal of polycyclic aromatic hydrocarbons (PAHs) from vertical-flow wetland

The effects of polycyclic aromatic hydrocarbons (PAHs) removal on lab-simulated vertical wetland systems, each containing eight dominant species, under continuous- and intermittent-flow feeding modes, were determined. The main results were: (1) PAHs removal effect was greater in intermittent-flow system than in continuous-flow system, with the exception of the floating plant Hydrilla verticillata wetland. This may be due to pollutants remaining stable for longer duration under intermittent-flow mode, which is conducive to microbial, plant, and water absorption of PAHs, as well as to microbial decomposition and absorption by plant roots; (2) absorption and degradation rates of PAHs varied among wetland body plants in different periods with removal efficiencies of 30%–70% observed following the first and fifth cycles, and under high-performance degradation conditions; (3) mean removal rates of PAHs by hydrophytes under continuous-flow mode were as follows: H. verticillata (34.4%), Arundo donax (Gramineae) (33.2%), Phragmites australis (28.7%), Ipomoea aquatica Forsk (Convolvulaceae) (28.5%), Zizania aquatic (27.6%), Calla palustris (Araceae) (27.2%), Acorus calamus (26.8%), and Hardy canna (17.9%); (4) average rates of PAHs removal by hydrophyte under intermittent-flow mode were as follows: A. donax (40.5%), Z. aquatic (37.9%), A. calamus (37.0%), P. australis (36.9%), Hardy canna (34.6%), C. palustris (33.9%), I. aquatica (31.2%), and H. verticillata (29.3%).     

The deployment of γ-irradiation for reducing polycyclic aromatic hydrocarbons and microbial load in wheat kernels

Food contamination may contribute to serious human health problems. In this work, the effect of γ-irradiation 0, 5, 10, and 15 kGy doses on the removal of polycyclic aromatic hydrocarbons from wheat kernels was investigated. Additionally, variations in the contents of 16 congeners on bacterial load and other chemical parameters were studied. Polycyclic aromatic hydrocarbons concentrations were determined by high-performance liquid chromatography followed by fluorescence detection. The effects of γ-irradiation on the concentrations varied for each congener, with the highest irradiation dose being the most effective. Benzo[a]pyrene was reduced by ～50%, and the total concentration of all congeners decreased dramatically from 154 to 21 µg.kg^?1 upon 15 kGy irradiation at a dose rate of 8.49 kGy h^?1. The total bacterial load was reduced from 2.4 to < 1 log₁₀ cfu g^?1, while wheat chemical properties were not affected.     

中空玻璃受热破裂行为规律研究

研究了单层玻璃厚度为6mm,两块玻璃间距为6mm的中空玻璃的受热响应规律,分析了向火面和背火面玻璃板的表面温度、玻璃板向火面中心点处的热通量、两块玻璃的破裂时间、裂纹形态以及玻璃脱落情况等。定义玻璃边长区域范围为[-0.5L,0.5L],则玻璃首次起裂点均位于被遮蔽边上,且在[-0.25L,0.25L]的范围内。进一步研究了遮蔽方式对中空玻璃破裂行为的影响,在本实验条件下,四边遮蔽的向火面玻璃最易破裂,且左右垂直遮蔽比上下水平遮蔽情况下脱落程度严重。