鞍山市大气尘和金属元素沉降通量及污染特征

通过采集鞍山市11个点位的降尘样品以及土壤样品,用ICP-MS分析了Cu、Mn、Zn、Pb等元素含量,并计算其沉降通量。结果表明,鞍山地区大气降尘的沉降通量为2.92～59.8g/(m2.month),其中鞍钢厂区沉降通量均值为31.6g/(m2.month),分别是周边地区和对照地区的4.72倍和10.5倍。重金属As、Cr、Pb和Cd的沉降通量分别为3.78、45.5、42.8、0.457g/(hm2.month)。降尘中各元素的富集系数为0.29～190,其中Cu、Fe、Zn、Mo、Cd、Pb和Se的富集系数大于10,说明这些元素主要来自于人为源。鞍钢厂区土壤中Cu、Pb、Mn、Zn、Mo、Cd、Ca、Fe和Se的含量较辽宁省土壤背景值高,说明其土壤环境已经受到了人类活动的影响。     

大气颗粒物中铅污染来源解析技术

近年来,我国大气颗粒物中铅的污染比较严重,其来源比较复杂.大气颗粒物中铅污染来源的解析比较成熟的主要有同位素丰度比、无机多元素分析、质子微探针技术等方法,而序列提取、化学形态分析等技术还处于探索阶段.     

南通市某钢丝绳行业集中区降尘中重金属污染状况评价

针对南通市钢丝绳行业集中区重金属污染问题,分析降尘中的铅、镉、铬、铜、镍、铁、锌、锰等重金属含量,并采用污染指数法和地累积指数法对降尘中重金属污染状况进行评价。结果表明,该集中区降尘中重金属污染程度依次为Zn>Pb>Cd>Cu>Fe>Mn>Ni>Cr,铅、锌为主要污染因子,铅、锌污染级别均处于重污染级别。     

图们市大气颗粒物中重金属含量及分布特征

采集了图们市2006年秋、冬两季的TSP和PM10样品,采用湿法消解-原子吸收分光光度法测定了其中的铅、镉、饲、锌、铬、铁、锰7种重金属.结果表明,图们市大气颗粒物中重金属含量由高到低的顺序是Fe>Cr>Zn>Pb>Mn>Cu>Cd.多数重金属元素含量冬季高于秋季,在一天之内早晨的重金属浓度也往往高于晚上争中午,说明大气颗粒物的来源包括天然源和人为源.     

区域规划环评中大气环境监测点位布设研究

探讨了大气环境监测点位的布设方法,在区域规划环境影响评价布设大气监测点位时,应综合考虑开发区的功能区划分、区内产业分布及环境敏感点分布等情况;结合规划区内外现状及规划实施后重点污染源的位置及排放高度,根据区域污染气象条件,采用Gauss模式预测最大浓度落地点,并以此作为区域大气环境监测点的布设依据.对某区域开发规划案例进行了大气环境监测点位布设研究,通过实践,该布设方法不仅可以反映区域大气环境质量现状的空间分布特征,而且可以为区域大气环境预测提供良好的数据支持,为优化区域规划提供依据;同时,对规划后的污染源最大浓度落地点的监测,可以为单个项目的环境预测提供背景值,起到简化入区建设项目环评的作用.     

小风和静风状态下连续体源大气扩散模式的理论推导

以小风和静风状态下连续点源的大气扩散模式为基础,采用与体源烟团的初始分布尺度相当的初始时间修正其扩散参数公式中的运行时间,从理论上导出了小风和静风状态下连续体源的大气扩散模式。该模式与现有的大气扩散模式体系完全相容,可以方便地应用于小风和静风状态下连续体源引起的地面浓度的预测计算。     

A modified steady-state model for evaluation of ammonia concentrations behind a water curtain

Water curtain system has been proved an effective mitigation measurement for ammonia spill dispersion. Calculating of ammonia cloud concentration with water curtain was less studied. This paper presents a steady-state calculation model to calculate open and forced ammonia spill dispersion. The formula of ammonia absorption was built and integrated into the calculation model. The calculated downwind ammonia concentrations for open and forced spill dispersion were reproduced and compared with literature using a statistical method. In addition, the relationship between ammonia concentration in water droplet and the droplet diameter was studied. The results display that the formula of ammonia absorption is suitable for calculating mass transfer process between the ammonia cloud and the water curtain. The calculation model presents good performances for open and forced ammonia spill dispersion. This study indicates that the calculation model can be satisfactory in determining the impact of open and forced ammonia spill dispersion and the design of water curtain mitigation system.     

Particulates pollution management and economic analysis of small rural enterprises in mountain areas: A case study of Wenquan town in China

At present, many rural enterprises in China's mountainous areas are developing rapidly, and due to poor planning and improper management, in an uncontrolled manner. These small enterprises are making atmospheric pollution far more serious and more difficult to control than before. Thus, as is the case with most developing countries, China is facing the challenge of managing the increased environmental pollution that is accompanying its economic development. This paper examines the case of cement dust pollution in the town of Wenquan in Sichuan province in order to determine how to adjust the relationship between development of rural enterprises and atmospheric environmental pollution in mountainous areas. Using the single objective linear programming method, and based on the principle of overall optimization, an optimal control plan for different pollution sources was worked out and an economic assessment on reclamation of cement dust was completed. According to our analysis, after implementation of this plan for four years, two months, the concentrations of suspended particles in Wenquan will achieve the requirement of the national third-order ambient air quality standard; the current serious dust pollution will be completely controlled; and the reclamation of cement dust will totally compensate for the cost of dust control and will result in 92,000 yuan of pure profit per year. At that time, the economy and environment will be in harmony.     

大气环流异常与地震关系初探

本文以海城、乌恰地震为例分析了我国强震前特大干旱的大气环流特征。表明强地震前的气象异常是显著的，且大气环流相对于多年平均环流具有明显的干旱特征，从而揭示了地震与大气环流异常之间的相互联系，这对提高强地震中长期预测的准确率有一定实际意义。     

Regional differences in mercury levels in aquatic ecosystems: A discussion of possible causal factors with implications for the Tennessee river system and the Northern Hemisphere

Concern about mercury pollution from atmospheric deposition has risen markedly in the last decade because of high levels of mercury in freshwater fish from relatively pristine waters. Whereas high concentrations have been found principally in Canada, the northern United States, and Scandinavia, they have also recently been observed throughout much of Florida. Recent surveys of the Tennessee River system, however, have found no locations where fish levels exceed EPA guidelines for fish consumption. This paper evaluates a number of factors that may cause certain regions in the northern hemisphere to experience unacceptable fish mercury levels while other regions do not. Relevant regional differences include: (1) Waters of the Tennessee River system are generally nonacidic (pH>6) and well buffered, whereas 16%, 22%, and 40% of the lakes in upper Midwest, Northeast, and Florida, respectively, have acid-neutralizing capacities below 50 μeq/liter. Acidity correlates highly with fish mercury levels in a number of lake surveys, and experimental manipulations of acidity have significantly raised fish mercury levels. (2) The ratio of land area to water surface area in the Tennessee Valley averages about 30, whereas it is 15 in the upper Midwest and 6 in Florida. Low ratios allow mercury in precipitation to be directly deposited to aquatic bodies, without an opportunity for the mercury to be sequestered by terrestrial ecosystems. (3) Stream organic matter concentrations in Florida, the upper Midwest, and Sweden are 2–10 times those in the Tennessee Valley. Mercury binds strongly to organic matter, and organic matter transport in runoff is a major pathway by which mercury enters aquatic ecosystems.