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41.
The groundwater regime in the north‐western part of the Visakhapatnam urban area was polluted as early as 1981 by discharge of untreated industrial effluent from a Hindustan Polymers Limited (HPL) plant. A total dissolved solids (TDS) concentration of surficial effluent up to 6500 mg/l and of groundwater in the range 3000–4200 mg/l has been reported in the environs of the HPL plant during May 1992. Groundwater occurs under water table conditions. The groundwater flow model was simulated as a single layer aquifer, using MODFLOW and FLOWPATH computer models. Aquifer parameters were estimated and the value of effective porosity assumed. The water table configuration was mapped in May 1981 using 33 observation wells. The calibrated hydraulic head distribution was used to compute the velocity field using the effective porosity values. The flow paths of groundwater migration from the source locations up to 2002 AD were predicted. Pathlines of particles in the groundwater indicated a predominant north‐east and south‐west migration of groundwater pollution in the area. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
42.
辽宁中部城市群大气能见度变化趋势及影响因子分析 总被引:38,自引:5,他引:33
通过分析辽宁中部相对集中分布的5个城市群1987-2002年间的大气能见度、影响能见度的气象因子和污染物的变化特征及能见度与气象因子、污染物浓度之间的相关关系等,得到以下结论:(1)各城市能见度有明显的月、季和年际变化特征,能见度月变化呈双峰型,第一个峰值在5月份,第二个峰值在9,10月份;冬季能见度的值最低,春、秋季高;本溪市的能见度在逐年变好;沈阳的能见度从1987-1997年逐年变好,1997年以后又逐年变差;其它城市的能见度呈逐年变差的趋势。(2)各城市影响能见度的气象因子的年际变化特征基本是一致的;5个城市TSP,SO2污染浓度年均值均呈下降趋势,NOx的年际变化趋势不明显。(3)能见度与湿度、雾的相关关系都呈负相关且非常显著;与降雨量、风速及温度之间的关系比较复杂;与各种污染物的相关都呈负相关。 相似文献
43.
Models-3空气质量模式对兰州市污染物输送的模拟 总被引:23,自引:7,他引:16
较详细地介绍了美国环保总局的第三代空气质量模式系统Models-3的特点,并且针对兰州市冬季采暖期污染严重的特点,选取2002年12月份的个例,将兰州市最新的大气污染源资料加入模式中.对模式进行调试并检验了该模式对兰州污染的模拟性能。从模式对SO2,NO2和O3等几种大气污染物浓度的模拟结果与监测资料对比分析,表明该模式系统较好地模拟出了SO2,NO2的空间分布格局,模拟结果与监测结果比较吻合,而且模式模拟的污染物浓度场比较均匀;模式模拟的O3的日变化规律与资料分析结论基本一致,也符合O3的生成机理。因此该模式系统对于复杂地形条件下的城市污染物输送具有一定的模拟能力。 相似文献
44.
45.
桂林甑皮岩洞穴遗址地下水示踪及污染来源分析 总被引:7,自引:7,他引:0
桂林甑皮岩遗址周围地带地下水中污染物的种类及来源复杂。为了查明地下水系统的结构特征,分析地下水的污染物运移路径和追溯污染源,采用在线高分辨率示踪技术与人工采样相结合的方法。选取荧光素钠和罗丹明B两种示踪剂,在桂林甑皮岩遗址周围进行了三次示踪试验。根据试验结果分析地下水流场,计算地下水平均流速。结果表明地下水流速在1.6~33.91 m/d,平均值为12.92 m/d。流场内岩溶以溶蚀裂隙为主,且裂隙发育呈网络式,存在西北向东南方向的主径流带,但大型岩溶管道存在的可能性小。三次示踪试验结果均显示,投放点所在的污染源区与遗址周围地下水存在水力联系,因此,遗址附近的居民小区、学校、原砖厂等污染源对遗址下部的地下水存在潜在污染,需更大程度地划分遗址的保护范围。特别是甑皮岩景区化粪池密闭情况较差,严重危害遗址环境,必须对化粪池进行防渗处理。 相似文献
46.
The lignite coal researched by this study was subjected to a two‐stage activation process performed in the scope of obtaining active carbon from domestic resources. “Activation” and “carbonization” stages were used in the experiments. The modified lignite was produced by impregnating lignite with KOH and washing the activation product with 15% HCl solution after thermal treatment. Increasing KOH dosage also increased the removal efficiency. The variables investigated in adsorption experiments were contact time, initial concentration, pH, and sorbent dosage. Adsorption kinetics was fitted by using the pseudo‐first‐order equation, pseudo‐second‐order equation, and intra‐particle diffusion. Isotherm modeling was carried out using Langmuir, Freundlich, and Dubinin–Radushkevich equations. Selected target compound in this work is common environmental pollutant in waters. A commonly known effect of chloroform is its carcinogenic effect. Therefore, removal of these compounds from water is considerably important. Chloroform removal of 97% for was achieved by the use of Konya region activated lignite. 相似文献
47.
Microplastics as contaminants in the marine environment: a review 总被引:15,自引:0,他引:15
Since the mass production of plastics began in the 1940s, microplastic contamination of the marine environment has been a growing problem. Here, a review of the literature has been conducted with the following objectives: (1) to summarise the properties, nomenclature and sources of microplastics; (2) to discuss the routes by which microplastics enter the marine environment; (3) to evaluate the methods by which microplastics are detected in the marine environment; (4) to assess spatial and temporal trends of microplastic abundance; and (5) to discuss the environmental impact of microplastics. Microplastics are both abundant and widespread within the marine environment, found in their highest concentrations along coastlines and within mid-ocean gyres. Ingestion of microplastics has been demonstrated in a range of marine organisms, a process which may facilitate the transfer of chemical additives or hydrophobic waterborne pollutants to biota. We conclude by highlighting key future research areas for scientists and policymakers. 相似文献
48.
49.
The bacteria and plants were associated to remove diesel oil pollutants from soil.Three efficiently degrading bacteria(named strains Q10,Q14 and Q18,respectively) were isolated.Two plants(alfalfa and Indian mustard) were selected to form the association.Biodegradation of diesel oil pollutants in soil was accelerated by bacteria-plants association.The main results are summarized as follows.The plants-bacteria association was more effective in biodegradation of diesel oil pollutants in soil than in respective experiments carried out with plants or bacteria alone.Strain Q18-Indian mustard association resulted in the maximum diesel oil reduction(69.18%).The activities of catalase and polyphenol oxidase in soil were enhanced and microbial populations in soil,especially in rhizosphere,were also stimulated in the treatment of bacteria-plant association.Overall,the soil conditions might be improved by alfalfa or Indian mustard to benefit the growth of bacteria,which resulted in degradation of diesel oil pollutants more effective by the bacteria-plant association.The bacteria-plants association may be a better approach to the removal of diesel oil pollutants from soil. 相似文献
50.