过硫酸盐在岩溶管道地下水中的稳定性及其对苯系物的去除效果

原位化学氧化(in situ chemical oxidation,ISCO)是一种高效便捷的去除地下水有机污染物的技术,相比于多孔介质,岩溶地下河中ISCO技术应用还未见报道.为了更好地认识ISCO技术在岩溶地下河石油污染修复中应用的可行性,使用过硫酸盐(persulfate,PS)作为化学氧化剂,在实验室利用碳酸盐...     

生活垃圾填埋场对地下水污染的风险评价——以北京北天堂垃圾填埋场为例

以国外生活垃圾填埋场对地下水污染的风险评价方法为基础,建立了综合考虑含水层脆弱性及生活垃圾填埋场自身性质的地下水污染风险评价方法,并以北京北天堂垃圾填埋场为例.评价了当地4个生活垃圾填埋场对地下水污染的风险级别.结果表明,生活垃圾填埋场对地下水污染的风险取决于场地规模、防护情况等自身相关参数以及场地所处位置的含水层脆弱...     

以河砂为填料的接触氧化法处理高铁锰地下水研究

分别选用河砂、锰砂、改性页岩3种滤料作为滤柱填料,采用接触氧化法去除地下水中的铁锰,通过对比实验选取最佳填料,并对最佳填料去除铁锰的影响因素进行了研究.实验结果表明,3种滤料成熟期基本相同且对铁锰均有较好的去除效果,由于河砂具有广泛易得、成本低廉等优点,因此更适用于小城镇地区使用.对以河砂为填料的接触氧化法除铁除锰的深...     

运用改进综合评分法筛选典型污染物的研究——以大武水源地地下水典型污染物筛选为例

结合潜在危害指数法和综合评分法筛选大武水源地地下水典型污染物。鉴于潜在危害指数法不考虑污染物的环境浓度,将潜在危害指数作为综合评分法的评价指标之一,同时引进污染物的检出频率、生物降解性、生物累积性、研究区是否有污染源检出、是否为环境激素、是否为美国环境保护署(EPA)优先有机污染物、是否为中国优先污染物、是否为持久性有机污染物等指标,计算不同污染物的综合得分,再通过聚类分析,筛选出典型污染物。研究结果表明,大武水源地地下水典型污染物为三氯甲烷、三氯乙烯、四氯乙烯、四氯化碳和苯。     

老旧无内衬铸铁管中氯对水质的影响

给水管网铁释放对于饮用水水质具有重要影响。通过浸泡实验和烧杯实验探究实际老旧无内衬铸铁管中氯对铁腐蚀的影响。一方面,通过实际管段浸泡实验,对比了不同初始氯浓度下管道中水质变化,发现在高初始氯下浊度和三磷酸腺苷增大,这表明在铁释放严重的无衬里铸铁管道中,消毒剂的增加可能引发水质微生物风险;另一方面,通过烧杯实验进一步确认了氯对管网颗粒物结构的影响,发现氯能够通过降低颗粒物表面电荷导致静电排斥降低,从而加剧了颗粒物的团聚,导致粒径变大、浊度升高,且颗粒物对消毒副产物三卤甲烷具有一定的富集累积作用,引发水质化学风险。本研究结果可为了解给水管网中氯引发的黄水风险提供参考。     

水相和泥浆系统中地下水成分对高锰酸钾氧化TCE的影响

三氯乙烯(TCE)是污染土壤和地下水中检出率较高的氯代有机物。以TCE为研究对象,考察了地下水无机成分和腐殖酸对高锰酸钾氧化TCE的影响,研究了不同离子强度下的MnO2颗粒行为,并测定了泥浆系统中TCE的氧化效果,结果表明:当TCE初始浓度为20 mg/L、高锰酸钾与TCE的摩尔比为2∶1,离子浓度+、Cl-、HCO3-对TCE的去除率影响甚微,但离子强度对MnO2的沉淀生成影响显著;0.1 mol/L的K+对TCE的去除有一定程度的抑制;0.1 mmol/L的Fe2+和腐殖酸对TCE的氧化有显著负面影响。泥浆系统实验进一步验证了有机质对高锰酸钾氧化TCE的影响很大。     

地下水中二价锰对成熟石英砂滤层去除氨氮的影响

在中试条件下,考察了地下水中二价锰离子（Mn2+）对成熟石英砂表面滤膜去除氨氮（NH4+-N）的影响。结果表明,当进水Mn2+浓度不大于3.5 mg·L-1时,NH4+-N去除率随进水Mn2+浓度增大而增大。相应地,Mn2+的存在使得进水NH4+-N的浓度上限由2.51 mg·L-1提高到2.83 mg·L-1,且NH4+-N和Mn2+可实现同步去除。此外,进水Mn2+的存在（（2.1±0.1）mg·L-1）使得去除NH4+-N所需要的温度下降,这说明Mn2+对石英砂表面复合氧化膜催化NH4+-N氧化具有一定的促进作用,从而提高了NH4+-N在滤柱中的去除速率。     

以养殖废水为底料的微生物燃料电池产电性能与水质净化效果

以养殖场沼泥为接种物,构建了乙二胺、三氯化铁改性碳毡阳极的单室无膜微生物燃料电池,探讨了2种阳极改性电池的产电规律,考察了其去除养殖废水中COD、氨氮的效果以及臭味的表观性状变化。结果表明,以葡萄糖为底物时,乙二胺、三氯化铁改性阳极微生物燃料电池在启动20 d和22 d后分别达到稳定,输出电压分别为0.514 V和0.527V(外阻为500Ω),对应输出功率密度分别为332 mW/m2和349 mW/m2。逐渐增大废水投加比例至原水时,2个电池的最大功率密度分别为208 mW/m2和158 mW/m2,COD去除率分别为85%和78%,氨氮去除率分别为52%和45%。此外,养殖废水的臭味去除效果明显。因此,构建的2种改性阳极微生物燃料电池可以利用养殖废水产电,同时使水质得到一定程度的净化。     

不同水温下鲴鱼对铜绿微囊藻的控制作用及对水质的影响

在室内受控模拟条件下开展实验,研究了在19、23、27、31、35℃5个水温梯度下鲴鱼对铜绿微囊藻和水质的影响。研究结果表明,在不同水温下,鲴鱼对铜绿微囊藻具有较强的控制作用,实验结束时铜绿微囊藻密度减少至初始密度的18%~30%,摄食率和消化率分别为6.83×104~8.32×104cells/(g·d)、93%~98%;叶绿素a的去除率为68%~88%;实验组TP、TN去除率分别为22%~25%、20%~38%,对照组的分别为80%~94%、28%~40%。对照组NH+4-N浓度变化很小(0.071~0.073 mg/L),而实验组氨氮浓度显著增大(2.222~3.645 mg/L),分别为初始值的31、34、42、51和46倍。     

Impact of anthropogenic activities on urban stream water quality: a case study in Guangzhou,China

Anthropogenic activities are increasingly impacting the quality of urban surface water, particularly in regions undergoing intensive urbanization, such as Guangzhou of South China with a large urban stream network. To examine such impacts, we conducted field sampling on December 24, 2010, May 24, 2011, and August 28, 2011, representative of the low-, normal-, and high-flow periods, respectively. The first sampling was timed immediately after the closing of the 16th Asian Games (November 12–27, 2010) and the 10th Asian Para Games (December 12–19, 2010) held in Guangzhou. Assessments based on a pollution index method showed that the urban streams under investigation were extremely polluted, with direct discharge of untreated domestic sewage identified as the main pollution contributor. In addition, stream water quality around urban villages with high population densities was worse than that within business districts away from the urban villages. Pollution control measures implemented in preparation for the Asian Games were effective for urban streams within the business districts, but less effective for those adjacent to the urban villages. However, short-term efforts may not be able to achieve sustainable urban water quality improvements. In the case of Guangzhou, minimizing or even eliminating direct point-source inputs to the urban streams is perhaps the best option.     

Health risk assessment of groundwater nitrate contamination: a case study of a typical karst hydrogeological unit in East China

Environmental Science and Pollution Research - Nitrate pollution in rivers, lakes, shallow groundwater, and even deep groundwater occurs in many parts of the world. And, it’s essential to...     

Characterization of shallow groundwater quality in the Lower St. Johns River Basin: a case study

Characterization of groundwater quality allows the evaluation of groundwater pollution and provides information for better management of groundwater resources. This study characterized the shallow groundwater quality and its spatial and seasonal variations in the Lower St. Johns River Basin, Florida, USA, under agricultural, forest, wastewater, and residential land uses using field measurements and two-dimensional kriging analysis. Comparison of the concentrations of groundwater quality constituents against the US EPA’s water quality criteria showed that the maximum nitrate/nitrite (NO _x ) and arsenic (As) concentrations exceeded the EPA’s drinking water standard limits, while the maximum Cl, SO ₄ ^2?? , and Mn concentrations exceeded the EPA’s national secondary drinking water regulations. In general, high kriging estimated groundwater NH ₄ ⁺ concentrations were found around the agricultural areas, while high kriging estimated groundwater NO _x concentrations were observed in the residential areas with a high density of septic tank distribution. Our study further revealed that more areas were found with high estimated NO _x concentrations in summer than in spring. This occurred partially because of more NO _x leaching into the shallow groundwater due to the wetter summer and partially because of faster nitrification rate due to the higher temperature in summer. Large extent and high kriging estimated total phosphorus concentrations were found in the residential areas. Overall, the groundwater Na and Mg concentration distributions were relatively more even in summer than in spring. Higher kriging estimated groundwater As concentrations were found around the agricultural areas, which exceeded the EPA’s drinking water standard limit. Very small variations in groundwater dissolved organic carbon concentrations were observed between spring and summer. This study demonstrated that the concentrations of groundwater quality constituents varied from location to location, and impacts of land uses on groundwater quality variation were profound.     

Investigation of the impacts of tunnel excavation on karst groundwater and dependent geo-environment using hydrological observation and numerical simulation: a case from karst anticline mountains of southeastern Sichuan Basin,China

Environmental Science and Pollution Research - Tunnel excavation has significant disturbance on groundwater system and related geo-environment, especially in karst regions like southwestern China....     

Hydrochemistry of urban groundwater, Seoul, Korea: the impact of subway tunnels on groundwater quality

Hydrogeologic and hydrochemical data for subway tunnel seepage waters in Seoul (Republic of Korea) were examined to understand the effect of underground tunnels on the degradation of urban groundwater. A very large quantity of groundwater (up to 63 million m³ year^− 1) is discharged into subway tunnels with a total length of 287 km, resulting in a significant drop of the local groundwater table and the abandonment of groundwater wells. For the tunnel seepage water samples (n = 72) collected from 43 subway stations, at least one parameter among pathogenic microbes (total coliform, heterotrophic bacteria), dissolved Mn and Fe, NH₄⁺, NO₃⁻, turbidity, and color exceeded the Korean Drinking Water Standards. Locally, tunnel seepage water was enriched in dissolved Mn (avg. 0.70 mg L^− 1, max. 5.58 mg L^− 1), in addition to dissolved Fe, NH₄⁺, and pathogenic microbes, likely due to significant inflow of sewage water from broken or leaking sewer pipes.Geochemical modeling of redox reactions was conducted to simulate the characteristic hydrochemistry of subway tunnel seepage. The results show that variations in the reducing conditions occur in urban groundwater, dependent upon the amount of organic matter-rich municipal sewage contaminating the aquifer. The organic matter facilitates the reduction and dissolution of Mn- and Fe-bearing solids in aquifers and/or tunnel construction materials, resulting in the successive increase of dissolved Mn and Fe. The present study clearly demonstrates that locally significant deterioration of urban groundwater is caused by a series of interlinked hydrogeologic and hydrochemical changes induced by underground tunnels.     

Hydrochemical appraisal of groundwater quality and pollution source analysis of oil field area: a case study in Daqing City,China

Environmental Science and Pollution Research - Serious groundwater pollution not only affects the development of enterprises but also threatens the life and health of residents. To explore the...     

Model comparison for risk assessment: a case study of contaminated groundwater

Many environmental multimedia risk assessment models have been developed and widely used along with increasing sophistication of the risk assessment method. Despite of the considerable improvement, uncertainty remains a primary threat to the credibility of and users' confidence in the model-based risk assessments. In particular, it has been indicated that scenario and model uncertainty may affect significantly the assessment outcome. Furthermore, the uncertainty resulting from choosing different models has been shown more important than that caused by parameter uncertainty. Based on the relationship between exposure pathways and estimated risk results, this study develops a screening procedure to compare the relative suitability between potential multimedia models, which would facilitate the reduction of uncertainty due to model selection. MEPAS, MMSOILS, and CalTOX models, combined with Monte Carlo simulation, are applied to a realistic groundwater-contaminated site to demonstrate the process. It is also shown that the identification of important parameters and exposure pathways, and implicitly, the subsequent design of uncertainty reduction and risk management measures, would be better-formed.     

Comparison of different groundwater vulnerability evaluation models of typical karst areas in north China: a case of Hebi City

Environmental Science and Pollution Research - Groundwater pollution is a serious problem in north China. However, the study on the vulnerability of karst groundwater is mainly in south China, and...     

A new approach for the assessment of groundwater quality and its suitability for irrigation: a case study of the Korba Coastal Aquifer (Tunisia, Africa)

Groundwater is the main source of water in Mediterranean, water-scarce, semiarid regions of Tunisia, Africa. In this study of the Korba coastal aquifer, 17 water wells were studied to assess their suitability for irrigation and drinking purposes. Assessment parameters include pH, salinity, specific ion toxicity, sodium adsorption ratio, nutrients, trace metals pollutants, and fecal indicators and pathogens. Results indicate that salinity of groundwater varied between 0.36 dS/m and 17.4 dS/m; in addition, its degree of restriction is defined as "none", "slight to moderate", and "severe" for 18, 23, and 59% of the studied wells, respectively. To control salts brought in by irrigation waters, the question arises as to how much water should be used to reach crop and soil requirements. To answer this question, a new approach that calculates the optimum amount of irrigation water considering the electrical conductivity of well water (ECw), field crops, and the semiarid meteorological local conditions for evapotranspiration and rainfall is developed. This is applied to the authors' case study area; barley and lettuce were selected among the commonly grown crops because they are high- and low-salinity tolerant, respectively. Leaching requirements were found to be independent of the crop selected, and depend only on the season, that is, 250 to 260 mm/month in the driest season, with a minimum of 47 mm/month though all seasons. A high bacteriological contamination appears in almost all samples. However, if disinfected and corrected for pH, all the well waters can be used for animal farming (including livestock and poultry), although only 29% could be used for human consumption.     

The dynamic links among energy consumption,tourism growth,and the ecological footprint: the role of environmental quality in 38 IEA countries

Environmental Science and Pollution Research - We examine the impact of energy consumption and tourism growth on the ecological footprints and economic growth of 38 International Energy Agency...