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21.
Thomas B. Boving Mark H. Stolt Janelle Augenstern Brian Brosnan 《Environmental Geology》2008,55(3):571-582
The control of polluted surface runoff and the assessment of possible impacts on groundwater is a concern at the local and
regional scale. On this background, a study investigates possible impacts of organic and inorganic pollutants (including bacteria)
originating from a permeable asphalt parking lot on the water quality immediately beneath it. The functioning of the permeable
pavement, including clogging and restricted vertical percolation, was also evaluated. Four nested sample ports (shallow and
deep) were installed below low- and high-traffic areas, including one port outside the parking lot. At least initially there
was a good hydraulic connection between the parking surface and the shallow sample ports. The presence of a geotextile layer
at the base of the parking lot structure, however, was identified in lab tests as one factor restricting vertical percolation
to the deeper ports. Clogging of the permeable surface was most pronounced in heavy traffic areas and below snow pile storage
areas. Corroborated by high electric conductivity and chloride measurements, sand brought in by cars during winter was the
principal cause for clogging. No bacteria or BOD were found in percolating water. Polycyclic aromatic hydrocarbons (PAH) were
present at concentrations near minimum detection limit. Nutrients (nitrate and phosphate) were being leached into the ground
via the permeable parking lot surface at annual flux rates of 0.45–0.84 g/m2/year. A multi-species tracer test demonstrated a retention capacity of the permeable parking lot structure of >90% for metals
and 27% for nutrients, respectively. 相似文献
22.
Ibticem Chamtouri Habib Abida Hafedh Khanfir Salem Bouri 《Environmental Geology》2008,55(5):1123-1133
Groundwater in Sfax City (Tunisia) has been known since the beginning of the century for its deterioration in quality, as
a result of wastewater recharge into the aquifer. An average value of 12 × 106 m3 of untreated wastewater reaches the groundwater aquifer each year. This would result not only in a chemical and biological
contamination of the groundwater, but also in an increase of the aquifer piezometric level. Quantitative impacts were evaluated
by examining the groundwater piezometric level at 57 surface wells and piezometers. The survey showed that, during the last
two decades, the groundwater level was ever increasing in the urban area with values reaching 7 m in part; and decreasing
in Sidi Abid (agricultural area) with values exceeding −3 m. Groundwater samples for chemical and microbial analysis were
collected from 41 wells spread throughout the study area. Results showed significantly elevated levels of sodium, chlorides,
nitrates and coliform bacteria all over the urban area. High levels (NO3: 56–254 mg/l; Na >1,500 mg/l; Coliforms >30/100 ml) can be related to more densely populated areas with a higher density
of pit latrine and recharge wells. Alternatively results showed a very variable chemical composition of groundwater, e.g.
electrical conductivity ranges from 4,040 to19,620 μs/cm and the dry residual varies between 1.4 and 14 g/l with concentrations
increasing downstream. Furthermore a softening of groundwater in Set Ezzit (highly populated sector) was observed. 相似文献
23.
M. Irfan Yesilnacar Erkan Sahinkaya Muhsin Naz Bestamin Ozkaya 《Environmental Geology》2008,56(1):19-25
Monitoring groundwater quality by cost-effective techniques is important as the aquifers are vulnerable to contamination from
the uncontrolled discharge of sewage, agricultural and industrial activities. Faulty planning and mismanagement of irrigation
schemes are the principle reasons of groundwater quality deterioration. This study presents an artificial neural network (ANN)
model predicting concentration of nitrate, the most common pollutant in shallow aquifers, in groundwater of Harran Plain.
The samples from 24 observation wells were monthly analysed for 1 year. Nitrate was found in almost all groundwater samples
to be significantly above the maximum allowable concentration of 50 mg/L, probably due to the excessive use of artificial
fertilizers in intensive agricultural activities. Easily measurable parameters such as temperature, electrical conductivity,
groundwater level and pH were used as input parameters in the ANN-based nitrate prediction. The best back-propagation (BP)
algorithm and neuron numbers were determined for optimization of the model architecture. The Levenberg–Marquardt algorithm
was selected as the best of 12 BP algorithms and optimal neuron number was determined as 25. The model tracked the experimental
data very closely (R = 0.93). Hence, it is possible to manage groundwater resources in a more cost-effective and easier way with the proposed
model application. 相似文献
24.
Liugen Zheng Guijian Liu Lei Wang Chen-Lin Chou 《Journal of Geochemical Exploration》2008,97(2-3):59-68
The Huaibei Coalfield, Anhui Province, China, is one of the largest coalfields in China. The coals of Permian age are used mainly for power generation. Coal compositions and 47 trace elements of the No. 10 Coal of the Shanxi Formation, the No. 7, 5, and 4 Coals of the Lower Shihezi Formation, and the No. 3 Coal of the Upper Shihezi Formation from the Huaibei Coalfield were studied. The results indicate that the Huaibei coals have low ash, moisture, and sulfur contents, but high volatile matter and calorific value. The ash yield increases stratigraphically upwards, but the volatile matter and total sulfur contents show a slight decrease from the lower to upper seams. Magmatic intrusion into the No. 5 Coal resulted in high ash, volatile matter, and calorific value, but low moisture value in the coal. Among the studied 47 trace elements, Ba, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Th, U, V, and Zn are of environmental concerns. Four elements Hg, Mo, Zn, and Sb are clearly enriched in the coals as compared with the upper continental crust. 相似文献
25.
K. Vinod kumar R. C. Lakhera Tapas R. Martha R. S. Chatterjee A. Bhattacharya 《Environmental Geology》2008,55(4):789-799
Mass movements such as landslides in mountainous terrains are natural degradation processes and one of the most important
landscape-building factors. Varunawat Parbat overlooking Uttarkashi town witnessed a series of landslides on 23 September
2003 and the debris slides and rock falls continued for 2 weeks. This landslide complex was triggered due to the incessant
rainfall prior to the event, and its occurrence led to the blockage of the pilgrim route to Gangotri (source of the Ganges
river) and evacuation of thousands of people to safer places. Though there was no loss of lives due to timely evacuation,
heavy losses to the property were reported. High-resolution stereoscopic earth observation data were acquired after the incidence
to study the landslide in detail with emphasis on the cause of the landslide and mode of failure. Areas along the road and
below the Varunawat foothill region are mapped for landslide risk. It was found that the foothill region of the Varunawat
Parbat was highly disturbed by man-made activities and houses are dangerously located below steep slopes. The potential zones
for landslides along with the existing active and old landslides are mapped. These areas are critical and their treatment
with priority is required in order to minimise further landslide occurrences. 相似文献
26.
乌鲁木齐河流域地下水水质监测网设计 总被引:1,自引:0,他引:1
文章运用地下水易污性编图及污染源分布图法进行了乌鲁木齐河流域地下水水质监测网设计。共设计了130监测孔,现有46个监测孔,另需要84个新的监测孔。按监测类型分为面源监测点22个,点源监测点87个,重点水源地与泉水监测点21个。按监测运行分长期监测点55个,流域普查监测点75个。普查监测点监测频率为1次/5年,长期监测点监测频率为1次/年。首期有针对性地在污染严重的柴窝堡新化厂排污区、乌鲁木齐河谷老排污区、米泉污灌区、米泉工业污染区、老龙河污染区取了25个污染水样测试分析,结果显示地下水已经受到严重污染。 相似文献
27.
吉林省龙岗火山群南龙湾第四纪火山碎屑颗粒特征研究 总被引:2,自引:0,他引:2
爆炸性火山喷发形成的碎屑颗粒的粒度、分选性、表面结构和内部结构等特征与火山喷发的机制、岩浆与水作用的程度、搬运过程等有着重要的联系。本文以此为线索,研究了龙岗火山群南龙湾火山的一个剖面,以探讨其喷发类型和特征。在该剖面上采集了不同层位火山碎屑颗粒样品,然后进行显微形貌观测、粒度分析和扫描电镜形貌观测。显微镜下观测表明,射汽爆发、射汽岩浆爆发和岩浆爆发的碎屑颗粒具有不同的成分和形貌特征。粒度分析结果显示,粒度与喷发类型之间存在很好的对应关系,不同的爆发类型具有不同的分维值D范围。SEM分析可以提供有关火山喷发特征对火山碎屑颗粒的影响。本文的研究结果表明,南龙湾火山喷发为爆炸式喷发,包括早期的射汽岩浆爆发,到岩浆爆发至晚期以射汽爆发为主的射汽岩浆爆发的不同阶段,该区火山喷发的不同时期,水参与喷发的程度不同。 相似文献
28.
根据 2 0 0 1年 2月和 7月对崎岖列岛附近海域的水质和底质表层沉积物调查结果 ,采用环境质量单项评价标准指数法 ,对该海域环境质量现状进行了评价与分析。结果表明 :(1 )该海域水质的 p H值、溶解氧和石油类等环境因子基本符合一类海水水质标准 ,化学需氧量、活性磷酸盐和无机氮浓度则超标严重 ,该海域水质已处于严重富营养化状态 (夏季比冬季富营养化程度略低 ) ;(2 )该海域底质表层沉积物中除部分站位的重金属 Cu、 Zn含量超标外 ,有机质、石油类和重金属 Pb、 Cd、 Hg的含量均未超标 ,底质环境状况尚好 相似文献
29.
30.
本文以南麂海洋站1983~1990年风、浪的实测资料为依据,建立了南麂海城春、夏、秋、冬季定常波风浪波高与风速的经验关系式。检验结果表明,曲线回归显著,计算值与实测值吻合良好。文中还对偏NNE向和偏SSW向计算波高随风速增大的快慢,同一方向在同一风速作用下计算波高的季节变化及其机理作了初浅的讨论。 相似文献