污染场地土壤重金属分布特征及修复技术研究

重金属在污染场地土壤中的分布具有不均匀性和多样性,降低了土壤重金属分布特征的获取精度。为优化土壤修复效果,提出污染场地土壤重金属分布特征及修复技术研究。该技术首先确定研究目标区域概况,基于分析结果确定采样点位置布设采样点;根据采样样本检测重金属元素浓度含量,提取土壤重金属分布特征;最后根据提取的特征,选取微波强化[S,S]-乙二胺二虎珀酸淋洗方法作为土壤重金属污染修复方法,完成土壤重金属污染修复。研究结果表明,使用该技术完成土壤在重金属污染修复时,能够将污染场地重金属污染浓度有效降低,修复效果好。

永煤塌陷区水污染对鲫鱼过氧化氢酶和乳酸脱氢酶活性的影响

2010年5月,选择永城煤矿塌陷区天然鱼塘的野生鲫鱼(Carassius auratus)为对象,以相对无煤矿污染的商丘市天沐湖为对照,研究了永城煤矿塌陷区低浓度混合重金属污染对鲫鱼血液过氧化氢酶(CAT)和血清乳酸脱氢酶(LDH)活性的影响。结果表明,永城煤矿塌陷区鲫鱼CAT的OD值(0.600)极显著高于天沐湖鲫鱼CAT的OD值(0.411)(P<0.01),塌陷区鲤鱼血清中LDH的OD值(0.310)极显著低于天沐湖鲫鱼CAT的OD值(0.421)(P<0.01),说明煤矿塌陷区低浓度混合重金属污染对鲫鱼的正常生理过程有明显的抑制。

Biosorption of Cr(Ⅳ),Cr(Ⅲ),Pb(Ⅱ) and Cd(Ⅱ) from Aqueous Solutions by Sargassum wightii and Caulerpa racemosa Algal Biomass

Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr（VI）,Cr（III）,Pb（II） and Cd（II） by algal biomass obtained from algae Sargassum wightii（brown） and Caulerpa racemosa（green）.Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr（VI）,Cr（III）,Pb（II） and Cd（II） ions.C.racemosa exhibited 85% biosorption of Cd（II） and Cr（VI）,and 50% biosorption of Cr（III） and Pb（II）.The results of our study suggest that seaweed biomass can be used efficiently for

Heavy Metal Distribution Map in Soil by Using GIS Techniques

A detailed investigation was conducted to understand the contamination characteristics and distributions of heavy metal pollution in terms of contributions of the heavy metal concentrations as mg/kg ofCd, Cr, Cu, Ni, Zn, Pb, Fe and Mn in the urban soil in Eskisehir city center. The amount of these heavy metals were determined from 15 soil sample points collected within urban area and every sample point included 6 separated samples for chemical analyses. The results indicated that concentration values of all metals except Ni and Cr in soils were below the risky limit pollution values which are recommended by Turkey Ministry of Environment and Forestry in some sample points. Spatial distribution maps were created and recoded, in terms of these heavy metals concentrations as contribution to heavy metal pollution in soil, through Geographical Information Systems techniques. As a result, risky areas were modeled in terms of contamination of heavy metal and it is shown that, every different risky area can be interpreted based on buildings in city center quickly and easily.

Removal of Heavy Metals （Copper, Manganese and Zinc） from Industrial Wastewater of Baiji Refinery by Granular Activated Carbon

The aim of the present work is to remove heavy metals （copper, manganese, and zinc） from industrial wastewater of Baiji refinery using GAC （granular activated carbon）. The most important factors affecting adsorption process have been studied, which are granular activated carbon thickness, H, inlet pollutant concentration, Cv, and liquid hourly space velocity, LHSV. All experiments were performed under constant temperature at 25℃ and pH = 7. The experimental apparatus was designed and constructed to enable controlling of the operating conditions. Employing five levels for each of H and LHSV and three levels for Co required 75 runs for each metal. Box-Wilson method was used to reduce the number of experiments to 15 for each metal. The results indicated that copper, manganese, and zinc can be completely removed from wastewater using activated carbon. However, breakthrough time for zinc is low. It is also shown that breakthrough time （TB） and exhaustion time （TE） are inversely proportional with pollutant concentration and LHSV （liquid hour space velocity） while it is directly proportional with the thickness of activated carbon column.

Comparison of Mosses as Bioindicator of Heavy Metal Pollution in Aramoko-Ekiti and Are-Ekiti, Nigeria

The increasing global concern over the public health impacts attributed to environmental pollution led us to investigate and compare the deposition of some heavy metals in mosses from an urban area, Aramoko Ekiti and a rural area, Are Ekiti. Both towns are located in the SouthWest, Nigeria. Moss samples were collected at different sites in the two towns. These samples were then digested in acid and analysed for Cd, Cr, Ni, Pb and Cu, using a flame atomic absorption spectrometer. The results of the study show variations in the concentrations of the heavy metals among the different sites in each town as well as between the two towns. Apart from cd which was suspected to have originated from natural sources in the investigated samples, the relatively higher concentrations of the other metals in Aramoko-Ekiti suggests an important anthropogenic source which we suspect to be automobiles since there are little or no industrial or mining activities within the town. Furthermore, the relatively higher concentrations of the metals exhibited by moss samples collected around locations prone to higher traffic situations in the two towns such as roadsides, filling stations and garages stresses the significance of traffic density in heavy metal pollution of the environment. These places （filling stations and garages） should be sited far away from residential areas. Also, residences should be sited at considerably far distances from major roads. These will prevent the bioaccumulation of the heavy metals in residents. Though, the results show that Aramoko-Ekiti is more polluted with the heavy metals than Are-Ekiti, the concentration of the heavy metals were still within the permissible limits. Given the results of this work and similar ones, there is need to evaluate the pollution status of the environment from time to time especially the urban areas and high traffic areas.

Characterization of Suspended Solids and Heavy Metal Distributions during First Flush in Highway Runoff

Nonpoint source pollution has gradually received attention during stormwater flush in highway runoff. The understanding the pollutant characteristics will be criticat issue to treat these types of pollution. In the present study, two monitoring stations were selected to measure hydrology and to take sampling during first flushing events at the Zhong-Shan freeway and East-West expressway in the Miaoli County, Taiwan. The results of monitoring stations in 2007 storm events found that normally the peak concentrations of total suspended solids （TSS） and heavy metals occurred at the initial stormwater and then the concentrations decreased when the measured time elapsed. The highest and lowest heavy metal concentrations were Fe and Ni, respectively, during the stormwater. Particle size distribution （PSD） mostly ranged from 12μm and 96 μm at two measured sites. The event mean concentrations （EMCs） and loadings of TSS and heavy metals were also correlated with total runoff and total rainfall.

Evaluation of Metal Contamination of Mullet （Mullus surmuletus L., 1758） in the Bay of Oran

The present study focused on the evaluation of the contamination by three heavy metals （Cd, Cu and Zn） of a bony fish, Mullus surmuletus L., 1758, caught in the Bay of Oran. This reflects the quality of fish habitat as species common Algerian coastal waters and enjoyed by a large fish-eating population. Monthly sampling was spread over a period of six months （December 2011-May 2012）. Given their physiological importance in the body, muscle, liver and gonads were targeted. Metal concentrations were determined by atomic absorption spectrophotometry in flame depends on three parameters （sex, size and month）. It appears from this study that the target organs of rouget （M. surmuletus） accumulate three metal pollutants sought. The highest values are those of zinc, copper and cadmium are at concentrations at least important. The results, statistically treated, showed no significant difference between the concentrations of trace metals both sexes and at all three organs considered. The average dose of heavy metals found in the mullet compared to those provided by the literature relating to DMA （Maximum Allowable Doses）, are not worrisome. Concentration levels of toxic metals reflect a certain metal pollution in the Bay of Oran.

The Assessment of Air Pollution during 2013 and 2014 in Tokat Province

This study aimed to determine the amount of total polluting matter emitted into the atmosphere from heating and industrial-based emissions and the total pollution bulk of Tokat city center. The annual cycles of some heavy metal in particulate matters have been investigated at this area in order to elucidate temporal variations as well as major sources processes responsible for their formation. Air particulate samples were collected from three different locations situated around Tokat. These samples were determined for heavy metals by using Flame or graphite-furnace Atomic absorption spectroscopy. Particulate matter concentrations up to 52.43μg/m^3 were observed in sampling area. The initial results of the chemical analysis showed that concentration values of heavy metals in air particles observed were higher than the World Health Organization （WHO） guideline limit values.

Heavy Metal Contamination of Agricultural Soils in Taiyuan, China

To evaluate the current state of the environmental quality of agricultural soils in Taiyuan City, a hotspot for China's industrial development, the concentrations of 8 heavy metals in soils were investigated by means of extensive sampling in farmlands, forestlands,and grasslands in the city. Statistical analyses and spatial distribution maps were used to identify the most significant heavy metal pollutants. The mean concentrations of As, Cd, Cu, Hg, Pb, Zn, Ni, and Cr were slightly higher than their background values in Taiyuan's topsoil, but were lower than the maximum permissible concentrations in the Chinese Environmental Quality Standard for agricultural soils. Farmland soils in Taiyuan had the highest average Cd, Cu, Hg, Pb, Zn, and Cr concentrations, but the As and Ni concentrations did not differ significantly among the farmland, forestland, and grasslands. Soil contamination by Cd, Cu, Hg, Pb,Zn, and Cr was mainly derived from farming practices, especially the use of sewage water for irrigation. In contrast, As and Ni might derive mainly from the soil parent material. The identification of heavy metal sources in agricultural soils may provide a basis for taking appropriate action to protect soil quality.

Spatial Distribution Patterns and Potential Sources of Heavy Metals in Soils of a Crude Oil-Polluted Region in China

Twenty-two soil samples were collected at the subregional scale （50 km2） around Gudao Town, a typical oil-producing region of the Shengli Oilfield in the Yellow River Delta, China to determine the spatial distribution patterns and potential sources of heavy metals in soils of crude oil-polluted regions. The concentrations of total petroleum hydrocaxbons （TPHs） and heavy metals as well as other soil properties were determined and the enrichment factor values were calculated for the heavy metals measured. Principal component analysis （PCA） and cluster analysis （CA） were used to estimate potential sources contributing to the concentrations of heavy metals in the soils. The results revealed that the soils were slightly alkaline （pH = 7.33-8.05） and high in salinity （1.43-41.30 g kg-1）, TPHs （0.51 28.40 g kg-1） and organic matter （1.74-31.50 g kg-1）. The mean concentrations of the measured heavy metals Cu, Zn, Pb, Cd, Cr, Ni and V were 18.4, 78.2, 20.8, 0.19, 56.6, 26.3 and 62.1 mg kg-1, respectively. Although the concentrations of all the metals measured in this study were not high enough to exceed the national control standards, there was a significant enrichment of Cd in the study area and Zn and Ni were in the category of deficiency to minimal enrichment. The spatial distribution patterns of Cu, Cr, Ni and V were similar and partially affected by oil exploitation and petroleum hydrocarbon spills. Potential sources of Cr, Ni, V and Cu in the soils were both natural sources and petroleum hydrocarbon spills, while Zn, Pb and Cd were probably from anthropogenic sources such as farming activities and traffic.