Mercury concentrations in environmental media at a hazardous solid waste landfill site and mercury emissions from the site

Mercury (Hg) concentrations in air, effluent water, landfill gas, leachate, groundwater, and soil at a hazardous solid waste landfill site in Korea were measured along with air–soil surface Hg exchange fluxes at the site. The concentrations and fluxes were considerably higher than have been found elsewhere in Korea. Gaseous Hg concentrations in the air peaked during the day, coinciding with Hg being released from the landfill surface. This suggests that air–soil exchange increased the Hg concentrations in the atmosphere. The air–soil exchange flux increased abruptly when solar radiation reached the soil surface. The Hg flux peaked about 3 h before the solar radiation peaked, possibly because reducible Hg was abundant at the soil surface. The Hg emission flux activation energy (E _a) was low, indicating that the Hg species present and Hg–soil binding were probably not as important (because of the high Hg content of the soil) as in previous studies. The methylmercury to total Hg ratios in the discharged effluent, groundwater, and leachate was clearly higher than typically found in coastal water and freshwater, suggesting bacteria caused active methylation to occur under the reducing conditions in the anaerobic landfill. The results suggested that considerable amounts of Hg are probably transported from the landfill to nearby environmental media and that this will continue if waste with a high Hg content continues to be added to the landfill without being pretreated.     

Hazardous waste landfill site selection in Khorasan Razavi Province, Northeastern Iran

The disposal is the final step of any hazardous waste management plan. An inappropriate landfill site may have negative environmental, economical, and ecological impacts. Therefore, landfills should be sited carefully by taking into account various rules, regulations, factors, and constraints. In this study, candidate sites for hazardous landfills in the northeastern Khorasan Razavi province are determined using the integration of geographic information system and landfill susceptibility zonation methods. For this, the inappropriate areas were first removed from the model, and the suitability of remaining regions were evaluated using 15 different criteria in two steps. With this done, nine candidate sites were selected as the most suitable locations. Finally, the selected landfill sites were proposed based on environmental impact assessment (Leopold matrix) and economical studies. This study shows that Maasumabad, Kheirabad, Mayamey, and Yonsi are the best locations for the constitution of landfill in Khorasan Razavi province, respectively.     

Nonlinear site response evaluation of earthquakes: A case study from Sirdjan Balvavard Bridge,Kerman province,Iran

The aim of this study is to illustrate the soil conditions encountered at the proposed bridge sites to analyze and evaluate the test conducted, submit recommendations regarding foundation design. At first by field investigation, the required data was collected and after primary processing the acceptable data was selected. For nonlinear analysis of elastic and rigid half space bed rock, standard hyperbolic model was selected and performed, and the results were compared. The study clearly showed that the effect of bed rock on soil behavior during earthquake is one of the main factors controlling prediction of ground response. A critical aspect of this work was to develop and use a computer code “Abbas Converter” developed by the authors that has several advantages, such as quick installation, acting as a connecter function between the used softwares which can generate the input data corresponding to a defined format and finally, the results of this computer code can be easily exported to the other softwares used in this study. Moreover this code can make it easy to solve the problems encountered.     

Spatial modelling of hazardous elements at waste dumps using geostatistical approach: a case study Sarcheshmeh copper mine,Iran

Mining activities and resulting wastes can be considered as one of the most important sources of hazardous elements in the environment. Knowledge of the spatial distribution of toxic elements in waste dump systems is necessary to assess environmental hazard and strategy. To achieve this goal, this paper investigates spatial distribution of toxic elements using statistical and geostatistical analysis. A total of 58 soil samples were collected, and the amount of As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb and Zn was then determined at “Sarcheshmeh” copper mine waste dumps. In order to evaluate the presence of multivariate outliers, Mahalanobis distance technique (D ²) was applied and the multivariate outlier samples were removed. This resulted in an increase in correlation coefficient. To reduce dimension of data set, principal component analysis was applied and four principal components were determined which indicate 83.463% of the total variance of data set. Estimated PCs together with the toxic elements maps based on the ordinary kriging display aggregation of toxic elements in some parts, and validity of predictions was evaluated using the leave-one-out cross-validation method. The regression coefficients of estimated and observed values presented the reliability of the kriging estimates. Sequential Gaussian simulation method was applied for principal components due to similar results of estimated principal components and toxic elements. The results of simulation maps are almost identical to estimated outcomes.     

Subsurface geology of Louisiana hazardous waste landfills: A case study

Many hazardous waste sites in the south Louisiana Gulf Coast have been emplaced in sediments of Plio-Pleistocene to Recent age. Because of the fining upward nature of these regressive-transgressive fluvial-deltaic sequences and the purported confining capabilities of the shallow clay layers within them, this area would seem to be ideal for the location of surface waste landfills. However, detailed geologic mapping at a site in southeastern Louisiana documents how the three-dimensional distribution of sediment types and early diagenetic features, both of which were ultimately controlled by depositional history, can increase effective vertical permeability of finegrained sequences. Many bodies of sand that appear to be isolated in standard geotechnical cross sections can be shown to be part of spatially complex three-dimensional distributary networks, with fine-grained sediments representing overbank and backswamp deposits. Some clay layers are actually a composite of thinner clay beds, each subjected to subaerial exposure and the development of secondary porosity related to soil formation. There has been documented leakage of wastes down through the clays, and a recent study indicates that the effective vertical hydraulic conductivity of the clay layers exceeds 10^–5 cm s^–1, or from one to four orders of magnitude higher than values measured on samples from cores of the same sediment. An understanding of the depositional framework, facies architecture, and diagenetic history of geologic materials underlying waste disposal sites in Louisiana is required for rational development of monitoring and remediation plans.     

Municipal solid waste landfill siting by using GIS and analytical hierarchy process (AHP): a case study in Qom city,Iran

Qom is the eighth most populated city in center of Iran, and its population growth rate is among the highest in this country. Th presence of a Great Salt Lake, petroleum potential and tourism attractions in this city sheds light on the importance of how solid waste landfill locations should be disposed, located and managed as an environmental issue. Considering the key parameters in landfill site selection, in this study a series of location analysis have been conducted to locate optimum regions for municipal solid waste disposal, using analytical hierarchy process (AHP) and geographical information system (GIS). The main factors in selecting the suitable location for waste disposal include geomorphology–hydrography, environmental–social factors and design criteria, each of which are subdivided into several categories. Criteria are selected according to the regional condition; therefore, important factors such as distance from sea and forested areas were not considered. In the next step, digital layers are weighted and classified according to the available standards and expert judgment. Then, analytical multi-criteria decision-making algorithms as AHP and weighted linear combination are applied upon existing layers in GIS. The results show that by implementing the AHP method in this region only 7% of the study area has a very good and appropriate condition for landfill location and the field observation confirms them. Finally, considering the environmental effects of landfill, appropriate locations are suggested.     

Environmental geological assessment of a solid waste disposal site: a case study in Sivas, Turkey

The selection of the disposal site is probably the most important step in the development of solid waste management. In site selection, geology plays a determining role. This study evaluates the characteristics of the environment on the basis of the geological, hydrogeological and geo-engineering properties of the solid waste site of the Sivas city, Turkey. The area is underlain by the Oligocene-Miocene rocks which have limited aquifer properties. Thin Quaternary alluvium and soil cover overlie the Oligo-Miocene rocks, which are represented as well graded sand and inorganic silt of low plasticity. The Quaternary alluvium and soil cover are classified as inorganic clays having a low plasticity and the permeability varies from 1.2×10⁻⁶ to 3.11×10⁻⁶ m/s. These values are much higher than 1×10⁻⁸ m/s, which is accepted for waste disposal standards. Seepage waters have a potential to pollute the ground water and the Kızılırmak River, which is 500 m to the southwest of the waste disposal area and because the disposal site is close to the river, the potential for flash flooding poses a high pollution risk. The waste disposal area must be covered by clay layers or an impervious artificial membrane. In addition, seepage must be controlled and removed from the site.     

Simulation on forecast and control for groundwater contamination of hazardous waste landfill

The groundwater flow and solute transport models were established by Visual Modflow, which was used to forecast the transport process of Cr⁶⁺ in groundwater and simulate the effects of three control measures of contaminants transport after percolation solution leakage happened in the impermeable layer of the landfill. The results showed that the contamination plume of Cr⁶⁺ would reach the pool’s boundary in 10 years, and the distance of contamination transport was 1,450 m. However, the contamination plume will not be obviously expanded between 10 and 20 years. While the ground was covered by hardened concrete, the contamination plume would not reach the pool’s boundary in 20 years. When the leakage-proof barrier was set in the bottom of an unconfined aquifer, the concentration of Cr⁶⁺ was higher than that of the leakage-proof barrier unset, but the result was opposite when setting the leakage-proof barrier in the bottom of confined aquifer. The range of the contamination plume was effectively controlled by setting drainage ditches in which water discharge was 2,298.05 m³ d^?1, which produced monitoring wells which are not contaminated in 20 years. In sum, combining ground hardening with drainage ditches could produce the best effect in controlling contaminants diffusion, and meanwhile, the drainage ditches daily discharge was reduced to 1,710.19 m³ d^?1.     

江西九江市城市垃圾卫生填埋场址适宜性评价优选

利用层次分析法对九江市五个候选垃圾场地进行了适宜性评价优选,在很大程度上减少了主观因素影响和定性分析过多的缺点,为九江市重建垃圾填埋场地提供了科学的依据。     

Management and stability analysis of a seashore waste landfill site in Korea

Annual variation in the amount and composition of waste deposited in the Gimpo #2 landfill, the largest landfill around Seoul, Korea, is reviewed, and the stability of the same landfill is analyzed during waste disposal. For the stability analysis, three empirical stability prediction methods, i.e., linear stability, displacement velocity, and curve stability methods, are used to analyze field-measured settlement and horizontal displacement data. The analysis indicated that national waste management policy has greatly influenced the annual variation in the amount and composition of waste deposited in the landfill. Continuous measurement of geotechnical data and the use of stability analysis based on these data are necessary for landfills on seashore clay foundation. Stability of the landfill must be examined with various methods to ensure accurate determination of its stability.     

Geo-engineering problems at Llwyneinion hazardous waste site near Rhosllanerchrugog, North Wales

At Llwyneinion, a clay pit excavated in Carboniferous Bettisfield Formation was utilised for hazardous waste disposal prior to 1972. Approximately 94,000 t of acidic asphaltic sludges and pitches was poured directly into the pit together with 7500 t of spent bentonite containing absorbed oil. Numerous chemical drums were also dumped in the sludge. The unlined acidic asphaltic sludge and pitch lagoon occupies 1.3 ha, ranges up to 10 m deep and is underlain by fissured strata and extensive mineworkings including three shafts. The heterogeneous asphalt waste has developed a semi-solid asphalt layer at the base but mostly remains in a viscous and mobile condition. A surface layer of rainwater less than 0.4 m deep covers the waste. Surprisingly, detailed hydrogeological studies of the area surrounding the acidic asphaltic sludge and pitch lagoon failed to disclose any significant contamination of aquifers, however regular monitoring of water conditions is performed as a safeguarding measure. Various remediation strategies have been assessed and rejected. They fall into two main categories; those involving on site treatment of the acidic asphaltic sludges and pitches and encapsulation and those aimed at removal of the material to facilities elsewhere in the country. Investigations and deliberations continue in order to determine the optimum way forward.     

Environmental problems associated with the development and operation of a lined and unlined landfill site: a case study demonstrating two landfill sites in Patra,Greece

The present work demonstrates the environmental problems associated with the development and operation of a lined and unlined landfill site, both used for municipal solid waste landfilling, that are situated next to the city of Patra, Greece. Findings from a detailed site investigation as well calculations on hydrologic evaluation of landfill’s performance and measurements on leachate composition proved that the lined landfill site is more secure and environmental friendly compared with the unlined landfill site. Even though, until today, there is no evidence from near boreholes for severe contamination problems generated by any of the two landfills, in the forthcoming future several environmental problems are expected to occur from the unlined site. In addition the prevailing hydrogeotechnical conditions indicated that the unlined site is a potential source of contamination; hence extra remedial measures should be received by the local authorities to prevent severe contamination in soil and groundwater.     

Engineering geological aspects of replacing a solid waste disposal site with a sanitary landfill

The current solid waste disposal site in the Mamak district of Ankara is being engulfed by the growing city. All varieties of solid wastes, including medical wastes, are stored at the present site in an irregular manner. Topographical and geological conditions at Mamak waste site are favorable for constructing a sanitary landfill. Located at the edge of a topographical depression, the site is underlain by the natural hydraulic barriers such as clay and metagreywacke. The terrestrial clay has a permeability of 10⁻⁷ to 10⁻⁸ cm/s and low to moderate values of CEC. The proposed sanitary landfill to replace the present solid waste site has a capacity of storing solid waste over 50 years. The details of base liner, final cover, toe embankment, and drainage of leachate and gas are presented in the paper.     

Selection of hazardous waste dumpsites based on parameters effecting soil adsorption capacity – a case study

A careful selection of waste dumpsites, particularly hazardous ones, is very important for sustainable water resources management. Several laboratory experiments were carried out on the field samples to study adsorption capacity using p-dichlorobenzene (a solvent used in various industrial processes) as the test contaminant. The effect of parameters such as organic matter, clay, and iron and aluminium oxides, which are known to influence the soil adsorption capacity, are studied in the present work. Several soil samples from the Patancheru Industrial Area (Hyderabad, India) were collected and characterized. Only three soils, which had a comparatively high percentage of organic matter, clay, iron and aluminium oxide contents were used for the adsorption studies. The results clearly indicated a decrease in the adsorption capacity of the soils by as much as 75% when organic matter was removed. The other parameters such as clay and iron and aluminium oxides also play an important role in adsorption (57 and 39.8% reduction respectively). It was observed that out of the selected factors organic matter in the soils has the maximum effect regarding the adsorption of p-dichlorobenzene. Since the selected soils contain comparatively more organic matter, clay and iron and aluminium oxides in the selected industrial area, these can be used as sites for dumping hazardous waste, which can be further treated by methods like bioremediation.     

Method of leakage study at the karst dam site. A case study: Khersan 3 Dam,Iran

The excellent topographic condition of the limestone canyons for dam construction may be rejected if they are karstified. Karst features cause the reservoir not to be impermeable enough to permit the water to fill it and leakage occurs and often increases with time. Moreover, karst features may involve the stability of the dam itself. A few operated dam sites at the Zagros Zone encountered a leakage problem. Furthermore, more than 30 dams are presently under study for construction in the Zagros Zone. Karst conditions and leakage potential were investigated at an under-study site (Khersan 3 Dam) for assessing the general methodology for the study of leakage potentials. Conventional methods for studying karst features, geological mapping, geomorphology and extensive borings were applied before the dam was constructed. These methods are not efficient enough to precisely reveal the karst structure, especially hidden and paleokarst, nor the hydrological behaviour of the karst structure in different settings of groundwater flow. Based on the present case study and previous applied approaches by other authors, this paper introduces a methodology by means of karst structure and functioning approaches at local and regional scales that cover the conventional methods and overcome their shortages. The proposed methodology should be applied before construction of a dam and should include three steps (a) recognition of geological and hydrogeological settings, (b) delineation and functioning of the karst system related to the future reservoir, and (c) assessment of the leakage potentials. Following this methodology, the most probable leakage zone(s) and path(s) at the dam site can be highlighted.     

Genesis of Tertiary Magnetite–Apatite Deposits,Southeast of Zanjan,Iran

Magnetite–apatite deposits in the Alborz volcano–plutonic belt, southeast Zanjan, in Iran, have blade, lenzoid, and vein forms, which extend in an E‐W direction. There are many magnetite–apatite veins and veinlets in this region, and some of them are economically important, such as Zaker, Morvarid, Sorkheh–Dizaj, and Aliabad. The sizes of the vein orebodies vary between 2 and 16 m in width, 10–100 m in length, and 5–40 m in depth. Microscopic examination of thin sections and polishes indicate that they are composed of magnetite and apatite, with minor amounts of goethite, hematite, actinolite, quartz, muscovite–illite, talc, dolomite, and calcite. The geochemistry and mineralogy of the granitic host rock reveals that it is calc‐alkaline and I‐type. Field observations, mineral paragenesis, the composition of the orebodies, and the composition of the fluid inclusions in the apatite minerals with low salinity (less than 20 wt.% NaCl equivalent) indicate that these magnetite veins were hydrothermally generated at about 200–430°C and are not related to silica–iron oxide immiscibility, as are the major Precambrian magnetite deposits in central Iran.     

Investigating remote sensing indices to monitor drought impacts on a local scale (case study: Fars province,Iran)

As drought occurs in different climates, assessment of drought impacts on parameters such as vegetation cover is of utmost importance. Satellite remote sensing images with various spectral and spatial resolutions represent information about different land covers such as vegetation cover. Hence, the purpose of this study was to investigate the performance of satellite vegetation indices to monitor the agricultural drought on a local scale. In this regard, satellite images including Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) data were used to evaluate vegetation cover and their gradual changes effects on agricultural drought. Fars province in Iran with relatively low precipitation values was selected as the study area. Modified Perpendicular Drought Index (MPDI), MPDI1, Vegetation Condition Index (VCI), Normalized Difference Vegetation Index Anomalies (NDVIA), and Standardized Vegetation Index (SVI), were evaluated to select the remote sensing based index with the best performance in drought monitoring. The performance of such indices were investigated during 13 years (2000–2013) for MODIS and 29 years (1985–2013) for AVHRR. To assess the efficiency of the satellite indices in drought investigation, Standardized Precipitation Index (SPI) data of five selected stations were used for 3, 6, and 9 month periods on August. The results showed that NDVI-based vegetation indices had the highest correlation with SPI in cold climate and long-term timescale (6 and 9 month). The highest correlation values between remote sensing based indices and SPI were acquired, respectively, in 9-month and 6-month time-scales, with the values of 43.5% and 40%. Moreover, VCI showed the highest capability for agricultural drought investigating in different climate regions of the study area. Overall, the results proved that NDVI-based indices can be used for drought monitoring and assessment in a long-term timescale on a local time-scale.

     

Site selection for hazardous wastes: A case study from the GAP area, Turkey

The increase in the popularity of using environmental design criteria in town and country planning has brought about the need to fully identify the principles to determine the best location of hazardous wastes to be landfilled. This environmental management issue has received considerable attention because of its applications in urban and rural infrastructure planning, industrial development planning as well as health, housing, transportation and agricultural schemes. This paper explains a method to determine how to locate suitable sites for hazardous waste landfilling area by using the site screening study. It demonstrates how the criteria such as geology, topography, land use, climate, earthquake and other related factors can be introduced into the overlayer technique to determine the suitable site selection in a region. The research was undertaken in the Southeastern Anatolia Project (known as GAP in Turkey) region where identifying the land resources is crucial for agricultural and water management purposes. The paper also explains the validity of the method employed on the site selection process for hazardous wastes. The introduced method may enable more accurate design procedure for planning in environmental management in future.     

Ground magnetic survey of a municipal solid waste landfill: pilot study in Argentina

This paper shows the results of a ground magnetic survey carried out to study solid waste landfills. The area located southward of Gualeguaychú town was chosen as a pilot case. This zone was selected considering the available knowledge about the cessation of operations, and the interest of the local authorities in verifying the existence of anomalies indicative of possible dangerous pollutants. The total magnetic field was measured along six profiles, and the corresponding anomalies were calculated. The profiles were modelled in 2.5 D, and along them Eulers deconvolution was used to estimate the depth to the sources. The first and the second derivatives of the residual magnetic field were calculated, in order to sharpen the anomalies. Our interpretation suggests that the characteristics of the modelled bodies and the magnitudes of the detected anomalies do not indicate the presence of drums in the sanitary infill.