Search

The disposal of industrial and sewage water is a problem of increasing importance throughout the world. In India, and most of the developing countries untreated sewage and industrial wastes are discharged on land or into the running water streams which is used for irrigating crops. These wastes often contain high amount of trace elements which may accumulate in soils in excessive quantities on long term use and enter the food chain through absorption by the plants. Among the trace metals, Cd has received the greater attention because of its easy absorption and accumulation in plants and animals to levels toxic for their health. The objective of this study conducted in three industrially different cities viz., Ludhiana, Jalandhar and Malerkotla was to monitor the extent of Cd accumulation in soils and plants receiving untreated sewage water. Plant and soil samples were collected from sewage and tubewell irrigated areas. Soil samples were analysed for texture, pH, EC, organic carbon (OC), CaCO3, bioavailable DTPA–Cd and plant samples were analysed for total Cd. In sewage irrigated soils, the mean values of pH were lower but organic carbon and electrical conductivity were generally higher both in surface and sub-surface layers of all the three cities as compared to tubewell irrigated soils. The mean DTPA- extractable Cd in sewage irrigated soil was 6.3- and 4.36-fold in Ludhiana, 3.38- and 1.71-fold in Jalandhar and 3.35- and 6.67-fold in Malerkotla in 0–15 and 15–30 cm soil depth, respectively, compared with the values in tubewell irrigated soils. The accumulation of DTPA–Cd in sewage irrigated soils was restricted to 30 cm depth after which the values were generally close to values in tubewell irrigated soils. Soil pH, OC, CaCO3, clay and silt collectively accounted for 37.1%, 65.1% and 53.9% DTPA-extractable bioavailable Cd in soils of Ludhiana, Jalandhar and Malerkotla, respectively. Lower R2 values in Ludhiana suggest that factors other than the ones mentioned may be affecting Cd availability. At all sites plants receiving sewage irrigation had elevated levels of Cd as compared to the plants receiving tubewell irrigation. The mean Cd content of sewage irrigated plants irrespective of the city was 5.96 μg g − 1 dry matter as compared to 0.98 μg g − 1 dry matter in tubewell irrigated plants. The results suggest that the intake of Cd obtained from consumption of crops grown on sewage irrigated soils would be much higher than the tolerable limits set by WHO and may, therefore, prove potentially toxic leading to various health ailments to humans and animals. [ABSTRACT FROM AUTHOR]

Land application of wastes generated from concentrated animal feeding operations may result in accumulation of tetracyclines (TCs) and metals in agricultural soils. Adsorption of TCs and metals on soil minerals strongly affects their mobility. This study was conducted to evaluate the interaction between tetracycline (TC) and Cu(II) with regard to their adsorption and cosorption on montmorillonite as affected by solution pH. When solution pH was below 6.5, the presence of TC increased Cu(II) adsorption on montmorillonite, which could be due to increasing Cu(II) adsorption via the TC bridge, or due to the stronger affinity of TC-Cu(II) complex to the mineral than Cu2+ ion itself. Zeta potential of the montmorillonite significantly decreased after the adsorption of TC, suggesting a strong interaction between TC and montmorillonite. Addition of Cu(II) ions increased TC adsorption on the mineral in a wide range of pH. The experimental data were well fit with the weighted sum model. The complexes of TC and Cu(II) (CuH2L2+, CuHL+ and CuL) had higher sorption coefficients (Kd) than that of the corresponding TC species (H3L+, H2L, and HL-). Increasing adsorption of TC and Cu(II) on montmorillonite as they coexist in the normal pH environment may thus reduce their mobility. [ABSTRACT FROM AUTHOR]

The identification of uncontrolled landfills is a central environmental problem in all developed and developing countries, where several illegal waste deposits exist as a result of rapid industrial growth over the past century. Remote sensing can potentially provide crucial information for the identification of contaminated sites, but surprisingly there is a marked lack of rigorously validated approaches. In this paper we introduce and validate a method that uses remotely sensed information and a geographic information system (GIS) to identify unknown landfills over large areas. The method is applied to a study area located in NE Italy (part of the Venice lagoon watershed) using IKONOS satellite data. Soil contamination effects on the radiometric properties of vegetation, calibrated using spectral signatures of stressed vegetation from known illegal landfill sites, were used to define numerous candidate sites that are most likely to host waste materials. Distributed geographical information, such as the position of the road network, the population density, and historical aerial photographs, have then been used to select the most likely contaminated sites among the candidates identified through remote sensing. The importance of the integration of GIS and remote sensing is highlighted and represents a key instrument for environmental management and for the spatially distributed characterization of possible uncontrolled landfill sites. [ABSTRACT FROM AUTHOR]

Remediation for contaminated farm soil had become an important task in Taiwan for the authorities because many farms had been contaminated with heavy metals due to illegal discharges of industrial wastewater. A comprehensive and effective remediation methodology for heavy metal-contaminated farm soil was presented in Taiwan, which integrated assessment of soil contamination and environmental characteristics, remediation technology, and performance assessment. Turnover and attenuation method was chosen and applied in this study based on assessment criteria of social, technological, economical, and environmental feasibilities. However, there were some difficulties needed to be solved when turnover and attenuation method was applied because of great variation of environmental characteristics in Taiwan. A sustainable management framework based on Managing for Results method was therefore developed for guiding the accomplishment of the remediation tasks. Three contaminated sites had been successfully completed for the remediation tasks in this study by using the proposed integral methodology. The distribution of heavy metal concentrations in soils and environmental characteristics had been predicted using the proposed rule for determining adequate number and locations of sampling points and used to calculate the excavation depth for each area. The results of performance measurements showed that the farm lands had recovered their agricultural utility to meet the landowners' request, heavy metal concentrations in the soils had been reduced with proper attenuation ratio, remediation cost had been controlled in the range of the budget, and heavy metal concentrations in the soils and crops after remediation can meet the regulatory limits. The comprehensive and effective remediation methodology could be employed to assure the effectiveness and efficiency of the remediation tasks based on the principles of sustainable development, as observed from the analytical results of the three contaminated cases. [ABSTRACT FROM AUTHOR]

Surface soil samples were collected from 52 sites around Guanting Reservoir in Beijing, China, and contents of ‘total’ metals (Cu, Zn, Pb, Cd, As, Ni and Cr) were determined. The results indicate that the degree of heavy metal pollution in the soils declines in the order of Cd>Cr>Zn>As>Cu>Ni>Pb. Based on the results of a combination of multivariate statistics and geostatiscal analyses, it was concluded that land application of phosphate fertilizer, wastewater and sludge were the primary sources of Cd and Zn in soils. Whereas As, Cu, Cr and Ni in some soils were due to natural rock weathering. The sources of Pb in soils only partially originated from land application of phosphate fertilizer, but mainly from vehicle exhaust. The greatest concentrations of all metals, except for Pb, were found in Huailai County and the towns of Yanghedaqiao and Guanting. [Copyright &y& Elsevier]

Contamination with heavy metals and microbes of roots of Valerian (Valeriana officinalis L.) grown in either unamended soil (US) or sewage sludge-amended soil (SSAS) were studied in two seasons in the UK. The concentrations of heavy metals found in the washed roots from SSAS were greater than the concentrations found in roots from the US plots by 480, 2800, 215, 1900, and 82% (in 2002) and 234,446, 187,426, and 450% (in 2004) for cadmium, chromium, copper, lead, and zinc, respectively. Drying reduced the levels of coliforms, and washing treatments also tended to reduce the levels of microorganisms (Clostridia, molds, Bacillus sp.) detected on dried roots. [ABSTRACT FROM AUTHOR]

Linear alkylbenzene sulphonates (LASs) are anionic surfactants commonly used in commercial detergents. A potential risk associated with the recycling of sewage waste materials is the presence of LASs and their primary degradation products, which could accumulate in sludge, especially during anaerobic processing. The long‐term accumulation of these contaminants in soils and especially the potential disturbance of soil functions need to be studied in more detail. In our study, the influence of the amendment added to an agricultural soil with different organic wastes containing LASs on organic matter content and nitrogen (N) content evolution and mineralization was studied in field conditions. A completely randomized 3×3 factorial arrangement, representing two sewage sludge types (composted and uncomposted) and three levels of LAS presence (0, 15, and 30 g/m2) in treated soils, was established using field plots (7×2 m); the results are compared with untreated plots. Statistical models based on covariance analysis were used to understand the dynamics of and the main factors influencing carbon (C) and N mineralization in sewage sludge amended–soils in the presence of LAS. LAS seemed to alter nitrogen mineralization, especially the nitrate dynamics. [ABSTRACT FROM AUTHOR]

Lead removal from water and contaminated soils was investigated using biosurfactant, anionic, and nonionic surfactants in continuously stirred batch reactors. Lead-contaminated water up to 100 mg/L and clay soil up to 3,000 mg/kg were used in this investigation. The surfactant concentration up to 10 critical micelle concentration was used. The speciation of lead into the micelles was quantified and the lead removal efficiency depended on the level of contamination, surfactant type, and concentration. Of the surfactants used, biosurfactant (produced from used vegetable oil) had the best removal efficiency (75%) at a lead contamination of 100 mg/L in water at pH of over 12. The Fourier-transformed infrared spectroscopy study showed that the carboxyl group in the biosurfactant was effective in removing the lead from the solution. Langmuir and Freundlich relationships were used to represent the micelle partitioning of lead in the surfactant solutions. Desorption of lead from contaminated kaolinite clay was represented using linear isotherms. The biosurfactant solution had a higher micelle partitioning for the lead from contaminated water and desorbing the lead from the contaminated soil compared to the other chemical surfactants. [ABSTRACT FROM AUTHOR]

Vertical distributions of COS and CS2 were measured at a meteorological tower in Beijing City. The mixing ratios of COS and CS2 are in the range of 371-1681 pptv and 246-1222 pptv, respectively. The significant high mixing ratios of the two compounds at ground level and distinct vertical distributions indicated the existence of strong anthropogenic sources of COS and CS2 in Beijing City. Domestic stoves and central heaters are important sources of COS during winter season Cesspools may play significant role on COS over whole seasons. Chemical productions may be responsible for the observed high mixing ratios of CS2 in Beijing City. [ABSTRACT FROM AUTHOR]

Describes the chemical mechanisms governing transport and reduction of hexavalent chromium (Cr) in soils of a contaminated industrial waste landfill. Characterization of the metal pollution distribution in the groundwater of the industrial site; Determination of the bearing phases of Cr contamination in soil samples; Identification of the mechanisms responsible for chromium immobilization in soils.

Provides an overview of the history of the Love Canal, which began in the 1880s as a failed attempt to connect Lake Ontario and Lake Erie near Niagara Falls. Acquisition of the canal by the Hooker Chemical Company in 1942; Number of tons of chemical waste disposed by the chemical company in the area between 1942 and 1975; Contribution of the environmental problem to the emergence of environmental activism.