Waste Dump Area Research Articles

Microbial Consortia Preparation for Amylase, Protease, Gelatinase and Lipase Production from Isolates Obtained from Organic Kitchen Waste

Households, restaurants, canteens, and hotel wastes constitute kitchen waste. Every day our growing cities generate more and more waste, which is overloading our municipal systems. The main aim of the present work was to prepare a microbial consortium that can effectively and rapidly bring about the degradation of kitchen wastes that can be used in agricultural soils. More than 100 different bacterial isolates were obtained from various kitchen waste dumping areas. The bacterial isolates were studied to produce enzymes like amylase, gelatinase, lipase, and protease on respective media plates. The best 20 isolates were subjected to enzyme quantification. The isolates showing maximum production for all four enzymes were selected for consortia preparation. The consortia of isolates were prepared by permutation combinations. Amongst all consortia prepared consortium No. 7 showed maximum enzymatic potential. The bacterial isolates in the best consortium (No. 7) were further characterized and identified as KW104 Serratia marcescens, KW37 Micrococcus luteus, KW128 Brevindimonas mediterranea, KW91 Bacillus tequilensis, and KW97 Exiguobacterium mexicanum. This consortium showed rapid degradation of waste as compared to others in 15 days duration of time showing good potential for compost formation when applied to plant growth.

MFE-ResNet: A new extraction framework for land cover characterization in mining areas

Obtaining accurate information about land cover is a critical aspect of environmental monitoring in mining areas. However, the land cover in these areas is often complex and poses a challenge for analysis compared to other landscapes. This results in the difficulty of acquiring effective features and an unbalanced proportion of available training samples. We introduce a new approach to obtaining effective image features and enhancing the extraction of open-pit (OP) and waste-dump area (WDA) by using a mining feature-enhanced ResNet (MFE-ResNet). Our framework utilizes image objects as the basic units of high spatial resolution images (HSRIs) to better incorporate spatial and geometric information. The MFE-ResNet is an improvement of the ResNet18 architecture, forming a 26-layer network, and reducing the computational complexity by changing the convolutional kernel size. A squeeze-and-excitation (SE) module is also introduced to form an SE-residual structure to improve the network’s ability to perceive the detailed mining area features. To alleviate the sample imbalance problem, a switchable normalization (SN) layer is applied to optimize the internal network structure. In addition, focal loss is introduced in the training process. We build an evaluation system that considers both the number of objects and their area. Compared with other six deep learning methods, our MFE-ResNet achieves the best overall accuracy in both large and small study areas. Specifically, MFE-ResNet obtained F values (F) of 87.73% and 97.28%, and quality (Q) of 81.37% and 95.18% in OP extraction. The F of WDA extraction improved by 0.99% and 2.13%, and the Q improved by 0.98% and 9.56% compared to the second-ranked model. We show that our framework exhibits promising performance in monitoring mining areas.

Stability Evaluation of Medium Soft Soil Pile Slope Based on Limit Equilibrium Method and Finite Element Method

The stability of an open-pit slope is an extremely important factor related to the safe production of an open-pit mine. It is the first safety technical problem encountered and should be solved in the process of mine design and production. By the means of an engineering geology and hydrogeological investigation of the waste dump area of the Nayuan open-pit coal mine and numerical simulation research, this paper analyzes and studies the slope stability of the stope and waste dump of the Nayuan open-pit coal mine in detail and puts forward measures such as slope prevention and automatic monitoring to achieve the goal of protecting the slope of the stope and waste dump and the surrounding environment. The main research results are as follows: (1) The geotechnical physical and mechanical indexes of stope and waste dump are collected and analyzed, and the geotechnical mechanical indexes in this report were determined, which basically meet the requirements of slope stability analysis. (2) The limit equilibrium method and finite element method were used to analyze and evaluate the current slope stability of the Nayuan open-pit coal mine. It was concluded that the foundation of the waste dump is basically stable, and the potential landslide modes of the slope are arc-shaped sliding surface and arc-shaped straight-line sliding surface. The numerical simulation and checking results showed that the current stope and waste dump slope are stable. (3) According to the analysis and evaluation results of slope stability, feasible slope prevention measures are put forward. The research results are of great significance to the safety of important facilities in open-pit mines and provide a basis for the design and safety implementation of open-pit slope engineering.

SETLING POND DESIGN CONSIDERING SEDIMENTATION DEPOSIT RATES AT ARAFAH AREA AND WASTE DUMP OF PT. GAG NIKEL MINING FRONT, RAJA AMPAT REGENCY, WEST PAPUA PROVINCE

It is very important to know the design of the mine drainage system where to know the maximum rainfall each year, the extent of the catchment area, rainwater runoff discharge, sedimentation speed, open channel dimensions, and sedimentation pond dimensions. The problem in this research is, how much the catchment area is, the limited rainfall owned by the company, sedimentation speed, sedimentation pond dimensions, and open channels. So that the results of the above problems are obtained, namely the extent of the Arafah rain catchment area 103810,009 m2, waste dumps I 256.901 m2, and waste dump II 327172.506 m2. Runoff discharge at the area of 0.763 m3 / second, waste dump I 1,889 m3 / second, waste dump II 2,405 m3 / second. Sedimentation speed compressed 0,000365 m / s, open channel dimensions (neural area) I = 0.4 m, b = 0.45 m, t = 1.2 m, d = 0.7 m, h = 0.4 m. Waste dump area 1. I = 0.5 m, b = 0.63, t = 1.65 m, d = 1 m, h = 0.5 m. Waste dump area II. S = 600, I = 0.6 m, b = 0.7 m, t = 1.8 m, d = 1.1 m, h = 0.6 m. Dimension of Arafah settling ponds, 2091.063974 m2, waste dump I, 5174, 822463 m2, waste dump II, 6590, 295552 m2. For sump dimensions with a depth of 2 meters, a length of 56,42 meters, and a width of 26,40 meters with a volume of 2450,444 m

Distribution, source and ecological risk assessment of polycyclic aromatic hydrocarbons in groundwater in a coal mining area, China

The impact of exposure to polycyclic aromatic hydrocarbons (PAHs) on the ecological environment has aroused widespread concern in coal mining areas. Coal mining and solid waste accumulation are among the main reasons for the widespread occurrence of PAHs in groundwater in mining areas. In this study, the PAH content in groundwater in a coal mining area in northern Anhui, China, was determined via gas chromatography–mass spectrometry (GC–MS). The seasonal variation, composition, spatial distribution and sources of PAHs were analyzed, and their potential ecological risks were evaluated. The concentration of ∑PAHs in groundwater ranged from 15.04 to 449.13 ng/L, mainly including 2- and 3-ring PAHs. There were obvious differences in the PAH distribution in groundwater, and higher PAH concentrations were detected in groundwater near industrial parks and solid waste dumping areas. Diagnostic ratio analysis indicated that the PAHs mainly originate from the combustion of coal, biomass and petroleum. The positive matrix factorization (PMF) results revealed that coal and biomass combustion, traffic emissions, coking emissions and oil leakage contributed 46.59%, 20.06%, 18.70% and 14.65%, respectively, to the detected PAHs. The ecological risk assessment results indicated that this area experienced a moderate ecological risk, and the mean ecological risk values during the wet season were lower than those during the dry season.

SAFE MANAGEMENT OF E-WASTE DISPOSAL TO PREVENT HARMFUL EFFECTS ON HUMAN HEALTH AND THE ENVIRONMENT

Using electronic devices is a common thing nowadays. Moreover, in the COVID-19 pandemic, all activities must be done from home. Learning, working, and leisure activities are done from home by gadgets. Therefore, electronic device demands are getting higher. E-waste disposal must be a concern for all electronic device users. Lack of awareness on proper management for e-waste disposal may cause harmful effects on human health, plants, soils, and the environment. The effects are increasing the risks of cancers, soil, and environmental pollution. This paper aims to describe the safe management of e-commerce-waste disposal to prevent harmful effects on human health and the environment. Databases from Science Direct, PubMed, and Google Scholar were used. The keywords were disposal AND environment AND e-waste AND health AND management. There were 2170 journals at the beginning. After screening by the title, abstract, and full text, there were 35 journals. Inclusion criteria were full text available, review, and research. Exclusion criteria are opinion and commentary. Reverse logistics is a way to dispose of e-waste by increasing the economic value of the waste. Another alternative to e-waste management is making art and craft from e-waste. Conclusion: Reverse logistics must be taught to people to save the planet from the harmful effects of the unwise management of e-waste disposal. Art and craft from e-waste can be done to increase economic value and reduce hazards to health and the environment. Soil assessment of heavy metal concentration surrounding the waste dump area must be done regularly to prevent bioaccumulation.

Los pepenadores y el tiradero de basura de la Sierra de Guadalupe (Tultitlán, México). Estudio de la Geografía de las Emociones centrado en el asco

From the perspective of the Geography of Emotions, we study the case of the solid waste dump area of Sierra de Guadalupe, in Tultitlan, State of Mexico; in particular we focus on disgust and its relation to the garbage dump dynamics and the lives of garbage collectors. The emotion of disgust is reviewed as well as its main explanations from biology and culture. We briefly present the problem of garbage, to continue with the living conditions of a group of people who live and/or work in the vicinity of the dump. Finally, the relationship between garbage, disgust, and territory is explored. We find that this emotion affects the configuration of territory, and that garbage and disgust seem to go together for some, while for others, garbage is a source of employment and life.

Environmental investigation of pollutants in coal mine operation and waste dump area monitored in Ordos Region, China.

The increasingly severe emissions of greenhouse and poisonous gases from environmentally unsafe stockpiled coal mine waste dumps have urged people from the academia as well as the industry to focus on environmental impact assessment. In this study, one-year air pollutant monitoring was conducted at the Qipanjing coalfield in Inner Mongolia of China for determining the distribution pattern statue of pollutant exposure and its main driving factors. We used FTIR spectroscopy to measure the inorganic compounds in particulate matter with a diameter of less than 2.5 μm. The spatial and temporal distribution characteristics of leading pollutants, including PM2.5, PM10, SO2, NO2, O3 and CO were analyzed. Firstly, the research showed that the temporal and spatial distribution of pollutants in the coal mine waste area is non-homogeneous. Secondly, some meteorological parameters, such as wind speed, relative humidity, temperature, and rainfall, were found to have significant effects on air pollutant distribution. Stable atmospheric conditions were unfavorable for the diffusion of pollutants and prolong the pollution process. Finally, in the vicinity of coalfields, SO2 and NO2 are present in high concentrations in air. Primary reasons for such high values are coal mining-related activities and active mine fires. This study will help to offer valuable and detailed information for understanding and interpreting the pollution source.

Trace gas emissions from municipal solid waste landfills: A review

Trace gas emissions from municipal solid waste (MSW) landfills have received increasing attention in recent years. This paper reviews literature published between 1983 and 2019, focusing on (i) the origin and fate of trace gas in MSW landfills, (ii) sampling and analytical techniques, (iii) quantitative emission measurement techniques, (iv) concentration and surface emission rates of common trace compounds at different landfill units and (v) the environmental and health concerns associated with trace gas emissions from MSW landfills. Trace gases can be produced from waste degradation, direct volatilisation of chemicals in waste products or from conversions/reactions between other compounds. Different chemical groups dominate the different waste decomposition stages. In general, organic sulphur compounds and oxygenated compounds are connected with fresh waste, while abundant hydrogen sulphide, aromatics and aliphatic hydrocarbons are usually found during the methane fermentation stage. Selection of different sampling, analytical and emission rate measurement techniques might generate different results when quantifying trace gas emission from landfills, and validation tests are needed to evaluate the reliability of current methods. The concentrations of trace gases and their surface emission rates vary largely from site to site, and fresh waste dumping areas and uncovered waste surfaces are the most important fugitive emission sources. The adverse effects of trace gas emission are not fully understood, and more emission data are required in future studies to assess quantitatively their environmental impacts as well as health risks.

Comparative growth potential of thermophilic amylolytic Bacillus sp. on unconventional media food wastes and its industrial application.

Amylases take part with vital role in industries such as food, fermentation; starch processing, textile and paper etc. Increasing amylases demand, high nutrient expenditure and environmental pollution have forced to utilize agro-industrial residues as a low-cost feedstock for enzyme production. In present study, three soil samples were collected from agro-industrial waste dumping areas in District Faisalabad. Ten thermophilic bacterial isolates were separated at 55 °C on the basis of colonial morphology, three isolates (F6, F11, F17) showed prominent zone of clearance applying iodine test on starch agar plates. Bacterial isolate F-11 showed highest amylase activity with DNS method and molecularly identified through 16S RNA sequencing as Bacillus sp. with Accession number MH917294. Four unconventional food wastes (banana, lemon, mango and potato) pretreated with 0.8% sulphuric acid concentrations taking 1000 g/L weight released the highest sugars contents and phenolic components. Maximum amylase activity i.e. 29.23 mg/ml was achieved in mango waste at, 40 °C, with pH 6.0 and 0.17% nitrogenous source adding 8% inoculum size (2 days old) using Response Surface Methodology (RSM) for optimization. Crude amylase confirmed its efficiency in starch hydrolysis that suggested it as potential candidate for application in starch industries.

Impact of phytoremediation and bioaugmentation on microbial community in oil shale chemical industry solid waste

Field and laboratory experiments were carried out in order to estimate the suitability ofphytoremediation and bioaugmentation for oil shale chemical industry solid waste (semicoke) dump area remediation as well as influence of plants and laboratory selecteddegradative bacterial strains on the microbial communities in semi-coke, Field test plots (each50 m2) were established at semi-coke depository in July 200 I and samples for microbiologicaland chemical analysis were collected in October 2002 and 2003, Microbial communities insemi-coke were · analysed using both culture-based and molecular methods, Changes inmicrobial community structure and activity occurred in semi-coke as a result ofphytoremediation and bioaugmentation, Phytoremediation increased the number of oildegrading bacteria and diversity of microbial community in semi-coke as well as microbialbiomass. A comparison of 16S rRNA gene-based DGGE fingerprints of semi-coke samplesusing multivariate analysis showed variation between the bacterial community profiles fromdifferent treatments. Degradation rates of pollutants did not differ significantly between plotswith vegetation except for sod, showing negligible effect of soil amendment typeonbiodegradation activity. Our results indicate that increased biodegradation activity was due toproliferation of specific microbial groups, changes in taxonomic and metabolic diversity ofbacterial community and shifts in the structure of catabolic genes, Based on our findings weconclude that phytoremediation and bioaugmentation could be considered as an alternativemanagement option for remediation of oil shale solid waste.

Effects of electronic waste on cytogenetic and physiological changes in snakehead fish (Channa striata).

The objectives of this study were to investigate cadmium (Cd), chromium (Cr), and lead (Pb) concentrations in water and sediment as well as the muscle, gill, and liver of snakehead fish (Channa striata) and to reveal chromosomal aberrations, changes in serum biochemical parameters, and histopathological alterations of fish from a reservoir near an electronic waste dumping area. Cd, Cr, and Pb concentrations were determined using inductively coupled plasma optical emission spectrometry. Chromosomal aberrations were studied in kidney cells using a conventional technique. The biochemical parameters were measured using an automated analyzer, and histopathological photographs were obtained using a transmission electron microscope. The results showed that heavy-metal concentrations in water and sediment did not exceed the standards, whereas Cd and Pb concentrations in the gill and liver exceeded the standards. The accumulation pattern of heavy metals in organ tissues was exhibited according to the following order: gill > liver > muscle. Five types of chromosomal aberrations were a centromere gap, single chromatid break, deletion, single chromatid gap, and fragmentation. The average percentages of chromosomal aberrations in polluted and reference C. striata were 4.60% and 1.00%, respectively. The statistical analyses of chromosomal aberration and biochemical parameters indicated that total protein, aspartate aminotransferase, and alanine aminotransferase significantly differed between the polluted and reference C. striata (p < 0.05). The liver histopathological alterations revealed atypical cellular structures, such as vacuolar appearance, nucleus degeneration, rough endoplasmic reticulum disintegration, abnormal cytoplasmic mitochondria, and deposition of heavy metals. Heavy-metal contaminations from electronic waste dumping areas affect fish in terms of chromosomal aberration, serum biochemistry, and histopathology.

Remote detection of ragweed (ambrosia artemisiifolia l.)

The paper presents the contemporary findings of remote sensing regarding the control of common ragweed on agricultural land. The two-year research was performed in co-operation with the company Ciklonzacija Ltd., Serbia. The remote sensing process starts with the collection of images captured by several types of cameras equipped with special filters. Images are obtained by modified cameras mounted on helicopters, drones, and airplanes. Next, a special software is used to produce maps based on the obtained images that show the level of weed spread on agricultural land, illegal waste dumping areas, and other uncultivated areas, i.e. the areas that are potential sources of ragweed spread. The maps have a considerable economic benefit when mapping agricultural, wood, and other areas. Moreover, they reduce the use of human resources, and increase the capacity of data acquisition as well as the accuracy of the model of weed spread and its control.

Temporal and spatial changes of land use and landscape in a coal mining area in Xilingol grassland

Coal mining, particularly surface mining, inevitably disturbs land. According to Landsat images acquired over Xilingol grassland in 2005, 2009 and 2015, land uses were divided into seven classes, i. e., open stope, stripping area, waste-dump area, mine industrial area, farmland, urban area and the original landscape (grassland), using supervised classification and human-computer interactive interpretation. The overall classification accuracies were 97.72 %, 98.43 % and 96.73 %, respectively; the Kappa coefficients were 0.95, 0.97 and 0.95, respectively. Analysis on LUCC (Land Use and Cover Change) showed that surface coal mining disturbed grassland ecosystem: grassland decreased by 8661.15 hm2 in 2005-2015. The area and proportion of mining operation areas (open stope, stripping area, waste-dump area, mine industrial field) increased, but those of grassland decreased continuously. Transfer matrix of land use changes showed that waste-dump had the largest impacts in mining disturbance, and that effective reclamation of waste-dump areas would mitigate eco-environment destruction, as would be of great significance to protect fragile grassland eco-system. Six landscape index showed that landscape fragmentation increased, and the influences of human activity on landscape was mainly reflected in the expansion of mining area and urban area. Remote sensing monitoring of coal surface mining in grassland would accurately demonstrate the dynamics and trend of LUCC, providing scientific supports for ecological reconstruction in surface mining area.

A Comparative Study of Municipal Solid Waste Management Status for Three Major Towns of Upper Assam-India

Waste is a major problem for the countries and cities of developing country like India. This present study is carried out to understand the present scenario of waste management status of three major towns of Assam state namely Jorhat, Tezpur and Dibrugarh. A comparative analysis is carried out on the basis of municipal solid waste generation in these three prominent municipalities of Upper Assam. During the present study it is estimated that Tezpur town produces around 28 MT of waste, Jorhat Town produces 35 MT of waste and Dibrugarh Town produces 75 MT of waste respectively. All the three Municipalities are facing problem for disposal of waste as the open dumping ground is affecting the people and environment around the site. Dibrugarh town waste management is more critical compare to others as because of the open air dumping system since 25 years as well as proximity to river Brahmaputra dike area which is unsuitable and unscientific for dumping process. The intermixing of waste with riparian ecosystem leads to further complications and far-reaching consequences. There is a good scope of Biogas production and vermicompost generation from waste dumping areas because in average almost 90% waste is bio-degradable. There is immediate need of advanced technical measures to handle the waste management in these towns further.

Determination by Landsat Satellite Imagery to Local Scales in Land and Pollution Monitoring: a Case of Buyuk Melen Watershed (Turkey)

Buyuk Melen Watershed provides drinking water from the Western Black Sea region to Istanbul province, which Buyuk and Kucuk Melen rivers, Asar, Ugur and Aksu rivers. Many settlement areas, fertilized agricultural lands, industrial plants and solid/liquid waste dumping areas have present in Melen watershed, causing substantial pollution problems. Melen watershed has been at a serious risk of pollution that a lot of settlement areas, agricultural lands, industrial facilities, and solid and liquid waste. In this study, LANDSAT satellite data was used to monitor the status of this area on the potential of the region studied. In the watershed change of 1987, 2001, 2006 and 2010 and also supported by satellite data. However, contaminants in the watershed discharges to the inner parts as shown from the satellite data have also been observed that the increase in pollution.

Environmental Impact of Metal and Metal Containing Wastes on the Cadmium and Lead Contents of Leachate and Soils of the Aba-Eku Dumpsite, Ibadan, Nigeria

Aims: This study evaluated the impact of metal and metal containing wastes (plastics, glass, miscellaneous and fines) on cadmium and lead contents in soil and leachate and the inter-relationships among the various waste categories dumped on the site, using Principal Component Analysis (PCA). Study Design: Cadmium and lead contents in top soils of Sub-site WDA (Waste Dump Area) and LLA (Leachate Lagoon Area) (wdatscd, wdatspb; llatscd, llatspb); at 15-30cm depth i.e. sub-soil 1 (wdass1cd, wdass1pb; llass1cd, llass1pb); at 31-60cm depth i.e. sub soil 2 (wdass2cd, wdass2pb) and attenuated leachate cadmium and lead (alcd, alpb) were used along with the various waste fractions for PCA analysis. Place and Duration of Study: Department of Zoology, University of Ibadan, Ibadan, Nigeria. January 2003-September 2004; Institute of Applied Ecology, Shenyang, China. May 2006-May 2007. Methodology: Solid waste, leachate and soil were collected from two sub-sites (WDA and LLA and comparative control 600m away) from the Aba-Eku landfill site, Ibadan, Nigeria in February, April, August, October and December 2003; as well as in June 2004. Original Research Article Article British Journal of Applied Science & Technology, 4(11): 1693-1717, 2014 1694 They were analyzed for cadmium and lead contents using Inductively Coupled Plasma Spectroscopy after Hydrofluoric-Perchloric-Nitric acid digestion. Data obtained were subjected to PCA analysis. Results: The tendency of the various metal containing waste categories to cluster with lead and cadmium in leachate and soil on more than one principal component is suggestive of the degree of input to lead and cadmium contamination in soil and leachate. Metals contributed the highest (cluster on all three PCs) followed by plastics and the miscellaneous fraction (cluster on two PCs), glass and the fines fraction (cluster on one PC). Results also revealed two main clusters of biodegradable (Food wastes, miscellaneous and fines or soil) and non-biodegradable wastes (Glass/ceramics and metals). Conclusion: Based on these results, increased recovery and recycling of the metal, plastics and glass/ceramics waste fractions in particular, are suggested.

Open dumping of municipal solid waste and its hazardous impacts on soil and vegetation diversity at waste dumping sites of Islamabad city

Deteriorating soil quality and decrease in vegetation abundance are grave consequences of open waste dumping which have resulted in growing public concern. The focus of this study is to assess the contribution of open waste dumping in soil contamination and its effect on plant diversity in one of the renowned green cities of Pakistan. Surface soil samples (n=12+12) were collected from both the open waste dumping areas allocated by Capital Development Authority (CDA) and sub- sectors of H-belt of Islamabad city (representative of control site). The diversity of vegetation was studied at both sampling sites. Significant modifications were observed in the soil properties of the dumping sites. Soils at the disposal sites showed high pH, TDS and EC regime in comparison to control sites. Various heavy metal concentrations i.e., Lead (Pb), Copper (Cu), Nickel (Ni), Chromium (Cr) and Zinc (Zn) were also found to be higher at the dumping sites except for Cadmium (Cd) which had a higher value in control site. A similar trend was observed in plant diversity. Control sites showed diversified variety of plants i.e., 44 plant species while this number reduced to only 32 plant species at the disposal sites. This is attributed to changes in soil characteristics at disposal sites and in its vicinity areas.

Survey on heavy metals contaminated soils in Thai Nguyen and Hung Yen provinces in Northern Vietnam

In Vietnam, soil contamination with lead and cadmium at very high level was investigated and discovered in the surrounding areas of zinc-lead mining and processing factory in Tan Long (Dong Hy district, Thai Nguyen province) and around the lead-recycling smelter in Chi Dao (Van Lam district, Hung Yen province). The survey on soil contaminated by arsenic due to the tin mining and sifting activities in Ha Thuong (Dai Tu district, Thai Nguyen province) was also carried out. In Tan Long, the concentrations of lead and cadmium in the old solid waste dump from zinc-lead factory varied from 1,100 to 13,000 mg·kg-1, and from 11.34 to 61.04 mg·kg-1, respectively. Soil Pollution Indexes (SPI) of lead and cadmium were highest in the old solid waste dump area, followed by the ones in the rice paddy soils. In Chi Dao, the soils of many sites were polluted with lead and cadmium such as in the gardens of lead-recycling households where the concentrations of lead and cadmium were 7,000 - 15,000 mg·kg-1 and 1.8 - 3.6 mg·kg-1. In rice paddies, the soils were also polluted by lead. SPI of lead in paddy soil areas within 300 m radius from the lead smelter were from 3.6 to 100 fold higher than the safe limit. The sediment from the ditch near the lead smelters contained extremely high levels of lead (7,000 - 110,000 mg·kg-1) and cadmium (3.8 - 17.7 mg·kg-1). The tin mining and sifting activities in Ha Thuong was the cause for the arsenic contamination of the soil in this area. The arsenic contents in soils at all locations investigated were higher than 320 mg·kg-1 (dry weight) and up to 3,809 mg·kg-1.&#x0D; Tại Việt Nam, đất bị ô nhiễm bởi chì và ca-đi-mi với hàm lượng cao đã được điều tra phát hiện ở các khu vực phụ cận của nhà máy khai thác và chế biến kẽm/chì thuộc địa phận xã Tân Long, huyện Đồng Hỷ, tỉnh Thái Nguyên và các khu vực phụ cận củalòtái chế chì thuộc địa phận xã Chỉ Đạo, huyện Văn Lâm, tỉnh Hưng Yên.Sự khảo sát đất bị ô nhiễm bởi a-sen do các hoạt động khai thác và tuyểnthiếc ở xã Hà Thượng, huyện Đại Từ, tỉnh Thái Nguyên cũng đã được tiến hành. Tại xã Tân Long, nồng độ chì và ca-đi-mitrong bãi chất thải rắncũtừ nhà máy sản xuất kẽm chì là 1.100 - 1.300 mg.kg-1 và từ 11,34 đến 61,04 mg.kg-1, tương ứng. Chỉ số ô nhiễm đất (SPI) của chìvà ca-đi-micao nhất trongkhu vực đổ chất thải rắn cũ, tiếp theo sau là ở các ruộng lúa. Tạixã ChỉĐạo, đất ở nhiều địa điểmđã bị ô nhiễm chìvà ca-đi-mi chẳng hạn như trong khu vườn của các hộ gia đình tái chế chì, nồng độ chìvà ca-đi-milà 7.000 - 15.000 mg.kg-1 và 1,8 - 3,6 mg.kg-1. Trong cánh đồng lúa, đất cũng bị ô nhiễm bởi chì. Chỉ số ô nhiễm đất của chì (SPI-Pb) trong cánh đồng lúa trong vòng bán kính 300 m từ lò tái chế chì cao hơn giới hạn của đất an toàn từ 3,6 đến 100 lần. Trầm tíchthutừ kênhgần lòtái chếchì chứa hàm lượngchìrấtcao (7000 - 110.000 mg.kg-1) và ca-đi-mi (3,8 -17,7 mg.kg-1). Việc khai thác và tuyển thiếc tại xã Hà Thượng đã gây ra ô nhiễm a-sen trong đất tạikhu vực này. Hàm lượng a-sentrong đất tại tất cả các địa điểm nghiên cứu cao hơn 320 mg.kg-1 (trọng lượng khô), đặc biệt là lên đến 3809 mg.kg-1.

Heavy metal pollution assessment through comparison of different indices in sewage-fed fishery pond sediments at East Kolkata Wetland, India

The sediments of the raw sewage-fed fishpond system at East Kolkata Wetland (EKW) were analyzed for heavy metal content in a comprehensive way. Various indices of contamination like enrichment factor (EF), geo-chemical index (Igeo), modified degree of contamination (mDC), and pollution load index (PLI) were assessed. In all cases, instead of literature values, the metal concentrations of less contaminated sites, separated by the statistical approach of the hierarchical cluster analysis, were used as baseline values. In the present study, about 70% of the pond sediments are found uncontaminated, 5% display low degree of contamination and 25% are designated as moderate degree of contamination. Both the EF and Igeo indices highlighted that the metals lead (Pb), cadmium (Cd), and chromium (Cr) are responsible for the contamination while there is little anthropogenic input in cases of Cu, Zn, and Ni. Most of the ponds situated near the main sewage flowing canals as well as the main traffic highway and close to the solid waste dumping areas recorded higher degree of metal contamination as evident from spatial variation of mDC and PLI indices in the study area. Indices comparison study clearly indicates that although these are calculated using different methods, these may or may not produce the same indices values and hence the values should neither be compared nor be averaged. But all the above indices are directly related to a common term contamination factor (CF). Classification of contamination levels based on these CF values is found to be similar and this classification is only valid up to the level of high degree of contamination. Thus, the use of any one of these indices is sufficient to classify the degree of contamination of an area. However, to evaluate the contamination per metal, both Igeo and EF are effective while, to assess the composite effect of all the metals, PLI is preferable to mDC.