Waste Dumpsite Research Articles

Analytical hierarchy process tool in Google Earth Engine platform: a case study of a tropical landfill site suitability.

Kolkata being a metropolitan city in India has its main municipal solid waste dumpsite situated at Dhapa just adjacent to the East Kolkata Wetlands (Ramsar site). The current prevalent situation at Dhapa is open dumping leading to various contaminations and hazards putting forth the need to look for alternative sites where the landfiilling operation can be shifted to using scientific methods. A user interface (UI)-based analytical hierarchy process (AHP) tool has been developed within the Google Earth Engine (GEE) cloud platform to find out the alternative dumping sites using geospatial layers. AHP function is not available as a native algorithm or developed by any researcher in GEE. The tool has three major functionalities, of which the first one handles the UI elements. The AHP procedure is within another function, and the last function integrates the AHP coefficients to the layers generating the final suitability layer. Users can also upload comparison matrix as GEE asset in the form ofCSV file which gets automatically integrated into the AHP to calculate the coefficients and consistency ratio to generate the spatial suitability layers. This approach showcases a generalized AHP function within the GEE environment, which has been done for the first time. The tool is designed in the cloud platform which is dynamic, robust and suitable for use in various AHP-based suitability analysis in environmental monitoring and assessment.

An integrated approach to explore the suitability of nitrate-contaminated groundwater for drinking purposes in a semiarid region of India

The main objective of the present study is to perform risk assessment of groundwater contaminated by nitrate (NO3−) and evaluate the suitability of groundwater for domestic purposes in the Palani region of South India. Thirty groundwater samples were collected in the study area. Various groundwater quality analysis parameters such as the pH, electrical conductivity, total dissolved solids, total hardness, major cations (Ca2+, Mg2+, Na+, and K+), and major anions (Cl−, SO42−, F−, CO32−, and HCO3−) were adopted in this study to evaluate the drinking water suitability according to 2011 World Health Organization (WHO) standards. Piper and Gibbs’s diagrams for the tested groundwater indicated that, due to the influence of rock–water interactions, evaporation, and reverse ion exchange, the chemical composition of groundwater varied. According to water quality index (WQI) mapping results, 46.67% of the sample locations was identified as contaminated zones via GIS spatial analysis. Multivariate statistical analysis methods, such as principal component analysis, cluster analysis, and the Pearson correlation matrix, were applied to better understand the relationship between water quality parameters. The results demonstrated that 40% of the samples could be identified as highly affected zones in the study region due to a high nitrate concentration. The noncarcinogenic health risks among men, women, and children reached 40, 50, and 53%, respectively. The results illustrated that children and women occurred at a higher risk than did men in the study region. The major sources of contamination included discharge from households, uncovered septic tanks, leachate from waste dump sites, and excess utilization of fertilizers in the agricultural sector. Furthermore, using the nitrate health hazard integrated method with the conventional indexing approach ensures that groundwater reliability can be guaranteed, contamination can be explored, and appropriate remedial measures can be implemented.

Multiple heavy metal immobilization and strength improvement of contaminated soil using bio-mediated calcite precipitation technique.

Bio-mediated calcite precipitation potential for multiple heavy metal immobilization in contaminated soils at industrial, waste dump, abandoned mine, and landfill sites is not explored yet. This study includes investigation of bio-mediated calcite precipitation for strength improvement and immobilization of heavy metals, specifically lead (Pb), zinc (Zn), and hexavalent chromium (Cr(VI)), in contaminated soils. Firstly, the toxicity resistance of bacteria against different concentrations (1000, 2000, 3000, 4000, and 5000 mg/l) of each heavy metals was investigated and observed that Pb and Cr were less toxic to Sporosarcina pasteurii than Zn. The poorly graded sand was spiked with 333-2000 mg/kg concentrations of a selected individual or mixed metal solutions, i.e., 1000 mg/kg and 2000 mg/kg individual concentrations of Pb, Zn, and Cr(VI); 500 mg/kg and 1000 mg/kg concentration of each metal in "Pb and Zn," "Pb and Cr(VI)," and "Zn and Cr(VI)" mixture of heavy metals; and 333 mg/kg and 666 mg/kg concentration of each metal in "Pb, Zn, and Cr(VI)" mixed metal concentration. Contaminated soil was biotreated with Sporosarcina pasteurii and cementation (a solution of urea and calcium chloride dihydrate) solutions for 18 days. Biocemented sand specimens were subjected to testing of hydraulic conductivity, ultrasonic pulse velocity (UPV), unconfined compressive strength (UCS), calcite content, pH, toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The heavy metal contaminated samples showed decrease in hydraulic conductivity and increase in UPV and UCS after biotreatment; however, the changes in engineering properties were found more moderate than clean biocemented sand. The conversion of Cr(VI) to Cr(III) followed by Cr2O3 precipitation in calcite lattice was observed. Zn was precipitated as smithsonite (ZnCO3), while no Pb precipitate was identified in XRD results. TCLP leaching showed Pb and Cr immobilized proportional to calcite precipitated amount, and higher calcite amounts yielded levels within regulatory limits. Pb and Cr(VI) immobilization up to 92 % and 94 % was achieved, respectively, in contaminated biocemented sand. Zn was found completely leachable as smithsonite is only stable down to pH~5, and strongly acidic TCLP solution reversed all immobilization at natural soil pH~8-9.

Examining the Effect of Spatial Proximity of Geo-located Dumpsites on Groundwater Quality in Samaru-Nigeria

The effect of improper waste disposal on man’s health and environment due to the closeness of solid waste dumpsites to underground water sources in some parts of the world has raised issues of serious concern. This study thus sought to examine groundwater quality dependence on the spatial proximity of dumpsites in Samaru, Kaduna state-Nigeria. The coordinates of 10 solid waste dumpsites in proximity to groundwater sources (boreholes) in the study area were acquired for spatial analyses with a GPS-enabled smartphone. Ten groundwater samples from boreholes in relation to dumpsites were collected for testing and analyses of 11 physical and chemical parameters of water quality based on the Canadian Council of Ministers of the Environment (CCME) and World Health Organisation (WHO) standard limits. Thereafter, the water quality index (WQI) for all the locations was calculated. The results of the spatial proximity analyses carried out revealed that the requirement for locating dumpsites was not met as specified by the Environmental Protection Agency (EPA) regarding the minimum safe distance from groundwater sources as a majority (about 80%) of the dumpsites were located too close to the boreholes. The results of the study, however, revealed that the majority (about 80%) of the groundwater samples met the conditions for good drinking water (suitable for drinking water) even with their closeness to the dumpsites based on the computed WQI values and ratings. Meanwhile, only Calcium, Dissolved Oxygen, and Biochemical Oxygen Demand concentrations were significantly affected (p < 0.05 at the 95% significance level) by the closeness of the solid waste dumpsites to the boreholes with very strong (R2 = 86%) and strong (R2 = 79%) relationships, respectively. Suggestions were nonetheless made for the monitoring of land use activities in the areas surrounding groundwater sources to prevent groundwater contamination.

Locating Suitable Solid Waste Dumping Sites using Remote Sensing and GIS Techniques in Aba Municipal, South-Eastern Nigeria

In most cities of Nigeria, indiscriminate solid waste dumping sites have taken over roadways, clogging drainage systems and slowing traffic flow. Conditions arising from indiscriminate waste disposal can lead to contamination of the environment and outbreaks of diseases. The main objective of this study was to examine the existing and predict potential suitable areas for solid waste dumping in Aba municipal in South-eastern Nigeria. The data used for this study were Landsat image; elevation map, ground control point of existing solid waste dumping sites, and topographical sheets of the study area. The maps were prepared by overlay and multi-criteria thresholds of roads, settlement, slope and distance to stream, We found that that 65% of the solid waste dumping area located close to roads and clustered in densely populated areas around the city center The final predictive suitability map for locating solid waste dumpsites indicated that, 11.35sqkm (19.41%) is not suitable, 26.47sqkm (45.25%) is less suitable, 16.17sqkm (27.65%) is moderately suitable and 4.5sqkm (7.69%) is highly suitable for Solid waste disposal. The potential most suitable areas for solid waste dumping sites fall about 5000m west of Ariaria market and 10,000m south east of Umu Mba in Aba Municipal.

Polycarbonate plastic monomer (bisphenol-A) as emerging contaminant in Nigeria: Levels in selected rivers, sediments, well waters and dumpsites

Despite decades of research into the environmental fate and levels of the endocrine-disrupting polycarbonate Plastic monomer, bisphenol-A (BPA), data remain scarce from many developing countries. Here, occurrence and levels of BPA were investigated in water and sediments of three rivers, selected dumpsites and well waters in Ondo State, Southwestern Nigeria. The study also investigated the influence of matrix physicochemical characteristics on their BPA retention. BPA values ranged from 0.41–5.19 μg/L in river waters, 0.64–10.6 μg/kg in river sediments, 0.63–0.68 μg/L in well waters and 0.72–1.09 μg/kg in waste dumpsites. BPA concentrations in the river waters showed a strong association with chemical oxygen demand (COD) values. High BPA concentrations were also found associated with high chloride contents of drinking well waters. Detection in river and well waters revealed exposure routes of humans, cattle and aquatic species to BPA in the region.

Assessment of Health and Safety Risk Among Waste Scavengers in Enugu State, Nigeria

One of the most dangerous and dehumanizing activity in many developing countries is waste scavenging, an act of selecting possible useful or materials from waste materials especially at waste dump sites for purposes of making a living. This act exposes waste scavengers to several occupational health risks and hazards ranging from cuts, needle stick injury, and exposure to particulate matter, disease causing organisms, contaminated food and water, unhygienic working environment, among other health hazards. In Nigeria, population growth has resulted in an uncontrolled increase in waste creation, making it impossible for waste management organizations in various states to cope. Thus, increasing the number of waste scavengers who use waste picking as a daily source of income and a routine vocation to reduce the unemployment gap. This study was therefore performed to assess health and safety risk among waste scavengers in Enugu state, Nigeria with a view to identifying health conditions associated with waste scavengers in the state. This research adopted a descriptive cross-sectional approach in sampling 396 wastes scavengers across the three senatorial districts of Enugu state. A multistage and random sampling technique with instruments of questionnaires as well as risk assessments of the dumpsites were used to achieve the research objectives. Findings revealed that most of the respondents were exposed to all types of hazards with (79.8%) prevalence of physical hazard, (52.3%) prevalence of biological hazard, (61.6%) prevalence of chemical hazard, (60.6%) prevalence of psychological hazard and (95.7%) prevalence of ergonomic hazard. Due to exposures to broken glasses, needles, nails, metals, bottles, trips and falls, dust, machinery, computer equipment, woods, faeces, used condoms, food wastes, decaying materials, insects, rats, snakes, battery, poisoning from insecticides, decaying materials, chemical substances, lifting heavy bags of picked solid waste materials such as metals and plastics. Study recommends the use of PPEs by scavengers and enforcement of the use by government to ensure their exposures to some of these hazards are reduced. Also, recommends collaboration of Government with health workers to organize frequent health education and promotion to educate the waste scavengers on various types of health hazards.

Geoelectrical and Geochemical Investigations of Selected Dumpsites for Potential Groundwater Contamination in Gusau, Zamfara State, Nigeria

Groundwater contamination has been a worldwide phenomenon. In this research, geoelectric and geochemical surveys were carried out on three active dumpsites in Gusau metropolis for detection of groundwater contamination. Vertical electrical Soundings (VES) were conducted on the dumpsites using Schlumberger array with maximum current electrode separations of 180 m. Five VES were conducted on each dumpsite making a total of fifteen VES along three profiles. Thirty five (35) points were assessed from three wastes dumpsites using portable XRF equipment for the in-situ testing while fifteen (15) representative groundwater samples collected were taken to the laboratory for hydro-geochemical analysis. The field data obtained from VES was analyzed using WinGlink software. The VES results revealed three subsurface layers. The topsoil has resistivity ranging from 1.5Ωm to 48.2 Ωm while the thicknesses vary from 0.47 m to 3.37 m across the profiles. The second layer’s resistivity varies from 5.4 Ωm to 144.35 Ωm and their thicknesses’ ranges from 1.36 m to 16.93 m. The third geoelectric layer has resistivity from 70.0 Ωm to 6003.0 Ωm. The geoelectric results revealed that the top soils in all the dumpsites were characterized by very low resistivity depicting possible pollution and contamination. Environmental pollution models applied to the geochemical dataset revealed Zn, Pb and Cu as moderately contaminants which generally indicated severe potential contamination in the investigated area. While other analytic parameters such as Mn, Cr, Ni and Fe showed low contamination factors. Hydro chemical analysis showed that pH values recorded from the water samples ranged between 7.26 to 8.12 with mean value of 7.50, whereas, recorded Total dissolve solid (TDS) ranged between 377 to 1393mg/L with average concentration of 751.27mg/L. Findings from the study indicated that there may be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are not taken into consideration at the dumpsites.

Estimation of spontaneous waste ignition time for prevention and control of landfill fire.

Openmunicipal solid waste(MSW) dumpsites in India are significant hotspots of spontaneous fire and associated air and ground water pollution. Unscientific dumping of MSW poses a major threat to the surrounding environment and human health. One-year-old biodegradable waste components comprised of paper, cardboard, newspaper, textile, wood, grass leaves and coconut shell were analyzed for the determination of the moisture content (MC), smoldering temperature, ignition temperature, and ignition time. Principal component analysis of the old waste components revealed that cardboard, paper, newspaper and leaves are most susceptible waste components for spontaneous ignition. In contrast, MC was the most influential parameter for resulting changes in ignition temperature (0C) on ignition time (min). A numerical equation was developed to estimate the time required for the spontaneous waste ignition at MSW dumpsite. The results of the study showed that the aged waste (age≥3year) having MC below 6 % and initial surface temperature of 78 0C might smolder and ignite during the hottest time of the day in∼6 and∼26days, respectively. Estimates showed that the time required for spontaneous waste ignition of aged waste is moderately dependent on waste MC (∼5-55 %), surface temperature (∼40-100 0C), monthly pattern of average high temperature (∼36.6-42.6 0C), biodegradable waste components having smoldering temperature≤150 0C and ignition temperature≤270 0C. The present study also showed that the occurrence of landfill fire events at MSW dumpsites is more prominent during the pre-monsoon season i.e. during the elevated temperature level.

Factors Affecting the Intensity of Color Released In Water Extract by Soil-Like Material Obtained From Mining of Old MSW Dumps

This paper presents the analysis of release of dark-colored leachate from soil-like material (SLM) mined from three old municipal solid waste dump sites of before its reuse as earth-fill. If SLM is to be re-used in earth-fill, the release of dark-colored leachate can cause coloration of the surrounding water bodies. Laboratory studies (in terms of single batch leaching) were undertaken to quantify the release of color and identify the source/cause of the phenomenon. Influence of repeated washing, heating at various temperature, and aeration of SLM on the intensity of release of color was identified. Correlation of color with total dissolved solids and volatile dissolved solids was also established. The intensity of color of water extract from SLM in platinum cobalt unit (PCU) was found to in the range of 288-712, 465-485 and 740-925 from Delhi, Kadapa and Hyderabad dumpsites respectively. In contrast, the intensity of color in water released from local soils was found to be 25-30 PCU. Organic content present in SLM was identified as the primary cause for the release of color. Results showed that large quantity of water (70-120 ml per gram of SLM) was required to cause significant reduction in the intensity of color. Heating of SLM to 500°C was observed to reduce the color very effectively but short-term aeration of SLM did not reduce color. Good correlation of volatile dissolved solids with color was observed which further confirmed the organic content as the main reason for the release of dark-colored leachate from SLM.

Health risk assessment for exposure to heavy metals in soils in and around E-waste dumping site

Electrical and electronic waste recycling is done mainly by the informal (unauthorised) sector in developing countries. People usually dump these wastes in an open area leading to contamination of air, soil, and water. The objective of this study was to assess heavy metals contamination of soil and quantify and compare human health risks based on two different methods i.e., using epidemiological data, and US EPA’s methodology for risk assessment due to exposure to toxic heavy metals. The study was conducted by collecting soil samples from an electronic waste dumping site in Sangrampur, West Bengal (India) in 2018. Sangrampur is well-known for its informal electronic waste management activities. Heavy metals such as Pb, Cr, Mn, Fe, Co, Ni, Cu, and Cd were detected in the soil from the dumping site using i-CAP Q Inductively Coupled Plasma Mass Spectrometry. Based on epidemiological data, the Relative Risk and Attributable Risk were 1.377 (95% confidence interval of 1.2314–1.4249) and 0.069, respectively. The Odds Ratio was 1.501 (95% confidence interval of 1.3456–1.6733). Relative Risk and Odds Ratio values are statistically significant implying that the workers treating these waste without safety measures have a higher risk of cancer compared to the general population. The non-carcinogenic risk for a child was greater than for an adult in the study area. Based on chromium data alone, the carcinogenic risk was found to be 6.1 × 10−7 in children and 1.57 × 10−7 in an adult. These values are less than the permissible limit of 10−6 for residential areas.

Evaluation of heavy metal content and potential ecological risks in soil samples from wild solid waste dumpsites in developing country under tropical conditions

Solid waste management constitutes a major concern and unresolved problem in most parts of the world, particularly in developing countries where solid waste is disposed in unregulated dumpsites in the public spaces. This practice can lead to contamination of environmental compartments such as soil, surface and groundwater which could negatively impact human health. In this study, surface soil samples were collected from 15 selected solid waste dumpsites in Kinshasa City (Democratic Republic of the Congo) to examine the heavy metal content and potential environmental risks. The results highlighted a high concentration of metals in soil samples compared to local background values and international threshold. The average concentration of metals in all soil samples followed generally the order: Zn>Pb > Cu >Cr> Co> Cd> As> Hg. The calculated pollution indexes including Geo-accumulation, Enrichment Factor, Contamination degree and Potential Ecological Risk, revealed polymetallic contamination dominated by several of these metals in which Zn, Cu, Pb and Hg were of greatest concern indicating high environmental risks. This work showed that illegal wild landfills represent a real danger for the environment and human health. Due to the toxicity of heavy metals, the measures to establish a monitoring program that address uncontrolled landfills and solid waste management and disposal are recommended to reduce the load of contaminants in soils which can reach surface and groundwater. On the other hand, the use of manures from these dumpsites for agricultural purposes should be discouraged because they may be easily absorbed at alarming levels by vegetables.

Geo-spatial Analysis of the Impacts of Urbanization-induced Activities on Soil Quality in Port Harcourt Metropolis, Rivers State-Nigeria

The study examined the impacts of urbanization-related activities on soil quality in Port Harcourt Metropolis-Rivers state, Nigeria. Experimental and survey research designs were implored in the study utilizing GIS and spatial analysis approaches. Both primary and secondary sources of data were used. The primary data were generated through laboratory analysis of soil samples from 15 randomly selected sites within the metropolis;and 800 valid copies of socio-economic questionnaire administered to 800 respondents. Also, public hospitals were visited to ascertain the commonest soil borne diseases in the area. Four research questions, four specific objectives and two hypotheses guided the study. The hypotheses were tested with one sample t-test and one sample chi square using SPSS. Standard scientific and laboratory procedures were followed in the collection and analysis of soil samples. Findings of the study include: urbanization-related activities (e.g. waste dumpsites, mechanic workshops, abattoirs, etc.) cause significant changes on soil quality in the area; and this result to the emergence of soil borne diseases (e.g. Vascular witts, Ascaris lumbricoids,Trichuris trichiura, Strongloids stereoralis) which affects residents’wellbeing. However, there is significant difference in the perceived socioeconomic effects of the diseases across the area. Specifically, laboratory results for soil analysis show that (mean values): pH 7.22, temperature 25.62 °C, PO4 0.342 mg/kg, Pb 120.62 mg/kg, K 66.81 mg/kg, NO3 mg/kg. The study recommended for enforcement of physical planning and development control laws; regular evaluation of the quality of the soil, and restriction on the location of mechanic workshops and waste dumpsites around the metropolis.

Production of α-amylase from Aspergillus flavus S2-OY using solid substrate fermentation of potato (Solanum tuberosum L.) peel

Amylases find commercial applications in diverse industries. This study investigated the production of α-amylase from a fungus, using potato peel as an alternative substrate. Six fungal isolates from the soil of cassava waste dumpsite were tentatively identified as two Aspergillus species and one species each of Rhizopus, Trichocladium, Neosartorya and Ascodermis. They were screened for their relative amylolytic activities using the starch agar hydrolysis test. Molecular characterization, using the ITS rRNA gene sequencing, was used to confirm the identity of the selected fungus as Aspergillus flavus S2-OY. Amylase production from the fungus via solid substrate fermentation of potato peel was carried out and the effect of production parameters investigated. Maximum α-amylase production was at an incubation period of 72 h, pH of 5.0 and temperature of 25 °C. Casein and maltose were the best nitrogen and carbon sources, respectively while the optima inoculum and moisture volumes for enzyme production were 1.5 mL and 5.0 mL, respectively. Aspergillus flavus S2-OY has great potential for α-amylase production using potato peel as an alternative and cheap substrate, under solid substrate fermentation condition. This has implications for the cost-effective production of an industrial enzyme and reduction of environmental pollution problems through effectual management of agro-industrial wastes.

Index Model Approach of Heavy Metals Pollution Assessment in Soil Quality of some Selected Solid Waste Dumpsites in Warri and Environs, Delta State, Nigeria

Index Model Approach of Heavy Metals Pollution Assessment in Soil Quality of some Selected Solid Waste Dumpsites in Warri and Environs, Delta State, Nigeria

Polycyclic aromatic hydrocarbons in soil situated around solid waste dumpsite in Awka, Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in the environment that can threaten the populace living close to contaminated soil. Soil samples were collected from the study and control areas which were analyzed for PAHs using Gas chromatography. The detected PAHs concentrations varied from ND to 6.83 ± 10.58 µg/kg for the study sample and ND − 3.23 ± 4.72 µg/kg for the control sample for the wet season. The study sample dry season concentration values of PAHs ranged from ND to 4.73 ± 5.69 µg/kg and varied from ND to 3.67 ± 5.49 µg/kg for the control sample in the dry season. The study sample ( ∑ PAHs) values were significantly higher than the control location in both seasons. The detected 2–3 ringed PAHs values were higher than the 4–6 ringed PAHs for both locations and seasons. The ratios of the molecular groups indicated that the PAHs were delivered to the soil from pyrolytic and petrogenic sources. The values of the cancer risks for adults and children ranged from 1.02 × 10 − 9 − 5.68 × 10 − 10 to 2.27 × 10 − 9 − 4.3 × 10 − 9 for dermal and ingestion pathways respectively which makes cancer risks unlikely for both age categories in both locations.

Identification of solid waste dumping site suitability of Kolkata Metropolitan Area using Fuzzy-AHP model

The solid waste management (SWM) issue become a hot topic since the early 21st century, owing to the massive increase in global human population. This study centered on a most important urban center of Eastern India, the Kolkata Metropolitan Area (KMA) having a total population of nearly 14.72 million with an average per capita waste generation of about 383.89 gr/person/year, necessitating the identification of new landfill areas to handle such a massive waste load. Therefore, the current work tried to explore the most suitable new dumping sites for the KMA, taking into account 4 main (topographical and geomorphological, lithological, socio-economic, and hydrogeological) and 17 sub-parameters from aforementioned four main data groups, as suggested by the Central Pollution Control Board's guidelines. With this Fuzzy-Analytical Hierarchy Process (F-AHP) and weighted linear combination model was used to determine the weightage and ratings of the main and Sub-parameters. Result indicates that 40.59% of the study area is not suitable for dumping site construction, 29.34% is least suitable, 14.34% is moderate suitable and about 9.64% is under highly suitable zone. Furthermore, a site-based verification report reveals that over 15 spots, in different parts of the study area may have a potential for dumping of large volume of urban solid waste. Six of them might be the finest candidates for Kolkata, Howrah, and Chandannagar MC, the three municipal corporations of KMA. As such, considering all the topographical, environmental, social, hydrogeological components, the public sectors and city planners can follow and refer the result of this suitability analysis.

Evaluation of the transport and mobility of Co(II) in soils from agricultural, waste dump and an automobile repair shop sites in Bambili-Cameroon

This study investigated the transport and mobility of Co(II) in swampy agricultural soil (SS1), soil from waste dump site (SS2) and soil from automobile repair shop site (SS3) all from Bambili-Cameroon. Column filtration experiments with Co(II) concentrations of 10, 100 and 500 mg/L were used. Breakthrough curves were used to evaluate Co(II) mobility. At 10 mg/L, Co(II) there was no mobility for all three soil samples, at 100 mg/L, no mobility was observed in SS2 but 6.398 mg/L and 2.081 mg/L of Co(II) detected in the effluent of SS3 and SS1 respectively. Cobalt transport was faster in SS1 with 9180 mL of effluent collected in 2331.59 min followed by SS3 with 1545 mL of effluent collected in 2072.59 min and lowest in SS2 with 1040 mL of effluent collected in 2356.49 min. No saturation point was reached for any of the soil samples despite filtration for over 2500 min on average. For SS1, maximum C/C 0 was 0.5 for 100 and 500 mg/L and 0 for 10 mg/L. For SS2, maximum C/C 0 was 0.3 for 500 mg/L and 0 for 10 and 100 mg/L. For SS3, maximum C/C 0 was 0.6 for 500 mg/L in 2000 min and 0.1 for 10 and 100 mg/L in 2500 min. When the soils were acidified with 0.5 M H 2 SO 4 , the breakthrough times reduced from about 2500 min to 8, 132 and 27 min for SS1, SS2 and SS3 respectively for 500 mg/L and soils saturating in about 1000 min. The order of Co(II) transport is SS1 > SS3 > SS2 and mobility is SS3 > SS1 > SS2. These results for Co(II) mobility tie with the sandy fractions of 58.7, 55.1 and 65.6% for SS1, SS2 and SS3 respectively with corresponding gravel of 3.6, 5.2 and 5.9% while those of Co transport tie with soils bulk densities of 0.09, 1.2 and 1.0 g/cm 3 for SS1, SS2 and SS3 respectively. A surveillance system should be installed in zones where these activities are taking place to check and provide timely remediation techniques to eliminate heavy metals pollution. • The transport and mobility of Co(II) in swampy agricultural soil, soil from waste dump site and soil from automobile repair shop site was studied. • Co(II) transport is fastest in swampy agricultural soil followed by soil from waste dump site and lastly on soil from automobile repair shop. • Co(II) mobility is fastest in soil from waste dump site followed by swampy agricultural soil and lastly on soil from automobile repair shop. • Co(II) transport through the soils is influenced by their bulk densities while Co(II) mobility was influenced by soil particle distribution. • Increasing the acidity of the tested soil samples significantly increase Co(II) mobility as the saturation of the soil occurs in a very short time.

Assessment of vanadium pollution and ecological risk in some selected waste dumpsites in Southeastern Nigeria

Waste disposal on dumpsites has resulted in significant vanadium pollution of the soil and ecosystem. This study assessed the pollution status and potential ecological risk of vanadium in some selected waste dumpsites in southeastern Nigeria. In this study, the soil samples were taken from the active waste dumpsites using a stainless-steel soil auger at a depth of 0 - 20 cm. Five sub-samples were taken from each sample location. A control sample was taken from an area devoid of industrial activities and waste dumps. Soil samples were air-dried at room temperature, pulverized with an agate mortar and pestle, and stored using appropriately labeled polythene bags prior to analysis. Vanadium analysis was conducted using an FS240AA atomic absorption spectrophotometer, and the data generated was analysed using IBM SPSS version 20.0 and Ms-Excel 2007. The mean vanadium concentrations in the studied waste dumpsites were found to be in the following order: Okpuno-Egbu dumpsite > Nekede dumpsite > Enyimba dumpsite > Rice-mill dumpsite. Acceptable potential ecological risk indices were observed in the Rice-mill, Enyimba, and Okpuno-Egbu dumpsites, while Nekede dumpsite recorded a high potential ecological risk. Furthermore, the pollution load index revealed that all the studied dumpsites were heavily polluted. Statistical analysis revealed no significant variations in vanadium concentrations in the studied dumpsites (p>0.05). Additionally, there was a strong and positive correlation between the dumpsites of Enyimba/Nnewi (r = 0.634), Nekede/Nnewi (r = 0.615), and Nekede/Rice-mill (r = 0.842). This indicated that the metal found in the dumpsites is of the same origin.

Leachate analysis of two waste dumpsites in Pretoria, South Africa

Improper waste management practices may increase concentrations of noxious chemicals in leachate. This study analysed concentrations of trace metals in leachate collected from two waste dumpsites in Pretoria, South Africa. An open ended questionnaire was implemented to managers to gather information on management options. Leachate samples were collected in triplicates from leachate ponds and stored below 10°C. Trace metal contents from samples were analysed using inductively coupled plasma mass spectrometry-7700 (ICP-MS-7700). Significant differences in the concentrations of trace metals were analysed using the student t-test. Both sites lacked leachate collection and treatment systems and official recycling programmes. The levels of lead (Pb), manganese (Mn), chromium (Cr), mercury (Hg), arsenic (As) and nickel (Ni) were above the recommended limits. Significant differences in trace metal concentrations were established at both dumpsites. Proper waste management can reduce concentrations of trace metals levels and environmental contamination.