Dumpsite Soil Research Articles

Chemical fractionation and mobility factor of some heavy metals in refuse dumpsite soil in Awka Metropolis, Anambra State, Nigeria

The geochemical forms of some heavy metals in refuse dump soils at Agu-Awka, Awka metropolis was studied in order to assess the mobility and bioavailability of the metals and hence their potential environmental risk. Exchangeable fraction (F1) contained the % fraction of 13.23% for Cd, 17.43% for Cr, 14.63% for Pb, 12.40% for Ni, 25.34% for Zn and 15.92% for Mn and these are in the order of Zn ˃ Cr ˃ Mn ˃ Pb ˃ Cd ˃ Ni. The carbonate fraction (F2) contained the % fraction of 17.08% for Cd, 17.84% for Cr, 9.20% for Pb, 28.32% for Ni, 13.76% for Zn and 8.49% for Mn and these are in the order of Ni ˃ Cr ˃ Cd ˃ Zn ˃ Pb ˃ Mn. Lead was predominantly associated with organic fraction with a result of 42.64% followed by chromium and manganese with the values of 22.48% and 20.00% respectively. The organic bound metals were in the abundance trend of Pb ˃ Cr ˃ Mn ˃ Cd ˃ Ni ˃ Zn. The highest values of metal in Fe-Mn oxide phase was manganese with a value of 32.18%, followed by cadmium with the value of 21.76%. The values of the other metals bound to this phase were 17.52%, 16.64%, 13.99% and 12.90% for Zn, Ni, Cr, and Pb respectively. Zinc with the value of 32.20% was predominantly associated with the residual fraction. The other metals bound to this phase had their values to be 30.13% for cadmium, 28.24% for chromium, 20.61% for lead, 29.41% for nickel and 23.37% for manganese. The mobility factor values of the metals were relatively low and they followed the order of Ni > Zn > Cr > Cd > Mn > Pb. That notwithstanding, soils from studied area should be carefully monitored to prevent the release of these metals due to redox reactions which may make them available to plants through absorption.

Determination of some heavy metals and physicochemical properties in contaminated soils of open waste dumpsite in Awka, Anambra State

The current study was designed for the assessment of cadmium, chromium, lead, nickel, zinc and manganese and some physicochemical properties of soils collected from an open dumpsite in Awka, Nigeria. Soil samples at the depth (0-20 cm) were randomly collected at the dump field and were analyzed for physicochemical parameters and heavy metals using standard analytical methods. The results show that the main dumpsite had a high sand content (91.48% ± 0.26%) with a low silt 4.07% ± 0.03% and clay 4.65% ± 0.00%. The pH of the dumpsite soils was 6.07 ± 0.04 which is an acidic pH. Organic matter (%) and organic carbon (%) were 3.84 ± 0.06 and 2.23 ± 0.04 respectively. The EC (µS cm-1) was 476.9 ± 0.00 while the ECEC (cmol/kg) 18.93 ± 0.04. The bulk density (g cm-3) was 1.32 ± 0.00 and the porosity (%) of the dump soil was 41.40 ± 0.00. Total metal concentrations of Cd, Cr, Pb, Ni, Zn and Mn were also analyzed and the concentrations of the heavy metals at dumpsitewas obtained (28.35 ± 0.21 to 149.10 ± 0.01 mg/kg). Metal contamination at dumpsite was in the order of Mn ˃ Zn ˃ Pb ˃ Cd ˃ Cr ˃ Ni. The study evidently indicates the presence of heavy metal contamination in the dumpsite even though some of them fell below the critical permissible concentration level. However, it is their accumulation and persistence in the soils of the dump site that may be a cause of concern for their surrounding environment and organisms.

Status of Selected Heavy Metals in Soils Samples Obtained From Crown Estate Dumpsite, Okada, Edo State, Nigeria

This research work focused on the status of selected heavy metals in dumpsite soil compared with soil samples obtained from a green park area as a control. The research results were also related to threshold limits set by the National Environmental Standards and Regulations Enforcement Agency (NESREA), World Health Organization (WHO) and Food and Agriculture Organization (FAO). Soil samples were collected from a dumpsite inside Crown Estate (made up of residential quarters for both staff and students of Igbinedion University) and a green area of Igbinedion University's permanent site, Okada, Benin City, Edo State in Nigeria. The soil samples were air-dried, ground, sieved, digested and subjected to heavy metal analysis using atomic absorption spectroscopy. The analyzed metal profiles in the dumpsite soil samples are as follows: concentration of Fe, Pb, Cu, Zn, Mn and Ni ranged from 453.26 – 569.28, 0.85 – 1.16, 20.17 – 32.35, 60.98 – 74.26, 5.15 – 9.28, and 5.92 – 9.57 mg/Kg, with mean concentrations of 501.33 mg/Kg, 0.96 mg/Kg, 25.38 mg/Kg, 66.33 mg/Kg, 6.89mg/Kg and 7.90 mg/Kg respectfully, while the status of heavy metal concentration in soil samples collected from the control site ranged from 386.21 – 463.95, 0.82 – 1.32, 20.05 – 26.27, 47.75 – 65.22, 5.77 – 8.73, and 6.35 – 9.87 mg/Kg, with mean concentration of 401.76 mg/Kg, 1.05 mg/Kg, 23.05 mg/Kg, 54.84, 7.39 mg/Kg and 7.78 mg/Kg for Fe, Pb, Cu, Zn, Mn and Ni respectfully. Of all the metals analyzed only the level of Fe in this study did exceed the tolerance limits of NESREA, WHO and FAO. The results also revealed higher heavy metal content in the dumpsite justifiably due to the difference in anthropogenic activities carried out on the two sites.

Evaluation of lead tolerance and biosorption characteristics of fungi from dumpsite soils

Lead (Pb) pollution is a major concern in many developing nations of the world. Hence, there is a need for the development of an environmentally safe and cost-effective method for the clean-up of contaminated environments. The present study investigated the tolerance of presumptively identified fungal species isolated from 5 different dumpsite soils to Pb concentrations 200, 400, 600, 800, 1000, 1500, 5000, and 10000 mg/L. The identity of strains exhibiting outstanding tolerance was confirmed using molecular technique, and their biosorption capacity at 10000 mg/L was evaluated. FTIR and SEM analyses were performed on the Pb2+ untreated and treated fungal biomasses. A total of 17 fungal isolates belonging to the genera Aspergillus Alternaria, Chrysosporium, and Penicillium were obtained. All the fungi were resistant to the test concentrations of Pb2+ except Chrysosporium sp. (at 5000 mg/L and 10000 mg/L) and Alternaria sp. (at 1500 mg/L, 5000 mg/L, and 10000 mg/L). Four isolates molecularly identified as A. awamori OP341445 and OP341446 and A. niger OP342447 and OP341448 recorded outstanding tolerance (> 1). Biosorption capacity was at its peak on day 5 except in OP34148, day 10 with a value of 97.82 mg/g. The Pb2+ removal rate was at equilibrium on day 5 (≈86%) except for OP41447 and OP41448 (≈87%) on day 15. FTIR analysis reveals the involvement of functional groups O-H, C-H, N-H, O=C=O, C≡C, N=C=S, C=C, N-O, C-N, and S=O in the biosorption process. SEM showed distortion in the cellular structure of the fungi. These results indicated the lead remediation potential of the fungal strains.

Heavy Metal Concentration of Okra (Abelmoschus Esculentus) Grown on Dumpsite Soil in Benin City, Nigeria

The study investigates the concentrations of heavy metals in Okra (Abelmoschus esculentus) planted in dumpsite soil obtained from the University of Benin and Ekosodin in Benin City. Soil samples were collected before and after planting and analyzed for pH, total nitrogen (N), total organic carbon (C), phosphorus (P), iron (Fe), zinc (Zn), manganese (Mn), and heavy metal concentrations (Cu, Pb, Cd, and Cr). The study reveals variations in soil acidity levels across different locations before and after planting. In Table 1, soil pH was moderately acidic in Farmland (5.61), neutral in Market (6.79) and Residential (6.76) areas, and slightly acidic in Faculties (6.14). In Table 2, after planting, the pH remained moderately acidic in Market (5.68) and Residential (5.80), while becoming strongly acidic in Farmland (5.42) and Faculties (5.36). Total N and P decreased in most dumpsites after planting, while total organic carbon increased. Fe, Zn, and Mn concentration varied between dumpsites and after planting stages. Particle size distribution remained predominantly sandy across dumpsites and planting stages. The study suggests that Okra plants cultivated in various dumpsite soils showed no toxic levels for the selected heavy metals, with concentrations generally falling within acceptable limits for vegetable consumption. The copper concentration highest uptake observed in Okra plants from Residential Land (36.0 mg/kg) and the lowest in Farmland (23.3 mg/kg). Lead (Pb) uptake varied across dumpsites: Market (0.15 mg/kg), Farmland (0.10 mg/kg), Residential Land (0.12 mg/kg), and Faculties (0.06 mg/kg). Cadmium (Cd) uptake was observed at Market dumpsites (0.05 mg/kg), Farmland (0.02 mg/kg), Residential Area (0.01 mg/kg), and Faculties (0.04 mg/kg). Heavy metal concentrations in the soil and Okra plants were generally below the permissible limits set by the Department of Petroleum Resources (DPR) for soil and World Health Organization (WHO) for vegetables intended for human consumption.

Geochemistry and metagenomics analyses of bacterial community structure in selected waste dumpsites in Lagos Metropolis, Nigeria

Dumpsites are reservoirs of persistent organic pollutants (POPs) and heavy metals (HMs), constituting environmental hazards to humanity. Autochthonous microorganisms in dumpsites exhibit various degrees of responses to contaminants. Unfortunately, there is a dearth of information on the types and concentration of pollutants and the array of microorganisms in these dumpsites which may play important roles in the metabolism of such pollutants or other community processes. Therefore, determining the microbial community structure in such contaminated sites across a municipality is essential for profiling the taxa that would serve as consensus degraders of the pollutants. In this study, soil samples from three dumpsites (Cele, CS; Solous, SS; and Computer Village, CVS) were characterized for geochemical properties using GC-MS, MP-AES, and other analytical protocols, while the dynamics of bacterial communities were evaluated based on their 16S rRNA gene barcodes. A significant difference in the bacterial communities was observed among the dumpsites in relation to the extent of pollution caused by POPs and HMs. CVS, with the highest HM contamination, was rich in Actinobacteria (41.7%) and Acidobacteria (10.2%), in contrast to CS and SS. Proteobacteria (34.1%) and Firmicutes (20%) were the dominant phyla in CS (highest POP contamination), while Bacteroidetes (45.5%) and Proteobacteria (39.9%) were dominant in SS soil. Bacillus was the dominant genus in the most polluted dumpsite. Canonical correspondence analysis revealed that polycyclic aromatic hydrocarbons (PAHs) and HMs shaped the structure of the bacterial operational taxonomic units (OTUs) in the most polluted dumpsite. Out of a total of 706 OTUs, 628 OTUs exhibited a significant correlation (>50%) with benzo(b)fluoranthene, azobenzene, dibenzofurans, pyrene, dibenzo(a,l)pyrene, Cu, and Zn. In particular, Proteobacteria (Achromobacter sp. and Serratia sp.), Bacteroidetes (Zhouia sp.), and Firmicutes (Bacillus sp.) were suggested to be pivotal to the ecophysiology of dumpsite soils contaminated with POPs and HMs. The results generally underscored the importance of metagenomic and physicochemical analyses of polluted systems in enabling correlations for useful prediction of drivers of such ecosystems. This will further improve our understanding of the metabolic potential and adaptation of organisms in such systems.

ASSESSMENT OF HEAVY METAL POLLUTION IN SOIL AT A REFUSE DUMPSITE IN UNIVERSITY OF CROSS RIVER STATE (UNICROSS), CALABAR, SOUTH-SOUTH, NIGERIA

Total concentration and pollution indices of mercury (Hg), lead (Pb), chromium (Cr), cadmium (Cd), arsenic (As), nickel (Ni), and cobalt (Co) in dumpsite soil located in University of Cross River State, Calabar were evaluated in this work. Soil samples were collected at 0 - 15cm depth from two sampling stations at the dumpsite once in the months of April, August and December, 2021 and analyzed to the closest mg/kg using Atomic Absorption Spectrophotometer (AAS). The concentrations of the heavy metals showed that Cd>Pb>Ni>Cr>As>Co. All the concentrations of the heavy metals examined when compared with those of average value of heavy metals in shale showed that all the metals were lower than their corresponding world average value except Cd. Geoaccumulation index indicated unpolluted to moderately polluted for all metals studied except Cd which indicated strong to very strongly polluted. Contamination factor for Cd indicated very high contamination. Contamination degree for site 1 and 2 indicated considerable degree of contamination and moderate degree of contamination respectively. Pollution load index values investigated were within the baseline level for all the stations. The heavy metal pollution is attributable to the waste deposited at the dumpsite located in the institution. It is recommended that the dumpsite be relocated to another location that is far away from the residential area and from drinking water sources like boreholes.

Survey and Identification of Fungi Associated with Selected Dumpsite Soils in Lagos State, Nigeria

Survey and Identification of Fungi Associated with Selected Dumpsite Soils in Lagos State, Nigeria

Screening of Microorganisms Producing Polymer (PHB) from Dump Sites Soil in Ilorin Metropolis, Kwara State, Nigeria

This study was aimed at screening microorganisms isolated from dump sites for polymer production. Five samples of dump site soil were gathered from each of 10 distinct sites, totaling fifty samples, throughout the collection process. Microorganisms were isolated using the pour plate method. Bacteria isolates were identified using biochemical tests and molecular analysis using 16S rRNA gene primer while morphological characteristics are 18SrRNA gene primer were used to identify fungi isolate. Screening of the organisms for polymer production was done using Sudan Black Band Nile Blue A. The polymer extracted were analyzed using Fourier Transform Infrared Spectroscopy(FTIR) and Scanning Electron Microscope (SEM). Results revealed the presence of five fungi and seven bacterial species identified to be Aspergillus niger, Penicillium chrysogenum, Penicillium marneffei, Cladosporium tenuissimum and Rhizopus sp., while bacterial isolates were identified as Bacillus licheniformis, Bacillus cereus, Paenibacillus polymyxa, Bacillus megaterium, Bacillus mycoides, Bacillus subtillis and Enterobacter species. Only four bacterial isolates were positive for polymer production and molecularly identified as Bacillus subtilis strain AGB1 (OM273871), Bacillus megaterium strain AGB2 (OM216844), Paenibacillus polymyxa strain AGB3 (OM273889) and Bacillus licheniformis strain AGB4 (OP703543).The polymer has rough surfaces and crystalline in nature, while FTIR result indicated that the polymer had C=O carbonyl functional group and identified as polyhydrxybutyrate (PHB) polymer while SEM showed that it has crystalline surface. It can be concluded that bacterial isolates which were polymer producers can be utilized for large-scale production of polyhydroxybutyrate for industrial purposes

Deciphering the kinetics and pathway of lindane biodegradation by novel soil ascomycete fungi for its implication in bioremediation

Lindane, an organochlorine pesticide, negatively affects living beings and the ecosystem. In this study, the potential of 9 Ascomycetes fungi, isolated from an hexachlorocyclohexane dumpsite soil, was tested for biodegradation of lindane. The strain Pleurostoma richardsiae (FN5) showed lindane biodegradation rate constant (K value) of 0.144 d-1 and a half-life of 4.8d. The formation of intermediate metabolites upon lindane degradation including γ-pentachlorocyclohexene, 2,4-dichlorophenol, phenol, benzene, 1,3- cyclohexadiene, and benzoic acid detected by GC–MS and the potential pathway adopted by the novel fungal strain FN5 for lindane biodegradation has been elucidated. The study of gene profiles with reference to linA and linB in strain FN5 confirmed the same protein family with the reported heterologs from other fungal strains in the NCBI database. This study for the first time provides a thorough understanding of lindane biodegradation by a novel soil-borne Ascomycota fungal strain for its possible application in field-scale bioremediation.

Soil contamination by trace metals and assessment of the risks associated: the dumping site of Safi city (Northwest Morocco).

The main objective of this work was to determine the soil contamination with trace metals within and around the dumpsite of Safi city (Morocco) and to evaluate the potential environmental risk associated. The results showed that the average soil concentrations of trace metals had the following order: Fe > Zn > Cu > Cr > Cd and exceeded the world and the upper continental background concentrations except for Fe. In addition, the concentrations of Zn, Cu, and Cd remained beyond the limit standards given by the WHO/FAO. Geoaccumulation index, enrichment factor, and pollution load index (PLI) indicated that the dumpsite soil is highly contaminated and deteriorated, presenting evidence of high ecological risk proved by the values of the potential ecological risk index (PERI). Correlation analyses revealed a strong relationship between the organic matter & [Fe, Zn, Cr, Cd], calcium carbonates & [Zn, Cr], and Cr & Cu inside the dumpsite soil. Principal component analysis confirmed the temporal and spatial classification of Zone A as the oldest and Zone C as the youngest and indicated that the regrouped trace metals could have the same behavior and or the same origin. The interpolation of trace metals concentrations and PERI revealed a plausible extension outside the landfill, confirmed by PLI values.

Degradation of LDPE Using the Winogradsky Column Containing Otteri Dumpsite Soil: Prediction of Mechanism and Metabolites Determination

Background of the Research: Plastic pollution has taken over the world. Toxicity of the plastics and other pollutants is enhanced due to the formation of microplastics and nano-plastics that attract Persistent Organic Pollutants (POPs). The need for the treatment of plastic waste in the current scenario led to the rise of various treatment processes. Biodegradation, an eco-friendly approach to eliminate plastics urged to discover plastic-utilizing bacteria and plastic-eating worms. Bacterial degradation of plastics has been extensively studied utilizing the entire microbial community. Hence, the current research focuses on the biodegradation of Low-Density polyethylene (LDPE) using Winogradsky Column constructed using dump yard soil. LDPE degradation was determined using FTIR and GC-MS analysis, which is used to analyze the degradation mechanism of LDPE. Methods: Sample Collection and Column Construction: The soil samples collected from the Chennai dump yard were used to construct Winogradsky columns. The column with LDPE and enrichment sources is used to study LDPE degradation. Analysis of LDPE Degradation: The LDPE sheet after incubation was washed with surfactant and ethanol. The dried sheet was analyzed for weight loss and the metabolites were identified using GC-MS analysis. The GC-MS chromatogram was used to determine the pattern of degradation by the microbial community in the dump yard soil. Results: The mass spectral analysis of GC peaks has been carried out using the electron ionization method, and ions were detected using positive ions scanning mode. The GC peaks appeared at 22.532 and 23.117 min in the control LDPE sheet, which was found to be nonadecane and octacosane, whereas, in the treated LDPE sheet, the GC peaks appeared at 22.467 and 23.062 min. The fragmentation pattern indicates the loss of m/z 14, which confirms the loss of methylene (-CH2-) fragments in alkyl chains. The difference in retention time could be correlated with the increase of CH2 in the alkyl chain length and molecular weight. Higher molecular weight alkanes, such as C16, C18, and C20 above appeared at higher retention times. The presence of longer alkyl chains indicates the LDPE polymer chains. The treated LDPE sample has been analyzed, and the fragmentation pattern indicates the presence of aliphatic chains of C16 or C18. Conclusion: The current study provides an efficient method to utilize the microbial community as a whole to degrade LDPE. The degradation mechanism of LDPE was determined using GC-MS analysis. The high molecular weight polymeric chain was degraded to small chains, and the formation of alcohol indicates the occurrence of terminal oxidation. Hence, this confirms the degradation of LDPE by the microbiome present in the dump yard soil.

Assessment of soil and water quality nearby region of solid waste dumpsite

Assessment of soil and water quality nearby region of solid waste dumpsite

Production of Cellulase by Trichoderma viride via Submerged Fermentation using Corncob as Substrate

Cellulolytic enzymes are commonly used in lignocellulosic biomass conversion, textile, and paper and pulp industries. However, the high cost of cellulase and the high demand has led to increase researches to explore agro-residues for cost-effective production. This study was aimed at isolating Trichoderma viride from decaying wood and soil, and testing the isolates for cellulase production via submerged fermentation using corncob as substrate. Twenty-one (21) soil samples were collected from three different locations (botanical garden, refuse dump site and decaying wood) and used in the study. Colonies suspected to be Trichoderma viride were identified by microscopy of lactophenol cotton blue-stained preparation and slide culture technique, respectively. Isolates confirmed to be Trichoderma viride were then screened for cellulase production on a mineral salt medium containing carboxymethyl cellulose as an inducer. The isolates were further tested for cellulase production using corncob as the substrate via submerged fermentation. Out of the 21 samples analysed, 4 (19%) were positive for Trichoderma viride based on cultural and microscopic characteristics. The highest occurrence of Trichoderma viride (57%) was recorded from decaying wood samples, while no occurrence (0%) was observed from the botanical garden and refuse dumpsite soils. All four isolates obtained produced cellulase, with T. viride DW6 having the highest zone of cellulose hydrolysis (61.5 ± 2.12 mm) and T. viride DW1 having the least (58.5 ± 2.12 mm). The highest enzyme activity was recorded from T. viride DW4 (3.41 ± 0.46 U/ml) and the lowest from T. viride DW1 (1.77 ± 0.52 U/ml) using corncob as substrate. Trichoderma viride is abundantly present in decaying wood, and such isolates have high cellulase-producing ability, as wood material is rich in cellulose. This preliminary study provides information on the isolation of T. viride from decaying wood and their potential for cellulase production using corncob as substrate.

Evaluating the microcystin-LR-degrading potential of bacteria growing in extreme and polluted environments

Inhabitants of extreme and polluted environments are attractive as candidates for environmental bioremediation. Bacteria growing in oil refinery effluents, tannery dumpsite soils, car wash effluents, salt pans and hot springs were screened for microcystin-LR biodegradation potentials. Using a colorimetric BIOLOG MT2 assay; Arthrobacter sp. B105, Arthrobacter junii, Plantibacter sp. PDD-56b-14, Acinetobacter sp. DUT-2, Salinivibrio sp. YH4, Bacillus sp., Bacillus thuringiensis and Lysinibacillus boronitolerans could grow in the presence of microcystin-LR at 1, 10 and 100 µg L−1. Most bacteria grew optimally at 10 µg L−1 microcystin-LR under alkaline pH (8 and 9). The ability of these bacteria to use MC-LR as a growth substrate depicts their ability to metabolize the toxin, which is equivalent to its degradation. Through PCR screening, these bacteria were shown to lack the mlr genes implying possible use of a unique microcystin-LR degradation pathway. The study highlights the wide environmental and taxonomic distribution of microcystin-LR degraders.

Pectinase production by fungal-based solid-state fermentation of selected agricultural wastes

Agricultural waste is the residues from growing and processing raw agricultural products. They can be properly managed using fungi to produce economical materials such as pectinase enzymes that act as biological agents which are applicable in many areas. This research was aimed at producing pectinase by fungal-based solid-state fermentation of agricultural wastes. Fungi were isolated from dump sites soil using the pour plate method. These fungal isolates were inoculated into the pretreated agricultural waste, including watermelon, mango, and pineapple peels. The degradation period was 15 days on mineral salt solid media using separate flasks for each waste and fungus. They were incubated at room temperature (28°C). The pectinase was assayed using pectin and DNSA (dinitrosalicyclic acid). Fungal isolates were identified and screened for pectinase production using standard methods. The pH and temperature were optimized to study the effect on pectinase activities using standard procedures and pectinase was purified using column sephadex G-100. Molecular identifications were carried out on the isolates using 18srRNA gene primers. The fungi were identified as Aspergillus niger strain AGF3 (OM273994), Penicillium Chrysogenum strain AGF2 (OM273982) and Cladosporium tenuissimum strain AGF1 (OM273981). Aspergillus niger strain AGF3 (OM273994) produced the highest specific pectinase activities in mango waste (2400 U/mg. protein/ mL and it can be compared to what was produced by Cladosporium tenuissimum strain AGF1 (OM273981) (1590 U/mg. protein/mL). High specific pecrtinase activity was also obtained from pineapple peels (2200 U/mg. protein/mL) produced by Cladosporium tenussimum strain AGF1 (OM273981). It can be concluded in this study that Aspergillus niger strain AGF3 (OM273994) and Cladosporium tenuissimum strain AGF1 (OM273981) were the best producers of pectinase using mango and pineapple peels, while Penicillium chrysogenum strain AGF2 (OM273982) produced substantial pectinase in all the three agricultural wastes but not at higher levels.

Mathematical modeling and numerical simulation technique for selected heavy metal transport in MSW dumpsite

The study focused on development of mathematical modeling and numerical simulation technique for selected heavy metal transport in Uyo municipal solid waste dumpsite in Akwa Ibom State to investigate the level in depth to which leachate from the dumpsite extends and the quantity of leachate at various depth of the dumpsite soil. Uyo waste dumpsite is operating open dumping system where provisions are not made for preservation and conservation of soil and water quality, hence, the need for this study. Three monitoring pits within Uyo waste dumpsite were constructed and infiltration runs were measured, and soil samples were collected beside infiltration points from nine designated depths ranging from 0 to 0.9 m for modeling heavy metal transport in the soil. Data collected were subjected to descriptive and inferential statistics while the COMSOL Multiphysics software 6.0 was used to simulate the movement of pollutants in the soil. It was observed that heavy metal contaminant transport in soil of the study area is in the power functional form. The transport of heavy metals in the dumpsite can be described by a power model from linear regression and a numerical model based on finite element. Their validation equations showed that the predicted and the observed concentrations yielded a very high R2 value of over 95%. The power model and the COMSOL finite element model show very strong correlation for all selected heavy metals. Findings from the study has identified level in depth to which leachate from the dumpsite extends and the quantity of leachate at various depth of the dumpsite soil which can be accurately predicted using leachate transport model of this study.

Geophysical and geochemical study of the contaminant impact of Oke-Tage solid waste dumpsite, Southwestern Nigeria

The physicochemical properties of groundwater, geochemical characteristics and subsurface formation of the Oke-Tage waste dumpsite soil material were assessed to determine the impact of the leachate generated from the waste dumpsite on the quality of the groundwater within the study area. Water samples collected from hand-dug wells were analyzed to determine groundwater quality, while soil samples were examined for their geochemical characteristics. Ten Vertical Electrical Sounding (VES) surveys were carried out with an electrode spacing (AB/2) increasing from 1 to 200 m. Also, four 2D electrical resistivity profilings were done using the dipole–dipole configuration. The hydro-chemical analysis showed an elevated Cadmium (Cd) and Lead (Pb) concentration above the maximum permissible limits. The physicochemical results indicated that the Electrical Conductivity (EC) ranged from 1900 to 3670 µS/m, while Total Dissolved Solid (TDS) ranged from 585 to 620 mg/L. The health risk assessment showed no significant health risks associated with exposure to the metals due to HI values less than 1. Based on the VES result, four geoelectric layers comprising topsoil, weathered layer, fractured basement, and fresh basement were identified. The 2D resistivity structures revealed that the topsoil and weathered layers practically merged and are characterized by relatively low resistivity (< 30 Ωm) beneath the dump site. The study concluded that the groundwater and soil in the vicinity of the investigated Oke-Tage waste dumpsite had been negatively impacted to levels that called for caution especially using the water for regular potability purposes.

Effect of Leachate on Soil in Jos Metropolis, Plateau State Nigeria

Effect leachate on soil quality in Jos is expected because the disposal sites continues to be the major route of infiltration as it affects quality of the area. Six selected disposal sites soil and normal soil were collected local auger at depth range of 1.5 and 3.0 m with distances of 1.0, 1.5,3.0m. The study aim identifies the effect, using PAST statistical software and excel to analyze the results. Particle size of sand has higher percentage with increase porosity from surface to subsurface (surface range 39.54-73.22, subsurface 40.72-73.50). Moisture contents increase from surface to subsurface. Specific gravity decreases from surface to subsurface (surface range 2.58-2.65, subsurface 2.15-2.44). Shear strength result shows increase to subsurface (surface range 15.65-17.43, subsurface 16.34-18.30). Compressibility test result shows slight increase from surface to subsurface. Permeability result show increase from surface to subsurface. Physical characteristics of pH indicate values that are alkaline in nature (surface range 7.2-9.4 subsurface 6.2-8.5). TDS decrease from surface to subsurface (range 143-640, 187-584).EC increase slightly from surface to subsurface (surface range 164-919, subsurface 184-915). Anions result shows chloride have higher concentration at surface (surface range 100-380, subsurface 96-360) while sulphate also have higher concentration on surface than subsurface (surface range 192-270, subsurface 178-225). Cation results shows sodium ion concentration on the surface increase to subsurface (surface range 250-2600, subsurface 265-2705). Potassium concentration also increase on the surface to the subsurface (surface range 172-243, subsurface 186-253) while magnesium ion also increases from surface to subsurface (surface range 3.0-4.4, subsurface 3.7-4.8) and calcium ion shows normal range from surface to subsurface (surface range 10000-12000, subsurface 10000-130000). The heavy metals concentration in the dumpsites soil shows higher values (Ba, Ce, La, Rb, Cr, Th and Fe) in both surface and subsurface above normal soil.

Heavy metal co-resistance with antibiotics amongst bacteria isolates from an open dumpsite soil

Heavy metal co-resistance with antibiotics appears to be synergistic in bacterial isolates via similar mechanisms. This synergy has the potential to amplify antibiotics resistance genes in the environment which can be transferred into clinical settings. The aim of this study was to assess the co-resistance of heavy metals with antibiotics in bacteria from dumpsite in addition to physicochemical analysis. Sample collection, physicochemical analysis, and enumeration of total heterotrophic bacteria counts (THBC) were all carried out using standard existing protocols. Identified bacteria isolates were subjected to antibiotics sensitivity test using the Kirby Bauer disc diffusion technique and the resulting multidrug resistant (MDR) isolates were subjected to heavy metal tolerance test using agar dilution technique with increasing concentrations (50, 100, 150, 200 and to 250 μg/ml) of our study heavy metals. THBC ranged from 6.68 to 7.92 × 105 cfu/g. Out of the 20 isolates subjected to antibiotics sensitivity, 50% (n = 10) showed multiple drug resistance and these were B. subtilis, B. cereus, C. freundii, P. aeruginosa, Enterobacter sp, and E. coli (n = 5). At the lowest concentration (50 μg/ml), all the MDR isolates tolerated all the heavy metals, but at 250 μg/ml, apart from cadmium and lead, all test isolates were 100% sensitive to chromium, vanadium and cobalt. The control isolate was only resistant to cobalt and chromium at 50 μg/ml, but sensitive to other heavy metals at all concentrations The level of co-resistance shown by these isolates is a call for concern.