Assessing soil pollution from a municipal waste dump in Islamabad, Pakistan: a study by INAA and AAS

Role of microbes in bioaccumulation of heavy metals in municipal solid waste: Impacts on plant and human being

The presence of heavy metals in municipal solid waste (MSW) is considered as prevalent global pollutants that cause serious risks to the environment and living organisms. Due to industrial and anthropogenic activities, the accumulation of heavy metals in the environmental matrices is increasing alarmingly. MSW causes several adverse environmental impacts, including greenhouse gas (GHG) emissions, river plastic accumulation, and other environmental pollution. Indigenous microorganisms (Pseudomonas, Flavobacterium, Bacillus, Nitrosomonas, etc.) with the help of new pathways and metabolic channels can offer the potential approaches for the treatment of pollutants. Microorganisms, that exhibit the ability of bioaccumulation and sequestration of metal ions in their intracellular spaces, can be utilized further for the cellular processes like enzyme signaling, catalysis, stabilizing charges on biomolecules, etc. Microbiological techniques for the treatment and remediation of heavy metals provide a new prospects for MSW management. This review provides the key insights on profiling of heavy metals in MSW, tolerance of microorganisms, and application of indigenous microorganisms in bioremediation. The literatures revealed that indigenous microbes can be exploited as potential agents for bioremediation.

Strategies for reducing greenhouse gas emissions from municipal solid waste management in Pakistan

The studies on municipal solid waste (MSW) management in Pakistan and its impacts on greenhouse gas (GHG) emissions are glaringly missing. Therefore, this study examines the effect of MSW management on GHG emissions in Pakistan and suggests the best suitable strategies for alleviating GHG emissions. The Intergovernmental Panel on Climate Change (IPCC) 2006 waste model (WM) was used to create inventory of GHG emissions from landfilling. The solid waste management GHG (SWM-GHG) calculator and strengths-weaknesses-opportunities-threat (SWOT) analyses were used as strategic planning tools to reduce GHG emissions by improving MSW management in Pakistan. The IPCC 2006 WM estimated 14,987,113 metric tonnes (Mt) carbon dioxide equivalents (CO₂-eq) of GHG emissions in 2016. The SWM-GHG calculator, on the other hand, estimated 23,319,370 Mt CO_2-eq of GHG emissions from management of 30,764,000 Mt of MSW in 2016, which included 8% recycling, 2% composting, and 90% disposal in open dumps. To reduce GHG emissions, two strategies including recycling-focused and incineration-focused were analysed. The recycling approach can reduce more GHG emissions than incineration, as it can reduce 36% of GHG emissions (as compared to GHG emission in 2016) by recycling 23% of MSW, anaerobically digesting 10% of MSW, and disposing of 67% of MSW in sanitary landfills (with energy recovery). Moreover, the SWOT analysis suggested integration of the informal sector, adoption of anaerobic digestion and formulation of explicit MSW regulations for improving the current management of MSW which will also result in lower GHG emissions.

Immobilization possibility of tannery wastewater contaminants in the tiles fixing mortars for eco-friendly land disposal

The Hazaribagh tannery area of Bangladesh is currently facing an enormous problem regarding the harmful impacts of wastewater produced from leather industries on the surrounding environment due to the presence of contaminants at a toxic level. As such, the current study aims to analyze the entrapment of tannery wastewater's pollutants inside the mortar specimens for sustainability. Two types of binding agents such as Portland Composite Cement (PCC) and Ready Mixed Dry Mortar (RMDM) were employed to prepare separate mortar pastes in which the collected tannery wastewater was used as mixing liquid. Also, five types of samples including brick walls made with only the PCC, where tiles walls and blocks constructed with both types of binding agents were built. Analytical results show that the surrogate contaminated water mixed mortar blocks possessed about 6-14% lower compressive strength than that of the blocks prepared with drinking water. Moreover, the examined heavy metals were observed below the limit of detection in the curing liquid of studied tiles walls during the whole test protocol of 360 days period. The explicit outcomes of this study might be a promising solution to minimize the effects of tannery wastewater contaminants on the environment by utilizing this wastewater as a mixing component in the tiles fixing mortar of walls and floors.

Evaluation of Heavy Metal Pollution in the Suame Industrial Area, Kumasi, Ghana

BACKGROUND

Heavy metal pollution in industrial and residential areas in cities has become a public health issue in Ghana. Anecdotal evidence suggests that most industrial areas have elevated levels of heavy metals in soil. As a result of poor zoning and unregulated activities, large sections of seemingly industrial areas are also used as residential areas. There have been no studies on the levels of heavy metal contamination in such mixed activity locations.

OBJECTIVES

The study was undertaken to identify possible heavy metals and their concentrations in soil samples collected from the Suame Industrial Area, Kumasi, Ghana.

METHODS

Soil samples were collected, processed and the concentration of copper (Cu), lead (Pb), zinc (Zn), cobalt (Co) and chromium (Cr) were analyzed using X-ray fluorescence (XRF).

RESULTS

The concentration of all metals exceeded the threshold limit values (TLV). They also exceeded the European Soil Bureau Network (ESBN) maximum allowable limits (MAL), and are therefore considered to be pollutants. The results, expressed as mean concentration±standard deviation mg/kg (percent above TLV) were Pb: 414.83±159.38 mg/kg (418.9%), Cr: 264.84±189.15 mg/kg (353.1%), Co: 68.15±34.12 mg/kg (227.2%), Cu: 265.82±80.53 mg/kg (354.4%) and Zn: 3,215.84±4,074.54 mg/kg (1,607.9%). Furthermore, the concentrations of Pb and Co exceeded the United States Environmental Protection Agency (USEPA) residential soil regional screening levels (RSLs).

CONCLUSIONS

The elevated metal concentrations found in the present study demonstrate that the site is heavily polluted with Pb, Co and Cr. This is attributed to unregulated activities at the site; therefore, measures should be put in place to ameliorate the effects of potential heavy metal toxicity to workers, local residents and the environment. Re-zoning of activities and clear demarcation of residential and industrial areas is advocated.

Heavy element accumulation in Evernia prunastri lichen transplants around a municipal solid waste landfill in central Italy

This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements.

TXRF analysis of soils and sediments to assess environmental contamination

Total reflection x-ray fluorescence spectroscopy (TXRF) is proposed for the elemental chemical analysis of crustal environmental samples, such as sediments and soils. A comparative study of TXRF with respect to flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy was performed. Microwave acid digestion and suspension preparation methods are evaluated. A good agreement was found among the results obtained with different spectroscopic techniques and sample preparation methods for Cr, Mn, Fe, Ni, Cu, and Zn. We demonstrated that TXRF is suitable for the assessment of environmental contamination phenomena, even if the errors for Pb, As, V, and Ba are ingent.

Instrumental neutron activation analysis for the study of size-fractionated airborne particulate matter samples

In order to devise methodology to study various environmental matrices 28 pairs of coarse and fine air particulate samples were collected in the vicinity of an automotive workshop located at Tasmasipabad on Chaklala Road, Rawalpindi. The samples were collected using a Gent sampler and polycarbonate filters during the period 7 to 27 April 2009. These samples were analyzed using instrumental neutron activation analysis (INAA) using the low power Pakistan Atomic Research Reactor-2 (PARR-2). Reference materials (RMs) IAEA-SL1 and IAEA-S7 were used for calibration and quality assurance (QA) purpose. The gravimetric data for these samples were found to exceed the PM2.5 and PM10 national limits. Up to 34 elements were measured using the INAA optimized procedure.

Assessment of metal pollution in soils from a former Havana (Cuba) solid waste open dump

Concentrations of cobalt, nickel, cooper, zinc and lead in the top-soils (0-10 cm) from a former Havana solid waste open dump were estimated by X-ray fluorescence analysis. The mean metal contents in the dump topsoil samples (in mg kg(-1): 8.4 ± 2.7 for cobalt, 50 ± 27 for nickel, 252 ± 80 for copper, 489 ± 230 for zinc and 276 ± 140 for lead) were compared with mean concentrations from Havana urban soils and from other solid waste disposals around the world. The comparison with Dutch soil quality guidelines showed a serious cooper contamination and a slight contamination with the rest of determined metals. The values of the integrated pollution index (mean index = 3.5) indicated that dump soils are highly contaminated by metals, and the enrichment index values shows that metal concentrations on the studied locations are above the permissible levels for urban agriculture.

Assessment of heavy metal toxicants in the roadside soil along the N-5, National Highway, Pakistan

The assessment of the toxicants in roadside soil on regular basis has become extremely essential with the increase in awareness for the metal toxicity in the environment. The present study investigates the presence of toxic metals along National Highway (N-5), Pakistan. Averages of about 1.3 million per month of automobile vehicles ply on this route. Lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), cobalt (Co), manganese (Mn), mercury (Hg), and iron (Fe) were analyzed by atomic absorption spectrophotometry in roadside soil at the nine selected locations along the highway. Strong Pearson correlations (α = 0.05) were found between Pb and Zn (r(2) = 0.887), Fe and Mn (r(2) = 0.880), Hg and Cd (0.864), Cu and Zn (0.838), and Cu and Pb (0.814). The correlation between the elemental compositions of the main automobile components revealed vehicular traffic as the main non-point source of roadside soil pollution. Extremely high level of mercury, 144.05 mg kg(-1), was found at S5. It was revealed that the unregulated incineration and dumping sites of hazardous waste material along N-5 were also responsible for these contaminations. Multivariate analysis on the obtained data also disclosed the same interpretation. Cluster analysis of the data grouped Pb, Zn, and Cu at 85.23% similarity, whereas, Cd, Hg, and Ni were grouped at 78.75% similarity basis. The findings need swift action against the root cause of soil pollution.