A novel biomethane (BMP) and composting (CMP) potential framework for determining biogas and composting potential of urban organic waste.

Without treatment, urban market-generated organic waste is discarded in landfills. This could cause environmental contamination due to leachate. This study aims to develop a novel bio-methane and composting potential framework for evaluating the biogas and compostability of organic waste from the Bantama market in Kumasi. Using novel dashboards, the bio-methane and composting potentials were evaluated, and the Theoretical Biomethane Potential (TBMP) was reported to be between 331.52 and 457.93 l CH4/kg VS for carrot leaves and banana peels, respectively, assuming a biodegradability of 80% for the substrates. Only one of the four conditions for compostability was met by the substrates, indicating that they are not suitable for direct composting. In order to optimize the potential of the waste, an integrated system of anaerobic digestion (AD) and composting was utilized. The proposed plant was profitable since the payback period was less than two years, the Net Present Value (NPV) was greater than one, and the Benefit Cost Ratio (BCR) was greater than one. The anaerobic digester and composting plant are capable of producing 12269392 kWh of electricity and 19585 kg of compost per year, respectively. Lastly, the AD and composting technologies at the Bantama market are cost-effective. The government and municipalities may therefore assist private investors in constructing a waste processing plant.

Ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana.

There is a growing recognition that activities at automobile mechanic shops could contribute to heavy metal contamination of soils. This study seeks to evaluate the ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana. Herein, 20 composite soil samples were taken, acid-digested, and the concentrations of Cu, Pb, Cd, Mn, Ni, Cr, and Fe were measured using a flame atomic adsorption spectrometer (SHIMADZU, AA 7000). Appraising metal pollution indices, the potential human and ecological risks associated with analyzed metals were carried out. Findings of the present study indicate that the levels of analyzed metals of soils exceeded the control soil sample and the European Union standards for soil quality. The mean metal concentration increased in the order Fe > Mn > Cu > Ni > Pb > Cr > Cd in the soils. Outcomes of enrichment factor, geo-accumulation index, and contamination factor revealed that the soil quality is deteriorated with Cu, Pb, and Cd. The potential ecological risk identified Cd and Pb as the richest elements and offered a high ecological risk in all sampling sites. Furthermore, hazard quotient of analyzed metals depicted that Ni and Mn in urban soils of Bogoso Junction automobile mechanic shops may pose a threat to children (HI > 1). Dermal contact and inhalation of soil particles are the main exposure routes for children susceptibility. Specifically, cancer risk associated with Cd inhalation was 10 times greater than oral ingestion of Pb, showing a relatively high carcinogenic hazard to humans. Altogether, artisanal activities such as engine repair, welding and soldering, vehicle overhauling, and oil exchange at the automobile mechanic shops could deteriorate the soil quality resulting in ecological and human health implications within the vicinity of automobile mechanic shops in Ghana.

Spatial distribution and eco-environmental risk assessment of heavy metals in surface sediments from a crater lake (Bosomtwe/Bosumtwi).

Thirty samples of sediments were taken from Bosumtwi Lake (also called Bosomtwe Lake) in Ghana and analyzed for the contents of Fe, As, Hg, Co, Cr, Ni, Cd, and Pb. Several pollution indices (enrichment factor (EF), contamination factor (CF), geoaccumulation (Igeo), and pollution load index (PLI)) were used to determine sedimentary pollution levels, and the risk of environmental exposure was calculated using Hakanson's potential ecological risk (PER) indices. The results from PER assessments have indicated that sediments from the Bosumtwi Lake present a moderate environmental risk. According to EF calculations, Hg in Bosumtwi lake sediments is the element of concern that is being severely enriched. Hg was the largest contributor to PER with a 97% risk contribution. Multivariate statistical analysis revealed that the main sources of Hg were agrochemicals and atmospheric deposition, whereas the sources of Fe, As, Co, Cr, and Ni to Bosumtwi Lake were natural processes and are derived from the local lithology. There was no strong significant correlation among the contents of the heavy metals, sediment grain sizes, and total organic carbon (TOC), suggesting their lack of control in the distribution of heavy metals, the source, and the transport pathway. Finally, it is strongly recommended to do a study on Hg bioavailability in Bosumtwi Lake sediments. These findings will be relevant to Bosumtwi Lake's profiling and historical development of heavy metal loads.

Cancer and non-cancer risks in humans exposed to trace elements in drinking water from a crater lake (Bosumtwi/Bosomtwe).

The total and dissolved lead, cadmium, mercury, nickel, chromium, cobalt, and arsenic in 30 water samples collected from Bosomtwe Lake were analyzed. Arsenic bioavailability was also determined using the ARSOlux test system. Except for chromium, their mean values in the study results exceeded the WHO permissible limit for potability. Cancer and non-cancer effects associated with exposure to dissolved and total metals by a child and an adult via oral and dermal routes were estimated. The hazard quotient (HQ) values obtained (except adult exposure to total arsenic of 1.71 × 1000 ) were less than unity. Between child and adult, the recorded hazard index (HI) was 0.82 and 1.75, respectively. The HI results indicate that the adult population is at risk for non-cancer health effects. Arsenic was the element of concern, and it remained biologically available for uptake by target groups. For child and adult, respectively, arsenic contributed 96.39% and 97.29% to HI values. The risk values for cancer in a child and an adult with oral and dermal exposure to dissolved and total arsenic were lower than the USEPA range. Principal component and cluster analysis identified atmospheric deposition, geogenic, and unregulated application of agrochemicals as plausible sources of water pollution in Bosomtwe Lake. PRACTITIONER POINTS: The hazard quotient (HQ) values obtained for adult exposure to total arsenic was 1.71 × 1000 . Arsenic remained biologically available for uptake by target groups. The calculated health index (HI) indicated that the adult population is at risk for non-cancer health effects. Arsenic contributed 96.39% and 97.29% to HI values for a child and an adult. Atmospheric deposition, geogenic, and unregulated application of agrochemicals were the plausible sources of water pollution in Bosomtwe Lake.