Journal of Global Ecology and Environment

Used Lead-Acid Batteries from Nigeria's Off-Grid Solar Sector: Environmental Health Risks, Regulatory Gaps and Circular-Economy Responses

George-Oloja Nkechinyere — 2026-10-01

Background: Nigeria’s rapid expansion of off-grid solar systems is increasing the use and eventual disposal of lead-acid batteries, yet the contribution of solar-derived batteries to the country’s wider used lead-acid battery waste stream remains poorly quantified.

Aim: This narrative review examined the management of used lead-acid batteries from Nigeria’s off-grid solar sector, associated environmental and public-health risks, regulatory gaps, and circular-economy responses.

Methodology: MEDLINE, Scopus, the Cochrane Library and Google Scholar were searched from inception to August 2026, together with relevant institutional and Nigerian government sources. Evidence was categorised as Nigerian solar-battery evidence, Nigerian lead-acid battery evidence of unspecified origin, evidence from other African settings, or general lead toxicology.

Results: No identified Nigerian study directly attributed measured lead exposure or contamination to batteries originating from off-grid solar systems. However, evidence from the wider Nigerian battery-recycling stream shows substantial occupational and environmental hazards. Informal recycling workers had a mean blood lead level of 40.17 µg/dL compared with 3.61 µg/dL among controls, while soil lead concentrations reached 29,000 ppm outside recycling facilities. Nigeria has battery regulations and an extended producer-responsibility framework, but important implementation gaps remain in enforcement, traceability, institutional coordination and informal-sector oversight.

Conclusion: The downstream environmental and health burden attributable specifically to off-grid solar batteries remains unquantified. Source-level traceability at collection is therefore necessary to distinguish solar batteries within the wider waste stream and support sector-specific accountability.

Chemical Engineering Strategies for Wastewater Treatment in Agro-industries

S. Lakshmi — 2026-10-08

Agro-industries, including sugar and distillery complexes, dairies, palm and olive oil mills, starch and tapioca units, breweries, slaughterhouses, poultry processors and fruit and vegetable canneries, generate effluents that are seasonal, hydraulically erratic and extraordinarily concentrated, with chemical oxygen demand (COD) frequently between 2,000 and 200,000 mg L^-1 and nutrient loads far above those of municipal sewage. Conventional end-of-pipe disposal wastes both water and the nitrogen, phosphorus and potassium these streams carry, while land application of untreated effluent degrades soil structure, salinises the root zone and depresses crop performance. This review organises the treatment of agro-industrial wastewater as a sequence of chemical engineering unit operations rather than a catalogue of technologies. Effluent characteristics are first compiled by sector and translated into design-relevant descriptors - COD/BOD5 ratio, C:N:P stoichiometry, alkalinity, suspended and colloidal fractions, oil and grease, phenolics, colour and salinity - that determine process selection. Preliminary and physicochemical operations (equalisation, coagulation–flocculation, dissolved air flotation, chemical precipitation), biological reactor engineering (activated sludge and its sequencing-batch and attached-growth variants; upflow anaerobic sludge blanket, expanded granular sludge bed and anaerobic membrane bioreactors), advanced oxidation and electrochemical processes, adsorption on agro-residue-derived biochar, and pressure- and osmotically driven membrane separations are each examined in terms of governing kinetics, mass-transfer limitations, loading rates, energy demand and residual management. Particular attention is given to resource recovery - biomethane, struvite, ammonia, volatile fatty acids, polyphenols and reclaimed water - and to the agronomic quality of reclaimed effluent, evaluated through electrical conductivity, sodium adsorption ratio, residual sodium carbonate, trace-element burden and pathogen indicators. The review argues that no single unit operation is adequate for these matrices and that robust performance comes from deliberately sequenced trains in which an anaerobic bioreactor handles the bulk organic load and energy recovery, a polishing step addresses recalcitrant colour and micropollutants, and a nutrient-recovery loop diverts N and P to a fertiliser product rather than to a receiving water. Optimisation approaches (response surface methodology, artificial neural networks, life-cycle and techno-economic assessment) and the principal barriers to adoption in small and medium-sized agro-enterprises are discussed, and research priorities are identified for low-energy, low-sludge, recovery-oriented process trains suited to tropical and subtropical agricultural economies.

Impacts of Water Hyacinth on Aquatic Ecosystems and Its Management

Archana Kashyap — 2026-10-17

Water hyacinth is simultaneously an invasive ecosystem engineer, a symptom of catchment degradation and a potential source of recoverable biomass. These overlapping roles complicate assessments that equate plant presence with ecological damage or visible clearance with restoration. This critical narrative review examines the mechanisms, context dependence and management implications of water hyacinth invasion across freshwater lakes, reservoirs, wetlands and slow-flowing channels. Targeted scholarly searching and citation tracing identified research published through 31 July 2026, with evidence appraised according to study design, environmental comparability, outcome measurement and duration. The synthesis connects invasion ecology, water quality, biodiversity, human exposure, biological control and biomass processing rather than ranking interventions solely by short-term plant suppression. The most consistent evidence concerns shading, oxygen depletion under extensive persistent mats, obstruction of water-dependent activities and changes in habitat composition. Nutrient concentrations, fish assemblages, disease-transmission potential and greenhouse-gas fluxes show more conditional responses. Contradictory findings frequently reflect differences in hydrological exchange, reference habitat, plant rooting, decomposition and measurement scale. Physical removal can rapidly restore access and export nutrients, but recurrence remains likely where propagules and favourable growth conditions persist. Biological control can provide substantial suppression, including in nutrient-rich reservoirs, although agent establishment, seasonal population recovery and sustained delivery determine performance. Herbicides and microbial products require formulation-specific assessment and cannot be judged safe from plant mortality or basic water chemistry alone. Biomass utilisation offers complementary disposal and resource-recovery pathways, but laboratory yields do not establish commercial viability, contaminant safety or landscape-scale control. A defensible management strategy separates immediate hazard reduction, sustained suppression and ecological recovery, linking each objective to appropriate monitoring. Priorities include replicated long-term intervention studies, whole-system nutrient and greenhouse-gas accounting, independent economic evaluation and participatory assessment of who benefits from control. Durable management depends on matching interventions to ecological processes and institutional capacity rather than treating water hyacinth as either an unqualified menace or an inherently sustainable resource.

Grain-Size Analysis of Sandy Sediments from the Substratum of Banco Bay, Abidjan, Lower Côte d’Ivoire

Diby Ferdinand Yao — 2026-09-18

Banco Bay, within the Ebrié Lagoon system of southern Côte d’Ivoire, contains sandy substratum deposits whose sedimentological characteristics remain insufficiently documented. While previous studies have largely focused on superficial lagoonal sediments and present-day sedimentary dynamics, limited information is available on the grain-size properties of the sandy deposits forming the bay’s substratum. Characterising these deposits is therefore important for improving understanding of their sedimentary features and depositional conditions. The studies conducted on the sandy facies of the substratum of Banco Bay aim to characterise the sandy levels of the bay using grain-size parameters and the interpretations derived from them. The methodologies used for this characterisation consisted of determining grain-size parameters, namely quantiles, quartiles, mean, mode, standard deviation, skewness, and kurtosis. The parameters were calculated using the classical method of moments. The main grain-size analyses made it possible to identify quasi-coarse sands throughout all the wells studied, indicating a moderate to turbulent palaeocurrent in the environment. Poorly sorted sands are more abundant than moderately sorted sands in all the boreholes studied. This sorting of the sands may be attributed to the currents that transported them. The currents were somewhat more regular for the moderately sorted sands, whereas the poorly sorted sands were transported by irregular currents. The curves are almost unimodal in all the wells. The results of these curves indicate one main sediment source supplying the entire bay. Skewness is generally positive, indicating that there are more grains with sizes greater than the mean. The different kurtosis values show a slight overall predominance of leptokurtic distributions across the tabulated samples. The grain-size parameters determined made it possible to characterise the sandy levels identified in the substratum of Banco Bay. These findings contribute to a better understanding of the coastal sedimentary basin, particularly the sands deposited on the bottom that form the substratum of the bay.

Integrated Hydrological and Hydraulic Approach for the Design of the Sorey Bridge under a Context of Climate Variability (Niamey Region, Niger)

Harouna Souley — 2026-09-18

The increasing hydroclimatic variability observed in the Sahel poses a major challenge to the design and safety of road infrastructure exposed to flooding. This study applies an integrated hydrological and hydraulic approach to the design of the Sorey Bridge in the Niamey Region of Niger. The methodology combines precipitation-frequency analysis, GIS-based morphometric characterisation of the watershed, estimation of the 10-year flood using the ORSTOM and CIEH methods, extrapolation of the 100-year flood using the GRADEX method, and hydraulic analysis based on the Manning–Strickler relationship. The watershed covers 1,359.75 km², with a perimeter of 285.32 km and a main channel length of 50.39 km. Rainfall analysis for 1991–2000 shows marked interannual variability, with mean annual precipitation ranging from 410.7 to 816.3 mm and a maximum daily rainfall of 129 mm. The 10-year discharges estimated by ORSTOM and CIEH are 196.22 and 225.86 m³/s, respectively, giving an adopted mean design discharge of 211.04 m³/s. The GRADEX method gives a 100-year discharge of 896.78 m³/s. Hydraulic analysis yields a flow depth of 3.40 m, a mean velocity of 2.90 m/s, and a backwater rise of 0.208 m. Total pier scour is 3.86 m. The proposed protection comprises 0.74-m-diameter riprap, with a 3.00-m width and 2.22-m layer thickness, together with a 2.00-m freeboard. These parameters support the hydraulic design of the Sorey Bridge under extreme flood conditions.

Moss-dwelling Testate Amoebae in Patratu Valley, Jharkhand, India: A Pilot Study

V. M. Sathish Kumar — 2026-09-23

Testate amoebae are shell-bearing protists that occur in a wide range of terrestrial and aquatic habitats and can provide useful information on microbial diversity and environmental conditions. This pilot study documents moss-dwelling testate amoebae from Patratu Valley, Jharkhand, India, where information on these organisms has been limited. Moss samples were collected from soil- and wall-associated microhabitats on 22 February 2026 and processed using the non-flooded Petri dish method. Permanent slide preparations were examined microscopically for species-level identification, and registered slides were deposited in the National Zoological Collections of the Gangetic Plains Regional Centre, Zoological Survey of India, Patna. The survey recorded 12 species belonging to five genera and five families. The recorded taxa included species of Cyclopyxis, Difflugia, Centropyxis, Euglypha, and Trinema. These observations provide a preliminary inventory of testate amoebae associated with moss microhabitats in the study area and extend baseline information on their regional occurrence. Because the investigation was based on a single pilot survey and did not quantify abundance or environmental variables, the recorded species richness should not be interpreted as a complete assessment of the local assemblage or as evidence of ecosystem condition. Broader spatial and seasonal sampling, together with standardised measurements of environmental variables, will be required to evaluate patterns of assemblage composition and their potential value in environmental monitoring.

Integrated Physicochemical, Hydrochemical, Trace-element and Microbiological Assessment of Groundwater across Contrasting Geological Settings

Madu Onyeka Emmanuel — 2026-10-01

Groundwater is an important source of domestic water supply, but its quality may vary according to geological setting, mineral–water interactions and microbiological contamination. This study evaluated the physicochemical, hydrochemical, trace-element and microbiological characteristics of groundwater across Basement Complex, Younger Granite, shale/sedimentary and weathered-regolith geological settings. Groundwater samples were analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, total hardness, alkalinity, major ions, selected trace and potentially toxic elements, heterotrophic bacteria, total coliforms, faecal coliforms, Escherichia coli and enterococci. Hydrochemical facies were determined from the major-ion composition, while differences among geological settings were evaluated using one-way analysis of variance, and relationships between chemical and microbiological variables were assessed using Pearson's correlation analysis. The groundwater was slightly acidic to near neutral, with pH values ranging from 6.21 ± 0.14 to 6.78 ± 0.16. Basement Complex groundwater exhibited the highest EC (486 ± 42 µS/cm), TDS (312 ± 28 mg/L), total hardness (146 ± 12 mg/L), calcium (48.6 ± 4.2 mg/L), magnesium (18.4 ± 2.1 mg/L) and bicarbonate (118 ± 10 mg/L). The shale/sedimentary setting recorded the highest concentrations of several trace elements, including Pb (0.014 ± 0.003 mg/L), Cd (0.0026 ± 0.0005 mg/L), Cr (0.018 ± 0.004 mg/L) and Ni (0.021 ± 0.004 mg/L). Ca–Mg–HCO₃ was the predominant hydrochemical facies. Microbiological contamination varied spatially, with weathered-regolith groundwater recording the highest total coliforms (31 ± 7 CFU/100 mL), faecal coliforms (15 ± 4 CFU/100 mL), E. coli (11 ± 3 CFU/100 mL) and enterococci (9 ± 3 CFU/100 mL). Significant differences occurred among geological settings for the assessed physicochemical, chemical and microbiological parameters (p < 0.05). Turbidity and nitrate showed positive associations with the principal microbiological indicators. The findings demonstrate that geological setting influences groundwater mineralisation and trace-element distribution, while microbiological quality may respond to additional factors associated with groundwater vulnerability and contamination pathways. Integrated chemical and microbiological monitoring is therefore important for evaluating groundwater quality and its suitability for domestic use.

Assessment of Drinking-water Quality Intended for Poultry Production: A Baseline Study from Salem District, Tamil Nadu, India

R. Sivachandiran — 2026-10-05

Water quality is an important component of poultry production and may influence bird health, performance, farm infrastructure and biosecurity. The present study was conducted to assess the physicochemical and microbiological quality of water sources intended for poultry-farm use in Salem district. A total of 30 water samples were collected by convenience sampling from accessible sites associated with poultry farms before the commencement of poultry production. Physicochemical parameters, including pH, electrical conductivity (EC), total dissolved solids (TDS), salinity and total hardness were measured using an LMMP30 Water Quality Multiparameter. Coliforms were estimated by the five-tube most probable number (MPN) method using MacConkey lactose broth. The pH ranged from 6.90 – 8.80, with a mean of 7.85 ± 0.45. EC ranged from 592 – 46,800 µS/cm, while TDS ranged from 297 – 2,530 mg/L. Salinity ranged from 0.23 – 2.70 ppt and total hardness ranged from 240 – 1,692 mg/L. Coliform counts ranged from 0 – 170 MPN/100 mL, with detectable coliforms present in 24 (80.0%) samples. The findings demonstrated considerable variation in the physicochemical and microbiological quality of water sources intended for poultry production. The presence of coliforms and elevated mineralisation in several sources highlight the importance of baseline water-quality assessment before farm establishment. Regular monitoring, appropriate water sanitation and further seasonal and pathogen-specific investigations are recommended.

From Marshlands to Livelihood Shifts: A 30-Year Socio-Ecological Analysis of Coastal Adaptation in Côte d'Ivoire

Oulai Jean-Gautier Kpan — 2026-10-10

This study assessed the socio-economic effects of climate variability and community-led adaptation along the southeastern coastal zone of Côte d’Ivoire, from Abidjan to Aboisso. It combined a household survey of 280 participants with a diachronic land-use and land-cover analysis based on Landsat imagery from 1986, 2000, and 2016. Climate-change awareness was reported by 99.6% of respondents, while 81.4% associated climate variability with declining crop yields, product quality, and household income. The survey identified multiple responses to climatic and livelihood pressures, including soil fertilisation, introduction of new crops, improved crop varieties, staggered sowing, localised reforestation, and livelihood diversification. Some households moved partly or completely away from primary crop production towards poultry farming, commerce, transport, and migration. Remote-sensing analysis showed marked landscape restructuring over the 30-year period. Built-up areas increased by 7.71%, dense forest declined by 9.38%, and marshlands decreased from 2.69% of the study area in 1986 to 0.00% by 2000. Former marshland areas were subsequently used for rice cultivation, indicating a shift towards lowland farming under changing environmental and livelihood conditions. The findings show that local adaptation is expressed through interconnected agricultural, socio-economic, and land-use adjustments. However, these responses should be interpreted in relation to both climatic variability and concurrent anthropogenic pressures.

Spatiotemporal Monitoring of Heavy Metal Attenuation and Ecological Risk Dynamics in Oil-degraded Soils of Eleme, Niger Delta, Nigeria

Nurudeen Ahmed Onomhoale — 2026-10-13

This study aims to address this gap by using spatiotemporal mapping and monitoring of heavy-metal concentrations and assessing their corresponding pollution levels and ecological risks to evaluate the environmental quality of oil-degraded sites. This study investigates the presence of metals, their pollution levels, and the associated ecological risks at an oil-spill site in Eleme, Nigeria. Twenty-six soil samples were analysed, comprising twenty-two from the spill site and four from reference sites. The concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) were determined during two sampling phases at a six-month interval. The geoaccumulation index (Igeo) showed values < 2 after the first sampling phase, indicating moderate contamination, and values < 1 after the second phase, signifying uncontaminated levels. The metal pollution index (MPI) decreased from 1.01 to 0.59, indicating a significant reduction in pollution associated with post-remediation activities such as metal immobilisation and leaching, as well as environmental processes such as rainfall, weathering, and groundwater movement. The contamination factor (CF) primarily indicated low contamination for most heavy metals across the samples, except Cd, which remained persistent, while the potential ecological risk index (PERI) revealed a shift from moderate to low ecological risk. The findings showed progressive contaminant reduction and improved environmental quality, with heavy-metal concentrations spatially concentrated in the southern parts of the site and significant second-phase reductions, particularly for Cr and Pb, which fell within permissible limits of the U.S. Environmental Protection Agency (USEPA). However, Cd, Zn, and Fe remained persistent in certain areas, reflecting ongoing attenuation dynamics that may affect heavy-metal behaviour and mobility and highlighting the need for targeted remedial efforts and public health protection.

GIS-based Morphotectonic and Morphometric Analysis of Tamsa River Watershed in Eastern Uttar Pradesh

Ankit — 2026-10-14

The present study focuses on the morphometric characterisation of the Tamsa River basin in eastern Uttar Pradesh using a Geographic Information System (GIS), a Digital Elevation Model (DEM), and Survey of India (SOI) topographical data. Morphometric analysis provides an effective approach for understanding drainage-network characteristics, basin geometry, geomorphic development, hydrological behaviour, and the influence of geological and topographical conditions. The drainage network comprises 217 stream segments and is classified as a fourth-order basin according to Strahler's stream-ordering system. The drainage pattern is predominantly dendritic, indicating relatively homogeneous lithological conditions. The mean bifurcation ratio of 1.76 and weighted bifurcation ratio of 1.82 suggest comparatively limited structural and tectonic control over drainage development. The areal morphometric parameters indicate a low drainage density (0.194 km/km²), low stream frequency (0.027 streams/km²), low drainage intensity (0.16), and a high constant of channel maintenance (5.26 km²/km), suggesting relatively high infiltration and limited surface runoff. The elongation ratio (0.47), circularity ratio (0.08), and form factor (0.17) indicate an elongated basin configuration with a comparatively delayed concentration of runoff. The morphotectonic parameters, including the sinuosity index (1.0), hypsometric integral (0.50), and asymmetry factor (50), indicate a relatively stable and mature geomorphic setting. Overall, the morphometric characteristics provide important insights into the hydrological response, geomorphic evolution, and watershed-management requirements of the Tamsa River basin.

Bioremediation Potential of Spent Mushroom Substrate and Costus afer Bagasse for the Removal of Petroleum Hydrocarbon Xenobiotics (TPH, TPAH, and TMAH) from Contaminated Soil

Emuka, Ugochukwu Darlington — 2026-10-14

Spent mushroom substrate (SMS) and Costus afer bagasse (CAB) are abundantly available agro-wastes in the Niger Delta region of Nigeria and may serve as cost-effective amendments for the remediation of petroleum hydrocarbon-contaminated soils. This study evaluated the bioremediation potential of SMS and CAB applied at three amendment rates (0.5, 1.0, and 1.5 kg) to sandy-loam soil contaminated with Bonny Light crude oil at low, medium, and high contamination levels (250 g, 500 g, and 750 g per 10 kg soil, respectively) over a 120-day period. Treatment performance was assessed using total petroleum hydrocarbon (TPH), total polycyclic aromatic hydrocarbon (TPAH), and total monocyclic aromatic hydrocarbon (TMAH) concentrations. Statistical analyses, including analysis of variance (ANOVA) and multiple linear regression, were conducted using Minitab® v19 at a 95% confidence level. Results indicated significant reductions (p < 0.05) in hydrocarbon concentrations across all amended treatments relative to the control. The highest remediation efficiency was achieved with 1.5 kg SMS (T4), recording TPH reductions of 93.20%, 89.80%, and 87.16% under low, medium, and high contamination levels, respectively. Although treated soils met Nigerian regulatory intervention limits, residual concentrations remained above target values. Overall, SMS demonstrated greater remediation efficiency than Costus afer bagasse. These findings suggest that locally available agro-wastes, particularly SMS, can significantly reduce the cost and duration of bioremediation of crude oil-contaminated soils in the Niger Delta.