Heavy Metal Pollution Resulting from Informal E-Waste Recycling in the Greater Accra Region of Ghana

This study investigated concentrations and spatial distributions of four heavy metals: Cadmium (Cd), Chromium (Cr), Copper (Cu), and Lead (Pb) in the soil and drainage systems resulting from informal e-waste recycling at Ashaiman, a town in the Greater Accra Region of Ghana. Twenty-four soil samples were randomly taken from two open burning sites, and three water samples from a drainage that flows through the scrapyard were digested using standard wet digestion methods. An atomic absorption spectrophotometer (AAS) was used to analyze three replicates per sampling location for the heavy metals. The results revealed that the soil and drainage samples were polluted, with the metallic levels exceeding the World Health Organization (WHO), the Food and Agricultural Organization (FAO) of the United Nations, and the Environmental Protection Agency (EPA) of Ghana limits. Geoaccumulation index (Igeo), pollution load index (PLI), and contamination factor (CF) further confirmed the contamination of the scrapyard by the heavy metals. Spatial distribution maps showed elevated levels of the heavy metals at portions designated for open burning and disposal of e-waste materials. The research corroborates studies on pollution of the environment by informal e-waste activities and underscores the urgent need for policy implementation and law enforcement to halt further pollution

Potential ecological risk assessment of heavy metals associated with abattoir liquid waste: A narrative and systematic review

The article presents a narrative and systematic review of the potential ecological risk assessment of heavy metals associated with abattoir liquid waste for knowledge advancement. The narrative review primarily focused on (i) An overview of abattoir operations; (ii) Characteristics of abattoir liquid waste; (iii) Heavy metals in the liquid waste and their health effects; (iv) Environmental impacts of abattoir liquid waste; and (v) Potential ecological risk index (RI) methodology. These provided essential literature for the systematic review. Using exclusive/inclusive criteria, 15 abattoirs that satisfied the eligibility criteria, all located in Nigeria, were used for the systematic review with meta-analysis/meta-regression. Comparative multiple linear meta-regression analyses were used to quantify the heterogeneity variances between the abattoirs based on standardized RIs (SRIs; effect sizes) using eight tau (τ) estimators in R metafor. The effects of three standardized moderators─ number of metals, metal concentrations, and relative distances between the abattoirs and a pristine environment, Gashaka-Gumti National Park (GNP), were also analyzed. The Sidik-Jonkman (SJ) estimator yielded a realistic output, and the current research findings were based on this estimator. The Cochran statistic (QE) suggested an absence of heterogeneity(p>0.99). Between-study heterogeneities, quantified by H2 (1.05), I2 (4.76%), and τ2 (0.0032 ± 0.0032 (SE)) statistics were very low, practically suggesting complete homogeneity. The moderators accounted for R*2 of 95.73% of the total explanatory capacity of the model. The beta coefficients of the moderators and intercept were significant (p-values: 0.009–0.0004). While the first two moderators showed in-phase relations with the SRIs, the third indicated an out-of-phase relation. Such links suggest the existence of abattoir-environment interactive processes. Although the abattoirs are spatially distinct and independent, their operations showed evidence-based homogeneity and posed high ecological risks. Hence, environmental legislation should be strictly enforced while ensuring human settlements are sited reasonably from abattoirs