In developing countries, poor waste management causes widespread heavy metal and toxic chemical contamination, threatening vulnerable populations. This systematic review of the health risks of waste-related heavy metals and toxic chemicals among vulnerable populations in low- and middle-income (LMICs) countries synthesizes multifaceted exposure pathways, clinical biomarker data, and localized risk thresholds. PubMed, Scopus, ScienceDirect, and ProQuest databases were searched for peer-reviewed studies published in English between 2012 and 2025. Out of the 731 records identified, two independent reviewers extracted data and appraised the quality of 21 eligible studies using Joanna Briggs Institute (JBI) Critical Appraisal Checklist, with initial variances successfully resolved via a formal consensus protocol. Primary contaminants identified were Pb, Cd, Cr, As, Hg, and Ni. Exposure pathways included soil and dust ingestion, inhalation of contaminated emissions, dermal absorption, occupational contact. Pediatric cohorts face extreme risks through ingestion and inhalation; mean blood lead reached 60.43 µg/L, breaching the World Health Organization 50 µg/L threshold, and correlated with a Full-Scale IQ decline (β= − 18.42, p < 0.05). Risk modeling showed pediatric non-carcinogenic vulnerabilities exceeded the US EPA Hazard Index baseline of 1.0 (e.g., Mn HI = 1.69), while total carcinogenic risk reached concerning level (10–5). Occupational biomarkers tracked hair mercury up to 10.8 mg/kg in miners and mean blood cyanide at 400 µg/L. Toxic waste exposures drive severe, unequal neurological, renal, hepatic, and carcinogenic burdens across LMICs. Mitigating these risks requires operationalized policies including enforcement of the Basel convention, mandatory provision of N95/P100 respirators and nitrile gloves, annual blood lead screenings, and formalizing labor contracts via Extended Producer Responsibility models.
Z. Mengesha, Kasahun Eba, Samuel Fekadu et al.· Discover Environment· 0 citations
The establishment of the invasive malaria vector Anopheles stephensi in Ethiopia threatens existing malaria control efforts. Unlike native vectors, An. stephensi thrives in both urban and rural areas, lacks clear seasonal peaks of abundance, and often breeds in artificial water containers. SumiLarv™ 2MR containing the larvicide pyriproxyfen (PPF) offers a promising method for controlling the immature stages of An. stephensi in such habitats. This habitat-randomised controlled trial evaluated the efficacy of SumiLarv™ 2MR against An. stephensi in Danan town, Somali region, Ethiopia. Entomological surveillance identified 102 large artificial containers (“birkas”) which were randomly allocated in a 1:1 ratio to receive either SumiLarv™ 2MR (treatment arm) or no treatment (control arm). SumiLarv™ 2MR was introduced into the birkas at a dose of one disc per 200 L of water. Morphological identification was performed on adult mosquitoes emerging from control containers, while molecular analysis was conducted on both morphologically identified adult mosquitoes and dead pupae collected from the control and treatment arm. The residual efficacy of PPF content of the remaining discs was also analysed. Inhibition of adult mosquito emergence was assessed every 2 weeks for 40 weeks to determine the duration of efficacy. The number of SumiLarv™ 2MR remained constant in the treatment arm throughout the study period. No significant differences were observed in water volume, pH, or temperature between the two study arms. Introduction of SumiLarv™ 2MR resulted in complete (100%) inhibition of adult emergence throughout the 40 weeks’ study period (t = 6.26, p < 0.05). Morphological identification of a sub-samples of adult mosquitoes emerging from control containers at different time points confirmed the presence of An. stephensi (99.85%) and An. gambiae s.l. (0.15%). Molecular analysis of morphologically identified adults from control containers and dead pupae from treatment containers confirmed that 98.91% were An.stephensi. Post-trial analysis showed that approximately 82.20% of the original PPF had been released from SumiLarv™ 2MR during study period. The high and sustained efficacy of SumiLarv™ 2MR demonstrated in this study suggests that it is a suitable tool for controlling An. stephensi in large artificial water storage containers.
A. Dagne, P. Doumbe-Belisse, T. Degefa et al.· Malaria Journal· 0 citations
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