Organochlorine pesticides in Ethiopian waters: Implications for environmental and human health.

Despite the global ban on organochlorine pesticides (OCPs) since the 1970s, their use continues in many developing countries, including Ethiopia, primarily due to the lack of viable alternatives and weak regulations. Nonetheless, the extent of contamination and the resulting environmental and health consequences in these countries remain inadequately understood. To address these knowledge gaps, we conducted a comprehensive analysis of reported concentrations (n=398) of OCPs (n=30) in distinct yet interconnected water matrices: water, sediment, and biota in Ethiopia. Our analysis revealed a notable geographical bias, with higher concentrations found in sediments (0.074-1161.2 µg/kg), followed by biota (0.024-1003 µg/kg) and water (0.001-1.85 µg/L). Moreover, DDTs, endosulfan, and hexachlorohexenes (HCHs) were among the most frequently detected OCPs in higher concentrations in Ethiopian waters. The DDT metabolite p,p'-DDE was commonly observed across all three matrices, with concentrations in water birds reaching levels up to 57 and 143,286 times higher than those found in sediment and water, respectively. The findings showed a substantial potential for DDTs and endosulfan to accumulate and biomagnify in Ethiopian waters. Furthermore, it was revealed that the consumption of fish contaminated with DDTs posed both non-carcinogenic and carcinogenic risks while drinking water did not pose significant risks in this regard. Importantly, the issue of OCPs in Ethiopia assumes even greater significance as their concentrations were found to be eight times higher than those of currently used pesticides (CUPs) in Ethiopian waters. Consequently, given the ongoing concerns about OCPs in Ethiopia, there is a need for ongoing monitoring, implementation of sustainable mitigation measures, and strengthening of OCP management systems in the country, as well as in other developing countries with similar settings and practices.

Heavy metals in Ethiopian drinking water and public health risks: Insights from nationwide and regional analysis.

The ambitious sustainable development goal (SDG) 6 of the United Nations, which aims to achieve universal access to safe water and sanitation by 2030, remains elusive for many developing countries like Ethiopia. This is often due to a multitude of intricate factors, including the escalating degradation of water quality. Here, we present a comprehensive nationwide and regional analysis of heavy metal pollution in drinking water sources and the associated human health risks in Ethiopia based on a dataset of 11 heavy metal concentrations (n = 975) collated from available studies. Results indicate significant variations in heavy metal pollution in drinking water sources in Ethiopia, with 44 % of the total concentration exceeding maximum permissible limits. The mean concentrations were ranked as follows: Pb (1.92 mg/L) > Zn (1.25 mg/L) > Fe (0.56 mg/L) > Mn (0.43 mg/L) > Cu (0.40 mg/L) > Co (0.30 mg/L) > As (0.12 mg/L) > Ni (0.12 mg/L) > Cr (0.10 mg/L) > Cd (0.06 mg/L) > Hg (0.04 mg/L). We found that children are more vulnerable to non-carcinogenic health risks than adults, with the highest hazard quotient (HQ) exceedances of up to a factor of 1823 and 762, respectively. Furthermore, a Monte Carlo-based probabilistic risk assessment highlighted significant concerns regarding co-exposure to multiple heavy metals. The measured concentrations, ingestion rates, and exposure frequencies were identified as sensitive parameters. Overall, a higher risk was attributed to Pb and As, with river drinking water sources and the Tigray region requiring immediate mitigation measures. In conclusion, the findings emphasize the urgent need to test and purify water before consumption and to implement effective public health interventions. Furthermore, a multifaceted approach including regular monitoring, source protection, and proper waste management is recommended to expedite the achievement of SDGs and promote water sustainability in resource-limited Ethiopia and sub-Saharan Africa.

A conceptional model integrating geographic information systems (GIS) and social media data for disease exposure assessment.

Although previous studies have acknowledged the potential of geographic information systems (GIS) and social media data (SMD) in assessment of exposure to various environmental risks, none has presented a simple, effective and user-friendly tool. This study introduces a conceptual model that integrates individual mobility patterns extracted from social media, with the geographic footprints of infectious diseases and other environmental agents utilizing GIS. The efficacy of the model was independently evaluated for selected case studies involving lead in the ground; particulate matter in the air; and an infectious, viral disease (COVID- 19). A graphical user interface (GUI) was developed as the final output of this study. Overall, the evaluation of the model demonstrated feasibility in successfully extracting individual mobility patterns, identifying potential exposure sites and quantifying the frequency and magnitude of exposure. Importantly, the novelty of the developed model lies not merely in its efficiency in integrating GIS and SMD for exposure assessment, but also in considering the practical requirements of health practitioners. Although the conceptual model, developed together with its associated GUI, presents a promising and practical approach to assessment of the exposure to environmental risks discussed here, its applicability, versatility and efficacy extends beyond the case studies presented in this study.