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Fifteen organochlorine pesticides (OCPs) were determined in sediments from 14 sites in upper, middle and lower reaches of River Rwizi. Duplicate samples were collected at each site, during three sampling regimes covering the wet and dry seasons. Sediments were extracted using acetone: hexane (1:1 mixture) and clean-up was achieved using C18 cartridge. OCPs were determined using gas chromatography-mass spectrometry (GC-MS). Principal component analysis (PCA) was used to assess spatial relationships. To assess ecological health risk, the risk quotient (RQ) based on exposure and toxicity was calculated. Hazard index (HI), based on the sum of ratios of the OCP doses to permitted levels was calculated assess risk to human health. Recoveries of 54.4-93%, linearity (R²) > 0.9988, limits of detection (LoD) of 0.34-0.66 ng/kg and limits of quantification (LoQ) of 1.02-2.01 ng/kg were obtained during method validation. The total OCPs concentration was 84.34-159.5 µg/kg dry weight. Presence of OCPs in the sediment may be attributed to environmental persistence, however the presence of endosulfans implies continuing input since they have a relatively short half-life. Ecological risk quotient (RQ) values were 0.01-9780.37 while hazard index (HI) values were all less than 1. The HI for dermal exposure in children was 0.2695 and in adults it was 0.1497, exceeding the negligible risk threshold of H < 0.1. While the risk to human health was low, the high risk posed to ecology by heptachlor (RQ = 9780.37) and endosulfan II (RQ = 835.98) requires immediate mitigation.

Supplementary information: The online version contains supplementary material available at 10.1007/s44274-025-00465-7.

Toxic metal concentrations and physical chemical properties of River Rwizi surface water were determined. Aluminium, antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, potassium, lead, manganese, molybdenum, nickel, selenium, silver, thallium, thorium, uranium, vanadium, and zinc, were quantified using Inductively coupled plasma optical emission spectroscopy (ICP-OES). Physical chemical parameters were measured in-situ using a HANA meter. Heavy metal pollution index (HMPI), Contamination Degree (C_D) and Hazard index (HI) were determined by comparing measured concentrations and reference values. Efficacy of wastewater treatment was evaluated from metal concentrations at the inlet and outlet of the Wastewater Stabilization Ponds (WSP). Selenium (up to 10.35 µg/L), iron (up to 601.74 µg/L) and aluminium (up to 435.44 µg/L), were higher than the World Health Organization (WHO) recommendations of 10 µg/L, 300 µg/L and 100 µg/L respectively. The physical-chemical parameters met the drinking water standard, except for turbidity (up to 89.1 NTU) which was higher than the WHO recommendation of < 5 NTU. HMPI was 19.5-140.7 and C_D was - 12.0-18.5 showing moderate to very high pollution. The HI was 0.084-0.804 for children and 0.036-0.379 for adults. For chronic exposure, HI was 0.008-0.069 for children and 0.016-0.163 for adults. The risk to human health exceeded the negligible threshold of HI ≤ 0.1 for adults. The efficiency of removal of metals by WSPs was low (5.87-57.73%), therefore, better wastewater management methods are desirable for protection of human health.

Supplementary information: The online version contains supplementary material available at 10.1007/s44274-025-00446-w.

Climatic extremes have historically been seen as univariate; however, recent international reports have highlighted the potential for an increase in compound climate events (e.g., hot and dry events, recurrent flooding). Despite the projected increase in the frequency of compound climate events and the adoption of compound event terminology, few studies identify climate extremes as compound climate events and little evidence exists on the societal impacts of these compound climate events. This scoping review summarizes key findings and knowledge gaps in the current state of empirical studies that focus on the societal impacts of compound climate events. We identified 28 eligible studies published in four databases reporting on the societal impacts of compound climate events in four sectors: agriculture, public health, the built environment, and land use. Overall, we found the need for more research explicitly linking compound climate events to societal impacts, particularly across multiple compound climate events, rather than single case study events. We also noted several key findings, including changes in agricultural productivity, loss of habitat, increased fire risk, poor mental health outcomes, decreased health care access, and destruction of homes and infrastructure from these events. Additional research is needed both globally and locally to understand the implications of compound climate events across different geographic regions and populations to ensure responsive adaptation policies in a compound climate event framework.

Supplementary information: The online version contains supplementary material available at 10.1007/s44274-025-00185-y.

Wheat (Triticum aestivum L.) is crucial for global food security and a staple crop in Ethiopia, yet farmer yields remain low, averaging 2.7 t ha⁻¹ compared to over 5 t ha⁻¹ at research stations. This study investigates the impact of socio-economic factors, local agronomic practices, and site-specific fertilizer management on wheat production in Goba, Lemu, Siyadebr, and Basona districts of Ethiopia. A survey of 228 households analyzed the influence of these factors on wheat productivity and fertilizer use, employing descriptive statistics, t-tests, and regression models. Results indicated that crop residue retention, improved wheat varieties, and organic fertilizers significantly increased yields, while row fertilizer application at planting had a negative effect. Fertilizer application rates varied significantly among farmers and were influenced by practices like top-dressing, monocropping, and participation in agricultural training. District-level differences in yield and fertilizer response highlighted the need for site-specific management. Multiple regression analysis revealed that key predictors of fertilizer use included cultivated land area, household income, education, small ruminant ownership, and extension contact, with larger land ownership, higher income, organic fertilizer use, and extension access being the most significant. Average yield increases due to site-specific fertilizer applications varied across districts. Overall, significant yield gains were achieved through site-specific fertilizer application across the four districts, with an average yield of 5.3 Mg ha⁻¹, compared to approximately 4 Mg ha⁻¹ using the local farmers' fertilizer application rates. This study underscores the importance of considering local agroecological conditions in fertilizer management to boost wheat productivity and support food security and economic development in Ethiopia.