This study explored the land use and land cover (LULC) changes (1995–2023) in the gold mining hotspots of Mang’onyi, Sambaru, and Londoni in the Singida region of Tanzania. The study integrated remote sensing (RS) to evaluate the LULC transitions with social survey assessments (83 respondents) to determine the resident’s perceptions of the environmental, social, and economic implications of mining bridging technical data with socio-economic realities. Supervised classification of Landsat images was conducted using the random forest (RF) classifier to generate LULC maps with five classes (bareland, agricultural land, forest, built-up, and shrubs and grasses), followed by an analysis to identify LULC change trends. The results showed an overall increase in agricultural land 168.51 km² (587.55%), bareland 7.70 km² (121.45%), and built-up areas 0.55 km² (134.15%), while forest and shrubs and grasses areas declined by 97.67 km² (− 72.59%) and 79.09 km² (− 43.49%), respectively. A social survey assessment revealed residents perceived environmental (deforestation, biodiversity loss, land degradation, water, air, soil pollution), social (occupational hazards, land use conflicts, negative effects on livelihoods and culture, discrimination, child labor, community displacement), and economic (improved housing, infrastructural development, job creation, economy boost, improved access to services) impacts resulting from mining activities. Our findings underscore the importance of balancing the economic benefits of gold mining with the imperative to protect the environment and support sustainable livelihoods in the mining regions.

This study evaluated the concentrations of heavy metals in wastewater, soil, and tomatoes and Napa cabbage irrigated with effluent from the Kalobe Wastewater Stabilization Pond (KWWSP) in Mbeya, Tanzania. Human health risks were assessed using Chronic Daily Intake (CDI), Target Hazard Quotient (THQ), Hazard Index (HI), and Target Cancer Risk (TCR) indices. The results showed that cadmium (Cd) in all ponds was below the FAO/WHO permissible limits, while lead (Pb) and chromium (Cr) were below detection levels. Heavy metals in soil were found in the order of Pb (5.95 mg/kg) > Cr (0.63 mg/kg) > Cd (0.25 mg/kg), all within FAO/WHO acceptable limits, indicating suitability for agricultural use. Cd levels in Tomatoes (0.14 mg/kg) and Napa cabbage (0.40 mg/kg) exceeded permissible limits. Cr levels in the Tomato and Napa Cabbage were 1.87 and 2.10 mg/kg, respectively, and were close to the safety threshold, suggesting health concerns with long-term consumption. Cd exposure through vegetable intake was within but near acceptable limits, while Cr exposure, particularly for Napa cabbage, exceeded recommended safety thresholds. This resulted in elevated noncarcinogenic risks (THQ and HI > 1) and carcinogenic risks (TCR above the USEPA's acceptable range). These findings suggest that consuming wastewater-irrigated Tomatoes and Napa cabbage may pose human health risks. Continuous monitoring of heavy metals, safe irrigation alternatives, and cropping restrictions using inadequately treated wastewater is essential to safeguard public health and long-term environmental sustainability.

Although numerous studies have reported an increased yield upon adoption to improved agricultural practices (IAPs), yet smallholder farmers face limited access to this information. The objective of this study was to assess smallholder farmers' awareness and adoption of IAPs. A total of 206 active and registered households were surveyed by mixed sampling in the Mbeya region. The data was collected from smallholder farmers using the ODK collect tool through a well-structured questionnaire. The probit model and One-way ANOVA test were performed to identify predictor variables. Results pointed out that farming period, top dressing, flood exposure, fallowing time, soil information on IAPs, and knowledge about soil type showed a significant difference (p < 0.05) on the farmers’ adoption of IAPs. Moreover, 81% and 72% of the smallholder farmers surveyed showed a lack of awareness regarding the specific soil type and general soil information related to their farmland, respectively. Only 24% of farmers relied on agricultural experts (extension service officers) to get information on IAPs whereas 65% of the respondents were unfamiliar with neither Agricultural Extension Officers, non-governmental organizations (NGOs), Tanzania Agricultural Research Institute (TARI), nor Researchers from Higher Learning Institution (RHLI). About 59% of the female-headed households were found to have a better soil information on IAPs than men at a 5% significant level. Age and education level do not affect farmers’ adoption of IAPs with 72.5% of respondents motivated to adopt various IAPs in the surveyed area. This study highlights the need to highly consider agricultural extension officers as important agents in linking smallholder farmers with NGOs programs, agricultural research findings, and government programs to improve their livelihood. Graphical abstract

This study employed Remote Sensing and Geographical Information Systems to explore the influence of environmental factors and human-induced land use/land cover changes on the chemistry of soda-saline lakes in Northern Tanzania. Satellite-based rainfall data were sourced from the Climate Hazards Group Infrared Precipitation with Station (CHIRPS) datasets, and temperature data were obtained from MERRA-2. Monthly precipitation, temperature, and drought conditions in lake watersheds were analyzed from 1981 to 2022, while land use and land cover changes were assessed for 2000, 2014, and 2023. Soil types were acquired from the FAO Digital Soil Map of the World, while geological characteristics were sourced from the US Geological Survey database. The findings revealed that the region's climate is ideal for enhancing evapotranspiration, leading to mineral precipitation, and altering the chemistry of soda-saline lakes. The Standardized Precipitation Evapotranspiration Index revealed increased drought events in the lake basins since 1987, with prolonged drought occurrence between 2000 and 2017. The results also showed that the region is characterized by a variety of soil types, including ferric acrisols, chromic cambisols, calcic cambisols, entisols, inceptisols, eutric fluvisols, distric nitisols, humic nitisols, mollic andosols, ochric andosols, and pellic vertisols. Furthermore, the region is distinguished by diverse geological processes, from Precambrian-Cambrian to tertiary intrusive, triggered by volcanic and tectonic activity. Land use/land cover changes results indicated dynamics in the various classes with an overall decrease in areas under water bodies (−39.80 %), forests (−22.57 %) and bareland (−36.18) while agricultural land (111.01 %) built-up areas (434.72 %), shrubs and grasses (72.77 %) increased in area coverage over the 23 years study period (2000–2023). This study underscores the complex interplay between environmental variables and human activities in shaping the chemistry of soda-saline lakes.

This study investigates the metals risks in the Danube River, Hungary, and identifies the natural and anthropogenic sources using geochemical modeling. In total, 76 water samples were collected from seven sites along the river during 2018. Physicochemical and heavy metals have been analyzed. Statistical tools, including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), were applied. Water quality was assessed using the Canadian Water Quality Index (CWQI), Metal Pollution Index (MPI), Nemerow Composite Index (NCI), Hazard Quotient (HQ), Hazard Index (HI), and Carcinogenic Risk (CR). A probabilistic approach using Monte Carlo simulation was applied to evaluate uncertainty and health risks. Geochemical modeling revealed that the river is undersaturated with minerals like gypsum, anhydrite, and halite, but supersaturated with aragonite, dolomite, and calcite. The average CWQI (44.8) and Weighted Arithmetic Water Quality Index (WAWQI, 60.1) indicate that the water is unsuitable for drinking. However, Sodium Adsorption Ratio (SAR = 0.5), Sodium Percentage (Na% = 15.4), and Kelly’s Ratio (KR = 0.2), suggest favorable conditions for agricultural use. The low ecological risk index (RI = 0.5) and MPI (< 0.3) indicate minimal contamination, while the NCI (1.2) flags the right bank of Dunaföldvár as nearing a critical pollution threshold. Although non-carcinogenic health risks (HQ, HI < 1) for chromium, copper, lead, and nitrate were minimal, Monte Carlo simulation showed elevated carcinogenic risk for lead and chromium in children at the 95th percentile. These findings highlight the need for ongoing monitoring and treatment of water and offer valuable insights for sustainable water management and policy planning in Hungary.