This study addresses the comparative influence of physicochemical parameters on the dissolution of Pb and its levels in the groundwater of former Pb mining areas in Kabwe and non-mining areas in Lusaka, Zambia. This cross-sectional study analyzed 61 groundwater samples from hand pump boreholes using atomic absorption spectrometry. Physicochemical parameters were measured, including electrical conductivity (EC), temperature, total dissolved solids (TDS), and pH. Statistical analysis involved the Wilcoxon test, Spearman’s correlation, robust linear regression, Principal component analysis (PCA), and generalized additive models. Pb concentrations were particularly higher (p = 0.029; median = 0.131 mg/L) in mining areas compared to non-mining areas (median = 0.071 mg/L). The EC in the mining areas (median = 585 µS/cm) was significantly (p = 0.001) lower than those in the non-mining area (median = 1100 µS/cm). Likewise, TDS levels revealed a significant (p = 0.001) difference between the mining area (median = 303 ppm) and the non-mining area (median = 601 ppm). The median pH values for groundwater samples in the mining and non-mining areas were 6.96 and 7.27, respectively. Spearman’s rank correlation revealed a significant (rho = − 0.405; p = 0.036) inverse relationship between Pb concentrations and pH in non-mining areas. Robust linear regression and generalized additive models underscored a significant (p = 0.016) non-linear relationship between temperature and Pb across all areas, with the non-mining area demonstrating a significant (p = 0.003) non-linear relationship between temperature and pH concerning Pb. The study associates mining activities with increased Pb concentrations, underscoring it as a principal contamination source. In contrast, elemental dissolutions from the basement limestone with dolomite might increase Pb concentration in the non-mining areas. The observed positive relationship between temperature and pH in non-mining areas highlights its positive interactions with Pb mobility while temperature greatly influences Pb dissolutions in mining areas.

Groundwater contamination by lead (Pb) occurs commonly in historically mined regions and presents health risks to exposed residents. Poor documentation of elevated Pb levels in underserved regions prevents the development of environmental contamination policies and interventions. This study investigates Pb contamination and associated carcinogenic and non-carcinogenic health risks in Makululu, a large compound near the former Pb mine in Kabwe City, Zambia. We analyzed 34 drinking groundwater samples from hand pump boreholes (n = 21) and shallow wells (n = 13). Pb concentrations exceeded WHO and USEPA standards for safe drinking in 100% of boreholes (median = 0.15 mg/L) and 77% of shallow wells (median = 0.06 mg/L). Linear regression analysis identified temperature and depth as key predictors of Pb concentrations, with higher temperatures correlating with increased Pb levels (p = 0.008), and deeper boreholes (50–100 m) exhibiting significantly higher Pb concentrations (p = 0.007) than shallow wells (10 m). Health risk assessments revealed that adults consuming borehole water had an average daily dose of 0.005 mg/kg/day of Pb exceeding WHO thresholds, with hazard quotients (HQ > 1) indicating non-carcinogenic risks. The findings highlight the urgent need for policies to mitigate environmental pollution, enforce water quality standards to reduce Pb levels and protect public health in Makululu.

Exposure to potentially toxic elements (PTEs) in commonly used substances remains a serious public health concern, especially in low-regulation environments. This study assessed and compared the concentrations of five PTEs, cadmium (Cd), lead (Pb), zinc (Zn), iron (Fe), and copper (Cu), in marijuana and Aspen-brand cigarettes consumed in Bauchi, Nigeria. Using atomic absorption spectrophotometry (AAS), we analyzed PTE content in both substances after acid digestion and proper calibration. Cigarettes showed higher levels of all tested metals. Cd (3.12 μg/g) and Pb (0.88 μg/g) in cigarettes exceeded WHO limits, while marijuana contained lower levels of Cd (0.645 μg/g) and Pb (0.11 μg/g), with only Cd approaching the level that poses environmental and public health concern. Zn (71.2 μg/g), Cu (64.0 μg/g), and Fe (19.2 μg/g) were also significantly higher in cigarettes (p < 0.01). The high levels of Cd and Pb in cigarettes indicate that smokers are more exposed to harmful PTEs through inhalation than marijuana users, which points to a greater health risk from cigarette use. These findings call for stronger policies and regulations that ensure cleaner agricultural practices and industrial accountability to minimize exposure to harmful PTEs and protect community health in Bauchi.

Contaminants of emerging concern (CECs) represent a growing yet inadequately governed threat to drinking water safety in the USA. Advances in analytical technologies have detected widespread, low-level contamination from substances like per- and polyfluoroalkyl substances (PFAS), pharmaceuticals, agrochemicals, and personal care products. This raises concerns about the long-term health of humans and ecosystems. Despite growing scientific knowledge, regulatory and policy frameworks have lagged, leading to uneven protections across public water systems. Here, we assess the policy and regulatory infrastructure related to CECs nationwide across all 50 states. Only four states (8%), California, Maine, Wisconsin, and Vermont, had strong, multi-CEC policy infrastructure with enforceable standards, systematic monitoring, and investments in advanced treatment. Many states (36; 72%), distributed across regions, exhibited moderate capacity, typically focusing on PFAS rather than on comprehensive CEC management. In contrast, ten states (20%), mainly in the South and rural West, exhibited poor policy infrastructure with limited regulation, technology, and weak enforcement. These disparities reveal substantial geographic and institutional gaps in drinking water governance. By comparing US and international policies, we propose phased, practical recommendations that combine precautionary regulation, polluter accountability, innovation incentives, and transparency. These steps aim to update drinking water governance to match current chemical challenges, safeguard vulnerable communities, and prepare US water systems for an expanding list of emerging contaminants.

Parks confer well-documented benefits for human health and well-being. However, access and use remain inequitably distributed across urban populations, particularly in cities affected by environmental injustice. In Flint, Michigan, we collected survey data among 385 residents affected by the city’s 2014 water crisis to examine (i) sociodemographic disparities in objective and perceived park access, and (ii) associations between park access and use, adjusted for individual, park, and neighborhood characteristics. After full adjustment, non-Hispanic Black residents lived farther from nearby parks than non-Hispanic White residents (mean difference = −0.09 km, p = 0.024), and greater objective park distance predicted lower odds of frequent park use (OR = 0.37, 95% CI 0.19–0.72, p = 0.003). Younger age, higher income, active transportation, and more positive perceptions of neighborhood and park quality also corresponded with frequent park use. These findings suggest that park equity depends not only on spatial access but on the social and contextual conditions that make parks reachable, safe, and welcoming. This study, conducted prior to the designation of a new state park along the Flint River, also establishes a baseline for evaluating whether a major urban greening investment expands equitable park access and use in an historically disinvested community.