A systematic review and meta-analysis of radon risk exposure from drinking water resources in Nigeria.

Elevated radon concentrations in drinking water pose an increased risk of cancer among nonsmokers. A Monte-Carlo Simulation was employed to assess the effective dose and cancer risk associated with radon exposure in humans, utilizing a systematic review and meta-analysis of related studies. These studies were sourced from databases including PubMed, Web of Science, Scopus, Science Direct, and Google Scholar, focusing on drinking water from Nigeria's six geopolitical zones. The random effects models revealed a 222Rn concentration in drinking water of Nigeria at 25.01, with 95% confidence intervals (CI) of 7.62 and 82.09, indicating significant heterogeneity of (I2 = 100%; p < 0.001). The probabilistic risk of effective dose revealed a best-scenario (P 5%) at Kundiga and Magiro that exceeded the World Health Organization's (WHO) recommended effective dose limit of 200 µSv/y. Conversely, the worst-case scenario (P 95%) indicated concentrations surpassing the recommended limit at Kundiga, Edbe, Magiro, Ekiti, and Abeokuta. Excess Life Cancer Risk for infants, children, and adults attributed to the ingestion and inhalation of radon from various drinking water sources exceeded the recommended values of 0.2 x 10-3 established by the International Commission on Radiological Protection (ICRP) and the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). It underscores the necessity for treating radon-polluted water, employing methos such as aeration and granular activated carbon (GAC) processes.

Potentially toxic metals in irrigation water, soil, and vegetables and their health risks using Monte Carlo models.

Food safety has become a serious global concern because of the accumulation of potentially toxic metals (PTMs) in crops cultivated on contaminated agricultural soils. Amongst these toxic elements, arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) receive worldwide attention because of their ability to cause deleterious health effects. Thus, an assessment of these toxic metals in the soils, irrigation waters, and the most widely consumed vegetables in Nigeria; Spinach (Amaranthushybridus), and Cabbage (Brassica oleracea) was evaluated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentration (measured in mg kg-1) of the PTMs in the soils was in the sequence Cr (81.77) > Pb(19.91) > As(13.23) > Cd(3.25), exceeding the WHO recommended values in all cases. This contamination was corroborated by the pollution evaluation indices. The concentrations (measured in mg l-1) of the PTMs in the irrigation water followed a similar pattern i.e. Cr(1.87) > Pb(1.65) > As(0.85) > Cd(0.20). All the PTMs being studied, were found in the vegetables with Cr (5.37 and 5.88) having the highest concentration, followed by Pb (3.57 and 4.33), and As (1.09 and 1.67), while Cd (0.48 and 1.04) had the lowest concentration (all measured in mg kg-1) for cabbage and spinach, respectively. The concentration of the toxic metals was higher in spinach than in cabbage, which may be due to the redistribution of the greater proportion of the metals above the ground tissue, caused by the bioavailability of metals in the aqueous phase. Expectedly, the hazard index (HI),and carcinogenic risk values of spinach were higher than that of cabbage. This implies that spinach poses potentially higher health risks. Similarly, the Monte Carlo simulation results reveal that the 5th percentile, 95th percentile, and 50th percentile of the cumulative probability of cancer risks due to the consumption of these vegetables exceeds the acceptable range of 1.00E-6 and 1.00E-4. Thus, the probable risk of a cancerous effect is high, and necessary remedial actions are recommended.

Groundwater pollutants characterization by geochemometric technique and geochemical modeling in tropical savanna watershed.

Multiple interactions of geogenic and anthropogenic activities can trigger groundwater pollution in the tropical savanna watershed. These interactions and resultant contamination have been studied using applied geochemical modeling, conventional hydrochemical plots, and multivariate geochemometric methods, and the results are presented in this paper. The high alkalinity values recorded for the studied groundwater samples might emanate from the leaching of carbonate soil derived from limestone coupled with low rainfall and high temperature in the area. The principal component analysis (PCA) unveils three components with an eigenvalue > 1 and a total dataset variance of 67.37%; this implies that the temporary hardness of the groundwater and water-rock interaction with evaporite minerals (gypsum, halite, calcite, and trona) is the dominant factor affecting groundwater geochemistry. Likewise, the PCA revealed anthropogenic contamination by discharging [Formula: see text] [Formula: see text][Formula: see text] and [Formula: see text] from agricultural activities and probable sewage leakages. Hierarchical cluster analysis (HCA) also revealed three clusters; cluster I reflects the dissolution of gypsum and halite with a high elevated load of [Formula: see text] released by anthropogenic activities. However, cluster II exhibited high [Formula: see text] and [Formula: see text] loading in the groundwater from weathering of bicarbonate and sylvite minerals. Sulfate ([Formula: see text]) dominated cluster III mineralogy resulting from weathering of anhydrite. The three clusters in the Maiganga watershed indicated anhydrite, gypsum, and halite undersaturation. These results suggest that combined anthropogenic and natural processes in the study area are linked with saturation indexes that regulate the modification of groundwater quality.