Trace Metals in Water Intended for Human Consumption from Urban and Rural Areas of Satu Mare County, Romania: Spatial–Temporal Patterns and Health Risk

This study evaluated the occurrence, spatial distribution, and associated human health risks of trace metals in water intended for human consumption from urban and rural areas of Satu Mare County (northwestern Romania) based on monitoring data collected between 2022 and 2024. A total of 271 samples from 122 localities were analyzed for As, Cd, Cr, Mn, Ni, Pb, and Se using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS). Spatial analysis, non-parametric statistics, Spearman correlation, and principal component analysis (PCA) were applied to identify distribution patterns and differences between supply systems. Arsenic was identified as the main contaminant of concern, with concentrations reaching 320.5 µg/L, primarily in rural groundwater sources. Most other metals remained below regulatory limits, and elevated concentrations were spatially localized rather than widespread. Non-carcinogenic risk (HRI > 1) was observed in 5.74% of samples, while arsenic-related carcinogenic risk (ILCR > 10−6) occurred in a limited number of locations in 2024, with no values exceeding 10−4. Risk estimates were based on total arsenic concentrations and should be interpreted conservatively due to the lack of speciation. No statistically significant differences between urban and rural areas were observed for most metals, except for manganese. Multivariate analysis revealed distinct geochemical behaviors, with a Pb–Ni–Se–Cd cluster in rural samples, while arsenic and manganese showed more independent patterns consistent with redox-controlled processes. Urban samples showed more coherent patterns and higher variance explained by PCA (78.9%) compared to rural datasets (60.1%). Risk estimates were based on total arsenic concentrations and should be interpreted conservatively. The findings highlight the vulnerability of decentralized groundwater systems and support targeted monitoring strategies in line with Directive (EU) 2020/2184.