Potential risk and source distribution of groundwater contamination by mercury in district Swabi, Pakistan: Application of multivariate study

This study identified mercury (Hg) concentration in groundwater of District Swabi, Pakistan. The objective of the study was to find geochemistry, health risk and source distribution pattern. Therefore, groundwater ( n = 38) were collected from three hydrological environments, viz. shallower (10–20) m, middle depth (25–45) m and deeper depth (50–90) m aquifers. The water samples were tested for Hg, and results showed in the form of lowest concentration (0.16 µg/L) and highest concentration (2.0 µg/L) were recorded in deeper and shallower aquifers. Thus, shallower aquifer has been more contaminated than deeper aquifer. Most groundwater samples (68.4%) exceeded the guidelines of Hg (1.0 µg/L) recommended by WHO. The results of Hg exceeded WHO recommended level of 1.0 µg/L. Similarly, the PLI and GRQ also showed moderate pollution of Hg in the groundwater samples. The study showed that the inhabitants of the area may be exposed to several health problems. The GRQ technique revealed that the drinking groundwater sources with relatively high concentration of Hg are extremely unfit for drinking purposes.