Investigation of metal(loid) concentrations in drinking water and urine: A biomonitoring study in Qom, central Iran

<h2>Abstract</h2> The main purpose of this study was to assess metal(loid) concentrations in drinking water and urine samples from adults in Qom, Iran. Additionally, the study aimed to analyze these concentrations based on age, sex, and season, and to investigate the relationship between each metal(loid) level across two different matrices (drinking water and urine). A total of 180 samples, comprising 90 drinking water and 90 morning urine, were collected from 45 participants during both summer and winter. After preparation and digestion, the samples were injected into an ICP-OES device and the concentrations of 19 metal(loid)s (Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Tl, V, Zn) were measured. Demographic information about the participants was also collected. The highest metal(loid) concentrations (mean[range]) were for B (39.60[1.37–345.18]), Al (33.77[0.04–818.74]), and Li (26.31[0.48–88.59]) as μg/L in drinking water, and for B (1722.17[367.32–13397.82]), Zn (373.48[70.52–1861.95]), and Al (121.04[17.75–510.65]) as μg/g creatinine in urine samples. Except for Al in 6.67 % of drinking water samples, the median concentrations of all metal(loid)s were below the Iranian standards. However, Hg, Tl, and Li exceeded USEPA standards in 100 %, 83.3 %, and 77.8 % of the samples, respectively. Urinary Mo decreased with increasing age. Fe, Li, and Tl in drinking water, and Ba, Fe, and Cr in urine, showed statistically significant seasonal differences. Between each metal(loid) level across drinking water and urine, a weak positive correlation was observed for Hg and Li in winter, and for Ba in summer, but no correlation was found for the others. This study highlights the importance of monitoring of metal(loid)s in drinking water, as high levels of certain metal(loid)s (such as Hg, Tl, and Al) can have adverse health effects. Totally, the study provides valuable insights into the seasonal variations and potential health impacts associated with metal(loid)s exposure in Qom, emphasizing the need for continued monitoring and further researches to ensure the safety of drinking water and public health.