An Exposure Assessment of Arsenic and Other Trace Elements in Ha Nam Province, Northern Vietnam

Abstract

Concentrations of As and other trace elements were measured in groundwater, rice, hair, urine, and blood samples of people consuming As-contaminated groundwater in a village of Ha Nam province, northern Vietnam to understand the recent status of contamination and assess the possible risks of human exposure. Elevated concentrations of As in groundwater were still observed, exceeding the WHO guideline value in most of the tube wells investigated. Significant positive correlations between As concentrations in groundwater and human samples (hair and urine) were observed. Arsenic concentrations in human and hair appeared to be related to the groundwater usage habit, with higher levels found in drinking group than those in the washing group. Significant good correlations were also encountered between cumulative intakes of As, Mn, and Ba through groundwater consumption and hair concentrations. All these results indicate the chronic exposure to As and some other elements such as Mn and Ba. The total intakes of As, Mn, and Ba through rice and groundwater consumption were estimated to be ranged from 80-836, 49.3-1850, and 311-97100 µg/day, respectively. The daily intakes of As of the study area ranged from 1.6-16.7 µg/kg body wt./day, mean: 7.15 µg/kg body wt./day, in which about 85% of the subjects were above the provisional tolerable daily intake proposed by WHO.

Figure 1

Concentrations of As in urine and hair samples of two groups using groundwater for drinking (A) and washing (B). Exposure levels of group A were significantly higher than those of group B (Mann–Whitney U test, p < 0.05). (a) As concentration in urine (μg/l). (b) As concentration in hair (μg/g).

Figure 2

Relationships between the cumulative intakes of (a) As, (b) Ba, and (c) Mn through contaminated groundwater and their concentrations in human hair samples (Pearson correlation coefficients R > 0.500, p < 0.05).