Arsenic levels in the groundwater of Korea and the urinary excretion among contaminated area

Drinking water is a main source of human exposure to arsenic. Hence, the determination of arsenic in groundwater is essential to assess its impact on public health. Here, we report arsenic levels in the groundwater of 722 sites covering all six major provinces of Korea. Water was sampled in two occasions (summer, 722 sites and winter, 636 sites) and the arsenic levels were measured with highly sensitive inductively coupled plasma-mass spectrometry method (limit of detection, 0.1 mu g/l) to encompass the current drinking water standard (< 10 mu g/l). Seasonal variation was negligible, but the geographical difference was prominent. Total arsenic in groundwater ranged from 0.1 to 48.4 mu g/l. A 88.0-89.0% of sites were < 2.0 mu g/l and the remaining ones generally did not exceed 10 mu g/l (6.4-7.0%, 2.0-4.9 mu g/l; 2.4-3.0%, 5.0-9.9 mu g/l). However, some areas (1.0-9.2%) exhibited >10 mu g/l. Notably, urinary arsenic excretion of people around these regions was markedly higher compared with non-contaminated areas (< 5 mu g/l) (79.7 +/- 5.2 mu g/g (N = 122) vs 68.4 +/- 5.4 mu g/g (N=65) creatinine, P = 0.052). All stratified analysis also revealed higher urinary excretion, where a statistically significant difference was noted for non-smokers (85.9 +/- 12.7 vs 54.0 +/- 6.3, P=0.030), suggesting that arsenic contaminated groundwater may contribute to its systemic exposure.