Surveillance on chronic arsenic exposure in the Mekong River basin of Cambodia using different biomarkers

Thousands of Cambodia populations are currently at high risks of both toxic and carcinogenic effects through drinking arsenic-rich groundwater. In order to determine and assess the use of arsenic contents in different biological samples as biomarkers of chronic arsenic exposure from drinking arsenic-rich groundwater in Cambodia, individual scalp hair, fingernail and toenail were collected from three different provinces in the Mekong River basin of Cambodia. After washing and acid-digestion, digestate was analyzed for total arsenic by an inductively coupled plasma mass spectrometry. Chemical analysis of the acid-digested hair revealed that among 270 hair samples cut from Kandal, 78.1% had arsenic content in scalp hair (As_h) greater than the typical As_h (1.00 μg g⁻¹), indicating possible arsenic toxicity. Concurrently, 1.2% and 0.6% were found elevated in Kratie (n = 84) and Kampong Cham (n = 173), respectively. Similarly, the upper end of the ranges for arsenic contents in fingernail (As_fn) and toenail (As_tn) clipped from Kandal (fingernail n = 241; toenail n = 187) were higher than the normal arsenic content in nail (0.43–1.08 μg g⁻¹), however, none was observed elevated in both Kratie (fingernail n = 76, toenail n = 42) and Kampong Cham (fingernail n = 83; toenail n = 52). Significant positive intercorrelations between groundwater arsenic concentration (As_w), average daily dose (ADD) of arsenic, As_h, As_fn and As_tn suggest that As_h, As_fn and As_tn can be used as biomarkers of chronic arsenic exposure from drinking arsenic-rich groundwater, in which As_h is more favorable than As_fn and As_tn due to the ease of sample processing and analytical measurements, respectively.