Abstract
Arsenic and other trace elements were analysed in natural waters and human biological samples (scalp hair, nails and blood serum) from the high-arsenic provinces of Santa Fe and San Juan in Argentina by inductively coupled plasma mass spectrometry (ICP-MS). Arsenic species were also analysed in waters from Santa Fe and Rio Negro (low-arsenic province) using a solid phase extraction (SPE) technique and evaluated in relation to pH and redox potential (Eh). In Santa Fe and San Juan the water arsenic levels typically exceeded the World Health Organisation (WHO) and Argentine standard for drinking water of 10 μg/1 As, ranging 11.1 - 1050 and 1.49 - 14900 μg/l As, respectively. The impact of this arsenic exposure was reflected in the hair (0.03 - 7.85 mg/kg As), fingernail (0.08 - 16.7 mg/kg As) and toenail (0.07 - 21.1 mg/kg As) washed samples from Santa Fe, with statistically significant correlations (Spearman, P < 0.01) observed against the well water across the whole population. In contrast, no statistically significant correlations (at P < 0.05) were found between the samples from San Juan: hair, 0.01 - 241.7 mg/kg As; toenails: 0.04 - 0.55 mg/kg As, and; blood serum 0.26 -721 μg/l As. The relationship between arsenic exposure and the presence of a chronic health disorder, specifically type 2 diabetes mellitus (T2DM), was evaluated in both populations. The toenail arsenic levels in the healthy/control participants were significantly higher (Mann-Whitney U-test, P < 0.01), compared to those with a chronic health disorder, including T2DM. These differences were thought to be due to an improved arsenic metabolism in individuals with a high body mass index (BMI). Further differences were found for hair and blood serum, with significantly (P < 0.01) higher levels of arsenic observed in the samples from the T2DM population, suggesting a relationship between arsenic and T2DM. A number of statistically significant correlations were found between arsenic, selenium and vanadium in the biological samples from the control and T2DM groups. However, due to the complexity of T2DM, no conclusive relationships could be found between this disorder and arsenic. A further study was conducted on the geothermal waters from Copahue-Caviahue in Argentina and the Taupo Volcanic Zone (TVZ) in New Zealand. Analysis of the Upper Rio Agrio waters on Copahue volcano (466 - 614 μg/l As) indicated that the volcano could be a source of the arsenic contamination across Argentina. In addition, the geothermal waters in New Zealand highlighted a potential minor exposure route of dermal absorption which may affect bathers in these waters or individuals using high-arsenic ground or surface waters for self-washing in Argentina.