Hair and toenail arsenic concentrations of residents living in areas with high environmental arsenic concentrations.

Abstract

Surface soil and groundwater in Australia have been found to contain high concentrations of arsenic. The relative importance of long-term human exposure to these sources has not been established. Several studies have investigated long-term exposure to environmental arsenic concentrations using hair and toenails as the measure of exposure. Few have compared the difference in these measures of environmental sources of exposure. In this study we aimed to investigate risk factors for elevated hair and toenail arsenic concentrations in populations exposed to a range of environmental arsenic concentrations in both drinking water and soil as well as in a control population with low arsenic concentrations in both drinking water and soil. In this study, we recruited 153 participants from areas with elevated arsenic concentrations in drinking water and residential soil, as well as a control population with no anticipated arsenic exposures. The median drinking water arsenic concentrations in the exposed population were 43.8 micro g/L (range, 16.0-73 micro g/L) and median soil arsenic concentrations were 92.0 mg/kg (range, 9.1-9,900 mg/kg). In the control group, the median drinking water arsenic concentration was below the limit of detection, and the median soil arsenic concentration was 3.3 mg/kg. Participants were categorized based on household drinking water and residential soil arsenic concentrations. The geometric mean hair arsenic concentrations were 5.52 mg/kg for the drinking water exposure group and 3.31 mg/kg for the soil exposure group. The geometric mean toenail arsenic concentrations were 21.7 mg/kg for the drinking water exposure group and 32.1 mg/kg for the high-soil exposure group. Toenail arsenic concentrations were more strongly correlated with both drinking water and soil arsenic concentrations; however, there is a strong likelihood of significant external contamination. Measures of residential exposure were better predictors of hair and toenail arsenic concentrations than were local environmental concentrations.

Comparison of arsenic levels in fingernails with urinary As species as biomarkers of arsenic exposure in residents living close to a coal-burning power plant in Prievidza District, Slovakia

“…Nails are more resistant to extensive washing procedures, thus the problem of external contamination may be overcome. This assumption is supported by the recent findings of Hinwood et al (2003). Interindividual variability was lower in toenail As and correlations with environmental concentrations were improved when compared with hair As.…”

“…The geometric mean of fingernail As among 36 employees exposed to As from soil at a Superfund site was 0.27 mg/g (Hewitt et al, 1995). Hinwood et al (2003) reported high geometric mean toenail As levels of 21.7 mg/g (n ¼ 21) in a group (n ¼ 21) exposed to As via drinking water, of 32.1 mg/g in a group (n ¼ 22) exposed to As via soil, and also one rather high value of 3.35 mg/g in the control group (n ¼ 8). The toenail As concentrations reported by Karagas et al (2001) ranged from 0.01 to 0.81 mg/g (geometric mean: 0.094 mg/g) among controls (n ¼ 524), from 0.01 to 2.03 mg/g (geometric mean: 0.098 mg/g) among a basal cell carcinoma group (n ¼ 284) and from 0.01 to 2.57 mg/g (geometric mean 0.090 mg/g) among a squamous cell carcinoma group (n ¼ 587).…”

“…No clear conclusions can be drawn from these data due to the very different aims and years of performance of the 11 studies summarized. More recent investigations show that As concentrations in nail tissue (fingernails or toenails) reflect environmental As exposure mainly from drinking water (Karagas et al, 1996;Lin et al, 1998;Hinwood et al, 2003;Mandal et al, 2003) and also from soil (Hinwood et al, 2003) as well as occupational As exposure (Agahian et al, 1990).…”

“…Lin et al (1998) found that hair, fingernails or urine samples served as equally effective biomarkers of exposure in patients with blackfoot disease from Taiwan, while Karagas et al (2001Karagas et al ( , 2002 reported that toenails reflect the As intake from drinking water better than urinary As species. Toenail and hair samples were assumed to be useful biomarkers for As Arsenic levels in fingernailsexposure to both contaminated water and soil (Hinwood et al, 2003).…”

“…The problem of external contamination is thought to be lower in nails (Mandal et al, 2003). Hinwood et al (2003) found a strong correlation between toenail As concentrations with both As levels in drinking water and soil, while this association was less pronounced when using hair. Karagas et al (2001Karagas et al ( , 2002 reported that As levels in toenails are a reliable long-term biomarker of total As exposure and reflect the intake of As from drinking water at low levels better than the concentrations of total As and As species in urine.…”