Arsenic determination in soils and hair from schools in past mining activity areas in Ron Phibun district,Nakhon Si Thammarat province,Thailand and relationship between soil and hair arsenic

Arsenic (As) in soils and hair collected from schools in Ron Phibun district, Nakhon Si Thammarat province, Thailand, where former tin mining operation were located, was determined by hydride generation atomic absorption spectrophotometry. The relationship between As content in soils and hair with distance from secured landfill was also investigated. Soil and hair samples were collected from 6 schools in summer (February) and rainy season (July). For soils, silt+clay (<45 µm) fraction and sand (45 µm–2 mm) fraction were analyzed. The average concentrations of arsenic in soils during summer (21.70 ± 16.79 mg/kg) and rainy season (22.45 ± 14.17 mg/kg) were at the same concentration level. The average arsenic content in hair samples was 2.24 ± 0.05 mg/kg in rainy season which was higher than 1.05 ± 0.04 mg/kg in summer. It was found that arsenic contents in hair and soils are correlated with the distance from the secured landfill. Most importantly, a positive relationship between arsenic content in hair and soil was obtained for rainy season, which indicated that arsenic in soil corresponded to arsenic in hair. The cancer risk from soils ranged from 4.48 × 10^?7 to 2.06 × 10^?6 indicating low carcinogenic risk to school children.