Arsenic concentration in groundwaters in Sendai City

Abstract

Forty groundwater samples, collected in Sendai City, were analyzed for arsenic and some other chemical constituents. The average arsenic concentration is 1.1μg/l for the samples with pH 6-7, and 12 μg/l for those with pH 7-9. Thus the pH may be a major factor leaching of arsenic adsorbed on the sediments. This has been proved by leaching experiment of arsenic-containing iron (III) hydroxide with alkaline solutions. Then a prolonged contact of the groundwater with the sediments will favor the dissolution of arsenic. The groundwaters with high iron load are often rich in arsenic, suggesting that arsenic is bound to iron in the sediments.