Arsenic Pollution in Shour River and Groundwater at Rafsanjan Plain.

Shour River and large alluvial fans at Rafsanjan plain in Kerman Province of Iran have groundwater that are exploited for drinking and also irrigation of about 300 ha of pistachio growing lands. This paper presents an overview of groundwater arsenic pollution in this area: arsenic concentrations ranged from 4-278 μg/L there (average 59.25 μg/L) which is much higher than acceptable level, 10 μg/L. About 85.3% of water samples have arsenic concentrations above 10 μg/1, the World Health Organization, WHO, guideline value, and 43.9% of samples have arsenic above 50 μg/1, the Indian standards for arsenic in drinking water. The groundwater arsenic pollution in this area seems to be caused by reductive dissolution of arsenic present in adjacent mountainous volcanic rocks. The pollution problems of Shour River which originates from central Iranian volcanic belt where Sarcheshmeh copper mine, the second largest copper deposit in the world, located there, also are affected from acid mine drainage originating from waste dumps in this mine. Unlike groundwaters in deltaic environments of Bangladeshtype, here the increase in pH which is mainly as a result of increase in Na concentration, leads to enhancement of arsenic solubility and its release from the surfaces of Iron oxides or sulfides without helping Fe-oxide solution in these oxidizing environments. Although few cases of arsenic-related health problems are reported in this area, as it takes more than 10 years for symptoms of chronic arsenic poisoning to be detected, the population at risk of chronic arsenic poisoning is this area might be noticeable. [ABSTRACT FROM AUTHOR]