Occurrence,distribution and source of arsenic in deep groundwater wells in Maydavood area,southwestern Iran |
| |
Authors: | M Chitsazan M S Dorraninejad A Zarasvandi S Y Mirzaii |
| |
Institution: | (1) Department of Geology, School of Science, Shahid Chamran University, P. O. Box 65355-141, Ahvaz, Iran |
| |
Abstract: | Groundwater in some deep wells of Maydavood aquifer, southwestern Iran, contains relatively high concentrations of arsenic.
Detailed hydrochemical analysis of these groundwaters (with ICP-OES instrument) showed that concentrations of iron, manganese,
nickel, and vanadium are also high in them and concentrations of total arsenic in 81% of deep wells are greater than World
Health Organization’s permissible value (10 ppb). XRF analysis of surrounding geological formations and aquifer sediments
proposed that original source of arsenic in aquifer material can be attributed to minerals from Asmari Formation. It appears
that a key mechanism for arsenic mobilizing to deep wells is microbial biodegradation of petroleum related organic matters
(PROMs), which exist in aquifer sediments and originates from the bedrock of the aquifer (Gachsaran Formation). This process
is followed by microbially mediated reductive dissolution of arsenic-bearing iron/manganese oxyhydroxides/oxides and further
by nickel and vanadium mobilizing to groundwater. According to hydrogeochemical conditions and cluster analysis, water wells
in Maydavood aquifer are divided to four subgroups: the wells with mildly reducing condition (subgroup I), moderately reducing
condition (subgroup II), reducing condition (subgroup III), and high reducing condition (subgroup IV). Affected wells to arsenic
are belonged to subgroups III and IV. |
| |
Keywords: | Iran Groundwater Arsenic Biodegradation Iron– manganese oxyhydroxides/oxides |
本文献已被 SpringerLink 等数据库收录! |
|