Sources and Mechanisms of Groundwater Contamination Due to Arsenic : a Case Study in Hanoi City
Year: 2004
Type: article
Abstract: To identify the source and mechanism of arsenic contamination, groundwater and sediment samples were taken from the well fields for municipal water supply in Hanoi City.Groundwaters in the south zone were anaerobic and contained high levels of arsenic, ammonia, organic matter and iron.DOC, ammonia and phosphorus showed better correlations with arsenic in groundwaters than iron with arsenic.The iron contents in the sediment samples collected from four boreholes fell in a narrow range between 2.5 and 5.0 percent, whereas the arsenic contents varied significantly between <lllg/g and 22Ilg/g.All but two soil samples with high arsenic contents (>10 Ilg-As/g-dry soil) were obtained from the peat layers.Sediments taken from the contaminated aquifer contained higher arsenic than the sediments obtained from the clean aquifer.Although solid-phase arsenic bound to ferric oxyhydroxide was more abundant than organic-bound arsenic, most of the arsenic in groundwaters was estimated to be leached from peat organic matter based on batch As-leaching experiments and the AslN ratios in the sediments and in groundwaters.Detection of pollens of arsenic-hyperaccumulating fern species and mangrove species suggested that arsenic was concentrated by the ancient fern species and mangrove ecosystems and subsequently buried in the sediment.
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2553299080