查看文章

Arsenic (As), ammonium‐nitrogen (N), nitrate‐N concentrations, and oxidation–reduction potential (ORP) in the water samples from the river, pond, dug well, and shallow and deep tube wells (TW) were investigated in a farming village of southwestern Bangladesh. Concentrations of As and ammonium‐N were the highest, whereas ORP was the lowest in the shallow TW water among the water sources. The ammonium‐N concentration correlated positively with the As concentration and negatively with ORP for all samples, irrespective of the water sources. A rise in the ammonium‐N concentration was hypothesized to enhance microbial activity, which in turn would lower ORP, and then As was released from sediments to the surrounding water in a reducing condition. The source of ammonium‐N in the shallow TW water was identified as N fertilizer, based on the δ¹⁵N analysis. Thus, the influence of N fertilizer …