The hydrogeochemistry of pond and rice field recharge : implications for the arsenic contaminated aquifers in Bangladesh

[摘要] (cont.) The labile organic carbon in the pond recharge stimulates microbial respiration that mobilizes sediment-bound arsenic, contributing dissolved arsenic to the aquifers. Conversely, rice-field recharge does not mobilize arsenic. In fact, rice fields act as an arsenic sink. Irrigation moves arsenic-rich groundwater from the aquifers and deposits it on the rice fields. Most of the deposited arsenic does not return to the aquifers; it is sorbed by the field;;s surface soil and bunds, and is swept away in the monsoon floods. The results demonstrate how land-use changes in Bangladesh have impacted groundwater arsenic concentrations.

[发布机构] Massachusetts Institute of Technology