Natural attenuation processes for remadiation of arsenic contaminated groundwater in a village of hashtrood city, Iran

Arsenic contamination of groundwater in one of the villages in Hashtrood city in Iran causes skin lesions for its people. Natural attenuation (NA) of As-contaminated groundwater may be a cost effective in situ remedial option. It relies on the site intrinsic assimilative capacity and allows in-place clean-up. In this paper, natural attenuation feasibility of As contaminated groundwater in this village, with regard to its conditions such as plant cover, minerals type, and hydrological characteristics has been studied. Sorption to solid phases is the principal mechanism removing As from ground water. Hydroxides of Iron, aluminum and manganese, clay and sulfide minerals, and natural organic matter has been shown to be significant As adsorbents. The extent of sorption is influenced by As speciation and the site geochemical conditions such as pH, redox potential, and the co-occurring ions. Microbial activity may catalyze the transformation of As species, or mediate redox reactions thus influencing As mobility. Plants those are capable of hyperaccumulating As may translocate As from contaminated groundwater to their tissues, providing the basis for phytoremediaion. However, NA is subject to hydrological changes and may take substantial periods of time, thus requiring long-term monitoring. Sufficient site characterization is important to the success of NA. Further research is required to present mathematical model to predict the fate and transport of as and to evaluate the site NA capacity. Engineering enhanced NA using different environmentally products may be an effective alternative.

کلیدواژه ها:

Arsenic ، Natural Attenuation ، Hyperaccumulation