Groundwater Arsenic Contamination Status In Dhakuakhana Sub-Division of Lakhimpur District, Assam, India

摘要

The present work describes the occurrence and distribution of arsenic and iron in six Gaon Panchayat of Dhakuakhana sub-division of Lakhimpur district, Assam. The focus of the study is on rural areas because of the difficulties associated with applying mitigation measures in scattered rural communities. No detailed analysis of the water quality of the selected sources with respect to arsenic and iron had been undertaken before. Thirty groundwater samples were collected from tubewells and ringwells at different sites from Dhakuakhana sub-division during dry season (February, 2011 – March, 2011). Arsenic was analysed by using an atomic absorption spectrometer as per the standard procedures. Iron was measured by 1, 10-phenanthroline method using a UV-visible spectrophometer. It is observed that a sizeable number of groundwater samples contain arsenic and iron at a toxic level. Statistical observations also show that arsenic in groundwater exhibit nonuniform distribution with a long asymmetric tail on the right of the median. We ran one population t-test to compare the concentrations of arsenic among the sampling sites and used an alpha level of 0.05 and considered differences to be significant if P ≤ 0.05. The present study has shown that naturally occurring arsenic in groundwater is more widespread in the study area than is generally recognized and that, with continuous testing, more contaminated groundwater aquifers are bound to be identified.