ANALYSIS AND ASSESSMENT OF ARSENIC POLLUTION IN GROUND WATER IN THE CAT TIEN DISTRICT OF THE LAM DONG PROVINCE

Abstract

    Assessments of arsenic pollution in water in the Cat Tien district of the Lam Đong provincehave been carried out during the period of 2013-2014. In 37 samples of surface water anddug well water, the arsenic pollution levels ranged from 0 to 5ppb, For 29 samples of water ofdrilling wells, 8 water samples had arsenic level being higher than QCVN 01: 2009/BYTallowed limit. With two drilling well samples collected from Cat Tien commune (CT_TT 04)and Gia Vien commune (CT_GV 03), the arsenic level of them were about 10 times higherthan QCVN 01: 2009/BYT allowed limit. Especially, the arsenic level of the drilling wellcollected from Tu Nghia commune (CT_TN 04) was about 45 times higher than Vietnamesestandard allowed limit.These drilling wells, which have arsenic pollution, have the Eh levels often negative (-Eh), theEh values of the drilling wells saimples ranged from (-1.4) to (-186). In the drilling wells ofGia Vien commune and Cat Tien town showed that the high level of arsenic contaminationparallel with the ammonium pollution levels. When the Eh was negative (-Eh), theconcentration of As (III) has higher percentage compared to As (V), and with the iron ions,the Fe2+ ionic concentration always occupies a larger amount compared to Fe3+ ionicconcentration.

Keywords: Arsenic pollution, ground water, As(III)/As(V), ammonium, Cat Tien