Evaluation of arsen in surface water and groundwater layers in the Cat Tien district of the Lam Dong province

Abstract

Evaluation of arsenic pollution in surface water and groundwarter layers in the Cát Tiên district of the Lam Dong province has been carried out during the period of 2013–2015. Arsenic concentrations of 37 samples of surface water and dug well water ranged from 0 to 5 ppb. 9/29 water samples drilling wells of the Quaternary groundwater layer had arsenic concentrations higher than those of the standard QCVN01:2009/BYT. The arsenic concentration of samples collected from the Cat Tien commune (CT-TT 04) and the Gia Vien commune (CT-GV 03) was about 10 times higher than that of the standard QCVN 01:2009/BYT. Especially, the arsenic concentration of the drilling well from Tu Nghia communes (CT-TN 04) was about 45 times higher than the standard QCVN 01:2009/BYT. Drilling wells with arsenic pollution had the Eh range from -1.4 mV to -186 mV. The concentrations of arsenic and ammonium of drilling wells in Gia Vien and Cat Tien commune were high. The concentrations of As³⁺and Fe²⁺ were higher than those of As⁵⁺ and Fe³⁺, respectively.