Assessing Salinization and Water Quality in Koh Kong Coastal Areas of Cambodia: Potential Impacts of Climate Change

Salination and saltwater intrusion are common and increasing problems in coastal areas. This study investigates the susceptibility of soils and water resources to saline intrusion in the coastal areas of Cambodia in the context of climate change. Water samples were collected from tube wells (n = 8), dug wells (n = 25), canals (n = 7), ponds (n = 5), and rain water (n = 5) across the Koh Kong coastal area of Cambodia and measured for the contaminants of health concerns (As, Ba, NO₃⁻, NO₂⁻, F⁻, and Mn) and esthetic quality (Cu, Fe, and Zn) following USEPA methods. Water salinity and other physicochemical properties (Temperature, pH, ORP, conductivity, TDS, turbidity, and DO) were measured onsite using field instruments. Concurrently, surface agricultural soils were sampled at each site. Soil salinity was determined by soil/water extract method following a standard protocol. Analytical results revealed that approximately 12.5% of tube wells, 4% of dug wells, and 20% ponds were saline. Concurrently, 37.5% of tube wells and 58.4% of dug wells contained As greater than 10 μg L⁻¹, exceeded WHO’s Drinking Water Quality Guideline. Geogenic barium, iron, and manganese groundwater contamination also was widespread regionally. Anthropogenic contaminants like nitrate and nitrate (from agricultural runoff) were lower, well Cambodian Drinking Water Quality Standards. Most of soil pH was in acidic condition. Most of agricultural soils in Koh Kong coastal area are not saline, but the agricultural fields close to coastline and/or in the estuarine are frequently saline. This study suggested that appropriate water treatment technologies are needed to provide safe drinking water to people residing in Koh Kong coastal areas, and that it is important to manage salinity to prevent future contamination. Moreover, adaptation actions should be further promoted in order to cope with the potential impacts of the climate change in this Koh Kong coastal area.