Determining overall water quality related to anthropogenic influences across freshwater systems of Thailand

Abstract

Overall water quality in the 48 rivers of Thailand in 2009–2017 was determined using time series and water quality index models. Water quality degradation was mainly caused by high faecal coliform bacteria (FCB) and suspended solids in the North; high nitrate-nitrogen and total phosphorus in the Northeast; and high biochemical oxygen demand and FCB, and low dissolved oxygen in the Central Plains. FCB was a major parameter affecting water quality in the East, the West, and the South. High correlations among water quality and land use variables were detected. Management guidelines are provided to improve overall water quality.