Water Quality Monitoring in Chao Phraya River

Abstract

            Water Quality Monitoring in Chao Phraya River was conducted in 2011; 18 sampling stations from the estuary in Samutprakarn Province to the upstream in Nakornsawan Province. This research divided  the river into 3 sections: 1) Lower Chaophraya from Pra Samut Chedi in Samutprakarn Province to Rama 7th Bridge in Bangkrouy, Nonthaburi Province, 2) Central Chaophraya from Nonthaburi Bridge, Amphoe Muang, Nonthaburi Province to Pom Petch, Panancheng Temple, Amphoe Pranakornsriayuthaya, Pranakornsriayuthaya Province , and 3) Upper Chaophraya from Chaophraya Crossing Bridge, Amphoe Muang, Angthong Province to Dechatiwong Bridge, Nakornsawan Province. The sampling covered 3 seasons; twice in summer, once in rainy season, and once in winter. Water samples were analyzed in the Regional Environmental Office 6 Laboratory. Chemical parameters were Dissolved Oxygen, Biological Oxygen Demand,  and Ammonia. Biological parameters were Total Coliform  Bacteria and Fecal Coliform Bacteria.

            Results of water quality analysis  were shown that 78% of the river did not meet the Surface Water Quality Standards. Only 22% met their classification. None had the higher water quality than the standards. Hypothesis of water quality - distance - season correlations were tested. Statistical analysis One – way ANOVA at 0.05 level of significance showed that water quality was not affected by seasonal variation but affected by distances as the water flows through each section according to the Chaophraya River Classification by Pollution Control Department. Another Hypothesis of water quality between the great flood in 2011 and the same period in 2010 were also tested. Statistical analysis Paired Samples t – Test at 0.05 level of significance showed that the great flood did not affect water quality of the whole Chaophraya River. However, Dissolved Oxygen was affected during winter in the lower section between the sampling station CH01 to CH15 (Pra Samut Chedi in Samutprakarn Province to Nonthaburi Bridge in Nonthaburi Province)