Water Quality and Heavy Metal Monitoring of the Pong River in Northeast Thailand

Abstract

The Pong River is the largest basin located in the Northeast of Thailand. The river plays an important role as the water resource for agriculture, electricity generation, aquaculture, domestic uses, industrial and recreational purposes. Nowadays, the water quality of the Pong river has been changed and contaminated. This research aimed to study heavy metal monitoring in the water, and measuring water quality of the six different sites along the Pong River in three different seasons including summer(March 2016), rainy(August 2016) and winter(January 2017) in Khon Kaen Province, Thailand. The results revealed that cage fish farming and seasons affected the change of water quality. Most of the water quality parameters from all the three seasons did not exceed the defined surface water quality standards, except the Biochemical Oxygen Demand (BOD) of 3.55-4.48 mg/L which was over the standard value for most stations, possibly due to the accumulation of fish food and fish feces remained in the water. The heavy metals measured in the water in each station were Zinc (Zn), Lead (Pb), Copper (Cu), Cadmium (Cd), and Mercury (Hg). It was found that the levels of Zn and Cu exceeded the standard values of surface water quality owning to heavy metal accumulation in the sediment from cage fish farming. In addition, while the defined surface water quality standard values for Pb, Cd and Hg must not be over 0.05 mg/L, 0.005 mg/L, and 0.002 mg/L, respectively,     The highest levels of Pb, Cd, and Hg found were 0.1530 mg/L, 0.0586 mg/L, and 0.0079 mg/L respectively. Keywords: water quality; heavy metal ; monitoring ; Pong river ;Thailand