Evaluation of water quality in bang khen mai canal using analysis of variance

Abstract

This research aimed to study the causes of changes in water quality and compare the water quality in Khlong Bang Khen Mai when the seasons and sampling points are different. These factors may cause a change in water quality. A total 50 of water samples were collected from 5 sampling points, each point approximately 300 meters apart, for a total distance of 1.5 kilometers. They cover three seasons such as winter (October 2020 to February 2021), summer (March to May 2021), and rainy (June and July 2021). Three parameters of this research which consist of both the chemical and physical quality parameters are pH, Dissolved Oxygen (DO), and Electrical Conductivity (EC). The result shows that the average pH has ranged from 7.10 - 7.74, the dissolved oxygen (DO) was in 1.80 - 2.84 mg/L, and the electrical conductivity (EC) was in the range of 327 - 517 μs/cm. A two-way analysis of variance is a statistical method used to compare the water quality in Khlong Bang Khen Mai. The results indicate that the test differences between seasons affected the change in water quality in all parameters with a statistically significant level of 0.05. Afterward, the comparison of multiple comparisons by Scheffe's method showed that the pH and dissolved oxygen (DO) in the rainy season were significantly different from winter and summer at the level of 0.05. For the electrical conductivity (EC), there was significant differences between summer and winter at the 0.05 level.