คุณภาพน้ำและความเหมาะสมต่อการใช้ประโยชน์ของน้ำผิวดิน ในแหล่งน้ำทะเลหลวง จังหวัดสุโขทัย

Abstract

The objectives of this research were to study general water quality and heavy metal
content of surface water in Thalaluang water resource, Sukhothai province and to compare
the water quality indicators and heavy metal content of the surface water between
sampling stations including sampling seasons. Besides, the suitability of the surface water for
multi proposes was evaluated. In this study, 7 water sampling points were determined for 4
representative zones of inlet, outlet, and inlet-outlet of the Thalaluang water resource and
in Thalaluang lake. The surface water samples were collected for 3 months of wet and dry
seasons. The results showed that pH, Temperature, DO, TDS, EC, Transparency, Turbidity and
Hardness of the surface water were 6.8-8.8, 26.4-38.1 ºC, 2.5-7.3 mg/l, 80-239 mg/l, 143-364
μS/cm, 11.0-50.0 cm, 23-299 NTU and 52-108 mg/l as CaCO3, respectively. Cd, Cu, Pb and Zn
in the water were 0.000-0.015, 0.013-0.247, 0.000-1.235 and 0.000-0.508 mg/l, respectively.
Temperature of surface water in wet season was slightly higher than that determined in
standard criteria for aquatic life. Averages DO of the water were high and proper for animal
life. Averages transparency of the water in wet seasons were low comparing with standard
criteria for aquatic life. pH values of the water were suitable for multi proposes. Cd of the
water in wet season and Pb of that in wet and dry season were higher than standard criteria
for surface water type 3, standard criteria for aquatic life and standard criteria for water
supply. Cu of the water in wet season were higher than standard criteria for surface water
type 3. Besides, Cu of the water in wet and dry season and Zn of that in wet season were
higher than standard criteria for aquatic life. Flowing of overland runoff through agricultural
area and urban area into the Thalaluang water resource was expected to be cause of
contamination of the heavy metals in surface water especially in wet season. The results
revealed that quality of surface water in the Thalaluang was low and heavy metals
concentration of surface water in the Thalaluang was high in wet season. These affected on
suitability of the surface water for multi propose. Then, monitoring of quality of surface
water in the Thalaluang should be continuously conducted. The monitoring data will be
useful for immediately detect and solve the problem that may occur.