Ecology, Environment and Conservation Paper

WATER QUALITY EVALUATION AND TOXIC PHYTOPLANKTON IN HUAY LUANG DAM RESERVOIR, UDON THANI PROVINCE, THAILAND

Sorrachat Thiamdao and Thanitsara Inthasotti

Abstract

The water quality and toxic phytoplankton in Huay Luang Dam Reservoir were studied. Samples were collected from 5 sites. This investigation was carried out from January to August 2015. Eleven physicochemical parameters were measured and were statistically analyzed using SPSS. The investigation revealed certain variations along the seasons. The clearest water was found during the cool-dry season. High levels of conductivity, TDS, salinity, ammonium-nitrogen were recorded in the summer and rainy season. On the other hand, nitrate nitrogen values measured in these water bodies decreased during these periods. After Bivariate analysis, a negative relation between nitrate nitrogen and ammonium nitrogen was found (p<0.01). The water quality was classified using the AARL-PC score. Three status of trophic levels were identified; Meso-Oligotrophic status (M-O), Mesotrophic status (M) and Meso-Eutrophic status (M-E). In the investigation of toxic phytoplankton, Microcystis wesenbergii Komárek and Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba Raju were observed. Moreover, C. raciborskii revealed a significant relationship with conductivity, nitrate nitrogen and soluble reactive phosphorus. Microcystin-LR levels in the reservoir were found to be present in small values.