The studies on physico-chemical factors and phytoplankton at the 3 rivers in the Taejon city were conducted from November 1997 to May 1998. The Results were as follows; In the water quality, the down streams were generally worse than the upper streams. Water temperature was varied from 2.4℃ to 23.0℃; DO from 1.80㎎/ℓ to 17.6㎎/ℓ ; pH from 4.7 to 10.4 ; BOD from 0.78㎎/ℓ to 8.80㎎/ℓ; COD from 0.32㎎/ℓ to 8.26㎎/ℓ ; SS from 2.0㎎/ℓ to 43.0㎎/ℓ ; total phosphate was from 0.001㎎/ℓ to 0.709㎎/ℓ ; total nitrogen 0.01㎎/ℓto 11.69㎎/ℓ . In phytoplankton species, they were identified as total 191 taxa composed of 8 classes, 18 orders, 35 families, 74 genera, 152 species, 35 varieties and 4 forms. The dominant species were Synedra ulna in Taejon-chon, Diatoma vulgare in Yudong-chon, Oscillatoria princeps, Scenedesmus gadricauda, Synedra ulna, and Diatom vulgare in Gap-chon. Standing crops of phytoplankton were from 2,076 cells/㎖ to 97,356 cells/㎖.

This study estimate the degree of contamination in the streamwater around the Sudokwon landfill site. It was sampled at 10 sites in Jan., Apr., Jul. and Oct., 1996. There were analyzed five kinds of toxic chemical material-CN, ABS, PCB, As, Org-P, and four kinds of heavy metal-Pb, Hg, Cd, C_r^+6. The result are 1)The COD was generally increased to compare before landfill, 2)The Org-P and PCB were not detected at all points, 3)The concentrations of Pb, C_r^+6 and As were lower than the environmental criteria values, 4)The CN, Hg and Cd were over envirommental criteria values, and so emergent regulation is needed, 5)The effects of the streamwater contamination were not only the leachate of the landfill, but also the small factories and agricultural land around the landfill.