In this study, the water quality components (pH, BOD, COD, TOC, SS, DO, TP) and the water quality, observed for 10 years (2008~2017) in the five tributaries of the Nakdong River with the highest flow rates, were analyzed. Monthly levels of the water quality components were estimated and regression functions were used to quantitatively explain the changes in the BOD and COD components, with respect to the TOC components. The results of analyzing the water quality levels in terms of the living environmental standards show that the lowest water quality was observed midstream (ST-3) and the highest water quality was observed upstream (ST-1 and ST-2). The regression function was estimated to be a linear function in all five tributaries, and the goodness of fit of the function was high upstream (ST-2), midstream (ST-3), and downstream (ST-4). According to the regression analysis using the observation data from 2008~2017, we found that the consumption of dissolved oxygen increased with an increase in organic matter in the major tributaries of the Nakdong River.

Abstract
 1. 서 론
 2. 연구 방법
 3. 결과 및 고찰
  3.1. 낙동강 주요 지류에서 생활환경 기준 수질 성분의월 변동 분석
  3.2. 생활환경 기준 수질 성분별 수질등급 분석
  3.3. 낙동강 주요 지류에서 TOC, BOD, COD 성분의회귀분석
 5. 결 론
 REFERENCES

• 강동환(부경대학교 환경연구소) | Dong-hwan Kang (Environmental Research Institute, Pukyong National University)
• 소윤환(부경대학교 환경연구소) | Yoon-hwan So (Environmental Research Institute, Pukyong National University)
• 박경덕(부경대학교 마린융합디자인협동과정) | Kyeong-deok Park (Interdisciplinary Program of Marine Convergence Design, Pukyong National University)
• 김일규(부경대학교 환경공학과) | Il-kyu Kim (Department of Environmental Engineering, Pukyong National University)
• 김병우(한국수자원공사 K-water연구원 물순환연구소) | Byung-Woo Kim (Water Resources Research Center, K-water Research Institute, Korea Water Resources Corporation) Corresponding author