The study looked at water quality in highland agricultural areas in the Nakdong River basin. They found that runoff from these areas had high levels of pollutants like BOD, COD, T-N, and T-P, exceeding safe levels for agricultural use. The pollutants were likely from fertilizers washed into the soil during rain, leading to contamination of nearby rivers. The study also showed that pollution loads from agricultural fields were much higher than from forested areas, indicating a need for better farming practices to prevent further contamination.