Improved water quality in response to pollution control measures at Masan Bay, Korea

► Pollutant abatement policy first exampled in highly developed coastal area of Korea. ► Land–sea pollutant interaction addressed by six-year systematic monitoring effort. ► Reduction of land-based pollutants successfully achieved by point sources control. ► Time-lagged water quality response supported seawater residence time of ∼1month. The total pollution load management system (TPLMS) was first applied in 2007 to the highly developed Masan Bay watershed, Korea. To evaluate the effect of TPLMS on water quality improvement, we analyzed the water qualities in rivers and bay during 2005–2010, targeting chemical oxygen demand (COD), suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) loads. Land-based pollutant loading all decreased during this period, with a significant reduction in COD and SS loads (p