In this project, we investigate the sea areas from Kawing River in Taoyen County to Na-O River in I-lan County which include 37 water quality monitoring stations. The results of water quality monitoring show that the pH value, BOD, Coliforms meet the first and second class set by EPA in Taiwan. Besides, the concentration of most of nutrients and heavy metal also below the method of detecting （MLD）. According to the monitoring data show that the characteristics of marginal sea in Taoyen County, Keelung City , I-lan County can affect the variations of water quality especially in Taoyen County has the greatest variation. The analysis of dredge materials show that in Taoyen County, and I-lan County are the grain sands and Keelung City grit sand.

Northern sea area monitoring,nutrients, heavy metal,temperature outfall,nuclear power plant