South Korea's Han River Basin (IMAGE) Portland State University Caption A new Portland State University study shows that even though water quality has improved in South Korea's Han River basin since the 1990s, there are still higher-than-acceptable levels of pollutants in some of the more urbanized regions in and around the capital Seoul. Credit Courtesy of Heejun Chang Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.