Monitoring of faecal indicator bacteria at the recreational beaches of South Korea

The densities of Enterococcus, Escherichia coli and total coliform bacteria at the beach sand, swash zone, and the waist-high marine water were monitored using Enterolert registered and Colilert registered -18 kits (IDEXX Laboratories Inc., Westbrook, Maine) at the Gyeongpo and the Jumunjin recreational beaches of the eastern coast of Korea. The samples were collected weekly from July 19, 2011 to Aug. 30, 2011. The densities of Enterococcus and total coliform bacteria were the highest in the beach sand. The density of Escherichia coli was the highest in the swash zone. The frequencies above the U.S. EPA single-sample criteria were 29 at the Gyeongpo beach and 16 at the Jumunjin beach among the 42 samples of swash zone and marine water. The densities of faecal indicator bacteria were higher in the swash zone than the marine water. The beach sand may play as a bacteria reservoir of marine water. Regular monitoring of faecal indicator bacteria in beach sand is necessary during the beach opening. Alarming about the level of faecal contamination of the beach sand will be an important health problem. The guidelines of faecal indicator bacteria in beach sand should be made for the purpose of beach health.