This study was conducted to investigate the effects of environmental factors such as temperature, salinity, pH, and UV light on the survival of life-threatening Vibrio vulnificus. In the temperature range of 15 to 25℃, the numbers of V. vulnificus increased during the 6-day incubation, but outside this range, the survival of V. vulnificus was poor. Incubation between 1 and 10℃ showed that V. vulnificus survived poorly below 10℃. At salinities between 5 and 25ppt, the numbers of V. vulnificus increased or remained unchanged for 6-day. At salinities above this range, the numbers of V. vulnificus decreased. The optimal pH range was 6.5 to 8.0 and outside this range, the survival ratio of V. vulnificus was small. At 15 and 25℃, UV radiation was bactericidal for cultures of V. vulnificus. The counts of V. vulnificus were reduced approximately 10,000-fold after 2h of UV light treatment at both temperatures. Above results showed that environmental factors were effective on the survival of V. vulnificus in the environment.

First, We classified man-made lakes in Korea as 4-type lakes, that is, there were River-run lakes, Dentritic lakes, Reservoir-lakes, River-mouth lakes, We studied on the environmental factors of 3-type lakes except River-mouth lakes, compared these lakes with natural lakes in foreign country. Environmental factors were watershed area, lake storage, mean depth, hydraulic retention time. As a results, 3-type lakes in Korea had remarkable differences one another according to above-mentioned environmental factors. First, We recognized that River-run lakes had higher nutrient loading according to having wider watershed area than natural lakes, and had lower algal growth rate according to shorter hydraulic retention time than natural lakes. Dendritic lake had higher nutrient loading than natural lakes, longer retention time than River-run lake. Reservoir-lakes had environmental factors between Dentritic lakes and River-run lakes. Therefore, If this studies had no quantitative results about various factors, We recognized that man-made lakes in korea had different environmantal factors as compared with natural lakes, and had clear classification among 3-type lakes.