Measurements of kidney, liver, lung along with blood trace metal levels were obtained in 20 exposed and 40 control cattle. The level of cadmium, mercury and arsenic were the highest in the kidney while copper, lead and zinc concentrations were the highest in the liver. Statistically significant correlation between the kidney and the liver were found for cadmium, copper, zinc, mercury and arsenic. No significant differences were observed between the area, sex and age in this study. The levels found were generally within the ranges compared with those found in similar studies in and outside.

This paper is examine the mutagenic activities of the water samples from Chun-gye and Joong-rang streams in March, 1968. For this examination, adsorbed of mutagens by 'blue cotton' and Ames method using Salmonella typhimurium was used. The results were as follow; 1. The average revertant colonies of the Chun-gye stream on TA 98 was 120/plate and TA 100 was 267/plate. 2. The average revertant colonies of the Joong-rang stream on TA 98 was l06/plate and TA 100 was 407/plate. 3. Chun-gye and Joong-range streams showed about the same mutagenic activities. 4. The mutagenic activity of treated sewage was higher than of untreated sewage. It is considered that, among the influent materials with Zimpro oxidation fluid, human feces and urine increased mutagenic activities.

The incidence of Sexually Transmitted Disease has risen despite the progress in its diagnosis and treatment methods. For the effective control programs of S.T.D it should be required medical and social approaches. This survey was conducted in Young Dung Po and Sung Buk areas from June, 1986 to September, 1986. The 1185 prostitutes were studies in order to determine the prevalences of sexually transmitted disease. The results were as follows: 1. The average age of prostitutes was $24.0\pm3.9$ years. The age group of 21-25 years old was the highest level of about $70.3\%$. 2. The positive rate on non Gonococcal urethites was $9.1\%$ at Sung Buk area and $15.3\%$ at Young Dung Po area. 3. The positive rate of Neisseria Gonorrhoeae on culture of TM media was $6.4\%$ or total level and incidence ratio of Neisseria Gonorrhoeae: Non Gonococcal urethritis was 1: 1.7. 4. The positive rate of PPNG was occupied about $26.3\%$ among the total NG positive case. 5. The positive rate of VDRL Slide Test was $2.9\%$, and antibody Titer level of 1:2 was $38.8\%$. it was the highest of all Titer distribution.

The genus Vibrio contains some of the most important intestinal pathogens of humans, including Vibrio cholerae, the cause of epidemic Asiatic cholera. A group of organisms which have been reffered to as the non-agglutinating vibrio (NAG) do not agglutinate in the Vibrio cholerae 0 group 1 antisera, but are indistinguishable from the 0-1 group both chemically and genetically. Non-O-l Vibrio cholerae can cause isolated as well as focal outbreaks of diarrhea, but the volume of fluid loss does not approach that of classic cholera, and the disease is usually self-limiting. These free-living organisms are found world-widely distributed in the environment including sewage, contaminated water, estuaries, seafood and animals. These strains involved in several cases were isolated from the environment and some patients of diarrhea, and a few epidemiologic reports indicated the wide distribution of the strains throughout the country, giving an attention to the role the organisms may play in an outbreak of diarrhea in Korea. More research on the epidemiology, serologic typing and virulence of the group of organisms, should be, therefore, done to obtain a complete understanding of their role in human disease.

Due to the increase of population and development of industry, the demand of available water resources increased . Many reservoirs have been constructed in large scales to meet this urgent need , resulting in the increased amount of water resources. After the constructions, however, serious pollution-especially eutrophication-in some reservoirs become a socialaffair. Therefore, water quality control in these resources should be considered more intensively than any other environmental preservation policies. It also seems to be imminent to prepare the precautionary steps. Most water pollution in Korea-73 percent - can be traced to domestic sewage. It may rome as a surprise to Some, Industry is responsible for just 27 percent of ]Korea's water pollution. What he calls 'non-point' Sources, which may include agricultural Chemicals, Create only negligible amount of water pollution. Up to $15\%$ of domestic sewage is treated in Korea, which is quite low when compared with the waste processing in developed countries. So it is the most urgent matter to control the pollution sources. One of the precautionary plans, more urban domestic sewage treatment plants must be installed and operated efficiently. It is known that nutrients such as nitrogen and phosphorous are the major factors the process of eutrophication, which can be removed majorly by the tertiary or advanced treatment process.