Bacteriological Quality of Sea Water in Deukryang Bay, Korea

득량만 해수의 세균학적 수질

A bacteriological study of sea water in Deukryang Bay was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria for the designated area of shellfish cultivation. Sea water samples were collected at the established sampling stations (fig. 1) from May 1995 to November 1996. During the study period, coliform group, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. Coliform group and feral coliform MPN's were ranged from $<\;3.0\~4600/100m{\ell}\;and\;<\;30\~1,100/100m{\ell}$, respectively. The bacteriological criteria of sea water in shellfish growing area should be less than 70 per l00ml of sea water for median value of coliform MPN, and below $10\%$ of the samples which contain over than 230 for coliform MPN or over than 43 for fecal coliform MPN, Most of the waters from 26 sampling stations were complied water coliform criteria recommended for designated shellfish growing area. Then, the ratios of the samples with move than 230/10ml of coliform group MPN and more than 43/100ml of fecal coliform MPN were $7.4\%$ and $8.5\%$, respectively. The bacterial density of the sea water was deeply affected by rainfall amount. For example, coliform bacterial counts of sea watery after 48 hours from 93 mm rainfall were $6\~7$ times higher than those of without rainfall. During the study period, infectious bacteria such as Vibrio cholerae, Salmonella sp. an d Shigella sp. were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnificus were $15\~20\%$ in summer months.

득량만 해수에 대한 세균학적 수질을 평가하여 수출용 패류생산지정 해역수질에 합당한가를 파악함과 동시에 지표세균의 조성, 병원성 세균등을 조사한 결과를 요약하면 다음과 같다. 1. 득량만 해수의 세균학적 수질은 만 안쪽의 연동지선의 일부해역 (area IV)을 제외하고는 수출용패류의 생산해역의 수질기준에 합당하였다. 2. 대장균군의 최확수는 해수 100ml당 <\;3.0\~4600$의 범위였으며 230을 초과하는 시료의 비율은 $7.4\%$였고, 분변계대장균의 최확수는 $<\;30\~1,100$의 범위였으며 43을 초과하는 시료의 비율은 $8.5\%$로 한계치 $10\%$에 미달하였다. 3. 강우시에는 비강우시에 비하여 세균 오염도가 높았으며 특히 93mm의 강우가 있은 48시간 이후에도 비강우시의 $6\~7$배나 높은 세균오염도를 나타내었다. 4. 대장균군의 분류결과 Escherichia coli가 약 $54\%$나 되어 오염원의 주류가 분변오염임을 알 수 있었다 5. 살모넬라, 시겔라, 콜레라균 등 수인성 병원세균은 검출되지 않았다. 6. 병원성 비브리오균은 여름철인 $6\~8$월 사이에는 시료의 $15\~20\%$에서 양성으로 나타났다.