Long Term Monitoring for the Control of Cyanobacterial Blooms in Lake Uiam

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Research article

Journal of the Korean Society for Environmental Analysis 2016;19(2):109-118.

의암호 남조류 발생 제어를 위한 수질 장기모니터링 및 환경요인 분석

이석종¹, 허인량¹, 임병찬¹, 이건호¹, 정원구², 허범녕²

¹강원도 보건환경연구원
²강원도보건환경연구원

Abstract

We monitored the water quality and algal communities to analyze the environmental factors that contributed to the development of cyanobacterial blooms in lake Uiam from 2012 to 2015. Anabaena species were isolated as the dominant type of cyanobacteria in the lake, and these were first observed at sites S6~S9 from June to July. The total phosphorus (T-P) concentration was estimated at 0.015 mg/L in 2015 and 0.043 mg/L in 2011, which represents a reduction of 65%. Hence, the N/P ratios in the lake also changed, i.e., the ratios were 110~130 in 2014~2015, and 40~70 in 2010~2013. The daily loads of T-P were reduced 5.3 kg/d and 8.8 kg/ d in 2014 and 2015, respectively, which were better loading rates than the value of 23.0 kg/d and 16.6 kg/d in 2012 and 2013, respectively. Algae blooms did not occur in Lake Uiam during 2014 to 2015. According to our analysis of critical environmental conditions, blooms will readily occur when N/P ratios are 20~30 and water temperatures are maintained at 20~25°C over a period of 30 days; moreover, 50~60 mm of precipitation is needed from the middle of June to early July.

Key Words: Cyanobacterial bloom, Uiam lake, Load amounts of pollutants, Optimum N/P ratio