Using microorganisms to assess water quality is not new. It is new in surface waters of South Korea. South Korea is a densely populated, geographically small peninsula that receives a scant 127 cm of rainfall each year. This water is stored in a myriad of reservoirs and rivers that flow through heavily urbanized city centers, well fertilized croplands, and steep, forested hillsides. Monitoring and maintaining surface water quality, with a high percentage of this water being stored for drinking, is therefore, of paramount concern to all South Korean citizens. Using microorganisms can be a very time- and cost-effective way to detect important changes in water quality over time.
The basic premise of this work is to use phytoplankton genera to assess changing concentrations of important chemical parameters. Knowledge of the chemical and environmental tolerances of microorganisms is well published in the literature. Using a 20 micron plankton net and industry-standard sampling methods, water samples were collected from three different water bodies: (1) the Han River flowing through Seoul, (2) the Tancheon River, a tributary to the Han, and (3) Daecheongho Lake, a remote drinking water reservoir. Water quality was assessed using the National Sanitation Foundation’s Water Quality Index.
Results/Conclusions
Certain water quality parameters, especially nutrients and dissolved oxygen, were significantly different within the three sampled water bodies. Phytoplankton genera were correspondingly different, indicating that, indeed, phytoplankton could be used to predict certain water chemistry traits. Specifically, the Han had relatively low nutrients and high dissolved oxygen levels and was dominated by the Anabaena, Eudorina, Pediastrum genera of phytoplankton. The Tancheon had the highest concentrations of nutrients and conductivity levels, and was dominated by Navicula, Melosira, Cyclotella genera of phytoplankton. Finally, the Daecheongho Reservoir was the cleanest water with nutrients below detection levels, and contained predominantly Fragilaria, Oscillatoria, Staurastrum genera. These findings compare favorably with similar studies found in the literature.
With nutrient pollution of surface waters becoming an ever-growing global concern, water quality studies that can lead to faster remedial action and better pollution prevention are critical to keeping South Korean surface and drinking waters clean. Parts of the Daecheongho Reservoir are already experiencing massive Microcystis algal blooms which could soon affect the entire reservoir. The findings from this study will be further developed to include additional water bodies in South Korea, and to assist agencies and organizations in their water quality planning efforts.