Abstract
Lakes, due to the long residual period of influent, in addition to the sedimentation of contaminants, frequently have lower environmental quality standards than rivers and oceans, and rehabilitation can often be challenging. Moreover, lakes are sensitive to changes in watershed development and population growth, all causing environmental changes which can increase pollution load. The watershed of any given lake is crucial to the mitigation of sewage and contaminants and maintenance of clean water. This study focused on the sediment quality of five lakes differing in levels of water pollution control countermeasures such as sewerage system in their lake basins, and considered the relationship between the sediment characteristics and the watershed pollution loads. Nutrient salt concentration in surface sediments pore water was an effective indicator to estimate the release rate of the nutrients from the sediment. Relationship was observed between phosphorus load per lake surface area and phosphorus release rate, and it was thought that progress of water pollution control countermeasures would lower the phosphorus release rate from the sediment.
