| Although a variety of measures are taken to address a lake eutrophication-problem, only around 50% of the target lakes currently meet the water quality environmental standard in Japan. According to reported studies, the water quality in shallow lake is much affected by stirring sediments up due to strong winds. In this study, two dissolution tests were conducted in 2013 and 2016 using the bottom sediment of Lake Kasumigaura to evaluate the impact of other factors on water quality. The bottom sediments were sampled after the wind velocity had been low more than one week.It showed that the PO4-P and NH4-N dissolution rates under anaerobic condition in 2016 were lower than those in 2013. In addition, the concentration of CDB-P (Citrate-Dithionite-Bicarbonate extractable phosphorus) contained in the sediment in 2016 was lower than that in 2013, whereas the dissolution rates of Fe and Al under aerobic condition in 2016 were lower than those in 2013. |
