3:30 PM - 4:45 PM
[AHW16-P11] Evaluation of the source and bioavailability of particulate phosphorus in Yasu River by using sequential extraction methods
Keywords:particulate phosphorus, sequential extraction, bioavailability, Lake Biwa
River water samples were collected from 5 sites in Yasu river once or twice a week from April 2015 to May 2015. Drainage from paddy fields were collected from Koka city, where locates in middle part of Yasu river watershed once a month between May and July. Furthermore, river water samples after rainfall event were collected from 10 rivers flowing into Lake Biwa on September 2015. After sampling, we separated several fractions of PP from suspended solids by sequential extraction methods (1M ammonium chloride, 0.11M bicarbonate dithionite, 1M NaOH, 0.5M HCl extraction) in water sample. In this method, PO4-P is extracted from the particle fraction with high bioavailability in sequence. PO4-P extracted from the particle fraction was determined by the molybdenum-blue method.