Lm. Nguyen et al., PHOSPHORUS RETENTION AND RELEASE CHARACTERISTICS OF SEWAGE-IMPACTED WETLAND SEDIMENTS, Water, air and soil pollution, 100(1-2), 1997, pp. 163-179
Sediment deposited in traps positioned along a sewage-impacted wetland
receiving phosphorus (P)-retaining reactants from natural wetland wat
er was fractionated into different particle sizes, and the amount of P
retained in these particle sizes was investigated. Subsamples of the
sediments collected from different sites along the wetland system were
also equilibrated with water at different water:sediment ratios and e
quilibration periods to investigate the extent of P released from thes
e sediments under aerobic and anaerobic conditions. Results obtained s
howed that most of P deposited in sediments is in fine fractions (<16
mu m), particularly in sediments collected from confluence sites where
water inflow from the natural wetland provides P-retaining reactants
and from sites immediately below these confluence sites (postconfluenc
e sites). The extent of P release from sediments depended on the aerob
ic anaerobic conditions of the sediments, equilibration period, water:
sediment ratio and the position of sites within the wetland. The rate
of P released from sediments associated with an increase in equilibrat
ion period tended to be higher under aerobic than anaerobic conditions
. Water:sediment ratio was found to be a more important factor in cont
rolling the release of P from sediments under anaerobic than aerobic c
onditions. The amount of P released from the confluence and postconflu
ence sites was higher than that from other sites over a range of equil
ibration periods and water:sediment ratios under aerobic and anaerobic
conditions.