การแพร่กระจายของฟอสฟอรัสรูปแบบต่าง ๆ ในดินตะกอนชายฝั่งทะเลตะวันออก

Abstract

Total P and the chemical forms were investigated in coastal marine sediments of the Eastern Coast of Thailand in the dry (April 2001) and wet (July 2001) seasons. The amounts of total P ranged from 55.83 to 2,575.83 and from 30.0 to 2672.50 ug g-1 dry sediment for the dry and wet seasons, respectively. The sediments mainly consisted of inorganic than organic P. Sediment inorganic P fractions were determined by a sequential extraction. In riverine sediments, the major form of P was Fe, Al-bound P and the second was organic P, whereas other locations showed different relative dominant P forms. Seasonal changes had an influence on P fractions being available. In the dry season the available fractions derived from organic P whereas those in the wet season were derived largely from Fe, Al-bound P. Release of P from Fe, Al-bound P was mainly from amorphous Mn oxides rather than from Fe oxides.In this study Fe oxides were the major P sorbent of the sediments by clay contents, while organic matter and CaCO3 were less effective in P sorbing. In addition sediment P concentrations decreased with increasing sediment pH and salinity of the overlying water.