The significance of iron and manganese in the phosphorus immobilization into sediments of the Prut and Dniester Rivers (Republic of Moldova)

The interdependence of phosphorus content with iron and manganese concentration in
sediments of the Prut and Dniester Rivers was established. The methodology of sampling in
accordance with recommendations of the American Geological Agency was used. The Fe and
Mn content was determined by the flame atomic absorption spectroscopy. In order to establish
the phosphorus content in water, bottom sediments and its interstitial water the methodology
and procedures recommended by World Health Organization were applied.
The recorded ratio of total iron and phosphorus at sediments surface along the Prut and
Dniester Rivers was, in the most cases, greater than 15. This fact indicates that in sediments
there is enough iron to control the flux of phosphorus from sediments in the water horizon. In
interstitial water the Fediss:o-P ratio was greater than 3.6, suggesting that the sediments have
a high affinity to phosphates, immobilized its.
In bottom sediments of the Prut and Dniester Rivers the manganese and iron content has
correlated positively with the phosphorus forms amount.