Speciation of Sewage Derived Phosphorus in Coastal Sediments from Rio de Janeiro, Brazil

摘要

Phosphorus speciation was performed in sediments and waters from an area of 20 km~2 under the influence of untreated sewage released via a submarine outfall. Results showed that the pool of organic and non-apatite P made up the major fraction of sewage derived R A good correlation between P_(napat)( and Fe_(DBC) indicated that sorption on iron oxides is an important mechanism for removal of P to the sediments. Mass balances revealed that most of the sewage derived P had been exported from the observation area but, in spite of this, concentrations of labile forms of P reaching 1900 μg P g~(-1) were amongst the highest reported for polluted estuarine sediments. The supply over 20 yr of high nutrient loads would have been sufficient to produce 500 000 t of fixed carbon, of which 2% lies presently in the sediments of the surveyed area.