SPECIATION OF SEWAGE DERIVED PHOSPHORUS IN COASTAL SEDIMENTS FROM RIO-DE-JANEIRO, BRAZIL

Phosphorus speciation was performed in sediments and waters from an ar ea of 20 km(2) under the influence of untreated sewage released via a submarine outfall. Results showed that the pool of organic and non-apa tite P made up the major fraction of sewage derived P.A good correlati on between P-napat and Fe-DBC indicated that sorption on iron oxides i s an important mechanism for removal of P to the sediments. Mass balan ces revealed that most of the sewage derived P had been exported from the observation area but, in spite of this, concentrations of labile f orms of P reaching 1900 mu g P g(-1) were amongst the highest reported for polluted estuarine sediments. The supply over 20 yr of high nutri ent loads would have been sufficient to produce 500 000 t of fixed car bon, of which 2% lies presently in the sediments of the surveyed area, (C) 1998 Elsevier Science Ltd. All rights reserved.