The influence of the association patterns of phosphorus-substrates and xylene-substrates on the degradation of xylenes in an alluvial aquifer

Abstract

The association patterns of xylene and of total phosphorus with sediment constituents in an alluvial aquifer consisting of clays and sands which had been contaminated by a spill of technical grade xylene were investigated with the aim of assessing the dependence of in situ xylene degradation on the P-availability. The investigated alluvial sediments of the Makis Plain (Sava river alluvion Quaternary age, Serbia and Montenegro) are relatively poor in P. The most reliable associations were proposed by analyzing the quality of the correlations of xylene- and of P-contents with 32 sediment characteristics. The association patterns depend on the mineralogical and granulometrical composition of sediments, the stuctural characteristics of the organic matter (N/C-ratio) and the redox-conditions. Differing association patterns in the clays and the sand had been developed, and these characteristics influence the intrinsic xylene degradation. The main proof for the occurence of xylene degradation is the percentul share of bacteria which oxidize xylene as a single carbon-source.

Ispitivani su glineni i peskoviti sedimenti Makiškog polja, zagađeni ksilenom (26-17800μg/kg), s ciljem da se utvrdi uticaj asocijacija ksilen-supstrat odnosno fosfor-supstrat na in situ degradaciju ksilena. Sedimenti Makiškog polja (aluvijalni sedimenti mlađeg Kvartara), imaju relativno nizak sadržaj fosfora. Analiziranjem korelacija ksilena i fosfora sa 32 sastojka sedimenata utvrđeno je da asocijacije ksilena i fosfora zavise od mineraloškog i granulometrijskog sastava sedimenta, strukturnih karakteristika organske supstance i redoks uslova sredine. Fosfor i ksilen u peskovitim i glinenim sedimentima grade različite tipove asocijacija, što se odražava i na degradaciju ksilena. Znatan udeo bakterija koje oksiduju ksilen kao jedini izvor ugljenika predstavlja pouzdan pokazatelj da se u sedimentima odvija degradacija ksilena.