CONTRASTING PATTERNS OF SPATIAL AUTOCORRELATION OF PCDD/FS, DIOXIN-LIKE PCBS AND PBDES IN SEDIMENTS IN SYDNEY HARBOUR, AUSTRALIA

摘要

Sediments were collected from 25 sites, from five zones and across a 30 km transect of the Sydney Harbour / Parramatta River estuary. We analysed the concentrations of 34 PBDEs, 7 PCDDs, 10 PCDFs and 12 dioxin-like PCBs using HRGC/HRMS. For congeners above the LOD we used generalized additive modelling (GAM) to model their TOC normalized concentrations with respect to position in the estuary to examine how patterns of the spatial distribution and autocorrelation (Moran's I) varied among these contaminant groups. ∑PBDE, ∑PCDDs, ∑PCDFs, and PCBs concentrations spanned 1, 2, 1 and less than 1 orders of magnitude respectively, across the five sampling areas. The GAMs showed strongly contrasting spatial autocorrelation and distributions in the TOC normalised sediment concentrations both among and within PCDDs, PCDFs, dioxin-like PCBs and PBDEs. PCDD concentrations were associated with proximity to a source in Homebush Bay, whereas patterns of furan congeners were indicative either Homebush Bay sources or other sources. Dioxin-like PCBs concentrations were most highly variable indicative of more small scale sources. PBDEs also showed congener dependent spatial patterns but the main sources appeared to occur in the upper Parramatta River.