Abstract

Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentrations were measured in sediment and seagrass from five locations in or adjacent to the Great Barrier Reef Marine Park. A full spectrum of Cl(5-8)DDs were present in all samples and, in particular, elevated levels of Cl8DD were found. PCDFs could not be quantified in any samples. The PCDD concentrations ranged over two orders of magnitude between sites, and there was a good correlation between sediment and seagrass levels. There were large quantities of sediment present on the seagrass (20-62% on a dry wt. basis), and it was concluded that this was a primary source of the PCDDs in the seagrass samples. The PCDD levels in the seagrass samples were compared with the levels in the tissue of three dugongs stranded in the same region. The relative accumulation of the 2,3,7,8-substituted PCDD congeners in the dugongs decreased by over two orders of magnitude with increasing degree of chlorination. This was attributed to the reduced absorption of the higher chlorinated congeners in the digestive tract, a behaviour that has been observed in other mammals such as domestic cows. (C) 2001 Elsevier Science Ltd. All rights reserved.

Author Keywords: Great Barrier Reef, dugong, PCDD/Fs, bioaccumulation, food chain, marine mammals

KeyWords Plus: DIBENZO-P-DIOXINS, SEWAGE-SLUDGE, QUEENSLAND

Addresses:
McLachlan MS, Baltic Sea Res Inst, Postfach 301161, D-18112 Rostock, Germany Univ Bayreuth, D-95440 Bayreuth, Germany Great Barrier Reef Marine Pk Author, Townsville, Qld 4810, Australia Univ Queensland, Natl Res Ctr Environm Toxicol, Coopers Plains, Qld 4108, Australia

Publisher: ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND

IDS Number: 433GF

ISSN: 0269-7491