Using SPMDs to monitor water column concentrations of PCDDs, PCDFs and dioxin-like PCBs in Port Jackson (Sydney Harbour), Australia

Semipermeable membrane devices (SPMDs) were deployed on two occasions throughout Sydney Harbour, Australia, along a 25 km transect. They were used to measure spatial and temporal variation in the available concentrations of 7 polychlorinated dibenzo- p-dioxins (PCDDs) and 10 polychlorinated dibenzofurans (PCDFs) and 12 dioxin-like polychlorinated biphenyls (PCBs) in the water column. The relative percent difference (%RPD) among spatially replicated cages (within 0.13–0.41 km) ranged from less than 8% to greater than 66% across all congeners and was greater for WHO 05-TEQ DFP (average = 36%), PCDFs (average = 34%) and PCDDs (average = 33%) than PCBs (average = 23%). Total PCDD (∑PCDDs) concentrations ranged between 2.7 and 84 pg L −1, ∑PCDF concentrations ranged from 0.15 to 7.2 pg L −1, ∑PCB concentrations ranged between 21 and 540 pg L −1 and WHO 05-TEQ DFP ranged from 0.069 to 1.85 pg L −1. Highest concentrations were measured in SPMDs deployed in Homebush Bay and concentrations generally declined with distance from Homebush Bay. SPMDs detected changes in congener profiles downstream with OCDD, 2,3,7,8-TCDF and PCBs 189, 157, 167, and 126 increasing in proportion with distance from Homebush Bay. There was a large increase in the daily accumulation of the analytes from winter to summer resulting in an average 3.9-fold increase in the predicted concentration at one site with matched SPMDs.