Historical PCDD Inputs and Their Source Implications from Dated Sediment Cores in Queensland (Australia)

Recent investigations have demonstrated the presence of an unidentified source of polychlorinated dibenzo-p-dioxins (PCDDs) in the coastal zone of Queensland (Australia). The present study provides new information on the possible PCDD sources and their temporal input to this environment. Two estuarine sediment cores were collected in northern Queensland for which radiochemical chronologies were established. Core sections from different depositional ages, up to three centuries, have been analyzed for 2,3,7,8-substituted PCDDs and polychlorinated dibenzofurans (PCDFs). Variations of PCDD concentrations in the sediment cores over several centuries of depositional history were relatively small, and elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F isomer patterns and congener profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. Profiles were dominated by higher chlorinated PCDDs, in particular octachlorodibenzodioxin (OCDD), whereas PCDF concentrations were below or near the limit of detection. These results indicate the presence of a PCDD source prior to industrialization and production of commercial organochlorine products. Further, the present study demonstrates that PCDD input patterns have been similar along an extensive but localized area over at least several centuries, contributing relatively high concentrations of PCDDs to the coastal system of Queensland.

Towards synthetic vaccines built on carbohydrate cores

Lipophilic polyfunctional carbohydrate core/templates have been designed and developed for drug/vaccine delivery. Three carbohydrate-based templates containing four protected N-terminal arms were synthesised from glucose and galactose. Methyl alpha-D-glucopyranoside was converted to two derivatives bearing a carboxylic acid handle for attachment to solid supports, spacer arms of differing hydrophilicity, and phthaloyl-protected amino groups suitable for peptide chain extension. beta-D-Galactopyranosyl azide was converted to a template bearing a carboxylic acid handle and four BOC-protected amines. All the templates were found to be suitable for attachment to solid supports and subsequent cleavage from resins, using either BOC- or FMOC-methodologies.