Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p113
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 113/117)
Character Range: 687480–690795

around Australia were collected and analysed for dioxins. Dioxin-like chemicals were found in all but one of the 114 Australian soils sampled, with concentrations ranging from the limit of detection (0.05 pg TEQ g-1 dwt) to 43 pg TEQ g-1 dwt. Note the results of the study are reported based on WHO98 TEQs.

The greatest concentrations of dioxin-like chemicals were found in soils collected near centres of population within the south-east coastal area of Australia, whereas concentrations were consistently low in soils collected from locations in Western Australia and inland areas. Data from the study showed that levels of dioxin-like chemicals in soils from urban and industrial locations were substantially higher relative to agricultural land use and remote locations. This pattern was consistent regardless of whether levels were expressed as toxic equivalents or as concentrations.

Homologue and congener profiles for the PCDD/Fs were strongly dominated by octachlorodibenzo-p-dioxin (OCDD). Similarly, the tetra-heptachlorinated 2,3,7,8-chlorine substituted profiles are dominated by the highest chlorinated PCDD, 1,2,3,4,6,7,8-heptachloro dibenzodioxin. The source or formation processes by which dominance of higher chlorinated congeners could occur remains unresolved despite intensive studies. With regards to the TEQs, on average, more than 80% of the toxic equivalency across soil samples was attributed to 2,3,7,8-PCDD/Fs.

There is no Australian guideline threshold for dioxin-like chemicals in soils. Comparison of concentrations of dioxin-like chemicals in the NDP soil samples against a categorisation derived from German thresholds showed that only 15% of the Australian samples (all but one of which were from urban or industrial locations) exceeded the German derived target value of < 5 pg TEQ g-1 dwt and only one sample exceeded the guideline threshold of acceptability for specific agricultural uses of soil. Australian jurisdictions do not have a generic action or response level for dioxin-like compounds, but may adopt a site-specific investigation and/or response level for dioxins following a site-specific risk assessment.

The concentrations of dioxin-like chemicals in urban and industrial locations sampled as part of the NDP were similar to those reported in previous Australian studies and in the New Zealand Organochlorine Program. On the basis of toxic equivalents, concentrations of dioxin-like chemicals are on average much lower than those reported from many industrial sites internationally and, globally, can be considered among the lowest background concentrations reported in soil from any industrialised nation.

    22              Shortened forms
AHD         Australian Height Datum
APHA        American Public Health Association
ASS         acid sulfate soil
Bonded ACM  bonded asbestos-containing materials
BTEX        benzene, toluene, ethylbenzene, and xylenes
CPT         cone penetrometer testing
CRM         Certified reference material
CSM         conceptual site model
DNAPL       dense non-aqueous-phase  liquid
DO          dissolved oxygen
DQI         data quality indicator
DQO         data quality objectives
DSI         detailed site investigation
EC          electrical conductivity
ECD         electron capture detector
Eh          Redox potential