Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 1/14)
Character Range: 2685009–2687841

1                   PCBs

1.1              General
Polychlorinated biphenyls (PCBs) are a group of synthetic organic compounds comprising two benzene rings joined together, with between one and ten chlorine atoms attached. There are 209 possible PCB variants (congeners) though PCBs are typically found as a complex mixture in commercial products and in the environment (WHO 1993). Of the 209 possible congeners, 12 are able to assume the same flat shape as dioxins and can cause impacts via the same mechanism. Consequently, it is normal to consider the PCB contribution to dioxin toxicity by measuring those congeners specifically. Some or all of these 12 congeners are always going to be present in any PCB contamination. There is evidence that using the dioxin‑like PCBs as the basis for assessing risk from PCBs is also protective for the risks from the non‑dioxin‑like PCBs, i.e. the non‑dioxin‑like PCBs are less toxic than the dioxin‑like PCBs.

The following relates to the assessment of non‑dioxin‑like PCBs only. The assessment of dioxins and dioxin‑like PCBs needs to be conducted on a site‑specific basis where there is the potential for a PCB source (such as PCB oil contamination) to be present at a site.

Several comprehensive reviews of PCBs in the environment and their toxicity to humans are available and should be consulted for more detailed information not presented in this summary (ATSDR 2000; WHO 1993; WHO 2003; EPHC 2003). The following provides a summary of the key aspects of PCBs that are relevant to the derivation of a soil HIL.

PCBs are typically in the form of an oily liquid or solid and are colourless to light yellow. Some PCB congeners may also exist as a vapour in air. They are odourless and tasteless. PCBs do not burn easily and have good insulating properties. They are both chemically and thermally stable. PCBs are relatively insoluble in water with the solubility decreasing with increasing chlorine content (ATSDR 2000).

Commercial PCB mixtures are also known by their trade names, such as Aroclor (USA), Phenochlor (France), Clophen (Germany), Kanechlor (Japan), Fechlor (Italy) and Sovol (USSR). Information on the toxicity and behaviour of a number of commercial PCB mixtures, Aroclors, is available, with Aroclor 1254 most commonly used as an indicator for the assessment of PCB mixtures. WHO (2003) provides a review of the most common commercial Aroclor mixtures with respect to the composition and toxicity of congeners present, and the various mixtures of indicator congeners (that differ from that of Aroclor 1254) may need to be considered on a site‑specific basis.

Due to the thermal and chemical stability of PCBs, they are widely used as coolants and lubricants in transformers, capacitors and other electrical equipment (ATSDR 2000). In Australia, PCBs were also used