Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 3/14)
Character Range: 2690152–2693736

by ATSDR (2000). Review of these studies suggests that, while the data is limited, the value recommended by US EPA (2004) is adequately representative.

1.3.3         Inhalation of Dust
PCBs are not considered sufficiently volatile to be of significance and inhalation exposures associated with particulates outdoors and indoors are expected to be of less significance than ingestion of soil. While likely to be negligible, potential inhalation exposures associated with dust have been considered in the HIL derived.

1.3.4         Plant Uptake
PCBs accumulate in terrestrial vegetation by the following possible mechanisms: uptake from soil through the roots; dry deposition on aerial parts (particle‑bound or gaseous); and wet deposition on aerial parts (particle‑bound or solute).Where PCBs are sorbed to soil and organic matter, the potential for plant uptake is reduced; however, it remains of potential significance (CCME 1999). The uptake of PCBs (in soil) into edible fruit and vegetable crops has been the subject of a number of studies with a range of bioaccumulation factors derived for different crops (ATSDR 2000), with adsorption onto root surfaces most significant compared with translocation within the root or upper portions of the plant (CCME 1999). On this basis, the potential for the uptake of PCBs into home‑grown produce has been considered in the derivation of an HIL A. This has been undertaken on the basis of the equations presented in Appendix B, with the following parameters and plant uptake factors estimated:
Parameter                                                                    Value              Reference/Comment
Parameters
Koc                                                                          131 000 (cm3/g)    RAIS (2010) for Aroclor 1254
log Kow                                                                      6.79               RAIS (2010) for Aroclor 1254
Diffusivity in water                                                         6.75x10‑6 (cm2/s)  RAIS (2010) for Aroclor 1221
Calculated Plant Uptake Factors (mg/kg produce fresh weight per mg/kg soil)
Green vegetables                                                             0.00026            calculated
Root vegetables                                                              0.0038             calculated
Tuber vegetables                                                             0.079              calculated
Tree fruit                                                                   0.00096            calculated

1.3.5         Intakes from Other Sources – Background
Background intakes (5.4 ng/kg/day for a child) were estimated by Di Marco & Buckett (1993) in the derivation of the previous HIL. Review of information available from FSANZ (2003) indicates that PCBs remain undetected in Australian and New Zealand food supplies, information consistent with that identified by Di Marco & Buckett (1993). Hence, intakes from food are considered negligible.

Intakes estimated by WHO (2003) are 0.33 ng/kg/day from air (including data derived from close‑to‑stack emissions from industrial/hazardous waste sources) and less than 0.2 ng/kg/day, from water. These values are similar to those noted above. Air concentrations reported by WHO (2003) from areas away from significant sources ranged from 0.0020.95 ng/m3 with PCBs in air noted to be slowly declining since the early 1980s. Based on these concentrations, intake of PCBs in air away from significant sources is approximately 0.3 ng/kg/day (the lower end of the range reported by WHO). Intakes