Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:11:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 11 (pt 4/9)
Character Range: 2274897–2277934

children (ATSDR 2005) range from 6.9 µg/kg/day (611 months old) to 9.5 µg/kg/day (children aged less than 18).
    * Typical concentrations of nickel reported in the ADWG (NHMRC 2011) are less than 0.01 mg/L, resulting in an intake (1 L/day and body weight of 15.5 kg) by toddlers of 0.6 µg/kg/day.
    * Based on intakes estimated from Australian data, background intakes by young children are approximately 7 µg/kg/day, up to 60% of the recommended oral TRV.
    * Nickel was reported in ambient air data collected in NSW (DEC 2003) where concentrations (24-hour averages) in urban, regional and industrial areas assessed ranged from 0.8620 ng/m3 (average of 3.5 ng/m3). Typical background concentrations in air reported in (EA (2009b) range from 0.34.5 ng/m3, consistent with that reported by DEC (2003). These background concentrations comprise (based on average concentrations) approximately 17% of the recommended TC. A conservative background of 20% of the recommended inhalation TRV has been assumed for intakes from air.

11.4          Identification of Toxicity Reference Values

    11.4.1     Classification
IARC (2012) classified nickel compounds a Group 1—carcinogenic to humans. The IARC working group noted that the overall evaluation of nickel compounds as a group was undertaken on the basis of the combined results of epidemiological studies, carcinogenicity studies in experimental animals, and several types of other relevant data supported by the underlying assumption that nickel compounds can generate nickel ions at critical sites in their target cells.

It is noted that US EPA has classified nickel refinery dust as Group A—human carcinogenic.

    11.4.2     Review of Available Values/Information
The toxicity of nickel is complex and appears to differ via the different routes of exposure and hence the following addresses oral exposures separately from inhalation exposures.

11.4.2.1     Oral
Review in WHO (2011) concluded that there was no substantial evidence that nickel compounds may produce cancers other than in the lung or nose in occupationally exposed persons. Limited animal studies on carcinogenic effects after oral exposures to nickel compounds did not show any significant increase in tumours. Review by EA (2009b) noted that while not all expert groups (WHO, US EPA, EU) have explicitly concluded that there is no carcinogenic concern from ingested nickel, none of those evaluating oral exposure concluded that a non-threshold approach should be undertaken. Hence the assessment of oral intakes on the basis of a threshold approach is reasonable. The following quantitative values are available from Level 1 Australian and International sources:
Source              Value                  Basis/Comments
Australian
ADWG (NHMRC 2011)   TDI = 0.005 mg/kg/day  The ADWG (NHMRC 2011) derived a health-based guideline of 0.02 mg/L based on NOEL of 5 mg/kg/day associated with organ-to-body-weight ratios in a 2-year rat study and an uncertainty factor of 1000. An additional factor of 10 was