Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p5
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 5/7)
Character Range: 2465845–2469052

2003 (same as previous ADI), based on a NOEL of 0.25 mg/kg/day from studies in humans and experimental animals, and an uncertainty factor of 100.
International
WHO (2011)          PTDI = 0.01 mg/kg/day     Provisional TDI referenced inWHO(2011) was established by JMPR in 2000 (as published by JMPR 2001) based on a NOAEL of 1 mg/kg/day for developmental toxicity in rats, and a safety factor of 100.
RIVM (2001)         TDI = 0.0005 mg/kg/day    TDI based on a NOAEL of 0.05 mg/kg/day associated with hepatotoxic effects in a 15 to 27-week study in female rats, and a 100-fold uncertainty factor.

ATSDR (2002)        No chronic value derived  Not derived as most sensitive non-cancer effects were observed at doses higher than doses for most sensitive acute and intermediate duration effects. The acute and intermediate MRL derived for DDT was 0.0005 mg/kg/day.
US EPA (IRIS 2012)  RfD = 0.0005 mg/kg/day    The US EPA review (last updated in 1987) derived an oral RfD on the basis of a NOEL of 0.05 mg/kg/day associated with liver effects in a rat study (1950 study), and uncertainty factor of 100. The US EPA has also derived an oral slope factor and inhalation unit risk, however these are not considered appropriate for the assessment of a non-genotoxic carcinogen.

There is a wide range of threshold values available for oral intakes of DDT. It is recommended that the oral value available from OCS (2012) ,which is consistent with the value in the ADWG (NHMRC 2011), be adopted for the derivation of an Australian HIL. The US EPA evaluation, while providing a more conservative TRV, has not been considered as it is significantly dated, using a key study from 1950. Reviews conducted by WHO and NHMRC are more current and have considered more recent studies.

No dermal or inhalation-specific studies or data are available. For the presence of DDT (DDE and DDD) in soil, it is considered appropriate to consider use of the available ADI for all pathways of exposures.

1.4.3         Recommendation
On the basis of the discussion above, the following toxicity reference values (TRVs) have been adopted for DDT, DDE and DDD (in total) in the derivation of HILs:

1.5              Calculated HILs
On the basis of the above, the following HILs have been derived for DDT+DDE+DDD (refer to Appendix B for equations used to calculate the HILs and Appendix C for calculations):
HIL Scenario            HIL (mg/kg)                      Percentage Contribution from Exposure Pathways
Ingestion of Soil/Dust  Ingestion of Home-grown Produce  Dermal Absorption of Soil/Dust                  Inhalation (dust)
Residential A           240                              80                                              --                 20  <1
Residential B           600                              51                                              --                 49  <1
Recreational C          400                              67                                              --                 33  <1
Commercial D            3600                             42                                              --                 58  <1

-- Pathway not included in derivation of HIL

1.6              References