Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:14:p8
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 14 (pt 8/9)
Character Range: 2352514–2355910

250 mg/kg/day. Review of the available information in relation to cyanide does not indicate that the available science supports a change to the existing HIL, Hence the existing HIL A should be retained.
With respect to inhalation exposures to HCN, the value available from US EPA (2010) of 0.0008 mg/m3 has been adopted. It is noted that, similar to the derivation of an oral value, the approach adopted by US EPA is conservative (using large uncertainty factors) as the available data in relation to HCN exposures is more limited. Where HCN is expected to be of significance at a site, it should be evaluated on a site-specific basis as vapour intrusion issues may be of importance (not included in the derivation of HILs)).

    14.4.3     Recommendation
On the basis of the discussion above, the following toxicity reference values (TRVs) have been adopted for free cyanide in the derivation of HILs:

14.5          Calculated HILs
On the basis of the above, the following HILs have been derived for free cyanide (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           200*                             43                                              --                 57  <1
Residential B           300                              16                                              --                 84  <1
Recreational C          240                              27                                              --                 73  <1
Commercial D            1500                             12                                              --                 88  <1

* Retained existing HIL A of 250 mg/kg in guideline
-- Pathway not included in derivation of HIL

14.6          References

ATSDR 2006, Toxicological Profile for Cyanide, US Department of Health and Human Services, ATSDR, available from http://www.atsdr.cdc.gov/ToxProfiles/tp.asp?id=72&tid=19.
CCME 1997, Cyanide (Free), Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health, Canadian Council of Ministers of the Environment, Winnipeg.
DEFRA & EA 2002, Contaminants in Soil: Collation of Toxicological Data and Intake Values for Humans. Inorganic Cyanide, UK Department of Environment, Food and Rural Affairs and the Environment Agency, Bristol, UK.
DTSC 2005, Human Health Risk Assessment (HHRA) Note, California Department of Toxic Substances Control (DTSC), Human and Ecological Risk Division (HERD).
Jackson, LC, Chandler, JP & Jackson, RT 1986, 'Inhibition and adaptation of red cell glucose-6-phosphate dehydrogenase in vivo to chronic sublethal dietary cyanide in an animal model', Human Biology, vol. 58, pp. 67–77.
Jackson, LC 1988, 'Behavioural effects of chronic sublethal dietary cyanide in an animal model: implications for humans consuming cassava (Manihot esculenta)', Hum Biol , vol. 60(4), pp. 597–614.
Kamalu, BP 1993, 'Pathological changes in growing dogs fed on a balanced cassava (Manihot esculenta Crantz) diet', Br J Nutr, vol. 69(3, pp. 921–934.
Larsen, M 2005, 'Plant uptake of cyanide', PhD Thesis, Institute of Environment and Resources, Technical University of Denmark,