Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 3/6)
Character Range: 2477933–2480858

be insignificant. Hence, the potential for plant uptake of aldrin and dieldrin from soil contamination is considered negligible.

It is noted, however that should these compounds be present in other media such as groundwater (used for irrigation) or solution, then the potential for uptake into fruit and vegetable crops is likely to be of significance. In addition, the mobility of these compounds in the soil environment can be enhanced by the presence of organic solvents. These organic solvents have the ability to increase the water solubility of non-polar compounds, which in turn increases their mobility in soil. The organic solvents in a sense act as a transport medium for chemicals that would normally bind strongly to soil (ATSDR 2002). These issues should be assessed on a site-specific basis.

2.3.5         Intakes from Other Sources – Background
For the general population where aldrin and dieldrin are no longer used, background intakes would be expected to be primarily associated with residues in food. Food Standards Australia and New Zealand has not detected aldrin or dieldrin in any sample in the 19th or 20th food surveys (FSANZ 2003). Dieldrin was reported (at 1.283.23% of the ADI adopted) in the earlier 18th survey and again in the most recent survey (FSANZ 2011) with the highest intake estimated to be 0.021 µg/kg/day for children aged 25 years, which comprises 20% of the adopted oral TRV. Other than the most recent food survey, intakes of aldrin and dieldrin are negligible, however the higher level of intake estimated for young children more recently suggests intakes are not negligible. For the purpose of establishing a soil HIL, an intake of 10% (assumed to represent a longer-term average of intakes from the available food surveys) of the TRV from other sources has been assumed.

2.4              Identification of Toxicity Reference Values

2.4.1         Classification
The International Agency for Research on Cancer (IARC) has classified aldrin and dieldrin as Group 3—not classifiable as to carcinogenicity to humans. It is noted that US EPA has classified both aldrin and dieldrin as Class B2—probable human carcinogens.

2.4.2         Review of Available Values/Information
There are mixed reviews of carcinogenicity with respect to aldrin and dieldrin. Based on a review by RIVM (2001) it is noted that epidemiological data remains inadequate, though some studies have shown hepatocellular carcinomas in mice, while other studies have not shown carcinogenic effects. Further evaluation of carcinogenicity by Stevenson et al. (1999) within the framework of the US EPA Proposed Guidelines for Carcinogen Risk Assessment considered that dieldrin-induced liver tumours occur through a non-genotoxic mode of action. The review also considers that a more appropriate cancer descriptor for aldrin/dieldrin is 'not likely to be carcinogenic to humans'.

On the basis of the available