Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:4:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 4 (pt 2/4)
Character Range: 2628164–2631139

exposures associated with dust have been considered in the HIL derived.

4.3.4         Plant Uptake
Most carboxylic herbicides are toxic to plants and, as such, will be phytotoxic to almost all broadleaf crops including tomatoes, grapes and fruit trees well before plant uptake into edible portions of fruit and vegetable crops is of significance. Hence the uptake of these compounds into home-grown produce has not been considered in the derivation of HIL A.

Note that the phytotoxic effects of these compounds may need to be addressed on a site-specific basis if detected in soil.

4.3.5         Intakes from Other Sources – Background
Limited data is available for the assessment of background intakes of picloram. Picloram products are currently registered for use in Australia and the compound is considered persistent in the environment. Picloram is not included in the Australian Total Diet Surveys (FSANZ 2003; FSANZ 2011) and there is no data regarding concentrations in drinking water or air in Australia. Away from areas where picloram products are used, exposure by the general public is expected to be low. Review by US EPA (1995b) suggests that dietary intakes comprise only 0.5% of the threshold reference value (RfD) adopted (0.2 mg/kg/day) for most of the US population, with intakes from non-nursing infants highest at 1.9% of the RfD adopted. Review by Health Canada (1988) also noted the maximum dietary intake of picloram is estimated to be negligible, based on available data in Canada and the USA. On this basis, intakes from other sources have been assumed to be negligible in the derivation of HILs.

4.4              Identification of Toxicity Reference Values

4.4.1         Classification
The International Agency for Research on Cancer (IARC 1991) has classified picloram as Group 3—not classifiable.

US EPA has not classified picloram.

4.4.2         Review of Available Values/Information
Studies associated with the assessment of carcinogenicity of picloram are noted to be affected by the presence of HCB as a contaminant/impurity. Hence a number of reviews of carcinogenicity are conflicting. The review by IARC noted limited evidence of carcinogenicity for technical grade picloram in experimental animals. In general, the available data suggests the picloram is not genotoxic (Health Canada 1988; US EPA 1995) or at most weakly mutagenic (OEHHA 1997). On the basis of the limited available information, it is considered appropriate that a threshold doseresponse approach be adopted for picloram. The following are available from Level 1 Australian and International sources:
Source                Value                    Basis/Comments
Australian
ADWG (NHMRC 2011)     TDI = 0.07 mg/kg/day     The current ADWG (NHMRC 2011) derive a guideline of 0.3 mg/L derived from a NOEL of 7 mg/kg/day associated with increased liver weights in a short-term dietary study in rats, and an uncertainty factor of 100.
OCS (2012)            ADI = 0.07