Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:12:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 12 (pt 2/7)
Character Range: 2294827–2297710

be of less significance than ingestion of soil. While likely to be negligible, potential inhalation exposures associated with dust have been considered in the HIL derived.

    12.3.4     Plant Uptake
A detailed review of the plant uptake of selenium is presented by EA (2009b). This review considered studies that are based on the uptake of selenium into green vegetables, root vegetables, tuber vegetables and herbaceous fruit. No data was available on plant uptake into shrub fruit and tree fruit. The review provides recommendations on soil-to-plant uptake factors that are relevant for these types of produce. The recommendations from this review have been considered in the derivation of a residential A HIL and are summarised below for the range of crops considered:
Produce Group     Plant Uptake Factors (mg/kg produce fresh weight per mg/kg soil) (EA, 2009b)
Green vegetables  0.0108
Root vegetables   0.0036
Tuber vegetables  0.00083
Tree fruit        0.003

It is noted that the inclusion of home-grown produce in the calculations presented for HIL A results in some double counting of intakes from fruit and vegetable produce (also included in background intakes). To address this in the derivation of HIL A, half the intake estimated to be derived from home-grown produce is assumed to be already accounted for in the total background intake (noted below).

    12.3.5     Intakes from Other Sources – Background
Background intakes of selenium have been estimated by EA (2009a), where intakes from food dominated the total intake. Oral intakes by adults from background sources were estimated to be 34 µg/day from food and 1 µg/day from water. Inhalation intakes were estimated to be 0.06 µg/day based on an average ambient air concentration of 3 ng/m3.

Review of current information from Australia indicates the following:
    * Selenium in dietary intakes has been assessed most recently in the 20th, 22nd and 23rd Total Diet Surveys (FSANZ 2003, 2008 and 2011). The 22nd Total Diet Survey considered a wider range of food sources where estimated mean dietary intakes for children aged 23 were 2.8 µg/kg/day. Mean dietary exposures reported in the earlier 20th TDS were 2.63 µg/kg/day for toddlers aged 2 years.
    * Typical concentrations of selenium reported in the ADWG (NHMRC 2011) are less than 0.005 mg/L, resulting in an intake (1 L/day and body weight of 15.5 kg) by toddlers of 0.32 µg/kg/day.
    * Selenium 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 0.100.65 ng/m3 (average of 0.2 ng/m3). These concentrations are lower than those reported in EA (2009a). Based on the mean concentration reported in Australian air, intake by young children is approximately 0.15 ng/kg/day, significantly less than intakes from food and water.
    *