Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 1/6)
Character Range: 2401209–2404114

2                   Phenol

2.1              General
Several comprehensive reviews of phenol in the environment and its toxicity to humans are available and should be consulted for more detailed information not presented in this summary (ATSDR 2008; WHO 1994; Health Canada, 2000; UK EA 2009). The following provides a summary of the key aspects of phenol that is relevant to the derivation of a soil HIL.

Phenol is a colourless to white to pale pink crystalline solid at room temperature and ambient pressure. Phenol has a distinctive aromatic, somewhat 'sickening', sweet and acrid odour. Phenol is soluble in water and miscible with most organic solvents (e.g. acetone and benzene) (ATSDR 2008). Many substituted phenols exist, for example dimethyl and trimethylphenols. These have different toxicities from phenol (ATSDR 2008). The widely varying toxicities and difficulty of making a generic assumption on the likely composition of phenol mixtures mean presenting an HIL representing 'total phenols' is considered impractical.

Therefore if substituted phenols may be present, these should be analysed and assessed as separate compounds, rather than on the basis of the phenol HIL.

Phenol can occur naturally in the environment as a product of organic matter decomposition and combustion of wood. Phenol is manufactured for use in phenolic resins, disinfectant and antiseptic and as an intermediate in organic synthesis (ATSDR 2008). Anthropogenic sources of phenol in the environment include vehicle exhaust and waste streams associated with its manufacture. Predominantly, phenol is released as an air emission resulting from venting. Phenol can also be released in the metabolic processes in which it occurs as an intermediate. For example, phenol can be produced from the degradation of organic wastes containing benzene, an organic compound found extensively in the environment. Its primary occurrence as a soil contaminant is in former gas works and coking works sites (ATSDR 2008).

2.2              Previous HIL
The derivation of the previous HIL (HIL A = 8500 mg/kg) for phenol is presented by Turczynowicz (1993) and NEPC (1999). In summary, the HIL was derived on the basis of the following:
    * Background intakes were considered in the derivation of the previous HIL with the intakes from food, water and ambient air considered, where available. Due to the lack of available data, the quantification of intakes was limited, hence intakes from contaminated soil were taken to be 25% of the adopted ADI to address these limitations.
    * An RfD of 0.6 mg/kg/day referenced from US EPA, based on a NOAEL of 60 mg/kg/day and uncertainty factor of 100 was considered.
    * Dermal absorption of phenol was considered to be 12%.
    * Oral bioavailability of phenol was considered to be 100%.
Based on intakes derived from soil (ingestion, dermal absorption and dust inhalation) an HIL of