Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:7:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 7 (pt 1/6)
Character Range: 2182876–2185842

7                   Copper

7.1              General
Several comprehensive reviews of copper in the environment and its toxicity to humans are available and should be consulted for more detailed information (ATSDR 2004; WHO 1998; NEHF 1997). The following provides a summary of the key aspects of copper that are relevant to the derivation of a soil HIL.

Copper (Cu) can occur naturally in its elemental form. Copper may also occur in the environment in various mineral forms including cuprite (Cu2O), malachite (CuCO3·Cu(OH)2), azurite (2CuCO3·Cu(OH)2), chalcopyrite (CuFeS2), chalcocite (Cu2S), and bornite (Cu5FeS4). Metallic copper is a malleable and ductile solid that has strong electrical and thermal conducting properties and low corrosiveness. Copper is a transition metal and may occur as either the monovalent or divalent cation. Copper may exist in four oxidation states Cu(0), Cu(I), Cu(II) and Cu(III) (ATSDR 2004; WHO 1998).

Copper is a naturally occurring trace element of significant societal importance. It is not only an essential nutrient in virtually all forms of life, it is also an important constituent in numerous consumer and industrial materials, both as the free metal and as a component in metal alloys. Common copper metal alloys include brass, bronze and gun metal. Copper and copper alloys are used in plumbing, telecommunications, power utilities, air conditioning, automotives, business electronics and industrial valves. Copper sulfate and other copper compounds are important constituents in products having agricultural (namely fungicides) and other applications, including metal finishing, wood preservatives and water treatment (ATSDR 2004).

Copper is an essential element and, as such, adverse effects may occur as a result of deficiency as well as excess intakes resulting from contamination.

7.2              Previous HIL
The derivation of the previous HIL (HIL A = 1000 mg/kg) for copper is presented by Soong & Emmett (1993) and as summarised in NEPC (1999). In summary, the HIL was derived on the basis of the following:
    * Intakes of copper from other sources were estimated with dietary intakes considered most significant for the general population. Background intakes for a 2-year-old child were estimated to be 1.1 mg/day (based on 95% intake from 1992 National Food Authority data) and 0.05 mg/day derived from drinking water.
    * A provisional tolerable daily intake (PTDI) of 170 µg/kg/week referenced from a study by Sloof et al. (1989) was adopted as the toxicity reference value.
    * Ingestion of both soil and dust has been considered assuming 100% is bioavailable and is absorbed.
    * The HIL was derived considering the above, as well as an additional safety factor of 10 to provide a margin of safety, as there is the likelihood of greater intakes of copper from drinking water in many households. The HIL derived was considered preliminary.

7.3              Significance of Exposure Pathways