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Exposure Assessment by Multi-media modelling. Cause-effect chain for ecosystem and human health as basis for exposure assessment by multi-media modelling (Fairman et al., 1998). CalTOX CalTOX is a multimedia, multiple pathway exposure, transport and transformation model.

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Exposure Assessment by Multi-media modelling

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  • Exposure Assessment by

  • Multi-media modelling


  • Cause-effect chain for ecosystem and human health as basis for exposure assessment by multi-media modelling (Fairman et al., 1998)


  • CalTOX

  • CalTOX is a multimedia, multiple pathway exposure, transport and transformation model.

  • Applications Limitations

  • Site-specific: local

  • Time scale : from one year to decades.

  • Substances assessable : non-ionic organic chemicals, radionuclides, fully dissociating in-/organic chemicals, solid-phase metal species, partially dissociated in-/organic species,

  • Available together with information and documentation via the Internet through page:

    (http://www.eetd.lbl.gov/ied/era ( version4.0):


The eight compartment model of CalTOX


Compartments considered in the model:

  • air

  • plants

  • ground-surface soil

  • root-zone soil

  • vadose-zone soil

  • ground water

  • surface water

  • sediment


The structure of the CalTOX model with the multimedia transport, the intermedia transfer and its exposure pathways


23 pathway human exposure scenario:

  • All inhalation exposures indoors active

  • All inhalation exposures indoors resting

  • Inhalation exposure in shower/bath

  • Inhalation exposures outdoors active

  • Inhalation of air particles indoors

  • Transfer of soil dust to indoor air

  • Transfer of soil vapors to indoor air

  • On-site inhalation by animals


Water

  • Use of ground water as tap water

  • Use of surface water as tap water

  • Ingestion of tap water

  • Use of ground water for irrigation

  • Use of surface water for irrigation

  • Use of ground water for feeding animals

  • Use of surface water for feeding animals


Plants

  • Contaminant transfer, air to plants surfaces

  • Contaminant transfer, ground soil to plant surfaces

  • Contaminant transfer, root soil to plant tissues

  • On-site grazing of animals

    Human Ingestion

  • Ingestion of home-grown exposed produce

  • Ingestion of home-grown unexposed produce

  • Ingestion of home-grown meat

  • Ingestion of home-grown milk

  • Ingestion of home-grown eggs

  • Ingestion of locally caught fish

  • Direct soil ingestion


Dermal

  • Soil contact exposure at home or at work

  • Dermal exposure during shower/bath

  • Dermal & ingestion exposures while swimming

    Infants

  • Breast-milk ingestion by infants.


  • Input data of CalTOX

  • Data describing the substance

  • Physico-chemical properties

  • Measured emissions into the compartments

  • Background concentrations of the contaminant

  • Toxicological properties, consisting of a cancer and a non-cancer potency for human beings, since only human risk is considered in CalTOX.


Data characterising the area:

  • Geographical data like the contaminated area size

  • Meteorological and hydrological data, e.g. the average depth of surface water, the annual average precipitation, wind speed or environmental temperature

  • Soil properties, like the organic carbon fractions

  • Data about the human population, e.g. the average body weight or daily intake rates for different kinds of food.


  • Output data of CalTOX

    Predicted concentrations in:

  • breast milk

  • fish

  • milk

  • meat

  • eggs

  • tap water

  • swimming water


Estimated exposure media concentrations

  • indoor air

  • outdoor air

  • bathroom air

  • tap water

  • swimming water

  • un-/exposed produce

  • meat

  • milk

  • eggs

  • fish and seafood

  • household soil


  • Some properties like fugacity capacities or boundary layer thickness in different media are also calculated.

    Daily human doses by:

  • inhalation,

  • ingestion (breast milk, water, milk, meat, fish, soil)

  • dermal uptake


Final results:

  • Individual human lifetime Risk for developing cancer

    Risk = chronic daily intake * slope factor

  • Hazard ratio for non-carcinogenic effects attributable to exposure over a certain period which can be defined by the user.

    Hazard ratio = intake/reference dose


  • Inputs used in CalTOX

  • Physico-chemical properties

  • Molecular weight

  • Melting point

  • Vapour pressure

  • Water solubility

  • Henry's law constant

  • Octanol-water partition coefficient (KOW)

  • Organic carbon-water partition coefficient (KOC)

  • Degradation rates

  • Half-life time in air

  • Half-life time in water

  • Half-life time in sediment

  • Half-life time in soil

  • Emission to regional air

  • Emission to regional surface water

  • Regional emissions to soil


  • Time

    - Averaging time

    - Exposure duration

    Area description

    - Area

    - Average wind speed

    - Average annual precipitation

    - Average environmental temperature

    Humans description

    - Egg intake

    - Grain intake

    - Fruit and vegetable intake

    - Milk intake

    - Fish intake

    - Meat intake

    - Body weight


    Accumulation behaviour

    - Bioconcentration factor for fish

    - Cancer potency factor

    - Non-cancer ADI


    Predicted concentrations in environmental media:

    airair (gases)

    air (particles)

    (annual) average in air (total)

    soilground soil

    root zone soil

    vadose zone soil

    off-site surface soil

    ground water

    surface water

    annual average in surface water

    sedimentsediment

    aquifer


    • Predicted concentrations in exposure mediaCalTOX

      • plants/grass

      • fish/seafood

      • meat

      • milk

      • drinking water

      • eggs

      • breast milk

      • swimming water

      • indoor air

      • bathroom air

      • outdoor air

      • household soil


    • DosesCalTOX

    • Daily human doses through intake of

      • drinking water

      • air

      • fish

      • meat

      • milk

      • total

      • eggs

      • soil

      • breast milk (infants)

    • daily inhalation by humans of

      • surface soil

      • root-zone soil

      • ground water

      • surface water

      • total


    • Daily dermal uptake by humans from

      • surface soil

      • root-zone soil

      • ground water

      • surface water

      • total


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