Exposure Assessment by Multi-media modelling

1. Exposure Assessment by • Multi-media modelling

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

3. 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):

4. The eight compartment model of CalTOX

5. Compartments considered in the model: • air • plants • ground-surface soil • root-zone soil • vadose-zone soil • ground water • surface water • sediment

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

8. 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

9. 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

10. 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

11. 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.

12. 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.

13. 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.

14. Output data of CalTOX Predicted concentrations in: • breast milk • fish • milk • meat • eggs • tap water • swimming water

15. 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

16. 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

17. 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

18. 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

19. 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

20. Accumulation behaviour - Bioconcentration factor for fish - Cancer potency factor - Non-cancer ADI

21. 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

22. 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

23. Doses CalTOX • 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

24. Daily dermal uptake by humans from • surface soil • root-zone soil • ground water • surface water • total