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 (K OW ) Organic carbon-water partition coefficient (K OC ) 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 watersediment 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. 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

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