6.4 Exposure Assessment (Step 2)
115
Because a risk assessment is proactive in the case of a new chemical, the exposure
assessment cannot easily rely on direct measurements. Instead, exposures often have
to be estimated by models, and these generally require the following data about the
product:
• Amount placed on the market
• Emission potentials during application, use, and disposal
• Biologically available 1 exposure level, e.g., due to physical or chemical product
properties, such as particle size, water solubility, etc.
• Frequency and duration of exposure
• Specifically for human exposure:
– Exposure via air, soil, water, diet, as well as pharmaceutical and personal care
products
– Extent of exposed populations
6.4.1 Human Exposure
Figure 6.4 provides an overview of three categories of human exposure and
the different modeling approaches used to understand them. Local, short-term
exposures of humans are often caused by process accidents and are largely an
occupational safety issue. The dispersion models used to assess these are introduced
in more details in Chap. 7. Local, long-term exposures of humans often result from
the standard use of products and are a consumer health issue. These can often be
modeled with one-compartment models as described further below in this section.
Local, regional, and even global environmental exposures to a chemical are
modeled by means of multi-compartment environmental models, and these models
are presented in the next section on environmental exposure (Sect. 6.4.2). They
capture the situation in which humans are indirectly exposed to the chemicals that
circulate in the environment.
Human exposure is an important aspect to carefully consider during the development of a product and to also communicate along the supply chain. As shown
in Fig. 6.5, the number of people exposed to a chemical product increases over the
course of the product life cycle while at the same time the amount of knowledge
those exposed persons have regarding the safe handling of the product decreases.
6.4.1.1 Exposure Routes
Depending on a product’s use and properties, different human exposure routes (or
pathways) exist. The three primary routes of human exposure are oral, inhalation,
or dermal, and these are often quantified through calculating the predicted daily
intake (PDI) as shown in Eq. 6.2. Here, i indicates a contact medium (such as food,
1 Bioavailability: fraction of the total exposure that can readily be absorbed by the particular
organism considered and therefore readily interact with its biosystem
115
Because a risk assessment is proactive in the case of a new chemical, the exposure
assessment cannot easily rely on direct measurements. Instead, exposures often have
to be estimated by models, and these generally require the following data about the
product:
• Amount placed on the market
• Emission potentials during application, use, and disposal
• Biologically available 1 exposure level, e.g., due to physical or chemical product
properties, such as particle size, water solubility, etc.
• Frequency and duration of exposure
• Specifically for human exposure:
– Exposure via air, soil, water, diet, as well as pharmaceutical and personal care
products
– Extent of exposed populations
6.4.1 Human Exposure
Figure 6.4 provides an overview of three categories of human exposure and
the different modeling approaches used to understand them. Local, short-term
exposures of humans are often caused by process accidents and are largely an
occupational safety issue. The dispersion models used to assess these are introduced
in more details in Chap. 7. Local, long-term exposures of humans often result from
the standard use of products and are a consumer health issue. These can often be
modeled with one-compartment models as described further below in this section.
Local, regional, and even global environmental exposures to a chemical are
modeled by means of multi-compartment environmental models, and these models
are presented in the next section on environmental exposure (Sect. 6.4.2). They
capture the situation in which humans are indirectly exposed to the chemicals that
circulate in the environment.
Human exposure is an important aspect to carefully consider during the development of a product and to also communicate along the supply chain. As shown
in Fig. 6.5, the number of people exposed to a chemical product increases over the
course of the product life cycle while at the same time the amount of knowledge
those exposed persons have regarding the safe handling of the product decreases.
6.4.1.1 Exposure Routes
Depending on a product’s use and properties, different human exposure routes (or
pathways) exist. The three primary routes of human exposure are oral, inhalation,
or dermal, and these are often quantified through calculating the predicted daily
intake (PDI) as shown in Eq. 6.2. Here, i indicates a contact medium (such as food,
1 Bioavailability: fraction of the total exposure that can readily be absorbed by the particular
organism considered and therefore readily interact with its biosystem