6.2 Procedure of Product Risk Assessment
109
6.2
Procedure of Product Risk Assessment
Similar to LCA, product risk assessment follows a set procedure with a few key steps
as outlined in the flowchart shown in Fig. 6.1. It can, however, also vary slightly in
the level of detail involved depending on whether the product is a new or existing
substance and whether an initial assessment limited to a set of specific protection
goals is needed or a more comprehensive assessment is required. Results from the
assessment can be the basis for reducing risks in the next iteration of the R&D cycle
and in production, insurance (product liability), marketing, or public relations. An
officially recognized risk assessment can also serve as the basis for complying with
legal regulations on the distribution and use of the product.
The principle of product risk assessment is classically based on a comparison
of the concentrations to which the protected good (humans or the environment) is
exposed and the concentration at which an adverse effect occurs.
As the first step of a product risk assessment, hazard identification aims to
determine the adverse effects that a substance is inherently able to cause. Subsequently, exposure assessment focuses on identifying the most critical emission
and dispersion scenarios during the use of a product and using them to calculate
the concentrations that humans and the environment are exposed to. An effect
assessment is also carried out to investigate the harmful effects the product can
cause, with the aim to determine the relationship between the dose and severity of
the adverse effects. The next step of risk characterization combines the results of the
exposure and effect assessments to characterize the specific risk the product poses
by comparing the predicted level of exposure with the threshold of a harmful effect.
The most common approach to describing this risk is the formation of a risk
quotient (RQ). For the example of environmental toxicity to an aquatic ecosystem,
the risk quotient can be simply defined as:
RQ aq.ecosystem =
Level of exposure for aquatic organisms
No-Effect level for aquatic organisms
=
PEC aq.
PNEC aq.
(6.1)
Here, PEC stands for “predicted environmental concentration” (from exposure
assessment) and PNEC means “predicted no-effect concentration” (from effect
assessment).
The risk quotient, however, is not an absolute measure of risk, but rather indicates
that the possibility of occurrence of adverse effects increases with an increasing
PEC/PNEC ratio. In this way, risks can be compared, but the actual risk cannot
be predicted. Despite this limitation, the risk quotient is by far the most widely
recognized risk assessment method internationally.
With the risk characterized, it can be evaluated in terms of data quality, protection
goals, risk-benefit ratio, societal acceptance, etc. in order to classify it as being
either acceptable or not acceptable. If not acceptable, the risk management step
then identifies risk reduction measures that need to be taken to ensure an acceptable
level of residual risk. Monitoring serves as an additional component within this step
109
6.2
Procedure of Product Risk Assessment
Similar to LCA, product risk assessment follows a set procedure with a few key steps
as outlined in the flowchart shown in Fig. 6.1. It can, however, also vary slightly in
the level of detail involved depending on whether the product is a new or existing
substance and whether an initial assessment limited to a set of specific protection
goals is needed or a more comprehensive assessment is required. Results from the
assessment can be the basis for reducing risks in the next iteration of the R&D cycle
and in production, insurance (product liability), marketing, or public relations. An
officially recognized risk assessment can also serve as the basis for complying with
legal regulations on the distribution and use of the product.
The principle of product risk assessment is classically based on a comparison
of the concentrations to which the protected good (humans or the environment) is
exposed and the concentration at which an adverse effect occurs.
As the first step of a product risk assessment, hazard identification aims to
determine the adverse effects that a substance is inherently able to cause. Subsequently, exposure assessment focuses on identifying the most critical emission
and dispersion scenarios during the use of a product and using them to calculate
the concentrations that humans and the environment are exposed to. An effect
assessment is also carried out to investigate the harmful effects the product can
cause, with the aim to determine the relationship between the dose and severity of
the adverse effects. The next step of risk characterization combines the results of the
exposure and effect assessments to characterize the specific risk the product poses
by comparing the predicted level of exposure with the threshold of a harmful effect.
The most common approach to describing this risk is the formation of a risk
quotient (RQ). For the example of environmental toxicity to an aquatic ecosystem,
the risk quotient can be simply defined as:
RQ aq.ecosystem =
Level of exposure for aquatic organisms
No-Effect level for aquatic organisms
=
PEC aq.
PNEC aq.
(6.1)
Here, PEC stands for “predicted environmental concentration” (from exposure
assessment) and PNEC means “predicted no-effect concentration” (from effect
assessment).
The risk quotient, however, is not an absolute measure of risk, but rather indicates
that the possibility of occurrence of adverse effects increases with an increasing
PEC/PNEC ratio. In this way, risks can be compared, but the actual risk cannot
be predicted. Despite this limitation, the risk quotient is by far the most widely
recognized risk assessment method internationally.
With the risk characterized, it can be evaluated in terms of data quality, protection
goals, risk-benefit ratio, societal acceptance, etc. in order to classify it as being
either acceptable or not acceptable. If not acceptable, the risk management step
then identifies risk reduction measures that need to be taken to ensure an acceptable
level of residual risk. Monitoring serves as an additional component within this step