• Technical Evaluation of the Intervention Values for Soil/Sediment and
Groundwater issued by the Netherlands National Institute for Public Health and
the Environment (RIVM);
• IARC;
• Toxicity Factors and Chemical/Physical Parameters of the Texas Risk
Reduction Program.
4.1.1.2 Dose–Response Assessment
Dose–response assessment analyzes the adverse human health effects of focus
pollutants based on hazard identification, including carcinogenic and
non-carcinogenic effects, and further determines parameters related to focus pollutants, including reference dose, reference concentration, cancer slope factor, and
inhalation unit risk.
In the case of chemical substances, the dose–response relationship is estimated
on the basis of investigations and experimental data. Therefore, the epidemiological
data of humans is preferred, while the long-term carcinogenicity data of sensitive
animals are of extreme importance. For threshold compounds, the no observed
adverse effect level (NOAEL) is often used as the reference level for risk assessment of genotoxic-free substances, and expressed by acceptable daily intake
(ADI) which refers to the maximum amount of chemical substances ingested daily
by humans without causing any visible damage. Since the experiment parameters in
toxicology database are not designed for ADI identification, it is difficult to find
results with appropriate observation endpoints and appropriate exposure time in
existing database for dose–response assessment. In this case, new experiments are
needed to quantify ADI values, or the actual intake and the temporarily established
ADI values are considered to determine whether new experiments are needed. For
non-threshold compounds, the traditional extrapolation model in toxicology is
adopted to extrapolate human dose–response relationship from animal experimental
data, usually by weight, body surface area or safety factor. Where the extrapolation
is beyond the range of experimental dose, the predicted value and the response
value can differ by several orders of magnitude. Therefore, the model should be
carefully selected according to the characteristics of non-threshold compounds and
the relevant data collected.
However, regardless of thresholds or methods, the dose–response relationship is
estimated by models based on epidemiological investigations and experimental
data. The IRIS toxicity database contains toxicology data about carcinogenic and
non-carcinogenic effects of more than 540 chemical substances. The toxicity criteria
database built by California Office of Environmental Health Hazard Assessment
(OEHHA) contains information on the toxicity of more than 400 chemical substances. China still lags behind in such basic data collection and toxicology database establishment.
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4 Risk Assessment of Groundwater Contamination Sites
Groundwater issued by the Netherlands National Institute for Public Health and
the Environment (RIVM);
• IARC;
• Toxicity Factors and Chemical/Physical Parameters of the Texas Risk
Reduction Program.
4.1.1.2 Dose–Response Assessment
Dose–response assessment analyzes the adverse human health effects of focus
pollutants based on hazard identification, including carcinogenic and
non-carcinogenic effects, and further determines parameters related to focus pollutants, including reference dose, reference concentration, cancer slope factor, and
inhalation unit risk.
In the case of chemical substances, the dose–response relationship is estimated
on the basis of investigations and experimental data. Therefore, the epidemiological
data of humans is preferred, while the long-term carcinogenicity data of sensitive
animals are of extreme importance. For threshold compounds, the no observed
adverse effect level (NOAEL) is often used as the reference level for risk assessment of genotoxic-free substances, and expressed by acceptable daily intake
(ADI) which refers to the maximum amount of chemical substances ingested daily
by humans without causing any visible damage. Since the experiment parameters in
toxicology database are not designed for ADI identification, it is difficult to find
results with appropriate observation endpoints and appropriate exposure time in
existing database for dose–response assessment. In this case, new experiments are
needed to quantify ADI values, or the actual intake and the temporarily established
ADI values are considered to determine whether new experiments are needed. For
non-threshold compounds, the traditional extrapolation model in toxicology is
adopted to extrapolate human dose–response relationship from animal experimental
data, usually by weight, body surface area or safety factor. Where the extrapolation
is beyond the range of experimental dose, the predicted value and the response
value can differ by several orders of magnitude. Therefore, the model should be
carefully selected according to the characteristics of non-threshold compounds and
the relevant data collected.
However, regardless of thresholds or methods, the dose–response relationship is
estimated by models based on epidemiological investigations and experimental
data. The IRIS toxicity database contains toxicology data about carcinogenic and
non-carcinogenic effects of more than 540 chemical substances. The toxicity criteria
database built by California Office of Environmental Health Hazard Assessment
(OEHHA) contains information on the toxicity of more than 400 chemical substances. China still lags behind in such basic data collection and toxicology database establishment.
70
4 Risk Assessment of Groundwater Contamination Sites