(b) Toxicity assessment
Toxicity assessment aims to associate, in a qualitative and quantitative manner, the
concentrations of pollutants with the effects on receptors, based on the toxicological
and pathological evidence of pollutants in the study area. It specifically encompasses hazard determination and dose-response assessment.
• Analysis of health effects
The analysis of health effects of pollutants mainly covers the nature of negative
human health effects of pollutants (carcinogenic effects and/or non-carcinogenic
effects), as well as the toxicity mechanism and dose-response relationship of pollutants through different exposure pathways.
• Determination of toxicity values
As China has not yet established a comprehensive toxicity database for chemical
substances, data and information in the existing US database of this kind can be
used.
The data sources of such databases in the United States can divided into three
tiers. The first tier is IRIS values developed by the EPA; the second tier is the
Provisional Peer-Reviewed Toxicity Values (PPRTV) developed by the EPA’s
Office of Research and Development, National Center for Environmental
Assessment, and Superfund Health Risk Technical Support Center; and the third
tier is other toxicity values, including Minimum Risk Levels (MRLs) produced by
the Agency for Toxic Substances and Disease Registry, California Environmental
Protection Agency (CalEPA) values, and EPA Health Effects Assessment Summary
Tables (HEAST) values. When conducting a health risk assessment, the first tier is
applied, and where no IRIS values are available, the second and third tiers are used.
• Toxicity assessment of pollutants in the given landfill in Hubei Province
– Carcinogenicity identification
The carcinogenicity of focus pollutants is identified according to the findings of
IARC and IRIS. The IARC system for carcinogenicity classification is preferred,
followed by the US EPA system. The results of carcinogenicity identification are as
shown in Table 5.8. Four of the five focus pollutants are carcinogenic while the rest
is non-carcinogenic.
108
5 Application Cases
Toxicity assessment aims to associate, in a qualitative and quantitative manner, the
concentrations of pollutants with the effects on receptors, based on the toxicological
and pathological evidence of pollutants in the study area. It specifically encompasses hazard determination and dose-response assessment.
• Analysis of health effects
The analysis of health effects of pollutants mainly covers the nature of negative
human health effects of pollutants (carcinogenic effects and/or non-carcinogenic
effects), as well as the toxicity mechanism and dose-response relationship of pollutants through different exposure pathways.
• Determination of toxicity values
As China has not yet established a comprehensive toxicity database for chemical
substances, data and information in the existing US database of this kind can be
used.
The data sources of such databases in the United States can divided into three
tiers. The first tier is IRIS values developed by the EPA; the second tier is the
Provisional Peer-Reviewed Toxicity Values (PPRTV) developed by the EPA’s
Office of Research and Development, National Center for Environmental
Assessment, and Superfund Health Risk Technical Support Center; and the third
tier is other toxicity values, including Minimum Risk Levels (MRLs) produced by
the Agency for Toxic Substances and Disease Registry, California Environmental
Protection Agency (CalEPA) values, and EPA Health Effects Assessment Summary
Tables (HEAST) values. When conducting a health risk assessment, the first tier is
applied, and where no IRIS values are available, the second and third tiers are used.
• Toxicity assessment of pollutants in the given landfill in Hubei Province
– Carcinogenicity identification
The carcinogenicity of focus pollutants is identified according to the findings of
IARC and IRIS. The IARC system for carcinogenicity classification is preferred,
followed by the US EPA system. The results of carcinogenicity identification are as
shown in Table 5.8. Four of the five focus pollutants are carcinogenic while the rest
is non-carcinogenic.
108
5 Application Cases