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close this bookConducting Environmental Impact Assessment in Developing Countries (United Nations University, 1999, 375 p.)
close this folder9. Emerging developments in EIA
close this folder9.5 Environmental health impact assessment
close this folder9.5.2 Potential methodologies and approaches for addressing health impacts
View the document(introduction...)
View the document9.5.2.1 Adapt EIA study activities
View the document9.5.2.2 Integrate health impacts into EIA
View the document9.5.2.3 Use a targeted approach
View the document9.5.2.4 Probabilistic risk assessment Integrate health impacts into EIA

Integrate an existing health impact methodology into the typical activities in an EIA study or use the health impact methodology as the focus of the EIA study. To serve as an example, a generic methodology for EHIA has been suggested by the WHO. It consists of the nine steps listed in Table 9.11. Steps 1 and 2 are related to the normal EIA process in which primary, secondary, and tertiary impacts on environmental parameters are assessed. Step 3 is derived from information given in the EIA and for which environmental health factors can be identified. Methods for identification of environmental health factors could be based on epidemiological and/or toxicological evidences of causal links between environmental parameters and health effects. Step 4 involves the study of exposure pathways. Steps 5 and 6 use epidemiological and toxicological information on dose-incidence and dose-response relationships between environmental parameters and specific health effects. Step 7 can be used to evaluate significance and acceptability of adverse health effects, and step 8 focuses on mitigation measures. Finally, step 9 involves appropriate decision-making. This generic EHIA methodology has been modified to allow its use for chemical manufacturing facilities.

Table 9.11 Steps in EHIA methodology

Item number

Steps to be taken

Tools to be used

Step 1

Assessments of primary impacts on environmental parameters

Regular impact assessments process

Step 2

Assessments of secondary and tertiary impacts on environmental parameters

Regular impact assessments process

Step 3

Screening of impacted environmental parameters of recognized health significance (EH factors)

Epidemiological knowledge

Step 4

Assessments of the magnitude of exposed population for each group of EH factors

Census, land use planning

Step 5

Assessments of the magnitude of risk groups included in each group of exposed population


Step 6

Computation of predicted health impacts in terms of mortality and morbidity, if possible

Results from risk assessments studies

Step 7

Definition of acceptable risk (or of significance of adverse health impacts)

Assessments of trade off between human and economic requirements

Step 8

Identification of mitigation measures to prevent or reduce significant adverse health impacts

Abatement of EH factors? Magnitude reduction of exposure, reduction of exposed populations, protection of risk groups

Step 9

Final decision on whether or not the project should proceed

Source: Giroult, 1988, WHO Interest in EHIA, In: Wathern, P. (Ed.) Theory and Practice, Routledge: London.