Environmental Engineering Reference
In-Depth Information
•
cluster investigations;
•
comprehensive case reviews;
•
situation-specific surveillance;
•
health statistics reviews;
•
exposure investigations;
•
disease and symptom prevalence surveys.
The quality of these studies depends on (ATSDR
1996
):
•
a reasonable ability to document and characterise exposure in the target area;
•
an adequate study size for the type of study recommended;
•
an ability to identify and locate subjects and records;
•
appropriate comparisons for rates of occurrence or levels of exposure; and
•
an ability to control confounding factors and biases (when possible).
More complex health studies are specifically designed to test scientific hypothe-
ses about the associations between adverse health outcomes and exposure to
contaminants in the environment. Examples are (ATSDR
1996
):
•
case-control studies;
•
cohort;
•
nested case-control.
The quality of these studies depends on (ATSDR
1996
):
•
an ability to reasonably estimate or document individual exposures;
•
an ability to document or validate human health outcomes;
•
an adequate study size and statistical power;
•
an ability to identify and locate subjects and records;
•
availability of an appropriate control or comparison population;
•
an ability to control confounding factors and minimise biases; and
•
an ability to determine influence of environmental, behavioural, or other factors.
12.5 Dose-Response Assessment
12.5.1 Introduction
The following section uses material from the NHMRC's Toxicity Assessment
Guidelines for Carcinogenic Soil Contaminants (
1999
) and Klaassen (
1996
).
There are different ways of characterising dose response relationships including
•
effect levels (e.g., LD
50
,LC
50
,ED
10
) and no observed adverse effect levels
(NOAELs);
•
margins of safety;
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