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Lecture

Normal body burdens.docx


Department
Renewable Resources
Course Code
REN R360
Professor
Melanie Muise

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Normal body burdens:
Hydrocarbon solvents are commonly found in fat and blood with toluene and xylene detected in
100 percent of NHANES III…
Body-burden variation:
Age:
Tissue concentration of industrial chemicals that bioaccumulation are expected to increase with
age.
Gender:
Sex differences in pollutant exposure and pharmacokinetics that may affect pollutant
accumulation have not been well studied.
Geography:
Although industrial chemicals are ubiquitous, location affects the magnitude of exposure.
Local pollutants source can cause increased exposures.
Surveys of pesticide exposure suggest that residents of rural agricultural communities have
higher body burdens than urban residents.
Race:
Blood-lead levels have been consistently found to be higher In African Americans than in whites.
Occupations:
There are ample data to confirm that persons will occupational exposures have higher body
burdens of industrial chemicals than person’s without such occupational exposures, chemical
and agricultural workers being the obvious examples.
Time trends:
Many studies confirm that concentrations of organochlorine chemicals that were restricted in
the United stats and Canada.
Critical populations: women and children:
Women, however excrete accumulated persistent chemicals into the fat of breast milk and in
small quantities.
One function of the placenta is to serve as a barrier to keep harmful substance from the embryo
and fetus, but fat soluble organocholins cross the placenta readily.
Public Health and Epideiological significance:
The measurement of body burden provides an assessment of an individuals long term exposure
to a chemical, a critical parameter in epidemiologiclogy and risk assessment
Bdoy burden measurements automatically account for differences between species in
metabolism and execration, increasing confidence in interspecies and interindivudal estimates
of toxicity.
The xenobiotic body burden is biologically important because it provides a reservoir for
continous internal exposure to these substances.
Measruments of body burdens also provides an important means to study the relation between
universal chemical exposure and adverse health outcomes.
Body burdens provide a present indicator of long term exposure, and analyses can target an
individual substance in the human population can be compared to those that produce adverse
health impacts in more easily studied lab animals.
Health effects as background exposures:
A study found that prenatal PCB exposure, determined as the burden of total PCBs in the
mothers plasma was related to lower birth weight, lower growth rate, lower psychomotor.
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