•Petroleum and other materials are transformed by industrial processes into fuels,
plastic, pesticides, cosmetics, food additives and pharmaceuticals
•Residues of human made substance can now be found in the air, soil, water and
food web in the most remote reaches of the plant.
•Pollutants that are distributed ubiquitously result in universal human exposure
through inhalation, drinking water, and the food supply.
•Some of the substances to which the general human population is exposed resist
metabolism and excretion and therefore accumulate in body tissues.
•The quantity of an exogenous substance or its metabolites that has accumulated in
an individual or population is defined as a body burden.
•Individual’s body burden of a pollutant is estimated by measuring the
concentration of that substance in one or more tissues, usually by gas
•Chemical body burdens are complex and dynamic in a number of ways, and these
characteristics make a full characterization of the general public body burden
•First the body of burden of a pollutant is not stable over time. It reflects a
dynamic balance between the amount of taken in and the amount excreted or
metabolized into another material
•Second, body burdens are not distributed homogenously within an individual: the
partitioning of a pollutant among various tissues and fluids reflects the substances
degradability and affinity for fats, minerals and other endogenous materials.
•The choice of compartment in biomonitoring for any pollutants will affect the
level of measured, the limit of detection and the recency of exposure being
•Third, the body of burden of an individual in todays environment consist of
hundred of syntehic substances.
•Biomonitoring programs in the United States:
•Public health officials and scientists use biomonitoring information for
surveillance, control and treatment
•The purpose of many biomonitoring programs has been to assess the health risks
of occupationally or environmentally exposed individuals.
•Three biomonitoring surveys have studied broad samples of the U.S population.
•The NHATS programs has been criticized for lacking a standardized methodology
and using a sample of individuals that may not accurately reflect the nation
populations, but the programs results remain one of the most comprehensive
available data sets on the general populations body burden.
•A reference range is defined as the concentration of a particular substance that is
excepted to be present in the genral population with no unusal chemical exposure.
•The reference range is the standard against which a measuring laboratory can say
that results for any group or indivudal are high in a normal range or low.