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Exposure Pathways Research Paper

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The consequences of human exposure to the myriad of chemicals released into the environment may be impossible to predict, due to the sheer number of chemicals that humans may be exposed to, many pathways by which they can be exposed. Exposure and risk assessment have been developed to attempt to characterize the human health risks associated with exposure to chemicals.
Exposure pathways
Humans can be exposed to chemicals and physical agents through various exposure pathways. An exposure pathway describes the course that a substance takes from the source of chemical to be exposed individual. An exposure pathway generally consists of the following:
1. The source of the chemical
2. A medium (i.e. soil, water or air)
3. An exposure point, the …show more content…
Ingestion of mediums such as water, food and soil can result in the inadvertent consumption of toxic substances. Ingestion of contaminated drinking water , as well as ingestion of contaminated ground water and surface water can result in exposure to toxic chemicals. Ingestion of biota including fruits, vegetables, grains, meats and dairy, fish and shellfish, can all result in chemical exposure. Exposure to chemicals through the ingestion of contaminated soil occurs frequently. Soil particles can adhere to food and hands and subsequently come into contact with the mouth, with children more likely to ingest more soil than adults as a result of childhood behaviors (USEPA, …show more content…
Toxicity assessment consists of hazard identification and a dose-response evaluation.
Hazard identification is the determination of whether exposure to a chemical or physical agent can cause an increased incidence of a particular adverse health effect in humans, such as cancer and birth defects. Different types of studies are performed to collect these data, including epidemiological studies and clinical studies, but the bulk of our information comes from laboratory studies on animals.
The dose response evaluation determines the quantitative relationship between the level of exposure to a chemical and incidence of adverse health effects in the exposed population. Critical details such as the specific exposure route (inhalation or oral) as well as the length of exposure are noted. Key terms in the dose-response evaluation include the following:
Lowest-observed-adverse-effect-level (LOAEL)- The LOAEL is the exposure level at which the frequency or severity of adverse effects in an exposed population is statistically elevated compared to a control

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