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Lecture

REN R360 Lecture Notes - Biomonitoring, Bioaccumulation, Carcinogen


Department
Renewable Resources
Course Code
REN R360
Professor
Melanie Muise

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Chemical Body Burdens:
o The quantitative amount of chemicals in our bodies that accumulates over times
o Most of the data is based on ANIMAL studies and can’t be done on humans because it is
unethical. Therefore, these data are somewhat comparable to humans but they are
great indicators of the direction of study.
o They are not stable over time. Their amount in the body changes over time because the
human body (special organs) may break down or rearrange the chemicals into other
chemicals. As well it is not distributed evenly throughout the body. For example, the
liver.
o There are some chemicals detected using detecting methods, but some are in so low
concentrations that they are not traceable.
o In Canada and the USA there is a program called biomonitoring which monitors the
common population to see how many chemicals are present in the average person and
if there are any health risks present.
Dioxins: gas when emitted but when then it becomes a chemical.
o Produced everywhere where there any form of combustion. Hamilton is significantly
contaminated with dioxins.
o No commercial usefulness/application. It is the by-product of combustion only. Even
during forest fires dioxins are produced.
o It is also produced during the manufacturing process.
o Dioxins are not just one chemical but a group of chemicals and have very similar
chemical structure. One of the most toxic and studied is 2, 3, 7, 8-tetrachlorodibenzo-p-
dioxin (TCDD).
o The more chlorine in a chemical, the more toxic it is in most general cases.
o Chlorination is the key process in how these chemicals become more toxic and what
affects their chemical properties in the environment. In addition, they affect the
solubility of chemical (e.g. more chlorine equals higher solubility in fats).
o These chemicals are very persistent and hard to remove: persistent organic pollutants
(POP).
o Dioxins are emitted in air but don’t remain there. Instead, they accumulate in food (e.g.
meat and milk products) and are consumed. Food is the major of contamination in our
bodies.
o All humans are exposed to low levels of dioxins and the effects of these levels are not
known however.
o Can cause cancer, heart problems, diabetes, immune deficiency
o One symptom that is evident that cause acne
DDT
o Subject of great concern
o It is used as agricultural pesticide
o It controls diseases such as malaria and typhus
o It breaks down to DDE and DDD
o Contributed greatly in the Green Revolution: more growth of agriculture
o Lasted for a couple of decades and was later realized it may affect the human health
o In the 1970s scientist discovered that it DDT harms the human health.
o The DDE and DDD are very dangerous to the human health compared to the parent
chemical DDT
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