What really is environmental toxicology and environmental health toxicology? Do you know guys what is toxicology? Today I will define the term of environmental toxicology and environmental health toxicology.
Environmental toxicology is defined as the study of the fate and effects of chemicals in the environment. It also can be divided into two subcategories which are environmental health toxicology and ecotoxicology.
Environmental health toxicology is the study of the adverse effects of environmental chemicals on human health. While ecotoxicology involves the study of the adverse effects of toxicants on myriad of organisms that compose ecosystems ranging from microorganisms to top predators.
TYPES OF TOXICANTS:
• Carcinogens: cause cancer (chemical in cigarettes)
• Mutagens: cause mutations in DNA
• Teratogens: cause birth defects (thalidomide)
• Allergens: cause unnecessary immune response
• Neurotoxins: damage nervous system (mercury and lead)
• Endocrine disruptors: interfere with hormones.
(source from http://amazingworldfactsnpics.com/health/shocking-ingredients-cigarettes/)
(source from http://logicallaw.tumblr.com/post/87958021501/corporations-cant-just-walk-away-from-10000)
It can divided into 2 broad categories:
(a) Toxic- Poisonous
It can be general or very specific and it often harmful even in dilute concentrations.
(b) Hazardous -Dangerous
It can be flammable, explosive, irritant, acid and very corrosive substance.
EXPOSURE AND SUSCEPTIBILITY
- Airborne toxins always cause more ill health than any other exposure because of the lining of lungs easily absorbs toxins.
-The largest toxin exposure reported in industrial or factories.
- The condition of organism and timing of exposure also have strong influences on toxicity
(source from http://experttoxicologist.com/toxicology-toxic-exposures.aspx)Movement, Distribution, and Fate of Toxins
-Solubility is the one of most important characteristics in determining the movement of a toxin.
The chemicals are divided into two major groups:
•Dissolve more readily in water.
•Dissolve more readily in oil.
The water soluble compounds move rapidly through the environment, and have ready access to most human cells.
Bioaccumulation and biomagnification
Bioaccumulation- accumulation of substances in an organism may be passed on to animals that eat the organism up the food chain.
(source from http://www.joshgitalis.com/bioaccumulation-what-you-must-know/)
Biomagnifications- is the increasing concentration of a substance, of a toxic chemical, in the tissues of organisms at successively higher levels in a food chain.
(source from http://www.slideshare.net/MrJewett/biomagnification-102)
Persistence
The quality of remaining for a long period of time. The persistent chemicals are not easily broken down.
There are 3 persistent Organic Pollutants (POP’s)
- Dichlorodiphenyltrichloroethane (DDT)
- Poly chlorinated biphenyl (PCD)
- Bisphenol A (BPA)
The rate of degradation is affected by:
(a) Temperature
(b) Moisture
(c) Sun exposure
Factors affecting toxicity
Sensitivity of a toxicant can vary with sex, age and weight. Babies, older people, or whom have in poor health are more sensitive or expose to toxicants.
4 type of exposure:
Acute –usually a single exposure for less than 24 hours, which is immediate got a health problem.
Sub-acute –exposure for one month or less.
Sub-chronic –exposure for one to three months.
Chronic –exposure for more than three months, it is very difficult to assess specific health effects due to other factors.
How to determine the dangerous of a chemical?
Type of Effects
i) Local effects –it damage at the site where a chemical first comes into contact with the body; examples are redness, burning and irritation of the skins.
ii)Systemic effects –it adverse the effects that associated with generalized distribution of the chemical throughout the body by bloodstream to internal organ.
iii) Target organ effects –some chemical may confine their effects to specific organ. The most common organs affected by such chemicals are liver, lungs, heart, kidneys, brain and nervous system, and the reproductive system.
References
All the points in this are not mine, please refer it from the book and the links that are listed at bottom below:
i) Robert H. Friss(2012). Essential of Environmental Health. Second Edition. Jones & Bartlett Learning
ii) Jay Withgottand April Lynch (2002). Environmental Health and Toxicology.
iii) Gerald A. Leblanca(2004). Basics of Environmental Toxicology. Textbook of Modern Toxicology, Third Edition, edited by Ernest Hodgson.
iv) Background Information for “Toxicity Testing with California Blackwormsand Alcohol”
v) Stefani D. Hines & Debbie Gevirtzman(2004). Introduction to Toxicology SWEHSC, University of Arizona
vi) https://en.wikipedia.org/wiki/Bioaccumulation
vii) https://en.wikipedia.org/wiki/Biomagnification
viii) https://www.health.ny.gov/environmental/glossary/
No comments:
Post a Comment