Environmental Science Flashcards
Absorption (in biology)
penetration of a substance into an organism and its cells by various processes, some specialized, some involving expenditure of energy (active transport), some involving a carrier system, and other involving passive movement down an electrochemical gradient. In mammals absorption is usually through the respiratory tract, gastrointestinal tract, or skin into the circulatory system and from the circulation into organs, tissues, and cells
Acceptable risk
the risk that has minimal effects or for which benefits outweight the potential hazards. Calculated risk of an increase of one case in a million people per year for cancer is usually considered to be negligible
Acid deposition
acidification occurs after the release of nitrogen oxide and sulfur dioxide from point or nonpoint sources into the atmostphere. Chemical processes may transform these chemicals into sulfuric and nitric acids. These are returned to the earth in snowfallk rain, fog, and dust and may deposit at distances far from the original sources
acute exposure
a single exposure to a toxic substance which may result in sever biological harm or death. Acute exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing exposure over a period of time
additive effect
a biologic response to exposure to multiple substances that equals the sum of responses of all the individual substances added togerh
adverse health effect
a change in body function or cell structure that might lead to disease or health problems.
aerobic
life or process that require, or are not destroyed by, the presence of oxygen
aerosol
mixture of small droplets of particles (solid, liquid, or mixed) and a carrier gas (usually air)
Agency for Toxic Substances and DIsease Registry
The agency for Toxi c Substances and Disease Registry, based in Atlanta, is a federal public health agency of the U.S. HHS. ATSDR serves the public by using the best science, taking responsive public health actions, and providing trusted ehatlh information to prevent harmful exposures and diseases related to toxic substances
air toxics
any air pollutant for which a national ambient air quality standard (NAAQS) does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxide) that may reasonably be anticipated to cause cancer; respiratory, cardiovascular, or developmental effects; reproductive dysfunctions, neurological disorders, heritable gene mutations, or other serious or irreversible chronic or acute health effects in humans.
Alpha particl
a positively charged particle ejected spontaneously from the nuclei of some radioactive elements. It is identical to a helium nucleus that has a mass number of 4 and an electro static charge of +2. It has low penetrating power and a short range ( a few centimenters in air). THe most energetic alpha particle will generally fail to penetrate the dead layers of cells covering the skin and can be easily stopped by a sheet of paper. ALpha particles are hazardous when an alpha-emitting isotope is inside the body
ambient air
any unconfined portion of the atmosphere; open air, surrounding air
American Conference of Governmental Industrial Hygienists (ACGIH)
ACGIH is a member-based organization that advances occupational and environmental health. TLVs and BEIs
ANaerobic
a life or process that occurs in, or is not destroyed by, the absence of oxygen
analyte
a substance that is undergoing analysis or is being measured. For example, if the analyte is mercury, the lab test will determine the amount of mercury in the sample
antagonism (in toxicology)
combined effect of two or more factors that is smaller than the solitary effect of any one of those factors
anthropogenic
caused by or influenced by human activites
apoptosis
programmed cell death, the body’s normal method of disposing of damaged, unwanted, or unneeded cells
aqueous
of, relating to, or resembling water, made from, with, or by water