ANTIBIOTIC SUSCEPTIBILITY TESTING. Bacteria demonstrate two kinds of resistance to antibiotics, namely intrinsic resistance and acquired resistance. Intrinsic resistance means that the species was resistant to an antibiotic even before its introduction.
Radiation is naturally present in our environment, as it has been since before the birth of this planet. In addition, radiation can be produced artificially, as in medical x-rays and microwaves for cooking. Nonetheless, most people are not aware of all the natural and man-made sources of radiation in our environment.
The actual risk depends on several factors: 1  The specific radioactive materials, or isotopes, released, and the quantities released. 2  How a person comes into contact with the released radioactive materials (such as through contaminated food, water, air, or on the skin).n the most severe kinds of accidents, such as the Chernobyl accident in 1986, other dangerous radioactive isotopes, such as strontium-90 (Sr-90) and plutonium-239, may also be released. Human exposure to I-131 released from nuclear power plant accidents comes mainly from consuming contaminated water, milk, or foods.