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.
Cadmium is found naturally in small quantities in air, water, and soil. Since cadmium is a metal, it does not break down and can accumulate over time. Burning household or industrial waste and burning coal or oil may release cadmium into the air.admium is released into the environment from mining and metal processing operations, burning fuels, making and using phosphate fertilizers, and disposing of metal products. People living near industry that conducts any of these activities may be exposed to cadmium.