When pollution is caused by nutrients and fertilizers, this is called nutrient pollution, and it leads to an overproduction of algae and other aquatic plants. This overabundance of plants and algae causes problems, because they cover the water surface and prevent sunlight from reaching the plants underwater.
Reverse T3 is actually an antithyroid -- T3 is the active thyroid that goes to the cells and stimulates energy and metabolism. Reverse T3 is a mirror image -- it actually goes to the receptors, sticks there, and nothing happens. So it blocks the thyroid effect. Reverse T3 is kind of a hibernation hormone, in times of stress and chronic illness, it lowers your metabolism.
A free T4 test may be used along with or following a TSH test and sometimes with a free T3 test to: 1  Help detect too much or too little thyroid hormone (hyperthyroidism and hypothyroidism) and diagnose the cause.2  Distinguish between different thyroid disorders. 3  Help diagnose pituitary disorders. free T4 test may be ordered when a person has symptoms of hyperthyroidism or hypothyroidism, particularly if the TSH test is out of range. Signs and symptoms of hyperthyroidism may include: 1  Increased heart rate.