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.
Total T4 and free T4 are two separate tests that can help the veterinarian evaluate thyroid function. The total T4 test has been used for many years as a diagnostic test for humans, as well as dogs and cats. It is a very useful test and is the main test used to confirm suspected hyperthyroidism in cats.