A chemical used as the primary ingredient of solid rocket propellant and in munitions beginning in the 1950s. Perchlorate is also used in the production of explosives and fireworks. It adds the blue color to firework displays. Perchlorate remains in use and is unregulated. For disposal, perchlorate has often been dissolved in water and poured on the ground. Perchlorate dissolves easily and moves quickly in underground water and surface water. It breaks down very slowly in the environment. Wastes from the manufacture and improper disposal of perchlorate-containing chemicals are increasingly being discovered in soil and water. Traces of perchlorate have been found in groundwater in virtually every state in the US. It has been detected in many rivers and low levels have been found in some lettuce samples and milk. The term perchlorate includes ammonium perchlorate, potassium perchlorate, sodium perchlorate, and perchloric acid.
Perchlorate interferes with iodide uptake into the thyroid gland. Because iodide is an essential component of thyroid hormones, perchlorate disrupts the function of the thyroid. The thyroid helps to regulate metabolism. In children, the thyroid also plays a major role in proper development. Impairment of thyroid function in expectant mothers may impact the fetus and newborn and result in effects including changes in behavior, delayed development and decreased learning capability. Changes in thyroid hormone levels may also result in thyroid gland tumors.
There are several types of treatment systems designed to reduce perchlorate concentrations. Biological treatment and ion (anion) exchange systems are among the technologies in use. In the US there has been disagreement between different parts of the government — between the Defense Department and NASA on the one hand and the Environmental Protection Agency (EPA) on the other — about the danger of perchlorate and the need to clean it up.
Through the skin. For example, a percutaneous biopsy is a biopsy that is obtained by putting a needle through the skin in order to obtain tissue within the body for examination.
- Percutaneous endoscopic gastrostomy (PEG)
A surgical procedure for placing a feeding tube without having to perform an open laparotomy (operation on the abdomen). The aim of PEG is to feed those who cannot swallow. PEG may be done by a surgeon, gastroenterologist (GI specialist). It is done in a. hospital or outpatient surgical facility. The patient is usually mildly […]
- Percutaneous endoscopic jejunostomy
(PEJ) A surgical procedure for placing a feeding tube into the jejunum (part of the small intestine) without having to perform an open laparotomy (an operation opening the abdomen). The aim of PEJ is to feed a patient who cannot swallow. PEJ may be done by a surgeon or gastroenterologist (GI specialist).
- Percutaneous nephrolithotripsy (PNL)
A technique for removing large and/or dense stones and staghorn stones. PNL is done via a port created by puncturing the kidney through the skin and enlarging the access port to 1 cm (about 3/8 inch) in diameter. There is no surgical incision. PNL is done under anesthesia and real-time live x-ray control (fluoroscopy). Because […]
- Percutaneous transhepatic cholangiography
Cholangiography, percutaneous transhepatic.