Pyridine


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Introduction

Pyridine is a colorless liquid with an unpleasant smell. It can be made from crude coal tar or from other chemicals. Pyridine is used to dissolve other substances. It is also used to make many different products such as medicines, vitamins, food flavorings, paints, dyes, rubber products, adhesives, insecticides, and herbicides. Pyridine can also be formed from the breakdown of many natural materials in the environment.

Structural diagram: National Institutes of Health


Fate & Transport

Pyridine is primarily released to the environment from industries that make and use this chemical.

Pyridine evaporates into the air very easily.

In the air, it may take several months or years until it breaks down into other compounds.

Pyridine is very soluble in water.

In water or soil, it may be broken down in a few days to a few months by microscopic organisms.

Pyridine sticks to soil particles.

Pyridine probably doesn't build up in plants or animals.

Exposure Pathways

Everyone is exposed to very low levels of pyridine in air, water, and food.

Workers may be exposed in industries that make pyridine or use it to make other products by breathing it in air or by touching it.

People may breathe pyridine when it is released into the air from burning cigarettes and from hot coffee.

People who live near hazardous waste sites or landfills where pyridine exists may be exposed to it by breathing contaminated air or by drinking contaminated water.

Health Effects

Very little information is available on the health effects of pyridine. Animal studies and some limited case reports in people have noted liver damage from exposure to pyridine. Two patients with epilepsy had damage to the liver and kidneys after ingesting some pyridine. We do not know if the pyridine caused these effects because the patients were taking several other medications at the same time. Harmful effects to the liver were also seen in rats and mice that were given pyridine for three months.

Headaches, giddiness, a desire to sleep, quickening of the pulse, and rapid breathing occurred in adults who breathed an unknown amount of pyridine for an unknown length of time. Mild skin irritation and eye irritation were seen in rabbits when pyridine was placed on their skin or in their eyes. We do not know whether pyridine affects the ability of men and women to have children or whether it causes birth defects.

The Department of Health and Human Services, the International Agency for Research on Cancer, and the Environmental Protection Agency (EPA) have not classified pyridine as to its human carcinogenicity. No studies are available in people or animals on the carcinogenic effects of pyridine.

There are medical tests available to measure levels of pyridine in urine and blood. However, these tests are not usually performed in most doctors' offices because special equipment is needed to conduct them. These tests can't tell how much pyridine you were exposed to or if harmful health effects will occur from the exposure to pyridine.

Information excerpted from:

Toxicological Profile for Pyridine 1992

Agency for Toxic Substances and Disease Registry
U.S. Dept. of Health and Human Services