How can toxins enter your body

Vapours are formed from products that exist as solids or liquids under normal temperature and pressure conditions. Products that do not exist as solids or liquids at normal temperatures and pressures are called gases. Gases as well as vapours can contaminate the workplace air. In some instances, an industrial process might produce tiny liquid droplets that are able to float in the air.

These droplets are called mists. Mists are formed by gases that condense into small liquid droplets in the air. Alternatively, mists may form by breaking up, splashing, or atomizing a liquid. Examples include acid mists from electroplating, oil mists from cutting and grinding, or paint spray mists from painting operations. Other workplace processes can generate tiny solid particles which are light enough to float in the air, and these particles are referred to as dusts, fumes and smoke.

Dusts are solid particles often generated by some mechanical or abrasive activity. They are usually heavy enough to settle slowly to the ground. Fumes are very tiny solid particles which can remain airborne, and are formed when a heated metal has evaporated in the air and then condensed back to a solid form. Fumes can occur in welding operations. Smoke is carbon or soot from burning. Smoke particles can settle or remain airborne depending on their size.

Chemicals which pass through the skin are nearly always in liquid form. Solid chemicals and gases or vapours do not generally pass through the skin unless they are first dissolved in moisture on the skin's surface. The skin is the second most common route by which occupational chemicals enter the body.

The skin consists essentially of two layers, a thin, outermost layer called the epidermis and a much thicker underlayer called the dermis. The epidermis consists of several layers of flat, rather tightly-packed cells which form a barrier against infections, water, and some chemicals.

This barrier is the external part of the epidermis. It is called the keratin layer, and is largely responsible for resisting water entry into the body. It can also resist weak acids but is much less effective against organic and some inorganic chemicals.

The keratin layer contains fat and fat- like substances which readily absorb chemicals which are solvents for fat, oil, and grease. Organic and alkaline chemicals can soften the keratin cells in the skin and pass through this layer to the dermis, where they are able to enter the blood stream. Areas of the body such as the forearms, which may be particularly hairy, are most easily penetrated by chemicals since they can enter down the small duct containing the hair shaft.

Chemicals can also enter through cuts, punctures or scrapes of the skin since these are breaks in the protective layer.

Contact with some chemicals such as detergents or organic solvents can cause skin dryness and cracking. There can also be hives, ulcerations or skin flaking. All these conditions weaken the protective layer of the skin and may allow chemicals to enter the body. Chemicals can vary enormously in the degree to which they penetrate the skin. Some solvents may soften the keratin layer but are not believed to penetrate much further unless there is prolonged skin contact.

Other chemicals can readily pass through the epidermis and subsequently enter the blood stream. Some chemicals are so corrosive they burn holes in the skin, allowing entry for infection or other chemicals. In some instances, chemicals may enter the body by accidental injection through the skin. This situation may occur in hospital settings or in industrial hole-punching or injection processes.

Once in the blood stream, these chemicals can be transported to any site or organ of the body where they may exert their effects. Although eye splashes or eye contamination by workplace chemicals is fairly common, chemicals usually do not enter the body this way. Small amounts of chemicals may enter by dissolving in the liquid surrounding the eyes, and larger, but probably not significant amounts, may enter the eyes if they are splashed with chemicals.

The eyes are richly supplied with blood vessels and many chemicals can penetrate the outer tissues and pass into the veins. Chemicals should never be tasted; and pipetting and siphoning of liquids should never be done by mouth. Contact with the skin is a frequent mode of chemical injury.

A common result of skin contact is a localized irritation, but an appreciable number of materials are absorbed through the skin with sufficient rapidity to produce systemic poisoning.

The main portals of entry for chemicals through the skin are the hair follicles, sebaceous glands, sweat glands, and cuts or abrasions of the outer layers of the skin. The follicles and glands are abundantly supplied with blood vessels, which facilitates the absorption of chemicals into the body. Contact of chemicals with the eyes is of particular concern because these organs are so sensitive to irritants. Few substances are innocuous in contact with the eyes; most are painful and irritating, and a considerable number are capable of causing burns and loss of vision.

Alkaline materials, phenols, and strong acids are particularly corrosive and can cause permanent loss of vision. Also, eyes are very vascular and provide for rapid absorption of many chemicals.

Skin and eye contact with chemicals should be avoided by use of appropriate protective equipment. Over time, some chemicals, such as PCBs and lead, can build up in the body and cause long-term health effects. Chronic exposures can also occur at home.

Some chemicals in household furniture, carpeting or cleaners can be sources of chronic exposure. Chemicals leaking from landfills dumps can enter the groundwater and contaminate nearby wells or seep into basements.

Unless preventive measures are taken, people may be exposed for a long time to chemicals from their drinking water or indoor air. All people are not equally sensitive to chemicals, and are not affected by them in the same way. There are many reasons for this. We don't know all the effects of exposure to every chemical.

We learn about the health effects of many chemicals from human exposures and animal studies. Sometimes a human population that has been exposed to a toxic substance usually at work or from an environmental source is compared with a population that has not been exposed. If the exposed population shows an increase in a certain health effect, that health effect may be related to the chemical exposure. However, these studies often cannot determine the exact cause of a health effect.

A chemical exposure can produce a health effect directly at the site of contact local or elsewhere in the body systemic , and that effect can be either immediate or delayed. Every organ system has different functions and physical characteristics. So the effect of chemicals on each system has to be evaluated slightly differently. As an example, consider three ways that chemicals can affect one system: the reproductive system.

First, chemical exposure can affect a man's or woman's reproductive system by making the production of normal sperm or eggs more difficult. Second, the chemical may act directly on an unborn baby fetus. Since chemicals can be transferred from the mother's blood to the unborn baby's blood, the fetus can be affected when the mother is exposed to certain chemicals. A pregnant woman who drinks alcohol can have a baby with fetal alcohol syndrome. The health effects can range from birth defects to learning disabilities.

And finally, some chemicals can have indirect effects on the development of the fetus. For example, smoking during pregnancy can reduce the amount of oxygen to the fetus. The lack of oxygen can affect the baby's growth. Not all chemical exposures affect reproduction, but it is best to minimize exposure to all toxic substances during pregnancy. Delayed health effects may take months or years to appear and can result from either acute or chronic exposure to a toxic substance. The delay between the exposure and the appearance of health effects is called the latency period.

Delayed health effects can be reversible or permanent. Permanent effects don't go away when the exposure stops. For example, breathing asbestos over a period of time may cause lung disease. Once the lung disease begins, it will continue even if the exposure stops or decreases.

Cancer is an example of a delayed health effect. Cancer is the uncontrolled growth and spread of abnormal cells in the body. There are many kinds of cancer. Cancer can be caused by a number of things, including exposure to toxic substances, ultraviolet sunlight and ionizing radiation. Exposure to some chemicals, such as benzene and asbestos, can produce cancer in humans.

Some chemicals produce cancer in animals, but whether they will in humans is unknown. Because cancer may not appear until 5 to 40 years after exposure, determining the cause of cancer is difficult. Even though chemicals we use or are exposed to every day can be toxic, you can protect yourself and your family from chemical exposures.

No matter how toxic a substance may be, if you are not exposed to the substance, it cannot affect your health. The important rule to remember is: minimize your exposure. Public and university libraries, professional organizations or citizen groups may also be helpful.

The more you know about toxic substances, the more you can reduce exposure. What you know can help you! Navigation menu. What You Know Can Help You - An Introduction to Toxic Substances Armed with some basic facts about toxic substances, you can reduce your exposure to chemicals and lower the chance of harmful health effects.

What is a toxic substance? Health effects: toxic or hazardous? How can toxic substances cause harm? Toxicity Some substances are more toxic than others. Types of Effects: Different chemicals cause different effects. For example, Chemical A may cause vomiting, but not cancer. Chemical B may have no noticeable effects during exposure, but may cause cancer years later. Potency: Potency strength is a measure of a chemical's toxicity.

A more potent chemical is more toxic. For example, sodium cyanide is more potent than sodium chloride table salt since swallowing a smaller amount of cyanide can poison you. Exposure: A chemical can cause health effects only when it contacts or enters the body. Routes of Exposure: Exposure to a substance can occur by inhalation, ingestion or direct contact.

Dose: The amount of a substance that enters or contacts a person is called a dose.