Some chemicals are hazardous because of their physical properties: they can explode, burn or react easily with other chemicals. Since gasoline can burn and its vapors can explode, gasoline is also hazardous. A chemical can be toxic, or hazardous, or both. Since chemicals can be toxic, it is important to understand how they can affect health.
To determine the risk of harmful health effects from a substance, you must first know how toxic the substance is; how much, and by what means, a person is exposed; and how sensitive that person is to the substance. Some substances are more toxic than others. The toxicity of a substance is described by the types of effects it causes and its potency.
The potency and, therefore, the toxicity of a chemical can be affected by its breakdown within the human body. When a substance is absorbed into the body, its chemical structure may be changed or metabolized to a substance that is more toxic or less toxic. For example, carbon tetrachloride, once a commonly used solvent, is changed by the body into a more toxic chemical that causes liver damage.
For some other chemicals, metabolism changes the chemical into a form that is more easily eliminated by the body. Inhalation breathing of gases, vapors, dusts or mists is a common route of exposure. Chemicals can enter and irritate the nose, air passages and lungs. They can become deposited in the airways or be absorbed by the lungs into the bloodstream. The blood can then carry these substances to the rest of the body.
Ingestion swallowing of food, drink or other substances is another route of exposure. Chemicals that get in or on food, cigarettes, utensils or hands can be swallowed. Children are at greater risk of ingesting substances found in dust or soil because they often put their fingers or other objects in their mouths. Lead in paint chips is a good example. Substances can be absorbed into the blood and then transported to the rest of the body.
Direct contact touching with the skin or eyes is also a route of exposure. Some substances are absorbed through the skin and enter the bloodstream. Broken, cut or cracked skin will allow substances to enter the body more easily. The route of exposure can determine whether or not the toxic substance has an effect. Breathing or swallowing lead can result in health effects, but touching lead is not harmful because lead isn't absorbed through the skin.
The greater the amount of a substance a person is exposed to, the more likely that health effects will occur. Large amounts of a relatively harmless substance can be toxic. For example, two aspirin tablets can help to relieve a headache, but taking an entire bottle of aspirin can cause stomach pain, nausea, vomiting, headache, convulsions or death.
A person's dose can be determined by multiplying the concentration of the chemical times the amount of the water, air, food or soil that a person takes in. For example, the average adult drinks about 2 liters roughly quarts of water and breathes about 20 cubic meters roughly cubic yards of air a day.
If drinking water contains 1 milligram of lead per liter, then the person would take in a total of 2 milligrams of lead in a day. Acute exposure is a short contact with a chemical. It may last a few seconds or a few hours. For example, it might take a few minutes to clean windows with ammonia, use nail polish remover or spray a can of paint. The fumes someone might inhale during these activities are examples of acute exposures.
Chronic exposure is continuous or repeated contact with a toxic substance over a long period of time months or years. If a chemical is used every day on the job, the exposure would be chronic. 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. Inhalation is breathing or inhaling into the lungs. Ingestion is taking something in by mouth. Skin contact occurs when something comes in direct contact with the skin.
Ingestion can be a secondary exposure pathway after skin contact has occurred, if you put your hands in your mouth and transfer the chemical from your hands to your mouth.
The Environmental Protection Agency EPA has developed informational summaries on selected chemicals to describe how people might be exposed to these chemicals and how exposure to them might affect their health. The summaries also explain what happens to the chemicals in the environment, who regulates them, and whom to contact for additional information.
Exposure can occur when people drink contaminated groundwater or surface water, or accidentally ingest it while swimming or showering. Direct skin contact also is an exposure pathway that occurs during activities like swimming and showering. Soil, Sediment, or Dust. People can be exposed to hazardous chemicals in soil, sediment, or dust if they accidentally ingest it, breathe it in, or have direct skin contact.
Children are highly susceptible to these exposure pathways. In their daily activities, children have a tendency to have frequent hand-to-mouth contact and introduce non-food items into their mouths. For more information about hazardous substances, view the EPA webpages. Exposure can occur when people breathe in hazardous chemical vapors or air that is contaminated by hazardous chemicals or dust.
People can be exposed to hazardous chemicals through the food they eat. Food contamination can occur if the food has come into contact with hazardous chemicals. It can also occur further down the food chain such as through eating contaminated fish. For more information, see the DHSS fish advisory. Know the most common toxins that are found in homes today Find safe substitutes, mitigate the hazard or do without the product Ventilate your home regularly, especially during winter months.
Risks Eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment; chronic exposure increases the risk of cancer, liver, kidney and central nervous system damage.
Sources New carpets and home furnishings, interior paints, particle board, plywood and pressed wood products, new plastics and electronics, deodorants, cleaning fluids, varnishes, shampoos and cosmetics, dry cleaned clothing, moth repellents, air fresheners, and during the burning of wood stoves and tobacco products.
Pesticides According to the EPA, 60 percent of herbicides, 90 percent of fungicides and 30 percent of insecticides are known to be carcinogenic. Sources Food some fruits, vegetables and commercially raised meats , household pest control products and sprays, and some chemical lawn treatments which drift or are tracked indoors. To learn about safe, non-toxic lawn care methods, see Natural Lawn Care To learn about non-toxic pest control for inside the home.
Mold and Other Fungal Toxins One in three people have had an allergic reaction to mold. Risks There is no consensus among scientists about the health hazards of mycotoxins. Sources Contaminated buildings, damp areas with frequent temperature changes, airborne particles from furnace blower or air conditioning unit. How To Minimize Exposure: Keep filters clean on heating, ventilating, and air conditioning systems Remove any water sources to mold affected area; dry thoroughly.
Phthalates and PVC Polyvinyl Chloride PVCs contain phthalates, a class of widely used industrial compounds known technically as dialkyl or alkyl aryl esters of 1,2-benzenedicarboxylic acid. Risks Endocrine system damage phthalates chemically mimic hormones and are particularly dangerous to children. Sources Plastic wrap, plastic bottles, plastic food storage containers, which can leach phthalates into our food.
How to Minimize Exposure: Check the label of baby products to ensure they are phthalate-free. When buying plastic products for the home, ask if they contain PVC or phthalates. Avoid eating food stored or microwaved in PVC plastic. Look for the recycling code 3 or V to spot PVC products before they enter your home. Look for PVC-free draperies, window blinds and shades; choose natural fibers such as cotton, linen, wood, bamboo, silk or hemp.
Keep indoor rooms well-ventilated. Dioxins Chemical compounds formed as a result of incomplete combustion processes from commercial or municipal waste incineration, chlorine bleaching of pulp and paper, and from burning fuels like wood, coal or oil. Risks Cancer, reproductive and developmental disorders, chloracne, skin rashes, skin discoloration, and mild liver damage.
Sources Animal Fats — Over 95 percent of dioxin exposure comes from eating commercial animal fats. Reduce consumption of meat and dairy products. Avoid burning materials containing chlorine, such as plastics and wood treated with PCP.
Heavy Metals Metals like arsenic, mercury, lead, aluminum and cadmium, which are prevalent in many areas of our environment, can accumulate in soft tissues of the body.
Sources Drinking water, some seafood, vaccines, pesticides, preserved wood, antiperspirant, building materials, dental amalgams, chlorine plants, lead paints. How To Minimize Exposure: Install water filters. Use cold water for drinking, making tea or coffee, and cooking.
Avoid fish high in mercury, such as king mackerel, tilefish, swordfish, shark, orange roughy, and marlin. If your home was built before , check for lead paint. Risks A growing body of research in laboratory animals has linked PBDE exposure to an array of adverse health effects including thyroid hormone disruption, permanent learning and memory impairment, behavioral changes, hearing deficits, delayed puberty onset, decreased sperm count, fetal malformations and, possibly, cancer.
Sources Some furniture and furniture cushions, drapes, mattresses, pillows, pet beds, carpet and carpet padding, and household electronics and appliances. When purchasing new furnishings and bedding, choose wool or cotton fill over polyester and foam products.
Increase fruits and veggies and reduce animal fats. Reduce dust levels by using damp cleaning methods. Many brands are making a conscious effort to avoid chemicals. This trend will continue when consumers demand more natural products by buying from responsible producers.
The Environmental Working Group is a great resource and offers helpful consumer guides. Learn about them, plus how to protect yourself. Learn more about vaccine availability. Advertising Policy. You have successfully subscribed to our newsletter. Related Articles. Can Weed Killer Cause Cancer?
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