Asphalt Plant Issues in General

Asphalt plants are sources of air pollution that may emit significant levels of both particulate matter and gaseous volatile organic compounds (VOCs). Some VOCs are suspected carcinogens or cancer-causing agents. Seven typical pollutants found at various levels in emissions from asphalt plants:

1. Hydrogen Sulfide (H2S) – a poisonous and colourless gas that is associated with the smell of rotten eggs. People who live near industrial facilities that emit hydrogen sulfide may be exposed to higher levels. It remains in the air for about 18 hrs. High levels of exposure may result in respiratory distress, pulmonary edema, nervous system depression, neurobehavioral effects, tissue hypoxia, cardiovascular effects, unconsciousness and death. Lower level exposures may result in less severe neurological and respiratory effects, such as incoordination, loss of smell, nasal symptoms, sore throat, cough and dyspnea, Some evidence suggests that people with asthma may be overly sensitive and impaired function has been observed in asthmatics exposed to lower levels. Brief exposures can cause serious reactions. Most people recover, but some effects can be permanent or persistent.

2. Benzene – aka Benzol, is a colorless liquid with a sweet odor. It is known as a carcinogen or cancer-causing agent. It enters the body through the lungs, gastrointestinal tract and across the skin. Brief exposure at high levels can cause serious reactions up to and including death. Lower level exposures can cause drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion and unconsciousness. Continuous exposure can lead to anemia and excessive bleeding. It is harmful to the immune system by increasing the chance for infection and perhaps lowering the body’s defense against cancer.

Exposure has been associated with development of a particular type of leukemia called cute myeloid leukemia (AML). Exposure may be harmful to human reproductive organs. It can pass through the mother’s blood to a fetus. It may be harmful to an unborn fetus causing low birth weight, delayed bone formation and bone marrow damage.

3. Chromium – a naturally occurring element found in rocks, animals, plants, soil and in volcanic dust and gases. It cannot be tasted and has no odor. It is present in the environment in several forms, the most common being chromium(0), chromium(III) and chromium(VI) also known as hexavalent chromium. Chromium(VI) and chromium(0) are usually produced by the industrial processes. Chromium(VI) can cause irritation to the nose, such as runny nose, nosebleeds and ulcers and holes in the nasal septum. Chromium(VI) at high levels can damage the nose, and cause cancer. Ingesting Chromium(VI) can cause upset stomach, ulcers, convulsions, kidney and liver damage and even death. Skin contact can cause skin ulcers. Some people are extremely sensitive to Chromium(VI) or Chromium(III). Allergic reactions of severe redness and swelling of the skin have been noted.

4. Formaldehyde – is a nearly colourless gas with a pungent, irritating odor even at very low concentrations (Below 1 ppm). It is a potent sensitizer and a probable human carcinogen or cancer-causing agent. It is an eye, skin and respiratory irritant. Inhalation of vapours can produce narrowing of the bronchi and accumulation of fluid in the lungs. Children may be more susceptible than adults to the respiratory effects of formaldehyde. Even fairly low levels can produce rapid onset of nose and throat irritation, causing cough, chest pain, shortness of breath and wheezing.

5. Polycyclic Aromatic Hydrocarbons (PAHS) are a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage or other organic substances found in coal tar, crude oil, creosote and roofing tar. Health Services agencies have determined that some PAHs may reasonably be expected to cause cancer. Some people who have breathed or touched mixtures of PAHs and other chemicals for long periods of time have developed cancer. Certain PAHs have caused cancer in laboratory animals with breathed in air containing them (lung cancer), ingested them in food (stomach cancer) or had them applied to their skin (skin cancer).

They are found in air attached to dust particles and can enter water through discharges from industrial and wastewater treatment plants where they can move through soil to contaminate groundwater. The PAH contents of plants and animals may be much higher than in the soil and water where they live.

6. Cadmium – is an element that occurs naturally in the earth’s crust. it is a soft, silver-white metal that attaches to small particles in the air. People who live near hazardous waste sites or factories that release cadmium into the air have the potential for exposure. Breathing in high levels can severely damage the lungs and may cause death. Low levels breathed in over long periods of time (years) may result in kidney disease, lung damage, and fragile bones. It is revealed as well that cadmium can cause fewer births, more birth defects than usual, lower birth weights and babies born with behavioural problems and learning disabilities. Multiple health agencies have determined cadmium to be carcinogenic to humans.

7. Arsenic – occurs naturally in soil and minerals. It may enter the air, water and land from wind blown dust and also may get into water from runoff and leaching. It attaches in the air to small particles, which settle to the ground or are washed out or the air by rain. Airborne arsenic can stay in the air for many days and travel long distances. Ultimately, most particles end up in soil or sediment. Children may also be exposed to arsenic by eating dirt, skin contact with soil or water that is contaminated or through inhalation.

Inorganic arsenic is usually found in the environment combined with other elements such as oxygen, chlorine and sulfur. Organic arsenic is arsenic combined with carbon and hydrogen. Long-term oral exposure to inorganic arsenic can cause changes in skin patterns called corns or warts on the palms, soles and torso that may develop into skin cancer. Swallowing inorganic arsenic has been reported to increase the risk of cancer in the liver, bladder, kidneys, prostate and lungs. Multiple health agencies have determined inorganic arsenic to be carcinogenic to humans. Breathing inorganic arsenic will result in a sore throat, irritated lungs and the potential to develop lung cancer. This has been seen mostly in workers exposed to arsenic at smelters, mines and chemical factories, BUT also in residents who live near smelters and chemical factories or waste sites with arsenic. High doses of organic arsenic may result in nerve injury, stomach irritation or other effects. All effects are potentially a concern for children and children may be more susceptible to health effects than adults. Also evidence suggests long-term exposure to arsenic in children may result in lower IQ scores.

Member of the Nova Scotia Road Builder’s Association Robert MacPherson. Scotian Materials Limited. Rob MacPherson. Contact. Address: 100 Venture Run, Suite 103. Dartmouth. #scotianmaterials Halifax quarry quarries aggregate gravel #noFRquarry  Scotian Materials Ltd.