Vaporous Water Contaminants: What's In The Air We Breathe?

Water and groundwater pollutants can be vapors. This process is known as vapor intrusion, which occurs when volatile organic compounds (VOCs) are released into the soil or shallow groundwater and evaporate, producing vapors that travel up through the soil and can enter buildings, degrading indoor air quality. VOC vapors are emitted by dry cleaners, auto-body shops, painting and coating facilities, and gas engines. They can also contaminate groundwater through chemical spills or mishandling, leading to toxic vapors that affect both water and air quality. Aside from VOCs, other sources of water and groundwater pollution include agricultural runoff, industrial waste, and leaking underground fuel tanks. These pollutants can have significant impacts on human health, ecosystems, and freshwater resources, highlighting the importance of prevention, cleanup efforts, and effective water management strategies.

Volatile organic compounds (VOCs)

VOCs are a common contaminant of groundwater, which can occur through chemical spills, leaking underground storage tanks, or improper disposal of chemicals. Once released into the soil or groundwater, VOCs can evaporate, producing vapors that travel up through the soil and can enter nearby buildings, degrading indoor air quality. This process is known as vapor intrusion. VOC vapors can cause various adverse health effects, including eye, nose, and throat irritation, headaches, nausea, and damage to vital organs such as the liver and kidneys.

One example of a VOC that has been detected in groundwater is methyl tert-butyl ether (MtBE). MtBE was previously used as an additive in gasoline to boost octane and reduce air pollution. However, it was found to be a persistent contaminant in groundwater due to its high solubility in water and resistance to degradation by bacteria. While not classified as a human carcinogen, MtBE has been associated with neurological effects and kidney and liver tumors in humans.

The presence of VOCs in groundwater is a significant concern, as it can lead to the contamination of drinking water sources. More than 100 million people in the United States rely on public-supply wells for their drinking water, which can be vulnerable to VOC contamination. To address this issue, various government agencies, such as the Environmental Protection Agency (EPA) and state health departments, work to monitor and regulate VOC levels in groundwater and indoor air quality.

When VOC contamination is suspected or identified, remediation measures can be implemented to remove the chemicals from the soil or groundwater before they enter homes or businesses. Soil vapor vacuum systems, similar to those used in radon mitigation, are commonly employed to suck out and treat the vapors before discharging them into the outdoor air. By taking proactive steps to reduce VOC levels and address contamination, government agencies aim to protect the health and well-being of the public.

Groundwater vapour intrusion

Volatile organic compounds (VOCs) are emitted as vapours into the air by dry cleaners, auto-body shops, painting and coating facilities, and gas engines. VOCs are also a common pollutant at sites where chemical spills or mishandling has contaminated soils. VOCs can leach into groundwater and migrate to drinking-water supply wells. Once in the groundwater, they can generate toxic vapours that move through the soil and can enter buildings, degrading indoor air quality. This process is known as vapour intrusion.

Vapour intrusion refers to the migration of chemical vapours from a subsurface source, such as contaminated soil, groundwater, or utility conduit, into an overlying building or structure. Vapour-forming chemicals that can provide subsurface sources for vapour intrusion include chlorinated volatile organic compounds (VOCs), such as chlorinated solvents, petroleum hydrocarbons, pesticides, polychlorinated biphenyls, elemental mercury, and per- and polyfluoroalkyl substances (PFAS).

When vapour intrusion is suspected, the party responsible for the contamination should investigate. This typically involves testing the soil, groundwater, and soil gas (air trapped between soil particles). This testing helps determine if volatile chemicals might pose an indoor air quality problem. At many contaminated sites, volatile chemical levels are low and are not considered a problem. However, sometimes these levels in the soil, groundwater, or soil gas are high enough to cause concerns about indoor air quality in nearby homes or businesses. When indoor air quality is a concern, samples are often collected inside homes or businesses to determine if the volatile chemical levels are making indoor air unhealthy and whether vapour intrusion is responsible.

Sources of water pollution

Water pollution is a critical issue that jeopardizes human health, the environment, and the economy. It is caused by various sources, including human activities that contaminate bodies of water with harmful substances, leading to decreased water quality and potential toxicity. Here are some of the primary sources of water pollution:

Sewage and Wastewater Treatment:

Sewage and wastewater treatment plants are significant contributors to water pollution. While they are designed to treat and reduce pollutants, aging and overwhelmed systems often release untreated wastewater, containing pathogens, heavy metals, and toxic chemicals, into waterways.

Agricultural Activities:

Agriculture is the leading cause of water degradation worldwide. Fertilizers, pesticides, and animal waste from farms wash nutrients, pathogens, bacteria, and viruses into rivers, streams, wetlands, lakes, estuaries, and groundwater during rainfall. Nutrient pollution, specifically excess nitrogen and phosphorus, is the primary threat to global water quality and can lead to harmful algal blooms.

Industrial and Chemical Pollution:

Factories and industrial facilities release toxic substances, including chemicals and heavy metals, into water sources. This includes industries such as uranium mining, nuclear power plants, and military weapons production, and the coal and gas industries. Improper disposal of radioactive waste can have severe environmental consequences, as uranium is a highly toxic chemical.

Oil and Gasoline Pollution:

Consumer vehicles, such as cars and trucks, contribute significantly to oil pollution in seas and marine environments. Additionally, factories, farms, and cities are land-based sources of oil pollution, with industrial spills and leaks further exacerbating the issue.

Volatile Organic Compounds (VOCs):

VOC vapors emitted by dry cleaners, auto-body shops, painting facilities, and gas engines can contaminate soils and leach into groundwater. VOCs in the air can also contribute to ground-level ozone formation. Once in the groundwater, they can generate toxic vapors that migrate through soils and buildings, leading to indoor air quality issues through a process known as vapor intrusion.

It is important to address these sources of water pollution through proper waste disposal, treatment systems, and sustainable practices to protect water resources and mitigate the negative impacts on human health, ecosystems, and the economy.

Health risks of vapour intrusion

Vapour intrusion occurs when vapour-forming chemicals migrate from a subsurface source into an overlying building. This process, known as vapour intrusion, can result in the contamination of indoor air and the degradation of indoor air quality. Volatile organic compounds (VOCs) are a common type of pollutant that can lead to vapour intrusion. These compounds are emitted by sources such as dry cleaners, auto-body shops, and painting facilities, and can contaminate soil and groundwater. Once in the groundwater, VOCs can generate toxic vapours that move through the soil and enter buildings through cracks, crawl spaces, and openings.

The health risks associated with vapour intrusion depend on the specific chemicals involved and the level of exposure. In general, exposure to VOC vapours can cause a range of health issues, including eye, nose, and throat irritation, headaches, loss of coordination, nausea, and damage to vital organs such as the liver, kidneys, and central nervous system. Some VOCs are also suspected or known to be carcinogenic.

The Washington State Department of Health recommends investigating vapour intrusion when it is suspected to be causing indoor air quality issues. This typically involves testing the soil, groundwater, and soil gas to determine the presence and levels of volatile chemicals. If high levels of volatile chemicals are detected, mitigation measures such as soil vapour vacuum systems can be installed to remove the chemicals before they enter homes or businesses.

While vapour intrusion can pose health risks, it is important to note that the levels of volatile chemicals are typically low in indoor air, and the symptoms associated with exposure are usually temporary and resolve when individuals move into fresh air. However, prolonged exposure to low levels of volatile chemicals over many years may still carry a small health risk, and government agencies often take precautionary measures to reduce even low levels of these chemicals.

Preventing and cleaning up water pollution

Vapors from chemical spills or mishandling can contaminate the soil and leach into groundwater. These vapors can also migrate to nearby buildings, degrading indoor air quality and posing risks to human health. This process is known as vapor intrusion and can occur through cracks in the foundation or openings for utility lines.

To prevent vapor intrusion, it is essential to address the source of pollution and ensure proper handling and storage of chemicals to avoid spills and leaks. This may involve implementing controls on toxic substances and improving storage infrastructure.

When vapor intrusion is identified, installing a vapor mitigation system can be an effective solution. These systems create a vacuum under the building to prevent soil vapors from entering. Additionally, regular assessment and reevaluation of sites, even those previously considered closed, are crucial to address any potential vapor intrusion risks.

Cleaning up water pollution caused by vapors can be challenging and time-consuming. Natural processes that cleanse water can take years, decades, or even centuries. Technological processes, such as air stripping and filtration through activated carbon filters, can be employed but may still require many years to fully remediate a site.

To prevent and clean up water pollution, it is essential to remove the source of pollution to prevent further contamination. This can involve actions such as digging up leaking oil tanks or implementing controls on toxic substances. Upgrading wastewater treatment facilities can also help reduce water pollution. Additionally, pollution trading programs can provide incentives for companies to reduce pollution, as seen in Ontario's smog trading program.

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