Environmental site assessment (ESA) is a crucial process used to evaluate potential contamination of a site before redevelopment, property transactions, or regulatory compliance. These assessments help identify hazardous materials, ensure environmental safety, and mitigate potential health risks. Various contaminants can be found in soil, groundwater, and air during these evaluations. Understanding the common contaminants detected in environmental site assessment is essential for proper remediation and risk management.
1. Petroleum Hydrocarbons
Petroleum hydrocarbons are among the most frequently detected contaminants in ESAs, particularly in sites associated with gas stations, refineries, and industrial facilities. These contaminants originate from leaks, spills, or improper disposal of petroleum-based products. Petroleum hydrocarbons are divided into:
- Gasoline Range Organics (GRO): Lighter compounds found in gasoline.
- Diesel Range Organics (DRO): Heavier compounds found in diesel fuel.
- Oil Range Organics (ORO): Found in lubricating oils and other heavy petroleum products.
Exposure to petroleum hydrocarbons can cause soil and groundwater contamination, leading to environmental and health concerns. Bioremediation, soil vapor extraction, and chemical oxidation are common remediation methods used to address petroleum contamination.
2. Volatile Organic Compounds (VOCs)
VOCs are a group of chemicals that easily evaporate into the air and can cause significant environmental and health hazards. These compounds are often found in industrial solvents, dry cleaning chemicals, and degreasers. Common VOCs detected during environmental site assessments include:
- Benzene
- Toluene
- Ethylbenzene
- Xylenes (BTEX compounds)
- Trichloroethylene (TCE)
- Tetrachloroethylene (PCE)
VOCs can contaminate both soil and groundwater, posing risks to human health through inhalation, ingestion, and skin contact. Remediation techniques such as air stripping, soil vapor extraction, and activated carbon treatment are used to mitigate VOC contamination.
3. Heavy Metals
Heavy metals are naturally occurring elements that become environmental contaminants through industrial processes, mining, and improper waste disposal. Common heavy metals found in ESAs include:
- Lead (Pb) – Often found in old paint, batteries, and industrial waste.
- Mercury (Hg) – Used in electrical equipment, thermometers, and certain industrial processes.
- Arsenic (As) – Common in pesticides, wood preservatives, and mining operations.
- Cadmium (Cd) – Found in batteries, plastics, and industrial discharges.
Heavy metals persist in the environment and can accumulate in living organisms, leading to serious health effects such as neurological disorders and organ damage. Remediation methods include soil excavation, stabilization, and phytoremediation.
4. Polychlorinated Biphenyls (PCBs)
PCBs are synthetic organic chemicals historically used in electrical transformers, capacitors, and hydraulic systems. Despite being banned in many countries, PCBs still persist in the environment due to improper disposal and leakage from old equipment. These compounds are highly toxic and can cause cancer, immune system damage, and reproductive issues.
PCBs are often detected in soil and water during environmental site assessments. Remediation methods include thermal desorption, incineration, and bioremediation.
5. Polycyclic Aromatic Hydrocarbons (PAHs)
PAHs are a group of organic compounds formed from the incomplete combustion of organic materials, such as coal, oil, wood, and garbage. Common sources include:
- Industrial processes
- Vehicle emissions
- Asphalt production
- Tar and creosote materials
PAHs are known carcinogens and can pose serious health risks through inhalation, ingestion, or skin contact. Remediation techniques such as bioremediation, chemical oxidation, and thermal treatment are used to reduce PAH contamination.
6. Pesticides and Herbicides
Pesticides and herbicides are chemicals used in agriculture, landscaping, and pest control. These substances can leach into groundwater or remain in the soil for extended periods. Common pesticides found in ESAs include:
- DDT (Dichlorodiphenyltrichloroethane) – Banned in many countries but still detected in some areas.
- Atrazine – A widely used herbicide in agriculture.
- Chlordane – Previously used for termite control.
Exposure to these chemicals can lead to neurological damage, endocrine disruption, and cancer. Remediation methods include soil excavation, phytoremediation, and activated carbon adsorption.
7. Asbestos
Asbestos is a naturally occurring mineral once widely used in construction materials, insulation, and fireproofing. When disturbed, asbestos fibers become airborne and pose serious health risks, including lung diseases such as asbestosis and mesothelioma.
Asbestos contamination is often found in older buildings and industrial sites. Proper remediation requires specialized removal procedures, encapsulation, and disposal in regulated facilities.
8. Per- and Polyfluoroalkyl Substances (PFAS)
PFAS, also known as “forever chemicals,” are synthetic compounds found in firefighting foams, non-stick coatings, and water-resistant materials. These chemicals are highly persistent and have been linked to cancer, immune system effects, and hormone disruption.
PFAS contamination is a growing concern in ESAs, particularly near military bases, airports, and industrial facilities. Remediation methods include activated carbon filtration, ion exchange, and advanced oxidation processes.
Conclusion
Environmental site assessments play a critical role in identifying and mitigating contamination risks in soil, water, and air. Understanding the common contaminants found in these assessments helps guide remediation efforts and regulatory compliance. Petroleum hydrocarbons, VOCs, heavy metals, PCBs, PAHs, pesticides, asbestos, and PFAS are among the most frequently detected pollutants. By implementing appropriate remediation strategies, environmental professionals can help restore contaminated sites, protect public health, and ensure sustainable land use practices.
