Environmental Remediation Specialists

• Environmental Document Preparation - CE
• ESA Screening, Phase I ESA and Phase II ESA

• Spill Incident
• Release from underground vessel or system
• Regulatory requirement
• Liability concerns related to a property transaction
  • Findings of a Phase One Environmental Site Assessment
  • Data gap identified in a Phase One Environmental Site Assessment
  • A REC identified in a Phase One Environmental Site Assessment

When investigating for Dense Non-Aqueous Phase Liquids (DNAPLs), one must consider the following:

• Not likely to observe free product in subsurface
• Must not create new vertical migration pathways
• Need to be able to discretely sample multiple vertical zones

If you have questions regarding DNAPLs, contact August Mack Environmental at 800.579.0770 and ask to speak to one of our environmental remediation specialists.

• Immiscibility with water - they form separate ‘phases’, eg. Oil & water
• Low solubilities - DNAPL can’t dissolve quickly in groundwater: it may persist for decades before dissolving
• Relatively high densities - DNAPLs are denser than water, and can therefore sink beneath the water table, polluting the full thickness of an aquifer
• Low viscosities - allows rapid subsurface migration
• Toxicity - Many DNAPLs are suspected or...

Understanding Light Non-Aqueous Phase Liquid (LNAPL) is important for the following reasons:

• LNAPL is common problem: several hundred thousand petroleum underground storage tanks (USTs) in the United States.
• LNAPL in soil/groundwater serves as continuing source of contamination.
• Can have dangerous physical characteristic – e.g., flammable vapors.
• Can migrate rapidly in subsurface(vertically and horizontally).
• Many LNAPLs are toxic and can cause cancer (e.g., benzene).

Vapor intrusion (VI) is the migration of volatile chemicals from the subsurface into overlying buildings. The chemicals associated with VI are the following:

• Volatile Organic Compounds (VOCs)
  • Chlorinated Hydrocarbons, e.g., TCE, PCE, 1,2-DCA, Vinyl Chloride, etc. – drycleaners, manufacturers
  • Benzene & Other Volatile Petroleum Constituents
• Methane – in certain areas of U.S. (e.g., LA Basin)
• Semi-Volatile Organic Compounds (SVOCs) - Less Common

House Enrollment Act (HEA) 1162 requires the Indiana Department of Environmental Management (IDEM) to consider risk-based solutions while evaluating environmental closures. Risk-based closures can include several approaches for example:

• Applying pre-approved closure levels
• Determining site-specific closure levels
• Considering risk of exposure

One of the in-situ remedial technologies available is air sparging (AS). This remedial technology reduces the concentrations of volatile constituents in soils and groundwater by the injection of contaminant-free air into the subsurface saturated zone. It produces a phase transfer of hydrocarbons from a dissolved sate to a vapor phase. Then, the air is vented through the unsaturated zone. It is commonly used with soil vapor extraction (SVE).

The advantages of air sparging are the following:

• Proven...

The in-situ remediation technology of dual phase extraction (DPE) is also known as multi-phase extraction or vacuum-enhanced extraction. During DPE, the following occurs:

• DPE uses vacuums to remove contaminated groundwater, free-phase product and contaminated vapors from soils.
• Extracted liquids and vapor are treated and collected for disposal.
• DPE pulls air through pore space in contaminated soils and pulls contaminated groundwater and free product from the same well location.
• Requires permits for...

In the in-situ remedial technology of soil vapor extraction (SVE), the following occurs:

• Vacuum is applied to the unsaturated zone through extraction wells.
• Vacuum causes movement of vapors toward extraction wells.
• Volatile constituents are removed through the extraction wells.
• The extracted vapors are discharged to the atmosphere.

• Proven performance; readily available equipment; easy installation; agency approved.
• Minimal disturbance to site...

If a confirmed release has occurred, Environmental Protection Agency (EPA) regulations require that an appropriate cleanup response, or Corrective Action, be conducted

The purpose of the corrective action process is to ensure that releases of petroleum and regulated substances do not threaten human health and the environment. The steps in the process are:

1. Release discovery and reporting
2. Initial Abatement
3. Investigation
4. Corrective Action
5. Incident Closure/No Further Action

An underground storage tank (UST) Systems may be closed voluntarily if owner or operator chooses, or by mandate if system is not in compliance with regulations.

The guidelines for a temporary UST closure are:

• Corrosion protection must be maintained
• If UST is temporarily closed for 3-12 months:
• Leave vent line open
• Cap and secure all other lines, pumps, equipment, etc.

Keep in mind that if an UST is temporarily closed for more than 12 months it must be permanently closed.

The guidelines for a permanent...

Spills, or other releases of hazardous constituents to the environment, can have many forms including emergency response situations like fuel releases to a ditch during an accident, a release of petroleum from an underground storage tank (UST) or a release associated with waste storage. Regardless of the nature of the release, once a release has been identified, the responsible party must take actions to prevent further release, investigate the nature and extent of impacts and if warranted,...

• Reduce the chance of releases from USTs (Construction & Installation)
• Detect leaks and spills when they do occur (Design)
• Secure a prompt cleanup (Notification)

• Secondary containment and interstitial monitoring
• Aut...