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Frequently Asked Questions

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GENERAL

How do you get a site off of the priority list?
A facility that has been listed on the Comprehensive Environmental Cleanup and Responsibility Act (CECRA) Priority List must go through the CECRA process in order to be removed from the list. A description of the CECRA program can be found at the following link: http://deq.mt.gov/StateSuperfund/. The Voluntary Cleanup and Redevelopment Act (VCRA) is an option separate from the CECRA process, but still within CECRA that can be used to clean up a facility. Information about VCRA is available at the following link: http://deq.mt.gov/StateSuperfund/vcra.mcpx. A flow chart of the State Superfund process, which includes information about both CECRA and VCRA can be found at the following link: http://deq.mt.gov/StateSuperfund/PDFs/statesuperfundchart.pdf.

Do I have to perform a Fate and Transport Analysis?
No, you have the option to use screening levels as cleanup levels so that a Fate and Transport Analysis is not necessary.  However, if you choose to calculate site-specific cleanup levels, DEQ will also require the use of fate and transport modeling of the soil leaching to groundwater pathway to determine a cleanup level for this pathway (please refer to the Fate and Transport FAQ. ) In addition, site-specific cleanup levels require the use of standard EPA human health risk assessment guidance (EPA 1999, 1998a, 1997b, 1992, 1991a-c, and 1989) and/or, as applicable, standard EPA ecological risk assessment guidance (EPA 2000a, 1998b, and 1997a) using assumptions acceptable to DEQ.  Please see the Risk Assessment/Analysis section of the FAQs for additional information. It is important to identify as early in the CECRA process as possible if you are going to calculate site-specific cleanup levels, so that the data for fate and transport can be collected during the RI.

Will the state compensate me for contamination on my property that was caused by someone else?
Neither the Comprehensive Environmental Cleanup and Responsibility Act (CECRA) or the Water Quality Act (WQA) provide for compensation of property owners, no matter who caused the contamination to be placed on the property.

Is there an example of data validation requirements that I can use?
Yes, view an example of a data validation guidelines used by the DEQ.

Does DEQ/SRS have any examples of an institutional control?
DEQ requires the placement of institutional controls if a facility is not remediated to unrestricted use. One common institutional control allowed by DEQ is a restrictive covenant. See the following Restrictive Covenant example document.

For facilities in remedial design, are there examples of what should be included in a 30% (Basis of Design), 50%, 90%, or 100% Design Document?
Please click on the link Design Document Components to find examples of the information that should be contained in design documents.

How does one go about doing a voluntary cleanup?
The purposes of the Voluntary Cleanup and Redevelopment Act (VCRA) are to provide for the protection of the public health, welfare, and safety and of the environment and to foster the cleanup, transfer, reuse, or redevelopment of facilities where releases or threatened releases of hazardous or deleterious substances exist. VCRA is further intended to permit and encourage voluntary cleanup of facilities where releases or threatened releases of hazardous or deleterious substances exist by providing interested persons with a method of determining what the cleanup responsibilities will be for reuse or redevelopment of existing facilities. VCRA is meant to encourage and facilitate prompt cleanup activities, eliminate impediments to the sale or redevelopment of facilities where releases or threatened releases of hazardous or deleterious substances exist, and minimize administrative processes and costs. 

The complete VCRA guide is located at:  http://www.deq.mt.gov/StateSuperfund/vcraguide.mcpx.  This guide identifies the requirements of VCRA and provides a suggested format for voluntary cleanup plans (VCPs). The primary target audience for this guide is the qualified environmental professional who is preparing the VCP. However, the guide is also designed to provide information to all applicants or potential applicants regarding the VCRA process.

 

 

SOIL

 

What is considered surface soil?
DEQ/SRS considers surface soil to be anything from 0-2 feet below ground surface (bgs).

How do we screen soil?
For initial screening of contaminants of concern, please refer to the Screening Frequently Asked Questions (FAQs) for guidance. The flow chart of the soil screening process is also a helpful tool in screening soils.

How should moisture data be reported for soil samples?
All soil and sediment data must be reported on a dry-weight basis.   Moisture percentage must also be determined and reported on the laboratory data reports. Please see the following FAQ on dry-weight conversion.

How is the as-received (wet-weight) result converted to dry-weight for soil samples? 
The dry-weight is converted from wet-weight by the following formula:

Dry Weight Result = As-Received Result/(1- % moisture)

Example:

If you have a TEH value of 300 mg/kg, and a moisture of 14%, the calculation would be:

300 mg/kg/(1-0.14) = 349 mg/kg dry weight

How do we deal with metals in background soils?
Metals are naturally occurring in the environment. If metal concentrations exceed screening levels or you suspect they may exceed screening levels, it is appropriate to collect facility-specific background samples from unimpacted areas that are representative of natural conditions. You may also propose established literature values for background concentrations. In some cases, background concentrations may exceed screening levels. In that case, background concentrations may be used in place of screening levels. Consultation with DEQ is recommended.

What are appropriate sampling depths for surface soils?
As a general rule, samples are collected from 0-6 inches below ground surface (bgs) in source areas and from 0-2 inches bgs in areas of aerial deposition. Additional sampling should be conducted within the 0-2 feet zone in order to determine how much of the soil profile is contaminated and must be removed, etc. However, samples compositing the entire 0-2 feet zone should not be collected, as more discreet intervals provide better information.

What depths of contamination need to be evaluated for a construction worker scenario?
Construction workers would be expected to be exposed to both surface (0-2 feet below ground surface (bgs)) and subsurface (2-10 feet bgs) soil. Therefore, it is appropriate to evaluate construction worker exposure to both surface and subsurface soils. If cleanup levels protective of construction workers are lower than those for other surface soil receptors, the lower cleanup levels would also apply to surface soil.

Do I need to cleanup subsurface soils greater than 10 feet as long as there are no leaching to groundwater or vapor intrusion issues?
In addressing the direct contact risk to the construction workers at CECRA facilities, DEQ typically requires remediation of subsurface soil to depths of 10 feet. However, there are some sites where contamination extends deeper than 10 feet and there may be situations where future building at the site could result in footings or foundations greater than 10 feet. In order to ensure protectiveness for direct contact as well as to provide notice to future purchasers of the property, a site with contamination left in place deeper than 10 feet must also have an institutional control to limit excavation to 10 feet. (The other option is to remediate subsurface soil to depths greater than 10 feet.) However, the placement of an institutional control does not address those facilities with leaching to groundwater or vapor intrusion considerations.

I see the DEQ has developed a generic action level for arsenic in surface soil (0-2' deep), but what is the arsenic cleanup level for subsurface soil (>2' deep)?
DEQ has used an excavation scenario like that included in Montana's Risk-Based Corrective Action Guidance for Petroleum Releases to calculate a level of arsenic of 300 mg/kg in subsurface soil that is protective of typical construction/utility workers. This level may be appropriate for use at facilities where it can be demonstrated that groundwater is not being impacted by arsenic. A site-specific risk analysis, including site-specific bioavailability evaluation, may be appropriate for some facilities.

Can I use the EPA RSL commercial/industrial screening level for lead as a generic screening level for subsurface soil (>2' deep)?
Using the US EPA Adult Lead model, DEQ has determined that subsurface soil with lead concentrations of 800 mg/kg, the commercial/industrial US EPA Regional Screening Level, is generally protective for construction/excavation workers. Please note that while the commercial/industrial screening level is protective of construction/excavation workers for lead, this approach is not the case for all other COCs. Except for Lead and Arsenic, DEQ uses the EPA RSL residential screening level to initially screen all soils (both surface and subsurface).

Why do I have to compare soil sample results to RESIDENTIAL cleanup levels when the site is an INDUSTRIAL facility? What happens if the site meets INDUSTRIAL but not RESIDENTIAL cleanup levels?
The future use of the facility cannot be guaranteed, even if the current and past uses of the facility were industrial. Therefore, DEQ/SRS requires that soil concentrations be screened against residential U.S. Environmental Protection Agency (EPA) regional screening levels (RSLs), as well as industrial. If the concentrations exceed residential RSLs, but not industrial RSLs, then DEQ may require that institutional controls (i.e., deed restrictions, etc.) be placed on the property to ensure that it will not be used for residential uses in the future.

When collecting surface soil samples for lead analysis, why am I being required to sieve the samples to 250 microns (No. 60 sieve) and analyze the finer fraction?
Previous site investigations across the country have demonstrated a tendency for lead contamination to be concentrated in the finer (dust sized) fraction of soil. It is also from this size fraction that most exposure to humans occurs. Therefore, at facilities where lead is likely to be a contaminant of concern, DEQ requires analysis of the finer fraction.

Since sieving samples adds additional time and cost to the investigation, during an initial site characterization, a portion of the samples could be laboratory analyzed in both sieved and bulk form. DEQ requires that a representative number of samples be laboratory analyzed in both forms. The samples selected for both analyses must account for different sources, lithology, or other characteristics that could influence the ratio between sieved and unsieved sample concentrations. DEQ requires analysis of both types of samples for 100% of samples in samples sets of less than 20 samples, at least 20 samples in sample sets of 20 - 100 samples, and 20% of the samples in sample sets greater than 100 samples. If possible, samples analyzed in both forms should be collected from areas of low, medium, and high levels of lead contamination (XRF analysis can be a useful tool for this). Once the two sets of data are available a ratio of sieved analysis to bulk analysis can be calculated for each sample. Then a 95% upper confidence level (UCL) on the mean of all the ratios can be calculated. The UCL of the ratios may then be used as a factor that can be applied to historic, current and future bulk samples collected for characterization or confirmation sampling without the need for further sieved sampling. Please refer to the following EPA Guidance documents for further information: EPA Short Sheet On Lead Sampling and the Superfund Lead-Contaminated Residential Sites Handbook. For information on screening levels for lead in soil, please refer to the Screening FAQ. DEQ may also require sieving of samples for other analysis of other compounds such as other metals or dioxins and furans as appropriate.

For screening purposes, can an XRF be used instead of laboratory analysis for metals soil samples and how should the data be evaluated?
If XRF data is collected, the size of the data set needs to be considered. Typically, at least 10% of all samples analyzed using an XRF should also be laboratory analyzed to ensure the quality of the XRF results and reliability of the data (this does not preclude the evaluation of 20% of the samples collected for the lead finer fraction analysis explained above). DEQ recommends that samples selected for laboratory analysis be focused around data that is near the action level, with a minimum of 25% of the XRF high and low range concentration samples sent to the laboratory for analysis. For smaller data sets, laboratory analysis only may be more appropriate. The relative percent difference (RPD) of each XRF/laboratory sample pair should be calculated. The average RPD of the XRF/laboratory sample pairs should not exceed 35% (per EPA National Functional Guidelines for Inorganic Data Review, October 2004). A graph showing the correlation between the XRF and laboratory results should be provided and the correlation coefficient for the results should be 0.7 or greater for the XRF data to be considered screening level data (per EPA Method 6200 [XRF]). A discussion that identifies the factors that may affect the strength of the correlation and why it is or is not indicative of a strong relationship between the two data sets should also be provided (e.g., false negatives or positives, outliers, correlated residuals, XRF sample interference, elevated detection limits, bias).

The project-specific SAP/QAPP should cover XRF data collection, XRF and lab quality control requirements (including XRF calibration), collection of laboratory samples, comparison of XRF to laboratory data, and a detailed description of the XRF/laboratory data correlation, as described above. The XRF/laboratory data comparison and correlation should also be discussed as part of the overall data quality for the investigation.

 

 

SOIL VAPOR INTRUSION

 

Download soil vapor intrusion FAQ as a PDF (148K)

What is soil vapor intrusion?
The phrase "soil vapor intrusion" refers to the process by which volatile chemicals move from beneath the ground into the indoor air of overlying buildings.

Soil vapor, or soil gas, is the air found in the spaces between soil particles. Because the air pressure inside may be lower than in the soil, this vapor may enter buildings through cracks in slabs or basement floors and walls, and through openings around sump pumps or where pipes and electrical wires go through the foundation. Heating, ventilation or air-conditioning systems may reduce the air pressure inside, drawing soil vapor into buildings.

Chemicals that readily evaporate or vaporize are called "volatile chemicals." Volatile chemicals include volatile organic compounds (VOCs). Subsurface sources of volatile chemicals may include contaminated soil and groundwater, broken pipes, or buried wastes. If soil vapor is contaminated and enters a building as described above, the air quality inside the building may be affected.

When contaminated vapors are present nearby or under the foundation of the building, vapor intrusion is possible. Soil vapor can enter a building whether the building is old or new, and whether the building has a basement, a crawl space, or is on a slab (as illustrated in the figure below).

Soil Vapor Intrusion Entryways
Figure courtesy NYSDOH, October 2006

How do we screen contaminated vapors?
For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance.

How could I be exposed to chemicals through soil vapor intrusion?
Humans can be exposed to contaminated soil vapor when vapors from beneath a building are drawn through cracks and openings in the foundation and mix with the indoor air. These vapors may be inhaled along with the indoor air.

Both vapor intrusion that is documented in an occupied building and potential future vapor intrusion (when volatile chemicals are present, or are accumulating, in the vapor phase beneath a building but have not affected indoor air quality) must be evaluated. Potential vapor intrusion may also exist when there is a chance that contaminated soil vapors may move to existing buildings not currently affected or when there is a chance that new buildings will be built over existing subsurface vapor contamination.

In general, inhaling a volatile chemical does not necessarily mean that a person will experience health effects. Whether or not a person experiences health effects depends on several factors, including the length of time a person is exposed, the number of times a person is exposed, the toxicity of the volatile chemical, and person’s sensitivity to the chemical.

Is contaminated soil vapor the only source of volatile chemicals in my indoor air?
No. Volatile chemicals may also be found in certain household products such as paints, paint strippers and thinners, mineral spirits, glues, solvents, cigarette smoke, aerosol sprays, mothballs, air fresheners, new carpeting or furniture, hobby supplies, lubricants, stored fuels, refrigerants and recently dry-cleaned clothing.

Indoor air may also become affected when outdoor air containing volatile chemicals enters your home. Volatile chemicals may be present in outdoor air due to their widespread use. Gasoline stations, dry cleaners, and other commercial/industrial facilities are also potential sources of VOCs to outdoor air.

How is soil vapor intrusion investigated at sites contaminated with volatile chemicals?
The process of investigating soil vapor intrusion typically requires more than one set of samples to determine the extent of vapor contamination. Several different types of environmental samples may be collected: soil vapor samples, sub-slab vapor samples, samples from the air found in crawl spaces, indoor air samples, and outdoor air (sometimes referred to as "ambient air") samples.

Soil vapor samples are collected to characterize the nature and extent of vapor contamination in the soil in a given area. They may be collected before sub-slab vapor and/or indoor air samples to help identify buildings or groups of buildings that need to be sampled. Soil vapor samples are used to determine the potential for vapors to accumulate beneath buildings. Soil vapor samples are not the same as soil samples.

Sub-slab vapor samples are collected to characterize the nature and extent of vapor contamination in the soil immediately beneath a building with a slab. In buildings without a slab, crawl space air and/or soil gas samples may be collected below the building. Sub-slab vapor results are used to determine the potential for vapor intrusion.

Indoor air samples are collected to characterize the nature and extent of vapors within a building. Indoor air sample results help to evaluate whether vapors are currently migrating in to a building. They are also compared to sub-slab vapor and outdoor air results to help determine where volatile chemicals may be coming from (indoor sources, outdoor sources, and/or beneath the building).

Outdoor air samples are collected to characterize site-specific background air conditions. Outdoor air results are used to evaluate the extent to which outdoor sources, such as automobiles, lawn mowers, oil storage tanks, gasoline stations, commercial/industrial facilities, and so forth, may be affecting indoor air quality. However, the presence of a contaminant in the outdoor air does not necessarily mean that the contaminant will be present in indoor air.

What should I expect if indoor air samples are collected in my home?
You should expect the following:

  • Indoor air samples are generally collected from the lowest-level space in a building, such as a basement. They are often collected during cold weather when the building is heated and the ground is frozen. Indoor air samples may also be collected from the first floor of living space, or any other area of potential concern. Indoor air samples are used to determine if vapors are inside buildings.

     
  • Sub-slab vapor and outdoor air samples are usually collected at the same time as indoor air samples to help determine where volatile chemicals may be coming from (indoor sources, outdoor sources, and/or beneath the building).

     
  • Some sampling may be performed during warmer weather. For example, soil gas or sub-slab vapor samples without indoor air or outdoor air samples may be collected to identify buildings and areas where comprehensive sampling is needed during the heating season.

     
  • An indoor air quality questionnaire and building inventory will be completed with your input. The questionnaire includes a summary of the building's construction characteristics; the building's heating, ventilation and air-conditioning system operations; and potential indoor and outdoor sources of volatile chemicals. The building inventory describes products present in the building that might contain volatile chemicals. These products may be temporarily removed from the building while it is being sampled with homeowner consent.

 

Should I do anything differently than normal at home during or before the sampling?
At least 48 hours prior to and during the collection of the indoor air sample (which takes 24 hours), please take the following actions to minimize background concentrations of VOCs:

  • Try to avoid opening windows or keeping doors open
  • Avoid operating ventilation fans or air conditioning if possible
  • Please avoid using air fresheners or odor eliminators
  • Please do not smoke indoors
  • Please do not use paint, solvents, or varnishes
  • Please do not use cleaning products such as bathroom cleaners, furniture polish, appliance cleaners, all-purpose cleaners, floor cleaners, or gun cleaners
  • Please try to minimize the use of cosmetics such as hair spray, nail polish, nail polish remover, perfume, cologne, etc.
  • Please do not apply pesticides
  • Please do not store containers of gasoline, oil, petroleum-based or other solvents within the house or use them in an attached garage
  • Please do not operate or store automobiles in an attached garage if possible

It is important to note that many building materials contain VOCs, such as plywood flooring, latex paint, sheet vinyl flooring and new carpeting, among others. Obviously, it is not practical to remove these potential indoor sources of VOCs from homes. However, removing all identified household products which may contain VOCs and adhering to this list of steps to take prior to and during sampling will help minimize the background levels of VOCs in your house or business.

 

What happens if soil vapor contamination or soil vapor intrusion is identified during investigation of a site?
Depending on the investigation results, DEQ may require additional sampling or mitigation, in addition to requiring cleanup of the subsurface sources. Additional sampling would be performed to determine the extent of soil vapor contamination and to verify questionable results. Mitigation is action that is taken to minimize exposures to indoor air contamination while cleanup is occurring. Mitigation may include sealing cracks in the building's foundation and installing a sub-slab depressurization system beneath the building (similar to a radon mitigation system).

What is a sub-slab depressurization system (also known as a mitigation system)?
A sub-slab depressurization system essentially prevents vapors beneath a slab from entering a building. A low amount of suction is applied below the foundation of the building and the vapors are vented to the outside (see figure below). Mitigation systems are inspected to insure that they are effective and that they do not cause any “back-drafting.” The system uses minimal electricity and should not noticeably affect heating and cooling efficiency.

Sub-Slab Depressurization System
Figure courtesy NYSDOH, October 2006

What happens after the samples have been collected?
After samples have been collected and analyzed in a laboratory, DEQ will provide property owners with the sample results and an explanation of the data. If sample results indicate that vapor intrusion may be occurring, DEQ may require additional testing or the installation of mitigation systems, in addition to requiring cleanup of the subsurface sources.

 

 

WATER

 

Does DEQ/SRS have guidelines for low-flow sampling?
Yes, please refer to the SRS Low-flow Purging and Sampling Guidelines Memo.

When conducting groundwater sampling, how may I dispose of purge water?
In most circumstances, groundwater purge water may be disposed of per the flowchart located here: SRS Purge Water Disposal Flowchart.

What are the requirements for installing, surveying, and abandoning monitoring wells?

The Montana Department of Natural Resources and Conservation (DNRC) has adopted rules governing the installation and abandonment of monitoring wells in Montana.  Construction standards for monitoring wells are found in Administrative Rule of Montana (ARM) 36.21.801 et seq. and includes requirements for construction materials, installation of seals, prevention of contamination by equipment, and site protection and security.  The regulations also require that a monitoring well constructor licensed by the Montana Board of Water Well Contractors prepare a monitoring well report form for each monitoring well drilled. The monitoring well constructor must supply copies of the report to the monitoring well owner and DNRC within 60 days of completing the well and must also retain a copy as a record in the constructor's files.

In addition, Montana Code Annotated (MCA) § 85-2-516 requires that, within 60 days after any well is completed, the driller shall file a well log report with the Montana State Bureau of Mines and Geology.  The well log report must be filed on a form specified by DNRC, which includes identifying a location for the well using at least two methods as specified on the form.

An initial survey of groundwater monitoring well elevations must be completed by a licensed surveyor or professional engineer registered in the State of Montana in accordance with MCA § 37-67-301 et seq. and ARM 24.183.101 et seq.  Survey results must provide an accuracy of plus or minus 0.1 foot horizontally and plus or minus 0.01 foot vertically.  The vertical control datum used to determine the elevation of the well must be the North American Vertical Datum of 1988 (NAVD 88), which should be referenced to a nearby United States Geological Survey (USGS), or equivalent, benchmark.

The Montana Department of Environmental Quality (DEQ) standard for determining latitude and longitude coordinates is the State Plane NAD83 HARN Coordinate System, which should also be referenced to a nearby USGS, or equivalent, horizontal control mark.

ARM 36.21.810 provides that “[w]ells which have not been monitored for more than 3 years shall be deemed abandoned unless written permission is obtained from the board [of water well contractors] to maintain the well.”  Standards for abandoning monitoring wells is also provided in this regulation.

Additional regulation regarding Monitoring Well Construction Standards can be found in the ARM 36.21.8.

Can I do a risk assessment to close a site when the site has an exceedance of Montana numeric water quality (DEQ-7) standards?
No. DEQ-7 standards were developed to comply with requirements under the Montana Water Quality Act, the Federal Clean Water Act, and the Montana Agricultural Chemical Ground Water Protection Act and must be used. A risk assessment that provides site-specific cleanup levels may be appropriate for contaminants in soil, but not in groundwater.

What kinds of site-specific data do I need before I can calculate site-specific cleanup levels protective of groundwater or perform other kinds of modeling at a site?
Please refer to the DEQ guidance document "Field Data Needs for Fate and Transport Modeling."

Do I have to sample for both total and dissolved metals in groundwater?
DEQ/SRS will generally not require that groundwater samples taken from monitoring wells be analyzed for total metals but will continue to require that drinking water wells be analyzed for total metals. DEQ/SRS may require total metals analysis of groundwater from monitoring wells on a case-by-case basis, as necessitated by special situations (i.e. analyzing background monitoring wells for comparison to drinking water wells). Samples taken from monitoring wells must still meet compliance with other water quality requirements including Montana’s Numeric Water Quality Standards (DEQ-7).

 

 

SAMPLING

 

What are the initial screening levels used for determining contaminants of concern?

DEQ has determined that an imminent and substantial endangerment to public health, safety, or welfare or the environment may exist if contaminant concentrations exceed certain risk-based screening levels.  Contaminants of concern (COCs) are those contaminants whose concentrations exceed these risk-based screening levels, and therefore require additional evaluation.  Contaminants whose concentrations fall below these screening levels will not typically trigger CECRA action.

The various screening levels listed below are separated out by media:

Groundwater/Drinking water/Surface water:
Soils and Sediments:

  • Sediment concentrations will be compared to EPA Region 3 BTAG Freshwater Sediment Screening Benchmarks.

  • Except for arsenic in surface soil, dry-weight soil concentrations will be compared to the direct contact and leaching to groundwater-based soil screening levels (SSLs) contained in the most recent Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites guidance document.  The RSLs take into account ingestion, inhalation, and dermal contact pathways and include residential and industrial exposure.  Additionally, DEQ compares petroleum compounds in soil to the Risk-Based Screening Levels (RBSLs) provided in the Montana Tier 1 Risk-Based Corrective Action Guidance for Petroleum Releases. After comparing contaminant concentrations in soil to the various screening levels, the most conservative value should be chosen as the applicable screening level.

    • Please note that the SSLs found in the EPA RSL table are based upon MCLs.  If the DEQ-7 groundwater standard is more conservative than the MCL, the SSL must be recalculated so that it is based upon DEQ-7 groundwater standards and multiplied by a dilution attenuation factor of 10, the state-specific attenuation factor.  Please see the flow chart of the soil screening process for additional information on how to calculate the SSL based upon DEQ-7 standards.
    • Please also note that the non-carcinogenic contaminants screening levels found in EPA RSL table are based upon a hazard index of 1 (a level which indicates that no adverse non-cancer human health effects are expected to occur for that contaminant).  When screening contaminant concentrations to the RSLs, with the exception of lead, adjust all non-carcinogenic levels by dividing by ten. This ensures that, when multiple contaminants are found at a facility that may have the same health effects, cumulative potential health effects are considered.  Please see the flow chart of the soil screening process for additional information on how DEQ screens all non-carcinogens (except lead) by dividing the RSL screening levels by ten.
    • Exposure to lead in soils is evaluated in a unique way by calculating potential blood lead levels resulting from exposure to lead in soil in addition to other unavoidable lead exposure pathways like water and food. Therefore, DEQ does not include exposure to lead with the other cumulative non-carcinogenic effects. DEQ uses the EPA RSLs of 400 mg/kg for lead in residential soils and 800 mg/kg for lead in industrial soils.
    • When screening arsenic concentrations in surface soil, compare contaminant concentrations to DEQ Remediation Division, Action Level for Arsenic in Surface Soil (April 2005).
Indoor Air/Soil Vapor:
  • Indoor air and soil vapor concentrations are compared to the residential air and industrial air screening levels contained in the most recent Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites guidance document.

    • Please note that the non-carcinogenic contaminants screening levels found in EPA RSL table are based upon a hazard index of 1 (a level which indicates that no adverse non-cancer human health effects are expected to occur for that contaminant).  When screening contaminant concentrations to the regional screening levels, with the exception of lead, adjusts all non-carcinogenic levels by dividing by ten. This ensures cumulative potential health effects are considered when multiple contaminants with the same health effects are present at a facility.

    • Please also note that DEQ developed generic screening levels for the petroleum fractions detected using the Massachusetts Air-Phase Petroleum Hydrocarbons (APH) method but not found in the RSL table.  DEQ calculated these screening levels using the same assumptions as those EPA used to calculate the RSLs.  As these petroleum fractions are non-carcinogens,  DEQ adjusted the target hazard index by dividing by ten to ensure that cumulative potential health effects are addressed (please see previous bullet).  The adjusted APH generic screening levels are:

Generic APH Fraction Screening Levels
APH Fraction Screening Level (ug/m3)
Aliphatic (C5-C8) 73.0
Aliphatic (C9-C12) 20.9
Aromatic (C9-C10) 5.2

 

What are the cleanup levels that should be used?

  • Established generic screening levels: For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance. For appropriate current and proposed facility-specific recreational use at remote mining facilities, DEQ may accept the cleanup levels established by DEQ’s Risk-Based Cleanup Guidelines for Abandoned Mine Sites (DEQ 1996). However, the recreational use must match that provided in Risk-Based Cleanup Guidelines document and transport of contaminants from soil to groundwater must be evaluated.
  • Background cleanup levels: DEQ accepts attainment of facility-specific background levels based on samples collected from unimpacted areas representative of conditions at the facility for compounds such as metals. Established literature values for background concentrations may be also be proposed. In some cases, background concentrations may exceed screening levels and may, therefore, be used in place of screening levels. However, background concentrations that exceed ERCLs may necessitate that a facility remain on the CECRA Priority List regardless of the status of a VCP.
  • Facility-specific adjusted screening levels: The generic screening levels described above may be adjusted based on the number of compounds present at an individual facility to represent the DEQ-accepted cumulative cancer risk of less than or equal to 1X10-5 for carcinogens or by the number of compounds and their critical effect/target organs for a total hazard index equal to 1 for non-carcinogens. For example, in the RSL table, RSLs for carcinogenic compounds are based on a 1x10-6 cumulative risk, while DEQ will accept a cumulative risk of 1x10-5. The RSLs for non-carcinogenic compounds can be adjusted in a similar manner to account for multiple compounds that have the same critical effect or target organ.
  • Facility-specific risk-based cleanup levels: The applicant can propose cleanup levels based on a facility-specific risk analysis conducted using standard EPA human health risk assessment guidance (EPA 1999, 1998a, 1997b, 1992, 1991a-c, and 1989) and/or, as applicable, standard EPA ecological risk assessment guidance (EPA 2000a, 1998b, and 1997a). For human health DEQ allows cleanup levels calculated based on cumulative risk levels less than or equal to a total excess cancer risk of 1x10-5 for carcinogens or a total hazard index less than or equal to 1 for non-carcinogens. Ecological risks must also be evaluated and acceptable risk determinations are made on a facility-specific basis. All exposure assumptions must be acceptable to DEQ and are best determined in consultation with DEQ. 

What must be included with laboratory analytical sample results reports?
The following items are typically included in a Level III analytical package (depending on the laboratory) and must be included with laboratory analytical results submitted to DEQ:

  • Results Summary Report Including Surrogate Recovery Data;
  • Results for soil and sediment samples reported on a dry-weight basis;
  • Chromatograms (if applicable);
  • Continuing Calibration Verification Reports;
  • Laboratory Control Sample Reports (if applicable);
  • Laboratory Method Blank Reports;
  • Laboratory Fortified Blank Reports;
  • Duplicate Analysis or Matrix Spike/Matrix Spike Duplicate analysis reports;
  • Field, trip, and rinsate blank reports (if applicable);
  • Sample ID cross-reference (if applicable);
  • Chain of Custody Form(s); and
  • Sample Receipt Checklist.

What is an acceptable grid size for confirmation sampling?
DEQ typically requires that confirmation sampling grids be 25 feet by 25 feet. However, alternate sampling strategies are considered on a facility-specific basis. For example, it may be appropriate to collect samples along radial lines extending from a known source of airborne contamination. It may also be appropriate to collect samples from larger grids on very large facilities; however, factors like heterogeneity of contamination must be considered in determining grid size. It is also important to balance analytical costs with the cost of remediating larger grids that do not meet cleanup levels.

How do I demonstrate that backfill is clean?
Backfill material to be used on a site needs to be adequately characterized to demonstrate that the backfill material does not contain contaminants at concentrations greater than established cleanup levels. DEQ must approve all proposed backfill and borrow source material before it can be used. Collect samples from all proposed backfill material and analyze for the eight Resource Conservation Recovery Act (RCRA) metals (i.e, arsenic, barium, cadmium, chromium, lead, selenium, silver, and mercury). Research DEQ’s electronic databases for known contaminated sites to determine if the proposed backfill source is in the database or is adjacent to a site listed in the database. If the proposed backfill source is in the database or is adjacent to a site listed in the database, additional analysis may be required for parameter(s) known to be present at the listed site. See the Montana DEQ Digital Atlas/Online Query Service to search for sites in DEQ’s database.

Generally, at least one 5-point composite sample needs to be collected for every 400 cubic yards of backfill material. If large volumes of backfill material are needed, you may propose an alternative sample frequency.

Why do I have to sample for dioxins when pentachlorophenol contamination is the problem?
Dioxins and furans are created as a by-product during the manufacturing of pentachlorophenol, among other things, and are always present where pentachlorophenol is found. Both dioxins/furans and pentachlorophenol are considered probable human carcinogens, although dioxins/furans are more carcinogenic at much lower concentrations. For example, pentachlorophenol is generally measured in parts per billion, while dioxins/furans are measured in parts per quadrillion. Therefore, DEQ/SRS requires that samples be analyzed for dioxins/furans using EPA Method 8290 at all sites where pentachlorophenol is suspected or found to be present.

What are TEQs and why/how do I calculate them for dioxins/furans?
Because dioxins/furans are actually a combination of many different chemical compounds, a toxicity equivalence quotient (TEQ) is calculated to represent the total toxicity for each sample. This TEQ concentration is calculated by adjusting the concentrations of several of the dioxin/furan compounds to account for their toxicity and then adding all of the adjusted concentrations. This totaled concentration (identified as a Total TEQ) is then compared to the appropriate screening level. DEQ has developed a TEQ Dioxins/Furans Calculator for Soil and Water Samples to assist in the calculation of TEQs.

How do I calculate a TEQ for dioxins/furans when the lab qualifies a congener as a “K” or EMPC?
A “K” or estimated maximum possible concentration (EMPC) qualifier from the lab means that interfering substances impacted the determination of which compounds were present in the sample. Therefore, the laboratory must estimate the maximum possible detection of the compound. In the TEQ calculator “K” or EMPC values are treated as the detection limit (DL) and therefore these values should be included in the DL column.

What happens if there is no analytical method with a low enough detection limit to tell if a sample meets a given standard?
If there is no analytical method with a low enough detection limit to determine if the sample meets a given standard or screening level, then DEQ/SRS generally requires that the sample be analyzed using the lowest available detection limit.  For surface and ground water samples, the analytical method must achieve the required reporting limit included in the most current version of Circular DEQ-7.  For soil, sediment, and air samples, the analytical method must achieve the lowest available reporting limits.  If the reporting limit is higher than the soil screening level for leaching to groundwater, DEQ may require groundwater sampling or additional soil sampling or both to confirm that the compound is not leaching.  For metals and dioxins/furans in water or soil and for some compounds in indoor or outdoor air, DEQ may recommend a comparison to background concentrations.

What if I’ve used an analytical method that doesn’t have a low enough detection limit, but there are other methods available that have lower detection limits?
With all of the different analytical methods that exist today, it is hard to determine which one may be the best. As a general rule, it is recommended that the method with the lowest detection limit be used, especially if you intend to seek closure of the site. If you have previous samples that were analyzed using an analytical method that has a higher detection limit, DEQ/SRS will generally require that you collect some additional confirmation samples and have them analyzed using the method with the lowest possible detection limit to show that the contamination has been cleaned up or does not exist before a closure letter can be issued.

When is sampling of free product and groundwater beneath free product appropriate?
While not required at all facilities, DEQ may require sampling of free product and groundwater beneath free product under certain site-specific circumstances as sampling of free product and groundwater beneath free product can provide useful information. DEQ may require this sampling to: assist in development of a more complete site conceptual model; determine the nature and extent of contamination at a facility; identify chemical composition in free product and dissolved-phase contamination; assist in development of site clean-up methods; and assist in identifying natural attenuation factors, among other things. This sampling may also be appropriate during initial investigations, if the history of the facility is unknown or uncertain or if there are neighboring properties that have used potential contaminants (e.g. industrial sites or gas stations) that may result in multiple contaminant sources.

Collection of groundwater samples beneath free product should be planned carefully, as passing sampling instruments through free product may contaminate the equipment. Sampling intervals and the associated sampling equipment and procedures for collecting a groundwater sample separate from free product should be identified in the sampling plan for DEQ approval. When conducting this sampling, it is important to use experienced field personnel to ensure valid sampling results.

 

 

RISK ASSESSMENT/ANALYSIS

 

What is "excess lifetime cancer risk?"
Long-term exposure to any concentration of a cancer-causing compound is assumed to have some risk, so when determining site-specific cleanup levels, DEQ must choose concentrations that are very protective. The term “excess lifetime cancer risk” is used because all people have a risk of getting cancer due to genetics or other causes not related to a DEQ-regulated Facility. According to the SEER Cancer Statistics Review, American men have a 44% lifetime risk of being diagnosed with cancer, while American women have a 38% lifetime risk (National Cancer Institute, 2009). This is a little over a 1 in 3 chance (or 33% or 0.33) that a person will get some type of cancer at some time in his or her life. "Excess lifetime cancer risk” is additional risk that someone might have of getting cancer if that person is exposed to cancer-causing compounds. DEQ considers an additional or excess 1 in 100,000 chance (or 0.001% or 0.00001 or 1 x 10-5) allowable. (The Montana Legislature has directed that 1 x 10-5 is an allowable risk for state water, § 75-5-301, MCA, and based on that level, DEQ has determined that 1 x 10-5 is an appropriate risk). DEQ derives site-specific cleanup levels such that they do not result in a cumulative excess lifetime cancer risk greater than 1 in 100,000.

Does the state have its own Risk Assessment/Analysis (RA) guidance?
No.  Following is a partial list of guidance documents for risk assessment/analysis. (Please note that some of these references may contain outdated information.)

  • Revised Policy on Performance of Risk Assessment During Remedial Investigation/Feasibility Studies (RI/FS) Conducted by Potential Responsible Parties (Environmental Protection Agency, Washington, DC. Office of Emergency and Remedial Response - EPA 540-F-99-025; OSWER-9340.1-02, January 1996)
  • Risk Assessment Guidance for Superfund (RAGS) Volume 1 - Parts A through D (Environmental Protection Agency, Washington, DC. - EPA/540/1-89/002, December 1989; EPA 540/R-92/003, December 1991; Publication 9285.7-01C, October 1991; and, Publication 9285.7-47; December 2001)
  • Risk Assessment Guidance for Superfund (RAGS) Volume 1 - Part E (Environmental Protection Agency, Washington, DC. - EPA/540/R/99/005, July 2004)
  • Human Health Toxicity Values in Superfund Risk Assessments (Environmental Protection Agency, Washington, DC. - OSWER 9825.7-53, December 2003)
  • Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites (Environmental Protection Agency, Washington, D.C. - OSWER 9825.6-10, December 2002)
  • Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments (Environmental Protection Agency, Washington, DC. - EPA 540/R/97/006, OSWER 9285.7-25; June 1997)
  • Exposure Factors Handbook: 2011 Edition - Environmental Protection Agency, Washington, DC, (EPA/600/R-09/052F)

Below are some general assumptions which should be considered when conducting risk assessment/analysis.

What do we consider allowable risks (i.e. cumulative 1x10-5 and HI of 1)?For human health, DEQ allows cleanup levels calculated based on cumulative risk levels less than or equal to a total excess cancer risk of 1x10-5 for carcinogens or a total hazard index less than or equal to 1 for non-carcinogens. Ecological risks must also be evaluated and acceptable risk determinations are made on a facility-specific basis. All exposure assumptions must be acceptable to DEQ and are best determined in consultation with DEQ.

What are some of the general assumptions for a site-specific soil risk assessment/analysis at an SRS site?

General Information:

  • For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance.
  • Cumulative cancer risk for carcinogenic compounds may not exceed 1 X 10-5.
  • Total hazard index for non-carcinogenic compounds may not exceed 1 for each target organ.
  • Include an evaluation of ingestion, dermal, and inhalation exposure.
  • For inhalation exposure, include both particulate and vapor inhalation for volatile compounds.
  • For guidance on addressing dermal factors, refer to EPA’s Risk Assessment Guidance for Superfund (RAGs) Part E.
  • For guidance on inhalation risk, refer to Appendix D of the U.S. Environmental Protection Agency’s (EPA) Region/ORD Workshop on Inhalation Risk Assessment: A Superfund Focus Summary Report available online at http://www.epa.gov/oswer/riskassessment/pdf/
    finalinhalationriskworkshop.pdf    . EPA plans to release RAGs Part F soon, which addresses inhalation risk, at which point it will be available as guidance for inhalation risk.
  • For the hierarchy of human health toxicity, refer to OSWER Directive 9285.7-53, EPA’s 12/5/03 Memorandum regarding Human Health Toxicity Values in Superfund Risk Assessments.
  • For assistance with risk assessment/analysis for petroleum compounds, click here to see the Tier 1 Risk-Based Corrective Action Guidance for Petroleum Releases (dated September 2009) Appendix E spreadsheets.
  • For some contaminants in residential soils, it may be appropriate to consider ingestion of produce and/or breast milk. Please discuss these issues with DEQ to determine whether a quantitative evaluation is necessary.
  • Agricultural, ecological, recreational, and/or other exposure scenarios can exist (although not covered below) and will be evaluated on a site-specific basis.
  • When developing site-specific cleanup levels, the soil leaching to groundwater pathway must be considered to ensure protection of groundwater. For guidance on calculating cleanup levels for this pathway, please refer to the Fate and Transport FAQ.
  • For more information on how to evaluate vapor intrusion to indoor air, please see the FAQ for site-specific vapor intrusion risk assessment/analysis.

Update - Specific Exposure Scenarios have recently been updated per the 2011 Exposure Facility Handbook: While each facility is different based on its site-specific conditions, the following typical assumptions have been used and approved by DEQ.

Residential exposure scenario:

  • Carcinogenic compounds:
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 270 days per year (Assumes 3 months of snow cover/frozen ground and a 2 week vacation)
    • Exposure duration: 30 years
    • Averaging time: 28,470 days (365 days x 78 years)
    • Soil ingestion rate: Age adjusted: 95 milligrams (mg) soil per day (Age-adjusted soil ingestion rate is based on the equation provided in the EPA Regional Screening Levels for Chemical Contaminants at Superfund Sites document, which utilizes both the adult soil ingestion rate (50 mg soil per day), and the child soil ingestion rate (200 mg soil per day) and adjusts them for body weight and exposure duration)
  • Non-carcinogenic compounds:
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 270 days per year (Assumes 3 months of snow cover/frozen ground and a 2 week vacation)
    • Exposure duration: 6 years
    • Averaging time: 2,190 days (365 days x 6 years)
    • Soil ingestion rate: Child - 200 milligrams (mg) soil per day
    • Body Weight: Child - 15 kilograms

Commercial/industrial exposure scenario:

  • Carcinogenic compounds:
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 187 days per year (Assumes a standard 5-day work week, 3 months of snow cover/frozen ground, and a 2 week vacation)
    • Exposure duration: 25 years
    • Averaging time: 28,470 days (365 days x 78 years)
    • Soil Ingestion rate: Adult: 50 mg soil per day
  • Non-carcinogenic compounds:
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 187 days (Assumes a standard 5-day work week, 3 months of snow cover/frozen ground, and a 2 week vacation)
    • Exposure duration: 25 years
    • Averaging time: 9,125 days (365 days x 25 years)
    • Soil ingestion rate: Adult: 50 mg soil per day

Excavation exposure scenario:

  • Carcinogenic compounds:
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 124 days per year (Professional judgment based on assumption of 4 months of open excavation)
    • Exposure duration: 1 year
    • Averaging time: 28,470 days (365 days x 78 years)
    • Soil ingestion rate: Adult: 330 mg soil per day
  • Non-carcinogenic compounds:
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 124 days per year (Professional judgment based on assumption of 4 months of open excavation)
    • Exposure duration: 1 year
    • Averaging time: 365 days (365 days x 1 year)
    • Soil ingestion rate: Adult: 330 mg soil per day

Trespasser exposure scenario:

  • Carcinogenic compounds:
    • Assume adolescent (6-18 years old - 45 kilogram bodyweight) is trespasser
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 75 days per year (Professional judgment based on assumption of 2 days per week and 3 months of snow cover/frozen ground)
    • Exposure duration: 13 years
    • Averaging time: 28,470 days (365 days x 78 years)
    • Soil ingestion rate: Adult: 100 mg soil per day
  • Non-carcinogenic compounds:
    • Assume adolescent (6-18 years old - 45 kilogram bodyweight) is trespasser
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 75 days per year (Professional judgment based on assumption of 2 days per week and 3 months of snow cover/frozen ground)
    • Exposure duration: 13 years
    • Averaging time: 4,745 days (365 days x 13 years)
    • Soil ingestion rate: Adult: 100 mg soil per day

What are some of the general assumptions for a site-specific groundwater risk assessment/analysis at an SRS site?

General information:

  • For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance.
  • For compounds that have them, the Montana numeric water quality (DEQ-7) standards are the cleanup levels, and performance of a risk assessment/analysis for groundwater is not necessary. The DEQ-7 standards are equal to or are more protective than the EPA Safe Drinking Water Standards.
  • For compounds that do not have DEQ-7 standards, risk-based screening levels (RBSLs) from the Montana Tier 1 Risk-Based Corrective Action Guidance for Petroleum Releases (RBCA) document may be used as cleanup levels or site-specific cleanup levels may be calculated.
  • For compounds that do not have DEQ-7 standards or RBSLs, it may be possible to use the tapwater regional screening levels (RSLs) provided in the most recent Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites. Please note that the RSLs for carcinogenic compounds are based on a 1x10-6 cumulative risk, while the DEQ-7 standards are based on a 1x10-5 cumulative risk. Therefore, it may be possible to calculate a different RSL based on a 1x10-5 cumulative risk.
  • Cleanup levels based on drinking water are typically protective of construction workers encountering groundwater, and therefore it is not usually necessary to evaluate construction worker exposure to groundwater quantitatively. If it is necessary to evaluate construction worker exposure to groundwater, the exposure assumptions used for construction worker exposure to soil are also applicable to this exposure scenario.
  • For more information on how to evaluate vapor intrusion to indoor air, please see the FAQ for vapor intrusion risk assessment/analysis.

What are some of the general assumptions for a site-specific surface water and sediment risk assessment/analysis at an SRS site?

General Information: For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance.

Surface Water:

  • Like groundwater, Montana’s numeric water quality (DEQ-7) standards are used as the cleanup levels. Both the DEQ-7 standards for human health and aquatic life (acute and chronic) must be considered, and the most protective of the numbers must be used as the cleanup level.
  • If there is not a DEQ-7 standard available for a compound, a site-specific risk assessment/analysis may be necessary. DEQ does not have generic assumptions for surface water risk assessment/analysis other than those used in calculating the EPA tap water (representing drinking water) Regional Screening Levels (RSL) for Chemical Contaminants at Superfund Sites.
  • Ecological exposure usually drives surface water cleanup.

Sediment:

  • Sediment is evaluated on a site-specific basis and DEQ does not have generic assumptions.

What are some of the general assumptions for a site-specific vapor intrusion risk assessment/analysis at an SRS site?

General Information:

  • For initial screening of contaminants of concern, please refer to the Screening FAQs for guidance.
  • If volatile compounds are contaminants of concern at a facility:
    • Evaluate indoor air (inside habitable structure) and sub-slab (underneath the building foundation/basement) conditions to determine if sampling is necessary.
    • If no buildings exist at the facility, soil gas sampling will likely be necessary and institutional controls may be necessary to limit future exposure.
  • DEQ will consider alternative assumptions on a site-specific basis.
  • Exposure to outdoor vapors is addressed under the FAQ regarding general assumptions for a site-specific soil risk assessment/analysis.

Specific Scenarios: While each facility is different based on its site-specific conditions, the following typical assumptions have been used and approved by DEQ.

Residential exposure scenario:

  • Carcinogenic compounds:
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 350 days per year (Assumes a 2 week vacation)
    • Exposure duration: 30 years
    • Averaging time: 28,470 days (365 days x 78 years)
    • Exposure time: 24 hours per day
  • Non-carcinogenic compounds:
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 350 days per year (Assumes a 2 week vacation)
    • Exposure duration: 30 years
    • Averaging time: 10,950 days (365 days x 30 years)
    • Exposure time: 24 hours per day

For a worker exposure scenario:

  • Carcinogenic compounds:
    • Target risk: Divide cumulative cancer risk by number of carcinogenic compounds
    • Exposure frequency: 250 days per year (Assumes a standard 5-day work week and a 2 week vacation)
    • Exposure duration: 25 years
    • Averaging time: 28,470 days (365 days x 78 years)
    • Exposure time: 8 hours/24 hours
  • Non-carcinogenic compounds:
    • Target hazard quotient: Hazard index divided by number of compounds with the same critical effect
    • Exposure frequency: 250 days (Assumes a standard 5-day work week and a 2 week vacation)
    • Exposure duration: 25 years
    • Averaging time: 9,125 days (365 days x 25 years)
    • Exposure time: 8 hours/24 hours

How does DEQ calculate reasonable maximum exposure point concentrations?

DEQ uses EPA's most current version of ProUCL to calculate reasonable maximum exposure point concentrations (RMEPCs). Please note that ProUCL provides the means for calculating RMEPCs for data sets that include non-detects. When ProUCL calculates a RMEPC, it will recommend that an upper confidence limit (UCL) of 95% or greater is the best fit for the data presented (e.g. 97.5% or 99% UCL). DEQ typically requires that the UCL recommended by ProUCL which best fits the data presented be used as the RMEPC. Please note that depending on a specific data set, it may not be appropriate to perform a UCL calculation. This is particularly true for very small data sets or for data sets with less than 5 detections. DEQ will evaluate the ProUCL output including any warnings or recommendations to these must be submitted for review. If you have any questions please contact the project officer for the facility. The ProUCL software can be downloaded free from EPA's website at the following link: http://www.epa.gov/esd/tsc/software.htm

How should non-detects be used in risk assessment? 

DEQ recommends the use of the ProUCL software available through EPA’s website at http://www.epa.gov/esd/tsc/software.htm for statistical analysis of data used for risk assessment purposes.  The ProUCL software provides statistical analysis of non-detects or censored data; therefore, there is no need to use half the detection limit for undetected compounds (with the exception of calculations of toxicity equivalence quotients for dioxins/furans or other dioxin-like compounds - please refer to the FAQ regarding sampling for dioxins/furans for more information). The ProUCL software also provides information regarding whether there is enough data available for statistical analysis, whether the data set falls into a particular distribution, whether an upper confidence limit (UCL) other than 95% (i.e., 97%, 99%) is appropriate given the data set; and also provides a limited outlier analysis. It is generally appropriate to follow the ProUCL recommendations. Thorough justification and DEQ approval is required for proposals that do not follow these recommendations.

 

 

BROWNFIELDS

 

How do I apply for Brownfields funding and what can it be used for?
There are three different mechanisms from which you can apply for brownfields funding:

  1. Montana Targeted Brownfields Assessments: A Montana targeted brownfields assessment means that DEQ will hire one of its contractors to conduct an assessment of the property in question. An assessment may include a phase I assessment, phase II assessment and/or an establishment of cleanup options. Currently, DEQ will only consider targeted brownfields assessments for sites it is already working on. The application to apply for a targeted brownfields assessment can be obtained on DEQ’s brownfields website at: http://deq.mt.gov/Brownfields/default.mcpx.
  2. Environmental Protection Agency (EPA) Targeted Brownfields Assessments: An EPA targeted brownfields assessment means that EPA will hire one of its contractors to conduct an assessment of the property in question. An assessment may include a phase I assessment, phase II assessment and/or an establishment of cleanup options. The application to apply for an EPA targeted brownfields assessment can be obtained on EPA’s brownfields website at: http://www.epa.gov/region08/land_waste/bfhome/bftba.html.
  3. EPA competitive grants: Each year EPA solicits grant applications for assessment, cleanup, revolving loan funds and job training. EPA reviews these grant applications on a national basis and typically awards around $100 million each year. Assessment funding can be used for assessments and the establishment of cleanup options. Cleanup money can be used for actual cleanup of a site. A revolving loan fund can be used to give grants and low-interest loans out for cleanup at sites. Job training grants can be used to provide folks with training regarding different environmental aspects. To find out when the next grant application process begins and to learn how to apply, go to EPA’s brownfields website at: http://www.epa.gov/brownfields.

What are the requirements to apply for brownfields funding through EPA and DEQ?
To apply for any brownfields grant, you must be a governmental entity, tribe, or certified regional development corporation. In addition, other criteria that must be met are:

  1. Must be a clear benefit to the community
  2. Applicant must not have contributed to the contamination
  3. Assistance is crucial to the redevelopment or reuse of the site

Also, if the site is contaminated with petroleum products, the site must:

  1. be of “relatively low-risk” compared to other petroleum-contaminated sites in the state
  2. have “no viable responsible party”
  3. be assessed, investigated, or cleaned up by a person not potentially liable for the contamination
  4. not be subject to a corrective action order under Resource Conservation and Recovery Act
  5. not be a LUST/TRUST fund site

 

GET MORE INFORMATION

 

How do I get copies of documents in a facility file?
Please contact DEQ/SRS at (406) 841-5000 to make arrangements for viewing and/or copying facility files.  Click here to view site file guides.

How do I access SRS database information online?
Follow the instructions located at:  http://www.deq.mt.gov/rem/InteractiveMaps.mcpx.