Updated Map Tracks PFAS Contamination in the U.S.


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On May 6, 2019, the Environmental Working Group and the Social Science Environmental Health Research Institute at Northeastern University released the latest update of their interactive map  documenting the publicly known contamination from PFAS chemicals in the United States.   At least 610 locations, including public water systems, military bases, military and civilian airports, industrial plants, dumps, and firefighter training sites, are known to be contaminated.  The map is color coded to distinguish between PFAS contamination at military sites, in drinking water and at other known sites.  The user can navigate to areas of interest and click the site icon and a window pops up with the available information, including the site name, location, the PFOS/PFOA concentration range, and the suspected PFAS source. 

Michigan leads the country with 192 locations, which is 145 more than California, the state with the second most sites (47).  The numbers for Michigan, however, are likely skewed because of their ongoing, comprehensive PFAS testing program.  Beginning in April 2018, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) launched a statewide sampling program to test Michigan’s public water supplies.  In February 2019, ENGL announced that 1,114 public water systems, 461 school wells and 17 tribal water systems had been tested.  In addition to the public water systems, municipal waste-water treatment plants, permitted NPDES dischargers and industrial facilities, military bases and landfills known to have used or disposed of PFAS containing materials had been targeted for sampling.  Imagine what the national map might look like if every state had a PFAS sampling program like Michigan. 

Published in Cox-Colvin’s May 2019 Focus on the Environment newsletter.

There are, or have been, thousands of small commercial dry cleaning operations throughout the U.S. – nearly every neighborhood had one. Most of them are, or were, small family owned businesses that started in the 30s, 40s, or 50s.  Many of these facilities became ‘anchor’ stores of small shopping centers that are now being redeveloped.  The first step in the redevelopment process should be the Phase I Environmental Site Assessment. However, many times this essential first step is requested after the deals are well along their way.  As an environmental professional, we find ourselves fielding calls that begin with “We’re closing next week, and need a Phase I done.”  What could go wrong?

In this series of articles, we will examine the pitfalls of real estate transactions involving former dry cleaner operations.  The first step in the process should be the Phase I Environmental Site Assessment (ESA), conducted by a qualified environmental professional.  The Phase I ESA is a desktop evaluation and site inspection that provides the prospective new buyer with information concerning past environmental concerns at a property generally known as “recognized environmental conditions” (RECs).

A standard step in the Phase I ESA is a review of environmental databases conducted through a third party service.  These databases searches, which are typically completed within a day, are very informative, and generally reveal if the property was once occupied by a former dry cleaning operation.  If a former dry cleaning operation is identified, this is the first clue that a REC is present on the property and that further actions should be taken (e.g., Phase II ESA) to evaluate the REC more closely. If there is an impending deadline approaching, this database search report may be the only tool relied upon to form a decision about the property; however, this is only the first clue that something may be up with this property. 

Other elements of the Phase I ESA should be reviewed very carefully as they may identify prior uses of the property that may not have been revealed in the database search alone.  The three most informative elements to review next are fire insurance maps, historical city directories and historical aerial photography. 

Fire insurance maps, where available, provide a great deal of detail about businesses that occupied the property in the past including the name and/or business activity, the shape of the buildings, as well as information concerning where products were stored and used.  Many times, these maps are more informative than aerial photography; however, if the property is not within a historically urban or industrial setting, their coverage may be limited.

City directories are important in that they provide the business name and more importantly the address of the operation.  If you have a former dry cleaning operation associated with your strip mall property, don’t be surprised to see the name and address change slightly through time.  For example, in 1956 – ABC Cleaners was located at 563 Maple Street; in 1975 – Atomic Cleaners was located at 571 Maple Street, then in 1995 – Super Dry Clean is located at 561 Maple Street.  During the site inspection the environmental professional located Super Dry Clean at 561 Maple Street.  Did people putting together the city directories make a mistake?  Probably not.  Aerial photography may help you clear this up.

A review of the aerial photography can help you sort out historical details because they provide photographic evidence of how the property was occupied at any given period of time.  In general, try to: 1) obtain enough photography to cover the range of years from pre-development to the present day; and 2) obtain photography with sufficient clarity to identify individual buildings with certainty.  In general, clarity is inversely related to the altitude of the flight line.  The higher the flight’s altitude, the lower the level of detail captured by the photography.  Obtaining the right photography can take some time and should be researched thoroughly.  Most third party database search firms provide aerials at an additional cost, but not all firms have access to good quality photography.    

In our example, there were no fire insurance maps available; however, it appears that the dry cleaner operation may have moved periodically based on the city directories.  Using the information from city directories while reviewing the aerial photography it was revealed that in 1950s, there was a single building resembling a house located at the location that would have had an address of 563 Maple Street (ABC Cleaners). By the 1970s, the location of that building, which been demolished, was now a parking lot for the current strip mall, whose range of addresses included 561 (Super Dry Clean) through 571 (Atomic Cleaners). The Phase I ESA has revealed not one, but three separate RECs associated with former dry cleaning operations.  These three RECs involve most of the property and could likely extend off-site.  The next step is to perform a Phase II ESA to better understand how these operations may have affected the property and the surrounding area.  Luckily for us, the prior owner conducted a Phase II ESA. 

Next month we will examine the Phase II ESA, what may have been missed, how it could affect your client, and how to plan for the future …the deal is heating up and the clock is ticking. 

Published in Cox-Colvin’s May 2019 Focus on the Environment newsletter.

The term PFAS refers to per-and polyfluoroalkyl substances, which comprise thousands of synthetic chemicals that have been used in a wide variety of consumer and industrial products since the 1940s.  PFAS is quickly becoming  the hottest topics in the environmental field  due in part  to numerous State-lead initiatives, work groups, and EPA’s February 14, 2019 PFAS Action Plan.  Two of the more commonly discussed PFAS, perfluorooctanoic acid (PFOA) and perfluoroctane sulfonate (PFOS), already have a 70 part per trillion (ppt) Health Advisory for drinking water and will be further evaluated by EPA to determine if a maximum contaminant level (MCL) is needed.  Several states have established their own MCLs and cleanup levels for various PFAS.  With these emerging contaminants headed toward increased regulation, questions regarding treatability are at the forefront.  This article is intended to provide a non-exhaustive elementary overview on PFAS treatability in environmental media by commonly employed technologies. 

PFAS have oil and water repellency, temperature resistance, friction reduction properties, and one of the strongest bonds in nature (fluoride-carbon).  These properties all contribute to PFAS resistance to treatment.  Most of the technologies that have demonstrated some level of  effectiveness are associated with ex-situ (i.e., above-ground) treatment of water contaminated with PFAS.  These technologies include activated carbon, reverse osmosis, and ion exchange.  However, the ability to achieve a desired removal rate or effluent concentration is highly site-specific and may not be scalable.  Additionally, these technologies all generate wastes that contain concentrated PFAS, which require management (likely by costly offsite thermal destruction).  While these resource- and energy-intensive “pump-and-treat” technologies are often associated with the treatment of other constituents in municipal drinking water systems, the remediation industry has generally moved away from pump-and-treat for more cost-effective and sustainable in-situ (i.e., in-ground) technologies.  If we are required to rely on these pump-and-treat technologies at commercial and industrial sites based purely on necessity, it would be a step backwards in the evolution of site remedies. 

The traditional approaches used for in-situ treatment of groundwater and soil have shown little promise for treatment of PFAS.  Like it’s ex-situ counterpart, activated carbon that is used in-situ does not on its own destroy contaminants, it merely transfer’s them from one media to another.  For this reason, activated carbon is often impregnated with other material to support contaminant destruction (e.g, zero valent iron).  However, the impregnated activated carbon products that are currently in commercial use have not been demonstrated to be effective on PFAS.  Therefore, if activated carbon (granular-, micro-, or nano-scale) were used in-situ, the result would be a concentrated mass of PFAS, which may require removal or replenishment of the activated carbon to ensure continued treatment.  Studies are ongoing to understand the long-term leachability of PFAS from various types of activated carbon and other forms of adsorbents.  It’s possible that with a change in subsurface geochemical conditions, including the introduction of other competing contaminants, PFAS could desorb from the treatment media and become remobilized.

To date, there does not appear to be  isolated bacterial strains that are capable of degrading PFAS.  Therefore, biotic natural attenuation, biostimulation, or bioaugmentation are not amendable treatment technologies for PFAS in soil and groundwater.  Some fungi strains may be capable of PFAS degradation; however, practical application to environmental media is a significant challenge.  The low volatility and high solubility of PFAS prohibits the use of air sparging and soil vapor extraction (in-situ) and air-stripping (ex-situ).  Various chemical oxidants are routinely used to treat contaminants in soil and groundwater.  However, studies suggest that there is either no or incomplete destruction of PFAS via chemical oxidation.  In a laboratory setting, when certain engineered conditions are present, specific types of oxidants may result in some degree of PFAS destruction.  However, practical scale-up to a natural system has yet to be successfully demonstrated.  To the best of my knowledge, excavation with landfill disposal or thermal destruction has been the only full-scale commercial technology to address PFAS in soil.  The pump-and-treat technologies previously identified show promise but have yet to be employed commercially for the intended purpose of treating PFAS.        

A complicating factor related to treatment of PFAS, is the presence and role of “precursors.”  Precursors are included within the thousands of substances that comprise the overall PFAS families.  However, unlike many of the PFAS that are currently or may be regulated by EPA and State agencies, precursors are not regulated and can readily degrade/transform biotically and abiotically under aerobic and anerobic conditions.  The problem becomes that precursor degradation/transformation creates more recalcitrant PFAS, such as those within the same regulated chemical groups as PFOA and PFOS.  Although this process can occur naturally, an unintended consequence of some treatment technologies is creation of additional PFAS from precursors that are present. 

Government agencies, universities, work groups, and private companies are all diligently working to better understand PFAS.  Like most other contaminants, there will likely not  be a “silver bullet” for PFAS treatment.  But hopefully, there will be new technologies developed or modifications of existing technologies that can treat environmental media contaminated with PFAS in a cost effective and sustainable manner while achieving the extremely low cleanup standards.          

Published in Cox-Colvin’s May 2019 Focus on the Environment newsletter.

Ohio EPA is in the process of performing their scheduled 5-year review of the Voluntary Action Program (VAP) rules. The proposed rules are currently available for Interested Party Review, with comments due by close of business, May 29, 2019. The majority of changes are to clean up language and make them more readable, although there are other notable changes that emphasize the importance of complying with institutional controls at VAP properties.

The rule definitions have been updated to include central management entities and land uses. As the VAP program has matured over the last couple of decades, engineering and institutional controls have become commonplace to manage the cost of remediation versus cleanup to unrestricted standards. While the concept of different land uses and exposure scenarios is nothing new, moving their definitions into Rule 1 emphasizes the importance of understanding their nuances and ensuring appropriate mechanisms and entities are in place to prevent inadvertent violation of the restrictions. In the VAP, using a property for an unapproved use, such as hosting a daycare on a portion of an industrial property, can quickly lead to the voidance of a Covenant Not to Sue. Additional land uses are now included in the rule, and defined land uses now include:

  • Residential land use (single family homes, condominiums, etc.)
  • Restricted residential land use (typically used for multi-tenant facilities like apartment buildings)
  • Unrestricted residential land use (protective for any land use without restriction)
  • Commercial land use (retail facilities, offices, warehouses, etc.)
  • Commercial land use with high frequency child exposure (schools, daycares, etc.)
  • Industrial land use (factories, power plants, marine port facilities, railroad yards, etc.)
  • Recreational land use (parks, play fields, amphitheaters, wildlife areas, etc.)

Of the defined land uses, “commercial land use with high frequency child exposure” and “recreational land use” were not previously discussed in the rules. The former may allow more flexibility for commercial properties where daycares or schools may be built (such as strip malls), while the recreational land use will require a site-specific risk assessment but could promote development of ball fields and wildlife areas where child exposures tend to be infrequent and shorter in duration.

The definition of “imminent hazard” has been modified to specifically reference risk from volatilization of chemicals from environmental media into occupied structures at acute health levels. This is consistent with agency efforts over the last few years to identify and assess vapor intrusion threats related to trichloroethylene.

Included in the draft rules is an option for laboratories to receive VAP certification based upon their NELAP accreditation. This has the potential to simplify certification for laboratories, and reduce a potential lag time for updates to laboratory SOPs receiving VAP approval.

Rule language relative to Phase I assessments has been modified to be more similar to All Appropriate Inquiry and ASTM E1527 requirements, although the VAP Phase I process remains more extensive than a standard due-diligence assessment.

The VAP rules now include generic cleanup standards for sediment, in addition to soil, groundwater and air. This helps to simplify evaluation of risk to ecological receptors.

Additional chemicals of concern have been added for petroleum, including lead scavengers for gasoline used prior to 1996. This brings the VAP rules in line with the most recent Ohio UST (BUSTR) rule revisions.

If you are considering entering a property in the VAP, or looking for assistance in ensuring continued compliance of a property that has already gone through VAP, contact us. Cox-Colvin has extensive experience with brownfields and the VAP. We regularly work with clients who are considering purchase of VAP properties to define the impact and cost of use restrictions on their redevelopment plans.

On April 25, 2019, US EPA (EPA)  released, for public comment, draft recommendations for addressing  groundwater contaminated with perfluorooctanoic acid (PFOA) and/or perfluoroctane sulfonate (PFOS) under federal cleanup programs, including the Comprehensive Environmental Response Compensation and Liability Act (CERCLA or Superfund) and site-wide corrective action under the Resource Conservation and Recovery Act (RCRA).  Development and publication of per-and polyfluoroalkyl substances (PFAS) groundwater cleanup guidance was identified in EPA’s February 2019 PFAS Action Plan as a priority action item for EPA. 

Broadly, the draft guidance provides interim recommendations for screening levels, and preliminary remediation goals (PRGs) to inform final cleanup levels for PFOA and/or PFOS contaminated groundwater that is a current or potential current source of drinking water.  Screening levels are conservative, typically risk-based levels used for the process of identifying and defining areas, contaminants, and conditions at a particular site that may warrant further evaluation.  Under CERCLA, RCRA and other regulatory programs, at sites where contaminant concentrations are below appropriate risk-based screening levels, no further action or study is generally warranted.  PRGs are initial targets for cleanup, which may be adjusted on a site-specific basis as more information becomes available.   

The guidance is poorly written and is, at best, confusing.  It is important to pay particular attention to the “ands” and “ors” when discussing PFOA and/or PFOS, and this document is no exception. From my read of the draft guidance, the recommendations are as follows (I have added the underlined text as emphasis):

  • Site screening should be conducted using a screening level set to a Hazard Quotient of 0.1 for PFOA or PFOS individually, which is currently 40 ng/L or parts per trillion (ppt);
  • Use of the EPA 2016 PFOA and PFOS health advisory of 70 ppt for the (combined concentration) of PFOA and PFOS as the PRG for groundwater that is a current or potential source of drinking water and where no state or tribal MCL or other applicable or relevant and appropriate requirements (ARARs) exist.
  • In situations where groundwater is being used for drinking water, EPA expects that responsible parties will address levels of PFOA and/or PFOS (individually or combined) over 70 ppt.

Missing from draft guidance is a CERCLA removal action level.  The removal action level is the level at which EPA would step in to take action without waiting for a responsible party to be identified and action by the responsible party to be taken.  As it turns out, a removal action level of 400 ppt (individual or combined) was included in the initial draft of the guidance but was removed prior to publishing the April 25 version for public comment.  A redline version of the original document is included in the regulatory docket.  The addition of RCRA Corrective Action to the discussion of federal cleanup programs to which the guidance would be applicable also appears to have been a late addition or afterthought.  The wholesale removal of the action level discussion as well as EPA’s effort to shoehorn RCRA Corrective Action into what started out as a CERCLA guidance document is clearly part of the reason for the confusion, but since when has that been a viable excuse?   

Due to the lack of federal leadership on the subject, some states have promulgated state-specific groundwater cleanup and drinking water standards for the compounds.  For these states, the guidance is likely to be considered too little too late.   Other states have taken more of a wait and see approach.  These states are just now likely wondering if the wait was worthwhile.   The draft document is open for public comment until June 10, 2019.  Submit your comments, identified by Docket ID No. EPA-HQ-OLEM-2019-0229, at https://www.regulations.gov.

Published in Cox-Colvin’s May 2019 Focus on the Environment newsletter.

On February 26, 2019, Toledo Ohio voters approved a charter amendment giving Lake Erie its own Bill of Rights or LEBOR. The measure establishes rights within the City’s charter for the Lake Erie Ecosystem to “exist, flourish, and naturally evolve” as well as rights to self-government and a clean and healthy environment for Toledo and its citizens. The amendment, put forth by the Toledoans for Safe Water, would allow city residents to sue to protect the lake regardless of existing federal and state laws or permits in defense of the violations. 

This particular movement began back in August of 2014, with a massive harmful algal bloom of cyanobacteria within the Western Basin of Lake Erie.  The 2014 event forced the shutdown of the City’s potable water system and cost millions of dollars in lost revenue alone.  

Not unexpectedly, the day after the LEBOR passed, a lawsuit was filed stating that the amendment is unconstitutional and violates state laws. One can only imagine the legal debates and law school writing assignments this amendment will generate. Who knows…the fact that we are talking about the Lake Erie harmful algal bloom and its impact may have been the goal of the LEBOR all along?      

Published in Cox-Colvin’s April 2019 Focus on the Environment newsletter.

As discussed in another article in this newsletter, some states have established drinking water standards for per-and polyfluoroalkyl substances (PFAS), or they are in the process of doing so. The standards being adopted are low – in the nanograms per liter (ng/L) or parts-per-trillion (ppt) range – and require very low laboratory detection limits. The US EPA has a current drinking water advisory of 70 ppt for perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS). In a recent webinar for local leaders, the Michigan Department of Environmental Quality used the analogy that one ppt is the same as one drop in 20 Olympic swimming pools. The low laboratory detection limits and the ubiquitous nature of these compounds have real implications for conducting sampling and analyses of environmental media

A Very Brief Primer on the Use and Presence of PFAS Compounds

PFAS compounds are just about everywhere. They have been used for decades in many industries: electronics, aerospace/defense, building/construction, alternative energy, automotive, semiconductors, military, healthcare, personal care products (e.g. deodorant and makeup), food packaging (e.g. microwave popcorn bags), non-stick cookware, outdoor apparel/equipment (e.g. GORE TEX), pharmaceuticals, stain resistant carpeting and furniture, and in aqueous film forming foams (AFFFs) used for fire training and firefighting. They have both water and oil resistant qualities. They are persistent in the environment and they bioaccumulate in body proteins. PFAS compounds are present in lakes, rivers and oceans; in soil; in wastewater treatment plant effluent; in polar snow and ice; and in wildlife. A striking revelation is that these compounds are present in the blood and tissue of polar bears in some of the most remote areas in the world.  PFAS compounds are in our food, drinking water, and in our blood serum.

Groundwater Sample Collection Considerations

Because these compounds are ubiquitous and the laboratory detection limits utilized are so low, the potential for inadvertent cross contamination of environmental samples is great. Cross contamination during sampling may occur from sampling equipment (i.e., bailers, pumps, tubing, containers, spoons, gloves, filters, drilling equipment, passive samplers, and decontamination water), from the sampling staff themselves (for example, from makeup or deodorant), or from airborne sources in the vicinity of the sample collection points. As such, there are special considerations that must be taken when sampling for PFAS compounds. These include the following:

  • Sampling equipment, sample bottles, and caps cannot contain Teflon
  • Samples should not be filtered, as filters may contain PFAS compounds
  • Disposable (single use) polyethylene or silicone sampling equipment should be used
  • PFAS adsorb to glass, so glass sampling containers cannot be used; high density polyethylene or polypropylene containers should be used.
  • Secondary cross contamination may occur from several sources:
    • PPE
    • Clothing
    • Waterproof logbooks and notebook paper
    • Permanent markers
    • Post-its
    • Paper towels
    • Stain- and water-resistant clothing/boots
    • Insect repellents
    • Sunscreen, moisturizers, makeup
    • Blue ice
  • Well washed clothing should be worn (more than six cycles but not washed with fabric softeners)
  • In general sunscreen, lotions, moisturizers and makeup should be avoided before or during sampling and bottle handling
  • Non-powdered nitrile gloves should be worn

Even the simple act of picking up a breakfast sandwich on the way to a site prior to sampling can result in PFAS contamination of skin, clothing, and air in the vehicle, and without necessary precautions can result in cross contamination of samples.

Detailed guidance for PFAS sample collection has been developed by several organizations, including the Interstate Technology Regulatory Council, Battelle Memorial Institute, Michigan DEQ, and the National Ground Water Association (free to members).  Planning and experience are necessary for the successful sampling and analysis of PFAS in environmental media.  For more information or to discuss your sampling needs, contact the author.

Published in Cox-Colvin’s April 2019 Focus on the Environment newsletter.

As discussed in last month’s installment of Vapor Intrusion Fundamentals (Number 47), sanitary sewer lines are becoming recognized as an important, yet often overlooked, pathway for vapor intrusion (VI).  In this installment, we will review approaches used to evaluate sewer connections and deciphering the associated analytical data collected during VI assessments.                  

As a reminder, VI assessments can be thought of as a three-legged stool, with each leg representing a contributing source that must be understood:

  • contributions associated with soil gas,
  • contributions associated with indoor sources, and
  • contributions associated with preferential pathways.

Not understanding this third leg of VI assessment stool can lead to a misdiagnosis of the issues and implementation of ineffective mitigation efforts. 

The first step in the assessment of the vapor contribution associated with sewer gas is to develop a sound conceptual site model (CSM) that recognizes and anticipates this preferential pathway.  Trunk sewer lines, especially those is areas served by industries that used solvents, can transport volatile organic compounds over relatively long distances downgradient and contaminate environmental media (soil and groundwater) through degraded sections and defects in the lines. These areas should be thought of as secondary point or line sources.  Assessing the locations of these secondary sources can be done through detailed inspections of the lines using cameras. Many communities have done these studies in preparation for sewer improvement projects.

Understanding the potential effect of degraded sewers on your study area is an important aspect of the CSM and the overall evaluation of a neighboring buildings and/or houses, however, most investigations begin with an assessment of a single building.  You can get a sense of the potential contribution of sewer gas on your building through the collection of sewer gas samples from nearby manholes and cleanouts.  In addition to your chemicals of concern (e.g., chlorinated VOCs), you should also analyze for other chlorinated and brominated compounds (e.g., chloroform, bromoform, and bromodichloromethane), as these compounds are typically found in sanitary sewer gas as a result of the breakdown of household and industrial cleansers. 

As you begin your indoor air sampling campaign, review your sewer gas data closely.  If your chemicals of concern are found in sewer gas, then you should inspect the lavatories and areas containing floor drains as possible sampling locations.  If you collect samples from lavatories, conduct the sampling with the door shut and the fan running to induce air flow through plumbing leaks. After you receive the analytical results, review the dataset for the indicators of sewer gas (chloroform, bromoform, and bromodichloromethane) as well as the ratios of your chemicals of concern and compare them to your sub-slab and sewer gas data.  These comparisons will help you determine if the sanitary sewer represents a complete pathway for VI. In a recent study completed by Cox-Colvin, sewer gas was determined to be the primary pathway of VI at more than half of the buildings evaluated.

Accounting for the sewer gas VI pathway in your CSM provides you with additional insight into potential sources as well as appropriate means of mitigation. Sub-slab depressurization systems (SSDs) are very effective at interrupting the VI pathway associated with a sub-slab source; however, SSDs are typically not effective at mitigating the sewer gas source. If the VI pathway is dominated by the sanitary sewer line source, simple plumbing repairs could be enough to mitigate the VI issues.  

Published in Cox-Colvin’s April 2019 Focus on the Environment newsletter.

In general, Vapor Intrusion (VI) assessments can be thought of as a three-legged stool, with each leg representing a contributing source that must be understood; including:

  • contributions associated with soil gas,
  • contributions associated with indoor sources, and
  • contributions associated with preferential pathways.

Until recently, most assessment efforts (and modeling) have focused on the first two legs – understanding the contributions from soil gas and the contributions from indoor air. The third leg, contribution from preferential pathways, is generally given lip service but rarely evaluated in a rigorous manner.

In the past, the preferential pathway has been considered the trenching and permeable backfill associated with underground utilities.  However, when you consider that a sanitary sewer is essentially an air-filled conduit providing a direct vapor pathway into every inhabited building, more often than not, the sanitary sewer will be the preferential pathway of concern. 

Not understanding this third leg of VI assessment stool can lead to a misdiagnosis of the issues and implementation of ineffective mitigation efforts.  This is a game changer when you consider that:

  • sanitary sewers have been an integral part of the industrial waste elimination systems for years through permitted discharges to publically-owned treatment works (POTWs),
  • the “drain” has been an easily accessible disposal route for those that have used solvents and may not have obtained discharge permits,
  • sanitary sewers used by industry are, in many instances, the same ones used by homes in the same neighborhood,
  • sanitary sewers are typically plagued by failures or penetrations from tree roots,
  • sanitary sewers may extend below the water table (before entering a lift station), and
  • sanitary sewers contain a great deal of air-filled space that is essentially connected to every home and business along its route.

Plumbing traps (P-Traps) and seals (e.g., wax toilet rings) in our plumbing systems typically prevent the intrusion of sewer gas into our homes and businesses, and vent pipes on the soil stack allow these vapors to vent to the atmosphere.  However, P-Traps can dry out, wax rings can fail, and stacks within the home or business can develop cracks or other failures allowing vapors within the sewer to enter the indoor air space.

So how does this result in a misdiagnosis of the issue?  Let’s say you collect sub-slab soil gas and concurrent indoor air samples above VOC contaminated groundwater and find that similar compounds are detected in both.  This could look like a line of evidence indicative of VI. The tendency may be to mitigate with a sub-slab depressurization (SSD) system.  However, if the plume intersects the sanitary sewer line, or the bed of the sanitary sewer line is impacted by a history of solvent disposal, then the vapors may be coming into the indoor space through the sewer connection which will not be mitigated by SSD.  Instead, ensuring that the P-Traps are filled, replacing defective toilet seals and repairing sewer line breaks could mitigate the issue. In the end, it is important keep in mind all of the potential migration pathways when you develop your conceptual site model and take steps to evaluate each pathway before you move to mitigation.  In the next installment, we will review approaches used to evaluate sewer connections and deciphering the associated analytical data.     

Published in Cox-Colvin’s March 2019 Focus on the Environment newsletter.

On February 14, 2019, US EPA (EPA) announced the release of its per-and polyfluoralkyl substances (PFAS) action plan.  Consistent with the Administration’s first ever, best-ever marketing approach, the PFAS Action Plan is billed by Assistant Administrator David Ross (in his February 15 letter to Senator Thomas Carper) as the “first-ever PFAS Action Plan.”   The Action Plan describes EPA’s approach to identifying and understanding PFAS, addressing current PFAS contamination, preventing further contamination, and communicating with the public.  

The term PFAS refers to per-and polyfluoroalkyl substances. PFAS are a very large group of synthetic chemicals that have been used in a wide variety of consumer and industrial products since the 1940s.  Due to their widespread use and persistence in the environment, they are commonly found in human blood samples.  Current information suggests that continued exposure above specific levels to certain PFAS may lead to adverse health effects.  In 2016, EPA released lifetime drinking water Health Advisories for perfluorooctanoic acid (PFOA) and perfluoroctane sulfonate (PFOS), two of the chemicals in the PFAS family.  Health Advisories are non-enforceable and non-regulatory and provide technical information to state agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination. EPA first announced that it would be initiating steps to evaluate the need for a maximum contaminant level (MCL) for PFOA and PFOS in drinking water during the May 2018 EPA PFAS National Leadership Summit, and its decision on this has been highly anticipated.   

Unfortunately for some, EPA’s position as reflected in the Action Plan is not as clear as it could be, stating that “The EPA is committed to proposing a regulatory determination for PFOA and PFOS.” Committing to proposing a regulatory determination does not necessarily mean that EPA will promulgate an MCL.  The Safe Drinking Water Act (SDWA) requires EPA to consider the following three criteria when making a determination to regulate:

  • The contaminant may have an adverse effect on the health of persons
  • The contaminant is known to occur or there is a high chance that the contaminant will occur in public water systems often enough and at levels of public health concern
  • In the sole judgment of the Administrator, regulation of the contaminant presents a meaningful opportunity for health risk reductions for persons served by public water systems

When making the determination, EPA first publishes a preliminary regulatory determination in the Federal Register (FR) and provides an opportunity for public comment. After review and consideration of public comment, EPA publishes a final FR notice with the regulatory determination decisions. If EPA makes a decision to regulate a particular contaminant, the Agency starts the rulemaking process to establish the national primary drinking water regulation. It is entirely possible that the Agency may decide not to regulate a particular contaminant based on the three criteria.  For instance, in 2016 EPA announced the final determination not to regulate four contaminants on the third drinking water contaminant candidate list (CCL3) including dimethoate, 1,3-dinitrobenzene, terbufos, and terbufos sulfone.  

During the February 14, 2019 press conference announcing the Action Plan, when asked if it was possible that the determination may result in not setting an MCL, EPA Acting Administrator Andrew Wheeler answered “… we have, I have every intention of setting an MCL.” In a February 15, 2019 letter to Senator Thomas Carper, EPA Assistant Administrator David Ross confirmed EPA’s position stating that “The EPA intends to establish a maximum contaminant level (MCL) for PFOA and PFOS” and that “EPA is committed to following the MCL rulemaking process.”  No time frame is given for establishing an MCL, however, the Action Plan states that EPA will propose a PFOA and PFOS regulatory determination for public comment in 2019.  

Assuming EPA makes the decision to regulate the contaminant in drinking water, the agency begins the rulemaking process to establish a national primary drinking water regulation.  After reviewing health effects data, EPA sets a maximum contaminant level goal (MCLG) for the chemical. MCLGs are non-enforceable public health goals. MCLGs consider only public health and not the limits of detection and treatment technology effectiveness. Therefore, they sometimes are set at levels which water systems cannot meet because of technological limitations. Once the MCLG is determined, EPA sets an enforceable standard. In most cases, the standard is an MCL. The MCL is the maximum level allowed of a contaminant in water which is delivered to any user of a public water system. It is set as close to the MCLG as feasible, taking costs into consideration, which can result in an MCL significantly higher than the MCLG.  When there is no reliable method that is economically and technically feasible to measure a contaminant at concentrations to indicate there is not a public health concern, EPA sets a “treatment technique” rather than an MCL. A treatment technique is an enforceable procedure or level of technological performance which public water systems must follow to ensure control of a contaminant. 

The decision to regulate and to develop a national primary drinking water regulation for a new contaminant is a big deal.  It does not happen often, and it will not happen overnight.  For this reason, as well as the general lack of federal leadership and commitment on the issue, several states including Pennsylvania are moving forward with their own MCL. In this era of de-regulation, we can be glad that there is a process which relies heavily on public involvement and can only hope that decisions are made based on the best science available.

Published in Cox-Colvin’s March 2019 Focus on the Environment newsletter.


Updated Map Tracks PFAS Contamination in the U.S.

  • By: Doug
  • Posted: 05/22/19

On May 6, 2019, the Environmental Working Group and the Social Science Environmental Health Research Institute at Northeastern University released the latest update of their interactive map  documenting the publicly known contamination from PFAS chemicals in the United States.   At least 610 locations, including public water systems, military bases, military and civilian airports, industrial plants, […]

The Dry Cleaner Dilemma

  • By: Craig
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There are, or have been, thousands of small commercial dry cleaning operations throughout the U.S. – nearly every neighborhood had one. Most of them are, or were, small family owned businesses that started in the 30s, 40s, or 50s.  Many of these facilities became ‘anchor’ stores of small shopping centers that are now being redeveloped.  […]

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  • By: Nick
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The term PFAS refers to per-and polyfluoroalkyl substances, which comprise thousands of synthetic chemicals that have been used in a wide variety of consumer and industrial products since the 1940s.  PFAS is quickly becoming  the hottest topics in the environmental field  due in part  to numerous State-lead initiatives, work groups, and EPA’s February 14, 2019 […]

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  • By: Nate
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On April 25, 2019, US EPA (EPA)  released, for public comment, draft recommendations for addressing  groundwater contaminated with perfluorooctanoic acid (PFOA) and/or perfluoroctane sulfonate (PFOS) under federal cleanup programs, including the Comprehensive Environmental Response Compensation and Liability Act (CERCLA or Superfund) and site-wide corrective action under the Resource Conservation and Recovery Act (RCRA).  Development and […]

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PFAS Sample Collection

  • By: Steve
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As discussed in another article in this newsletter, some states have established drinking water standards for per-and polyfluoroalkyl substances (PFAS), or they are in the process of doing so. The standards being adopted are low – in the nanograms per liter (ng/L) or parts-per-trillion (ppt) range – and require very low laboratory detection limits. The […]

Vapor Intrusion Fundamentals 48 – Sanitary Sewers, the Preferential Pathway, Part 2

  • By: Craig
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Vapor Intrusion Fundamentals 47 – Sanitary Sewers, the Preferential Pathway, Part 1

  • By: Craig
  • Posted: 03/19/19

In general, Vapor Intrusion (VI) assessments can be thought of as a three-legged stool, with each leg representing a contributing source that must be understood; including: contributions associated with soil gas, contributions associated with indoor sources, and contributions associated with preferential pathways. Until recently, most assessment efforts (and modeling) have focused on the first two […]

EPA’s Signal Intent to Move Forward with MCL Process for PFAS

  • By: George
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