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Radon in Schools: Despite state and federal recommendations, only 53 of 331 school districts in Minnesota report they have tested classrooms for radon since 2012. KARE 11 found out which Twin Cities area districts are testing – and which ones are not.

Hollywood recognizes Radon: Shantel VanSanten has turned a personal tragedy into a catalyst for helping others. After her grandmother passed, VanSanten and her family looked for answers, and were shocked at what they found. “We searched to understand what the cause was, and we found it was from radon poisoning, which was found in [her] basement.”
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Vapor Pin Newsletter


To signup for the newsletter, please send an email to Laurie_Chilcote@vaporpin.com

 May 2018

Article

In 1991 Paul Johnson and Robert Ettinger, then of Shell Development Company, developed a complex mathematical model to predict vapor intrusion from subsurface contamination. As vapors migrate from source to receptor, their concentrations are attenuated (lessened) by varying degrees, depending on a number of factors, including: Building size, Soil-gas entry rate, Building air exchange rate, Soil type, Soil porosity, Soil moisture content, Depth to source, and Chemical-specific volatilization from groundwater.

The model did not take into account chemical breakdown, which is typically much more rapid for petroleum hydrocarbons (PHCs) than for chlorinated volatile organic compounds (CVOCs).

In 2003 EPA incorporated the J&E model into spreadsheets to calculate VI from soil, groundwater, soil gas, and Non-Aqueous Phase Liquids (NAPLs). The spreadsheets calculated not only indoor vapor concentrations, but also the risk to building occupants, based on EPA Regional Screening Levels (RSLs) for each chemical, and exposure factors, such as exposure time. There were some serious limitations with the spreadsheets. One was that the risk factors built into the spreadsheets were not easily updated. Users had to use a password to unlock the spreadsheets and change risk parameters, such as Reference Concentrations (RfCs), to match the latest Regional Screening Levels (RSLs). In 2004 EPA revised the spreadsheets with updated RSLs, but RSLs continue to change over time. In 2004, EPA also dropped the NAPL spreadsheets and soil spreadsheets, due to questions regarding their ability to estimate VI with any kind of accuracy.

There were other problems with EPA spreadsheets as well. Paul Johnson, coauthor of the J&E model, was critical of EPA’s spreadsheet version for various reasons, including the fact that the spreadsheets had built-in automatic checks for numerical errors, but there were no built-in reasonableness checks, making it possible to enter wildly inappropriate and conflicting data. Similarly, coauthor Robbie Ettinger made the point that while EPA’s spreadsheets incorporated the J&E algorithm, they were separate from the J&E model, and he did not agree with everything in them. Not surprisingly, after EPA released a report titled, “Uncertainty in the Johnson-Ettinger Model for Vapor Intrusion Calculations” in September 2005, states started to disallow the use of J&E modeling.

The latest version of EPA’s Spreadsheet for Modeling Subsurface Vapor Intrusion remedies many of the problems. Because the revised spreadsheet is linked directly to EPA’s RSLs, there is no longer any lag between them, and the complications of entering risk factors are avoided, providing that state or other jurisdiction accepts US EPA’s factors. (Some states, particularly California, often disagree with US EPA’s risk factors). The revised spreadsheet is also simpler in that groundwater and soil gas are entered into the same spreadsheet. The earlier versions had separate spreadsheets for each. The updated model also displays many of the calculations on the main page, such as Qsoil and Qbuilding, the rate at which soil gas and outdoor air, respectively, enter a building. Previous spreadsheets displayed the calculations on separate pages, and in a way that was harder to interpret. Additionally, the revised J&E model performs calculations for multiple chemicals on a single spreadsheet, instead of requiring a separate one for each chemical. This will save a lot of paper!

More importantly, like EPA’s earlier spreadsheets for J&E modeling, the updated spreadsheet is less conservative than default Vapor Intrusion Screening Levels (VISLs), making unnecessary vapor mitigation for low-risk sites less likely. For example, using Excess Lifetime Cancer Risk of 10E-5, Hazard Quotient (HQ) of 1, and groundwater temperature of 11 degrees Centigrade), the residential groundwater VISL for trichloroethene (TCE) is 9.9 micrograms per liter (ug/l). However, the revised J&E spreadsheet indicates that TCE in groundwater, using the same settings, has a target concentration of 19.4 ug/l. Additionally, using the J&E model, the acceptable concentrations of chemicals in soil gas or groundwater can be considerably higher than VISL levels, depending on soil type, depth to source, and other factors. Using the same default factors in the J&E model, but changing the soil type from sand to loam, (a mixture of sand, silt, and clay), raises the allowable level of TCE in groundwater to 194 ug/l. And unlike the revised VISL calculator, you can make changes to the J&E spreadsheets after downloading them to your computer and exiting EPA’s website.

A technical problem with the revised J&E spreadsheet is that the earlier-mentioned Qsoil/Qbuilding ratio is currently fixed at 0.003. This hairy looking factor boils down to the rate at which subslab soil gas (Qsoil) mixes with indoor air (Qbuilding) – “Dilution is the solution to pollution”, as they say. For now, changing the Residential setting to Commercial/Industrial automatically increases the ceiling height, air exchange rate, and slab thickness, which is helpful, but the dilution ratio, Qsoil/Qbuilding, stays at 0.003, and is taken from a lookup table, not calculated. According to Rich Kapuscinski, EPA’s website content manager, “We are and will be expeditiously addressing these problems, as we intend to have (and publish) a (revised) tool that is suitable for commercial, as well as, residential buildings.”

The other issue with the revised J&E model will be its acceptance by state and local agencies.

Author: Mort Schmidt is a Senior Scientist with Cox-Colvin & Associates, Inc. He received his BS and MS degrees in Geology and Mineralogy from The Ohio State University, and has been a Cox Colvin & Associates employee since 1997. His areas of expertise include vapor intrusion and contaminant investigation and analysis, and he currently serves as Cox Colvin’s Practice Leader – Vapor Intrusion Services. Mort is a Certified Professional Geologist with AIPG and is a registered Geologist in Indiana.

Events

May 15-16, 2018: Craig Cox, CPG and Laurie Chilcote will be at the Texas Commission on Environmental Quality – Environmental Trade Fair and Conference at the Austin Convention Center in Austin, TX. Come see us at Booth 525!

May 16-18, 2018: Craig Cox, CPG and Laurie Chilcote will be at the 47th Environmental Show of the South in Chattanooga Convention Center, Chattanooga, TN – in Booth 319!

Click here to find where to get your Coupon Code!!!  sw-esos-exhibit-hall-map

Craig Cox will be presenting: Locating and Assessing the Age of VOC Sources Beneath Large Buildings on May 17, 2018, Afternoon Session – Vapor Intrusion Track, Room 11, at 1:10pm.

Please join us for the Brazil Workshops in June 2018: June 21, 2018: Workshop in Porto Alegre on June 19, 2018, Critiba on June 21, 2018, and Sao Paulo on June 25, 2018.

Radon News

Radon in Schools: Despite state and federal recommendations, only 53 of 331 school districts in Minnesota report they have tested classrooms for radon since 2012. KARE 11 found out which Twin Cities area districts are testing – and which ones are not.

Hollywood recognizes Radon: Shantel VanSanten has turned a personal tragedy into a catalyst for helping others. After her grandmother passed, VanSanten and her family looked for answers, and were shocked at what they found. “We searched to understand what the cause was, and we found it was from radon poisoning, which was found in [her] basement.”

April 2018

Article

EPA Updates Vapor Intrusion Screening Level Calculator

In February 2018, US EPA updated its Vapor Intrusion Screening Level (VISL) Calculator in a number of ways. The VISL Calculator now consists of an online calculator, instead of a downloadable spreadsheet, and it is in most respects, more powerful and easier to use. For more information, read on….

To use the VISL Calculator, one enters the chemicals of interest, and other inputs including Hazard Quotient for non-carcinogens (typically 1), Target Cancer Risk (10-6, 10-5, 10-4, or other), Exposure Scenario (residential vs commercial), and chemical names. The user then hits the Retrieve button and a new window opens up with the results. One can opt to:

  • View the results online
  • Output the files to an Excel worksheet
  • Output a series of tables in PDF format

The revised VISL calculator represents a considerable improvement over the earlier VISL Calculator, and selecting the chemicals of concern is easier in most respects. On the plus side, unlike the earlier spreadsheet-based versions, the chemical names include a number of synonyms and Chemical Abstracts Services (CAS) numbers. One can select benzene, for example, by typing in “benzene”, “benzol”, “phenyl hydride”, “71432”, etc. The earlier VISL calculator provided only a few synonyms, and while you could select chemicals via name or CAS numbers, you couldn’t do both. If you selected a number of chemicals via name and then selected one via CAS number, all of the earlier selections were lost. Now you can mix and match. Unfortunately, the new VISL Calculator displays only 7 or 8 chemicals at a time, and scrolling down through the window to pick a chemical from the very long list is time consuming. In general, it’s easier to select a chemical by typing in part of the chemical’s name, but the entry “benzene”, for example, brings up more than 130 chemicals, and they’re not in alphabetical order. It might be easier if the VISL Calculator opened up a larger window in which more chemicals could be seen at once.

As discussed earlier, the new calculator is not a downloadable spreadsheet, but it can output spreadsheets showing the results. But because the spreadsheets contain no hidden information or calculations, it’s impossible to add to the chemicals of concern or to modify risk settings, groundwater temperature, etc., after leaving the website. If you wish to add chemicals or change settings, you’ll have to return to the online calculator and start over.

A potentially useful feature of the revised VISL Calculator is the ability to modify the soil-gas or groundwater attenuation factors. As discussed in the July 2014 issue of Focus on the Environment, attenuation factors represent the ratio between indoor air and subsurface vapor concentrations. The default soil-gas attenuation factor is 0.03, but the measured attenuation factor, according to EPA’s Vapor Intrusion Database report, (2012) is 0.003. The risk is intentionally exaggerated by a factor of 10 to allow for a safety margin. This makes sense to a point, but the higher ceilings, greater air-exchange rates, and other conditions characteristic of commercial/industrial settings result in even lower actual attenuation factors. Cox-Colvin routinely sees actual soil-gas attenuation factors in commercial/industrial settings of 0.0001 or lower, where indoor air is okay, even though soil gas concentrations greatly exceed soil-gas VISLs. So the ability to match attenuation factors to site-specific conditions will enable the use of more realistic – but still protective – VISLs. However, convincing regulators to accept less conservative attenuation factors for commercial/industrial settings might be difficult, and you or your consultant will need a good understanding of attenuation factors to justify their use.

Another advantage of the revised VISL Calculator is that it’s now tied directly to EPA’s Regional Screening Level (RSL) database, and VISLs are updated automatically with RSLs. The older spreadsheet-based calculator was updated periodically, but screening levels lagged the latest RSLs. Additionally, the list of substances in the new VISL Calculator includes more constituents, including Total Petroleum Hydrocarbons (TPHs), which are useful at petroleum sites. And finally, the new VISL Calculator outputs metadata, including inhalation Unit Risk Factors, Inhalation Reference Concentrations, and other information that risk assessors may find useful.

In all, the revised VISL Calculator is a step forward, but you might be wise to have CAS numbers handy when selecting chemicals, and don’t leave the website until you’re done selecting.

Author: Mort Schmidt is a Senior Scientist with Cox-Colvin & Associates, Inc. He received his BS and MS degrees in Geology and Mineralogy from The Ohio State University, and has been a Cox Colvin & Associates employee since 1997. His areas of expertise include vapor intrusion and contaminant investigation and analysis, and he currently serves as Cox Colvin’s Practice Leader – Vapor Intrusion Services. Mort is a Certified Professional Geologist with AIPG and is a registered Geologist in Indiana.

Events

April 22-24, 2018: Laurie Chilcote will be with our distributors Hoskins Scientific at the Canadian Association of Radon Scientists and Technologists in Ottawa, Ontario, Canada

May 15-16, 2018: Craig Cox, CPG and Laurie Chilcote will be at the Texas Commission on Environmental Quality – Environmental Trade Fair and Conference at the Austin Convention Center in Austin, TX. Come see us at Booth 525!

May 16-18, 2018: Craig Cox, CPG and Laurie Chilcote will be at the 47th Environmental Show of the South in Chattanooga Convention Center, Chattanooga, TN – in Booth 319.

Craig Cox will be presenting: Locating and Assessing the Age of VOC Sources Beneath Large Buildings on May 17, 2018, Afternoon Session – Vapor Intrusion Track, Room 11, at 1:10pm.

Radon News

Engineering Extension announces new Radon Chamber Services for Radon Industry: The radon programs conducted by Engineering Extension have added a new service for the radon industry. A nationally certified and state licensed radon chamber is now operating in Engineering Extension at the Unger Complex. This chamber will be used for device performance testing and spiking services in support of the radon industry. The chamber was transferred from the Radon Measurements Laboratory in Colorado Springs in March and began services on April 9. Bruce Snead, Director of Engineering Extension is leading this new initiative. More information is available at ksuradonchamber.org and by contacting Bruce at bsnead@ksu.edu.

Save the date – State Radon Resistant New Construction Laws (2017): Visit AARST’s State Radon Policies for 2017 or search the National Conference of State Legislatures database for the latest details on radon policies/laws by state.

March 2018

Article

Vapor Intrusion – The Four Horsemen: Benzene, Chloroform, Naphthalene, and Trichloroethene

In vapor intrusion, “background” is contamination in indoor air that came from outdoor (ambient) air or from interior sources, such as cleaning products, paints, and plastics. Owners of facilities associated with soil or groundwater contamination might be obliged to mitigate vapors at their own and at surrounding properties, and if they can’t distinguish between vapor intrusion and background, they might be paying for someone else’s problem. Worse, most vapor-mitigation systems prevent soil gas from entering the building, and if vapors are from background, the system won’t help.

EPA’s 2011 report on background contamination shows some interesting trends. The authors compiled the results of indoor-air samples collected from residences with no known or suspected vapor intrusion. As seen in Figure 4 from this report, below, benzene, chloroform, and TCE were present in 91%, 68%, and 43% of residences, respectively. Naphthalene does not appear on this graph, because its molecular weight is somewhere between those of volatile organic compounds (VOCs) and a semi-volatile organic compounds (SVOCs), and was often excluded from VOC sampling. But the toxicity and volatility of naphthalene, together with its widespread occurrence in background, have earned it a place on the list of vapor-intrusion compounds, and on the list of problem compounds. According to the Montana Department of Environmental Quality’s 2012 background investigation, naphthalene was detected in 40 out of 50 residences with no known vapor intrusion.

Figure from USEPA 2011, Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences, EPA 530-R-10-001.

Where do these compounds come from? Benzene is the B in BTEX – benzene, toluene, ethylbenzene, and xylenes, all of which are widely associated with gasoline and other fuels. Benzene poses the greatest problem of the BTEX compounds, since the other three have comparatively low toxicity. Benzene is also the base for countless manufactured chemicals, so of course, benzene is commonly detected in the subsurface, and is a common constituent of concern for vapor intrusion. Benzene is also ubiquitous in ambient air, especially in metropolitan areas, due to vehicular traffic and fuels. Benzene also can be expected in background in buildings with attached garages, due to its presence in vehicular gas tanks, gas-storage cans, and lawn equipment.

Chloroform is normally present in chlorinated water, and not surprisingly, chlorine is common in indoor air. But tap water is not the only source, and perhaps, not the most important source of chlorine in indoor air. At vapor-intrusion conferences, speakers often report high levels of chloroform in indoor air, but when I ask them where they think it came from, they rarely have an answer. However, a number of recent investigations have focused on sewer gas, and found that dry plumbing traps, breached toilet-wax rings, loose pipe fittings, and other conditions often allow sewer gas to enter buildings, bringing chlorine with it. Whatever the source of chloroform in background, Massachusetts’ 2008 Technical Update – Residential Typical Indoor Air Concentrations indicates a median concentration for chloroform of 1.9 ug/m3. The residential VISL in Ohio is 1.2 ug/m3. Good luck with that.

At one time, naphthalene was the main ingredient in mothballs, but it’s been replaced by chlorinated compounds to reduce the risk of fire. Naphthalene is typically associated with coal and the heavier petroleum oils. Naphthalene has the lowest residential indoor-air VISL of the big four compounds, at 0.83 micrograms per cubic meter (0.83 ug/m3), using Ohio standards of 10-5 cancer risk, and a hazard index of 1 for non-carcinogenic compounds. Consequently, the lab’s reporting level for naphthalene, even using 6-liter “Summa” cans, might exceed indoor air screening levels, unless results are reported to Method Detection Levels (MDLs). Reporting to MDLs generally results in the detection of numerous additional compounds, making data validation and interpretation more complicated and costly. The additional information seldom changes the final assessment, but if ya’ gotta, ya’ gotta.

And, finally, TCE rounds out the list of four bad players. We’ve discussed TCE a number of times, including in the August 2017 edition of Focus on the Environment, but in case you haven’t heard, TCE drives most of the vapor-intrusion work in recent years, due to concerns over fetal heart defects. Much or most of the concern with vapor intrusion is tied to the risk of cancer, which generally develops over years or decades. Although, as discussed in previous articles, the link between TCE exposure and fetal heart defects is in doubt, EPA assumes that a single day of exposure to TCE is sufficient to cause harm, so regulatory agencies are prioritizing TCE sites and pushing for rapid vapor-intrusion assessments.

How do we deal with these four compounds in vapor intrusion? Primarily, one establishes whether they’re from vapor intrusion or background. This involves:

  • Determining if indoor constituents are present in soil gas. If not, they’re probably from background.
  • Comparing indoor air to outdoor ambient air. Contaminants in outdoor air represent, by definition, background.
  • Comparing ratios of indoor constituents to soil-gas constituents. Vapor migration from subslab to indoor air involves only dilution, so the ratios of chemical concentrations in indoor air should be pretty much the same as the ratios in soil gas.
  • Conducting a survey of vapor-forming substances inside the building as part of the initial vapor-intrusion assessment. Compounds with anomalously high concentrations in indoor air may be associated with these materials, or with activities and substances used during sampling.
  • Comparing indoor-air concentrations to EPA’s background report, and others. Common background constituents, e.g., BTEX, should generally be regarded as suspect.

More often than not, one or more of the problem compounds represent background, and cumulative risk from the remaining compounds is acceptable. Understanding the sources and significance of these four compounds is critical to eliminating unnecessary costs and efforts.

Author: Mort Schmidt is a Senior Scientist with Cox-Colvin & Associates, Inc. He received his BS and MS degrees in Geology and Mineralogy from The Ohio State University, and has been a Cox Colvin & Associates employee since 1997. His areas of expertise include vapor intrusion and contaminant investigation and analysis, and he currently serves as Cox Colvin’s Practice Leader – Vapor Intrusion Services. Mort is a Certified Professional Geologist with AIPG and is a registered Geologist in Indiana.

Events

March 20, 2018: Craig Cox, CPG will be presenting two posters during the Poster Sessions at the 28th Annual International Conference on Soil, Water, Energy, and Air. (Abstract numbers: 144 & 145) Come see the Mini-PinTM at booth 33!

April 8-12, 2018: Craig Cox, CPG will be speaking and presenting a poster at the Eleventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Abstract number: 11, Session: H3. High-Resolution Site Characterization (HRSC), Presentation date and time: 4/11/18. 4:30pm- 6:30pm) Come see Vapor Pin® Enterprises & the Mini-PinTM at booth 304!

April 12, 2018: Please join Craig Cox, CPG and Laurie Chilcote at the Learning Lab Demonstration to be held, from 8:50am to 9:15am, at the Eleventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds. They will be demonstrating Tips and Techniques: Pilot Testing, Pressure Field Verification, Locating VOC Sources, and Evaluating VI Pathways using the Vapor Pin® . Come see Vapor Pin® Enterprises & the Mini-PinTM at booth 304!

Radon News

Radon Outreach & Education: The Ohio Indoor Radon program operates a federally funded indoor radon grant in cooperation with the U.S. Environmental Protection Agency (U.S. EPA) and a network of local health departments within the State of Ohio. Elevated levels of indoor radon is the primary cause of lung cancer among non-smokers. The United States Surgeon General warning: Radon Causes Lung Cancer – You Should Test Your Home.  For information on radon, click on the FAQ link to the left or call the ODH Radon Information Line, toll-free, at 1-800-523-4439.

Click here to read the latest on Ohio Radon News

Radon in Drinking Water: In many countries, drinking water is obtained from groundwater sources such as springs, wells and boreholes. These sources of water normally have higher concentrations of radon than surface water from reservoirs, rivers or lakes. To date, epidemiological studies have not found an association between consumption of drinking-water containing radon and an increased risk of stomach cancer. Radon dissolved in drinking-water can be released into indoor air. Normally, a higher radon dose is received from inhaling radon compared with ingestion. Click here to read more…