FLUXOLOGY REPORT 4
Greetings and good cheer to all! Perhaps it’s just me but the years seem to fly by at ‘Warp 9 Speed!’ I don’t know if that’s good or bad, but it’s high time I greet my friends and embrace my task as chief cook and bottle washer responsible for publishing a current ‘Fluxology Report!’ God’s richest blessings on you and may you know Him better this year.
Life is ‘rich and full’ as ‘they’ say and my family is doing just great. After 2 ½ years of caring for my Mom here at home serving her special needs, at doctors recommendation we moved her to a memory care assisted living residence. Thanks to my wonderful wife and daughter (AKA- wonder women), we were able to help her at home, and continue to do so at the assisted living residence. Katie is off to college in August, so keep those jobs and checks coming! Also we inherited a 3 year old, 160-pound St. Bernard puppy that is presently eating us out of the house and farm. He’s great, but he just doesn’t seem to understand why it not good to slap his little paws on my shoulder tops and lay a luggy on my face; more fun than I can describe (see photo of horse-dog). Mr. Hoby Rash is still providing tremendous support for our field testing efforts and has assumed the responsibility of catching all of my screw-ups in the field making for successful and cost-effective projects. His work is excellent and he is experienced in flux chamber testing, ambient air monitoring, and specialty sample collection techniques. With an affordable charge rate, he is a value-added component to any program. Remember that he is available to execute programs that don’t involve me or flux chamber testing, and he continues to provide consulting services related to permitting, compliance for the power industry, and even doing research for toxicologists collecting primary literature references via Internet. I am so jealous; he has Internet satellite and can download documents at incredible rates. I still have the wax string/tin-can model link to the land grid, which amounts to three line pairs and a shoebox on the power pole down the street! He has been working with our friend and colleague Dr. Alvin Greenberg on these types of programs and you can reach him at (530) 529-3108.
Business has been good and we are blessed with interesting and challenging projects that seem to be focused on very special needs of site owners. I looked over the list of projects for the past two years and here is the breakdown: 43 site assessments, 25 compliance projects, 6 formal building infiltration projects, and support for 3 litigations. The data uses for the site mitigation projects usually focused on land resale and redevelopment (photo #1) and, as such, many of these efforts are actually current or potential exposure assessments supporting site-specific health risk assessments. Most of the compliance projects had to do with emissions from wastewater treatment facility emissions (photo #2) or solid waste composting operations (photo #3). Many of these projects were in support of engineering evaluations which will hopefully lead to the development of new ways to solve old problems, which is always fun.
These projects, including the litigation support projects, seem to be straightforward compared to the more controversial structure infiltration and exposure to indoor air contamination projects. It is apparent to me that the application of the USEPA surface emission isolation flux chamber (flux chamber) to sites with potential infiltration into existing and proposed structures is hotly debated. It seems like folks are divided into one of three schools of thought on this topic, all of which result in support of an exposure/health risk assessment: 1) soil gas testing (geoprobe, canister sample collection and TO-14 or TO-15 analysis) and predictive modeling (typically J&E); 2) ambient air monitoring (integrated canister sample collection and TO-14 SIM analysis); or 3) area source assessment using the USEPA flux chamber and ventilation calculation.
Many more folks joined the controversy when several applications of the J&E predictive model ‘under predicted’ potential exposure. Not to worry, nothing has changed. Predictive modeling is still a screening-level technology and it can lead to both gross under as well as over predictions of exposure. As was the case with these infamous ‘under predictions’ in screening, there is usually something about the site that the model didn’t simulate, like channeled groundwater flow or conduits resulting in unknown and unpredicted infiltration. In my opinion, the indoor infiltration issue is very complicated with site-specific circumstances that somewhat limit assessment technologies most of the time! As such, I typically propose all three approaches used in concert as an air pathway analysis (APA) to provide the project toxicologists data from all three approaches for risk assessment.
Why? Because the source of exposure via this pathway is sneaky and often found at low levels making it hard to detect, many of the common subsurface compounds are found in the workplace ambient air or are ubiquitous in the urban environment, and the exposure potential is very real and much more significant than outdoor air exposure to receptors from subsurface area sources. There is no simple assessment approach for this exposure pathway, agencies struggle with assessing health risk from this scenario, and liability for site owners and employers is ever-present. Designing and implementing an APA is really the only sure way of assessing potential exposure and data from all three assessment approaches (predictive modeling from soil gas, area source flux assessment, and endpoint indoor air quality data) is needed for a proper evaluation. Everyone is very passionate about this topic right now, which is great because passion breeds debate, debate leads to applied research, and applied research results in a better understanding through publication and education. My circle of buds and I have produced a half-dozen papers on this topic in the past year alone! So….if you find that you need to conduct an APA on your site that has the potential for indoor exposure to gas phase contaminants found below the site structure (or worse yet off-site structure), please give me a call.
Hoby and I can typically conduct an adequate indoor infiltration APA with one day of on site testing. With the predictive modeling already done prior showing the potential for exposure via infiltration, the remaining direct-measure APA typically includes: 8-to-10 outdoor open soil flux measurements around the structure and over the worst-case plume footprint (photo #4); 2) seam/crack screening on the slab and 8-to-10 infiltration flux measurements on bare slab (photo #5); and 4-to-6 outdoor/indoor ambient air measurements (photo #6) used to support the infiltration source data assessment. With the USEPA TO-14 SIM analysis MDL at around 0.010 ppbv MDL (wow!) or less, the selectivity and sensitivity satisfies even the most conservative toxicologist. We even figured out a way to collect measured flux data under a negative pressure environment (-2 to –10 Pascal) using The Negative Pressure Enclosure- NPE (photo #7), although one of my dogs is still quite upset with me (photo #8).
We have had many great projects with both new and old friends over past recent years or so, and it’s great fun to meet-up at conferences with you all and share good times again. Let me know if you can use my help on any projects this year. Also, please let me know if you need any of the publications listed on the web site.
If you find yourself up this way please stop and visit with us. We have a guest house that is sadly empty most of the time and a tired but functional houseboat on Lake Shasta. We would love your company. Plus ‘Heiny’ (short for Einstein) has a big wet kiss for you!
Take care friends!
Still alive and kick'n .... in Dead Bluff.....