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Get to Know a Scientist Emeritus—Thomas Imbrigiotta

This is the fifth in a series of Get to Know posts highlighting and celebrating the contributions of exemplary Scientists Emeriti. Their work, experience, and contributions are essential to the mission of the USGS.

As an emeritus, Tom has lead-authored the USGS Techniques and Methods report on passive sampling of groundwater wells, a topic he was instrumental in developing. In particular, Tom developed and demonstrated use of regenerated cellulose dialysis membrane (RCDM) technology for passive sampling of a wide variety of chemicals, and has since transferred his expertise to hydrologists in the New Jersey Water Science Center and others in the USGS. Tom is also a respected mentor for younger hydrologists working with water quality issues regarding the fate, transport, and remediation of volatile organic compounds in fractured rock aquifers and has been a valuable resource for advice on emerging per- and polyfluoroalkyl substances contamination issues.

Richard H Kropp
Director, USGS New Jersey Water Science Center


Thomas Imbrigiotta prepares to deploy well sampling devices - test
A regenerated cellulose dialysis membrane (RCDM) passive sampler and a polyethylene diffusion bag (PDB) sampler being recovered from a well at Naval Base Ventura County, Port Hueneme, CA. Credit: Joey S. Trotsky, US Navy. 

What attracted or brought you to work for USGS in the first place?

I got the job by luck – I was running out of money on my graduate assistantship in the fall of 1977 and I was married and wondering what I was going to do. I had finished the course and lab work for my master’s thesis at the Water Chemistry Department at the University of Wisconsin, but there was no funding for me to stay on and write up the thesis. As luck would have it, someone at the USGS in Indiana knew someone in the Water Chemistry Department and called to find out if they were interested in a vacancy to study ground water contamination. Fortunately for me, that person was going on for a PhD, and referred them to me. The USGS saw a parallel with the chemistry of lake sediments and groundwater aquifers, so I drove to Indiana to interview for the job in person and got it.

How long did you work at USGS before you retired and how long have you been an Emeritus?

I worked at USGS for 41+ years (7 in Indiana and 34+ in New Jersey) before I officially retired. I became an Emeritus as soon as I retired in January 2019 (in the middle of the last government shutdown)! It was very exciting to retire during the shutdown – I wasn’t sure whether I was actually retiring, or if I had to wait until we opened up again. It turned out the people who processed my paperwork were still working, though it did take a while to get my last paycheck.

What was your last title/position at USGS before you retired and became an Emeritus?

I was the Senior Hydrologist in the New Jersey Water Science Center (NJWSC), the Project Chief of the Naval Air Warfare Center (NAWC) Navy project (a 24-year long project with the Navy and a USGS Toxics Substance Hydrology research site that studied chlorinated solvent contamination in a fractured rock aquifer), and in charge of Groundwater Contamination Studies Program Development in the NJWSC. Though I worked on research projects much of my career, I never became a Research Grade Evaluation (RGE) Scientist. I was also a Supervisory Hydrologist for five years and the NJ Water Quality Specialist for two years.

What Science Center do you answer to as an Emeritus?

The New Jersey Water Science Center in Lawrenceville, NJ.

Thomas Imbrigiotta preps for well sampling
Measuring water levels in a multi-level packer well for the 2008 bioaugmentation study at the NAWC research site, West Trenton, NJ. Credit: Daniel J. Goode, USGS. 

What are you most proud of during your career with the USGS? OR describe a highlight of your career.

I am most proud of my work in developing a regenerated cellulose dialysis membrane (RCDM) passive diffusion sampler for use in groundwater wells. I and several colleagues worked on this for about 10 years during the 2000s and proved that these samplers work as well as sampling a well by pumping it. These samplers are basically dialysis membrane tubes filled with distilled water that you hang in a well. The contaminants in the well water diffuse across the semi-permeable membrane and equilibrate into the distilled water over time. Then you retrieve the sampler from the well, transfer the water to sample bottles, and send them off for analysis. These samplers can be used to collect both organic and inorganic compounds and appear to work for per- and polyfluoroalkyl substances (PFASs) also. These samplers work especially well at groundwater contamination sites because they reduce time in the field for sampling crews, eliminate the need to clean sampling equipment between wells, and eliminate the production of most all contaminated purge water which is expensive to collect, transport, and treat.

I am also proud of my work with the USGS Toxic Substances Hydrology Program at two sites. Toxics was a big program that started in the early 1980s that looked at the fate and transport of a number of different types of contaminants (sewage effluent, petroleum products, creosote, volatile organic compounds (VOCs), and trace metals) at different sites with differing geology across the country. I was the Project Chief of the Picatinny Arsenal research team looking at the processes that controlled the fate and transport of chlorinated VOCs, particularly trichloroethene (TCE) in a sand-and-gravel aquifer. Our work quantified the relative magnitude and importance of the processes of volatilization, sorption, biodegradation, dispersion, advection, and pump-and-treat removal that were acting on TCE as it was transported through the groundwater system. I was also part of the research team at the Naval Air Warfare Center (NAWC) Toxics research site that studied the fate, transport, and remediation methods for chlorinated VOCs in a fractured rock aquifer. The NAWC was a jet-engine testing facility for many years where the Navy managed through leaks and spills to severely contaminate the underlying siltstone and mudstone aquifer with chlorinated VOCs, particularly TCE. The site is located only seven miles from the NJWSC office, so it was a very convenient as well as an interesting place to work. The USGS started working at the stie in 1995 as a consultant for the Navy and became a Toxics research site in 2003. While others worked on defining the geologic framework and groundwater flow paths, I helped interpret the groundwater quality and investigated different ways to collect valid waterquality samples over the years. I first worked on my RCDM samplers at this site. In the last project I worked on before retirement, I helped develop a net-zero volume downhole sampling device to determine sorption, desorption, and biodegradation rates of VOCs in fractured rock boreholes. My working at both of these toxics sites was extremely interesting and allowed me to work with some of the finest research scientists in the USGS.

I am also proud of helping organize and present a series of workshops in the early 1990s on the proper sampling procedures to use to sample wells for VOCs. This was back before many of the current sampling protocols were written into the USGS Field Manual. We held workshops in what were each of the four regions (back then) and at the Denver Training Center primarily for USGS hydrologists and hydrologic technicians who were out in the field trying to collect valid samples. This workshop eventually was lumped into a USGS training class that covered both surface water and groundwater sampling for all organic compounds, but for 3-4 years, we were on the road a lot. 

And finally, I am very proud of the work I have done mentoring many summer interns, volunteers, and young hydrologists. For at least 10 years, the NAWC site was able to afford either a Pathways intern or a National Association of Geology Teachers (NAGT) intern each summer. I enjoyed showing them the ropes about doing real field work, sampling wells, constructing passive samplers, and collecting cores. At least four of them actually were hired by USGS offices after they graduated.

Thomas Imbrigiotta samples wells at the NAWC site in West Trenton, NJ
Installation of passive hydrogen samplers and microcosm samples in a multi-level packer well at the NAWC research site, West Trenton, NJ. Credit: Daniel J. Goode, USGS.

What led you to decide to become an Emeritus?

One of the main reasons I became an Emeritus was to complete a number of publications that I was working on at the time of my retirement. The main one was a USGS Techniques and Methods Report 1-D8 that defines USGS protocols for use of passive samplers in groundwater wells. I am happy to say that this report was published in April 2020. I am also working on finishing a couple of reports on the groundwater chemistry of the chlorinated solvents and PFAS compounds at the NAWC site for the Navy.

What exciting research or service activities are you currently working on, and what are you planning for the near future?

I have been advising and reviewing proposal submissions by other NJWSC hydrologists to get funding to investigate the use of passive samplers to collect samples for PFASs. A project in the NJWSC was funded by the Next Generation Water Observing Systems (NGWOS) program to look at this question, so I have been consulting on how that study should be set up to get valid comparable results between RCDM samplers, dual membrane samplers, and purge samples.

What do you enjoy and appreciate the most about being an Emeritus?

Not having to worry about finding funding for myself! In the water science centers, we have always had to scramble to fund ourselves each year since most of our funding is not direct from the USGS but comes mostly from other cooperators. It’s a great feeling to be able to just work on finishing papers and reports without having to justify your time.

What type of mentoring or outreach activities do you currently undertake as an Emeritus?

Over the past couple of years, I mentored several hydrologists from the NJ, NY, and NV Water Science Centers on how to build the RCDM samplers and other passive samplers for use on their projects. Outside of USGS, I am proudest of my work with a temporary shelter for abused and runaway teenagers called Anchor House in Trenton, NJ. I have been involved with this charity for 24 years now. For the past three years, I’ve been a member of the organizing committee of the Ride for Runaways, their annual 500-mile one-week bike ride, that raises about $500,000 each year to support the work of Anchor House. I actually rode my bike for 15 years and have done support for nine other years, which includes setting up food and water stations 20 miles apart each day and helping rescue bikers with breakdowns or injuries. For the first time, because of the coronavirus, this year’s ride will be a virtual experience, so instead of transporting 200 bicyclists 500 miles away from Trenton (e.g., Niagara Falls, Western Pennsylvania, Natural Bridge in Virginia) and having them ride back, people will be riding around where they live and will keep track of their mileage on a website, all while trying to get donations from people to support their effort.  

Which one thing do you wish you would done differently during your career?

I wish I had been able to manage my time more efficiently and finished more reports and papers in a timely fashion. It always seemed like the funding ran out before all the papers on the project could get written and published.

Have you had any great career mentors, and if so, what made them great?

I have been fortunate to have many great career mentors. Mark Ayers helped me get hired in Indiana and taught me the basics of field work. Also in Indiana, my first supervisors Steve Ragone and Bill Wilber got me the training in groundwater hydrology that I’ve use throughout my career. Pat Leahy, Herb Buxton, and Otto Zapecza convinced me to move to New Jersey and allowed me to work on research projects that were not only scientifically interesting but essentially made my career. What made them great mentors was they all gave me a little guidance and then let me have the freedom to go learn and try things on my own, reeling me back in when they sensed I was getting off track. I appreciated them all for both of those characteristics.

The Arenal Volcano in Costa Rica
View of the Arenal Volcano from our hotel room just outside the Arenal Volcano National Park, north-central Costa Rica. Credit: Jeanne M. Imbrigiotta. 

Where did you travel last, domestically or internationally?

Aside from visiting our sons in Virginia, our last big trip was in September/October 2019 to Vermont where we combined visiting friends and seeing the autumn foliage with attending a NGWA conference on Fractured Rock Hydrology where I helped present a workshop on a downhole sampling device we developed at the NAWC research site for measuring desorption, adsorption, and biodegradation rates in fractured rock.

Our last international travel was a trip to Costa Rica in November in 2017. We got to visit an old bicycling friend who moved down there in retirement, had the Arenal volcano out our window at one hotel, and stayed in a tree house in the Monteverde rainforest. We saw all kinds of animals and vegetation we had never seen before. The most interesting thing was that one day on a hiking trip at a nature preserve, our guide abruptly told us to STOP, pointing out where a 10-foot swath of the ground ahead of us was moving – it was a large group of army ants! Needless to say, we took a different path!

What is one characteristic that you believe every good research scientist should possess?

Every good research scientist should be able to ask stupid questions! This is very important if another scientist is telling you something and you don’t understand what they are saying or don’t buy what they are saying. You have to be able to swallow your pride and ask them to explain. Only once you understand it can you move forward effectively. The ability to ask stupid questions has served me well over the years. It can keep you from wasting time, getting off track, or repeating other’s mistakes.

What advice would you give someone who is contemplating retirement and the life that follows?

Before you retire, make sure your situation is right financially, but also emotionally. Are you really ready to stop working on research that you spent the last 20 years working on? If you aren’t ready to do that, then consider becoming an Emeritus! I kind of look at becoming and Emeritus as a way of easing into my eventual real retirement. 

How are you spending your time during the pandemic?

During the pandemic, my wife and I have spent most of our time quarantined at home since we both have risk factors. Besides teleworking three afternoons per week, I’ve gotten some long overdue projects done around the house, planted our garden, and learned about ordering groceries online for curbside pickup a week in advance. Just recently, we did venture out for the first time in months to visit both of our sons in Virginia where our grandkids live. We visited our 2-, 4-, and 15-year-old grandchildren that live in Chesapeake. In Alexandria, we got to meet our newest grandson, Dylan, who was adopted around the end of May. He is a very cute growing boy!

Thomas Imbrigiotta addresses a GSA field trip workshop
GSA field trip workshop explaining vertical water chemistry differences in multi-level well zones at the NAWC research site, West Trenton, NJ. Credit: Daniel J. Goode, USGS. 

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