Learn the Following in This Free Webinar:

  • Tools to accurately quantify halorespiring bacteria and functional genes when using PlumeStop to treat chlorinated solvents in groundwater
  • How to conclusively demonstrate degradation of contaminants in soil and groundwater
  • Case study documenting remedy selection at a chlorinated solvent impacted site

Learn More

  • If you need assistance with a current project and would like to get a design and cost, please visit our Request a Design page.
  • To get in contact with a REGENESIS Technical Solutions Manager use our Contact Us form.

I saw the webinar with Matt Burns of WSP a couple months ago showing case studies on these products. Both of you mentioned the cost savings from using molecular tools to optimize performance. Do you have any information about the cost benefit that you could share?

Actually, this is something that Matt and I have been talking about. And hopefully, within the foreseeable future, we’re gonna be putting together a webinar talking about cost benefit analysis from using these tools and implementing it at your site. Hopefully, that can help you sell it to the end user and explain to them the value of it. So check back with us. We’re gonna put some information together. And you should see some emails about webinars and other things that will be happening on that very topic.

Can you explain a little about the QuantArray analysis? Do we use the same QuantArray for both chlorinated and petroleum sites?

So QuantArray is the same thing as what you’ve probably heard for the last 15 years, 20 years, qPCR. So it’s taking qPCR and doing it in a smaller volume. So qPCR is tried and true. We know it’s the best way to quantify our microbial targets at a site and get accurate concentration of these organisms and functional genes. And that’s really the key. We can get functional genes too with this. So with the QuantArray analysis, we can look at a lot of different pathways that we can be interested in and a lot of different microorganisms all in a single analysis because we’re using such small volumes. And we get independent numbers in little through holes that don’t interact with each other. So we can really count on these results to be very reliable quality data.

And so we have different QuantArrays that are designed, one, for chlorinated sites where we look at all the known pathways for reductive dechlorination, co-metabolism, and terminal electron processes that can be important for those sites. For petroleum sites, we have both aerobic and anaerobic genes that are on there. For a variety of petroleum contaminants from BTX to alkanes to PAHs. So there are two different QuantArrays that are available, and they would be specific to that contaminant of concern.

What stage of site design should we start using these molecular techniques? Only in the beginning of site design or can they be used throughout the process?

You know, really you can use them throughout the whole process. I would encourage you to be consistent in what you do with your monitoring. You can do the in situ microcosms like we showed here to help you evaluate treatment strategies. And then know which key processes and organisms are gonna be important. And then you can continue to monitor them throughout whatever your treatment strategy is. And that way, if you need to make optimizations or there needs to be changes in the amendment or a slight change at the site, you can make those very effectively by looking at those concentrations and combining it with your other data.

In the slide called MNA (control) units…” And I believe this was pretty early on, maybe 10 minutes into your presentation, the question is, “In the slide called MNA (control) units, how is the geochemical vial collected? Is it a Snap Sampler?”

It’s not a Snap Sampler. It’s just a vial that has a passive membrane on top. And we’ve tested this. And we get good exchange through that membrane. So you get equilibration of the water that’s originally in there, the Nanopure water that’s sent out in the vial with the site groundwater. And we can measure a lot of things from that vial looking at dissolved gases, anything that’s happening within that unit. If there’s changes in the geochemistry over time, we also see that in the vial, as well, but it’s a passive membrane on top of that.

What concentrations do you need to do CSIA? And what elements can you do CSIA on?

CSIA is most helpful… What we’ve found, especially for chlorinated compounds, there’s not really a good way because these compounds are used as electron acceptors by microorganisms. The contaminant concentration we can measure with CSIA, the values that we can get, are very low. It depends on the compounds. If you want to shoot us an email with which compound, we can give you the particular detection limit, but we’re talking ppb values there, so very low detection limits for those. So for chlorinated compounds, most any of the isomers that are out there are daughter products that are being formed. You can also use it for compounds like 1,4-Dioxane and some others. Some of the fractionation processes aren’t as well defined for those compounds, but it can be used for a pretty big variety.

Now, for petroleum hydrocarbons, the fractionation is a little less seen in some of those compounds. And so, stable-isotope probing is a better tool. And there’s a video on our website that talks about when to use CSIA and when to use stable-isotope probing. That might be helpful, if you’d like better information about that. But for petroleum hydrocarbons, I would probably recommend the stable-isotope probing.

What is the cost of the in situ microcosm study?

It varies depending on what test that we do inside. And we can, you know, make these different, depending on the questions we’re trying to answer, but typically each of those units from the whole package, buying the unit itself, all the analysis that goes into it, and a report telling us from the microbial perspective what we think is happening at the site. It’s around $1,000 to $1,500 per unit.

The in situ microcosm case study, in that case study presented, was the testing done before the initial injection or following the first and before the second?

It was before anything was done at the site. So this was the initial test to decide what injections were gonna be performed at the site.

In the slide called ‘microbial analysis, with the bar chart, what is the acronym SRB? And why was it only reported in that last sampling event?

We did sulfate-reducing bacteria is what that was for. And it was in the initial events when sulfate concentrations were higher. And what you saw in that slide is that sulfate-reducing bacteria were present at the site. And then once we saw… After that first injection, you saw sulfate concentrations, the sulfate itself, rapidly decrease, and we saw an increase in sulfate-reducing bacteria. And the reason we monitored that early on is we wanted to make sure that we were getting those sulfate chains to sulfide so we could get that iron sulfide formation.

Application of those baffled units looked very interesting. How was long-term monitoring done using those baffled units?

So typically we would use these for a short-term study. You would deploy them for 60 to 90 days in most cases. And we have done it for slightly longer. The only thing you’ve gotta worry about is if we do it for a longer period, we can’t add enough electron donor or acceptor to last for those long periods of time. So we might have to reload those. And so in that case, if you have to pull them out, it makes the baffles not effective, right? So we would have to, you know, only do one type of treatment being tested in a well. In that way, if we had to reload that treatment, we have done it where we’ve left them for 180 days at a sight to see what was gonna happen, but we had to reload additional electron donor at a middle point in that. So that kinda limits us in being able to test different remediation strategies. So the typical would be two to three units that are deployed in a well. Always have a control unit so we can benchmark what we’re seeing for comparison. And then the other one to two units in that well would be typically different treatment strategies. And they would be left for 60 to 90 days.

What is the typical scale of projects these products have been successfully used on?

Yeah, maybe they’re talking about the number of samples that are typically done at a site. So for the typical site, I would say the microbial characterization, you usually pick three to five representative samples. You want to collect in the source area. You want to collect down gradient. If it’s a large site, you might want to get a couple of additional cross-gradient samples, but get, kind of, a good distribution. The rule of thumb I use is if you see big changes in the geochemistry or if you see an order of magnitude change in your contaminant concentration, collect samples there. So hopefully, that’s what you’re talking about.

If you’re meaning how often are these applied, this is becoming more routine. We see this that the regulatory agencies are really accepting these tools as a third line of evidence. They’re really valuable in accepting these different treatment strategies and feeling like we’re doing a much better job of characterizing and understanding what we’re doing at the site. So these are more readily accepted on a larger scale by sites around the world. We’re seeing other countries performing this type of analysis, as well. U.S. is really the leader in this, that we now see this really branching out at sites all over the world.

I think you stated that only the parent product should be tested for fractionation. Was it CSIA? And is this due to the intermediate formation and destruction? Yet daughter products were discussed in the presentation.

So what I actually meant by that is I would recommend looking with CSIA of both the parent and daughter products, if you’re looking to prove degradation of the parent-daughter compound. But if you want to elucidate which pathway, it can be difficult to get that isotopic enrichment factor. So that’s what I was meaning there. If you’re trying to get that epsilon value where we plotted the slope of the line and we looked for that isotopic enrichment to tell us if it’s biotic or abiotic, you can do that for parent very easily, but it’s much more tricky for daughter products. So use CSIA for parents and daughter products both to indicate that degradation is occurring. But if you’re looking to elucidate the pathway of biotic versus abiotic, then only do that on the parent compounds.

How do you interpret bio or abiotic when your slope lies within the range of both epsilons for a particular compound?

Oh, that can be difficult. We didn’t see that in the case here. You would probably have to do additional testing. And if it actually lies… I don’t think I’ve ever seen where those biotic ranges overlap with the abiotic ranges, but if that were to happen, we’d have to look at other lines of evidence to see, do we have microorganisms there that are potentially available to do the degradation? If those are absent, then maybe, you know, look at, you know, what chemical geochemistry looks like at the site. You know, do we have magnetite or other compounds available that can do abiotic degradation? So take a comprehensive look at those multiple lines of evidence. And try to elucidate it a little better. And there can be times where you’ve got both degradation pathways that are occurring, but that other data would help you to figure that out.

Would high concentrations of aluminum,” and they say, “up to several percent, in saturated site soils cause a problem for TCE degradation?

For aluminum, I’m not sure. I haven’t seen anything in literature that would talk about that in particular. If you want to email me directly about that after this webinar, we can do some lit searches. And we can get back with you to let you know about that in particular, but I don’t think I’ve seen anything in literature that talks about that interfering with TCE degradation.

Video Transcription

Dane: Hello and welcome, everyone. My name is Dane Menke. I am the digital marketing manager here at REGENESIS and Land Science. Before we get started, I have just a few administrative items to cover. Since we’re trying to keep this under an hour, today’s presentation will be conducted with the audience audio settings on mute. This will minimize unwanted background noise from the large number of participants joining us today. If the webinar or audio quality degrades, please disconnect and repeat the original login steps to rejoin the webcast.

If you have a question, we encourage you to ask it using the question feature located on the webinar panel. We’ll collect your questions and do our best to answer them at the end of the presentation. If we don’t address your question within the time permitting, we’ll make an effort to follow up with you after the webinar. We are recording this webinar, and a link to the recording will be emailed to you once it is available. In order to continue to sponsor events that are of value and worthy of your time, we will be sending out a brief survey following the webinar to get your feedback.

Today’s presentation will focus on how to select and use molecular biological tools. With that, I’d like to introduce our presenter for today. We are pleased to have with us, Dora Taggart, president of Microbial Insights. Dora received a biomedical engineering from Vanderbilt University, and is focused on the optimization and implementation of molecular tools for environmental remediation, microbiologically-influenced corrosion, and microbial source tracking. Since joining Microbial Insights in 2001, she has developed and commercialized over 60 different nucleic acid-based analyses. Under her direction, Microbial Insights has become a world-wide provider of molecular tools for leading consulting firms, government agencies, and academia. All right, that concludes our introduction. So now, I’ll hand things over to Dora to get us started.

Dora: All right. Thank you very much, Dane, for that kind introduction. And thank you, everyone, for taking time out of your busy schedules to attend the webinar today. As Dane mentioned, my name is Dora Taggart, and I’m the President of Microbial Insights. And today, I’m going to be talking to you about ways that we can use molecular tools to help you generate actionable data that you need for site assessment.

Before we get started, let me just briefly introduce Microbial Insights to make sure we’re on the same page. We’re a biotechnology lab that was formed in 1992 by research from Dr. David White. Our primary purpose is to progress a legacy of innovation and integrity in microbial analytics with comprehensive customer care so we can deliver actionable data that you need to reach your goal. Microbial Insights has multiple locations around the world that we can use to receive your samples, so no matter where your project is, one of our labs is usually within easy reach.

We’ve been operating for over 26 years, and we’re the leading provider in molecular services around the world. And during this time, we have accumulated a lot of microbial data. Our database that we have for microbial processes is comprised of more than 30,000 samples from all 50 states, more than 35 countries on 6 different continents. Microbial Insights is really a leader in these tools, and we can use this database to help us really put into context what does it mean when we have a certain concentration of a microorganism or a functional gene, what does that mean for our process? How do we take action on that result for our sites? And that’s some of what we’re gonna talk about in the presentation today.

Microbial Insights has worked with REGENESIS for more than 20 years looking at how our services can be compatible with the many wonderful products that they offer. As many of you know, REGENESIS has a large variety of products. Just a few of them are shown here that can be applied to your site to help you really reach your goal. So whether you’re adding HRC or 3DMe to try to simulate reductive de-chlorination or maybe you’re adding that BDI culture to enhance your Dehalococcoides populations at a site. We have tests that we can do analytically looking at those microbial populations to help you confirm that you’re getting good use of these products in the field, that you’re getting good distribution, that things are performing as you want.