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Groundwater Contamination with Dr Danielle Toase and Dr Lange Jorstad
338 Plays10 months ago
In this episode, Shonelle chats with two special guests, Dr Danielle Toase and Dr Lange Jorstad.
Danielle Toase is an Environmental Manager, with a BSc in environmental science and PhD in environmental geochemistry. She has over 10 years experience across the fields of environmental research, regulation, remediation contracting, consulting and corporate environmental management.
Danielle has worked at multiple complex PFAS contamination since 2016, particularly at aviation sites or sites where multiple sources of PFAS exist. Her interests surround PFAS fingerprinting, source delineation, remediation technologies and the circular economy. Danielle is also an active member of ALGA, having recently been appointed to the Board of Directors and is an honorary research associate at Macquarie University.
Lange Jorstad is a Principal Hydrogeologist at Geosyntec Consultants, with a BSc in geological sciences from the University of California, Santa Barbara, and a PhD in contaminant hydrogeology from UNSW. He has over 20 years’ experience as a consulting hydrogeologist, specialising in contaminant fate and transport and environmental geochemistry.
Lange is a NSW EPA accredited Site Auditor and Certified Environmental Practitioner – Site Contamination Specialist, is an active member of the ALGA groundwater fate and transport special interest group, and provides university lectures on groundwater, contamination and sustainable remediation. He has provided consulting and auditing services for PFAS-contaminated properties for government and industry clients since 2015, including local development sites, fuel terminals, landfills, and airports.
You’ll hear how they got started in their respective fields, including Danielle’s PhD studies in Antarctica focused on chemical fixation of heavy metals in legacy landfills using orthophosphate and silica reagents.
Lange shares advice for local councils investigating landfills as a contamination source, and the evolution of groundwater remediation from pump and treat to in situ technologies, and Danielle discusses the purpose of PFAS fingerprinting and why it’s important especially in complex hydrogeology and sites with multiple potential sources of PFAS.
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Transcript
Podcast Introduction
00:00:01
Speaker
Welcome to Contamination Station, safer environment together, a New South Wales EPA funded podcast. In these episodes, you'll hear from those working to implement contaminated land policies and procedures at the local level by sharing our stories, frustrations, wins and losses. Our aim is for this podcast to become a repository of information that will support those currently working to combat contaminated land and for those yet to come.
Meet the Experts: Dr. Danielle Toaz & Dr. Lang Juhlstad
00:00:30
Speaker
Today's episode is a conversation with two very special guests, Dr. Danielle Toaz and Dr. Lang Juhlstad. Danielle is an environmental manager with a Bachelor of Science in environmental science and a PhD in environmental geochemistry.
00:00:45
Speaker
He has over 10 years experience across the fields of environmental research, regulation, remediation, contracting, consulting and corporate environmental management. Danielle has worked at multiple complex PFAS contamination sites since 2016, particularly at aviation sites or sites where multiple sources of PFAS exist. Her interests are PFAS fingerprinting, source delineation, remediation technologies and the circular economy.
00:01:12
Speaker
Danielle is also an active member of ALGA, having recently been appointed to the board of directors and is an honorary research associate at Macquarie University. Lang is a principal hydrogeologist at Geosyntech Consultants with a Bachelor of Science in Geological Sciences from the University of California, Nanda Barbara, and a PhD in Contamined Hydrology from UNSW.
00:01:34
Speaker
He has over 20 years experience as a consulting hydrogeologist, specialising in contaminant fate and transport and environmental geochemistry. Lang is a NSW EPA accredited site auditor and a certified environmental practitioner, like contamination specialist. He's also
00:01:49
Speaker
He is also an active member of ALGA Groundwater Fate and Transport Special Interest Group and provides university lectures on groundwater contamination, sustainable remediation. He has provided consulting and auditing services for PFAS, contaminated properties for government and industry clients since 2015, including local development sites, fuel terminals, landfills and airports.
00:02:13
Speaker
The views and opinions expressed in this podcast are solely those of the host and the guest as individuals, and do not necessarily reflect those of the New South Wales EPA or any other organisation.
Motivations in Geochemistry and Hydrogeology
00:02:25
Speaker
Hi, and welcome to this episode of Contamination Station, an EPA funded podcast. I'm your host, Chanel Gleason-Willi, and our guests today are Dr. Danielle Toaz and Dr. Lang Jostad. Hi, Danielle. Hi, Lang. Thanks for your time. Hi, Chanel. Thanks for having us.
00:02:41
Speaker
Yeah, thanks for the invitation, Shlal. It is really great to have you both here. A different sort of conversation to what we normally have. So our first question today is that I would like to talk about your studies at the start of your careers. So you've both studied extensively with Yu-Lang holding a PhD in contaminant hydrogeology and Danielle with a PhD in environmental geochemistry.
00:03:06
Speaker
So what was it that appealed to both of you? Basically, what made you want to spend a good seven to nine years in that field of study? Yeah, so to be completely honest, I actually kind of fell into my PhD.
Danielle's Antarctic PhD Adventure
00:03:19
Speaker
So I graduated during the GFC and there were very few jobs around at that time. But I got lucky and I managed to score a job basically being the equivalent of sort of healthy Harold, but for sustainability and environment. So I used to
00:03:34
Speaker
go around to primary schools and try to teach the kiddies about environmental and sustainability issues. And that role was really fun, although children can be fairly brutal at times. But I knew I sort of couldn't stay in it long term. Had a few of those roles, actually. And through a sheer stroke of luck, the opportunity to go to Antarctica and do a PhD came up. And there's a bit of a free spirit with nothing tying me down in those days. I just couldn't really say no. And the rest is history.
00:04:02
Speaker
So what was the focus of your PhD? It's always so exciting to hear that people, you know, go to Antarctica to study. I have been there myself and it is amazing. So tell me about your PhD. What did you do for it? So my PhD was actually focused on chemical fixation of heavy metals in legacy landfill fusing orthophosphate and silica reagents. So there was a particular emphasis on reaction kinetics and how temperature influences the performance of chemical fixation in those remote cold environments.
00:04:30
Speaker
And I was really lucky with that opportunity because I had an exceptional PhD supervisor and also my honours supervisor was similarly really supportive. And so those opportunities and experiences were really kind of instrumental in developing my technical skills quite early in my career. So was your study focused around the peninsula or was it more on the islands where there was the old ceiling and whaling colonies?
00:04:55
Speaker
So my project site was actually Wilkes Station, which was a station that was sort of abandoned sometime around the 60s, I believe. So yeah, it was an old legacy landfill on the peninsula. Very interesting.
Lang's Journey from Geology to Hydrogeology
00:05:08
Speaker
And Lang, what was the focus of your PhD?
00:05:10
Speaker
Not nearly as exotic a locale as Antarctica. My PhD was at an old council tip, effectively. It should become a golf course over the years, just south of UNSW. And I was looking at the flux of contamination, essentially, through the aquifer between the landfill and adjacent pond.
00:05:31
Speaker
and the variability sort of on small spatial and temporal scales of that contaminant transport between the landfill and the pond and the processes that sort of control contaminant transport in that setting. I guess similar to Danielle, I
00:05:52
Speaker
I sort of fell into the PhD track a little bit on the back of my initial work as a consultant. So I did my geology degree in California. And from our undergraduate course, there was
00:06:11
Speaker
really sort of two tracks that people took. They either went into resources. So a lot of people in my apartment went into jobs with oil and gas companies or mining companies. And then the other cohort sort of went into the environmental track. And that was, I guess, more aligned with my interests at the time. So I worked as a consultant for three years in California doing quite interesting work. I got quite lucky with the consultancy that owns
00:06:41
Speaker
That was my first job and they really had some big interesting contaminated site work and a lot of it was groundwater focused. I guess that's what really piqued my interest. I didn't have a strong focus initially into the specialising within the environmental industry when I started that job.
00:07:05
Speaker
over the three years, it was clear that that, to me, was really the most interesting part, how contaminants enter groundwater, how they move with groundwater, and how you get them out of groundwater.
00:07:19
Speaker
So we decided, my wife, girlfriend at the time, and I decided that we wanted to have a little life adventure and move overseas. And I knew that the easiest way for me to do that and have a visa and a reason to be there was going to be to go back and do my postgraduate work. So I started
00:07:38
Speaker
with a master's degree track at UNSW and then my supervisor with a little bit of poking and broadening said, you really should turn this into a PhD. So that was sort of how I wound up on that track.
00:07:53
Speaker
Hmm.
Advancements in Hydrogeology and Remediation
00:07:54
Speaker
So with doing post-grad work and then I guess also working in the industry, you must have seen some really interesting and exciting advancements in the fields of environmental geochemistry or hydrogeology. So can you tell me a bit about maybe some of the changes or advancements that you've seen over the years? Sure. So my, I mean, my focus has largely been in contaminant transport. So, you know, hydrogeology sort of covers that.
00:08:23
Speaker
a broad range of topics. There's water supply and security and various other things. I guess what has really drawn me to the contamination side is the advancements in the understanding of the physical, chemical, and biological processes that all affect the movement of a contaminant with groundwater through an aquifer.
00:08:52
Speaker
what causes it to attenuate, what may exacerbate the transport of certain contaminants, what contributes to exposure pathways, and in particular, what can you do to clean up contaminated groundwater
00:09:12
Speaker
in various different settings. And I think that is probably the greatest area of advancement over the past 20 to 30 years in our industry.
00:09:22
Speaker
moving from sort of these old paradigms of the only way to treat groundwater is to pump it out of the ground and put it through a treatment plant, dispose of it in some ways. And the technology and the techniques have come a long way towards even more sustainable approaches, in situ approaches, using the biology of the aquifers to actually
00:09:50
Speaker
enhanced degradation of contaminants in the ground. So that, you know, for me, I find that, you know, really interesting and engaging. That sort of driven, you know, it's been the common thread of my career, and that's really my core interest.
00:10:05
Speaker
Yeah, sure. We will talk a bit more about that later on to have some questions to grill you with. But let's just take a step, a slight step back at the moment. I'm really interested to know that as an auditor, but with a speciality in hydrogeology, do you limit your, I guess your auditing practice to that field or are you able to operate more broadly?
00:10:30
Speaker
I operate more broadly. I audit across all types of scenarios. The requirement for audits is often linked to land development, and that means it can be anything from a
00:10:45
Speaker
a single residential lot that just has a bit of poor quality fill on it to more complex industrial facilities or airports. So it kind of runs the gamut. I don't limit my auditing to my technical background. I do get involved in audits or have the opportunity to get involved in certain audits that have a strong
00:11:12
Speaker
groundwater focus by virtue of having that technical background. So the auditors in the scheme come from a diverse range of backgrounds. Some are Jacksonville trades, some are risk assessors. I think all auditors will tend to have a reputation for
00:11:35
Speaker
what they're good at, if you know what I mean. So when you have a project that's sort of strongly focused on, say, a groundwater contamination issue, it makes it a little bit easier to have an auditor that has a strong understanding of the fundamentals and is able to answer questions and make decisions based on their
00:11:58
Speaker
on their own expertise, I suppose, rather than being wholly reliant on getting outside expertise to make those decisions. Yeah, yep. And Danielle, you've worked a lot with Lang over the years. What form does this partnership usually take? And how do you find it works best for an environmental manager or consultant to work with an auditor?
00:12:23
Speaker
Yeah, sure. I actually don't get to work with Lang as much as I'd probably like to. And I'm not just saying that because he's in the room, but I do believe he has to be one of the most talented and well-respected practitioners we have in this country. So I'm always feeling lucky when I get a chance to work with Lang. But I guess in terms of that partnership, I have learned a few things that may hopefully benefit others.
00:12:45
Speaker
Firstly, I would say to get the auditor involved as early in the process as you can. We often get auditors involved even when we don't have to or there's no regulatory requirement to do so, particularly in environments where there are sensitive stakeholder relationships.
00:13:03
Speaker
Really for a project to be successful, you need to build trust and for all stakeholders to feel heard and comfortable to the best extent possible. And appointing an auditor can be one way of providing that comfort because it can provide an additional layer of rigor to the investigation process that I think can be beneficial.
00:13:22
Speaker
But when thinking of how that partnership looks, auditors also have to have boundaries and they have to sort of have that safe distance to retain impartiality. And that's got to be respected by all parties for everyone's benefit, including the integrity of the site audit scheme. And so one of the things I really enjoy about working with Lang is that he will tell me things I may not want to hear, but he has a great way of communicating and helping me to understand the situation.
00:13:45
Speaker
But I think the other important piece of that puzzle is pairing the right consultant with the right auditor. So as Lang mentioned, you know, every consultant has a strong set of skills. And so really like finding that right balance for a project, I think is critical to the success. So recently I was managing
00:14:02
Speaker
quite a complex series of investigations that needed a consultant with really deep technical expertise and similar expectations in terms of quality. And I was lucky to find that and then paired with Lang we ended up with a really great project team. Sometimes you don't need a consultant with that level of technical depth and you just need them to be adaptable and responsive.
00:14:21
Speaker
And I'm conscious of the fact that on some projects I can afford to be a really relaxed and easier client to deal with. And then on other projects where the stakes are high or the risks are really high, I can probably be a bit of a nightmare and quite difficult to tolerate because in those situations they have to have a really high demand on quality because the work we put forward is not only a reflection on me or my consultants, but also like it's critical if we're trying to build trust with a complex set of stakeholders and it also reflects
00:14:50
Speaker
on my organization and my colleagues who are all sort of driven by trying to do the right thing to the best of our abilities. So finding that right cultural mix on a project, I think is almost equally important. Yeah. And Lang, do you, I'm assuming you agree with all of that. It was interesting to hear Danielle say that she can wear different types of hats depending on the type of project. Are you able to do that as an auditor as well? Or is it really very much you have to come in and be very strict for regardless of what the project is?
00:15:19
Speaker
Well, the audit scheme has a very specific set of rules. So you have to maintain your independence. You have to comply with a whole set of criteria and guidelines for the side auditor scheme. That being the baseline, every project is a relationship between people really. So, you know, the ability to interact with people on different technical levels, you know, some clients like Danielle are very technically savvy.
00:15:47
Speaker
and have a really strong understanding of all the environmental issues that are subject of the audit. Other clients have no idea. It's not their area of specialty. There may be developers, really all they want is to get your site audit statement and move on and they don't want to know about all the details.
00:16:11
Speaker
you do have to be adaptable to all those scenarios as an auditor. You don't get the luxury of necessarily getting to cherry pick all of your clients and your projects and your audits. There's an expectation as accredited auditors that we are available to the market. And
00:16:31
Speaker
people who need audits, you're not supposed to be turning people away necessarily because you don't want to work with them. Everyone who has a requirement needs to be able to access an auditor. And the relationship between the consultant and the auditor is an important one. Is it a consultant who will engage with you openly or are they
00:17:00
Speaker
Do you get the feeling that they're just forever trying to just sweep past the line by the narrowest of margins? All these things happen. It runs the gamut. So not only do you have to be technically proficient, but you have to be able to sort of read the review, I suppose, an auditor and figure out what level of engagement is required to get a project across the line.
00:17:28
Speaker
whilst maintaining the independence and all the rest of the rules of the side auditor scheme. So with those, a lot of these projects that you have worked on both together and obviously separately as well, a lot of them have to do with PFAS.
Understanding Geology in PFAS Investigations
00:17:42
Speaker
And I know that you're both very skilled in the area of PFAS investigation or remediation. So when dealing with different contaminants such as PFAS,
00:17:54
Speaker
It is extremely important to understand your geology and hydrogeology to prevent such things as potentially contaminated groundwater sources by your investigations. So can you explain what's important to understand when you're doing your investigations and doing things like drilling, screening and sampling for a groundwater well in these situations?
00:18:15
Speaker
Sure. This is an issue that isn't necessarily limited to PFAS. In any scenario where you're dealing with contaminated groundwater, there's always a risk of making the issue worse by virtue of the way that you investigate it. There are some classic examples in the industry, and I won't name any of them in a specific way, of contamination issues that started as, say, a relatively shallow groundwater impact issue.
00:18:45
Speaker
that ended up as a very deep and large groundwater issue. Part of the suspected reason for that was that a shallow confining layer had a whole bunch of holes punched in it during the investigation phase that allowed this hydraulic connection between the shallower zones and the deeper zones that didn't necessarily exist. So it is
00:19:12
Speaker
very important in certain settings that if you suspect that there are multiple aquifer zones or multiple water bearing zones present, that if you're going to look at the deeper ones, you have to quite carefully
00:19:32
Speaker
case off the shallower zone. So there are drilling techniques where you can drill down to that shallowest confining layer that's still chasing, that hydraulically separates off that shallow contaminated layer before you drill deeper. But
00:19:50
Speaker
Depending on the contaminant type, it can be quite risky, really. If you're close to a source area, for example, on those really high concentrations, you are sometimes better off starting from the outside and working in rather than trying to go deep right beneath the source and potentially turn a small issue into a much bigger issue.
00:20:20
Speaker
And which contaminants in particular would you say you'd have to be more careful of in those situations?
00:20:25
Speaker
Well, the classic one is the class of contaminants called D-napples, and that stands for dense non-aqueous phase liquids. Essentially, it just means liquid chemical contaminants that are not water, denser than water. In their pure form, they're sort of oily substances or tar-like substances. Fluorinated solvents is a classic example. And when these are released,
00:20:52
Speaker
In their pure form, because they're denser than water, they tend to just sink through an aquifer and they will pool on low permeability layers, so confining layers when they reach the subsurface.
00:21:08
Speaker
And they will sit there, then slowly dissolving from where they've come to rest, if you will, in the subsurface. The problem is that if you punch a hole in that confining layer that they've come to rest on, they will follow the path of least resistance and continue down through that hole and continue to sink. So typically the highest risk in terms of protection of deeper groundwater zones is when you're dealing with
00:21:38
Speaker
Dean Apples and suspect that you may actually have to pure-phase Dean Apples presently.
00:21:44
Speaker
The hydrogeologic setting may make it different sometimes. The deeper aquifers have a higher hydraulic pressure, so that even if you were to create a connection between the two zones, if you have an upward hydraulic gradient or a higher pressure in that deeper aquifer, that will tend to prevent dissolved contaminants moving downwards.
00:22:11
Speaker
You don't often know that in advance. You're starting with a blank slate, first principles of hypergeology, and so you always have to approach every situation like that with a lot of care. What sorts of industries would you expect to see Dean Apples as a contaminant source?
00:22:31
Speaker
Well, chemical manufacturers and anyone who uses those chemicals, there are probably the biggest Dean Apple sites that are typically associated with the manufacturers of those chemicals that have releases. Gas work sites, the tarry waste from gas work sites, that's a Dean Apple and it's very common to have tar releases from gas work sites.
00:23:01
Speaker
When I started my career, I was doing a lot of work in Silicon Valley south of San Francisco. There's a lot of computer manufacturing, microchip manufacturing in the area, and they're not producers of these chemicals, but they are high-volume users of the chemicals. They're sort of used in the electronics manufacturing process.
00:23:23
Speaker
And some of those sites, we sort of herald the technological advances that have come out of Silicon Valley. It certainly had an environmental legacy in some very large Dean Apple releases throughout South San Francisco. And that's much more recent than what we see here in Australia at say, Gasworks sites. Am I correct in saying that?
00:23:50
Speaker
Yeah, and I guess there are a lot of, if you look at the history of contamination, a lot of the sites we deal with started decades before people had an awareness of
00:24:06
Speaker
a release of contamination to the environment or that the activities that they were doing might have a detrimental effect on the environment. It was just a case of, hey, these are the products that we use in this manufacturing process, and if we have to dispose of them, well, they go down the drain, that sort of thing.
00:24:29
Speaker
the electronics manufacturing industry, it would be fair to say that that was recent enough that maybe they should have known better. And there's various reasons why these chemicals that should be sitting inside a factory end up in the ground and in groundwater. But
00:24:50
Speaker
I guess there's been a lot of awareness, and some of that is basically from hard lessons learned by industry, I suppose, having paid for some very costly cleanups that brought into the millions of dollars. But the environmental management of modern manufacturing processes tends to be to a much higher standard in terms of preventing contamination occurring in the first place.
00:25:18
Speaker
And Danielle, you've worked with PFAS
PFAS Fingerprinting and Liability
00:25:20
Speaker
a lot. Can you tell me more about your work in PFAS fingerprinting and how will this help us understand PFAS better?
00:25:28
Speaker
Yeah, sure. So the geochemist in me loves and sees the value in PFAS fingerprinting, but it's probably important to acknowledge that it may not be always required at every site or the depth of fingerprinting required will certainly almost vary. But I have a bit of an attraction to geographically constrained sites with complex hydrogeology and sites where there are multiple potential sources of PFAS in very close proximity.
00:25:54
Speaker
And then at those sites, the challenge really becomes centered around understanding who is responsible for what PFAS, and then the subsequent need becomes determining how to distribute responsibility and split the bill for mediation between different organizations.
00:26:09
Speaker
So PFAS fingerprinting when done correctly provides one of the important lines of evidence that I think should be considered when trying to tackle these sorts of challenges. And then beyond the investigation phase, understanding the signature of PFAS in a given environmental matrix can also be very valuable during remediation.
00:26:27
Speaker
particularly in say a water treatment situation where you may need to understand what compounds are likely to break through an absorption system first or in a soil remediation project using a technology such as soil washing. You might find that some PFAS compounds are easier to mobilize and remove than others.
00:26:44
Speaker
And depending on what your remediation goals are, these sorts of things can really make or break a project. But I think your question is really well timed because as an industry, I think we are starting to sort of move away from pay fast absolutism towards sort of proportionality. And at some sites,
00:27:02
Speaker
Geochemistry and PFAS fingerprinting can play a vital role in that discussion because it provides us with the ability to ground discussions about proportional risk and liability and splitting the bill in terms of proportional contribution and how you distinguish who is responsible for what.
00:27:18
Speaker
And that is one of the spaces that I really enjoy operating in because a lot of complex sites get held up at that point. And if you can find a way to move past that barrier by reaching a fair outcome for all parties, then you can progress those projects to a point where we're able to sort of focus our attention towards taking meaningful action and hopefully actually achieving a positive environmental outcome.
00:27:42
Speaker
So what key indicators do you look for? This is a very new area for me. I don't really understand it very well at all. But to be able to apportion liability, how do you differentiate company A's PFAS from company B's PFAS?
00:27:58
Speaker
Yeah, so it will vary across different sites and there are other lines of evidence you really need to pull in. So like groundwater flow direction will be a really important line of evidence in that sort of holistic understanding of proportional responsibility. But there's a lot of information that you can gather back in the sort of preliminary site investigation stage around
00:28:18
Speaker
what products we used at a particular site, maybe if there were any environmental incidences such as a loss of containment or a spill. And they give you really important clues in terms of the source. And so, firefighting foam is a really good example because often what you can find is that different organizations will use different firefighting foams and some organizations have quite good records and inventories around what foams were used when.
00:28:42
Speaker
And you can use advanced analytical techniques to really classify and characterize those foams well. And so what you might find is that some foams have a really strong signature for fluorotelamisulfonates and perfluoroalkyl carboxylic acid, where others will be really dominant in the sulfonic acids and the sulfonic acid precursors, such as your sulfonamides. And so
00:29:05
Speaker
looking at what products we use by who and where can actually be really pivotal, because you can have conversations around things like, well, I never use that particular foam, so we don't have a source of PFOS at our site, our primary indicator contaminates PFOA. And so it's using analytical technologies along with databases of product use, along with other lines of evidence such as the hydrogeology and groundwater flow to sort of pull that together holistically and sort of understand the issue more comprehensively.
00:29:35
Speaker
Thank you so much for that. That really explains it very well. I understand that a bit better now, which is really good. So we did discuss earlier on Lang about your background in waste facilities and your PhD, looking at legacy landfills.
00:29:54
Speaker
So something I've come across a fair bit is that regional councils often need to deal with old poorly managed waste facilities that potentially or actually have leachate issues or disused very old tip sites which were not properly decommissioned. So if you were asked to provide advice for regional council, where would you start with your investigations?
00:30:16
Speaker
Sure. Now this is a contamination source near and dear to my heart. I haven't spent a lot of time during my PhD looking closely at landfills subsequently in my professional practice. Landfills are tricky in that for various reasons. They're in the contaminated land industry. They're considered a fairly
00:30:36
Speaker
mature and well understood contamination source, but they sort of continue to surprise us. A lot of landfills and particularly sort of, you know, older tips that were, you know, operated in the 60s and 70s, it was very common throughout all counties.
00:30:53
Speaker
typically weren't designed with liners, leachate collection systems, landfill gas collection systems. Often they started as maybe a quarry. There was just a hole in the ground that was convenient to fill up with waste.
00:31:11
Speaker
And so everything that is in that landfill waste ends up coming out as degrades in the form of landfill leachate and the generation of landfill gas for the degradation of the organics.
00:31:27
Speaker
One of the problems in approaching these old legacy landfills, and especially old counts of tips, is that they're quite large sources. They can be very diverse. I mean, you can imagine anything and everything ended up in a landfill. So we often think about certain indicator parameters, landfill leachate. There tends to be a lot of ammonia. There tends to be a high salt organic carbon load.
00:31:55
Speaker
But you could have the full gamut of contaminants in a landfill. There's patrolling hydrocarbons, there could be chlorinated solvents, there could be metals, there could be pesticides. And most recently, there tends to be a lot of PFAS that was broadly used in a lot of consumer products. Those products end up in the landfill.
00:32:16
Speaker
that piece asks, just like all the rest of the contaminants leeches out. So how do you deal with them? A lot of, particularly regional councils, they're not exactly flush with money to go do extensive investigation of all these legacy landfill sites.
00:32:34
Speaker
My recommendation is always to start with the end in mind. So consider where the likely risks are, the highest risks. You can start with a conceptual idea of
00:32:50
Speaker
a hydrogeological setting, which way is groundwater flowing? If there's gas being generated, are there any structures in proximity to that old landfill? Identify those really high-risk exposure pathways and focus your efforts there. You'll never 100% characterize what's in a landfill, and it probably is a bit of a waste to try to do that.
00:33:20
Speaker
you're much better off looking at the emissions from the landfill and then in that regard really focusing on the ones that may be problematic, you know, landfill gas poses an acute risk, an explosive risk of
00:33:35
Speaker
methane accumulates within a structure. So that's probably your highest immediate risk to health. And then look at the potential impacts to groundwater resources from lead shade discharging from the landfill into a groundwater system.
00:33:56
Speaker
you know, where's that groundwater going? Is it issuing into a lake? Does it come out of the river? Are there water supply wells that are gradient? So my advice really for a council of finite means to undertake these investigations is to
00:34:14
Speaker
try to work out where the highest risks are likely to present themselves and really focus on those. And then you can make decisions. Sometimes you do just have to do the hard work and put in mitigation measures, interception trenches, gas collection systems. If there's a high enough risk, you will have to do that to mitigate the risks.
00:34:40
Speaker
But to make the best value of limited funding to investigate these old sites, we'll look at the riskiest pathways first.
00:34:50
Speaker
So I guess this also brings me to remediation and remediation of groundwater, as we mentioned earlier as well, has moved a long way over the last 15 years from the pump and treat to in-situ technologies.
Innovations in Groundwater Remediation
00:35:05
Speaker
So you mentioned that you've come across and used quite a lot of these. Can you tell me about your, I guess your experience with how successful they've been and the progress over the last 15, 20 years?
00:35:18
Speaker
In the good old days or the bad old days, groundwater remediation basically started as pump and treat systems. So you pumped groundwater out the ground, you sent it to a big engineered treatment plant, and that was the way that you got contamination out of the groundwater. And what the industry found over the years is that, A, it's very energy intensive, B, it's quite expensive wage, treat contaminated groundwater, and C, you get to a point of diminishing returns.
00:35:45
Speaker
beyond which you get a asymptotic level of contaminant removal using these techniques. And the industry over probably the last 15 to 20 years, looking at different drivers, it's not always very convenient to set up a water treatment plant on some people's facilities.
00:36:12
Speaker
And people learned that different classes of contaminants can be degraded in the ground, either chemically by injection of chemical amendments, or the area that is probably of greatest interest to me is using the local biology to degrade contaminants, enhanced bioremediation. And this is an area that Geosynthetic has put a lot of internal research and development into, and we see a lot of application, growing application in the industry.
00:36:42
Speaker
I would say in Australia, there's always been this perception that from a contaminated land remediation perspective that Australia may have lagged behind, say, North America or Europe by, I would say, 10 years in the progress of some of these technologies. Some of that is just due to the differences in the regulatory schemes. And I think
00:37:09
Speaker
when some of these in situ remediation techniques were first being adopted in Australia. I think there was a little bit of a negative experience with some of these because conceptually, it seems quite simple that we're going to inject a chemical into the ground, that chemicals could interact with contaminants and break them down. Actually,
00:37:35
Speaker
performing that task is quite complicated. And I think it wasn't given its due regard by some of the early practitioners. And so there's actually some, you know, lots of examples of failed in situ remediation projects because they just weren't performed by people who had the right experience to be performing them. And I think that made the industry a little bit gun shy for a while.
00:38:02
Speaker
to adopt these techniques and it gets in Australia, it's now sort of recovering from that initial bad experience perhaps as the skillset and the competency and the contaminated land industry has ramped up and you start to see some real success stories. But they're much more... I do a lecture on sustainable remediation at UTS, a lot of these techniques
00:38:31
Speaker
use a lot less energy, a lot less water. They don't involve truck movements. They're not generating tons of carbon dioxide to clean up grams of contaminant, that sort of thing. And as a society and certainly in the
00:38:50
Speaker
corporate world sustainability has become a really important metric. And so, you know, cleaning up a contaminant is always viewed as positive, but as people started to calculate how much waste are you generating? How much resource are you consuming to actually clean up that contaminant? Are you actually doing more harm than good?
00:39:15
Speaker
depending on the technique that you're using to clean up what in some cases amounts to grams of contaminant in the environment. And that's one of the benefit of these in situ techniques is that they are less resource intensive and they're less impacting on the surrounding communities generally and they achieve the same outcome. And so if you can achieve the same outcome with less
00:39:45
Speaker
consumption, less waste generation, why not choose that option? And it fits definitely more closely in with the
00:39:54
Speaker
the aims of the industry around your risk management for your sites looking at, as you said, is it going to, is remedying the site going to be a net gain or a net loss in terms of your sustainability and usage of different emissions and all that sort of environmental sustainability issues. And Daniel, have you got some technologies that you've had some firsthand experience with which are fairly new to the industry?
00:40:23
Speaker
Yeah, so actually fairly early on in my career, I was in a supporting role with a dear friend of mine's PhD, which was led through the University of Melbourne on permeable reactive barriers, particularly application of zero bale and iron for heavy metals. And that was, that was a really interesting project and a great sort of learning around for those sorts of more passive sustainable in situ technologies. But I think
00:40:45
Speaker
Globally, there's some really cool developments happening in the world of microbial kinetics at the moment. So yesterday I was reading an article in Applied Geochemistry, which explored the interface essentially between microbiology and geochemical kinetics, specifically in relation to how you assess and monitor microbial kinetics to better understand how chemistry, thermodynamics, temperature, nutrients, red option, organic matter, and all those wonderful sorts of things can either sort of impede or enhance remediation.
00:41:13
Speaker
And I'd love to see more of that research manifested in groundwater remediation projects. And I think as Lang alluded to, as the drive for sustainable remediation gets stronger, I think we'll likely see more of that kind of work coming through.
Groundwater Flow Dynamics
00:41:26
Speaker
Thank you. So I'm going to take a step back now to back to basics in hydrogeology. And I'd love for you to explain how to determine groundwater flow rate and direction. And in what situations this groundwater flow in different directions to what you might normally expect it to.
00:41:45
Speaker
So in the most basic terms, groundwater moves from areas of higher pressure to lower pressure. And that is often expressed in terms of a hydraulic head, which is basically the water level in an aquifer corrected to a datum.
00:42:06
Speaker
So the way we typically determine the direction of groundwater flow is that you install wells. Those wells are screened within the same aquifer, so you're looking at the same unit, and you
00:42:19
Speaker
measure the depth groundwater in those wells. You correct that groundwater to elevation from a datum and you compare those elevations between the wells and effectively you are moving water moves downhill in that regard. So you can create contours just like topographic contours on the ground surface.
00:42:42
Speaker
and contour the hydraulic head values, that will give you an idea of where groundwater is flowing. Obviously, the more wells you have, the spacing of the wells will give you a better resolution on that groundwater flow field. There's lots of examples of sites where broad assumptions were made on
00:43:02
Speaker
based off a small data set, small number of wells as the monitoring network grew, things changed quite a bit in terms of the understanding of which way groundwater was going. It can be complicated in the built environment because there are lots of things that influence groundwater, particularly a lot of contamination issues start at the ground surface. And so the
00:43:28
Speaker
first and typically most contaminated groundwater zone is the shallowest one.
00:43:35
Speaker
contamination moves to the subsurface to offer the water table. And that tends to be also the zone that has a lot of interaction with infrastructure. So it may be buildings that have free draining basements. It can be sewer mains that leak, and groundwater flows into the sewer main, or they leak outwards of it. That's what I'm saying.
00:44:01
Speaker
hydraulic high point. And some of those little complexities on a regional scale, you don't think much about, they're sort of a blip on radar, they're very localized issues. But when you're talking about a contamination source that's also on a localized scale,
00:44:19
Speaker
some of these sort of influences from, you know, whether it's construction dewatering on the side across the street, so it's old, you know, heritage, you know, high volume sewer main that draws groundwater in from
00:44:36
Speaker
you know, all around can have a real outsize impact. And those are the sorts of things that might result in groundwater flowing in a direction that you didn't think it might be flowing from the conceptual setting. You know, there's
00:44:52
Speaker
always you start with a bit of an idea from first principles that often groundwater recharges, areas of high topography, flows, essentially downhill discharges, low areas at the rivers, lakes at the coast. But these various factors can have a
00:45:14
Speaker
a really big influence at a local scale as to where groundwater actually flows, and therefore, where are the risks? Where's the contamination going? Is it actually going the direction you thought it was? And you've installed your wells in the area you thought the groundwater is flowing, and there was no contamination there, so there wasn't an issue. And then you would find that understanding and you figure out, oh, actually, it's all going the opposite direction. Yeah. And it actually is a problem. It is a risk of enabling property.
00:45:45
Speaker
Yeah, and I guess it's so important to remember in your design when you're dealing with small sites, because I guess in the contaminated land industry as a practice, don't often deal with landscape size, groundwater monitoring network. So yeah, definitely something to keep in mind. In regional New South Wales, especially in Tamworth where I live, the groundwater can be very deep.
Assessing Deep Groundwater Contamination Risks
00:46:09
Speaker
And I know this is an issue in a lot of regional New South Wales.
00:46:12
Speaker
Now, a rule of thumb historically has been that if groundwater is below 20 meters below ground surface, then it's unlikely that it will be contaminated from surface activities. Obviously, unless it's discussed earlier, Boor has provided some sort of a new migration pathway. Do you agree with this? Well, I think this was based on a lot of empirical data over the years of contaminated land and stream that if you
00:46:37
Speaker
have a release of a liquid chemical, for example, say dry hydrocarbons, that then has to migrate through 15 to 20 meters of unsaturated soil before it encounters the water table. You may see a lot of attenuation of that contaminant before it reaches the groundwater or it may never actually reach
00:47:00
Speaker
groundwater. The problem is that's just a broad generalization. There's a lot behind the likelihood of that contaminant propagating all the way through an unsaturated sound, the volume or the release.
00:47:17
Speaker
Are there geological features that actually performed as preferential pathways? You know, maybe, you know, groundwater at great depth, there may be, you know,
00:47:33
Speaker
fault zones or bedding planes or fractures in rock that promote rapid movement of contamination through the subsurface. So I'm never, like as an auditor, I'm never 100% comfortable when a consultant comes to me and says, well, the groundwater here is 15 meters, so we're not going to install any wells because we reckon it's not a problem. Typically, I will say, well,
00:48:00
Speaker
I'd like to see at least one well and you prove it to me. Yeah, definitely good.
Hydraulic Fracturing and Groundwater Systems
00:48:08
Speaker
What's the most interesting groundwater related project or remediation that you've both been involved with or individually?
00:48:16
Speaker
I'll give one example, and this was sort of related to the rise of the coal seam gas industry, maybe 10 or 15 years ago, particularly in Queensland. I was doing a lot of work around hydraulic fracturing risk assessments. Fracking a very emotive issue, a lot of this work was occurring in areas where there were
00:48:43
Speaker
high value groundwater systems supporting agricultural industries. Lots of concern about whether fracturing these deeper sort of coal measures was going to create hydraulic connections between the shallower
00:49:00
Speaker
high-value groundwater resources, where the chemicals used in the hydraulic fracturing fluids go to broadly contaminate these groundwater systems. And it brought together a really complex and diverse set of
00:49:17
Speaker
disciplines and expertise, I guess, to try to work through these issues. The ability to model fracture propagation from these hydraulic fracturing operations, the characterization on a very large scale of some of these groundwater systems. They were groundwater systems that were well understood, but we were previously talking about the small local scale issues. This is really the regional issues.
00:49:46
Speaker
the great artesian basin, groundwater systems being considered over hundreds of kilometers scale. And the understanding of the hydraulic interaction between those systems that had never really been characterized to that extent in the past because there wasn't necessarily a need to do it. So that walking into this project, you almost had to start from first principles in terms of getting the hydrogeology right.
00:50:14
Speaker
being able to make predictions about how hydraulic fracturing, you know, the extent to where you might make connections in the ground, and then the fluids, you know, lots of concern about what's hydraulic fracturing fluids.
00:50:30
Speaker
highly confidential. These are fluids that oil-filled operators have on the basis of billion-dollar industries. They don't want to share their secret sauce. That was probably the highest level of confidentiality agreement I ever operated under. They were forced to show the full
00:50:49
Speaker
recipe. In this process, on the back of all the hydrogeology then had all the toxicologists coming through all of these chemicals. Lots of them were weird and wonderful things. It's only there at fairly small concentrations. But yeah, that was quite an interesting undertaking from a groundwater perspective, both because of such an emotive issue and because it was quite a complicated one to try to
00:51:18
Speaker
assess from an impact perspective. Thank you. And Daniel, what's your most interesting project?
Challenges in Complex Geology and Renewable Energy Projects
00:51:26
Speaker
Some of the more interesting projects I've had the opportunity to be involved with involve that complex geology piece. So things like fraction bedrock where access and rebound is an issue, but also commingled flames where you have two different types of contamination, which are
00:51:42
Speaker
not necessarily complimentary from a remediation standpoint. So then you have to start considering things like the order by which you remediate and the impacts associated with that, which isn't always straightforward. So for example, if I treat contaminant A using whatever technology will I mobilize or exacerbate contaminant B, but then to Lang's earlier point, the risk needs to be factored into that decision. So what if contaminant A might be higher in concentration,
00:52:07
Speaker
but contaminant B could generate a vapor risk, then you may need to remediate contaminant B first to ensure that you are doing everything possible to minimise the risk of harm to receptors. And then there are those projects where you come across plumes that have like a 3D or diving element, and that can really throw the conceptual site model totally out of whack and change how we understand a plume to move or behave. So yeah, a few complicated ones, and they are always the more interesting and challenging ones from a practitioner standpoint.
00:52:37
Speaker
Mm, a puzzle. They do your head into the type of projects where you lay in bed at night thinking about them all the time. Exactly. So a very topical industry at the moment is renewable energy projects. So you've got your battery energy storage systems, wind farms, solar projects and the transmission line itself. And particularly in regional Australia, these are very hot topics with a lot of people. Now, I guess
00:53:07
Speaker
Looking at it from the surface level, you would think that groundwater and contamination may not really play too much of a part in these new projects. But I was really interested to find out from you both, are there any particular groundwater or groundwater chemistry issues that these projects will face either in construction or operation or even I guess in the decommissioning phase and potentially as legacy sites for us that we'll have to deal with in
00:53:36
Speaker
35 years' time. It's an interesting question. I had the opportunity to review the portfolio of energy assets for an energy company from a contamination perspective, and that included solar, wind farms, hydro. And essentially, what we found was that there was
00:53:59
Speaker
were relatively benign from a contamination perspective. A lot of the infrastructure is just at the surface. I mean, if you think about groundwater contamination, typically that comes from the use of some sort of substance that gets released. And so you have physical infrastructure at the ground surface that doesn't necessarily rely on
00:54:23
Speaker
hydrocarbons or other classical sources of contamination. The actual contamination footprint is relatively benign and limited to maintenance sheds that had chemical storage areas, that sort of thing. I suppose on the groundwater resource and
00:54:45
Speaker
impacts to people's access. Like any big construction project, if there's a large scale construction, the water that always has a risk of
00:54:56
Speaker
you know, lowering water tables, albeit usually temporarily. But in most developed groundwater sources, there's competition between various industries for the water. You know, the water is licensed. There's a finite amount that is available in the water market. Sometimes some of these big projects are granted water extraction volumes that surprise people, given that, you know,
00:55:25
Speaker
The rest of the users of that aquifer don't have access to those sort of volumes. Yeah, it's not an easy one to solve and it's usually quite a motive.
00:55:35
Speaker
And a lot of these projects are now being reclassified as critical state significant infrastructure, which I guess gives them a whole different realm to play with. And some of these projects are proposing to use mainly groundwater for construction purposes and in several cases exceeding the usage of local towns, water per annum.
00:55:56
Speaker
So, for instance, the Energy Co-Transmission Line EIS states that groundwater extraction will be 88 megalitres annually just for dust suppression. Any comments on, I guess, what this means in terms of the groundwater supplies and extraction out in western New South Wales?
00:56:14
Speaker
I suppose I would just hope that their environmental assessment of that activity is done with a high level of rigor. Typically, if you're looking at that planning approval process for an activity that involves groundwater extraction, there's an expectation on a minimum amount of characterizing of that groundwater resource, predictive modeling to see if I'm extracting these volumes in this particular amount of time.
00:56:42
Speaker
How much drawdown will there be in the aquifer? How long will that carry on? And how long will it take to rebound? And particularly in water sources that are heavily developed for agricultural purposes.
00:56:56
Speaker
These are groundwater resources that may already be under stress simply from the existing uses. The additive effect of having another large extractor superimposed on the stress from all the other uses can limit access to the water, the water quality. They end up drawing in older, deeper, more saline groundwater.
00:57:24
Speaker
Once you impact the groundwater quality in that way, it's much harder for that to recover. If you've drawn in really old groundwater that's been in contact with the subsurface for a long time, it has very high salt mode associated with it. Once the genie is out of the bottle, it's really hard to stuff it back in.
00:57:45
Speaker
And just off the cuff question, I know that radiation from naturally occurring uranium can be an issue as well in regional New South Wales. Is that something that we should be considering? Good question. That's one of the big gaps in my consulting career is radiation. So I don't know that I'm going to be very enlightening on that. In the US,
00:58:12
Speaker
naturally occurring radiation in the form of radons is quite a big issue and you know that really was the basis of a lot of the vapor intrusion mitigation work that's done today for volatile chemicals was based on research that was done to present radon intrusion into people's houses. I don't have a great sense of the magnitude of that issue in Australia but the fact that there isn't a
00:58:42
Speaker
a highly developed radiation mitigation industry in Australia is just to me that it's either something that people don't know about or that it's not quite the risk that it is in other places. I don't know, Danielle, have you had any experience in that regard?
00:59:00
Speaker
I have not. And I suppose the only thought that I would have is, obviously, this is where it's really important to sort of get the basics right, like your environmental setting and your understanding of the geology and the hydrology, because it is easy to miss things like this if you don't know what you're looking for and you don't pay attention to detail, but no direct experience, unfortunately. Well, fortunately.
00:59:29
Speaker
Well, thank you very much both for being a part of today's conversation. It has been really, really interesting to have these chats with you. It's an absolute pleasure to have you on the Contamination Station today. Thanks, Shana. Thanks so much. That wraps up this episode of Contamination Station podcast. Thanks for listening.
00:59:53
Speaker
You've been listening to Contamination Station, Safer Environment Together, an EPA funded podcast hosted by Chanel Gleason Wiley. We hope you've enjoyed our chat and been inspired to continue working towards a safer environment together. We would love for you to stick around for the next episode. So keep those headphones on, grab another cuppa and settle in for more insightful stories.