Thursday, November 2, 2023
12:00 – 1:00 PM MT
Learn more about chemicals that have been on the emerging contaminant treadmill for years, like 1,4-dioxane. Our speaker summarized the current and expected regulatory status, providing you with actionable knowledge to stay ahead of emerging contaminant challenges.
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This transcript was auto-generated by the webinar. Please forgive typos.
Hello. My name is Amy Blyth and I'd like to welcome you to today's webinar, Try Hydro's Beyond PFS: Understanding the Full Spectrum of Emerging Contaminants. Today our speakers will discuss the current and expected regulatory status of emerging can terminate and provide you some information on a fee. Few key emerging contaminants are excited to get started but I'd like to share a few housekeeping items with you.
First of all, all attendees are in listen only mode. At any point, if you have a question, please enter it into your questions form on the go to webinar panel. If we don't get to your questions in our one hour today together we will answer them directly via e-mail after the webinar. And also in your goto Webinar Attendee panel, we've included.
After the webinar is done, there is a survey, so we hope that once you close out, you'll take a few minutes to fill in that survey so you can give us some feedback on today's webinar, as well as future webinar topics that you might be interested in. This webinar is being recorded and will be available to all participants after the webinar is offered.
OK, so here's here's a look at our agenda for today. We're going to cover what are emerging contaminants go over to the regulatory process, transport in treatment and emerging contaminants, light, and final thought. Alright. Let's go ahead and introduce our speakers, Mitch. Olsen, who is our tri hydro's Emerging Contaminants Director, he has a professional engineering license with 23 years of experience in academia. And Consulting. Mitch has a chemical engineering from the University of Minnesota Duluth and an MS and PHD. From Colorado State University and Environmental Engineering.
Mitch routinely participate in webinars panel, discussions, and technical presentation addressing environmental challenges involving chlorinated, solvents, hydrocarbons, and emerging contaminants. Next up we have Tile macdonald. He is an environmental science.
Scientists, excuse me, with over a decade of experience successfully executing a diverse range of fire and mental projects nationwide.
He is a group manager for Tri Hydro's Energy Resources, Energy Services Team and has expertise in a variety of conventional and emerging in the fire mental cadence. And last but not least, we have ...
He is based in Tri Hydro's Lakewood Colorado Office and has 20 years of experience in environmental remediation. French's Try Hydro a subject matter expert on 1 to 4 Dioxane is a trainer on the IT RC 1 4 dioxane T. He has project experience was several of non P fast emerging contaminants that we will discuss today. And with that, I'll turn the presentation over to you ....
Amy, Confirmed by you sharing your screen.
Oh, my apologies.
There we go. Can you see it now?
Yep, got it. Thank you. All right, Sorry about that.
All right, very good. Starting off with what are emerging contaminants? So thank you for that introduction, Amy. Next slide, please.
So I'll start off with a comment on the term emerging contaminant versus contaminants of emerging concern. Officially, contaminants of emerging concern is is preferable. And that is because of the emerging contaminants implies that these are new chemicals, but most of these substances have, in fact been used are produced for decades before emerging as a contaminant. So the term contaminants of emerging concern highlights the fact that it's the concern effectively that's emerging, not the chemical itself, for the purposes of our webinar. I may use these, use these terms somewhat interchangeably today.
In fact, I'll probably lean towards the term emerging contaminant, mostly because it's easier to say. So please don't judge me for that. So that being said, emerging contaminants can take many forms they may be released as is or they may be a product of a breakdown of another substance.
They may comprise physical particles such as micro plastics or nanomaterials. Then maybe chemicals, biological substances, such as viruses, or bacteria, or toxins that are related to these, or radiological substances. A common theme for these substances is, that they are newly identified or a re-emergence. In terms of new data that becomes available or understanding of existing data, This data may relate to occurrence in the environment or otherwise understanding of effects on human health, aquatic life, or the environment.
Being emerging contaminants, data are typically limited. The data needed to assess emerging contaminants can be related to occurrence data, the first two on this list, Concentration and pervasiveness would address this or may be more related to effects of these compounds such as toxicity or ecological impacts. Finally, emerging contaminants are anticipated to have widespread occurrence at significant concentrations. This may be due to diffuse or, or point sources, But typically excludes events were risk or harm is associated with a single, catastrophic release of toxic chemicals. Usually. This is when we're talking about emerging contaminants were referring to something with a more widespread occurrence and potential risks.
Next slide, please.
There's not a formal process by which emerging contaminants emerge, but there are typically a chain of events that that that may be followed. So as noted, the, the release of contaminants of Emerging Concern or Emergency contaminant it.
That this is often the case, that they may have been released over years, or decades before, being discovered The release mechanism might be direct directly into the environment, such as through air discharge, atmospheric discharge, or through the water. Or in a lot of cases, as we'll talk about, a lot of chemicals are used in household or chemical use that might be discharged to a wastewater treatment plant. And these treatment plants may not be designed to treat a lot of these chemicals, especially if they hadn't known that they were present. But, somehow, a discovery or awareness triggers why more widespread awareness of these chemicals need to look into them them further. So, some sort of a concern, it might be an events that leads to a front page news, but a lot of different forms that this discovery might might take, depending on the type of chemical. But the next phase then, typically involves data collection. Evaluate the occurrence and multiple media types to get a broader understanding of where these chemicals may concern, and how broad the the potential impacts might be.
Then evaluation of the data, in terms of currents, getting a broader understanding of these chemicals in terms of transport potential, different properties that would govern how they might move in the environment.
And then the subsequent data in terms of potential for exposure and toxicity.
So then following these, these stages, data collection and evaluation of the data create some broader level of understanding.
Then the, um, the emerging contaminants might be prioritized. In a kind of a broad brush, strokes, sense looking at how they met the pirates are as low priority contaminants. They may have had some initial discovery and concern but after further data evaluation, it's decided that no further action is needed at that time.
Some mid-level contaminants might kind of go back to this process again. There might be enough to raise some additional concerns and go back to the data collection evaluation process, high priority emerging contaminants that may then proceed into the the rulemaking process.
There's an IPRC: Confinements of Emerging Concern Team that is in the process of producing a document, so good information there in terms of the process and guidance in terms of how how these steps might be followed for a new contaminant founding a new area.
Alright, so now we'll talk more about transport and treatment and some general context for emerging contaminants. Next slide.
So emerging contaminants may be released directly into the environment via atmospheric discharge or water or some other mechanism. And as mentioned, the common release mechanism for emerging contaminants may be involve emerging contaminants being present and domestic or commercial water, and then discharged to a wastewater treatment plant. Ultimately, the transport of emerging contaminants is a factor of many chemical properties, such as volatility, solubility POC potential for great ability. There are many emerging contaminants and many processes, really too many to try to cover everything here. For our purposes the webinar today, we'll talk briefly about the drinking water process and the wastewater treatment process since these are two primary mechanisms through which emerging contaminants may be present and maybe a primary concern and need to be addressed.
So starting off with looking at a public water, supply system, p.w.s., drinking water, supply system, and how, how these might have to manage emerging contaminants as they may be discovered. So stepping through the water treatment process if, if an emerging contaminant is discovered in the water source it off and might be the case that if, if an alternative source can be identified, that might remove the need to have to treat the emerging contaminants through the water treatment process. But in the absence of that if if if an emerging contaminants present in the water used for drinking water system can't be replaced looking at the drinking water treatment process generally limited in terms of ability to treat a lot of what we consider to be emerging. Contaminants, The typical process involves coagulation ... sedimentation. This is the process through which the coagulation positively charged particles added added to to adhere to dirt or particles at 10 to the negative charge. And then, through the ...
sedimentation process these particles which would be removed, some contaminants might become bound up in the solids. But most of what we're looking at in terms of emerging contaminants would tend to make it through that part of the process.
And then through filtration, which may not be designed to speak to treat specific emerging contaminants, that filtration might involve sand filters, Carbon filters that I that can effectively remove a lot of organic chemicals, organic, and in particular, it's other things that might be organic chemicals, but may not be designed to remove our L a lot of the emerging contaminants. And so, an additional filtration step could potentially be needed here and we'll talk a little bit more about what other types of removal processes might be useful at that stage. And then comes the disinfection process where chlorine or UV is used to remove any remaining bacteria. Microbes that might be present before distribution.
Next slide please.
Now, looking at the wastewater treatment process, wastewater treatment plants may become discharge points for emerging contaminants through no fault of their own, but because so many emerging contaminants originate or through their use they become discharged in household sewage or industrial discharge that's ultimately fed through a wastewater treatment plant. And waste typical wastewater treatment plant processes aren't designed to remove emerging contaminants, Although a lot of a lot of organic chemicals may be removed through the typical conventional wastewater treatment process. But, just going through the process briefly and considering what the fate of a lot of the emerging contaminants that we might be looking at would be initially come solid removal through.
Buyers screen and grit removal. So, some solid particles, some micro plastics at more core size might be removed through that step.
That's followed up with the sedimentation tank or or or primary clarifier. Additional solids might be removed the step some finer solids.
But, typically soluble chemicals are going to continue to remove, too, to proceed through the process through this step. Then following that is the aeration, activated sludge step, and that's kind of a loop or closed loop process. Or open the processor with a secondary clarifier and that's a chemically active process.
Constituents that are susceptible to aerobic degradation may very well be degraded in this, this very biologically active step.
Also, a lot of organic chemicals may partition into the sludge during this process and then ultimately be pulled out with the with the sludge which can suddenly be digested and treated and used as biosolids.
But a lot of the soluble constituents, if it's not easily degradable, under the aerobic conditions, may then proceed through the secondary clarifier and, and be discharged. The discharge limits for wastewater treatment plants would be governed by NPCS discharge permits. And so whether or not a particular emerging contaminants are are covered by NPS discharge permits is, it would be a big factor as to whether subsequent treatment would be needed before discharge for water.
And then also regarding constituents that, my partition into the sludge a lot of biosolids are re-used or land applied maybe for agricultural purposes purposes. That is another pathway through which emerging contaminants could potentially enter the environment as if they survive the iteration process partition into sludge and become part of biosolids.
Um, so now, considering treatment processes, this could apply to drinking water, or wastewater treatment plants, where additional treatment is needed also, where environmental sites where groundwater or soil remediation is being conducted and in generating streams that need to be treated for certain compounds. So there are several off, the shelf widely available technologies used for water treatment that can be effective for a lot of emerging contaminants. And so of course, none of these is a one size fits all for the particular contaminant need to look into the different options here to see what the best fit is. Granular activated carbons typically the goto treatment approach. Effective, removing most non polar, or organics, can be very effective for reasonably efficient for high volume flow type type systems, such as might be encountered into drinking water treatment plant. But also available. And much smaller scale point of view, state type systems as well.
So option or i-ops on exchange resins can also be widely used. ... may be effective for organic compounds, just 1 4 dioxane, which we'll hear a little bit more about a little bit later, which which aren't very effectively removed through kind of activated carbon.
And also ion exchange resins, which is affected by the use for polar compounds, also can be used for treatment of wide range of flow rates.
High pressure membranes are also common approaches that can be used for a wide range of of emerging contaminants.
one key advantage of, say, reverse osmosis is through a very fine membrane and high pressure to drive water through. It can effectively remove just about anything from from water, even down to individual atoms. The, perhaps the downside of that is high pressure drop, and potentially a relatively large volume of ... is is generated that would need to be disposed of.
So a lot of the volume may may not, ultimately, be treated and require some sort of subsequent treatment or disposal, But reverse osmosis overall is versatile and removing a lot of CCS.
Advanced oxidation processes are also can be widely used, can be very effective at removing wide variety of organics of organic chemicals, and particularly, may be useful for low bio degradable, bio degradable, chemicals, or highly stable compounds.
An advantage of advanced oxidation versus the others is that gack and ion exchange these membranes just remove the compounds. These advanced oxidation processes actually it would degrade and can effectively mineralize most organic compounds.
So we can think about where these might be plugged in in the, in the water treatment process. So, next slide, please.
All right, now, we'll talk a little bit briefly about the regulatory process for emerging contaminants. Next slide.
Alright, if if the regulatory process for emerging contaminants seems convoluted, there's, there's a reason for that. The mere existence of a chemical, doesn't warrant regulation. All these steps of the process really need to be evaluated. And ultimately, the idea of regulation is to protect the population, getting that last step of this chain here, to minimize population harm. But all these data, he needs to be generated and evaluated through all these steps in the process, from release and exposure, through effects on an individual, consumer, or a person who's exposed to these chemicals. And whether that creates larger scale changes within a biological system, that ultimately leading to disease. And then, whether it's widespread enough to actually create a broader population harm, so that the data that needs to be generated needs to consider this from the beginning to the end.
And ultimately consider whether cost savings of the population on what is the value of that of reduction in population. Harm at the end is worth the cost in the upfront steps of this process, and that's kind of a balancing act of these these regulations.
There are several different regulatory pathways that might be followed at the federal level. These are administered by the EPA, but briefly going through some of the more commonly, applied processes. The Safe Drinking Water Act program is, is the program through which maximum contaminant levels or are empty cells are developed?
That Tasker, Toxic Substances Control Act is used to identify and collect data and provide potentially some restrictions on new chemicals coming into the market and collect data in terms of the occurrence and production on a new and existing chemicals. The Circular Zoopla Superfund Program is a program through which enforcement actions may be conducted and site investigation and cleanup.
Maybe may be conducted Clean Water Act, Clean Air acts.
Both of these involve permitting discharges to the two surface water and air, respectively, and may involve programs for involving sampling and characterizing what maximum concentrations might be allowable in their respective media.
As far as state level evaluation processes, a lot of the early steps of contaminants, emerging talent regulation, occurs on a state basis. In part, because states can be a bit more flexible in terms of their approach, and we think of states as being the micro laboratories for the, that the federal government.
There's really too many approaches to try to cover on how things are approach at a state level basis, but we do see as new contaminants emerge how widespread how variable the processes and results can be across different states.
OK, next time.
The Safe Drinking Water Act has a mandated regulatory process and we'll talk briefly about that here. This has got a process through which emerging contaminants are evaluated and then ultimately may become the subject of maximum contaminant levels are empty cells. This is a process that EPA undergoes A mandate to go through every five years, and starting with this candidate contaminant lists, which is basically the identification of potential emerging contaminants. That that and evaluation as to whether additional scrutiny of these compounds is required. And then that's followed up with the unmake Unregulated contaminant Monitoring Rule, ..., which is the data collection approach. The CMS requires drinking water sampling across the country. So, the CCL is the identification phase You Samira as a data collection phase. And based on the results through all this irregular Tory Determination may be made that's basically a yes or no step, in terms of whether regulation would be needed for a new compound.
And then finally, that the National Primary Drinking Water Rule, or MP, DWT, are that's that's the MCL development process. A lot of opportunities for public review. Those are highlighted in here. So we can see there's multiple steps in between each of these multiple steps in the regulatory process. EPA can also establish health advisory levels, which are not enforceable levels if they want to provide some sort of a benchmark for comparison as they are proceeding through this process with a new set of compounds.
So just a quick overview of what the CCL list has looked like. There's been five iterations, going back to the late nineties, quite a large number of chemicals evaluated each time through. Next slide.
And looking at the substance use EMRs, also five iterations of that, but kind of quick overview here: of what the different chemicals, up to 30 chemicals, through each iteration of ... program. And you see my program, again, five iterations of, that each of those involves a sampling of drinking water systems across the country. So there's very widespread data that's generated through the ... process, and that's what's ultimately used to to, to determine whether to proceed with regulations. Next, slide.
And following that up, here's a quick snapshot of a few of the chemicals that were we'll be looking at a little bit more detail in the subsequent slides here, and how they've appeared in different steps of this process, the CCL, and use EMR program. And I think interesting and worth pointing out, that a lot of these have had multiple iterations on the CCL, and may or may not have been picked up in the ... program for the data collection.
And one final note I wanted to make on the regulatory side, the EPA has a useful tool for evaluating a lot of these emerging contaminants that do not have regulatory values for comparison yet. The regional screening levels, These tables are available through the circular websites. These are based on what EPA's latest assessment of the most recently updated toxicity values.
R and then calculations based on different exposure scenarios, and, and so these are tabulated for a lot of compounds to which the entire regulatory process has, has not been completed.
But through which there is some toxicity data, and and so some basis for comparison can be drawn from these RSL tables.
And I will shine the spotlight on a few select emerging contaminants, and Kyle and Fritzl will take over for that section. So I'll pass this onto Kyle here now.
Yeah, thanks for that. Next slide, Amy.
So this slide is just showing you some select, emerging contaminants, contaminants of emerging concern.
I really the purpose here is just to show that there are CDC's out there other than the P fast and look for dioxin and the like will spotlight a couple of a couple of them, a couple of these that are listed here.
These are probably some of the more, uh, notable are well known CDC's. We also have listed here some of the past emerging contaminants.
And these are chemicals that may have gone through that process that that Mitch had just discussed of being identified as emerging contaminants and now are not really thought that thought to be emerging contaminants anymore. So that sort of made their way through that whole process.
Next slide, please, Amy.
So, we'll start off our spotlights with micro plastics.
And this is an emerging class of emerging contaminants that really has garnered increasing attention over the last two decades or so and these are plastic particles and plastic fibers generally ranging in size from about one nanometer to five mm.
There is a subcategory of this of nano plastics and these are the plastic particles less than one nanometer in size, and sometimes they are included in the definition of micro plastics, sometimes they are not that definition really does differ among various organizations.
There are two primary sources, two primary categories of sources for micro plastic pollution.
So, there are manufactured micro plastics. These are referred to as primary micro plastics.
Those that are intentionally manufactured or produce for specific applications or for score for specific products. So this includes things like abrasive beads that are used in personal care products, like toothpaste or face cleaners. There's also several types of coatings that are used on on seeds and fertilizers and pesticides and other agricultural products.
The other category of sources is micro plastics that are formed through the degradation and weathering of macro plastic materials. So these are referred to as secondary micro plastics.
So natural degradation, processes, such as, is photo degraders, photo degradation, and weathering, or anthropogenic processes like washing of clothes, or wearing of tires, can contribute to micro plastic pollution.
Regardless of their origin, micro plastics are considered to be ubiquitous in the environment.
They're typically more abundant near urbanized areas, but they've been found all over the world from ice sheets in Antarctica, to sea salt, they've been found in surface water, groundwater, wastewater, soils, and sediment, and biota, really worldwide.
Um, most of the studies focus on the marine environment in terms of distribution.
It's important to note that land based micro plastic pollution is maybe even greater, and some estimates range up to 23 times greater, micro plastic pollution on land relative to that that's directly released into the oceans.
Exposure pathways to humans include ingestion of contaminated food and water, or inhalation of micro plastic particles.
The potential dermal contact exposures as well if soil or personal care products that contain micro plastics.
Bio accumulation and trophic transfer are areas of concern for micro plastics in their areas of active research but mycoplasma have been detected in, in human blood.
Deep lung tissues, placental, tissues, human excrement, the health effects attributed to ingestion of micro plastics includes inflammation, immunosuppression, oxidative suppressed, oxidative stress, potential reproductive effects.
But beyond the impacts of the plastic particles themselves. one of the primary concerns regarding micro plastics is, health and environmental impacts that are associated with ... chemicals.
So, since micro plastics have are very small particles, they have a very high surface area to volume ratio.
And they can have surface charges and can soar chemicals, as they migrate through the environment, or can have chemicals stored from their manufacturing processes, such as solvents are catalysts are plasticizers.
The fate and transport of micro plastics really does vary widely.
Mainly due to the extreme diversity of this contaminant class, the, their transport to the environment can, can be influenced by a number of variables, including their physical properties, like size, density, shape, or chemical properties, like the polymer type, any additives or ... slash substances.
So the state of the Science on micro plastics is really rapidly evolving, and this is likely to lead to the development of regulations.
As the associated risks become more understood, there is an IT or C micro plastics team and they have a guidance document as well. It's a really great resource if you're looking for more information.
In terms of regulatory status, at the state level, the ICRC did a survey in 20 21.
Uh, and of all the states and the respondents of the respondents, they found that there's really limited state level sampling for micro plastics. I think only four States had responded that they had sampled for micro plastics. And, and there are only a few states that responded that they are considering criteria or standards in the future.
At the federal level, regulations are still nascent.
There are some some regulations that do apply includes the micro be free waters Act of 2015. This prohibits cosmetics containing micro beads from being manufactured the Save Our Seas Act 2 0 of 2020.
This provides grant funding for microfiber Pollution Prevention Strategies, and the 2022 Infrastructure Investment and Jobs Act, which also allocated funding specifically for micro plastics and identified micro plastics as an emerging contaminants.
There are other state and federal regulations that address macro plastics and pre-production, plastic pollution.
Those might ultimately have an effect on the generation of micro plastics as well.
Next slide, please, Amy.
So techniques and best practices for for sampling micro plastics and analysis are still evolving.
And so a comparison of data that's been collected from, from various studies to date is is challenging because of the differences in sampling techniques and analysis methodologies that have been employed.
There's only been a few methods that have been really widely adopted, the ASTM in 20 20 released a standard for water sample collection and a standard for water sample preparation.
Um, but, really, the, the extreme diversity in micro plastic, particle size, shape type, you know, coupled with that lack of a universal definition, and lack of standards for sampling.
It really highlights the importance of defining your data quality objectives before sampling.
Uh, yeah, there's, there's currently no standardized method, even for just reporting your analytical results.
So depending on your sampling goals, your micro plastic analysis might be quantified in terms of mass or in terms of total mycoplasma count.
Typically, for sampling, procedures include your field filtration or receiving step.
This is also often done in liners or slipstream and for water samples can require a very large volumes of water. Recommendations or up to one thousand liters of water in order to maximize representativeness of your sample.
Next slide, please.
In terms of treatment, source reduction is really the first and best step to prevent micro plastics from entering the environment.
Conventional drinking water, and wastewater treatment processes have shown fairly high removal rates from water.
So drinking water treatment plants they can achieve 70 to 83% removal using those steps that micha discussed coagulation flagellation, sedimentation, filtration, and combined treatment processes here would typically be more effective.
Remember, infiltrations also have very effective removal rates, the data shows, but may have some limitations for large-scale applications, as, as mentioned, discussed.
In terms of conventional wastewater treatment processes, they also report fairly high removal rates, but some of the micro plastics may still remain in that treated effluent just simply due to the higher influent quantities that are coming into wastewater treatments.
Further, the data show that 50 to 85% of micro plastics could be retained in the sewage or biosolids, which then, again, are commonly applied to farmlands and could contribute to soil pollutions.
An important note here is that the existing research here primarily focuses on micro plastics and there's been limited attention given to nano plastics in terms of these removal efficiencies for four conventional treatments.
There are a number of emerging treatment technologies that are designed for micro plastics specifically are there in the early stages of development generally, but there's some promising and interesting approaches that are out there include use of acoustic waves, photo degradation, photo catalysis, electro coagulation, and magnetic extraction.
Next slide, please.
All right, so our next CEC, spotlight is six PPD Quinones.
This is a contaminant that is.
Gain notoriety. It really did in 20 20 when researchers in Washington State identified 60 PDQ as being solely responsible for large-scale salmon die offs, or that have been observed in the Pacific north-west for four decades.
six P PDQ is a transformation product of six TPD six PPD another PBDE chemicals are added to tires during manufacturing.
It concentrations up to percent level composition, to help protect the tires from degradation.
To achieve specified safety standards in the tires.
six PPD is the primary anti tire degrading chemical used in tires since the 19 sixties, and it's designed to react with the oxygen and ozone to protect the tire from cracking and from degradation.
So when six TPD reacts with ozone, it forms this related chemicals six PDQ and that's the culprit behind the salmon die offs.
Um, research behind six ... is ongoing and new in terms of transport toxicology.
Remediation, as as with many of these emerging contaminants we'll discuss.
But studies have shown acute toxicity to aquatic life, particularly coho salmon, or some other related species, brook trout, steelhead, and rainbow trout.
Coho salmon are, in particular, highly sensitive.
They have a median LC 50 concentration of just zero point zero eight micrograms per liter that reads leads to rapid mortality.
Sub lethal effects include impacts on growth reproduction, susceptibility to other stressors like temperature or pathogens.
Notably, many other fish show lower or no toxic effects.
2 six P PDQ, including other salmon Ids, like Chinook or Atlantic salmon.
Beyond, impact to aquatic species, human health effects of six PPB and six PDQ are areas of active research.
The parent compound, six P P D, is well documented as askin Sensitizer and it's listed by the European Chemicals Agency as a Category one reproductive toxic hint.
600 PDQ is predicted to cause oxidative stress and liver lipid accumulation.
The primary transport model, shown on this cartoon that's on your screen now involves the tire wear particles. The ... being transported by storm water or air into surface waters or sediments.
There's potential routes of exposure that also include inhalation, particularly near high traffic areas.
Exposure via drinking water and bio accumulation effects are still areas of active research.
In terms of distribution, it's been found in various environmental media. Stormwater surface waters, sediments, soils, rubber products, and even human urine.
Elevated concentrations in surface waters are highest, typically, during or immediately following rain or snow melt events.
six P PDQ is expected to soar to sediments and particles and that could prolong the duration of elevated concentrations in surface waters.
EPA Screening Levels do not exist for six PPD or six P PDQ.
But the EPA is in the process of developing draft screening values for these two compounds to protect sensitive Salmons species and other aquatic life.
California and Washington State are really leading the charge in terms of regulatory actions.
They're developing action plans, Allocating funding research.
They're regulating the use of six PPD.
The motor vehicles, State of Maine and Minnesota have identified six PPD's chemicals of concern.
There's simultaneous Federal Action plans that are addressing concerns of six PBDEs, 60 PDQ, as well as other chemicals.
In terms of exposure pathway through, tire Crumb rubber that's used in synthetic fields, next slide, please.
Environmental sampling for six PPD and six P PDQ can be challenging primarily due to the low and intermediate concentrations of these chemicals. So passive sampling technologies are being developed to address that issue.
There are commercial and research laboratories that contest, for six P PDQ and Water, and the US.
EPA is developing a Clean Water Act, 600 series test method for detection in surface and stormwater.
There's limited studies that are the effectiveness of conventional wastewater treatment plants for removing ... PDQ, but the fact that these chemicals tend to ... organics, really raises questions about their accumulation and sledges biosolids.
one of the primary areas of research in terms of mitigation is, best management practices.
For modifying storm water systems are adding BMP retrofits to urban roadways to enhance filtration.
There are also efforts being made to deploy and identify alternatives to six PPD tires in order to reduce or eliminate six PPD, Q in the environment.
So, states like California and in Washington State are pursuing policies.
To promote alternative tire compounds in the State of California as just as of last month, begun regulating six P P D and motor vehicles, the or they are safer Consumer Products Program.
Next slide, please.
So, the next CEC spotlight is ethylene oxide, itto.
This is a flammable colorless gas. It's used in the manufacture of many other chemicals for a range of products, including anti freeze Techstyles, plastics detergents adhesives.
Additionally, itto is used to sterilize medical equipment in certain food products, such as spices and dried herbs, and other things that can't be sterilized by the use of steam.
When itto's is produced or used some of it may be released into the air. This is really the primary focus exposure pathway.
Liz via air emissions exposures the a water source into soils and sediments is not really unexpected pathway for itto.
Um, it's known to be a carcinogen, particularly to two people who are regularly exposed over extended periods.
So, long term exposures to each various cancers, including blood cancers and breast cancer, in women, acute exposures can lead to respiratory irritation, lung injury, headache, nausea, et cetera.
Exposures to ceramic communities resulting from ito emissions are a concern, particularly from large chemical facilities or commercial sterilizers, but little data exists to show that acute health effects are resulting from this pathway.
So, as such, regulatory efforts have really primarily been focused on reducing long term exposures to workers and identifying safe alternatives to itto and it's used for sterilization.
US EPA ourselves do exist for Ito and air soil and water they're listed here on the slide.
Um, in April 20 23, EPA issued three proposals to reduce risks WTO exposure to workers, and to surrounding communities.
Including proposal's regulated under the Clean Air Act, the Toxic Release Inventory, the Federal Insecticide, Fungicide, and Rodenticide Act Pfeffer.
They will all apply to emissions from chemical plants and commercial Sterilizers.
Additionally, EPA recently published a risk assessment that discusses lifetime risks for itto exposure in occupational settings into communities near commercial sterilizers.
None of those studies found an indication of acute or short, short-term health risks associated with routine use of ito at sterilization facilities.
But they did find the highest cancer risks are for workers who directly handle itoh over the course of their entire career.
With that, I think we'll hand over to Fritz to take it from here.
OK, thank you, thank you so much, Kyle. If you go to the first 1 to 4 Dioxane slide, thank you, Amy. So yes, going to speak to a few more emerging contaminants quickly at the end of our talk, before I hand it back to Mitch, to close it off. If one is interested in more than two minutes, if you want it to our presentation on 1 4 dioxane, the ICRC team has one coming up next Thursday, November ninth. So if you want much, much more detail on this emerging contaminant, please sign up for that. But here's the Cliff Notes version. This compound was used as a stabilizer for 111 TCGA as well as in a lot of different consumer products.
But uses a stabilizer is where we find it most commonly in the environment and based on the increase in popularity of 111 tika. And then facing that out due to its ozone depleting properties. Production peaked in the 19 eighties. But because of that historical use, this compound is commonly associated with with chlorinated solvents sites.
EPA considers it to be likely carcinogenic. Can also cause kidney and liver issues.
There is not currently a Federal MCL. For context, EPA has an RSL regional screening level of zero point forty six parts per billion. So a little bit less than a part per billion about an order of magnitude lower, concentration of reference, then things that we more commonly hear about benzene, trichloroethylene, etcetera.
And we'll talk about state issues on the very next slide. So, stay tuned for that. That graphic on the right hand side gives a snapshot of occurrence, this is based on data from UC MR three. About 10, 10 years old by now. Detected in 21% of US water supplies, quite prevalent out there, the those different dots represent the, the magnitude of the concentrations and all but the very smallest size on that map indicate essentially exceedance of the of the RSL in public drinking water. This is based on sources in groundwater surface. Water shows, very similar concentrations are very similar trends. I should say as well. Widespread detection and many exceedance is of that of that reference level. Very. Interestingly, ... were also in ... July 23, 1 4: The accident was more prevalent in that study yet.
Since that time, we all know what has has dominated the news, but we won't talk about PFS anymore in this in this talk. Next slide.
So this is the state map showing different regulatory standards for for 1 4 dioxane. A few states have promulgated MCL ELLs and many of the other states shown on this map have other regulatory standards on many of which are enforceable is as well. So even though there's not yet been action on a, on, a federal level taking, Colorado, where I live is an example. The state has a groundwater standard of zero point three five parts per billion, so in many ways, in many states, this, this contaminant has has emerged on the on the state level.
If you want more info on this, you can again see the ICRC one for X in tech reg document online. Next slide, please.
So, what are some of the physical properties of 1 4 dioxane has that cyclical ring structure that you, that you see on the top there. It is highly soluble in water, and it's also sparingly volatile. So, it also does not, does not absorbed very much to soil at all. So, if one were to continue consider partitioning properties, you know you have various constants that compare air to water to solid phase concentrations. For this particular compound, the vast majority will end up in the in the aqueous phase. This has a consequence of leading to a relatively great propensity for this compound to get leached into groundwater from near surface releases and then to form groundwater plumes once it once it reaches the water table.
1 four dioxane is is treatable, though the the list of technologies that can treat it is somewhat less than than other compounds. Advanced oxidation processes, highly sophisticated ex situ processes. Those can break apart that ring and degrade 1, 4 dioxane as they can with with many organics.
Additionally, there's been a whole lot of focus lately on biological treatment processes for one for taxiing bacteria have recently been isolated that can degrade 1, 4 dioxane as a primary substrate, IE they gain energy from that that reaction.
Additionally, there's co metabolic bacteria that can also act on on 1 4 dioxane because one for the vaccine is so soluble and so sparingly, exhorted It does have a lot of potential for phytoremediation treatment. Last bullet there, Many common elements of pump and treat systems, for example, air strippers, also activated carbon. 1 4 dioxane is not particularly effective for, I'm sorry. Those methods are not effective for treatment of, one for X in. The relevance here is that there have been a great many sites where pump and treat has been used to treat chlorinated solvents plumes with people not fully aware that. That 1 4 Dioxane was also present in the mix, the 1 4 dioxane passed right through the treatment mechanisms, so that is something to keep an eye on for, for this particular compound.
Next slide, please.
Changing gears going to talk about another another cyclical compound.
This is Sulfa land, a bit lesser known, and then some of these others. This has been widely used in petroleum distillation refining. Other chemical processes can pull aromatics. Out of other hydrocarbons, purify natural, natural gasses. So very industrial usage for this, this chemical, in, in high concentrations, it does have effects on the central nervous system, including some, some symptoms listed there.
From the regulatory perspective, this one actually dropped out at the contaminant candidate list Back, say, 10 and 10 years ago, these other things went on and made their way through the process. This one, this one, didn't make the cut for whatever reason, EPA has still set an regional screening level for this. That's 20 parts per billion.
So, not not as low as standard, as some of these other things that we'll be talking about. State of Texas has a their equivalent of an MCL. And the industrial one is shown there the residential is lower, so is regulated in the in the state of Texas, not to such low concentrations and given this compounds uses in industrial chemical and refining processes, it's it's commonly associated with with those types of sites.
Next slide please.
Similar to 1 4 dioxane sulfur Wayne is soluble in water not terribly ... did not particularly volatile.
So, once again this does have a propensity to get into the aqueous phase, stay in the aqueous phase and can form groundwater plumes as a as a consequence with respect to treatment. We we've looked at this compound, actually, at a few of our own sites and based on our experience, the literature, as well. Aerobic bio degradation methods are seem to seem to work, OK. Anaerobic processes not not so much. So in in anaerobic subsurface environments, if there's other petroleum hydrocarbons, there, we would need to look at it processes to make make more rubik conditions ex, Situ bioreactors, for example, moving, bed bioreactors, such as that shown on the right. Those, can be a good option advanced, Oxidation is as well and based on the ability to oxidize this, this compound some in situ chemical, oxidation, or ESCO chemistries those to treat this this compound in in situ.
Last emergent contaminant that we will talk about today is 1 2 3 tri chloride propane or TCP. This was an impurity in. soil fume. Again, it was used very heavily in agriculture, particularly in, say, the Central Valley of California wasn't the active ingredient, but was there at present level concentrations, and due to widespread application of these fume against has ended up in groundwater? It is believed to be a carcinogen, and while it does not have a Federal MCL, It was detected somewhat frequently, and you see M R three. The regional screening level is zero point zero zero zero seven five parts per billion dollars. So we're down in the single digit parts per trillion range for this particular compound. The State of California has an MCL in that same range as well, five parts per trillion, or zero point zero zero five parts per billion.
Some other States have have regulative this also.
And this is a relatively widespread in areas where it was used for for agriculture. The USGS has done some surveys and detected in 3.5% of domestic supply wells in agricultural areas. And with a, such a low reference concentration, a detection may very well be be an exceedance. This, this generic graphic on the right is a, is a mock up of something. We've looked at it in a different area. Looked at at pesticide application regulations that are on file with with government agencies and have seen hundreds to, you know, multiple hundreds of pounds of 1 2, 3 TCP apply per section of land. Compare that against a part per trillion MCL. And you can see how there might be potential for issues with respect to physical properties.
Not too much is known about the degradation of this compound, though it does seem to be fairly recalcitrant. Not terribly ... as a consequence of those things can be mobile and groundwater.
We have, at some of our sites where we worked with this, found that activated carbon is it can successfully pull it out of out of solution. There are studies indicating that reductive ... nation similar to what what what one would use for TCE and the like. That can be effective but achieving parts per trillion endpoints that's really the challenge there. Similar type of issue with monitor natural attenuation or MMA, there are degradation and attenuation mechanisms. The The rub is in the endpoint there. So, with that, I will move on to the next slide. And I think we're going back to Mitch to, to close us out.
I think there we go. Read, unmute. Thanks, Amy. So wrapping things up here. A couple of concluding thoughts here on the Emerging Contaminants front. So we've, as Kyle alluded to, kicking off the spotlight section, we have a few sort of cherry picked emerging contaminants that we had focused on here. There's many, many compounds out there that are on some emerging contaminant list or or other.
There's, there's different lists depending on types of sites and we're looking at this is one Emerging Contaminants overview summary from this article cited here on the bottom right corner of the screen. But I just want to give an overview of what else is out there in terms of what what's on the emerging contaminant front. Some of these I knew most of these are old and have been produced for a long time, but a lot of industrial chemicals. Even some illegal drugs make this list.
And pharmaceuticals and personal care products are pretty broad category that have gotten quite a bit of attention on the immersion contaminant front over the past 20 or 25 years. And they're still there. They haven't gone away. But they're also among the chemicals on this list. So, yeah, I just wanted to give an overview here that there's, there's quite a bit more out there in terms of emerging contaminants. Next slide.
one interesting recent development in terms of managing emerging contaminants is a substantial amount of funding that has been made available through the by part part, bipartisan infrastructure. A lot of the SBIR program which includes a substantial amount of money that's earmarked for addressing emerging contaminants, particularly focusing on P fast but not limited to ... in accordance with the documentation around this. So this funding is made available through state drinking water funds. $4 billion has been earmarked for this $800 million a year to be divvied up between the states as part of the drinking. Water funds eligible systems include public public, water supplies or private non-profit types of systems a lot more behind the scenes to that to look into if needed and also 25% indicated for disadvantaged communities.
There's a summary here on the right-hand side of what is considered eligible projects related to emerging contaminants? And I won't go through this in detail, but really the Big Picture is funding for a variety of types of projects involving assessment of impacts.
Implementing a system and designing and putting something into place a treatment may be needed and even training types of systems could be a part of this. Next slide.
Alright, so wrapping things up here. A common feature between all of these emerging contaminants that we've talked about and others on the list is like that they're useful. These are all chemicals that have been very widely produced because that's what people do. We find something useful and then make way too much of it. Don't find out It's a problem until we find out later. But typically, these contents of emerging concern or newly discovered chemicals that have been produced for awhile and we're still producing new chemicals. So whatever tomorrow's emerging emerging contaminants is going to be something we're still coming up with today. So it's a it's an ongoing process, of course. As we've talked about, conventional water treatment may not be designed for contaminants of emerging concern. For most of the seas, there's some technology out there that can be used to treat, but we just have to know, I have some data to know what we're looking for.
And systems can be designed and implemented accordingly regulations. So always, always, a step behind always tried to catch up with emerging contaminants. So it's it's an ongoing process following these speculations.
And then the final note here that we've touched on a very short list of countless chemicals that are present in the environment. So always a process to keep up with the emerging contaminants.
So that's that wraps up our presentation.
Thank you, Mitch, and Fritz, and Kyle, great information. We all know we could probably talk all day on these, are emerging contaminants. So appreciate you guys, pulling it together and providing a summary. We are up to our time. We did have one question about the slides being available after the presentation. And just want to let everybody know that, over the next couple of days, we will be sending a copy of the slide deck, as well as a recording of today's webinar. We did have one question come in for it, so I believe it's for you about it.
TCP bear with me one second With the widespread use of 1 2 3 TCP in agriculture.
Is it hard to distinguish impacts from a given site from a regional non point source, or sources? Excuse me.
Sure, I mean, the short answer is, yes, that is challenging. But, yes, it can be. It can be done. If you recall that, that patchwork plaque that I showed of just all the different application of this, this compound, and how heterogeneous it was there.
You know, you are over printing non point source issues that have been documented.
And the USGS and in combination with some California waterboard personnel have done some research into that.
So, there's some, some academic research out there for a conceptual model of what that, what that non point impacts might it might look like, how they're stratified with, with depth changing over time. So, quite a lot there, more than I can answer in this particular time, but it can be done, would be happy to converse on that's more with, with someone if they're, they're interested.
Thank you for it. I bet we could squeeze in one more question. For those of you that are submitting questions via the questions panel and keep in mind, we will answer your questions via e-mail, just because we're running a little bit short on time today. But we will make sure and send out your questions along with answers to you all individually. Let's go with one more and then we'll wrap it up. Do you know anything about graphene, a nano material, potentially becoming a CEC?
I've I've come across a instances. I think articles where that's been identified as as a contaminant but I do not know anything about the regulatory process.
I haven't seen it shown up on regulatory lists, doesn't mean it hasn't been available, it just hasn't been seen and on lists that I have been looking at.
Alrighty. Well, let's go ahead and wrap up for today. As I mentioned, we will answer any questions via e-mail after the webinar is concluded today. There will be a copy of the recording as well as a PDF of the presentations. We appreciate you taking time out of your day to spend with us today to learn about emerging contaminants.
And please don't forget to answer that brief survey at the exit of the webinar today is that helps us out shape our webinars in the future as well as provide you an opportunity to submit any topics you'd like to hear on for the future. So Mitch, Frit. Kyle, thank you so much.
Thank you, Amy. Thanks, everyone, for attending!