WEBVTT 616 00:00:00.360 --> 00:00:26.569 FRTR Presenter: All right, I think in the interest of time we'll carry on with our next presentation for those of you online. I see your questions hopefully. We'll have time to come back to them later on in our panel session at the end of our presentations today. So I want to thank everybody online. We do have about 600 individuals here who are live from all over. So thank you all for chiming in Kent. I'll turn the floor back to you. Yes, I'm here. 617 00:00:26.720 --> 00:00:43.520 FRTR Presenter: One more presentation, and we will end this morning, Marathon session with a break. It will be an entertaining and informative presentation. Right, Dennis. Absolutely so. Dennis Leblanc is our speaker. 618 00:00:43.630 --> 00:00:51.699 FRTR Presenter: Been a couple, 3, 4 years since you've been with us, but welcome back. He's a scientist emeritus. Now back then he was a 619 00:00:51.860 --> 00:00:55.709 FRTR Presenter: had a different title. But he's now a scientist emeritus at Usgs. 620 00:00:55.950 --> 00:00:58.560 FRTR Presenter: 48 year tenure at the Usgs. 621 00:00:58.720 --> 00:01:04.550 FRTR Presenter: Directing the Cape Cod toxic Substance hydrology research site 622 00:01:05.756 --> 00:01:21.220 FRTR Presenter: coordinated Usgs. Technical assistance to the groundwater cleanup at Joint Base, Cape Cod participated in nitrogen investigations in cooperation with the EPA conducted regional studies of groundwater resources. 623 00:01:21.781 --> 00:01:28.850 FRTR Presenter: Dennis has a Bs in hydrology from University of New Hampshire and an Ms. From 624 00:01:28.990 --> 00:01:32.500 FRTR Presenter: Mit in civil environmental engineering. So, Dennis. 625 00:01:37.730 --> 00:01:41.100 FRTR Presenter: thank you very much for the introduction. Can you all hear me? Okay. 626 00:01:41.460 --> 00:01:42.120 FRTR Presenter: right? 627 00:01:42.790 --> 00:01:46.290 FRTR Presenter: So, Cynthia, right in one of her very 1st slides 628 00:01:46.690 --> 00:01:53.260 FRTR Presenter: indicated that one of the pfas challenges is that many installations there are multiple sources. 629 00:01:53.360 --> 00:02:01.589 FRTR Presenter: and they're in a complex groundwater flow system. Oftentimes a groundwater surface water flow system. 630 00:02:01.690 --> 00:02:15.590 FRTR Presenter: The image you see on the left is an aerial view of the flight line area of Joint Base, Cape Cod, and you can see right up. Nestled against the southern boundary of the base are 2 glacial kettle lakes, the Air Force, afcac. 631 00:02:15.680 --> 00:02:37.190 FRTR Presenter: As early as 2018 realized that there were a number of potential pfas sources on the flight line area and just using the regional groundwater model they had available at the time they projected that those flow paths would travel southward off the base and intersect those glacial kettle lakes, and a stream with a wetland complex around it. 632 00:02:37.590 --> 00:02:58.379 FRTR Presenter: So afcac has focused much of its effort as is typical of the paradigm of investigating these kinds of things, putting in a lot of work, identifying sources, characterizing pfas in the groundwater and the soils near the sources, and then trying to determine the extent working outward from those sources of the Pfas occurrence. 633 00:02:58.590 --> 00:03:07.189 FRTR Presenter: The Usgs in the last 10 years has been really involved in looking at groundwater surface water interactions in this area for a variety of reasons. 634 00:03:07.200 --> 00:03:24.680 FRTR Presenter: And we thought maybe we could complement the afcac work by actually going down to the likely receptors that are receiving these. This pfas, as it discharges into surface waters and look at where it's coming out, and from that perhaps inform in a backwards direction. 635 00:03:24.680 --> 00:03:40.240 FRTR Presenter: the investigations that are taking place, upgrading it on the base, and also begin to get a really early thinking process going about where you might most effectively use remediation to reduce the exposure to these natural resources and to the people downstream. 636 00:03:41.770 --> 00:03:46.919 FRTR Presenter: So my talk today is just going to be a a discussion of ongoing work 637 00:03:46.940 --> 00:04:08.939 FRTR Presenter: applying a variety of methods or tools, mainly hydrologic ones, because that's what I am. I'm a hydrologist to differentiate the Pfas sources up on joint base Cape Cod to help guide the investigation of those sources, and, as I mentioned before, possibly start thinking about where remediation might be applied. 638 00:04:09.250 --> 00:04:16.120 FRTR Presenter: This work I'm shamelessly borrowing a lot of material from many of my Usgs colleagues noted on the left 639 00:04:16.370 --> 00:04:26.889 FRTR Presenter: lower left, and this work is a cobbling together of funding from afcac the from the joint Base Cape Cod program at afcac 640 00:04:27.070 --> 00:04:32.850 FRTR Presenter: an Esdcp project and the Usgs Environmental Health program. 641 00:04:34.380 --> 00:04:41.080 FRTR Presenter: First, st a bit about Cape Cod. Cape Cod is a permeable sand and gravel aquifer 642 00:04:41.230 --> 00:04:50.249 FRTR Presenter: located on in south southeastern Massachusetts. It's separated from the mainland by the sea level Cape Cod Canal. So it's an island. 643 00:04:50.320 --> 00:04:57.629 FRTR Presenter: The sand and gravel aquifer in the area near drunk Paste Cape Cod ranges from about 100 to 300 feet thick. 644 00:04:58.010 --> 00:05:11.430 FRTR Presenter: The upper boundary of the groundwater flow system is the water table. It's an unconfined aquifer, and where the land surface dips down and intersects the water table. Typically at these glacial kettles you can have these glacial kettle lakes. 645 00:05:11.710 --> 00:05:13.720 FRTR Presenter: the bottom boundaries bedrock. 646 00:05:13.950 --> 00:05:20.360 FRTR Presenter: Laterally the aquifer is bounded by a freshwater saltwater interface. But we're not going to talk about that today. 647 00:05:21.239 --> 00:05:33.789 FRTR Presenter: The water table makes a series of mounds on Cape Cod Joint base. Cape Cod is located on the westernmost mound, the tallest one gets up to a huge 70 feet above sea level. 648 00:05:34.345 --> 00:05:43.779 FRTR Presenter: And groundwater flows sort of radially outward from the tops of the mounds out toward the coast, or to discharge points along the way to either streams or lakes. 649 00:05:44.100 --> 00:05:50.030 FRTR Presenter: The groundwater flow rate is about one to 2 feet per day. So things are zipping along in the groundwater world here. 650 00:05:50.160 --> 00:05:54.939 FRTR Presenter: and the only source of water to the aquifer is recharge from precipitation. 651 00:05:56.080 --> 00:06:13.670 FRTR Presenter: The surface water features that will come up most in the talk are these glacial kettle lakes and the streams. The glacial kettles are, as I said, depressions in the land surface that intersect the water table. Many of them have no surface, inlet or surface outlet or small ones. 652 00:06:13.670 --> 00:06:38.099 FRTR Presenter: and so they're really groundwater in and lake water out, or what we call groundwater, flow through ponds where groundwater is discharging into the lake. On the upgrading side, lake water turns back into the aquifer by seeping through the lake bottom on the downgrading side, and because these lakes only partially penetrate the aquifer, there are also flow paths that may pass beneath the lake and not get up into it. 653 00:06:38.260 --> 00:06:48.739 FRTR Presenter: The streams are are groundwater dominated, and most of the flow in the streams comes from groundwater discharges. They're basically like drainage ditches drawing off water. 654 00:06:48.810 --> 00:06:55.469 FRTR Presenter: By the way, that image in the lower right is the wetland area. While it was still being farmed as a cranberry bog. 655 00:06:57.430 --> 00:07:22.690 FRTR Presenter: the contaminant plumes on joint base Cape Cod. Many of them have been. There are many plumes that have been very well documented. This happens to be just a plume from a wastewater disposal facility. You see, in the photo just located up gradient of a schumer pond. That's the plume mapped out using nitrate. This was a wastewater plume. My purpose in showing you this is only to show you that the plumes are elongated in the direction of groundwater flow. 656 00:07:22.690 --> 00:07:44.619 FRTR Presenter: and that they tend to have very sharp boundaries, especially in the vertical direction. And because there's recharge taking place from precipitation along the paths of the plumes. The plumes oftentimes are pushed down or depressed down below the water table, so there's often a clean layer, a zone of clean water above the plumes. When you get away from the sources. 657 00:07:45.068 --> 00:08:07.080 FRTR Presenter: The map on the right is a map of the various contaminant plumes that were known on Joint base Cape cod in 2,007. I only show it just to show you proof that the groundwater flows radially outward from the high point of the water table. So you have this like rose petal flower petal arrangement of the plumes heading to the south. 658 00:08:10.360 --> 00:08:25.150 FRTR Presenter: So our our pfas story starts in about 2,014, the fire training area one on the base. You see the photo on the left, taken from a helicopter in 1984, when it was active. 659 00:08:25.160 --> 00:08:36.010 FRTR Presenter: is located on the southern boundary of the base, upgrading it from the old wastewater treatment plant that you see the little green patch and then assume it pond in the in the distance, on the upper left. 660 00:08:36.801 --> 00:08:43.870 FRTR Presenter: the the fire training area was operated from about 1958 to 1985. 661 00:08:44.341 --> 00:08:52.709 FRTR Presenter: That's actually a photo historical photo of them fire training at the base. In one of these unlined facilities that was mentioned in the previous talk. 662 00:08:53.070 --> 00:09:14.289 FRTR Presenter: Andrea Weber. And now Andrea Tokronov did her Phd. Thesis work on mapping out the plume from the fire training area, and what she showed in the diagram in the lower left is. There was, indeed, a plume with very high concentrations of total pfas migrating from the fire training off to the southeast. 663 00:09:14.300 --> 00:09:40.500 FRTR Presenter: and certainly intersecting, or at least in Map View, intersecting a schumat pond, one of these groundwater flow through ponds. So right in the very beginning, a few years after she began her sampling. We went out, and the Air Force also did this. Afcac also did this and sampled the lake water, and it had total pfas concentrations. Over 200 nanograms per liter. So fairly contaminated surface water. 664 00:09:40.540 --> 00:09:48.569 FRTR Presenter: We pushed little well points into the lake bottom just offshore on the upgrading side, and sure enough, there was the plume coming in. 665 00:09:48.650 --> 00:10:07.110 FRTR Presenter: but we also noticed when we pushed the well points in and put in some multi-port wells in the downgrading side, that there was pfas downgrading to the lake in what we thought was clearly lake water. So the pfas in this groundwater flow through setting was being carried through the lake and then back down into the aquifer. 666 00:10:08.890 --> 00:10:32.119 FRTR Presenter: Now the implication of this dawned on us fairly quickly. The bad implication of this. I guess we had been doing a work. My colleague, Jk. Bulkey, who some of you know, who's here in Reston and I had been doing some work looking at the voc plumes, because, you know, back before 2014. Believe it or not, we weren't talking about pfas, and now we only talk about pfas 667 00:10:32.120 --> 00:10:48.150 FRTR Presenter: and what we discovered, or what we noted was that we could use stable isotopes of water, the Delta, O. 18, and the Delta H. 2. To actually look at lake water, which has an isotopically heavier water, because it's affected by evaporation 668 00:10:48.380 --> 00:11:03.430 FRTR Presenter: and contrast that with groundwaters that had never gone through a lake. And so, therefore they were what we call meteoric water, and that was isotopically lighter and actually identify in the aquifer where this water, leaving the lake seeping through the lake bottom was. 669 00:11:03.690 --> 00:11:11.840 FRTR Presenter: And that's a cross section that you see of profiles in the top of the slide. The map view shows you where those 670 00:11:11.970 --> 00:11:23.550 FRTR Presenter: profiles are located. It's a transverse cross section down gradient from a schumat pond, and the gray area is shading that area of isotopically heavier water 671 00:11:23.700 --> 00:11:36.560 FRTR Presenter: that indicates that it was coming out of the lake, and the what we call the lake shadow, or the lake water affected zone gets to be very thick, hundreds of feet thick on the down gradient side of a schumat pond. 672 00:11:36.940 --> 00:11:41.379 FRTR Presenter: and we also noticed that the vocs that the Air Force was tracking 673 00:11:41.460 --> 00:12:05.939 FRTR Presenter: only that we knew were intersecting the lake, and Mapview only showed up in the water downgrading to the lake below that lake water zone. That's because when they went into the lake they were lost by evaporation or some other process and removed. So the lakes were big treatment systems for the vocs. But there were these flow paths that passed beneath the lake, and they were delivering vocs past the lakes, and then it suddenly occurred to us. 674 00:12:06.060 --> 00:12:25.360 FRTR Presenter: Eureka, we have employment for the next 50 years. It turns out that the pfas stay in the lake, and that was a joke. Of course the pfas stay in the lake water, and so, therefore this very thick zone of lake water down gradient from the lakes likely has that pfas in it. 675 00:12:26.370 --> 00:12:31.099 FRTR Presenter: and that's indeed what we saw. We, we, the profiles on the left. 676 00:12:31.260 --> 00:12:37.939 FRTR Presenter: our downgrading of a Schumann and John's Pond, and you can see their location circled in red on the right 677 00:12:38.230 --> 00:12:40.563 FRTR Presenter: on the map, and that 678 00:12:41.380 --> 00:12:46.899 FRTR Presenter: The green zone is the zone of that isotopically heavier 679 00:12:47.090 --> 00:13:09.040 FRTR Presenter: what we identified as lake Water or the lake shadow, and you can see in the lower left of F. 655. The profile on the left is a little tiny blip of pfas, the blue line down below the lake shadow. On the other hand, the red profiles show you that there's pfas throughout the entire thickness, as we had hypothesized 680 00:13:09.742 --> 00:13:13.598 FRTR Presenter: in the lake water zone of of pfas. 681 00:13:14.520 --> 00:13:29.270 FRTR Presenter: So if you just used a hydrologic, simple analysis. You look at the water table, map down gradient of a Schumert pond and you just follow flow lines. It would suggest that that pfas is moving out in a vast plume. 682 00:13:29.520 --> 00:13:54.019 FRTR Presenter: downgrading it from a schumat pond that's shaded in blue in that map, and that everywhere in that area there should be lake water, and if there's been enough travel time, the pfas is expanding into that area so you can think of the lake almost as a lens that's taking a fairly small plume and then expanding it through a very large and thick zone. That map in the blue. On the in this the map on the left. 683 00:13:54.110 --> 00:14:05.680 FRTR Presenter: I just contrast with the map of the volatile organic or the vocs that was known just to show you the differences and the effect of the lake on the the fate of the Pfas. 684 00:14:06.960 --> 00:14:07.800 FRTR Presenter: so 685 00:14:07.950 --> 00:14:31.379 FRTR Presenter: subsequently afcac and the Usgs have done extensive sampling in that hypothesized blue area of the where we think the pfas should be because of the lake effect. And sure enough, the red dots in that map on the left show you that everywhere they sample in that area we're finding pfas, so that that hypothesis of this expanding zone because of the lakes is true. 686 00:14:31.400 --> 00:14:39.840 FRTR Presenter: and that has led to a proposed interim action that's actually being considered now by afcac and the Regulators 687 00:14:39.890 --> 00:14:58.149 FRTR Presenter: to go to where that fire training area plume 1st intersects the Schumat pond on its upgrading side and just put in a capture fence. There's a diagram in the proposed remedial action interim action that I took out of there put in a line of wells and capture that plume. Now. 688 00:14:58.500 --> 00:15:05.830 FRTR Presenter: you know, while you're trying to figure out what to do with the fire training area and all of its contaminated soils. Cut off the plume at the lake. 689 00:15:06.020 --> 00:15:19.450 FRTR Presenter: The lake will very quickly begin to lose concentrations, and therefore it won't continue to pump it out into the rest of the aquifer. So here's an example where thinking about surface water groundwater interactions might lead you to some 690 00:15:19.500 --> 00:15:26.480 FRTR Presenter: an action that maybe is not at the source, but is at some place where you can have an immediate effect on reducing exposures. 691 00:15:28.880 --> 00:15:44.940 FRTR Presenter: The other thing we began to look at was. And this is more recent work. What happens to all those plumes that are originating on the eastern part of the flight line that are up gradient of John's Pond and the Quashnet River and its wetlands that you see in the map. 692 00:15:45.040 --> 00:15:51.579 FRTR Presenter: That box outlined in red is that's the area of the aerial photo on the right 693 00:15:51.970 --> 00:15:59.370 FRTR Presenter: again, when Andrea and and her Usgs colleagues, along with afcac. 694 00:15:59.510 --> 00:16:06.839 FRTR Presenter: 1st realized that a Schumat pond was contaminated, and that because the Schumat Pond water goes to John's Pond, John's Pond's contaminated 695 00:16:07.318 --> 00:16:14.199 FRTR Presenter: that is probably affecting the Quashnut River, which has a direct outlet from John's Pond. 696 00:16:14.480 --> 00:16:43.290 FRTR Presenter: So what we did very early on in 2,007. And this is a diagram that shows you only Pfos and Pfoa, because that was the thing of the time. The 80 nanogram per liter limit. We looked at the stream, and the yellow dots show you the locations where our hydrographers went in and measured stream flow. There was some discharge directly from the pond, so right away at the at the outlet of the lake, there was flow in the stream, and the 697 00:16:43.590 --> 00:16:48.180 FRTR Presenter: the discharge is shown in green. There was a little bit of groundwater pickup 698 00:16:48.240 --> 00:16:56.850 FRTR Presenter: about through about halfway down the the course of the stream, through the cranberry bogs. The old cranberry bogs. Then there was a big increase in flow. 699 00:16:57.070 --> 00:17:12.399 FRTR Presenter: about 600 meters, and then it leveled off again and slightly increased, which indicated there was some groundwater input coming in being added. And then there's a small northern tributary to the north that adds quite a bit of flow, making it jump up. And then 700 00:17:12.450 --> 00:17:15.350 FRTR Presenter: a little bit of groundwater input going further to the south. 701 00:17:15.710 --> 00:17:19.869 FRTR Presenter: When you look at the P. Phos concentrations of the P. Phos plus pfoa. 702 00:17:19.940 --> 00:17:35.160 FRTR Presenter: which is the blue line, you see a significant increase in concentrations that drops at about 600 meters, and then actually drops a little bit more as you get down to a thousand meters. So it doesn't make any sense. 703 00:17:35.190 --> 00:17:41.850 FRTR Presenter: But it turns out that that Northern tributary has a lot of water, but low concentration. So it actually dilutes the water in the river. 704 00:17:41.910 --> 00:17:57.060 FRTR Presenter: So when you just take the flows in the river and the discharge, and you multiply them together, you can see from the red line that there's a significant increase in total mass. Load down the river as you go down river. That indicates that 705 00:17:57.400 --> 00:18:26.860 FRTR Presenter: there's a mass load coming out of the lake. It doesn't start at 0, but that mass load of much more than doubles almost a factor of, I'd say, 5 or so increasing by a factor of 5 or so as it goes through this wetland complex, really solid proof that these flight line sources are indeed producing contaminants, pfas that are following trajectories and intersecting the cranberry bog and the river, and increasing the flow. 706 00:18:26.930 --> 00:18:30.839 FRTR Presenter: increasing the total mass load. So we said, Well. 707 00:18:32.390 --> 00:18:42.479 FRTR Presenter: how can we take this this map? And now we, we know we have these flight line sources, potential paths. And we're going to focus in that lower right where the green is, where the cranberry bogs are. 708 00:18:42.900 --> 00:18:55.309 FRTR Presenter: while the afcac is working up gradient. Can we go down to where it's coming out? See where it's coming out, and then sort of inform in an upgrading direction what might be happening and what you might do about it. 709 00:18:56.400 --> 00:19:09.980 FRTR Presenter: So I'm going to go quickly through a series of techniques. This was a demonstration project that's still underway funded by Estcp. And then highly leveraged with Usgs and Afcac. Jbcc. Money as well. 710 00:19:10.473 --> 00:19:25.639 FRTR Presenter: the major tool we used early on to try to figure out where the groundwater is coming out is various kinds of temperature sensing. There are other methods we're using. But I won't go into them today, because these are nice visuals, and you can see right away what's happening. 711 00:19:25.810 --> 00:19:32.479 FRTR Presenter: It turns out that we can take advantage of the seasonal contrast in temperature between the surface waters and the groundwater. 712 00:19:32.530 --> 00:19:41.019 FRTR Presenter: In the middle of winter. The groundwater is the groundwater is pretty steady at about 50 degrees C. Or 1050°F, or 10 degrees C. 713 00:19:41.080 --> 00:19:44.699 FRTR Presenter: And of course the surface waters vary over a much larger range. 714 00:19:44.720 --> 00:19:46.429 FRTR Presenter: So in the winter 715 00:19:46.440 --> 00:19:54.711 FRTR Presenter: the warmer groundwater is coming in, and we can see that with infrared imagery this is imagery on the right from drone. Well, both from drones. 716 00:19:55.180 --> 00:20:02.730 FRTR Presenter: An initial bog, a wide survey by the town of Mashpee, and then a more focused effort by the Usgs on the left. 717 00:20:03.484 --> 00:20:13.339 FRTR Presenter: In the summertime you have the opposite. You have cold groundwater coming in, and you can see it using thermal images in the same way. 718 00:20:13.400 --> 00:20:27.859 FRTR Presenter: And so you see on the right. There are definitely areas of reds and yellows that indicate warmer. This is done in December. So you have areas of warmer groundwater coming in. There's also some interference with sun on the land and so forth. 719 00:20:27.930 --> 00:20:42.169 FRTR Presenter: On the left there's a zoomed in area of that box outlined in red of one area, a wetland that extends to the south that feeds to the north to the river, and you can see some very clear groundwater inputs 720 00:20:42.320 --> 00:20:51.849 FRTR Presenter: into the river, shaded in red where the warm groundwater, because this was done in March, is coming up into the surface waters, indicating some major groundwater discharges. 721 00:20:54.037 --> 00:21:15.240 FRTR Presenter: Because when the warm groundwater goes into the river, or the stream, or the ditch in the bog, it tends to flow along with the flow. It'll tend to exaggerate where the water's coming in. So you know, it came in at a point, and you kind of like have a tail that goes off in the direction of flow. So we also used handheld infrared cameras to locate 722 00:21:15.240 --> 00:21:34.870 FRTR Presenter: of specific seeps, and sometimes they weren't visible because of vegetation. You can see 2 people there locating a seep. The upper image on the right is the regular photograph, and then the lower one is the same image, using infrared imagery, showing you that much warmer water coming in. 723 00:21:36.760 --> 00:21:59.150 FRTR Presenter: and then to verify that even further, we used handheld probes, a temperature probe that we went to some of these seeps that have been identified by the infrared imagery, but also other places where you could just see something that looked like a seep that hadn't been caught. This is Marty Briggs with the Usgs out there with his temperature probe that he stuck in the bottom. 724 00:21:59.150 --> 00:22:18.949 FRTR Presenter: and on the right is a map that shows some what we call high temperature. Contrast seeps that were located along the course of the river, and also in the drainage system of the former cranberry bog that, by the way, is now returning naturally to a somewhat of a forested wetland. 725 00:22:20.360 --> 00:22:48.999 FRTR Presenter: So we selected a small number of these seeps. This is data only from our March Survey March 2020, and went in and used small push. Point Wells pushed them into the flagged seep that you saw the people flagging in the previous couple of images and pumped water from there and analyzed it for pfas, and these are total pfas concentrations shown at those seeps on the lower and the on the left. 726 00:22:49.110 --> 00:23:09.510 FRTR Presenter: and you can see that where there were definitely a fair number of seeps that were identified that were clearly flowing, based on the temperature contrast that had elevated levels of total pfas, including several that were up over a thousand nanograms per liter. So even though we're fairly far from the base. These plumes seem to be persisting that far. 727 00:23:10.430 --> 00:23:11.320 FRTR Presenter: Now 728 00:23:11.500 --> 00:23:37.360 FRTR Presenter: we can begin to group these things and try to understand the nature of them. This is a fairly simple diagram actually, on the upper, on the top. You see, we've divided the samples from these seeps into 2 bins less than 200 nanograms per liter, and greater than 350 nanograms per liter. I don't know what happened between those 2 numbers, but maybe I guess no samples fell there. 729 00:23:38.171 --> 00:23:42.680 FRTR Presenter: And you can see that there's definitely both types. 730 00:23:43.579 --> 00:23:50.409 FRTR Presenter: On the X-axis we have that isotopic signature of the seepwater sample. 731 00:23:50.640 --> 00:24:08.459 FRTR Presenter: and the top pair of boxes are isotopically heavier water that indicates one of these lake effects. This suggests that the water coming out of the seep has been influenced by evaporation from a lake that's up gradient, and it turns out there is a lake up gradient, a small one. You'll hear about Moody Pond. 732 00:24:08.639 --> 00:24:17.309 FRTR Presenter: and the lower pair of panels are isotopically light water that looks like it's strictly a groundwater flow path from a source directly to the seep. 733 00:24:17.340 --> 00:24:23.290 FRTR Presenter: So you can clearly see there's this division of different types of seeps that fall into bins. 734 00:24:23.618 --> 00:24:27.760 FRTR Presenter: And you know, the question is, where are those in the landscape? 735 00:24:28.700 --> 00:24:35.739 FRTR Presenter: And so I've taken those exact same spots and plotted them here. And it's kind of eye-opening they actually start to fit together. 736 00:24:35.799 --> 00:24:56.539 FRTR Presenter: The blue triangles that are also surrounded by the dashed circles are those that had less than 20 nanograms per liter. Of the Massachusetts maximum contaminant level pfas, 6 compounds that the joint base Cape Cod team is using as its guiding limit. 737 00:24:56.590 --> 00:25:23.510 FRTR Presenter: There are definitely a fair number of seeps that had little Pfos and looked a lot like a meteoric groundwater, some that had a little or low pfas, and looked more like turfish waters, but you see there are a fair number of seeps all clustered together for the most part that look like they have very high pfas, and also seem to be affected by this evaporation in a glacial kettle Lake, and you'll notice they're all 738 00:25:23.510 --> 00:25:41.159 FRTR Presenter: clustered together directly down gradient of Moody Pond. So perhaps that's Moody Pond Water heading off toward that area. On the other hand, there are some others with high pfas that look more like groundwaters. They look like they must have passed along flow paths that didn't get directly to the lake. 739 00:25:41.379 --> 00:25:44.309 FRTR Presenter: So we have definitely indication that there's different 740 00:25:45.190 --> 00:25:48.209 FRTR Presenter: paths taking the pfas from the base 741 00:25:48.219 --> 00:25:50.100 FRTR Presenter: to the the river. 742 00:25:50.270 --> 00:25:59.700 FRTR Presenter: So in 2,000 late, 2,022, and we did some more work. In 2023 we went in and installed a 743 00:25:59.770 --> 00:26:12.200 FRTR Presenter: a fence of multi-port monitoring wells along the upgrading edge of the cranberry bog and river system along that line you see there in red, and you can see the sites. 744 00:26:12.219 --> 00:26:25.310 FRTR Presenter: And so we're intersecting the flow as it's coming in from the north from Joint Base, Cape Cod, and also from whatever's happening as that groundwater passes through this groundwater flow through Pond called Moody Pond. 745 00:26:28.610 --> 00:26:39.450 FRTR Presenter: and I'm going to just show you a series of profiles. I love profiles. These, again, are from permanent multi-port wells, so we can go back and resample these as we wish. 746 00:26:39.956 --> 00:26:45.370 FRTR Presenter: I've just shown you 3 examples. They're circled in red there on the map. 747 00:26:45.887 --> 00:26:51.700 FRTR Presenter: And I've shaded the profiles very lightly and hopefully. You can see that 748 00:26:51.790 --> 00:27:09.940 FRTR Presenter: to just help you focus on individual zones. The black line is the isotopes, and to the right is heavier, which means it's more like lake water. The red is the pfas, and this is the Mmcl. Pfas. 6 concentration, and then I also included nitrate. 749 00:27:09.980 --> 00:27:30.530 FRTR Presenter: And you say, why nitrate? Well, we're using a variety of chemical tools. One thing that does drive me nuts a little bit is we're going to study Pfos. So we analyze pfas, we're going to study vocs. So we only analyze vocs. And there are all these other chemical signatures that can be used to help figure out what's going on. In this case we use the isotopes and the nitrate. 750 00:27:30.830 --> 00:27:45.599 FRTR Presenter: What you see in the upper panel is the water's slightly heavier isotopically. So I'm going to just tell you that those purple zones are waters that we think are probably lake water affected. And you can see there's this elevated pfas there. 751 00:27:45.670 --> 00:27:49.570 FRTR Presenter: Then, when you get down into the greenish zone below that 752 00:27:49.760 --> 00:28:08.379 FRTR Presenter: that's isotopically lighter water, indicating direct groundwater flow paths from sources to the fence. And you see there's another zone that's consistent in all 3 profiles of elevated pfas, getting up over 600 nanograms per liter. So so quite high. 753 00:28:08.400 --> 00:28:16.730 FRTR Presenter: I just note that Moody Pond has about 400 nanograms per liter turns out to be the most contaminated surface water near Joint Base, Cape Cod 754 00:28:17.251 --> 00:28:22.530 FRTR Presenter: and so there are concentrations in the downgrading groundwater that are significantly higher than that. 755 00:28:22.910 --> 00:28:29.119 FRTR Presenter: Then you get down into the nitrate zone or that yellow zone that's areas where it looks like 756 00:28:29.220 --> 00:28:36.380 FRTR Presenter: isotopically light water. So therefore not affected by the lakes, and it has elevated nitrate. But there's no pfas there. 757 00:28:36.470 --> 00:28:39.109 FRTR Presenter: So we begin to have this notion of a layer cake 758 00:28:39.370 --> 00:28:44.120 FRTR Presenter: of of waters that are telling us something about what's arriving there. 759 00:28:45.516 --> 00:28:59.049 FRTR Presenter: We have also begun to look at the Pfas composition. I just am showing you these 3 profiles here on the right circled in red, just to show you the contrasts 760 00:28:59.160 --> 00:29:25.929 FRTR Presenter: you'll notice in the on the left panel, which is right near the outflow from John's Pond. There's isotopically heavier water, with very high concentrations of pfas up over around 400 nanograms per liter. And interestingly, in that area there there's also elevated Pf, and A, which is the only area where we see this in the entire study is up on that western side, near John's Pond. 761 00:29:26.595 --> 00:29:31.150 FRTR Presenter: As we go a little bit, and then on the panel on the right. 762 00:29:31.230 --> 00:29:46.670 FRTR Presenter: Oh, as you go a little bit deeper in that profile on the left. You also see that we're beginning to be in waters that look like they're not going through a lake, and there are very high pfas concentrations there, and we see elevated Pfhx down there. 763 00:29:47.065 --> 00:29:53.130 FRTR Presenter: You'll notice that pfas is very high, too, very high. Gets up almost to 3,000, I think, at that location 764 00:29:53.300 --> 00:29:56.640 FRTR Presenter: in the middle panel, the isotopically 765 00:29:56.640 --> 00:30:26.570 FRTR Presenter: light, heavy water that indicates it went through a lake. The predominant pfas there in green is pfhx, which is the green. The yellow is the pfas is a little bit lower, and then when you get into the lighter isotopic water indicating direct flow paths from the base. It turns out that the peak is dominated by pfas, not by pfhxs, so we can begin to see, possibly indications of different types of transformations, or even different sources as we go vertically. 766 00:30:26.840 --> 00:30:34.719 FRTR Presenter: and then the profile on the right shows you again. High Pfh, excess shallow 767 00:30:34.820 --> 00:30:39.689 FRTR Presenter: more than Pfos, and then it flips around when you get down to the deeper zone. 768 00:30:39.830 --> 00:30:47.060 FRTR Presenter: We're in the process of just trying to tease that out. So I can't talk anymore about that at this point, but you know we're looking at that as well. 769 00:30:48.499 --> 00:31:11.929 FRTR Presenter: I did want to make one additional point about vertical detail or level of detail. This profile is just about in the middle of the area, directly down gradient from Moody Pond. The photo on the right is the seep that's literally a few feet from this well, just off the edge of the land, down into the drainage ditch, and that seep has elevated pfas coming into it. 770 00:31:12.512 --> 00:31:22.820 FRTR Presenter: The profile on the left is is, you know, goes through a large vertical distance from about 40 feet above sea level, down to about 120 feet below sea level. 771 00:31:22.870 --> 00:31:25.920 FRTR Presenter: and I just zoomed in to the area. 772 00:31:26.220 --> 00:31:48.950 FRTR Presenter: the vertical interval between about 50 feet and minus 20 feet, where we put in an additional multi-port. Well, but in this case the ports are literally spaced a few centimeters apart in some areas, and what you see if you contrast the area on the left to the area on the right is that as you begin to drill down to finer and finer scales, you see more and more detail, and, in fact, the profile on the left 773 00:31:49.240 --> 00:31:56.460 FRTR Presenter: had spacing that was wide enough that it totally missed a really high concentration zone of p. 5 s. It's only about 10 feet thick. 774 00:31:56.500 --> 00:32:11.319 FRTR Presenter: That's in the transition dome between isotopically light and isotopically heavy water. So where is this leading us? Well, this is work in progress. We have 3 different journal articles in the works right now. 775 00:32:11.390 --> 00:32:17.180 FRTR Presenter: but we're beginning to put the picture together. So here's the profile. Here's the line of profiles on the left. 776 00:32:17.230 --> 00:32:24.160 FRTR Presenter: And you remember there were different seeps. And on the right, we've just created a cross section from that and begun to color code. It 777 00:32:24.310 --> 00:32:28.580 FRTR Presenter: just general characteristics. This blue zone is 778 00:32:28.620 --> 00:32:35.269 FRTR Presenter: high pfas, heavy isotopes looks like lake water, probably potentially lake water coming from Moody Pond. 779 00:32:35.570 --> 00:32:46.580 FRTR Presenter: Below that there's a thick zone of pfas in water that looks like it didn't go through the lake, so it's probably direct flow paths from the flight line without passing through Moody pond. 780 00:32:46.940 --> 00:32:52.149 FRTR Presenter: The yellow area is that area where it looks a lot like the orange area. But we have this pf, and A in it. 781 00:32:52.580 --> 00:32:57.370 FRTR Presenter: Then we have this zone. Purple zone with isotopically light water. 782 00:32:57.460 --> 00:33:00.540 FRTR Presenter: direct flow pass, and that's where the high nitrates are. 783 00:33:00.620 --> 00:33:06.130 FRTR Presenter: And then below that we won't go into the green zone. That's a bit of a mystery zone that we're starting to sort out at this point. 784 00:33:08.140 --> 00:33:11.140 FRTR Presenter: So what's our conceptual model that we're developing? 785 00:33:11.200 --> 00:33:21.219 FRTR Presenter: So there's the same profile cross-section, you see, and on the lower panel you see a cartoon diagram that's a transverse or along a flow path, cross section from the base. 786 00:33:21.300 --> 00:33:37.870 FRTR Presenter: What we think is, there are Air Force, Aaf release sites that are close enough to Moody Pond that they're discharging into Moody Pond. That's why Moody Pond. Sp. Then that moody pond water is leaving and going off and discharging into the river. That was that lighter zone right at the very top. 787 00:33:37.920 --> 00:33:40.289 FRTR Presenter: Then there are sources that are further back 788 00:33:41.030 --> 00:33:52.600 FRTR Presenter: or off to the side, so that they don't discharge the moody pond, and they deliver pfas at higher concentrations, for the most part directly to seeps and various seeps along the river. 789 00:33:52.660 --> 00:34:10.179 FRTR Presenter: and then, if you go upgrading it from joint base Cape Cod, you have pretty intense residential development, and that's the source of the nitrates from wastewater disposal through septic systems. That's underneath the whole pfas layer cake. So we have, like a Tiramisu here. If you want to think of it that way, or a layer cake. 790 00:34:10.589 --> 00:34:15.379 FRTR Presenter: That that we're beginning to see. And also I circled and ran on the panel 791 00:34:15.400 --> 00:34:20.849 FRTR Presenter: the places where the pfas concentrations were greater than a thousand nanograms per liter. 792 00:34:21.020 --> 00:34:43.379 FRTR Presenter: So we not only have this layer cake from different sources, but we're beginning to see also hotspots. And so when you begin to put that on a map like I did on the very on the left. That shows you red flow lines indicating flow paths to these hotspots, and you'll notice that one of the flow lines in the very middle. There's an arrow that ends at Moody Pond, then comes out of Moody Pond. So we have these these different paths. 793 00:34:43.790 --> 00:34:52.750 FRTR Presenter: and so that might lead us, therefore, as we begin to go back to the source map that afcac put together in 2018 and say. 794 00:34:52.890 --> 00:35:11.130 FRTR Presenter: you know, potentially, you have these really high concentration flow paths, some close to the Moody Pond some further that are delivering these pfas, and you might want to think about focusing your site investigations there, instead of hunting and pecking sort of randomly along the flight line, and also, if you want to stop discharge 795 00:35:11.520 --> 00:35:21.999 FRTR Presenter: to potential receptors, then you might want to begin to look at these seeps and where they're coming out as places to focus. You know how you design a remediation system. 796 00:35:22.550 --> 00:35:38.130 FRTR Presenter: So my concluding thoughts are that groundwater surface water interactions are very cool, I think, and they can really affect the fate and the paths of contaminant plumes, and that spatially detailed sampling of groundwater 797 00:35:38.160 --> 00:35:57.590 FRTR Presenter: near surface water receptors can really help guide up gradient site investigations, and possibly even help the thinking about what to do in terms of releasing exposures I mentioned. There are 3 reports that are being prepared on these findings. We've shared the results through tier. One meetings, I guess we call them 798 00:35:57.700 --> 00:36:11.259 FRTR Presenter: with with afcac, of course, and we actually have another project that we've begun where we're doing a very finely scaled or gridded 3D. Model particularly focused around the cranberry bogs and the river and the seeps 799 00:36:11.330 --> 00:36:14.620 FRTR Presenter: to try to better understand these groundwater flow paths. 800 00:36:14.720 --> 00:36:21.680 FRTR Presenter: So I hope you enjoyed that, and thank you very much for paying attention, knowing that I was the only thing between you and the break. 801 00:36:23.240 --> 00:36:25.430 FRTR Presenter: Well, thank you. Let's give him a round of applause. 802 00:36:27.770 --> 00:36:31.719 FRTR Presenter: All right. I'm seeing hands in the room. So the gentleman at the front. 803 00:36:33.410 --> 00:36:34.149 FRTR Presenter: Yep, you. 804 00:36:35.300 --> 00:36:53.439 FRTR Presenter: Dennis, thank you. I've been a fan of your work, even through your Estcp work. I guess I had a question. You know, I know you're the hydrogeologist looking at pathways, but thinking back to how this is going to ultimately cut these pathways off. 805 00:36:53.450 --> 00:36:58.139 FRTR Presenter: If you start to take the traditional groundwater pump and treat system. 806 00:36:58.610 --> 00:37:02.119 FRTR Presenter: And you start up trying to eliminate these pathways. 807 00:37:02.380 --> 00:37:14.759 FRTR Presenter: Do you have any thoughts on how that will impact the actual hydrology of these systems and the ecology that currently is there and might not be impacted by the pfas that are actually going there. 808 00:37:15.190 --> 00:37:17.414 FRTR Presenter: That's a really good question. 809 00:37:18.100 --> 00:37:18.630 FRTR Presenter: the 810 00:37:19.310 --> 00:37:34.770 FRTR Presenter: you know the Jbcc teams over the years have have wrestled with this whole idea of hydrologic balance, and in fact, the criteria were developed where they couldn't change the lake level by a certain amount. That kind of thing. So you're right as you get to some of these discharge areas. 811 00:37:35.090 --> 00:37:40.719 FRTR Presenter: You know you, you don't want to impact the surface water. So, for example, at a Shuman pond, this, the 812 00:37:40.740 --> 00:37:52.470 FRTR Presenter: interim action they're proposed pros, and to cut off that plume would involve reinjecting the water in areas that would put the water back into the lake. Okay, I think it gets a lot dicier when you get to a wetland. 813 00:37:52.500 --> 00:37:59.180 FRTR Presenter: You know you're not going to go seep by seep. That's not going to happen. So you might have to go up gradient some distance 814 00:37:59.210 --> 00:38:12.810 FRTR Presenter: and cut them off. You know, further upgrading. I think that you know it's pretty clear you're not going to put offensive wells that cuts off all the flow, leaving Joint base Cape Cod, you'd be treating vast quantities of water. And so you're going to have to like. 815 00:38:12.990 --> 00:38:27.010 FRTR Presenter: Go to some of these hotspot plumes that you say this one connects to this connects to that, and that's what's putting so much mass into the into the river. Let's cut that small area off, and then put that water elsewhere. It turns out 816 00:38:27.200 --> 00:38:27.900 FRTR Presenter: that 817 00:38:28.850 --> 00:38:29.790 FRTR Presenter: the 818 00:38:30.000 --> 00:38:35.869 FRTR Presenter: town, and the the State, and some Ngos are talking about 819 00:38:35.930 --> 00:38:43.430 FRTR Presenter: restoring a natural wetland. And into this system, and they're going to go in and completely dig it up and change the hydrology anyways. 820 00:38:43.440 --> 00:38:55.169 FRTR Presenter: And you know we just attended a meeting. That sort of just said, you do know there's a lot of pfas going in there, and that, you know, if you mess with this plumbing you got to keep in mind that you're not messing up the ability to remediate it. 821 00:38:55.370 --> 00:39:02.250 FRTR Presenter: So you know it goes both ways. But you know you've you've you've hit upon a problem for sure. Thank you. 822 00:39:03.420 --> 00:39:06.319 FRTR Presenter: I see another question at the table. 823 00:39:08.430 --> 00:39:11.359 FRTR Presenter: Very interesting talk. So. 824 00:39:13.280 --> 00:39:16.540 FRTR Presenter: Oh, I'm sorry. Here, I'm gonna give you the handheld 825 00:39:17.120 --> 00:39:19.170 FRTR Presenter: for some reason I'm not picking that one up. 826 00:39:19.680 --> 00:39:44.049 FRTR Presenter: Okay, yeah. Very interesting talk. I'm sorry if I'm ignorant on the Isotope analysis. And how you are comparing it with the pfas levels. Right? So you're comparing, taking the heavier isotope, which is oxygen and comparing it with the pfas levels. So my thought process is because. 827 00:39:44.400 --> 00:40:07.279 FRTR Presenter: comparing it with the pfas. If there are other co-contaminants present in, there might have some interference there in actually looking at the isotope patterns and the pfas. So how about looking at some of the shorter isotopes like a hydrogen one which you have shown also in your earlier slides. 828 00:40:07.290 --> 00:40:20.769 FRTR Presenter: taking that and comparing with the pfas levels, because now pfas is all fluorinated, so might have a very less interference in there. But I'm really, as I said, I don't know how these isotope patterns work. 829 00:40:21.380 --> 00:40:24.046 FRTR Presenter: So it was hard for me to hear. 830 00:40:25.100 --> 00:40:38.210 FRTR Presenter: So you're saying, should we be looking at other isotopes like hydrogen. Yeah, yeah, we. We're we're definitely doing Delta O 18, and Delta H 2, you know. So we're looking at the 2 isotopes on the water molecule is what we're looking at. 831 00:40:39.086 --> 00:40:54.289 FRTR Presenter: So we're not. You know. We're looking at the gastopic conversation of the water which is affected by the evaporation. And we do look at both. We also look at what's called a deuterium excess, which is, which is a deviation from the meteoric waterline of the isotopes, which are pretty standard techniques. 832 00:40:55.960 --> 00:40:59.540 FRTR Presenter: I you know I I can't. I can't expand beyond that. 833 00:41:00.070 --> 00:41:04.110 FRTR Presenter: you know. Maybe we could talk later, and I could understand your question a little bit better. Thank you.