1 00:00:00,000 --> 00:00:01,976 [SQUEAKING] 2 00:00:01,976 --> 00:00:04,446 [RUSTLING] 3 00:00:04,446 --> 00:00:05,434 [CLICKING] 4 00:00:14,820 --> 00:00:16,320 JOHN DOLHUN: Good morning, everyone. 5 00:00:16,320 --> 00:00:19,840 And welcome, or good afternoon. 6 00:00:19,840 --> 00:00:23,130 Welcome to The Ellen Swallow Richards Lecture Series. 7 00:00:29,350 --> 00:00:32,320 This is our beloved Charles River. 8 00:00:32,320 --> 00:00:35,530 This is the river you're going to be testing. 9 00:00:35,530 --> 00:00:38,770 Once you've tested this river, you 10 00:00:38,770 --> 00:00:42,550 can actually take this testing and apply it 11 00:00:42,550 --> 00:00:45,500 to any body of water. 12 00:00:45,500 --> 00:00:49,130 Why should we be concerned about this Charles River? 13 00:00:53,840 --> 00:00:54,340 Yes? 14 00:00:54,340 --> 00:00:56,290 Because we live next to it. 15 00:00:56,290 --> 00:00:58,900 Because we live-- that's a good reason. 16 00:00:58,900 --> 00:01:00,430 Because we live next to it. 17 00:01:00,430 --> 00:01:01,300 Anyone else? 18 00:01:04,150 --> 00:01:05,100 Aisha? 19 00:01:05,100 --> 00:01:06,985 AUDIENCE: To care about your environment. 20 00:01:06,985 --> 00:01:08,860 JOHN DOLHUN: You care about your environment. 21 00:01:08,860 --> 00:01:14,080 And speaking of caring about your environment, 22 00:01:14,080 --> 00:01:18,130 we've got some problems with phosphate out there. 23 00:01:18,130 --> 00:01:27,990 We've got high phosphorus concentrations. 24 00:01:27,990 --> 00:01:30,420 And those high phosphorus concentrations 25 00:01:30,420 --> 00:01:34,020 lead to algal blooms. 26 00:01:41,230 --> 00:01:56,125 And those algal blooms produce toxic chemicals and odors. 27 00:02:00,610 --> 00:02:06,040 And when all this algae dies, it heads down to the bottom 28 00:02:06,040 --> 00:02:10,980 and breaks off and it's acted on by decomposers. 29 00:02:10,980 --> 00:02:14,350 These microbes start to chew it apart 30 00:02:14,350 --> 00:02:19,510 and they use up the dissolved oxygen so that we get lower-- 31 00:02:26,240 --> 00:02:29,780 lower dissolved oxygen in the water. 32 00:02:29,780 --> 00:02:33,505 And what that does is it leads to fish kills. 33 00:02:40,990 --> 00:02:43,720 And our recreational ability is impaired. 34 00:03:02,660 --> 00:03:06,890 So here are some examples of what I'm talking about. 35 00:03:06,890 --> 00:03:10,150 This is Florida, 2016. 36 00:03:10,150 --> 00:03:14,380 This is Lake Okeechobee, one of the largest fresh water lakes 37 00:03:14,380 --> 00:03:15,620 in Florida. 38 00:03:15,620 --> 00:03:19,540 This is a 30 mile long fish kill. 39 00:03:19,540 --> 00:03:23,890 It involves some 50 species of fish. 40 00:03:23,890 --> 00:03:27,760 The cause, most probably, an algal bloom, 41 00:03:27,760 --> 00:03:31,960 the result of leaking septic systems, 42 00:03:31,960 --> 00:03:36,250 fertilizers from lawns going into the water. 43 00:03:36,250 --> 00:03:38,390 This is an economic disaster. 44 00:03:38,390 --> 00:03:42,100 It's going to take decades to recover from this. 45 00:03:42,100 --> 00:03:44,860 Is Bradenton, Florida, 2018. 46 00:03:44,860 --> 00:03:49,650 This is their harbor filled with dead fish. 47 00:03:49,650 --> 00:03:54,870 This started from an algal bloom that turned into a red tide. 48 00:03:54,870 --> 00:03:58,440 And the red tide stretched about 150 miles 49 00:03:58,440 --> 00:04:02,040 off the coast of Florida, and gradually, 50 00:04:02,040 --> 00:04:05,850 the wind and the currents brought it into shore. 51 00:04:05,850 --> 00:04:07,950 And when that red tide came in to shore, 52 00:04:07,950 --> 00:04:12,450 it started releasing toxins into the air and water, 53 00:04:12,450 --> 00:04:17,459 and then the nutrients broke off and microbes 54 00:04:17,459 --> 00:04:20,339 started digesting them and used up the oxygen, 55 00:04:20,339 --> 00:04:23,110 and all these fish died. 56 00:04:23,110 --> 00:04:26,740 This is Australia, 2019. 57 00:04:26,740 --> 00:04:30,970 This is the Darling River, but it also happened in 58 00:04:30,970 --> 00:04:32,230 the [INAUDIBLE] River. 59 00:04:32,230 --> 00:04:36,040 And they had a successive run of these fish kills, 60 00:04:36,040 --> 00:04:38,420 one right after the other. 61 00:04:38,420 --> 00:04:41,590 Again, it's global hot temperatures 62 00:04:41,590 --> 00:04:45,710 and agricultural runoff. 63 00:04:45,710 --> 00:04:50,090 This is the Charles River, August, 2019. 64 00:04:50,090 --> 00:04:52,850 This is the largest algal bloom, I think, 65 00:04:52,850 --> 00:04:54,770 that we've had out there. 66 00:04:54,770 --> 00:04:57,770 It actually stretched from the BU bridge 67 00:04:57,770 --> 00:05:00,110 to the Museum of Science. 68 00:05:00,110 --> 00:05:03,290 And cyanobacteria was detected. 69 00:05:03,290 --> 00:05:07,690 This is a health problem. 70 00:05:07,690 --> 00:05:12,890 So we're going to be measuring phosphorus in the waters 71 00:05:12,890 --> 00:05:13,470 out here. 72 00:05:13,470 --> 00:05:15,600 That's one of the things we're going to do. 73 00:05:15,600 --> 00:05:18,320 And there are two types of phosphorus, 74 00:05:18,320 --> 00:05:23,660 there's the inorganic, which is simply 75 00:05:23,660 --> 00:05:26,450 salts of phosphoric acid, and then 76 00:05:26,450 --> 00:05:29,060 if you create esters of the inorganic form, 77 00:05:29,060 --> 00:05:32,390 you have the organic form of phosphate. 78 00:05:36,380 --> 00:05:38,150 So let's take a look for a moment 79 00:05:38,150 --> 00:05:41,150 at the inorganic phosphate. 80 00:05:41,150 --> 00:05:45,320 I mean, phosphorus is like, the 11th most abundant element 81 00:05:45,320 --> 00:05:47,280 on the planet. 82 00:05:47,280 --> 00:05:50,330 And it's not found in elemental form. 83 00:05:50,330 --> 00:05:55,230 You won't find any pure phosphorous anywhere 84 00:05:55,230 --> 00:05:56,490 on the Earth. 85 00:05:56,490 --> 00:06:01,470 It's found in these types of phosphates, in rocks and soils, 86 00:06:01,470 --> 00:06:04,390 and that's how it exists. 87 00:06:04,390 --> 00:06:09,060 So the main inorganic player here is the orthophosphate. 88 00:06:16,800 --> 00:06:20,580 And that's the PO4 to the 3 minus. 89 00:06:20,580 --> 00:06:24,900 This is the most stable form of phosphorus. 90 00:06:24,900 --> 00:06:29,460 And this is the form that's readily available to plants 91 00:06:29,460 --> 00:06:31,800 for uptake by the plants. 92 00:06:31,800 --> 00:06:37,470 I mean, all plants and animals need phosphorus for growth. 93 00:06:37,470 --> 00:06:43,050 It's the backbone of our DNA and the Krebs cycle. 94 00:06:43,050 --> 00:06:44,940 Plants need it in photosynthesis. 95 00:06:44,940 --> 00:06:47,340 They have to extract it from their environment 96 00:06:47,340 --> 00:06:50,280 because they're not going to make sugar unless they first 97 00:06:50,280 --> 00:06:54,540 make ATP to actually connect those bonds in the sugars 98 00:06:54,540 --> 00:06:58,060 that they're making. 99 00:06:58,060 --> 00:07:01,590 So we've got this orthophosphate, the main player 100 00:07:01,590 --> 00:07:04,800 here, but in the inorganic category, 101 00:07:04,800 --> 00:07:06,720 you can actually connect several of these 102 00:07:06,720 --> 00:07:09,780 together and form a polyphosphate, 103 00:07:09,780 --> 00:07:11,460 such as our detergents. 104 00:07:11,460 --> 00:07:14,580 A lot of detergents are polyphosphates. 105 00:07:14,580 --> 00:07:21,150 P3O10 to the 5 minus would be a polyphosphate. 106 00:07:21,150 --> 00:07:23,460 The interesting thing about the polyphosphates 107 00:07:23,460 --> 00:07:29,400 is as soon as they hit the water, 108 00:07:29,400 --> 00:07:32,480 they hydrolyze into the orthophosphate. 109 00:07:43,840 --> 00:07:48,400 And then we've got the organic phosphates, 110 00:07:48,400 --> 00:07:51,520 which are esters of the inorganic form. 111 00:07:51,520 --> 00:07:58,370 And organic phosphates are found in all living tissues. 112 00:07:58,370 --> 00:08:06,870 So all living tissues, both plants and animals, 113 00:08:06,870 --> 00:08:09,690 have organic phosphates. 114 00:08:09,690 --> 00:08:15,630 And waste is also another form of the organic phosphates. 115 00:08:21,100 --> 00:08:26,290 So when something living dies, it starts to decay. 116 00:08:26,290 --> 00:08:31,060 What happens is the phosphates actually 117 00:08:31,060 --> 00:08:34,510 convert to the orthophosphate. 118 00:08:34,510 --> 00:08:37,970 That's what happens to them. 119 00:08:37,970 --> 00:08:40,450 So this is what we're going to be measuring. 120 00:08:40,450 --> 00:08:44,860 And now, I'd like to talk for a few minutes about how 121 00:08:44,860 --> 00:08:49,440 it gets into the water, where all this stuff is coming from. 122 00:08:49,440 --> 00:08:52,100 So we're going to look at some of the primary sources 123 00:08:52,100 --> 00:08:53,690 of the phosphorus. 124 00:08:58,740 --> 00:09:00,570 The first one is storm water runoff. 125 00:09:10,610 --> 00:09:17,810 Can anyone give me an example of some phosphoruses, phosphates 126 00:09:17,810 --> 00:09:20,285 that can get into the water from storm water runoff? 127 00:09:28,490 --> 00:09:29,307 Yes, Aisha. 128 00:09:29,307 --> 00:09:33,590 AUDIENCE: I'm not sure if there's a phosphate in dirt. 129 00:09:33,590 --> 00:09:34,590 JOHN DOLHUN: Absolutely. 130 00:09:34,590 --> 00:09:36,360 There's phosphate in the dirt. 131 00:09:36,360 --> 00:09:39,420 And that would get washed in. 132 00:09:39,420 --> 00:09:42,090 What else? 133 00:09:42,090 --> 00:09:43,670 Yes, Jimmy? 134 00:09:43,670 --> 00:09:46,460 AUDIENCE: Probably less here, but in agriculture, 135 00:09:46,460 --> 00:09:48,375 I'm pretty sure they're used in fertilizer. 136 00:09:48,375 --> 00:09:49,500 JOHN DOLHUN: Oh, gosh, yes. 137 00:09:49,500 --> 00:09:53,280 Fertilizers are a big thing because of lawns. 138 00:09:53,280 --> 00:10:00,920 So we've got soil here and fertilizers. 139 00:10:08,490 --> 00:10:11,670 Anything else? 140 00:10:11,670 --> 00:10:12,946 Jimmy? 141 00:10:12,946 --> 00:10:15,360 AUDIENCE: I guess animal droppings? 142 00:10:15,360 --> 00:10:16,530 JOHN DOLHUN: Absolutely. 143 00:10:16,530 --> 00:10:17,700 Animal waste. 144 00:10:17,700 --> 00:10:21,300 I mean, think about where do they put pig farms? 145 00:10:21,300 --> 00:10:24,940 They put them all by a river, right? 146 00:10:24,940 --> 00:10:30,720 And all those geese, the guano, droppings, everything, they're 147 00:10:30,720 --> 00:10:32,070 all out there by the river. 148 00:10:32,070 --> 00:10:35,190 And all that stuff is being washed in. 149 00:10:35,190 --> 00:10:38,520 So animal waste is a big, big source here. 150 00:10:46,790 --> 00:10:47,720 Anything else? 151 00:10:53,670 --> 00:10:57,270 You ever got your car washed in a car wash? 152 00:10:57,270 --> 00:10:59,610 Do you ever sit in it while you're going through, 153 00:10:59,610 --> 00:11:01,890 see all that soap coming down? 154 00:11:01,890 --> 00:11:03,330 Tons of soap. 155 00:11:03,330 --> 00:11:05,910 And all that soap's going into the sewer systems, 156 00:11:05,910 --> 00:11:12,300 and when it starts to rain, heavy rains, it bubbles over. 157 00:11:12,300 --> 00:11:14,700 So car washes would be a big source, 158 00:11:14,700 --> 00:11:17,130 and there's your polyphosphates. 159 00:11:23,130 --> 00:11:25,680 Another one that you might not be as familiar with 160 00:11:25,680 --> 00:11:26,565 is car exhausts. 161 00:11:35,460 --> 00:11:39,600 Car exhausts have a catalyst tube in there. 162 00:11:39,600 --> 00:11:44,800 When that tube gets hot, like 500, 600, 700 degrees, 163 00:11:44,800 --> 00:11:48,570 it can form cerium phosphate, which is released 164 00:11:48,570 --> 00:11:51,420 in the exhaust effluent. 165 00:11:51,420 --> 00:11:54,450 So cerium phosphate would be a culprit here. 166 00:11:58,560 --> 00:12:02,730 And then probably the biggest source 167 00:12:02,730 --> 00:12:07,050 is discharge from wastewater treatment plants. 168 00:12:07,050 --> 00:12:12,830 Did any of you ever go to tour a wastewater treatment plant? 169 00:12:12,830 --> 00:12:15,120 Anyone? 170 00:12:15,120 --> 00:12:17,370 Oh, you did? 171 00:12:17,370 --> 00:12:18,600 Kelly, right? 172 00:12:18,600 --> 00:12:20,340 Could you tell us-- tell us about it, 173 00:12:20,340 --> 00:12:22,410 what your experience was? 174 00:12:22,410 --> 00:12:24,900 AUDIENCE: It was a school fieldtrip a long time ago, 175 00:12:24,900 --> 00:12:26,730 I think. 176 00:12:26,730 --> 00:12:27,800 It was interesting. 177 00:12:27,800 --> 00:12:29,768 So they purified or treat the water 178 00:12:29,768 --> 00:12:31,244 with several different methods. 179 00:12:31,244 --> 00:12:33,400 On of them was just like, bacterial, 180 00:12:33,400 --> 00:12:35,644 and then they introduce it [INAUDIBLE].. 181 00:12:35,644 --> 00:12:37,770 JOHN DOLHUN: Yeah, they aerate it with bacteria, 182 00:12:37,770 --> 00:12:40,980 I think, in the secondary treatment. 183 00:12:40,980 --> 00:12:45,810 And they do that to get rid of organic matter 184 00:12:45,810 --> 00:12:48,270 or to digest it down to sludge. 185 00:12:48,270 --> 00:12:49,140 AUDIENCE: Yeah. 186 00:12:49,140 --> 00:12:51,692 And then there's a UV method. 187 00:12:51,692 --> 00:12:52,650 JOHN DOLHUN: Very good. 188 00:12:52,650 --> 00:12:55,920 I mean, the most modern plants have this ultraviolet rays 189 00:12:55,920 --> 00:12:57,270 at the very end. 190 00:12:57,270 --> 00:13:01,350 You can walk along and you can see a glass floor. 191 00:13:01,350 --> 00:13:03,450 You can see the water going through 192 00:13:03,450 --> 00:13:05,940 with the ultraviolet rays hitting it. 193 00:13:05,940 --> 00:13:09,870 And then, at the end, they have a faucet 194 00:13:09,870 --> 00:13:13,110 and they offer you a drink. 195 00:13:13,110 --> 00:13:15,780 I mean, there was no one in my group 196 00:13:15,780 --> 00:13:19,710 that availed themself to take a sip of that water 197 00:13:19,710 --> 00:13:22,080 after going through that. 198 00:13:22,080 --> 00:13:25,200 But let's put this in perspective. 199 00:13:25,200 --> 00:13:36,540 So wastewater treatment plants, they're 200 00:13:36,540 --> 00:13:40,020 all built along rivers or oceans. 201 00:13:40,020 --> 00:13:45,960 And when a heavy rain, they start to discharge. 202 00:13:45,960 --> 00:13:47,040 They have to discharge. 203 00:13:47,040 --> 00:13:48,750 They can't take the flow. 204 00:13:48,750 --> 00:13:50,880 First thing, they may discharge some 205 00:13:50,880 --> 00:13:53,280 of the secondary treated water. 206 00:13:53,280 --> 00:13:56,550 Sometimes, they have to discharge the raw sewage. 207 00:13:56,550 --> 00:13:59,850 But to put it in perspective, all of us 208 00:13:59,850 --> 00:14:08,640 produce about 2.2 grams of pee per day. 209 00:14:08,640 --> 00:14:11,970 I'm talking about phosphorus here. 210 00:14:11,970 --> 00:14:16,980 That's about 1.8 pounds per year. 211 00:14:19,720 --> 00:14:23,370 Now, when that phosphorus hits the sewage treatment plant, 212 00:14:23,370 --> 00:14:27,090 it's in the effluent, it gets diluted down. 213 00:14:27,090 --> 00:14:29,400 You're talking somewhere between 2 214 00:14:29,400 --> 00:14:40,410 and probably 20 milligrams per liter PPM of phosphorous 215 00:14:40,410 --> 00:14:42,720 in the water. 216 00:14:42,720 --> 00:14:46,050 After the secondary treatment, they only 217 00:14:46,050 --> 00:14:52,120 take out between 1 and 2 milligrams per liter. 218 00:14:52,120 --> 00:14:57,060 So you end up with a large excess of phosphorus 219 00:14:57,060 --> 00:14:59,770 in the treated water. 220 00:14:59,770 --> 00:15:03,720 So when they release, it's a ton of phosphorus 221 00:15:03,720 --> 00:15:05,550 hitting the water. 222 00:15:05,550 --> 00:15:07,890 But the good news is-- 223 00:15:07,890 --> 00:15:15,870 I'm going to draw a smiley face here, because the EPA just 224 00:15:15,870 --> 00:15:18,390 filed a regulation forcing-- 225 00:15:18,390 --> 00:15:21,180 they're going to force all these wastewater treatment 226 00:15:21,180 --> 00:15:26,197 plants to cut back, get rid of the phosphorus in the water, 227 00:15:26,197 --> 00:15:27,780 and they're going to have to-- they're 228 00:15:27,780 --> 00:15:30,330 going to have to take it down to less 229 00:15:30,330 --> 00:15:35,230 than 1.0 milligrams per liter. 230 00:15:35,230 --> 00:15:38,460 So all these plants are running around now trying to figure out 231 00:15:38,460 --> 00:15:39,960 how they're going to do that. 232 00:15:39,960 --> 00:15:42,990 This, I believe, just went into effect this year, 233 00:15:42,990 --> 00:15:47,490 and may go-- may be starting in January of 2020, 234 00:15:47,490 --> 00:15:52,290 but there are EPA regulations that are just coming out. 235 00:15:52,290 --> 00:15:55,590 The other major source is sewer overflows. 236 00:15:55,590 --> 00:15:59,040 And in New England, everyone-- 237 00:15:59,040 --> 00:16:03,730 it's notorious that you have a sump pump in your basement. 238 00:16:03,730 --> 00:16:07,710 So when your basement floods, the pump starts up 239 00:16:07,710 --> 00:16:08,880 and it pumps everything. 240 00:16:08,880 --> 00:16:11,080 They're connected to the sewer systems. 241 00:16:11,080 --> 00:16:12,960 So everything in the kitchen sink 242 00:16:12,960 --> 00:16:17,400 is going into the sewer system and it's bubbling over. 243 00:16:17,400 --> 00:16:20,260 So those are the primary sources. 244 00:16:20,260 --> 00:16:24,660 Now, let's look at the ecological effect 245 00:16:24,660 --> 00:16:27,420 of all this phosphorus. 246 00:16:27,420 --> 00:16:30,930 This is the Charles River, the famous Charles River. 247 00:16:30,930 --> 00:16:33,360 This is up by Newton, Mass. 248 00:16:33,360 --> 00:16:37,170 There's a guy in a canoe trying to pull out the vegetation 249 00:16:37,170 --> 00:16:39,600 out of the water. 250 00:16:39,600 --> 00:16:42,880 What this vegetation does is two things. 251 00:16:42,880 --> 00:16:46,920 First, it's blocking the sunlight 252 00:16:46,920 --> 00:16:51,540 to organisms and other plants down below the surface that 253 00:16:51,540 --> 00:16:52,920 need that sun. 254 00:16:52,920 --> 00:16:57,270 And the second thing is it's going to die and produce 255 00:16:57,270 --> 00:17:01,560 these swamp-like odors, and then it's 256 00:17:01,560 --> 00:17:04,800 going to get decomposed by microorganisms that 257 00:17:04,800 --> 00:17:07,599 are going to use up the oxygen. 258 00:17:07,599 --> 00:17:11,039 This is the result. This is blue-green algae. 259 00:17:14,440 --> 00:17:19,060 This is really-- another name for this is cyanobacteria. 260 00:17:19,060 --> 00:17:22,839 It's the cyanobacteria that give it that green color 261 00:17:22,839 --> 00:17:24,329 on the surface of the water. 262 00:17:27,050 --> 00:17:29,660 Here are some other forms of it. 263 00:17:29,660 --> 00:17:33,140 You can get this pea soup kind of look, 264 00:17:33,140 --> 00:17:35,900 or you can get this mossy look, or you 265 00:17:35,900 --> 00:17:38,240 might get a painted look. 266 00:17:38,240 --> 00:17:42,470 The bottom line is it's all bacteria. 267 00:17:42,470 --> 00:17:45,350 It's unicellular bacteria. 268 00:17:45,350 --> 00:17:47,600 These are prokaryotic bacteria. 269 00:17:47,600 --> 00:17:51,140 They have no nucleus, but they make their own food 270 00:17:51,140 --> 00:17:54,780 and they secrete chemicals. 271 00:17:54,780 --> 00:17:57,990 These are the same bacteria, believe it or not, 272 00:17:57,990 --> 00:18:02,530 that gave us life 3.5 billion years ago. 273 00:18:02,530 --> 00:18:04,500 And now, they're out to get us. 274 00:18:04,500 --> 00:18:06,990 Isn't that amazing? 275 00:18:06,990 --> 00:18:10,300 Every time I look at this, I can't believe it. 276 00:18:10,300 --> 00:18:12,120 I mean, when we had no oxygen, these 277 00:18:12,120 --> 00:18:14,850 were the guys that were giving our oxygen atmosphere, 278 00:18:14,850 --> 00:18:17,820 and now, look what they're doing. 279 00:18:17,820 --> 00:18:22,540 Now, if these are out there in the water, 280 00:18:22,540 --> 00:18:24,210 you don't want to go in the water. 281 00:18:24,210 --> 00:18:28,950 If you do, you are dead meat, and I'll tell you why. 282 00:18:28,950 --> 00:18:30,930 You can have all kinds of symptoms, 283 00:18:30,930 --> 00:18:33,900 you can get covered with a rash, you 284 00:18:33,900 --> 00:18:38,430 can have diarrhea, flu-like symptoms, eye and ear problems, 285 00:18:38,430 --> 00:18:41,070 respiratory problems. 286 00:18:41,070 --> 00:18:44,610 I gave you an article in the news. 287 00:18:44,610 --> 00:18:46,770 This is The New York Times. 288 00:18:46,770 --> 00:18:51,180 Central Park in New York, all of their ponds, 289 00:18:51,180 --> 00:18:53,730 infected with blue-green algae. 290 00:18:57,400 --> 00:18:58,940 Here's a good example. 291 00:18:58,940 --> 00:19:02,860 This is today, "Ohio strikes a Blow in Algae Fight." 292 00:19:02,860 --> 00:19:05,590 This is The Wall Street Journal this morning. 293 00:19:05,590 --> 00:19:08,020 This article just came out. 294 00:19:08,020 --> 00:19:12,680 Interestingly, Ohio had this algae problem 10 years ago, 295 00:19:12,680 --> 00:19:14,650 and they took around one of their lakes 296 00:19:14,650 --> 00:19:19,990 and they built up these wetland areas 297 00:19:19,990 --> 00:19:22,840 to prevent the runoff from reaching-- 298 00:19:22,840 --> 00:19:25,120 the agricultural runoff from reaching the lake, 299 00:19:25,120 --> 00:19:27,460 and it's actually working. 300 00:19:27,460 --> 00:19:30,490 So there are ideas out there that you 301 00:19:30,490 --> 00:19:32,605 can come up with an idea and solve a problem. 302 00:19:38,680 --> 00:19:41,850 So some of these cyanobacteria, some of the fresh water 303 00:19:41,850 --> 00:19:46,050 bacteria produce very toxic chemicals. 304 00:19:46,050 --> 00:19:50,070 One form of these are the microcystins. 305 00:19:50,070 --> 00:19:53,910 There are something like 50 different micocystins that 306 00:19:53,910 --> 00:19:56,220 have been identified to date. 307 00:19:56,220 --> 00:19:59,320 It's a cyclic peptide here. 308 00:19:59,320 --> 00:20:01,950 And this is a hepatotoxin. 309 00:20:01,950 --> 00:20:06,310 So once this gets through your skin into your body, 310 00:20:06,310 --> 00:20:09,660 your liver is going to get attacked, 311 00:20:09,660 --> 00:20:11,850 and you're pretty much gone. 312 00:20:11,850 --> 00:20:14,080 There's not much you can do about it. 313 00:20:14,080 --> 00:20:16,020 The article mentions the dogs-- 314 00:20:16,020 --> 00:20:19,480 one woman had three dogs in North Carolina. 315 00:20:19,480 --> 00:20:21,840 She let them go for a swim in a pond. 316 00:20:21,840 --> 00:20:25,860 All three dogs died within a few hours. 317 00:20:25,860 --> 00:20:28,670 So this is really nasty stuff. 318 00:20:28,670 --> 00:20:33,020 And I challenge you to think about coming up 319 00:20:33,020 --> 00:20:34,400 with an antidote for this. 320 00:20:36,960 --> 00:20:39,090 There's your startup company right here. 321 00:20:39,090 --> 00:20:40,290 I'm giving it to you. 322 00:20:43,890 --> 00:20:47,220 When this stuff is active, you go out to the Charles River, 323 00:20:47,220 --> 00:20:50,700 you'll see these signs posted warning people and pets 324 00:20:50,700 --> 00:20:52,460 to stay out of the water. 325 00:20:55,950 --> 00:20:57,310 Here's another example. 326 00:20:57,310 --> 00:21:00,720 This is the summer of 2014. 327 00:21:00,720 --> 00:21:04,440 This is a satellite picture of Lake Erie, one 328 00:21:04,440 --> 00:21:07,680 of the five Great Lakes in this country. 329 00:21:07,680 --> 00:21:13,170 And the lake actually borders Canada on one side, separates 330 00:21:13,170 --> 00:21:16,320 Canada from the US near Ontario, and then there 331 00:21:16,320 --> 00:21:20,250 are several states that border the lake. 332 00:21:20,250 --> 00:21:25,380 Out here to the west is Toledo, Ohio, and Toledo, 333 00:21:25,380 --> 00:21:28,260 fourth largest city in Ohio, has a population 334 00:21:28,260 --> 00:21:30,570 of about a half million. 335 00:21:30,570 --> 00:21:35,130 This was their tap water in 2014. 336 00:21:35,130 --> 00:21:40,590 And I had a 5.310 student in class four years ago who 337 00:21:40,590 --> 00:21:43,200 remembers this. 338 00:21:43,200 --> 00:21:46,380 I mean, this is serious business. 339 00:21:46,380 --> 00:21:48,580 And it's happening all over, all over the world. 340 00:21:51,230 --> 00:21:52,280 Here's another picture. 341 00:21:52,280 --> 00:21:58,710 This is the largest landlocked body of water on the Earth. 342 00:21:58,710 --> 00:22:01,290 Anybody from Europe here recognize this? 343 00:22:07,440 --> 00:22:07,940 What? 344 00:22:07,940 --> 00:22:09,350 Who said that? 345 00:22:09,350 --> 00:22:12,710 Yes, Sean, exactly correct, that's the Caspian Sea. 346 00:22:12,710 --> 00:22:14,750 It's bordered by five countries. 347 00:22:14,750 --> 00:22:19,670 But look at the massive, massive algal growth 348 00:22:19,670 --> 00:22:21,410 from this satellite picture. 349 00:22:21,410 --> 00:22:26,030 Here's the Volga River, Europe's longest river, pouring into it. 350 00:22:26,030 --> 00:22:29,250 It's a 2,000 mile long river. 351 00:22:29,250 --> 00:22:33,870 Here's a new word for you, eutrophication. 352 00:22:33,870 --> 00:22:37,220 It's from the Greek meaning well nourished. 353 00:22:40,580 --> 00:22:45,410 So how much phosphorus is acceptable? 354 00:22:45,410 --> 00:22:48,530 The EPA came out in 2000-- 355 00:22:48,530 --> 00:22:50,930 that was almost 20 years ago-- 356 00:22:50,930 --> 00:22:55,760 and said 0.0238 milligrams per liter. 357 00:22:55,760 --> 00:23:00,230 Well, we know today that if you have anything 358 00:23:00,230 --> 00:23:09,530 greater than or equal to 0.016 milligrams per liter, 359 00:23:09,530 --> 00:23:15,260 you're going to have really a large algal growth 360 00:23:15,260 --> 00:23:18,890 proliferating in your water. 361 00:23:18,890 --> 00:23:23,590 Now, these concentrations of phosphorus, they're low. 362 00:23:23,590 --> 00:23:26,890 And it's going to be challenging to measure those. 363 00:23:26,890 --> 00:23:29,150 This is what we're going to do. 364 00:23:29,150 --> 00:23:31,390 The other thing that makes it challenging 365 00:23:31,390 --> 00:23:38,690 is phosphates are colorless. 366 00:23:38,690 --> 00:23:41,630 So how are we going to use UV vis to measure 367 00:23:41,630 --> 00:23:43,040 these concentrations? 368 00:23:46,700 --> 00:23:47,890 Anybody have an idea? 369 00:23:57,310 --> 00:23:58,480 Yes? 370 00:23:58,480 --> 00:24:01,240 Maybe we can react them with something 371 00:24:01,240 --> 00:24:03,090 that will make them colorful? 372 00:24:03,090 --> 00:24:05,340 Maybe we can react them with something 373 00:24:05,340 --> 00:24:06,570 that can make them colorful. 374 00:24:06,570 --> 00:24:08,040 Very good. 375 00:24:08,040 --> 00:24:09,000 Very good. 376 00:24:09,000 --> 00:24:11,220 Yeah, I like that. 377 00:24:11,220 --> 00:24:12,650 Keisha, right? 378 00:24:12,650 --> 00:24:14,865 AUDIENCE: Gizelle. 379 00:24:14,865 --> 00:24:15,740 JOHN DOLHUN: Gizelle. 380 00:24:15,740 --> 00:24:17,270 I'm sorry, Gizelle. 381 00:24:17,270 --> 00:24:18,810 Where's Keisha? 382 00:24:18,810 --> 00:24:19,670 There she is. 383 00:24:19,670 --> 00:24:20,960 OK. 384 00:24:20,960 --> 00:24:23,540 All right, so react them with something 385 00:24:23,540 --> 00:24:26,180 that makes it colorful. 386 00:24:26,180 --> 00:24:30,410 So here comes chemistry to the rescue, right? 387 00:24:30,410 --> 00:24:34,280 So phosphates are very reactive. 388 00:24:34,280 --> 00:24:39,560 So we can actually take river water and this method here, 389 00:24:39,560 --> 00:24:42,590 this is the ammonium metavanadate method. 390 00:24:42,590 --> 00:24:48,320 When I tried to develop this Charles River water testing, 391 00:24:48,320 --> 00:24:50,660 I started with this method because it 392 00:24:50,660 --> 00:24:54,440 was written up as the method to detect phosphorus 393 00:24:54,440 --> 00:24:56,000 in river water. 394 00:24:56,000 --> 00:24:57,860 So you would take the river water, 395 00:24:57,860 --> 00:25:01,850 mix it with molybdate, ammonium metavanadate, 396 00:25:01,850 --> 00:25:07,340 and you create this color heteropoly molybdic acid 397 00:25:07,340 --> 00:25:10,250 that has a yellow color and it absorbs light 398 00:25:10,250 --> 00:25:14,240 at 400 nanometers. 399 00:25:14,240 --> 00:25:19,160 What I found is that this method was not sensitive enough 400 00:25:19,160 --> 00:25:21,980 to actually measure the phosphorus 401 00:25:21,980 --> 00:25:25,130 levels in the Charles River. 402 00:25:25,130 --> 00:25:28,700 It's a great method for measuring phosphorus in sewage, 403 00:25:28,700 --> 00:25:30,560 but not the rivers. 404 00:25:30,560 --> 00:25:32,690 So I looked around and I found what's 405 00:25:32,690 --> 00:25:38,120 called the ascorbic acid method, an EPA-approved method where 406 00:25:38,120 --> 00:25:43,340 you actually took river water, mixed it 407 00:25:43,340 --> 00:25:47,210 with molybdate, sulfuric acid, and you 408 00:25:47,210 --> 00:25:53,090 create this heteropoly molybdic acid, which is colorless. 409 00:25:53,090 --> 00:25:59,090 But the good thing is this heteropoly molybdate anion 410 00:25:59,090 --> 00:26:03,260 can accept electrons and be reduced down 411 00:26:03,260 --> 00:26:07,620 and ascorbic acid can cause that reduction. 412 00:26:07,620 --> 00:26:11,600 And you end up getting this molybdenum blue complex, 413 00:26:11,600 --> 00:26:14,810 a mixed valence complex that absorbs light 414 00:26:14,810 --> 00:26:19,630 at 880 nanometers. 415 00:26:19,630 --> 00:26:22,450 So this is great because the concentration 416 00:26:22,450 --> 00:26:25,450 of the phosphorus in the complexes 417 00:26:25,450 --> 00:26:27,340 is proportional to the absorbance 418 00:26:27,340 --> 00:26:30,620 of the light in these things. 419 00:26:30,620 --> 00:26:34,060 So this is what you're actually making. 420 00:26:34,060 --> 00:26:35,020 It's beautiful. 421 00:26:35,020 --> 00:26:36,970 This is a Keggin structure. 422 00:26:36,970 --> 00:26:41,770 It captures the phosphorus in the center, surrounded by 12 423 00:26:41,770 --> 00:26:45,790 molybdenums and 40 oxygens. 424 00:26:45,790 --> 00:26:49,360 I want you to take a moment and look at this. 425 00:26:49,360 --> 00:26:52,120 And I'd like you all to close your eyes for a moment 426 00:26:52,120 --> 00:26:54,490 and think about this image. 427 00:26:54,490 --> 00:26:55,390 Close your eyes. 428 00:27:02,260 --> 00:27:05,770 OK, open your eyes, please. 429 00:27:05,770 --> 00:27:09,010 I want you to carry this image with you 430 00:27:09,010 --> 00:27:13,690 into the lab when you do this experiment. 431 00:27:13,690 --> 00:27:17,280 You're actually going to be making this in your beakers 432 00:27:17,280 --> 00:27:21,330 when you add the color developer to your water samples. 433 00:27:21,330 --> 00:27:26,310 You're creating this in about 15 minutes in your beaker. 434 00:27:26,310 --> 00:27:28,695 This is inorganic chemistry at its best. 435 00:27:31,490 --> 00:27:36,410 Now, I want to spend the next several slides showing you 436 00:27:36,410 --> 00:27:39,080 how we're going to actually measure 437 00:27:39,080 --> 00:27:43,080 the concentrations of this. 438 00:27:43,080 --> 00:27:47,240 So we're going to be shining electromagnetic energy 439 00:27:47,240 --> 00:27:49,710 on a sample. 440 00:27:49,710 --> 00:27:52,640 And if you look at the visible light 441 00:27:52,640 --> 00:27:57,020 here that I broke out of this electromagnetic spectrum, 442 00:27:57,020 --> 00:28:01,100 on the red end of this, we're going 443 00:28:01,100 --> 00:28:04,760 to be looking at our samples on that far red end 444 00:28:04,760 --> 00:28:07,010 in the near IR. 445 00:28:07,010 --> 00:28:08,720 So that's where you're going to be-- 446 00:28:08,720 --> 00:28:10,670 where you're going to be taking your readings. 447 00:28:10,670 --> 00:28:15,585 Now, what can happen when you shine radiation on your sample? 448 00:28:15,585 --> 00:28:16,085 Anyone? 449 00:28:19,590 --> 00:28:20,655 Yes, Kim. 450 00:28:20,655 --> 00:28:24,904 AUDIENCE: Photobleaching 451 00:28:24,904 --> 00:28:25,696 JOHN DOLHUN: Sorry? 452 00:28:25,696 --> 00:28:28,080 AUDIENCE: Some of your sample could get photobleached. 453 00:28:28,080 --> 00:28:30,840 JOHN DOLHUN: Some of your sample could get photobleached, yeah. 454 00:28:30,840 --> 00:28:33,020 That's a possibility. 455 00:28:33,020 --> 00:28:35,910 What else? 456 00:28:35,910 --> 00:28:36,410 Yes? 457 00:28:36,410 --> 00:28:39,679 AUDIENCE: [INAUDIBLE] 458 00:28:43,420 --> 00:28:44,480 JOHN DOLHUN: Exactly. 459 00:28:44,480 --> 00:28:46,600 I mean, electrons could get chewed up 460 00:28:46,600 --> 00:28:48,490 to a higher energy levels. 461 00:28:48,490 --> 00:28:51,190 Little nuclei could see that happen and get nervous 462 00:28:51,190 --> 00:28:53,320 and start to rearrange themselves. 463 00:28:53,320 --> 00:28:56,980 And the molecule, as Kelly said, could burst into vibration. 464 00:28:56,980 --> 00:29:06,030 And your UV is actually monitoring 465 00:29:06,030 --> 00:29:08,850 all of those electronic transmissions 466 00:29:08,850 --> 00:29:12,570 that we can't see with our eye. 467 00:29:12,570 --> 00:29:17,980 And what the UV does is it draws you a smooth curve through all 468 00:29:17,980 --> 00:29:21,400 of those electronic transitions and you end up somewhere 469 00:29:21,400 --> 00:29:24,550 with your lambda max. 470 00:29:24,550 --> 00:29:28,390 What UV vis is, a good definition 471 00:29:28,390 --> 00:29:31,810 is it's just the interaction of light with matter 472 00:29:31,810 --> 00:29:33,991 as a function of wavelength. 473 00:29:37,760 --> 00:29:39,820 So here's your UV cuvette. 474 00:29:39,820 --> 00:29:43,040 Here's the radiation hitting that cuvette. 475 00:29:43,040 --> 00:29:45,640 What happens? 476 00:29:45,640 --> 00:29:47,583 What do you see up there happening? 477 00:29:53,270 --> 00:29:54,070 Yes, Ryan? 478 00:29:58,855 --> 00:30:00,070 Yeah, the lights focused. 479 00:30:00,070 --> 00:30:01,945 And what's happening to the sample? 480 00:30:11,080 --> 00:30:13,300 I'm sure it's heating up, yeah. 481 00:30:13,300 --> 00:30:14,570 Yes, Autumn? 482 00:30:14,570 --> 00:30:17,300 AUDIENCE: It absorbs sunlight and transmits sunlight and also 483 00:30:17,300 --> 00:30:17,800 re-emits. 484 00:30:20,190 --> 00:30:21,190 JOHN DOLHUN: Yeah, good. 485 00:30:21,190 --> 00:30:22,920 So some of the light's going through 486 00:30:22,920 --> 00:30:24,930 and some's getting absorbed. 487 00:30:24,930 --> 00:30:27,790 So let's look at that for a minute. 488 00:30:27,790 --> 00:30:31,920 So we've got absorbance minus the log 489 00:30:31,920 --> 00:30:36,180 of the transmitted light, which is i over i0. 490 00:30:38,895 --> 00:30:45,660 Now, absorbance is-- we're actually 491 00:30:45,660 --> 00:30:47,070 monitoring the absorbance. 492 00:30:47,070 --> 00:30:49,440 We're not monitoring the transmittance 493 00:30:49,440 --> 00:30:51,840 because absorbance is actually directly 494 00:30:51,840 --> 00:30:57,220 proportional to concentration by Beer's law. 495 00:30:57,220 --> 00:31:00,600 So we have this relationship. 496 00:31:00,600 --> 00:31:04,260 And E, the extinction coefficient, 497 00:31:04,260 --> 00:31:07,440 is the molar absorptivity constant, 498 00:31:07,440 --> 00:31:12,840 is simply the amount of light absorbed per unit 499 00:31:12,840 --> 00:31:17,140 concentration of your sample. 500 00:31:17,140 --> 00:31:18,840 Let me just rewrite this. 501 00:31:18,840 --> 00:31:20,500 Let me get rid of the logarithm. 502 00:31:20,500 --> 00:31:22,060 I want to show you something here. 503 00:31:22,060 --> 00:31:26,040 So I'm going to rewrite this. 504 00:31:35,140 --> 00:31:41,470 Let's actually graph the intensity 505 00:31:41,470 --> 00:31:45,180 of the incoming radiation here. 506 00:31:45,180 --> 00:31:56,090 We're going to graph that as a function of concentration. 507 00:31:56,090 --> 00:32:02,740 If you do that, you're going to see from that equation 508 00:32:02,740 --> 00:32:06,820 that the transmitted light decreases exponentially 509 00:32:06,820 --> 00:32:09,940 as the concentration increases. 510 00:32:09,940 --> 00:32:14,110 I want you to keep that in the back of your mind. 511 00:32:14,110 --> 00:32:16,450 This equation fascinated me. 512 00:32:16,450 --> 00:32:19,480 I like Beer's law. 513 00:32:19,480 --> 00:32:22,030 What this tells you, this extinction coefficient 514 00:32:22,030 --> 00:32:25,610 tells you, that it has to be a constant. 515 00:32:25,610 --> 00:32:27,970 So if you cut your concentration in half, 516 00:32:27,970 --> 00:32:30,710 absorption should be cut in half. 517 00:32:30,710 --> 00:32:32,390 So I wanted to prove this. 518 00:32:32,390 --> 00:32:35,590 So I went out and I made this compound, 519 00:32:35,590 --> 00:32:38,230 hexacyanoferrate(III). 520 00:32:38,230 --> 00:32:41,830 And I made up five solutions of this, 521 00:32:41,830 --> 00:32:45,440 and then I measured the absorbance of each solution. 522 00:32:45,440 --> 00:32:49,120 It absorbed light at 420 nanometers. 523 00:32:49,120 --> 00:32:53,505 And if you look here, 10 times e to the minus 4, 524 00:32:53,505 --> 00:32:58,600 if I cut that in half to 5 times e to the minus 4, indeed, 525 00:32:58,600 --> 00:33:02,900 the absorption gets cut in half as it should. 526 00:33:02,900 --> 00:33:07,690 So I graph this, got a nice, straight line. 527 00:33:07,690 --> 00:33:10,840 The change in absorption over the change in concentration 528 00:33:10,840 --> 00:33:11,980 is my slope. 529 00:33:11,980 --> 00:33:17,770 And it's 1,056.7 so that's my extinction coefficient. 530 00:33:17,770 --> 00:33:21,610 And this worked really well. 531 00:33:21,610 --> 00:33:24,670 But I want to caution you-- 532 00:33:24,670 --> 00:33:30,640 if you try this, and you're graphing absorption 533 00:33:30,640 --> 00:33:34,510 versus concentration, and you're doing Beer's law, 534 00:33:34,510 --> 00:33:36,820 you've got this nice, straight line, 535 00:33:36,820 --> 00:33:40,180 you might end up with something like this, 536 00:33:40,180 --> 00:33:43,600 where Beer's law falls apart. 537 00:33:43,600 --> 00:33:47,690 And it all comes back to this here-- 538 00:33:47,690 --> 00:33:49,790 the intensity of the transmitted light 539 00:33:49,790 --> 00:33:53,190 decreases exponentially with concentration. 540 00:33:53,190 --> 00:33:56,930 So eventually, if the concentration is too high 541 00:33:56,930 --> 00:34:01,400 your sample becomes saturated, and you're not 542 00:34:01,400 --> 00:34:04,310 going to be-- this Beer's law falls apart. 543 00:34:04,310 --> 00:34:06,530 I just want you to be aware of that. 544 00:34:06,530 --> 00:34:10,310 What I did is I made up all of my concentrations are very low. 545 00:34:10,310 --> 00:34:13,920 Beer's law worked fine. 546 00:34:13,920 --> 00:34:21,350 So now we're going to get to some serious business. 547 00:34:21,350 --> 00:34:25,230 This is what you have to do for this lab, for it to work. 548 00:34:25,230 --> 00:34:27,110 Otherwise, you will be a goner-- 549 00:34:27,110 --> 00:34:28,489 gonzo. 550 00:34:28,489 --> 00:34:31,719 You've got to clean this glassware. 551 00:34:31,719 --> 00:34:34,880 This is a list of the glassware that you'll need to clean. 552 00:34:34,880 --> 00:34:38,630 And you've got to do it with 10% hydrochloric acid, triple 553 00:34:38,630 --> 00:34:41,199 rinsed with Milli-Q Water. 554 00:34:41,199 --> 00:34:43,150 Why do you think you need to do that? 555 00:34:47,860 --> 00:34:48,949 Yes. 556 00:34:48,949 --> 00:34:51,580 AUDIENCE: Any contamination might change the products 557 00:34:51,580 --> 00:34:55,150 concentration. 558 00:34:55,150 --> 00:34:56,860 JOHN DOLHUN: Any contamination is going 559 00:34:56,860 --> 00:34:59,590 to just destroy the experiment. 560 00:34:59,590 --> 00:35:01,740 It's kind of like the Nano Building. 561 00:35:01,740 --> 00:35:05,260 You've seen them in there with their bunny suits on. 562 00:35:05,260 --> 00:35:10,060 One speck of dust, even a dander from your hair, 563 00:35:10,060 --> 00:35:13,510 is like a wrecking ball to the experiment. 564 00:35:13,510 --> 00:35:18,760 Well, one speck of phosphate from any detergent 565 00:35:18,760 --> 00:35:21,920 is going to wreck this experiment. 566 00:35:21,920 --> 00:35:24,340 So you've got to judiciously sit down. 567 00:35:24,340 --> 00:35:27,500 There'll be two of you-- you'll be partnered up for this. 568 00:35:27,500 --> 00:35:29,650 So you clean this up. 569 00:35:29,650 --> 00:35:33,310 And you'll do this on day two after the dissolved oxygen 570 00:35:33,310 --> 00:35:34,455 testing. 571 00:35:34,455 --> 00:35:35,830 This is what you're going to need 572 00:35:35,830 --> 00:35:38,860 for day three for the phosphate testing. 573 00:35:38,860 --> 00:35:42,070 So you can leave this glassware in the top drawer 574 00:35:42,070 --> 00:35:43,570 above your locker. 575 00:35:43,570 --> 00:35:45,070 It's not locked. 576 00:35:45,070 --> 00:35:47,020 And it'll be nice and ready for when 577 00:35:47,020 --> 00:35:50,570 you come in to do the testing. 578 00:35:50,570 --> 00:35:55,490 So this is what you have to do in this lab. 579 00:35:55,490 --> 00:35:58,780 First of all, we need to make up a set of standards 580 00:35:58,780 --> 00:36:00,670 that we can interpolate our river 581 00:36:00,670 --> 00:36:04,960 samples against to find the concentrations of the phosphate 582 00:36:04,960 --> 00:36:06,260 and phosphorus. 583 00:36:06,260 --> 00:36:08,710 So you're going to make seven standards up. 584 00:36:08,710 --> 00:36:13,240 And you're going to be using a stock solution. 585 00:36:16,580 --> 00:36:19,820 And the formula to use in all these tables 586 00:36:19,820 --> 00:36:23,900 is you're going to use this M1V1 equals M2V2. 587 00:36:27,810 --> 00:36:37,260 So if you have a 10 to the minus 1/3 molar stock solution, 588 00:36:37,260 --> 00:36:45,810 and you're taking 1 milliliter of it out, out of the bottle, 589 00:36:45,810 --> 00:36:48,255 how much molarity do you want to make 590 00:36:48,255 --> 00:36:53,850 to make up 100 mil solution? 591 00:36:53,850 --> 00:36:56,130 You'll be diluting this 1 mil to 100, 592 00:36:56,130 --> 00:36:59,400 and you'll see that your x is 10 to the minus 5. 593 00:36:59,400 --> 00:37:01,470 That's your stock solution of phosphate 594 00:37:01,470 --> 00:37:03,140 that you're going to create. 595 00:37:06,540 --> 00:37:09,300 So you just use that formula for all these. 596 00:37:09,300 --> 00:37:11,640 You're taking this much out of your 10 597 00:37:11,640 --> 00:37:14,220 to the minus 5 molar stock solution, 598 00:37:14,220 --> 00:37:16,800 and you're diluting it up to 10 mils. 599 00:37:16,800 --> 00:37:19,230 What's my concentration? 600 00:37:19,230 --> 00:37:20,730 Perfect. 601 00:37:20,730 --> 00:37:22,590 What you'll do is you'll come into the lab, 602 00:37:22,590 --> 00:37:25,170 and the TAs will go through this with you. 603 00:37:25,170 --> 00:37:27,990 You'll make up your stock solutions. 604 00:37:27,990 --> 00:37:31,410 And then you'll go to the river to get your water. 605 00:37:31,410 --> 00:37:36,690 And when you bring the water back to the lab, 606 00:37:36,690 --> 00:37:38,260 there'll be two of you. 607 00:37:38,260 --> 00:37:41,070 So one of you will go over to the hoods 608 00:37:41,070 --> 00:37:43,320 and get the color developer. 609 00:37:43,320 --> 00:37:47,190 And these are the four chemicals that we talked about 610 00:37:47,190 --> 00:37:48,930 in the color developer-- 611 00:37:48,930 --> 00:37:54,150 the ammonium molybdate, sulfuric acid, ascorbic acid, 612 00:37:54,150 --> 00:37:56,910 potassium antimonyl-tartrate. 613 00:37:56,910 --> 00:38:01,080 Potassium antimonyl-tartrate is there to actually speed up 614 00:38:01,080 --> 00:38:05,190 the reduction that's going on with ascorbic acid. 615 00:38:05,190 --> 00:38:07,110 That's important. 616 00:38:07,110 --> 00:38:11,460 If I didn't mention that before, that's the purpose of that. 617 00:38:11,460 --> 00:38:13,830 The ammonium molybdate, sulfuric acid, 618 00:38:13,830 --> 00:38:16,380 you're creating that Keggin structure, 619 00:38:16,380 --> 00:38:20,460 that heteropoly, colorless, molybdic acid. 620 00:38:20,460 --> 00:38:23,520 You also have to take this color developer in the order 621 00:38:23,520 --> 00:38:25,050 that it's written here. 622 00:38:25,050 --> 00:38:28,230 It'll be set up in burettes in the hood. 623 00:38:28,230 --> 00:38:31,620 If you, for example, take it in a wrong order, 624 00:38:31,620 --> 00:38:34,170 you could have a side reaction, and not 625 00:38:34,170 --> 00:38:39,280 get the color developer that you want to put in your sample. 626 00:38:39,280 --> 00:38:40,540 So it's important. 627 00:38:40,540 --> 00:38:43,860 So one of you will go to the hood, get the color developer. 628 00:38:43,860 --> 00:38:47,910 The other one will go to the river water you brought back, 629 00:38:47,910 --> 00:38:51,210 use a clean pipette, 10 mL pipette, 630 00:38:51,210 --> 00:38:55,095 and pipette five beakers with river water, five 631 00:38:55,095 --> 00:38:56,790 10-mL beakers. 632 00:38:56,790 --> 00:39:02,790 So you'll end up with 12-- seven standards and five samples. 633 00:39:02,790 --> 00:39:04,920 And then you add the color developer, 634 00:39:04,920 --> 00:39:10,240 and you wait 20 minutes, and you're ready to go. 635 00:39:10,240 --> 00:39:15,450 Just a couple other precautions that you should take-- 636 00:39:15,450 --> 00:39:18,020 we're going to be using 4-mL cuvettes. 637 00:39:18,020 --> 00:39:19,290 These are big inside. 638 00:39:19,290 --> 00:39:22,410 Don't use the 1 and 1/2 mL cuvettes. 639 00:39:22,410 --> 00:39:26,940 The other thing is all these cuvettes have a fill line. 640 00:39:26,940 --> 00:39:30,000 It becomes frosted at one point. 641 00:39:30,000 --> 00:39:33,900 And you want to stop pouring when you get to that line. 642 00:39:33,900 --> 00:39:35,490 You're going to take your beakers, 643 00:39:35,490 --> 00:39:37,620 and you're going to swirl them gently. 644 00:39:37,620 --> 00:39:39,720 And you're going to pour them by hand 645 00:39:39,720 --> 00:39:41,760 until you reach the fill line. 646 00:39:41,760 --> 00:39:43,410 Don't go beyond that. 647 00:39:43,410 --> 00:39:48,090 Also, all of these UV cuvettes have an arrow on one side. 648 00:39:48,090 --> 00:39:50,220 You want to be sure that the arrow is 649 00:39:50,220 --> 00:39:53,580 in the light beam when you put these cuvettes in the UV 650 00:39:53,580 --> 00:39:54,960 spectrometer. 651 00:39:54,960 --> 00:39:56,960 A lot of people have made mistakes, 652 00:39:56,960 --> 00:39:58,710 put them in the wrong way, and then you're 653 00:39:58,710 --> 00:40:01,080 not going to get very good readings. 654 00:40:01,080 --> 00:40:02,880 So the arrow's clear to see. 655 00:40:02,880 --> 00:40:05,790 What I usually do is arrange all my cuvettes 656 00:40:05,790 --> 00:40:07,770 in a box ahead of time. 657 00:40:07,770 --> 00:40:10,590 And then I pour my samples and put them in the box, 658 00:40:10,590 --> 00:40:12,970 and I know the arrow's in the right place. 659 00:40:12,970 --> 00:40:15,780 And when I go to the UV, I just lift them up and put them in. 660 00:40:18,300 --> 00:40:23,160 Also, keep in mind what Dr. Sarah Hewett told you 661 00:40:23,160 --> 00:40:27,120 the other day that there's two kinds of pipettes in the lab. 662 00:40:27,120 --> 00:40:29,910 This one is a blowout pipette. 663 00:40:29,910 --> 00:40:33,480 You've got to blow it all out to get your 10 mLs. 664 00:40:33,480 --> 00:40:36,660 This one is a to deliver pipette. 665 00:40:36,660 --> 00:40:38,430 You only go up to that last line. 666 00:40:38,430 --> 00:40:42,750 You don't blow the tip in, otherwise you put too much-- 667 00:40:42,750 --> 00:40:44,560 going to wreck your experiment. 668 00:40:44,560 --> 00:40:46,860 So make sure you look at the pipettes carefully. 669 00:40:49,880 --> 00:40:53,910 So you're going to get your graph here, a nice graph. 670 00:40:53,910 --> 00:40:55,610 And what you're going to do is you're 671 00:40:55,610 --> 00:40:58,250 going to interpolate now your river 672 00:40:58,250 --> 00:41:01,760 absorbances against the curve so you can read off 673 00:41:01,760 --> 00:41:03,050 the concentrations. 674 00:41:12,820 --> 00:41:19,330 So the concentrations in that graph are in micromolar. 675 00:41:19,330 --> 00:41:21,760 So you're going to want to take those and convert 676 00:41:21,760 --> 00:41:24,440 them to milligrams per liter. 677 00:41:24,440 --> 00:41:26,230 So you want to convert this first 678 00:41:26,230 --> 00:41:31,780 to a molarity, moles per liter. 679 00:41:34,930 --> 00:41:44,740 Then you take that, and you want to go down to grams per liter, 680 00:41:44,740 --> 00:41:47,440 and then finally milligrams per liter. 681 00:41:52,110 --> 00:41:54,550 So you're going to be calculating two things. 682 00:41:54,550 --> 00:42:02,110 You want to calculate the phosphate concentration in ppm, 683 00:42:02,110 --> 00:42:04,510 which is milligrams per liter, and the phosphorus 684 00:42:04,510 --> 00:42:06,050 concentration. 685 00:42:06,050 --> 00:42:10,630 So you'll take your mass from the curve in milligrams 686 00:42:10,630 --> 00:42:16,090 per liter, and take it times the ratio for phosphate of PO4 687 00:42:16,090 --> 00:42:18,040 over KH2PO4. 688 00:42:18,040 --> 00:42:20,770 And that ratio is 0.70. 689 00:42:20,770 --> 00:42:23,680 And then for phosphorus, do the same thing. 690 00:42:23,680 --> 00:42:26,410 The ratio there is 0.23. 691 00:42:26,410 --> 00:42:29,380 And this is the most important part of this lab-- 692 00:42:29,380 --> 00:42:32,290 this is the whole thing, calculating 693 00:42:32,290 --> 00:42:35,140 these concentrations in the end. 694 00:42:35,140 --> 00:42:39,650 So it's important to know how to do that. 695 00:42:39,650 --> 00:42:42,070 So once you get your concentrations, 696 00:42:42,070 --> 00:42:45,550 you've got a series of things to go through here 697 00:42:45,550 --> 00:42:48,190 for your data analysis. 698 00:42:48,190 --> 00:42:52,210 There's no error propagation on this part of the lab, which 699 00:42:52,210 --> 00:42:54,680 is good for you. 700 00:42:54,680 --> 00:42:57,370 You will have to use the LINEST equation 701 00:42:57,370 --> 00:43:01,570 that Sarah talked about, which is pretty easy to use. 702 00:43:01,570 --> 00:43:04,750 And that'll help you calculate the errors of your slope 703 00:43:04,750 --> 00:43:07,070 intercept and y values. 704 00:43:07,070 --> 00:43:10,120 And then you find your average and standard deviation 705 00:43:10,120 --> 00:43:14,080 of the five measurements, calculate the 95% confidence 706 00:43:14,080 --> 00:43:15,520 interval. 707 00:43:15,520 --> 00:43:18,460 Most importantly, report the final concentration 708 00:43:18,460 --> 00:43:20,980 of P and PO4. 709 00:43:20,980 --> 00:43:26,260 Make sure all these results show up in your abstract. 710 00:43:26,260 --> 00:43:28,570 First thing I do when I get lab reports is I 711 00:43:28,570 --> 00:43:29,920 look at the abstract. 712 00:43:29,920 --> 00:43:35,890 I want to see a line that shows my results. 713 00:43:35,890 --> 00:43:39,670 And they also should appear in your conclusion, 714 00:43:39,670 --> 00:43:43,970 and then you can discuss them in your discussion of your lab 715 00:43:43,970 --> 00:43:44,470 report. 716 00:43:47,700 --> 00:43:51,390 So any questions about this? 717 00:43:51,390 --> 00:43:55,320 I know you're going to have a busy weekend because you're 718 00:43:55,320 --> 00:43:58,980 going to be working on your ferrocene lab, your first lab 719 00:43:58,980 --> 00:44:00,360 report. 720 00:44:00,360 --> 00:44:02,340 And I want to tell you that please, 721 00:44:02,340 --> 00:44:05,370 feel free to reach out to me or Sarah 722 00:44:05,370 --> 00:44:07,680 if you have any questions. 723 00:44:07,680 --> 00:44:09,930 I'm going to be here tomorrow. 724 00:44:09,930 --> 00:44:13,620 I probably will be here Saturday and Sunday. 725 00:44:13,620 --> 00:44:16,290 So if there's a last minute question, 726 00:44:16,290 --> 00:44:20,910 just send me an email, and I'm happy to invite you in, 727 00:44:20,910 --> 00:44:24,240 and we can answer your question. 728 00:44:24,240 --> 00:44:26,400 I should be here in the afternoon, probably, 729 00:44:26,400 --> 00:44:29,190 on Saturday and Sunday. 730 00:44:29,190 --> 00:44:39,510 Now, I'd like to end the lecture today by doing a demonstration. 731 00:44:39,510 --> 00:44:41,080 Actually, did I turn that off? 732 00:44:41,080 --> 00:44:42,930 I can show you this here. 733 00:44:42,930 --> 00:44:47,100 I'm going to do this Briggs-Rauscher reaction. 734 00:44:47,100 --> 00:44:54,300 Actually, we're going to make this iodomalonic acid. 735 00:44:54,300 --> 00:44:57,480 We're going to actually attach an iodine to malonic acid. 736 00:44:57,480 --> 00:45:00,120 We're going to create this in a beaker. 737 00:45:00,120 --> 00:45:01,980 The reason I'm showing you this reaction 738 00:45:01,980 --> 00:45:06,720 is because it has everything in it, including starch. 739 00:45:06,720 --> 00:45:09,000 And it has a lot of colors. 740 00:45:09,000 --> 00:45:12,000 And these colors are things that we're 741 00:45:12,000 --> 00:45:16,140 going to talk about in the next lecture, what starch does 742 00:45:16,140 --> 00:45:17,290 and how it works. 743 00:45:17,290 --> 00:45:21,540 And this is kind of a preview to that. 744 00:45:21,540 --> 00:45:23,160 This reaction that you're going to see 745 00:45:23,160 --> 00:45:28,410 was actually discovered by two high school chemistry teachers. 746 00:45:28,410 --> 00:45:31,860 They're Briggs and Rauscher from Galileo High School, 747 00:45:31,860 --> 00:45:34,680 my favorite city, San Francisco. 748 00:45:34,680 --> 00:45:39,370 So these guys came up with this back in, I think, 1973. 749 00:45:39,370 --> 00:45:43,290 They published a paper in the Journal of Chemical Education. 750 00:45:43,290 --> 00:45:48,690 And they had every scientist in the country puzzled. 751 00:45:48,690 --> 00:45:50,940 And it took about 10 years to work out 752 00:45:50,940 --> 00:45:53,130 all the and sundry reactions that 753 00:45:53,130 --> 00:45:56,140 are going on in this reaction. 754 00:45:56,140 --> 00:46:00,300 So I'm going to put on some safety glasses. 755 00:46:00,300 --> 00:46:07,400 And what I'm going to be doing is 756 00:46:07,400 --> 00:46:12,270 going to be mixing three colorless solutions in here. 757 00:46:12,270 --> 00:46:14,280 This is my first one. 758 00:46:14,280 --> 00:46:17,580 And I'm going to use kitchen chemistry, which 759 00:46:17,580 --> 00:46:20,668 means I'm kind of looking at that scale over there 760 00:46:20,668 --> 00:46:21,960 and I'm going to pour these in. 761 00:46:32,080 --> 00:46:35,820 So let's put a little more. 762 00:46:35,820 --> 00:46:38,050 That's colorless, right? 763 00:46:38,050 --> 00:46:40,485 OK, next colorless solution. 764 00:46:55,610 --> 00:46:58,780 That's about right. 765 00:46:58,780 --> 00:47:02,120 And the final colorless solution-- keep your eye on it. 766 00:47:10,480 --> 00:47:14,530 Oh my goodness, wow. 767 00:47:14,530 --> 00:47:15,940 It wasn't supposed to do that. 768 00:47:22,380 --> 00:47:24,690 What? 769 00:47:24,690 --> 00:47:25,590 Are you kidding me? 770 00:47:32,400 --> 00:47:33,440 What's going on here? 771 00:47:37,010 --> 00:47:38,450 Get your clock out. 772 00:47:38,450 --> 00:47:40,120 This is a clock reaction. 773 00:47:40,120 --> 00:47:41,630 You can keep time with this. 774 00:47:53,600 --> 00:47:56,770 So I'll give you a little hint. 775 00:47:56,770 --> 00:48:00,940 There iodide in there, I minus. 776 00:48:04,060 --> 00:48:06,550 And I minus is colorless. 777 00:48:11,560 --> 00:48:15,580 There is iodine in there, and iodine is amber. 778 00:48:22,030 --> 00:48:27,520 When they're both present, it's blue-black. 779 00:48:27,520 --> 00:48:30,610 And we're going to see why that is in the next lecture. 780 00:48:36,650 --> 00:48:40,180 So there's a lot of reactions going on in there. 781 00:48:40,180 --> 00:48:45,640 When these reactants react, they form hypoiodous acid. 782 00:48:45,640 --> 00:48:50,890 And sometimes, the hypoiodous acid actually 783 00:48:50,890 --> 00:48:54,170 oxidizes iodide to iodine. 784 00:48:54,170 --> 00:48:56,720 So you've got collarless going to amber. 785 00:48:56,720 --> 00:49:00,650 But sometimes, there's so much hypoiodous acid formed, 786 00:49:00,650 --> 00:49:02,520 you can't handle everything. 787 00:49:02,520 --> 00:49:05,690 And what happens is you have a little bit of I 788 00:49:05,690 --> 00:49:08,300 minus and I2 present at the same time. 789 00:49:08,300 --> 00:49:09,957 And you get blue-black. 790 00:49:09,957 --> 00:49:11,540 This is kind of the color you're going 791 00:49:11,540 --> 00:49:13,250 to get when you do your titrations 792 00:49:13,250 --> 00:49:15,710 and you add the starch, because there 793 00:49:15,710 --> 00:49:19,670 is starch present in this. 794 00:49:19,670 --> 00:49:21,950 So I'm going to leave you with that. 795 00:49:21,950 --> 00:49:26,000 And I'll see some of you up in the lab. 796 00:49:26,000 --> 00:49:27,170 Yes, you have a question. 797 00:49:27,170 --> 00:49:29,120 AUDIENCE: [INAUDIBLE] 798 00:49:29,120 --> 00:49:32,630 JOHN DOLHUN: She just asked me if this will ever stop. 799 00:49:32,630 --> 00:49:35,470 Can someone-- Hannah wants to know 800 00:49:35,470 --> 00:49:37,520 if this is going to ever stop. 801 00:49:37,520 --> 00:49:43,050 Who can tell me, anyone? 802 00:49:43,050 --> 00:49:43,550 Aisha? 803 00:49:43,550 --> 00:49:46,175 AUDIENCE: I feel like it won't, because it's not releasing gas. 804 00:49:48,393 --> 00:49:50,810 JOHN DOLHUN: Aisha says it probably won't because it's not 805 00:49:50,810 --> 00:49:52,700 releasing gas. 806 00:49:52,700 --> 00:49:54,320 But in a minute, it's going to. 807 00:49:54,320 --> 00:49:57,080 Iodine vapor is going to start pouring out of it, 808 00:49:57,080 --> 00:50:00,470 and Tristan is going to carry it up to the lab in a bucket 809 00:50:00,470 --> 00:50:02,780 quickly. 810 00:50:02,780 --> 00:50:10,700 But in answer to Hannah's question is, will this stop? 811 00:50:10,700 --> 00:50:12,020 AUDIENCE: [INAUDIBLE] 812 00:50:12,020 --> 00:50:14,180 JOHN DOLHUN: Limiting reagent, right? 813 00:50:14,180 --> 00:50:17,220 There's always a limiting reagent. 814 00:50:17,220 --> 00:50:19,690 OK, see you.