Rolf Halden: Hello every­body, and wel­come. What hap­pens to the germ-killing chem­i­cals that are added by the mil­lions of pounds to antimi­cro­bial and antibac­te­r­i­al con­sumer prod­ucts? The worst-case sce­nario in the spir­it of Murphy’s Law, where we have a chem­i­cal, we design it and we think it’s awe­some. We make mil­lions of pounds of it. And then we add it to thou­sands of con­sumer prod­ucts, only to find out after the fact that the chem­i­cal did not serve the pur­pose it was added for, and it turned out to be per­sis­tent and con­t­a­m­i­nat­ing our envi­ron­ment, our wildlife, and our­selves, caus­ing tox­ic effects. 

My team stud­ied and found not only one such chem­i­cal, but two such chem­i­cals. The chem­i­cals are called tri­closan and tri­clo­car­ban. I see a bland look so you prob­a­bly don’t know what that means. But even if you have not heard the names of these chem­i­cals, they are the chem­i­cals that make our con­sumer prod­ucts antimi­cro­bial and antibac­te­r­i­al. So if you have ever picked up a prod­uct that said it’s antimi­cro­bial, whether it is a tent, a sock, a shoe, a deter­gent, a deodor­ant, then you are guilty as charged. 

So when we wash our hands, if we wash them at all, it takes about six sec­onds, okay. And that amount of time on aver­age is just too short in order to give us a ben­e­fit if antimi­cro­bials are present in our soap. So the chem­i­cals are ren­dered use­less and are flushed down the drains in our kitchens and in our bath­rooms. And there they go on their mer­ry way toward the waste­water treat­ment plant. 

But sad­ly in the envi­ron­ment, once the chem­i­cals were out there, ani­mals were exposed for very long peri­ods of time. Even life­long, and for gen­er­a­tions, we found. And this we found out by look­ing at sur­face water sed­i­ments. And so by going down into the sed­i­ment core, we were able to do some time trav­el. And we found that organ­isms had been bathing in antimi­cro­bials ever since we start­ed pro­duc­ing them in the late 1950s and the 1960s. Antimicrobials don’t real­ly like water, and they like to seek shel­ter. And they seek shel­ter in liv­ing organisms. 

So, looks like we have con­t­a­m­i­nat­ed every­thing. What about out­er space? We had an oppor­tu­ni­ty to ana­lyze water from the International Space Station. And guess what we found in the water loop: antimi­cro­bial chemicals. 

So you see we have an omnipres­ence of antimi­cro­bial chem­i­cals. We can­not escape them any­more. They are in our water, in our air, in our soil, in our food. They are in the wildlife and they are in us. But iron­i­cal­ly, they are much more effec­tive in killing things oth­er than microor­gan­isms. We should call them antial­gal agents, or antiplank­ton­ic agents, or fish-killers. All of these names would be bet­ter than the name that we use today.

So if we want to under­stand the life cycle of the chem­i­cals, and the tox­i­c­i­ty, we have to look at the begin­ning. When we syn­the­size them, we already make super tox­ic, car­cino­genic diox­ins. They are part of the antimi­cro­bials. And then at the end of the life cycle of the chem­i­cal, when they fall apart, one sin­gle mol­e­cule can make two car­cino­gens if it falls apart. 

But the chem­i­cals also are tox­ic by them­selves in their own right. And among the many effects that antimi­cro­bials can have, the one thing that we are real­ly con­cerned about is endocrine dis­rup­tion. This is a scram­bling of the mes­sag­ing sys­tem in liv­ing organ­isms. Animal stud­ies have shown that small con­cen­tra­tions of antimi­cro­bials can lead to mal­for­ma­tion of repro­duc­tive organs, low­ered sperm count, spon­ta­neous abor­tion, an increase in aller­gies, and changes in metab­o­lism that can lead to obesity. 

And when microor­gan­isms are exposed to antimi­cro­bials and sur­vive it, they can become tough, they can become superbugs. And so some stud­ies have shown that if a pathogen is exposed to tri­closan, the organ­ism gets resis­tant not only to the antimi­cro­bial but also to antibi­otics. And not just one but six; half a dozen antibi­otics that are used in clin­ics and hos­pi­tals around the world to pre­vent peo­ple from los­ing their limbs and lives from micro­bial infections. 

Why did­n’t we ban the chem­i­cals in the first place? It turns out in the 1950s and 60s we did­n’t have the right tools to ful­ly under­stand the impact of these chem­i­cals on our phys­i­ol­o­gy and on the envi­ron­ment. And things like genome sequenc­ing, or epi­ge­net­ics, or even endocrine dis­rup­tion weren’t under­stood or dis­cov­ered at the time. It’s also true that in America we do a lim­it­ed amount of test­ing of chem­i­cals before they reach the mar­ket. Oftentimes the assump­tion is that the chem­i­cal is safe until proven harm­ful. In Europe peo­ple typ­i­cal­ly do more safe­ty test­ing, and they have some­thing that’s called the pre­cau­tion­ary prin­ci­ple, which says that if some­thing could be poten­tial­ly real­ly bad but we don’t have enough infor­ma­tion, we’d much rather not use it. 

But on both sides of the Atlantic, there is a leg­isla­tive back­door that allowed tri­closan and tri­clo­car­ban to slip into con­sumer prod­ucts and ulti­mate­ly into our bod­ies. And that door is the ​“grand­fa­ther­ing” process. Once we make chem­i­cals for a long time, we don’t have to test them again when new reg­u­la­tions come out. So they are grand­fa­thered in and they cir­cum­vent the test­ing that might have revealed some of their effects. 

How long does it take to ban a chem­i­cal? On September 2^nd of 2016, the United States Food and Drug Administration announced a ban of tri­closan, tri­clo­car­ban, and many oth­er antimi­cro­bial chem­i­cals. It has tak­en four­teen years between our dis­cov­ery of tri­clo­car­ban in urban streams in Baltimore to the ban of antimi­cro­bials that will take effect in 2017. Today tri­closan and tri­clo­car­ban are the top ten pol­lu­tants of our drink­ing water resources. 

So soon, the dark cloud of antimi­cro­bial pol­lu­tion should lift from the United States. But what about oth­er coun­tries? Over 200 sci­en­tists have signed our call to action, The Florence state­ment on Triclosan and Triclocarban, and it calls for removal of these chem­i­cals from all con­sumer prod­ucts where they don’t have a ben­e­fit, around the world. 

Unfortunately my stu­dents and I, by help­ing to get these chem­i­cals banned, worked our­selves out of our job. That is actu­al­ly not entire­ly true because there are a lot of chem­i­cals in com­mer­cial use, actu­al­ly 70,000 or so in America alone, and every year we intro­duce 2,000 chem­i­cals more. So there’s plen­ty of work to be done to scan the ever-expanding chem­i­cal hori­zons to look for, among this very use­ful and life-saving and con­ve­nient chem­istry, the few bad play­ers that might do us in. So this is our job and we try to keep you safe and healthy. And so with this, I hope I did­n’t scare you too much but I give you a lit­tle bit of appre­ci­a­tion for chem­istry. So remem­ber, next time when you enjoy a deli­cious meal, great com­pa­ny, and maybe even love, it’s all about good chem­istry. Thanks for listening.