In Memoriam to my father- Organic food as good prenatal care: agricultural threats to pregnancy, breast milk and infant development by Dr Sandra Steingraber

Organic farming to safeguard the (first) environment, Part I Ecologist and writer Sandra Steingraber talks about her late father’s conversion to organic farming, where babies come from, and the frightening links between agricultural chemicals, birth defects and other developmental abnormalities. My dad died a week ago today. I spent the last ten days of his life at his bedside, in a vigil of caring and love along with my mother and my sister, and of course that was the last time we would all be together as a family. So if you can imagine the scene, it’s aptly named Stark County, Illinois, the oxygen machine kind of chuffing away, and outside the window snow falling on the huge, two-mile corn and bean fields as they disappear into the horizon. Now Dad was a very conservative guy and I’m sure he voted a straight Republican ticket. When Rachel Carson published Silent Spring in 1962, my dad was convinced by Carson’s argument that the reckless overuse of pesticides was incoherent and irrational. And after it was all over I had a choice to make. I could either stay on and attend his memorial service, or I could come here to Asilomar as planned. In an odd way, deciding to honor my commitment to Eco-Farm and to all of you organic growers and farmers is also a tribute to my dad. Dad was a big believer in the merits of hard work, persistence and living up to one’s commitments. Once, years ago, when I was hugely pregnant and had car trouble, I had to cancel a speaking engagement in Pittsburgh with Clean Water Action. My dad was so horrified that he volunteered to drive me there himself. It would have been a 14-hour trip, one-way, at night. Now Dad was a very conservative guy. He grew up poor and lost his parents at a young age. He was a teenage combatant in World War II, along with his six brothers. He put himself through college on the GI bill, bought himself some land, built his own house, laid his own brick, put in an orchard, a vineyard and a garden so he’d never have to go hungry again. He had little tolerance for those in need of handouts. He worked as a business teacher in the local high school and I’m sure he voted a straight Republican ticket. Indeed the Red-Blue rift that runs through the entire country right now also ran through our relationship as father and daughter. But here’s what I want to say about my dad right now, which if I’m clever enough can segue into my lecture material. When Rachel Carson published Silent Spring in 1962, my dad immediately adopted the book as a text for his business class. He was convinced about the economic rationale for organic agriculture, and he was convinced by Carson’s argument that the reckless overuse of pesticides was incoherent and irrational.I was only three years old at the time, but I knew that the book must be important because my dad always had a copy of it in his briefcase and another on our coffee table. And there was other evidence too. The spray bottles in the garage, used to control insect pests on our cherry, peach and apple trees, disappeared. And instead, the postman began delivering air-hole-punched bags full of ladybugs and praying mantises. Dad built a compost pile. Steingraber circa 1970 Organic agriculture has come a long way. It’s powerful. It has the power to bridge the political gap between my father and myself and it had the power to bring me here today. By age seven, I was selling organic tomatoes at the end of the driveway and for those of you familiar with the essay I wrote for the Organic Trade Association last year, called The Ecology of Pizza, in which I traced all the ingredients in an organically grown pizza and a conventional pizza, you might recall that I describe in that essay in some detail my experience as a pediatric retailer of organic produce. There’s even a picture of me, circa 1970, taken by my father in the vegetable booth with my father’s hand-lettered sign that said, “Organic Tomatoes, 25 cents a pound.” That’s a pretty good deal, even then I think. In those days, I spent more time defining the word organic for my customers than I did sacking the produce and weighing it. A lot of people stopped just because they wanted to know what in the world the word organic meant. Organic agriculture has come a long way in the subsequent 40 years. It’s powerful. It has the power to bridge the political gap between my father and myself and it had the power to bring me here today. When I was approached recently by a publishing house to write a chapter on reasons for hope after the last election, I focused on organic agriculture. What else is there? Here’s a copy of that book. I think there will be copies that I can sign for you later on today, it’s called “What Do We Do Now?” and has folks like Howard Dean and Greg Pallast in it. My name appears right here on George Bush’s chin, which I consider a direct hit. But I did not show a copy of this to my dad. He wouldn’t have liked that. Having Faith When I was pregnant with my daughter Faith, to move on to the next generation, I had already spent 20 adult years mostly living my life out as a professional biologist and ecologist, which means I spent a lot of time studying the way organisms interact with the environments that they inhabit. So my first thought, and I don’t think it will come too much as a surprise to you, upon looking at that plastic stick on which I had just peed and seeing two lavender lines, indicating a positive pregnancy test, were, “Oh my God, now I’m a habitat.” And I immediately felt that inside me was this inland ocean with its population of one, this little sea mammal who was swimming around. At that point–as a lot of you know from [what is] probably my most well-known work, Living Downstream–I had been looking very closely at the role that environmental contaminants play in contributing to the causes of cancer. And I made a lateral move at that point in deciding to take a look at fetal toxicology, because it occurred to me that if the external environment is contaminated, so too is the internal environment of a woman’s body. And if a woman’s body is contaminated, then so too is the child that inhabits that body. It occurred to me that if the external environment is contaminated, so too is the internal environment of a woman’s body. And if a woman’s body is contaminated, then so too is the child that inhabits that body. As a biologist, I suspected that the kind of risks an individual would face in confronting those earliest exposures to things like pesticides would be unique, because at that point in fetal development of course the human body is just getting itself assembled. So the experience of my own pregnancy led me to Cornell University, where I began a four-year study of the field of fetal toxicology. So the research lasted far longer than my pregnancy with my daughter, and in fact the book that came [out] of it, which is the book that I want to talk to you out of now, Having Faith, was actually finished the week before I gave birth to my second child, which is a very good thing because one likes to finish one’s books on pregnancy before one’s actual pregnancies end because otherwise there’d be no time to write these kinds of things. So let’s talk a little bit about where babies come from. If your parents never did a good job in telling you this story, you’ll finally get it straight. When a sperm and an egg find each other in the upper reaches of the fallopian tube, it takes about a week for that little gondola boat to float down the Venetian canal of the fallopian tube and it kind of bobs out into the delta of the uterus, and it has to implant itself in the lining there. And that’s a process called implantation. At this point we’ve gone from a one-cell creature to a 58-cell creature, and those 58 cells are all organized as a ball of cells, and it’s called a “morula,” which is Latin for “mulberry,” which is exactly what this thing looks like. The first thing that has to happen in implantation is that the whole life support system for the pregnancy has to get established. Before we can start assembling a human body, we have to grow all the structures that are going to provide support for that body. We’re talking about things like the amnion, the chorion, the allantoic sac, the placenta, the umbilical cord, if those words sound familiar to you. After that, we can actually start forming the body. In the way that obstetricians and midwives date a pregnancy, the switch between growing the life support system and growing the actual human body begins at about week five of a human pregnancy, and the period that’s about to commence is called organogenesis. It goes on for five weeks, and by the end of week 10 of a human pregnancy you have a completely formed human being, about the size of a paper clip, and all the human body parts are present. Breast milk provides a lot more than just food. It actually has chemical messages to help the brain get wired up in the right way, and the immune system to modulate itself correctly and the gut to develop in the right way. Then what happens–and a pregnancy remember is about 40 weeks long–is the growth and development of all those body parts. So first you have implantation, which takes place about a week after the marriage of the sperm and the egg. Then you have organogenesis, and then you have growth and development, and that continues up until the very dramatic events of labor and delivery. What follows after that is a massive demolition and reconstruction project in which all of the blood flow going to the uterus–which has increased by fifty-fold during the human pregnancy–has to be taken apart and redirected up to the breasts, so that the breasts can take over from the placenta the job of nurturing the baby, and also providing growth factors and hormones and other chemical agents to help guide the development of the baby. Breast milk provides a lot more than just food. It actually has chemical messages to help the brain get wired up in the right way, and the immune system to modulate itself correctly and the gut to develop in the right way, etc. That redirection process takes between two to five days, so a baby’s actually born just living on air and then within two to five days after birth, the woman experiences the same thing a dairy cow does when she freshens–she experiences the sensation of her milk coming in, and at that point the symbiosis between mother and child is reestablished. So that’s where babies come from. New findings in fetal toxicology Now what I’d like to do is rewind the tape and go through that pregnancy again, only this time taking a look at all the windows of vulnerability that exist in which a toxic chemical–and I’ll focus on the ones in the agricultural sector–can enter into our story and threaten to sabotage it. The conceptual paradigm that emerges from this investigation–I’ll go ahead and give away my thesis right up front here–is that the new science of fetal toxicology is mounting an important challenge to the old way of thinking about toxicology. The old way of thinking, which goes back 500 years to a medieval monk named Paracelsus, who coined the phrase “the dose makes the poison,” has been the leading principle in the field of toxicology since the Middle Ages. What that means is that we assume there’s a safe level of exposure to a toxic chemical below which there is either no harm or transitory harm, and that through careful study in both laboratory animals and epidemiological studies of humans we can determine what the safe threshold level is. Those of you who know how we regulate pesticides will recognize that we have promulgated hundreds and hundreds of these food tolerance levels, and maximum contaminant levels for pesticides in drinking water, by which we try to police the food chain to make sure that no one of us is exposed to too much of these toxic pesticides–and all of them by definition are poisonous. Right? So the harm is considered negligible. But what has historically been overlooked both in Europe and the United States in the process of promulgating all these regulations, is the unique susceptibility during pregnancy and infancy and other key moments in a lifetime. And these also include adolescence and old age, which I hope I’ll have time to hit on here. The old thinking was that “the dose makes the poison.” The new thinking from fetal toxicology is that the timing makes the poison as much as the dose. So keep that conceptual framework in mind, that the old thinking was that “the dose makes the poison.” The new thinking from fetal toxicology is that the timing makes the poison as much as the dose–that there are times in our human development when some biological event is unfolding, and if a toxic exposure occurs during that time, you have a disproportionate risk for harm. Let’s just give you one example. All of us in this room right now have something called a blood-brain barrier that’s working pretty well to protect us from any pesticide residues on the food we ate today. Hopefully there weren’t too many, but as we all know even organic agriculture has drift from other kinds of agriculture, so we all got a little bit of pesticides in our diet today, I think. Our blood-brain barrier is working mightily to make sure that those pesticides don’t leave our blood stream and enter the gray matter of our brains, where they could do real harm. For the most part that blood-brain barrier works remarkably well. But you don’t get one until you’re six months old. It takes that long for that barrier, which when we’re born is permeable, to be able to discriminate and keep out neurological toxins like insecticides. So anyone in here younger than six months old is going to be disproportionately affected by exposure to pesticides. When babies or fetuses are exposed to certain kinds of insecticides they are exquisitely vulnerable to vanishingly small amounts. That’s what the most recent science is showing us, [and in doing so it’s] mounting a real challenge to the whole system of industrial agriculture right now. And it’ll be very interesting to see how this plays itself out. Chemical impacts on the viability of eggs and sperm So let’s just go back through a pregnancy and take a look at a few more examples. We’ll go back all the way to the eggs and the sperm. Let me say this first about human eggs. We know that women who smoke go into menopause on average two to three years earlier than women who don’t smoke, and we now know the reason for this: Smokers ingest high amounts of benzoate pyrene, which is a chemical in tobacco smoke. It’s the same one that happens to cause lung cancer. Benzoate pyrene cycles around in the bloodstream and when it gets into the ovary, it can actually insinuate itself into a human egg and flip genetic switches inside the DNA of human eggs. In so doing it can cause the cell to commit suicide—the biological term for that apoptosis. So a woman who’s a smoker uses up her viable eggs faster than a woman who doesn’t smoke, and if you know any teenage girls who are smokers, that might be the argument to use with them, because smoking does lower your fertility. We know the same is true with laboratory animals. As far as I’m concerned any chemical that messes with the menstrual cycle of women has no place in our agricultural system and should be phased out immediately. Researchers who are hot on this topic began to wonder–since benzoate pyrene is also found in diesel exhaust and other forms of air pollution–whether ambient air pollution might also be playing a role in shortening fertile life-spans among women. I don’t have an answer for you yet, but what I can tell you is that when we do experiments on laboratory animals we find that animals exposed to ambient levels of benzoate pyrene, such as we see in some of our major cities, suffer from shortened fertile life-spans through that same mechanism–their eggs die at a much faster rate than animals who breathe clean air. So it’ll be interesting to see how that plays itself out, and that’s an area of research to monitor. It has raised in the scientific community questions about what other kinds of chemicals, like agricultural chemicals, might be having the same affect in lowering fertility rates in women. Again I don’t have answers right now, but you might be interested to know it’s a hot area of research and investigation right now. We do know that the herbicide atrazene interferes with ovulation in all mammals. We don’t yet know whether that might play a role in lowering fertility in women. As far as I’m concerned any chemical that messes with the menstrual cycle of women has no place in our agricultural system and should be phased out immediately. Since we have such certainty about the ability of atrazene to interfere with the pituitary hormone that governs ovulation–there’s just no uncertainty about that, I think that’s something you can take out to your communities and talk about, just say, how much proof do you need? We are suppressing ovulation in laboratory animals exposed to atrazene. We know with some amount of certainty that women farmers exposed to atrazene have this interference of pituitary hormone to their ovaries. This is all we need to know to move to a safer form of farming. With sperm we have some more evidence. We know that men in Missouri who drink water from wells in rural areas with pesticide contamination have higher numbers of deformed sperm and slow sperm. There’s active research going on now to see if that means their partners have increased difficulty getting pregnant, but we definitely have an emerging body of evidence showing that exposure to pesticides in men seems to interfere with the vitality and viability of sperm. These are not farmers, these are not people who necessarily have other exposures. As far as we know their main exposure is simply through living in a rural area and drinking water that others have contaminated with agricultural chemicals. We are suppressing ovulation in laboratory animals exposed to atrazene. We know with some amount of certainty that women farmers exposed to atrazene have this interference of pituitary hormone to their ovaries. This is all we need to know to move to a safer form of farming. Let’s continue with our story, though, let’s assume that the egg and the sperm are fine and healthy, they find each other up there, they get married. Implantation happens next, about a week later. The risk here, if you introduce a toxic chemical into our story, is pregnancy loss, because the life support system doesn’t get established correctly and so the woman experiences a miscarriage. We do have a very good body of evidence showing that women exposed to solvents in the workplace, such as the computer chip industry, have higher than expected rates of miscarriage and pregnancy loss. We know that nitrogen fertilizer can do the same thing, and those findings again have sparked interest into asking whether other kinds of herbicide and pesticide exposures may also contribute to pregnancy loss. It’s a tricky question to answer because we don’t keep registries of miscarriages the way we keep birth defect registries and cancer registries. So a lot of this evidence is anecdotal, but there are researchers now moving into rural communities and trying to measure these things and find out what’s going on. So that’s another area of research to keep your eye on.

My dad died a week ago today. I spent the last ten days of his life at his bedside, in a vigil of caring and love along with my mother and my sister, and of course that was the last time we would all be together as a family. So if you can imagine the scene, it’s aptly named Stark County, Illinois, the oxygen machine kind of chuffing away, and outside the window snow falling on the huge, two-mile corn and bean fields as they disappear into the horizon. Now Dad was a very conservative guy and I’m sure he voted a straight Republican ticket. When Rachel Carson published Silent Spring in 1962, my dad was convinced by Carson’s argument that the reckless overuse of pesticides was incoherent and irrational. And after it was all over I had a choice to make. I could either stay on and attend his memorial service, or I could come here to Asilomar as planned. In an odd way, deciding to honor my commitment to Eco-Farm and to all of you organic growers and farmers is also a tribute to my dad. Dad was a big believer in the merits of hard work, persistence and living up to one’s commitments. Once, years ago, when I was hugely pregnant and had car trouble, I had to cancel a speaking engagement in Pittsburgh with Clean Water Action. My dad was so horrified that he volunteered to drive me there himself. It would have been a 14-hour trip, one-way, at night. Now Dad was a very conservative guy. He grew up poor and lost his parents at a young age. He was a teenage combatant in World War II, along with his six brothers. He put himself through college on the GI bill, bought himself some land, built his own house, laid his own brick, put in an orchard, a vineyard and a garden so he’d never have to go hungry again. He had little tolerance for those in need of handouts. He worked as a business teacher in the local high school and I’m sure he voted a straight Republican ticket. Indeed the Red-Blue rift that runs through the entire country right now also ran through our relationship as father and daughter. But here’s what I want to say about my dad right now, which if I’m clever enough can segue into my lecture material. When Rachel Carson published Silent Spring in 1962, my dad immediately adopted the book as a text for his business class. He was convinced about the economic rationale for organic agriculture, and he was convinced by Carson’s argument that the reckless overuse of pesticides was incoherent and irrational.I was only three years old at the time, but I knew that the book must be important because my dad always had a copy of it in his briefcase and another on our coffee table. And there was other evidence too. The spray bottles in the garage, used to control insect pests on our cherry, peach and apple trees, disappeared. And instead, the postman began delivering air-hole-punched bags full of ladybugs and praying mantises. Dad built a compost pile. Steingraber circa 1970 Organic agriculture has come a long way. It’s powerful. It has the power to bridge the political gap between my father and myself and it had the power to bring me here today. By age seven, I was selling organic tomatoes at the end of the driveway and for those of you familiar with the essay I wrote for the Organic Trade Association last year, called The Ecology of Pizza, in which I traced all the ingredients in an organically grown pizza and a conventional pizza, you might recall that I describe in that essay in some detail my experience as a pediatric retailer of organic produce. There’s even a picture of me, circa 1970, taken by my father in the vegetable booth with my father’s hand-lettered sign that said, “Organic Tomatoes, 25 cents a pound.” That’s a pretty good deal, even then I think. In those days, I spent more time defining the word organic for my customers than I did sacking the produce and weighing it. A lot of people stopped just because they wanted to know what in the world the word organic meant. Organic agriculture has come a long way in the subsequent 40 years. It’s powerful. It has the power to bridge the political gap between my father and myself and it had the power to bring me here today. When I was approached recently by a publishing house to write a chapter on reasons for hope after the last election, I focused on organic agriculture. What else is there? Here’s a copy of that book. I think there will be copies that I can sign for you later on today, it’s called “What Do We Do Now?” and has folks like Howard Dean and Greg Pallast in it. My name appears right here on George Bush’s chin, which I consider a direct hit. But I did not show a copy of this to my dad. He wouldn’t have liked that. Having Faith When I was pregnant with my daughter Faith, to move on to the next generation, I had already spent 20 adult years mostly living my life out as a professional biologist and ecologist, which means I spent a lot of time studying the way organisms interact with the environments that they inhabit. So my first thought, and I don’t think it will come too much as a surprise to you, upon looking at that plastic stick on which I had just peed and seeing two lavender lines, indicating a positive pregnancy test, were, “Oh my God, now I’m a habitat.” And I immediately felt that inside me was this inland ocean with its population of one, this little sea mammal who was swimming around. At that point–as a lot of you know from [what is] probably my most well-known work, Living Downstream–I had been looking very closely at the role that environmental contaminants play in contributing to the causes of cancer. And I made a lateral move at that point in deciding to take a look at fetal toxicology, because it occurred to me that if the external environment is contaminated, so too is the internal environment of a woman’s body. And if a woman’s body is contaminated, then so too is the child that inhabits that body. It occurred to me that if the external environment is contaminated, so too is the internal environment of a woman’s body. And if a woman’s body is contaminated, then so too is the child that inhabits that body. As a biologist, I suspected that the kind of risks an individual would face in confronting those earliest exposures to things like pesticides would be unique, because at that point in fetal development of course the human body is just getting itself assembled. So the experience of my own pregnancy led me to Cornell University, where I began a four-year study of the field of fetal toxicology. So the research lasted far longer than my pregnancy with my daughter, and in fact the book that came [out] of it, which is the book that I want to talk to you out of now, Having Faith, was actually finished the week before I gave birth to my second child, which is a very good thing because one likes to finish one’s books on pregnancy before one’s actual pregnancies end because otherwise there’d be no time to write these kinds of things. So let’s talk a little bit about where babies come from. If your parents never did a good job in telling you this story, you’ll finally get it straight. When a sperm and an egg find each other in the upper reaches of the fallopian tube, it takes about a week for that little gondola boat to float down the Venetian canal of the fallopian tube and it kind of bobs out into the delta of the uterus, and it has to implant itself in the lining there. And that’s a process called implantation. At this point we’ve gone from a one-cell creature to a 58-cell creature, and those 58 cells are all organized as a ball of cells, and it’s called a “morula,” which is Latin for “mulberry,” which is exactly what this thing looks like. The first thing that has to happen in implantation is that the whole life support system for the pregnancy has to get established. Before we can start assembling a human body, we have to grow all the structures that are going to provide support for that body. We’re talking about things like the amnion, the chorion, the allantoic sac, the placenta, the umbilical cord, if those words sound familiar to you. After that, we can actually start forming the body. In the way that obstetricians and midwives date a pregnancy, the switch between growing the life support system and growing the actual human body begins at about week five of a human pregnancy, and the period that’s about to commence is called organogenesis. It goes on for five weeks, and by the end of week 10 of a human pregnancy you have a completely formed human being, about the size of a paper clip, and all the human body parts are present. Breast milk provides a lot more than just food. It actually has chemical messages to help the brain get wired up in the right way, and the immune system to modulate itself correctly and the gut to develop in the right way. Then what happens–and a pregnancy remember is about 40 weeks long–is the growth and development of all those body parts. So first you have implantation, which takes place about a week after the marriage of the sperm and the egg. Then you have organogenesis, and then you have growth and development, and that continues up until the very dramatic events of labor and delivery. What follows after that is a massive demolition and reconstruction project in which all of the blood flow going to the uterus–which has increased by fifty-fold during the human pregnancy–has to be taken apart and redirected up to the breasts, so that the breasts can take over from the placenta the job of nurturing the baby, and also providing growth factors and hormones and other chemical agents to help guide the development of the baby. Breast milk provides a lot more than just food. It actually has chemical messages to help the brain get wired up in the right way, and the immune system to modulate itself correctly and the gut to develop in the right way, etc. That redirection process takes between two to five days, so a baby’s actually born just living on air and then within two to five days after birth, the woman experiences the same thing a dairy cow does when she freshens–she experiences the sensation of her milk coming in, and at that point the symbiosis between mother and child is reestablished. So that’s where babies come from. New findings in fetal toxicology Now what I’d like to do is rewind the tape and go through that pregnancy again, only this time taking a look at all the windows of vulnerability that exist in which a toxic chemical–and I’ll focus on the ones in the agricultural sector–can enter into our story and threaten to sabotage it. The conceptual paradigm that emerges from this investigation–I’ll go ahead and give away my thesis right up front here–is that the new science of fetal toxicology is mounting an important challenge to the old way of thinking about toxicology. The old way of thinking, which goes back 500 years to a medieval monk named Paracelsus, who coined the phrase “the dose makes the poison,” has been the leading principle in the field of toxicology since the Middle Ages. What that means is that we assume there’s a safe level of exposure to a toxic chemical below which there is either no harm or transitory harm, and that through careful study in both laboratory animals and epidemiological studies of humans we can determine what the safe threshold level is. Those of you who know how we regulate pesticides will recognize that we have promulgated hundreds and hundreds of these food tolerance levels, and maximum contaminant levels for pesticides in drinking water, by which we try to police the food chain to make sure that no one of us is exposed to too much of these toxic pesticides–and all of them by definition are poisonous. Right? So the harm is considered negligible. But what has historically been overlooked both in Europe and the United States in the process of promulgating all these regulations, is the unique susceptibility during pregnancy and infancy and other key moments in a lifetime. And these also include adolescence and old age, which I hope I’ll have time to hit on here. The old thinking was that “the dose makes the poison.” The new thinking from fetal toxicology is that the timing makes the poison as much as the dose. So keep that conceptual framework in mind, that the old thinking was that “the dose makes the poison.” The new thinking from fetal toxicology is that the timing makes the poison as much as the dose–that there are times in our human development when some biological event is unfolding, and if a toxic exposure occurs during that time, you have a disproportionate risk for harm. Let’s just give you one example. All of us in this room right now have something called a blood-brain barrier that’s working pretty well to protect us from any pesticide residues on the food we ate today. Hopefully there weren’t too many, but as we all know even organic agriculture has drift from other kinds of agriculture, so we all got a little bit of pesticides in our diet today, I think. Our blood-brain barrier is working mightily to make sure that those pesticides don’t leave our blood stream and enter the gray matter of our brains, where they could do real harm. For the most part that blood-brain barrier works remarkably well. But you don’t get one until you’re six months old. It takes that long for that barrier, which when we’re born is permeable, to be able to discriminate and keep out neurological toxins like insecticides. So anyone in here younger than six months old is going to be disproportionately affected by exposure to pesticides. When babies or fetuses are exposed to certain kinds of insecticides they are exquisitely vulnerable to vanishingly small amounts. That’s what the most recent science is showing us, [and in doing so it’s] mounting a real challenge to the whole system of industrial agriculture right now. And it’ll be very interesting to see how this plays itself out. Chemical impacts on the viability of eggs and sperm So let’s just go back through a pregnancy and take a look at a few more examples. We’ll go back all the way to the eggs and the sperm. Let me say this first about human eggs. We know that women who smoke go into menopause on average two to three years earlier than women who don’t smoke, and we now know the reason for this: Smokers ingest high amounts of benzoate pyrene, which is a chemical in tobacco smoke. It’s the same one that happens to cause lung cancer. Benzoate pyrene cycles around in the bloodstream and when it gets into the ovary, it can actually insinuate itself into a human egg and flip genetic switches inside the DNA of human eggs. In so doing it can cause the cell to commit suicide—the biological term for that apoptosis. So a woman who’s a smoker uses up her viable eggs faster than a woman who doesn’t smoke, and if you know any teenage girls who are smokers, that might be the argument to use with them, because smoking does lower your fertility. We know the same is true with laboratory animals. As far as I’m concerned any chemical that messes with the menstrual cycle of women has no place in our agricultural system and should be phased out immediately. Researchers who are hot on this topic began to wonder–since benzoate pyrene is also found in diesel exhaust and other forms of air pollution–whether ambient air pollution might also be playing a role in shortening fertile life-spans among women. I don’t have an answer for you yet, but what I can tell you is that when we do experiments on laboratory animals we find that animals exposed to ambient levels of benzoate pyrene, such as we see in some of our major cities, suffer from shortened fertile life-spans through that same mechanism–their eggs die at a much faster rate than animals who breathe clean air. So it’ll be interesting to see how that plays itself out, and that’s an area of research to monitor. It has raised in the scientific community questions about what other kinds of chemicals, like agricultural chemicals, might be having the same affect in lowering fertility rates in women. Again I don’t have answers right now, but you might be interested to know it’s a hot area of research and investigation right now. We do know that the herbicide atrazene interferes with ovulation in all mammals. We don’t yet know whether that might play a role in lowering fertility in women. As far as I’m concerned any chemical that messes with the menstrual cycle of women has no place in our agricultural system and should be phased out immediately. Since we have such certainty about the ability of atrazene to interfere with the pituitary hormone that governs ovulation–there’s just no uncertainty about that, I think that’s something you can take out to your communities and talk about, just say, how much proof do you need? We are suppressing ovulation in laboratory animals exposed to atrazene. We know with some amount of certainty that women farmers exposed to atrazene have this interference of pituitary hormone to their ovaries. This is all we need to know to move to a safer form of farming. With sperm we have some more evidence. We know that men in Missouri who drink water from wells in rural areas with pesticide contamination have higher numbers of deformed sperm and slow sperm. There’s active research going on now to see if that means their partners have increased difficulty getting pregnant, but we definitely have an emerging body of evidence showing that exposure to pesticides in men seems to interfere with the vitality and viability of sperm. These are not farmers, these are not people who necessarily have other exposures. As far as we know their main exposure is simply through living in a rural area and drinking water that others have contaminated with agricultural chemicals. We are suppressing ovulation in laboratory animals exposed to atrazene. We know with some amount of certainty that women farmers exposed to atrazene have this interference of pituitary hormone to their ovaries. This is all we need to know to move to a safer form of farming. Let’s continue with our story, though, let’s assume that the egg and the sperm are fine and healthy, they find each other up there, they get married. Implantation happens next, about a week later. The risk here, if you introduce a toxic chemical into our story, is pregnancy loss, because the life support system doesn’t get established correctly and so the woman experiences a miscarriage. We do have a very good body of evidence showing that women exposed to solvents in the workplace, such as the computer chip industry, have higher than expected rates of miscarriage and pregnancy loss. We know that nitrogen fertilizer can do the same thing, and those findings again have sparked interest into asking whether other kinds of herbicide and pesticide exposures may also contribute to pregnancy loss. It’s a tricky question to answer because we don’t keep registries of miscarriages the way we keep birth defect registries and cancer registries. So a lot of this evidence is anecdotal, but there are researchers now moving into rural communities and trying to measure these things and find out what’s going on. So that’s another area of research to keep your eye on.