Tyrone Hayes | |
---|---|
Born | Columbia, South Carolina, U.S. | July 29, 1967
Education | Harvard University (BA, MA) University of California, Berkeley (PhD) |
Occupation | Professor |
Tyrone B. Hayes (born July 29, 1967) is an American biologist and professor of integrative biology at the University of California, Berkeley. He is known for his research in frogs, concluding that the herbicide atrazine is an endocrine disruptor that demasculinizes male frogs, causing them to display female characteristics. Hayes is an advocate for the critical review and regulation of pesticides as well as other chemicals that may cause adverse health effects. He has presented hundreds of papers, discussions, and seminars on his research's conclusion that environmental contaminants have played a major role in the global amphibian decline as well as being linked to the many health disparities that occur in minority and low income populations.
Hayes' research into atrazine as an endocrine disruptor has been contested by Syngenta – the company who manufactures atrazine – and the Australian Pesticides and Veterinary Medicines Authority.
In 2023, he was elected to the National Academy of Sciences. [1] [2]
Tyrone Hayes was born in 1967 in Columbia, South Carolina to Romeo and Susie Hayes. As a child he showed great interest in lizards and frogs. He was particularly interested in the way frogs morphed from tadpoles into their adult form. He won a state science fair with research that showed that anole lizards had to be awake in order to change color. [3] He graduated from Dreher High School in 1985 and earned both his A.B. and M.A. in biology in 1989 from Harvard University. His dissertation focused on the genetic and environmental mechanisms determining the gender of the wood frog. He continued his studies at the University of California, Berkeley. There he received his Ph.D. in integrative biology in 1993 for his study of the role that hormone play in mediating developmental responses to environmental changes in amphibians. [4]
After graduating from Harvard University, Hayes worked as a technician and freelance consultant from 1990 to 1992 for Tiburon, California-based Biosystems, Inc. [5] Hayes has held an academic appointment (professorship) at the University of California, Berkeley since completing his doctoral research there in 1992; [3] he was hired as a graduate student instructor in 1992, became an assistant professor in 1994, associate professor in 2000, and professor in 2003 in the Department of Integrative Biology, Molecular Toxicology, Group in Endocrinology, Museum of Vertebrate Zoology, Energy and Resources Group, University of California, Berkeley. [5] In 2021, Hayes was appointed to the position of Department Co-Chair. He advanced to the position of associate dean for Diversity, Equity and Inclusion in the College of Letters and Science at Berkeley in 2023. [1]
Hayes’ scientific research has focused on the potential of genetic adaptation and the role of hormones in the development of the amphibian. His investigations have shown that chemical agents, such as a commonly used herbicide, have the ability to negatively impact the sexual development of the amphibian, even when such toxins are present in low concentrations. Hayes has taken an interest in the hormonal regulation and development of aggressive behavior. He has also been active with the National Science Foundation Review Panel since 1995, and he has served on several other advisory boards as well.
In 1997, the consulting firm EcoRisk, Inc. paid Hayes to join a panel of experts conducting studies for the Swiss pharmaceutical company Novartis (later Syngenta) on the herbicide atrazine. [3] [6] When Hayes' research found unexpected toxicities for atrazine, he reported them to the panel, however the panel and company were resistant to his findings. He wanted to repeat his work to validate it but Novartis refused funding for further research; he resigned from the panel and obtained other funding to repeat the experiments. [3] [6]
In 2002 Hayes published findings that he says replicate what he found while he was working for EcoRisk, [3] that developing male African clawed frogs and leopard frogs exhibited female characteristics after exposure to atrazine, first in the Proceedings of the National Academy of Sciences (PNAS) [7] and then in Nature. [8] [9]
In 2007, Hayes was a co-author on a paper that detailed atrazine inducing mammary and prostate cancer in laboratory rodents and highlighted atrazine as a potential cause of reproductive cancers in humans. [10] In 2007, Hayes presented results of his studies to the U.S. National Institute of Environmental Health Sciences showing chemical castration in frogs; individuals of both sexes had developed bisexual reproductive organs. [11] In 2010, Hayes published research in PNAS [12] describing laboratory work showing how exposure to atrazine turned male tadpoles into females with impaired fertility. [6]
The U.S. Environmental Protection Agency (EPA) and its independent Scientific Advisory Panel (SAP) examined all available studies on this topic and concluded that "atrazine does not adversely affect amphibian gonadal development based on a review of laboratory and field studies." [13] The EPA and its SAP made recommendations concerning proper study design needed for further investigation into this issue. As required by the EPA, two experiments were conducted under Good Laboratory Practices (GLP) and inspection by the EPA and German regulatory authorities. The paper concluded "These studies demonstrate that long-term exposure of larval X. laevis to atrazine at concentrations ranging from 0.01 to 100 microg/l does not affect growth, larval development, or sexual differentiation." [14] A report written in Environmental Science and Technology (May 15, 2008) cites the independent work of researchers in Japan, who were unable to replicate Hayes' work. "The scientists found no hermaphrodite frogs; no increase in aromatase as measured by aromatase mRNA induction; and no increase in vitellogenin, another marker of feminization." [15] In 2010, the Australian Pesticides and Veterinary Medicines Authority (APVMA) responded to Hayes' 2010 published paper, [16] by stating that his findings "do not provide sufficient evidence to justify a reconsideration of current regulations which are based on a very extensive dataset." [17]
Since publishing his research on atrazine as an endocrine disruptor, Hayes has become an advocate for banning atrazine. [18] According to Hayes, the link between atrazine and altered "aromatase and estrogen production has been demonstrated... in fish, frogs, alligators, birds, turtles, rats and human cells", and, "I believe that the preponderance of the evidence shows atrazine to be a risk to wildlife and humans. I would not want to be exposed to it, nor do I think it should be released into the environment." [18] [19] He travels and lectures extensively to both scientific and lay audiences. [6]
He also has raised issues of environmental racism, warning that "if you’re black or Hispanic, you’re more likely to live or work in areas where you’re exposed to crap". [6] While a biologist on the Public Broadcasting Service, National Geographic program Strange Days, he expressed his concerns for human health, particularly that of minority and low-paid workers exposure to agricultural chemicals. [20]
Research published by Hayes and other scientists was used as evidence in a class action lawsuit against Syngenta by 15 water providers in Illinois that was settled for 105 million dollars in May 2012, [9] [21] [22] which reimbursed more than 1,000 water systems for the costs of filtering atrazine from drinking water, although the company denies any wrongdoing. [6] [23]
A long running conflict between Hayes and agricultural chemical manufacturer Syngenta was described as "one of the weirdest feuds in the history of science,” by Dashka Slater in her 2012 profile of Hayes in Mother Jones magazine. [3] [24]
In 2014, New Yorker writer Rachel Aviv reported that Syngenta might have been orchestrating an attack not only on Hayes' scientific credibility, but on other scientists as well whose studies have shown atrazine to have adverse effects on the environment and/or human and animal health. [6]
Aviv reported that Syngenta had criticized Hayes' science and conduct in press releases, letters to the editor, and through a formal ethics complaint filed at University of California-Berkeley. [6] Internal Syngenta documents from 2005 released by a class-action lawsuit in 2014 show ways that Syngenta conspired to discredit Hayes, including attempting to get journals to retract his work, and investigating his funding and private life. [6] [25] [26] In one of the 2005 e-mails obtained by class-action lawsuit plaintiffs, the company's communications consultants had written about plans to track Hayes' speaking engagements and prepare audiences with Syngenta's counterpoints to Hayes's message on atrazine. Syngenta subsequently stated that many of the documents unsealed in the lawsuits refer to "ideas that were never implemented." [6]
In 2010, Syngenta forwarded an ethics complaint to the University of California Berkeley, complaining that Hayes had been sending sexually explicit and harassing e-mails to Syngenta scientists, including quoting the rapper DMX. [27] Some of these emails were obtained and published by Gawker . [28] Legal counsel from the university responded that Hayes had acknowledged sending letters having "unprofessional and offensive" content, and that he had agreed not to use similar language in future communications. [27] [29] According to Hayes, the situation had escalated after Syngenta executive Tim Pastoor had threatened Hayes and his family. [30]
Hayes' work was featured in the 2008 documentary film Flow: For Love of Water . [31] In 2010, Hayes and filmmaker Penelope Jagessar Chaffer were featured on a TED Talk together for TEDWomen, discussing chemical exposure in pregnancy, in light of Jagessar's film: Toxic Baby. [32] He appeared in the 2012 documentary film Last Call at the Oasis. [33] [34] Hayes is the subject of The Frog Scientist, a biographical book for children, first published in 2009. [35] Hayes appeared in another TED Talk in 2018. This talk centered around Hayes' early interest in science - particularly frogs - as well as his career development, research in endocrine disruption, his ongoing feud with Synenta, and the disproportionate way environmentally harmful chemicals affect the lives of minorities and the poor. [36] In 2019, Hayes was the subject of the children's book, "There's Something in the Water", published by the nonprofit STEM4Real. The book focuses on Tyrone's early life and how his observations as a young child fueled his passion for studying frogs. [37]
Hayes lives in California with his wife, Kathy Kim. He has won several awards for his teaching and his research, including the Distinguished Teaching Award from University of California, Berkeley in 2002 and the President's Citation Award from the American Institute of Biological Science in 2004. He was also awarded the National Geographic Emerging Explorer Award and the Jennifer Altman Award in 2005. [4]
Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Its herbicidal effectiveness was discovered by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.
Piperonyl butoxide (PBO) is a pale yellow to light brown liquid organic compound used as an adjuvant component of pesticide formulations for synergy. That is, despite having no pesticidal activity of its own, it enhances the potency of certain pesticides such as carbamates, pyrethrins, pyrethroids, and rotenone. It is a semisynthetic derivative of safrole and is produced from the condensation of the sodium salt of 2-(2-butoxyethoxy) ethanol and the chloromethyl derivative of hydrogenated safrole (dihydrosafrole); or through 1,2-Methylenedioxybenzene.
Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine systems. These disruptions can cause numerous adverse human health outcomes, including alterations in sperm quality and fertility; abnormalities in sex organs‚ endometriosis‚ early puberty‚ altered nervous system or immune function; certain cancers; respiratory problems; metabolic issues; diabetes, obesity, or cardiovascular problems; growth, neurological and learning disabilities, and more. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis ."
Paraquat (trivial name; ), or N,N′-dimethyl-4,4′-bipyridinium dichloride (systematic name), also known as methyl viologen, is an organic compound with the chemical formula [(C6H7N)2]Cl2. It is classified as a viologen, a family of redox-active heterocycles of similar structure. This salt is one of the most widely used herbicides. It is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic (lethal) to human beings and animals due to its redox activity, which produces superoxide anions. It has been linked to the development of Parkinson's disease and is banned in 58 countries.
In oviparous biology, a hatchling is a newly hatched fish, amphibian, reptile, or bird. A group of mammals called monotremes lay eggs, and their young are hatchlings as well.
Alachlor is an herbicide from the chloroacetanilide family. It is an odorless, white solid. The greatest use of alachlor is for control of annual grasses and broadleaf weeds in crops. Use of alachlor is illegal in the European Union and no products containing alachlor are currently registered in the United States.
Atrazine is a chlorinated herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), soybean and sugarcane and on turf, such as golf courses and residential lawns. Atrazine's primary manufacturer is Syngenta and it is one of the most widely used herbicides in the United States, Canadian, and Australian agriculture. Its use was banned in the European Union in 2004, when the EU found groundwater levels exceeding the limits set by regulators, and Syngenta could not show that this could be prevented nor that these levels were safe.
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
Syngenta is a global agricultural technology company headquartered in Basel, Switzerland. It primarily covers crop protection and seeds for farmers. Syngenta is part of the Syngenta Group, entirely owned by Sinochem, a Chinese state-owned enterprise.
Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. It became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. Because of its threats to human health and the environment, a global ban on the manufacture and use of endosulfan was negotiated under the Stockholm Convention in April 2011. The ban took effect in mid-2012, with certain uses exempted for five additional years. More than 80 countries, including the European Union, Australia, New Zealand, several West African nations, the United States, Brazil, and Canada had already banned it or announced phase-outs by the time the Stockholm Convention ban was agreed upon. It is still used extensively in India and China despite laws against its use. It is also used in a few other countries. It is produced by the Israeli firm Makhteshim Agan and several manufacturers in India and China. On May 13, 2011, the India Supreme Court ordered a ban on the production and sale of endosulfan in India, pending further notice.
Acetochlor is an herbicide developed by Monsanto Company and Zeneca. It is a member of the class of herbicides known as chloroacetanilides. Its mode of action is elongase inhibition, and inhibition of geranylgeranyl pyrophosphate (GGPP) cyclization enzymes, part of the gibberellin pathway. It carries high risks of environmental contamination.
Environmental toxicology is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels.
Pesticide drift, also known as spray drift refers to the unintentional diffusion of pesticides toward nontarget species. It is one of the most negative effects of pesticide application. Drift can damage human health, environment, and crops. Together with runoff and leaching, drift is a mechanism for agricultural pollution. Some drift results from contamination of sprayer tanks.
The environmental effects of pesticides describe the broad series of consequences of using pesticides. The unintended consequences of pesticides is one of the main drivers of the negative impact of modern industrial agriculture on the environment. Pesticides, because they are toxic chemicals meant to kill pest species, can affect non-target species, such as plants, animals and humans. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, because they are sprayed or spread across entire agricultural fields. Other agrochemicals, such as fertilizers, can also have negative effects on the environment.
Pesticides in the United States are used predominantly by the agricultural sector, but approximately a quarter of them are used in houses, yards, parks, golf courses, and swimming pools.
Health effects of pesticides may be acute or delayed in those who are exposed. Acute effects can include pesticide poisoning, which may be a medical emergency. Strong evidence exists for other, long-term negative health outcomes from pesticide exposure including birth defects, fetal death, neurodevelopmental disorder, cancer, and neurologic illness including Parkinson's disease. Toxicity of pesticides depend on the type of chemical, route of exposure, dosage, and timing of exposure.
Xenohormones or environmental hormones are compounds produced outside of the human body which exhibit endocrine hormone-like properties. They may be either of natural origin, such as phytoestrogens, which are derived from plants, or of synthetic origin. These compounds can cause endocrine disruption by multiple mechanisms including acting directly on hormone receptors, affecting the levels of natural hormones in the body, and by altering the expression of hormone receptors. The most commonly occurring xenohormones are xenoestrogens, which mimic the effects of estrogen. Other xenohormones include xenoandrogens and xenoprogesterones. Xenohormones are used for a variety of purposes including contraceptive & hormonal therapies, and agriculture. However, exposure to certain xenohormones early in childhood development can lead to a host of developmental issues including infertility, thyroid complications, and early onset of puberty. Exposure to others later in life has been linked to increased risks of testicular, prostate, ovarian, and uterine cancers.
Glyphosate-based herbicides are usually made of a glyphosate salt that is combined with other ingredients that are needed to stabilize the herbicide formula and allow penetration into plants. The glyphosate-based herbicide Roundup was first developed by Monsanto in the 1970s. It is used most heavily on corn, soy, and cotton crops that have been genetically modified to be resistant to the herbicide. Some products include two active ingredients, such as Enlist Duo which includes 2,4-D as well as glyphosate. As of 2010, more than 750 glyphosate products were on the market. The names of inert ingredients used in glyphosate formulations are usually not listed on the product labels.
Cyanazine is a herbicide that belongs to the group of triazines. Cyanazine inhibits photosynthesis and is therefore used as a herbicide.
Conspiracy theories alleging that governments are using endocrine disrupting chemical pollutants in the water supply to create an alleged increase in the gay, bisexual or transgender population were popularized in the 2010s. Most notably, American conspiracy theorist Alex Jones cited research on the effects of atrazine on frogs, which can induce spontaneous sex change or hermaphroditism, claiming that US government was "putting chemicals in the water that turn the friggin’ frogs gay" as part of a "chemical warfare operation" or "gay bomb" to increase homosexuality and suppress birth rates. However, frogs have the ability to spontaneously change sex in non-polluted waterways in response to changes in temperature.
I could take tap water that is regulated by the U.S. EPA," Hayes noted, "and I could chemically castrate frogs.
I am concerned about the adverse impacts of Atrazine on endangered species and on racial/ethnic minorities. Prostate and breast cancer are two of the top causes of death in Americans age 25-40, but in particular Black and Hispanic Americans are several times more likely to die from these diseases. Ethnic minorities and people of low income are also more likely to hold the "unskilled" laborer positions in agriculture and pesticide production that would put them at higher risk of exposure and are least likely to have access to the emerging science demonstrating the dangers of exposure. Thus, this environmental and public health issue is also a racial/social justice issue because minority and working class people are the primary targets of pesticide exposure.
Tyrone Hayes, a biologist, shows us mutant frogs, their endocrine systems scrambled by pesticide-borne chemicals.
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