The way scientists think about how chemicals cause their toxic effects is changing. Recent scientific research tells us that the traditional notion of how chemicals act is being replaced by a better understanding of the actual features of exposures to environmental chemicals. These features include the timing and vulnerability of exposures, exposures to mixtures, effects at low doses and genetic alterations called epigenetics.
Traditional thinking tells us that how much of a chemical you are exposed to (the dose) determines the effect. This principle assumes that chemicals act by overwhelming the body’s defenses at high doses. We’re learning now that this principle is not always accurate and its place in evaluating risks needs to be reconsidered. What we now know is that some chemicals cause their adverse effects at low exposure levels that are not predicted by classic toxicology.
Recent research has shown that environmental chemicals like dioxin or bisphenol A can alter genetic make-up, dramatically in some cases. These changes are so powerful that they can alter the genetic material in eggs and sperm and pass along new traits in a single generation, essentially by-passing evolution.
It wasn’t too long ago that scientists believed that the DNA in our cells was set for life, that our genes would be passed on from one generation to the next, and that it would take generations to change our genetic makeup. That’s no longer the case.
This new field – called epigenetics – is perhaps the fastest growing field in toxicology and it’s changing the way we think about chemical exposures and the risks they pose. Epigenetics is the study of changes in DNA expression (the process of converting the instructions in DNA into a final product, such as blue eyes or brown hair) that are independent of the DNA sequence itself.
What researchers are learning is that the “packaging” of the DNA is just as important as a person’s genetic make-up in determining a person’s observable traits, such as blue eyes, or their susceptibility to diseases such as adult on-set diabetes, or to the development of lupus.
The environment is a critical factor in the control of these packaging processes. We may be born with our genes, but epigenetics changes occur because of environmental influences during development and throughout life. These influences include chemicals in the food we eat, the air we breathe, the water we drink, and they appear to contribute to the development of cancer and other diseases.
Epigenetics may explain certain scientific mysteries, such as why certain people develop diseases and others don’t, or why the person who smoked for 30 years never developed lung cancer. There is still much to learn, but an early lesson to take away from this emerging science is that we need to rethink our traditional ideas of how chemicals affect our health.
For more information see
https://www.healthandenvironment.org/environmental-health/social-context/gene-environment-interactions
Tag: EPA
EPA has almost finished clearing arsenic-contaminated soil at a Superfund site in Southern Minneapolis. The soil became contaminated after an industrial pesticide storage site leached into local soil, affecting 600 homes. This represents the conclusion of EPA’s $25 million project to clean the Superfund site. <Read more>
by Liz Goodiel, CHEJ Science & Tech Fellow
This Friday, August 2, 2019 marks the anniversary of the historic evacuation of Love Canal. The landmark tragedy sparked an awareness across the nation to the environmental dangers present in everyday communities. The unfortunate reality of this event remains that the Love Canal is not an isolated event. Throughout the last half a century numerous towns and cities have come forward with cases of bad pollution. Despite decades of education and awareness, toxic tragedies have occurred and continue to occur in locations across the country. Many communities to date are still organizing together to fight similar incidents as Love Canal and continue to face challenges in their effort to achieve remediation or evacuation status.
Love Canal was an idyllic vision established by William T. Love in 1982 as paradise community connected to Niagara Falls by a canal. Due to economic failures, the canal project was abandoned and converted into a municipal and chemical waste dumping site by the Hooker Chemical Corporation and the City of Niagara. In 1953 the Hooker Chemical Corporation turned the land over the city where the canal was covered up, along with the secret chemicals it housed, and the construction of a new community began. With an understanding that the area was perfectly safe for residence, hundreds of homes were built as families migrated into the area.
Nearly 20 years later, the city disclosed information regarding the toxins present in the community, its subsequent health effects, and no details about how the government was going to right the wrong. Lois Gibbs, along with her neighbors, united over their shared frustration and general concern for their exposed families and established the Love Canal Parents Movement. Together the group voiced their concern and fought for change that finally came on August 2, 1978. The New York State Department of Health ordered the evacuation of pregnant women and children under the age of two to be evacuated. Just five days later, the rest of the community received relief as the government agreed to buy all 239 homes closest to the center of the canal.
Following the Love Canal evacuation, other communities began receiving attention in response to harmful pollutants poisoning the residents. One similar instance occurred only a few years later on the opposite side of the country. San Jose, California, a seemingly beautiful spot to raise a family, absent of any visible smoke stacks or toxic air releases, began noticing some unexpected birth defects in 1982. Fairchild Semiconductor Corporation, a computer technology producer, found evidence of nearly 50,000 gallons of leaked toxic chemicals underground. The most alarming chemical discovery was that of trichloroethane (TCE), a cancer causing toxin. San Jose residents began raising concern when mothers of the area compared shared miscarriage experiences and birth defects among their young children. Nearly 50 days after the discovery of the leak by the state health department, a local newspaper released the disclosed information to residents. Larraine Ross, a distressed mother of a daughter with a serious heart defect took action and united 15 neighbors together to sue the Fairchild Corporation, along with the area’s main water supplier, Great Oak Water. The case concluded in 1986 with a multimillion dollar success settlement in support of nearly 530 affected residents in the Los Paseos area.
Despite decades of environmental activism from communities banning together to fight for clean air and water, there are still groups today fighting for a voice and an action for change. North Birmingham, Alabama has been a booming home to the steel and coal industry for decades. The facilities in the area have contributed chemical pollutants including arsenic, lead and benzo(a)pyrene. After constant investigation, in 2011 the EPA recommended a “time-critical removal action” for the 35th Avenue Superfund Site. The EPA determined a necessary clean up for the northern region of the community, yet years passed with no movement. In July of 2017 it was revealed why there was such a lag in government support for clean up. Alabama Representative Oliver Robinson was convicted for bribery by Drummond Company, a large contributor to the pollution in the region. Rep. Robinson took the bribes in an effort to keep the EPA from expanding the Superfund site and for keeping the area off of the NPL list for receiving advanced community pollution remediation. After the trial and years of battling pollution contributing facilities, community residents are still fighting for significant change and relocation away from the reach of cancerous toxins.
August 2, 1978 marked the beginning of a movement for communities to unite together for the shared vision of a clean backyard. The success of evacuation for Love Canal residents stands as an inspiration and model that through organization and persistence environmental change is possible. There are many cases throughout the last few decades that show the success cities and towns have had in community remediation. However, even today the battle still rages on as cities and towns across the country fight for the same right to clean air and water.
Exposure to the pesticide chlorpyrifos has been linked to brain damage in infants and children. California banned it earlier this year, and last August a federal court ordered EPA to ban the chemical. EPA announced last week that it would not ban the pesticide, citing insufficient data. <Read more>
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As the Huffington Post Reports, according to recent data from the EPA, the amount of unhealthy air days in major cities across the US have increased in the past two years, even though polluting air emissions have decreased overall. <Read more>
A mining company involved in the Bonita Peak Mining District Site by the Animas River in Colorado is rejecting EPA’s order to participate in the clean up of the area. The Superfund Site in question is made up of several inactive mines that have been leaching waste into the nearby Animas River. The site was first established in 2015, when EPA inadvertently triggered a spill from Gold King mine, contaminating river systems with 3 million gallons of toxic wastewater.
Sunnyside Gold Corp, the company EPA initially ordered to conduct a groundwater assessment of the area, is now refusing to take action to clean up the area, saying that they are not responsible for the polluting spills. EPA said they would review the company’s leader before taking further action. <Read more>
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EPA Administrator Andrew Wheeler announced last Friday that the EPA is strengthening standards for lead dust, especially in schools and work places, throughout the county. Their updates include reducing the amount of dust considered to be a hazard in an attempt to better reflect the amount of lead that can impact children. These new standards focus on lead dust on floors and on windowsills. <Read more>
This is the question that journalist Jim Daley raised recently in an article published in Scientific American. According to the article, the U.S. Environmental Protection Agency (EPA) is substantially changing the program that evaluates the toxicity of chemicals by shifting staff and program emphasis from the Integrated Risk Information System (IRIS) to duties related to implementation of the Toxic Substances Control Act (TSCA). Daley writes that “Former EPA officials contend that the shake-up takes chemical assessments out of the hands of career scientists, potentially to the detriment of public health.”
As evidence of this shift, Daley writes that that the agency has reduced the number of its ongoing chemical toxicity assessments from twenty to three.
The IRIS Program began in 1985 to support EPA’s mission to protect human health and the environment by identifying and characterizing the health hazards of chemicals found in the environment. The IRIS program has become the most respected scientific program in the agency. Its health assessments are the backbone of EPA risk analysis work and is the preferred source of toxicity information used by EPA to determine public health risks. It is also an important source of toxicity information used by state and local health agencies, other federal agencies, and international health organizations.
The TSCA program on the other has a much narrower focus which is primarily on reporting, record-keeping and testing requirements, and restrictions relating to chemical substances and/or mixtures, according to EPA’s website. Certain substances are not covered by TSCA including food, drugs, cosmetics and pesticides. While the 2016 amendment to TSCA greatly improved this regulation, it did not address its narrow focus. This shift began with the leadership of Andrew Wheeler who took over for a beleaguered Scott Pruitt as administrator of EPA in July 2018.
One EPA official who declined to be identified was quoted in the Daley article saying that IRIS and TSCA are “very different” in their approaches to evaluating the public health risks posed by exposure to chemicals. “One could make the argument that this is political interference, in that high-level people are saying which methodology we should be using to assess the safety of a chemical. “And the policy’s pretty clear that they’re not supposed to do that.”
Bernard Goldstein, Professor Emeritus at the University of Pittsburgh School of Public Health, who served as EPA Assistant Administrator of the Office of Research and Development (ORD) from 1983 to 1985, summed it up this way in the Daley article, “I really see this as part of a restructuring of EPA in such a way that science will have very little to do with what EPA is basing its regulation on, and that we will end up with much weaker regulations in terms of protecting public health. “It’s troubling, in large part because it’s very consistent with an overall approach – a very astute approach – to take out the inconvenient facts.” Also cited in the same article was a comment by Thomas Burke from the Johns Hopkins Bloomberg School of Public Health, a former EPA lead scientist adviser and Deputy Administrator of ORD from 2015 to 2017, “’any reduction’ of the number of IRIS chemical assessments ‘is a loss for public health and, unfortunately, puts populations who are exposed at risk.’”
Read the full article here.
As WWMT News reports, an EPA advisory group will hold three community meetings for the Allied Paper, Portage Creek, Kalamazoo River Superfund Site. These meetings are meant to serve as town halls for the community to discuss the status as the clean up, as well as the role of Michigan and Natural Resource Trustees in the clean up. Each meeting will discuss a different aspect of the Superfund Site clean up. <Read more>
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Portage Creek Superfund site on the Kalamazoo River Jeremy M Wintworth, Creative Commons
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While drinking water in the United States is some of the safest in the world, that doesn’t mean that everyone should be drinking the water that comes out of their tap. Water scientist Joan Rose reports in the Great Lakes Echo that 43 states have toxic fluoride contamination in their water (PFAS), and many agricultural communities face arsenic and nitrate contamination from agricultural runoff.
Every single person on the planet needs to drink water in order to survive, and for many families, buying bottled water becomes an unfair financial burden. Under the Safe Water Drinking Act (SDWA), the EPA has been able to execute a water quality management program that keeps most of our tap water safe to drink. However, some communities are slipping through the cracks and many citizens are unwittingly drinking contaminated water. <Read more>[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]