While skimming through our morning news, we came across a story on the internet about a chemical known to cause cancer found in one or more sunscreens. Interesting, we thought, do we not use sunscreens to prevent cancer? Once again, the quote, often attributed to Mark Twain, came to mind, along the lines of if you want to stay sane one should give up reading. But against this better judgment we continued.
The chemical was benzene and we both knew it to be associated with blood cancers in people. So that part of the story was correct. But rather than panic, and stop using our sunscreen, we looked for information on how much benzene was present. After all, if we were using sunscreen to keep from getting cancer, then we needed to compare this benefit to the risk of cancer from benzene, and for that we needed to know how much benzene was in the sunscreen. This benefit-risk comparison is not unlike what many of us do every day (driving a car versus walking to the store). We kept in mind that the potential harm from any chemical, referred to as its hazard, only occurs IF the amount of exposure is high enough, and often enough. Most chemicals, like the one described in our morning news, can be made to sound very scary to all of us. Carcinogen is one of the hazards many fear the most, us included, and using it in a headline is guaranteed to get people’s attention, Mark Twain’s alleged statement not withstanding.
So,what about the level of benzene in our sunscreens? Based on the reports of the levels of benzene that we’ve seen, the risk of cancer appears to be extremely low and well within the levels of risk that are found to be acceptable by regulatory agencies around the world. These estimated risks are extremely small and may even be zero. Moreover, the US FDA (Food and Drug Administration) used a science-based process to determine that the given amount of benzene would cause little to no harm. However, do we believe that the FDA should do nothing about the potential sources of benzene in sunscreen? Not at all. Benzene is a contaminant resulting from making the sunscreen and serves no functional purpose. Its presence in sunscreen is causing fear from use of a product that has a clear health benefit: PREVENTING SKIN CANCER FROM TOO MUCH SUN EXPOSURE. Yet another classic example of why we need a risk assessment. Bottom line – the benzene level in sunscreen is extremely low and within the acceptable levels of already very low risk; the sunscreen, used correctly, helps prevent skin cancer. You make the choice. Us? We’ll enjoy the rays and slather on the sunscreen.
By Michael Dourson and Jay Gooch. Dr. Gooch is a toxicologist retired from Proctor and Gamble in Cincinnati, Ohio and Vice President of the Toxicology Education Foundation.
Chemicals by Land, by Sea, and in our Bodies?
September 22, 2022
It may come as a surprise to many of us, but several chemicals of industrial use are also made on a routine basis inside our bodies, of course in a much smaller amount. For example, ethylene oxide is used as a disinfectant to kill bacteria and virus on surfaces of hospitals. It has the added feature of being a dry gas, so it can be used to sterilize certain medical equipment, such as blood transfusion tubes, that are otherwise difficult to keep free of pathogens (I have written about this chemical before as shown here). Another chemical of huge industrial use is formaldehyde. Yes…that same chemical that was used to preserve the frog specimens that many of us studied in high school/college biology classes. Turns out that formaldehyde is extremely useful in making a number of other important chemicals, and yes our bodies make a small amount of it every day in our normal metabolism.
Aren’t these chemicals toxic? Of course they are! All chemicals are toxic AT SOME LEVEL. Ethylene oxide and formaldehyde cause tumors at high concentrations in experimental animals, and there is some evidence that they cause tumors in humans. However, levels causing these tumors are well above those that are bodies make daily, and industries making or using these chemicals protect their workers by establishing thresholds for safety, and include protective equipment.
Can the public be exposed to levels of ethylene oxide or formaldehyde that might cause us harm? Generally no. The levels of either of these chemicals in the environment more or less matches levels found in each of our bodies, so getting exposure to levels that can cause us harm is very unlikely. However, the U.S. Environmental Protection Agency has recently reaffirmed a previously established safe level of ethylene oxide and proposed a safe level of formaldehyde that are WELL BELOW what our bodies make every day. These levels are overly safe, and as a result call into question the process by which our EPA developed these estimates. For example, the overall impression of EPA’s current draft is that formaldehyde is toxic at levels below what is often found indoors or in outdoor air. Perhaps not surprisingly, many scientists disagree with EPA.
In fact, it is difficult for many of us to understand how EPA can propose safe levels for chemicals that are lower than levels that occur naturally or are produced in our bodies every day. It certainly is not because they do not have the good scientists. Dr. Rory Conolly, one of several of EPA’s former scientists who won the Lehman award from the Society of Toxicology (an award sometimes referred to as the Nobel prize for risk assessment), has published extensively on formaldehyde and is heavily cited in EPA’s text. However, Dr. Conolly disagrees with the current EPA position. EPA should listen.
EPA’s safety level for formaldehyde is still a draft. So what might EPA do to improve it?
First, EPA should focus on formaldehyde’s first toxic effect, which is tissue irritation. Estimating a safety level for other effects does not make sense, since all of these other effects are higher, and by definition the safety level based on irritation will protect against them. Second, EPA should follow its own guidelines for assessment of tumors and develop a safety level based on the way in which formaldehyde causes these tumors at high levels. Dr. Conolly suggests an approach that might work very well. Finally, EPA might consider new information from a recent scientific workshop that showed formaldehyde cannot penetrate the cell at low concentrations. This finding supports the threshold approach adopted by the European Union t al. (2020).
It is certainly confusing that EPA proposes safe levels of these chemical that are below what our bodies makes every day. This makes it harder to trust other EPA assessments, many of which are very good.
Should We Ban This Chemical?
August 3, 2022
While walking through a store the other day, I came across a “toxic” chemical for sale. From previous reading, I knew that it was responsible for a number of adverse events, such as death due to accidental inhalation, severe tissue damage after prolonged exposure to its solid form but serious burns from its gaseous form, and a number of unpleasant though not typically life-threatening side-effects from excessive ingestion. I also knew that this chemical is a major component of acid rain, contributes to soil erosion, leads to corrosion and oxidation of many metals, contaminates electrical systems which often causes short-circuits, and decreases effectiveness of automobile brakes. It has also been found in biopsies of pre-cancerous tumors and lesions.
The media will often talk about chemicals in a way that makes them sound scary. And indeed some chemicals are quite toxic in small amounts and we should all be careful when we use chemicals around the house for cleaning or pest control, making sure that we follow the label and keep these products out of reach of our children. But a description of a chemical’s toxic effects, without an understanding the dose to which one might be exposed, is not helpful. A liter of botulinum toxin, the most toxic chemical known to humans, will kill most of the humans on planet Earth, yet we used this same chemical to treat wrinkles and migraine headaches in incredibly tiny doses. As toxicologists are fond of saying, it is the dose that makes the poison. Reciting a scary list of possible effects from a chemical exposure, without indicating what the exposure might be, is not good science or journalism.
So how might one go about and determine a level of chemical exposure? A good rule of thumb here is to take the smallest sugar granule you can see from a sugar packet. It weighs about 50 micro-grams. If you put this sugar grain into a liter of water it becomes about 50 parts per billion (or ppb). This is not a lot, but gives you a sense of a chemical level. Many chemicals are safe at this level. For a listing of safe levels of various chemicals see: https://iter.tera.org.
It is impossible to live in a world without chemicals. So be informed, and make sure you drink plenty of DHMO!
Follow the Science?
July 6, 2022
“Follow the Science” is a phrase occasionally heard from our family and friends, and signs found in yards throughout various neighborhoods often state “Science is Real,” followed by “Water is Life.” So what exactly does this mean? Water certainly is an essential to life in our world, yet when we drink too much, water acts as a neurotoxin that can lead to death. So science says water is good but the science of toxicology says it can also be bad. Science really says it is the LEVEL of exposure that makes the difference.
The science of toxicology deals with exposure to levels of chemicals. Remember – LIFE IS CHEMISTRY. We are exposed to tens of thousands of chemicals every day, and most are naturally occurring and some even necessary. In fact, ALL chemicals are toxic at some level – even water, as noted above. So it comes down to the exposure that determines the toxicity, and all chemicals have a level with little or no toxicity.
Mercury in fish, for example, is naturally occurring. All fish in the world have some level of mercury (and of course may have more as a result of environmental pollution). Eating fish is very good for you; therefore, dietary guidelines are set to limit our exposure to mercury to below its safe level. [Dietary guidelines provide advice on what to eat and drink to meet nutrient needs, promote health, and prevent disease]. Lead is another example of a naturally occurring chemical. However, we all know or have heard of the medical problems associated with too much lead from contamination. Here again, the exposure makes the difference. Ever heard of formaldehyde? If you ever dissected a frog in biology class, you most likely have smelled it. Guess what? Your body makes it every day. Yep, another naturally occurring chemical that is toxic at high levels, but which also has a safe level.
So when you hear someone claiming a particular chemical is toxic, ask yourself two questions. First, who is making the statement? A TV host, a news reporter, a lawyer, a physician, or a scientist with expertise in toxicology? Take time to consider the background of the person making the statement. Just as you wouldn’t go to a lawyer for advice about your swollen ankle, why would you make a judgment on a chemical without getting the facts from a toxicologist?
Second, find out “how much is the exposure?” A good rule of thumb here is to take a sugar packet, dump it out on the table, and find the smallest sugar grain you can see. Wet your finger and pick it up. Then put this sugar grain into a liter of water. The sugar grain weighs about 50 micro-grams. When you put this into the liter of water it becomes about 50 parts per billion (or ppb). This is not a lot, but gives you a sense of a chemical level. Many chemicals are safe at this level.
So should we follow the science? Of course! But make sure that the statements made regarding the toxicity of chemicals are from toxicologists, or that reporters sharing such information reference these experts. Otherwise, we are likely to stop eating some of our favorite foods, like lake Erie perch, a healthy part of any diet, because of misinformation. Or we are likely to stop using very helpful products, like lead batteries that start our cars, because of misguided fear? It is impossible to live in a world without chemicals. So be informed. That is following the science.
KEEPIN' IT CLEAN
June 7, 2022
At one or more times in our life we are all likely to end up in a doctor’s office or hospital for a medical procedure. Or we may decide to give blood so that someone else’s life can be improved, or even saved. Often medical staff will use equipment to monitor our symptoms or to take measurements. Sometimes this equipment is used only once, like gloves, but often it is reused, such as stethoscopes or scalpels.
Banning Pesticides: Is This in the Public's Best Interest?
May 2, 2022
Farmers routinely use pesticides, whether organic or not, to control insects and weeds on our crops. This often results in pesticide exposures to our farmers, and occasionally to us when a little bit of pesticide remains on the crops after harvest. However, when the pesticide is used according to its instructions, the safety of our farmers and ourselves is assured due to the extensive testing by industry (millions of dollars in studies) and review by government scientists, many of them who are doctorate-level and board-certified toxicologists. We, the public, also get the benefit of increased crop yields, which usually translates into lower food prices and the benefit of product availability.
So is banning pesticides in the public’s best interest? The answer is an emphatic yes when the science indicates that exposures are not safe. But does good science always get used in making decisions? Fortunately the answer is nearly always yes, with some exceptions. For example, EPA recently banned all uses of the pesticide dursban (also know as chlorpyrifos). This was despite the fact that EPA scientists determined that levels of dursban were safe on many crops when used according to its directions, even for sensitive humans and children. This ban prompted a lawsuit by a number of food producers for soybeans, sugarbeets and cherries asking EPA to follow the findings of its own scientists. Why? Well the State of Michigan grows a majority of U.S. tart cherries and a good portion of U.S. sweet cherries, and dursban is considered to be critical to the Michigan cherry industry as there are no alternative pesticides that effectively control trunk borers. Those of us who have tried to grow apples, pears or peaches without the aid of spaying our trees---and ending up with little to no edible fruit---can certainly relate. So to the Michigan cherry famers, EPA’s ban might be Cherry-O…
But why would EPA ban all uses of dursban when its own scientists said many of its uses were safe? The answer, as are many, is complex. But one reason is not the lack of qualified staff. EPA has highly credentialed staff, more so than many other organizations. One of the reasons might have to do with environmental activists who want to ban all pesticides that cause toxicity to the nervous system of insects, and also in humans that get exposed from improper use. If dursban exposures were actually causing harmful effects at EPA’s determined safe levels, this would be entirely appropriate. But this is likely not the case as one recent scientific publication suggests.
So again, should we worry about pesticides to which we are daily exposed? Well, it all depends on how much of the exposure one gets, as previously described. Too much of any one thing is likely not to be good for us. This includes pesticides, like dursban, but also other natural, organic and conventional pesticides. However, government agencies work very hard to keep us safe. Follow the labels on the various chemical products to stay safe, use products in moderation, and of course follow the science.
The Chemicals All Around Us?
April 2, 2022
We often hear folks talk about wanting to live a chemical-free life, or at least one associated with only natural chemicals. This talk often centers around the use of pesticides, a type of chemical used for killing pests that otherwise destroy or contaminate our food. For example, some folks rave about food grown organically, erroneous thinking that NO pesticides were used in its production, whereas food grown with conventional pesticides is less healthy. But is there really a difference between organic and conventional pesticides? Is it really possible to live without chemicals?
The short answer to the last question is an emphatic no. Life is chemistry. We are all exposed to tens of thousands of chemicals every day, the vast majority of them naturally occurring. A cup of coffee, for example, has about 1000 chemicals, the primary one being dihydrogen monoxide (H2O or water). A potato likely has just as many chemicals, including the naturally occurring pesticide solanine. This latter pesticide is the reason that eating potato leaves or the green parts of potatoes will make many people sick. Not surprisingly, the part of the potato that is not green, the part that most of us eat, also includes the natural pesticide solanine, but at a level that is lower than a toxic level. So we do not need to worry about eating potatoes even though they contain a lot of chemicals, including its natural pesticide. In general, plants routinely make their own pesticides from naturally occurring chemicals to protect themselves from pests or to eliminate competition. Anyone trying in vain to grow tomatoes underneath or near walnut trees will know this to be true. The chemical juglone, a naturally occurring pesticide, is highly destructive to sensitive plants, like tomatoes.
So is it better to eat only organic produce? Not at all. Much of the information about pesticides one can find from websites is one-sided, describing hypothetical dangers of low levels of synthetic pesticides, and showcasing organic farming as a pesticide-free alternative, which it is not. In fact, organic farming often results in more insect damage, which in turn causes the crop to make more of its naturally occurring pesticide. It is important to remember that each pesticide, whether organic or conventional, is intended to kill pests. The only overall difference in organic and conventional pesticides is that organic pesticides generally come from natural sources.
So should we worry about chemicals to which we are daily exposed? Well, it all depends on how much of the exposure one gets, as previously described. We can all be exposed to some chemicals in large amounts, like water, and still be safe, or mixtures of chemicals that make up most of our foods. But we all know that too much of any one thing is likely not to be good for us. This includes natural and conventional pesticides as well as many household products. Government agencies work very hard to keep us all safe. Following the labels on the various chemical products we use is a good start to a safer life.
PFOA: The Forever Chemical?
March 3, 2022
You probably have heard a lot about the chemical PFOA (perfluorooctanoate), sometimes called the “forever” chemical. PFOA is a simple 8-carbon molecule that has fluorine atoms attached rather than hydrogen atoms. As a result PFOA resembles several fats found naturally in our bodies, but it does not break down to any significant extent. Although PFOA does not occur in nature, it is a very useful tool for firefighters in putting out electrical and oil fires that cannot otherwise be doused with water. And because it is chemically stable it has been used in a variety of household products, such as carpets and food wrapping. Due to its extensive use in so many areas of our lives, very low concentrations are found in our bodies, our houses and our environment. In a few places, these levels may be harmful.
This chemical has been studied A LOT, and for all the study, a big problem has emerged: There are large differences in government opinions as to what the safe level of PFOA actually is according to recent international meeting. Sometimes these differences are as much as 750-fold. These differences are principally due to two issues. First, the determination of PFOA’s safe dose depends, in part, on establishing its first toxic effect in experimental animals, such as a change in liver enzymes, and government agencies, even within the US disagree. Second, the time it takes for PFOA to leave our bodies is generally much longer than that measured in experimental animals. This longer half-life lowers PFOA’s safe dose estimate for us.
This is a prime example of what environmental risk assessment is all about. PFOA is an important and very useful chemical, particularly for firefighters, but as with any chemical, too much may be harmful. Do we eliminate the products and its use in electrical and oil fires, or try to determine, collectively, a safe level for our environment? Trying to determine a more uniform safe level seems to be the better course. However, this is a difficult task, and so it would make sense that governments and other organizations work together to accomplish this goal.
Recently, an international scientific collaboration has resulted in a consensus position on the time required for half of the PFOA to leave our bodies, and it is not nearly as long as other groups think. This is good news, but like any science, this consensus needs to undergo peer review during submission for publication later this month. In the meantime, this consensus may alleviate part of the differences in opinion among government groups and lead to more uniform estimates of PFOA’s safe dose. Additional collaborative work should also be started in other areas of scientific differences.
RoundupTM: Are we safe from its exposure?
February 6, 2022
All of us have likely seen the advertisements on television offering legal counsel for individuals who might have had exposure to the herbicide RoundupTM and have certain cancers. These ads are based on a court ruling in California, which was based in part on publications that purport to show links between cancers and hormone-related effects. Others have opined that the U.S. Environmental Protection Agency (EPA) is not doing its job in protecting the US public from the dangers of glyphosate, the active ingredient of this herbicide. So natural questions for any of us to ask might be:
The short answer to either question is an emphatic NO. EPA and health agencies around the world have reviewed hundreds of experimental animal and human studies on glyphosate and come to a near unanimous conclusion:
For example, the U.S. Department of Agriculture (USDA) released a 2016 report that found no pesticide residue levels high enough to pose any human health risks, even for infants. Specifically, the USDA tested for pesticides in 10,619 samples of food. Pesticide residue levels were found to be at or below tolerance levels set by the EPA in all but 0.4% of the samples. Importantly, tolerances would have to be exceeded routinely for nearly a lifetime for any possible health effects in the most sensitive members of our public---a very remote possibility.
The one exception to the otherwise unanimous conclusion on the safety of RoundupTM by US and other health organizations was that drawn by the International Agency for Research on Cancer (IARC) in France. Importantly, judgments by this group are not peer reviewed. Other items included in IARC classifications are eating red meat, exposure to emissions from high frying temperatures, and working as a hair-dresser or barber.
So why is IARC’s judgment different than all other organizations?
IARC classifications are based primarily on a chemical’s “hazard” potential, and do not generally consider the dose at which effect can occur. This IARC approach differs greatly from the “real world” conclusions drawn by multiple international regulatory agencies that RoundupTM exposure at current levels does not cause cancer in humans. Moreover, the IARC approach ignores one of the key principles of toxicology---that all chemicals are toxic at some dose, yes, even water. So making statements of health risk without accounting for the dose causing the health effect is not good toxicology, nor good medicine.
For additional reading on the supposed risks from RoundupTM and for links to stories about its well-known benefits, especially to the farmers in our area and around the world, please see well-balanced essays here and here.
Reader Question: Flame Resistant Pajamas?
January 3, 2022
Reader Submitted Question: I recently bought polyester flame resistant pajamas because my daughter is in an in-between size stage. The doctor’s office said she either needs to wear the flame resistant or tight fitting cotton non-flame resistant. The issue is that there isn’t a current cotton size that would comfortably be snug on her. What would you recommend?
The "Dirt" on the Safety of Detergent Packets:
December 9, 2021
As parents and grandparents of young children, we should always make ourselves aware of new potential hazards that we bring into our homes. Some of us may even have called the local poison control center with various concerns over some items (1-800-222-1222).
Several studies have been published that compared child exposures to laundry and dishwashing soaps and to packets of either one. It has been shown that twice as many children are exposed to these soap packets than the regular laundry and dishwasher soaps and the children exposed to the soap packets experienced more severe health effects. The data used for these studies were extracted in part from the National Poison Data System (NPDS) for reported exposures for children under 6 years old from 2013 through 2014.
Please make sure these dishwasher and laundry detergents, and all of your cleaning supplies, such as floor cleaners, disinfectants, and hand sanitizers, are stored in a secure place out of the reach children.
For Additional information please see:
Understanding Asthma – and its causes:
November 5, 2021
Since 2001, the total number of people with asthma has increased from 7% to 8% in the U.S, with children being diagnosed with at slightly higher levels. As a parent, this is a huge and worrisome number.
So what is asthma?
Asthma affects the respiratory system, causing the airways to become narrow, which limits the amount of air we can breathe into our lungs. Sometimes this narrowing makes our cells produce more mucus, which further limits airflow. A person with asthma will have shortness of breath, and perhaps wheeze, cough, and have chest tightness. Sometimes asthma ends on its own, but often it requires treatment with medication through an inhaler to open the airways. Some asthma attacks can be severe and require emergency treatment. Although asthma appears to be a lifelong disease, it can be easily controlled by medications that prevent an attack or reduce symptoms, or by avoiding by things that may trigger an attack. So what causes asthma?
Asthma is linked to a number of common household allergens and irritants, like pet fur and dander, dust, cigarette smoke, mold, and pollen. A number of other common pollutants found in the air can also cause asthma, such as ozone and car exhaust. Respiratory infections as an infant or in early childhood can also cause asthma. Asthma may also be genetic. Well, what about hairspray and cleaning products?
Some research says that cleaning products may cause wheezing in young children. Another study even suggests that exposure before birth, or during pregnancy, may increase your kids’ risk of wheezing. Unfortunately, most studies cannot link one individual chemical or product to the increase in wheezing or asthma-like symptoms. And although we can rely on animal research to get this kind of information, animals are frequently exposed to extremely high concentrations, which do not represent everyday human exposures. In contrast, regular cleaning reduces the presence of known allergens and irritants mentioned above, and has been shown to reduce allergy and asthma symptoms. There are many sites on the internet that provide lists of chemicals and other items that supposedly cause asthma, but not all of these sites are reliable. If you are interested in seeing if a particular chemical might cause asthma, we recommend visiting the website of the Association of Occupational and Environmental Clinics that has a searchable database (http://www.aoecdata.org/ExpCodeLookup.aspx). A final note on causation, more recent research suggests that being TOO clean may actually increase your child’s risk of developing asthma. Huh? In fact, the modern world has greatly increased standards of hygiene and sanitation over the years, thereby reducing the rates of disease and increasing overall health.
That’s great, right? Maybe not!
This research, referred to as the “Hygiene Hypothesis,” suggests that because our better sanitation and hygiene has decreased the number of infections that our kids get, this hasactually caused an increase in asthma. Why? Because infections allow our immune systems to develop properly, and thus any reduction in childhood infections may actually make kids MORE at risk for allergy and asthma. Not surprisingly, the use of antibiotics in early childhood is also linked to childhood asthma and allergy problems, and maybe for the same reasons. We are not allowing our kids to recover from their own infections by themselves, which would strengthen their immune systems.
So are kids getting asthma because of too many allergens or household chemicals? Or because they are not getting exposed to enough dirt? There is no real answer yet. But in the meantime, the US EPA suggests that improving household air quality can drastically reduce asthma and allergy symptoms (http://www.epa.gov/iaq/pubs/careforyourair.html).
October 8, 2021
I have a seven month old and a trying to find information if items made from or with polyurethane are safe. My initial concern came after purchasing a piece of small furniture for the nursery where the odor was unbearable. The product was made from polyurethane foam and covered in polyester. I researched and found different results indicating it was or was not safe to expose your child to these products because of the smell and the toxic chemicals the products are made with. Is this true? If I can’t smell the chemical, is it still dangerous? Also, are there different types of polyurethane? I would like as much information on the subject as possible please, as I have found many products do have polyurethane in them.
Thanks so much for your question. It is important for parents to be vigilant regarding their children’s health. Usually, if you can smell one or more chemicals coming from any consumer product, this indicates that the product is releasing a small amount of chemicals that are volatile, that is they are easy emitted to air. Usually, a stronger smell is associated with a higher level of these chemicals in air. At some level, you or your child might experience irritation or minor health effects, such as coughing. However, sometimes the levels are high enough that more severe health effects occur, such as trouble breathing, headaches or dizziness. If you think that you have experienced severe health effects, please have everyone leave the room immediately and contact your local poison control center at (1-800-222-1222).
If the smell is bothersome, but not causing any health effects, then placing the product in a well-ventilated room or garage for several days to a week is your best course of action. After some time, these volatile chemicals should go away. The remaining chemicals, such as polyurethane, should be chemically stable and not a health risk. If the smell persists after a week or so, please contact the retailer or manufacturer and ask for a refund. The release of chemicals from such products after this length of time is not generally normal.
All chemicals are toxic at some level, yes even water! All chemicals have safe levels (or virtually safe levels) to which we all can be exposed. Thus, all products contain chemicals that are toxic, but unless the product is releasing chemicals over a safe level, you should not need to worry. The U.S. Consumer Products Safety Commission has a website that can be searched to give information on chemical releases from different products. A list of safe chemical levels can be found here. If you want information on chemicals not found in this list, please feel free to contact me again.
Dr. Michael Dourson
Exposure to Chemicals found in Swimming Pools, Hot Tubs and Spas
September 8, 2021
It’s summertime and families will begin to use swimming pools, hot tubs and spas for exercise and leisure activity. Health agencies are typically concerned with the water quality due to microorganisms, aka germs. However, public concerns have been raised regarding potential adverse health effects resulting from exposure to the chemicals that are present in the pool water itself. When considering exposure to these chemicals, it is important to distinguish between exposure to pool treatment chemicals in their undiluted form and exposure to chemicals present in the pool water itself. Chemicals used to treat pool water are typically sold in very concentrated forms as they are intended to be added to large volumes of water. Pool treatment chemicals should be kept in places where children cannot access them as direct exposure can cause breathing problems or may result in burns to eyes and skin. If swallowed, undiluted pool treatment chemicals may be fatal. Always follow the provided instructions for the safe handling and use of pool treatment chemicals.
Lead in Paint & Old Houses – Risks to kids
August 5, 2021
Lead can be found nearly everywhere in the environment, including the air, water, food and soil. Although lead occurs naturally in the earth’s crust, much of our exposure results from industrial activities, such as manufacturing. In addition, lead is used (or was previously used) in a wide variety of products, including those found in and around our homes, such as paint, plumbing materials, gasoline, batteries, and cosmetics. Residential lead-based paint was banned in 1978 by the U.S. Consumer Product Safety Commission. However, it is estimated that over 80% of the homes built before 1978 contain some lead-based paint. Lead-based paint used on toys and furniture was similarly banned in 1978.
Exposure to lead can occur through a variety of pathways. Ingestion of paint flakes and dirt, inhalation and ingestion of dust, and ingestion of contaminated drinking water are common among children as lead tastes sweet. To reduce your children’s exposure to lead, keep them away from contaminated dirt, remove shoes before entering the house, and remove or cover leaded paint. Painting the exterior of your home is one of the best ways to prevent exposure to the lead from the existing paint. Additionally, if your home is more than 70 years old, it likely contains some lead plumbing. Testing your home’s water can show if your water supply contains trace amounts of lead. Lead in drinking water can be greatly reduced by running the water until it is cold or through use of a pour-through pitcher or other home filter system with a lead reduction rating. Labs verify the lead reduction using methods that must be printed on the product packaging.
A more complete essay on this topic can be found at: http://www.kidschemicalsafety.net/Lead-Paint-and-Old-Houses.htm. A video that brings home some of these issues can be found at: https://www.youtube.com/watch?time_continue=5&v=IYpPOpAq8Vs&feature=emb_logo.
July 5, 2021
A true story of chemical risk and benefits:Rats, Cats And Parachutes
Calvin Willhite, Ph.D.
Michael L. Dourson, PhD., DABT, FATS, FSRA
Our story is about a pesticide. People are often worried about pesticides because they are toxic chemicals. Pesticides are toxic so that they can kill things - like bugs. DDT is a bug spray. DDT was outlawed in many countries because once you spray it, DDT breaks down only very slowly in the environment. Since it stays around for a long time, it moves up the food chain and when birds eat bugs sprayed with DDT the chemical causes their egg shells to become thin. The egg shells become so thin that the mothers break the eggs when they sit on them, and the baby birds die. In fact, DDT almost wiped out falcons, hawks, condors and pelicans. After DDT was outlawed, the numbers of birds increased. So at first glance, banning DDT seems like a smart move.
To help the World Health Organization make a decision about DDT, they looked at all the laboratory studies on DDT and then they used a computer to calculate the projected risk of cancer in people who lived in the houses that were sprayed with DDT. This projected risk is not the same as the real risk since this is an estimate based on what scientists measured in mice. Using their best estimate, the World Health Organization found that not more than 3 in 100,000 people would be at risk for cancer after spraying DDT.
Fact Check and Resources
Royal Air Force. 1960. Operations Record Book. Flight of 48th Squadron. March 13. Changi, Singapore. Compiled by Fg.Off.Humphrey
World Health Organization. 2006. WHO gives indoor use of DDT a clean bill of health for controlling malaria.
World Health Organization. 2011. Strengthening malaria control while reducing reliance on DDT. http://www.who.int/ipcs/capacity_building/ddt_statement/en/index.html
World Health Organization. 2011. DDT in indoor residual spraying: human health aspects. Environmental Health Criteria 241. 391 pp. Geneva: WHO
Calvin Willhite, Ph.D.
Michael L. Dourson, PhD., DABT, FATS, FSRA
If you think parachuting cats is a fairy tale, the official Operations Record Book from March 13, 1960 taken down by the crew of a British Royal Air Force (RAF) Beverly transport plane from Singapore describes that it “carried out a unique drop to Bario in the Kelabit Highlands in Sarawak that included over 20 cats to wage war on rats”. The Dayak people of that village thanked the RAF and thanked “all of the cat donors and cat basket makers” and added that “all of the cats are safe.”
June 4, 2021
Hey toxicologists, is organic food safer to eat?
By Michael L. Dourson, PhD., DABT, FATS, FSRA
So how does one sort them out?
So now to the question! Is organic food safer to eat? Or perhaps, are the small levels of pesticides, herbicides and genetic modifications in our food, whether human-made or natural, harmful?
Forman J. and J. Silverstein. 2012. Organic Foods: health and environmental advantages and disadvantages. Pediatrics: 2012-2579. October 22.
Jason J. Hlywka , Gerald R. Stephenson , Mark K. Sears , Rickey Y. Yada. 1994.
May 4, 2021
Too much of a good thing?
We have all likely heard someone say something is “too much of a good thing.” This applies to foods, like ice cream, drinks, like wine, and many kinds of activities, like watching movies. However, this also applies to chemicals to which we are exposed every day, or about which we often read in our daily news.
You might remember the scare a while back about too much arsenic in apple juice. The U.S. Food and Drug Administration analyzed a large number of apple juice samples for arsenic and compared them with their estimate of its safe dose, the level at which no harm was expected. The FDA concluded that the very low levels of naturally occurring arsenic in apply juice were not a public health risk and the juice was safe for consumption. Eventually FDA developed guidance for manufacturers.
These safe levels go by different names, a common one in the US is the reference dose (RfD). But despite different names and slightly different approaches, risk scientists all follow three basic steps:
If you want to learn more about safe levels of chemicals, or how they are developed, many agencies provide a wealth of information. For example:
These are only six examples of many groups that work on behalf of the public to keep us safe.
Who is a toxicologist and how is s/he different than my medical doctor?
Toxicology, the study of poisons, is often thought of as a new discipline. It’s not. It has been around as long as people have been trying out different types of food, and using the occasional poisonous plant, or animal, to dispatch a rival. Toxicology today is more disciplined, with scientists and medical doctors studying various ways the plethora of chemicals to which we are daily exposed to can either be of use, not of use, or downright dangerous. However, even sometimes very dangerous chemicals can otherwise be useful (think botox here, https://www.youtube.com/watch?time_continue=7&v=fFvYUdljVK0&feature=emb_logo). If you want to get a sense of toxicology that is readily understandable, here are 3 sets of facts that can be used around the proverbial office water cooler, or at your next party, should the conversation need a new direction:
So, what do toxicologists do every day? Well, like many occupations, toxicology has a number of sub-disciplines. The one we deal with on a daily basis is human health risk assessment and the related area of regulations. This area is likely to be one in which you are most familiar, since fear of chemicals is prevalent in today’s social media and chemicals are often written up in mainstream news outlets in negative terms. Most of these stories are short on the science and long on the scare, so beware and check the backgrounds of the author and those s/he quotes before you start believing anything.
Toxicologists adept at risk assessment and regulation can be found in government, industry, consulting and, to a much lesser extent, academic and NGO organizations. Sections of scientific organizations are even devoted to risk assessment and regulation. On a daily basis, these toxicologists review studies done on particular chemicals and mixtures to determine safe levels of exposure.
Other areas of toxicology will likely not surprise you. Some toxicologists conduct chemical experiments on animals or cell cultures to determine the level at which effects occur. Some study the structure of a chemical and compare it to chemicals that have similar structures for insights. Some extract natural chemicals from plants and animals looking to make new drugs or other useful chemicals. And all of this and other related work necessitate advanced training in biology, chemistry, physiology and pathology and other disciplines, often ending up with conferral of a masters or doctorate in toxicology.
So, where does your medical doctor fit in? Well, some of the most famous toxicologists are also medical doctors, and so the degree, either an MD or PhD is really not as important in determining whether someone is a toxicologist as the underlying work (https://en.wikipedia.org/wiki/John_Doull_(toxicologist). However, a useful distinction is that a medical doctor is often focused on your health and will get you into a hospital if this is needed. A doctor of toxicology is concerned with preventing ill health from chemical exposure---we try to keep you out of the hospital. Another useful way to look at toxicology is that it is preventive medicine. We are trying to lessen the workload of our medical doctor colleagues by finding ways for you to avoid disease.
So, next time you read a social media post or newspaper article and have a question, send us a note, ask another toxicologist for some help, or go to one of these websites to check out relevant information:
Email firstname.lastname@example.org; email@example.com