Bisphenol A, found in everything from baby bottles to the lining of tin cans, could constitute a danger to human life and health, Health Canada reported last week.
Even the dental industry has cause for concern:"Just when they thought they could breathe easy after years of controversy concerning mercury-based fillings, dentists are finding themselves at the centre of a new debate over the safety of the alternatives," writes Carly Weeks in The other place bisphenol A lurks: our teeth .
"An increasing number of dentists are using sealants and fillings that may expose patients to bisphenol A, a chemical the federal government said last week is potentially dangerous and will be banned from use in plastic baby bottles."
Some studies have found detectable levels of BPA in the saliva of patients after they received sealants or fillings, but experts are divided as to whether this low exposure constitutes a health risk."
The chemical, which studies show acts like the female hormone estrogen, has been linked to early puberty in girls, breast and prostate cancer, and attention deficit and hyperactivity disorderto cancer and infertility in animals.
Dr. Kapil Khatter's answers to select reader questions on BPA are now available and appear at the bottom of this page.
Dr. Khatter is a family physician and environment and health expert who leads chemical-related policy work at Environmental Defence . Dr. Khatter has a master's degree in environmental studies and has sat on a number of working groups tasked with providing expert advice to Health Canada and Environment Canada.
For the past couple of years, Dr. Khatter has been working on the review of Canada's national pollution law, the Canadian Environmental Protection Act, and on the federal government's Chemicals Management Plan.
Dr. Khatter is also a board member of Health Care Without Harm and the President of the Canadian Association of Physicians for the Environment. He has scientific and policy expertise related to the environment and health, with a unique perspective that comes from being a physician.
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Pearl Sefarian, London: Will you please give us some guidance regarding food in tins? Should we throw out what we now have in our cupboards? Are some foods in tins safer than others? I am thinking about acidic foods like tomatoes and tomato sauce, and also about tinned fish, and tinned lentils. What about peanut butter and vinegar which now routinely come in plastic jars with a triangle on the bottom? Is a triangle with the number 7 in it more dangerous than a triangle with the number 2 in it? thank you
Kapil Khatter: Hello Pearl, There is little information about which food cans are safest. The federal government's recent draft assessment found a broad range of bisphenol A levels in various canned food. The highest levels were actually found in canned vegetables and soups, but the number of cans tested has been too small for that to be a reliable guide. It may have as much to do with how the lining is made as with what food is stored inside. A few companies have started to use cans without bisphenol A and hopefully the number will increase.
Plastics with number 2 recycling symbols so far appear to be of less concern. But there is a lack of publicly available information on their potential risks. Polycarbonate food containers labeled with a number 7 (though not all number 7s), and PVC containers with number 3s are the ones that can leach bisphenol A. Laboratory research has raised serious concerns about the safety of the chemical, so avoiding bisphenol A plastics makes sense as a priority.
Ken Ohrn, Vancouver: I understand that roughly 2 million tons of BPA are manufactured each year. It is used in a wide range of products, including water pipes. With such wide usage, how could anyone avoid ingesting it?
Kapil Khatter: Hi Ken, You can't avoid ingesting bisphenol right now. Testing has shown that practically everyone is exposed to bisphenol A every day. When you look at the high levels in house dust this is not surprising. That is why a broader government plan to phase out uses of bisphenol A is so important. We should eliminate direct contact from food cans, baby bottles and re-usable water bottles with the chemical right away, but we also need longer-term action to minimize our exposure.
John Dixon, Vancouver: I have a bunch of those sport drink bottles with the nipple-tops which have been great for filling with water for my kids to take in their bags. I have re-used them many times, they've all been through the dishwasher numerous times and some of them have become dull and chalky. My question is: does this (and other potentially harmful chemicals) leach out and then the plastic becomes safe, or do they continue to leach forever? Also, is room-temperature use acceptable (does heat or even cold cause these chemicals to leave the plastic and enter the food?) Sometimes when a bottle of water has been sitting in the hot car or something it gets that plastic-y taste. Is this a good indicator of the presence of the harmful chemicals?
Kapil Khatter: Hi John, Polycarbonate likely never stops leaching bisphenol A as it is a building block of the plastic. PVC bottles (with number 3 recycling symbols) will also continue to leach the chemical. Heat does make these plastics more risky, but it is difficult to assume that room temperature use is safe, especially as bottles become worn.
The "plastic-y taste" is not a reliable sign of bisphenol A leaching. The chemical doesn't appear to have a taste, which has been confusing for those who assumed that taste-free hard plastic bottles were safe (or at least safer).
Suzette Fram, Maple Ridge: Is low exposure a real risk to most people? Should I discard my PC water bottle and should I stop eating canned foods? What advice do you have for most of us whose exposure is fairly low?
Kapil Khatter: Hi Suzette, It is difficult to be sure how much of a risk low exposure is. There is significant concern given animal studies have shown worrisome effects at the kinds of doses we are being exposed to. The evidence is growing that hormonally-related effects can occur with small doses because of the sensitivity of receptors.
But does that mean people are being harmed by bisphenol A? We can't say for sure. I would (and did) discard my polycarbonate water bottle, and wouldn't use a PVC one either. Stainless steel bottles work well. It is also good to minimize the amount of canned food you eat, to reduce your bisphenol A exposure, and because fresh food is healthier anyway.
Edmund S, Winnipeg: We are confused about what plastics are safe. I've heard that Number '7' are the 'unsafe' ones, but what about other 'numbers... 6, 5, 4 etc' ? Are these safe? We would really like clarification on this! Thank you so much!
Kapil Khatter: Hi Edmund, We can't say for sure that other plastics are safe. Very little testing has been done on the leaching from plastics and whether it is harmful. I'd say that avoiding the ones we're most worried about would be a good priority. Polycarbonate (number 7 — PC) and PVC (number 3) plastics have the most worrisome profiles. Another "better safe than sorry" approach is to never heat food or drink in any plastic containers. Heat generally increases leaching from plastics.
NS Guy, Halifax: Are there any specific identifying marks that will indicate a container includes Bisphenol A in its composition? Do all containers marked 'Nalgene' contain this substance? Many thanks.
Kapil Khatter: Hello Guy, When polycarbonate plastic products (made from bisphenol A) have recycling symbols they will have a number 7 and possibly the letters "PC" written beside. Only with the "PC" labeling can you be sure it is polycarbonate. Not all Nalgene brand water bottles are made from polycarbonate, only the hard, nearly unbreakable ones. Nalgene has recently announced though that they are changing their bottles and switching to another plastic.
Recent evidence suggests that bisphenol A added to PVC plastic actually leaches more than polycarbonate does. So containers marked with number 3 recycling symbols can also add bisphenol A to your food or drink.
Kristina Parusel, Vancouver: I've read that Bisphenol A is in the non-stick coating on cooking pans (Teflon). Is it in all non-stick coatings, only some, and has it been removed altogether for new pans? Thanks! Kristina
Kapil Khatter: Hello Kristina, I haven't seen any evidence that bisphenol A is used in cookware coatings. You are probably thinking of the perfluorinated chemicals - stain repellants and non-stick chemicals like PFOA and PFOS. These chemicals are of concern as well. Not only do they cause harm in animal studies, they are very persistent and build up in our bodies. I believe that companies are trying to reformulate pans so that less PFOA is released.
Francois Hunter, Canada: Hello Doctor; It would seem that BPA's are lurking everywhere... I had never paid attention before, and was a bit concerned yesterday when I opened the door to our freezer and saw, etched in the plastic of the door, a big triangle with the number '7' in the middle. We store our toddler's food in the freezer... Should we be concerned and get a new refrigerator/freezer ?
Kapil Khatter: Hi Francois, I don't think the plastic in your refrigerator door is going to directly contaminate the food you store. The problem with bisphenol A, as with many other chemicals used to make household products, is that they end up in our indoor air and our house dust. In the case of bisphenol A, the widespread use of the chemical has contaminated house dust. I doubt it is worth getting a new appliance at this point, but limiting the amount of PVC and polycarbonate plastic you buy will help to reduce your overall exposure.
Todd St. Jean, Canada: Our twins will be 3 years old this summer and when they used baby bottles (Avent) containing BPA Health Canada said there was no danger to Canadian families. Now Health Canada considers BPA a danger to human life and health. After being exposed to BPA for 12 to 15 months is the health of our twins in danger?
Kapil Khatter: Hello Todd, It is hard to know how harmful the twins' bisphenol A exposure has been. Remember that bisphenol A exposure poses a risk to health, but it is not a given that they have been harmed.
We really don't know how much bisphenol A contributes to the kinds of effects seen in animals. We are exposed all the time to things that increase our risk of illness: second-hand smoke, pesticide residues, mercury-laden fish. The best we can do as individuals and as a society is to limit those exposures in the future.
Corey Jones, Toronto: Dr. Khatter, From what I've read, I understand that for decades, the allowable level of lead in drinking water has been 10 parts per billion (ppb), and lead is an undisputed toxin with known harmful effects to children and adults alike. We don't seem to be in an uproar about that. Can you explain why levels of 6-8 ppb of bisphenol-A leaching from polycarbonates in conditions optimized for leaching (e.g. heating to 80C) should be such cause for such panic?
Kapil Khatter: Hello Corey, We should be in an uproar about lead. New evidence suggests that even lead exposure below 10 parts per billion (ppb) can be harmful to developing children, affecting intelligence and possible contributing to learning disabilities and attention deficit disorder. Unfortunately, I think the progress we've made getting lead out of gasoline and paint has made us complacent. We really don't know what negative impacts lead in drinking water, consumer products and old house paint are having.
Bisphenol A is important because, like lead, there is evidence of harmful effects at really low levels of exposure, at least in animal studies. Bisphenol A is one of the more widely used human-made chemicals and its use is projected to increase. If it takes an uproar to change that trend, then I think an uproar is what we need.
