Questions & answers about the different kinds of plastic used to make bottles and containers; how to identify different plastic types.
This article describes the types of plastics used in bottles, containers, and tanks, including for water storage, cisterns, and other liquids. We identify possible contaminants that may leach into drinking water from some types of plastic.
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Types of Plastics Used for Bottles, Containers & Tanks
HDPE - High Density Polyethylene - the most widely used material for plastic bottles, HDPE is supplied in FDA-approved food-grade products. It does not withstand temperatures over 160 degF. Also see PLASTIC & FIBERGLASS TANKS, HDPE.
K-SBC - K-Resin SBC plastic containers, a styrene derivative, used for containers but not for oils or solvents.
LDPE - Low Density Polyethylene - similar to HDPE, less rigid, more translucent, more costly, not used for water storage tanks.
Polycarbonate plastic containers made with biphenyl-A (a hormone disruptor)(baby bottles, microwave ovenware, eating utensils)
PET - Polyethylene terephthalate (PETE, PETP, PET-P) is a thermoplastic polymer polyester plastic resin. plastic water tanks may be a health risk to consumers
PP - Polypropylene plastic storage containers, used for foods, tolerates higher temperatures.
PS - Polystyrene plastic storage containers, used with dry products, not for water storage.
PVC - Polyvinyl Chloride plastic bottles or storage tanks, used for bottled oils and soaps, like HDPE it does not withstand high temperatures over 160 degF.
So What Plastic Was Used to Make My Water Bottle, Container, or Water Tank?
How to Use the Plastic Recycling Code to Identify The Type of Plastic Tank or Container
How do you identify what kind of plastic was used to make your water or other storage tank or even your plastic water bottle or food container?
Use this simple guide to plastic recycling codes and look for the recycling indicator or label on your plastic container. Our photo (left) shows an image of the plastic recycling code #7.
#1 plastics - PET / PETE (polyethylene terephthalate) One-time use (do not refill plastic water bottles carrying this recycling mark)
#2 plastics - HDPE (high density polyethylene) (Nalgene Corp. produces HDPE water bottles) - also see PLASTIC & FIBERGLASS TANKS, HDPE
FYI: while BPA-containing plastic containers are expected to carry the #7 recycling label, according to the New York Times (7 Sept. 2010), not all plastics labeled with recycling symbol #7 are in fact BPA-containing.
PET Plastic Water Storage Tank Health, Safety, & Sanitation Advice
Question:
I've been unable to find on-line information about the safety of using
common 1500 gallon plastic water tanks to hold drinking water. Our tank is
shaded, but summers are warm and the water often sits in the tank for weeks,
especially when we are traveling.
Our tank is 20 years old, but according to web sites now selling drinking water tanks, the plastic is polyethylene terephthalate aka PET.
To my knowledge, we haven't had any problems to date with bacteria growing.
I don't taste plastic. We once had a mouse get in and die. Bad smelling water. It cleared up after a few weeks. Probably drank some of it!
Do you have any information or links? - Barbara Stuart
The above-ground water cistern storage tank shown in our photo (above left) is located in San Miguel de Allende, Mexico and is discussed at PASSIVE SOLAR HOME, LOW COST.
Answer:
As Ms. Stuart pointed out, some water storage tanks are made of plastic polyethylene terephthalate aka PET. Polyethylene Terephthalate (PET, PETE or polyester) is commonly used for carbonated beverage and water bottles.
Some water storage tanks have also been constructed of this material.
PET - Polyethylene terephthalate (PETE, PETP, PET-P) is a thermoplastic polymer polyester plastic resin. plastic water tanks may be a health risk to consumers: Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. Proposed mechanisms include leaching of phthalates as well as leaching of antimony. Other authors have published evidence indicating that it is quite unlikely that PET yields endocrine disruptors. - Web search 6/27/2010 Wikipedia. PET
Sorting Through the Confusion of Opinions vs. Studies About Plastic Container Materials, Names, Hazards
Researching the health hazards of plastic containers and asking which plastics are safe can give conflicting and confusing results.
Some sources such as the "green" website Care2.com
assert that PET or PETE polyethylene terephthalate and HDPE high density polyethylene plastic containers are "GOOD: Not known to leach any chemicals that are suspected of causing cancer or disrupting hormones.".
These same sources may tag LDPE, PP, PS as "OK", and tagging PVC or V and PS as "BAD - PVC - According to the National Institutes of Health, di-2-ethylhexyl phthalate (DEHP), commonly found in PVC, is a suspected human carcinogen., and BAD PS - According to the National Institutes of Health, di-2-ethylhexyl phthalate (DEHP), commonly found in PVC, is a suspected human carcinogen." - Web search 06/30/2010 care2.com.
There is also confusion about "polyethylene plastic" bottles and tanks. Don't confuse HDPE plastic (high density polyethylene) with PET - Polyethylene terephthalate (PETE, PETP, PET-P) - see What Plastic Was Used to Make My Water Tank (or water bottle)?
Looking at more expert researchers commenting on PET plastic containers:
But recently researchers have raised serious questions about potential health and environmental concerns for PET or PETE plastics. At Reviewers & References see Sax L 2010, López-Carrillo L, et als 2010, Koike E, 2010, for examples.
In April 2010 Environmental Health Perspectives, a peer-reviewed open access journal published by the National Institute of Environmental Health Sciences, Sax reported that
Polyethylene terephthalate (PET) is widely used to make clear plastic bottles for bottled water and containers for other beverages, condiments, and cosmetic products. There is concern that estrogenic chemicals such as phthalates may leach into the contents from bottles made from PET, although PET is not a phthalate derivative. Sax (p. 445) describes several studies suggesting that water from PET bottles can have estrogenic activity in some bioassays and that phthalates might leach from PET bottles.
The author notes the difficulties in evaluating these studies, especially in cases where there may have been prior contamination of the water or the containers with estrogenic agents or phthalates. Sax suggests that the phthalate content of PET bottles, if present, might vary as a function of the acidity of the product and the temperature and duration of storage. Sax also makes the observation that other nonphthalate chemicals such as antimony, which is used as a catalyst in the polycondensation of PET, might also contribute to the endocrine-disrupting activity of products stored in PET containers. The widespread use of PET plastic for a variety of applications suggests that additional research is needed.
The contents of the PET bottle, and the temperature at which it is stored, both appear to influence the rate and magnitude of leaching. Endocrine disruptors other than phthalates, specifically antimony, may also contribute to the endocrine-disrupting effect of water from PET containers.
Conclusions: More research is needed in order to clarify the mechanisms whereby beverages and condiments in PET containers may be contaminated by endocrine-disrupting chemicals.
If your water storage tank is made from Polyethylene terephthalate (PET), and is exposed to high temperatures such as exposure to direct sun and/or in a hot climate, the health risk may be increased. At References, below, we include citations of several recent articles discussing health risks from Phthalates and PET containers.
Find Your Water Tank Plastic Type from the Manufacturer's Literature, Website, or Sales Support
Watch out: some plastic water storage tank distributors advertise that their tanks comply with some health and sanitation laws while omitting any comment about the type of plastic or possible PET concerns (see below). For example we found plastic water tanks advertised as
Specified IW series water tanks manufactured at Chem-Tainer's Compton, California factory are IAPMO certified to comply with the California Lead Plumbing Law and NSF/ ANSI 61- ANNEX G. This law states that any devices or components sold in the state of California that come in contact with potable water must comply with this law.
But it's easy to check the manufacturer's website or to ask the plastic water tank manufacturer for specifics of the plastics used. For example, Chem-Tainer Industries, a producer of a very wide range of plastic storage tanks indicates that
Chem-Tainer's fresh water tanks are an effective, economical way to store potable (drinking) water for Residential and Commercial applications. Our polyethylene resin complies with U.S. Food and Drug Administration regulation 21CFR 177.1520 (1) 3.1 and 3.2 for storage of potable water. These tanks are designed for water use only.
BPA - Bisphenol-A - containing Plastics: A Quick Summary on Endocrine Disruptors
Details about BPA plastics in food and liquid containers are found at Bisphenol-A, BPA. Excerpts are below.
Concerns about BPA stem from studies in lab animals and cell cultures showing that it can mimic the hormone estrogen. It is considered an "endocrine disruptor," a term applied to chemicals that can act like hormones. But whether it does any harm to people is unclear.
About half a dozen [U.S.] states have banned BPA in children's products ... This year a presidential panel on cancer and the environment said there was a "growing link" between BPA and several diseases, including cancer, and recommended ways to avoid BPA, like storing water in bottles free of it and not microwaving food in plastic containers. Some cancer experts said the report overstated the case against chemicals, but the concerns it raised seem to reflect growing public worries.
OPINION: Readers interested in the subtle but powerful effects of hormone mimicking chemicals and endocrine disruptors that appear in the environment, their sources, effects, and risks, should also see Our Stolen Future, Theo Colborn, Dianne Dumanoski, and John Peterson Myers and discussed at Reviewers below. Quoting from Amazon:
See details about BPA concerns in plastics used to contain food products, atBisphenol-A, BPA.
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Thanks to reader Barbara Stuart
for discussing water storage tank sanitation and concerns for PET plastic water storage tanks - June 2010.
Barrett JR 2010. Attention-Worthy Association: Prenatal Phthalate Exposure and Later Child Behavior. Environ Health Perspect 118:a172-a172. doi:10.1289/ehp.118-a172b, Online: 01 April 2010 - Polybrominated Diphenyl Ethers Induce Developmental Neurotoxicity in a Human in Vitro Model: Evidence for Endocrine Disruption
Web search 06/30/2010, original source: http://ehp03.niehs.nih.gov/article/fetchArticle.action?
articleURI=info%3Adoi%2F10.1289%2Fehp.118-a172b
Quoting: Human exposure to phthalates is ubiquitous due to widespread commercial use. Although the compounds are reported to be rapidly metabolized, concentrations in the body appear to remain fairly stable due to ongoing exposure. The United States and Europe have banned some phthalates from consumer products primarily on the basis of reproductive toxicity data. However, not all phthalates are regulated; meanwhile, research indicates toxicity may extend to other endocrine targets such as the thyroid gland, which is critical for proper neurodevelopment. A new study now reports an association between prenatal exposure to certain phthalates and adverse effects on test scores used to evaluate children’s behavior and executive functioning [EHP 118:565–571; Engel et al.].
Chem-Tainer Industries, 361 Neptune Avenue, West Babylon, NY 11704, Phone: (631) 661-8300, Toll Free: 1-800-ASK-CHEM,
Chem-Tainer Representatives are available 8 AM - 8 PM Eastern Time
Fax: (631) 661-8209800-275-2436, Email: sales@chemtainer.com - Web Search 06/30/2010, original source: http://www.chemtainer.com/watertanks/vertical.aspx
Sax L 2010. Polyethylene Terephthalate May Yield Endocrine Disruptors. Environ Health Perspect 118:445-448. doi:10.1289/ehp.0901253, Web Search 06/30/2010 original source: http://ehp03.niehs.nih.gov/article/fetchArticle.action?article
URI=info%3Adoi%2F10.1289%2Fehp.0901253
Polyethylene terephthalate (PET) is widely used to make clear plastic bottles for bottled water and containers for other beverages, condiments, and cosmetic products. There is concern that estrogenic chemicals such as phthalates may leach into the contents from bottles made from PET, although PET is not a phthalate derivative. Sax (p. 445) describes several studies suggesting that water from PET bottles can have estrogenic activity in some bioassays and that phthalates might leach from PET bottles. The author notes the difficulties in evaluating these studies, especially in cases where there may have been prior contamination of the water or the containers with estrogenic agents or phthalates. Sax suggests that the phthalate content of PET bottles, if present, might vary as a function of the acidity of the product and the temperature and duration of storage. Sax also makes the observation that other nonphthalate chemicals such as antimony, which is used as a catalyst in the polycondensation of PET, might also contribute to the endocrine-disrupting activity of products stored in PET containers. The widespread use of PET plastic for a variety of applications suggests that additional research is needed.
López-Carrillo L, Hernández-Ramírez RU, Calafat AM, Torres-Sánchez L, Galván-Portillo M, Needham LL, et al. 2010. Exposure to Phthalates and Breast Cancer Risk in Northern Mexico. Environ Health Perspect 118:539-544. doi:10.1289/ehp.0901091
Web Search 06/30/2010, original source: http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901091
Keywords: breast cancer, case–control study, endocrine disruptors, environment, Mexico, phthalates, risk assessment, urinary metabolites.
Quoting: Conclusions: We show for the first time that exposure to diethyl phthalate, the parent compound of MEP, may be associated with increased risk of BC [breast cancer], whereas exposure to the parent phthalates of MBzP and MCPP might be negatively associated. These findings require confirmation.
Quoting the Editor's Summary: Phthalates are ubiquitous environmental pollutants used primarily as plasticizers of polyvinyl chloride and as additives in consumer and personal care products. Research has shown that phthalates can have effects on reproductive health and development. Few studies have investigated potential adverse effects of phthalates in women. In a population-based case–control study, López-Carrillo et al. (p. 539) examined the association between urinary concentrations of nine phthalate metabolites and breast cancer. Phthalate metabolites were detected in urine samples in at least 82% of women. The geometric mean concentrations of monoethyl phthalate (MEP) were higher in cases than controls, whereas controls had significantly higher concentrations of mono-n-butyl phthalate, mono(2-ethyl-5-oxohexyl) phthalate, and mono(3-carboxypropyl) phthalate (MCPP) than cases. After adjusting for risk factors and other phthalates, urinary concentrations of MEP were positively associated with breast cancer, and the association w
as stronger among premenopausal women. In contrast, there were significant negative associations between monobenzyl phthalate (MBzP) or MCPP and breast cancer.
Koike E, Yanagisawa R, Sadakane K, Inoue K-i, Ichinose T, Takano H 2010. Effects of Diisononyl Phthalate on Atopic Dermatitis in Vivo and Immunologic Responses in Vitro. Environ Health Perspect 118:472-478. doi:10.1289/ehp.0901255 - Web Search 06/30/2010, original source: http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901255 Diisononyl phthalate (DINP), a principal plasticizer in many polyvinyl chloride products, has been shown to have an adjuvant effect on immunoglobulin (Ig) production in mice. However, the effects of DINP on allergic diseases have not been fully elucidated.
Conclusions: DINP can aggravate AD-like skin lesions related to Dp. The mechanisms of the aggravation might be mediated, at least partly, through the TSLP-related activation of dendritic cells and by direct or indirect activation of the immune cells.
Quoting Editor's Summary Epidemiologic studies have suggested that exposure to phthalate esters such as di-isononyl phthalate (DINP) may be associated with the development of asthma, wheezing, and allergic symptoms. Koike et al. (p. 472) investigated the effects of DINP on the development of another allergic disease, atopic dermatitis. These investigators induced atopic dermatitis experimentally in laboratory animals and then exposed the mice systemically to various doses of DINP for up to 16 days. Clinical scores, histology, protein level of cytokines and chemokines in ear tissue supernatants, and levels of immunoglobulin and histamine in serum were measured at the end of DINP exposure. The effects of DINP on immunologic responses of bone-marrow–derived dendritic cells (BMDCs) or splenocytes were also measured in vitro. DINP exacerbated atopic dermatitis–like skin lesions in a manner consistent with eosinophilic inflammation, mast cell degranulation, and thymic stromal lymphpoeitin expression. DINP also enhanced expression o
f cell surface activation markers on BMDCs and affected systemic immune responses on splenocytes in vitro. The authors conclude that DINP can aggravate atopic dermatitis–like skin lesions in an animal model and that the effects may be mediated, as least in part, through the thymic stromal lymphopoeitin-related activation of dendritic cells and direct or indirect activation of immune cells. These studies provide biological plausibility for other observations in humans, which suggests that exposure to plasticizers such as DINP might be associated with allergic diseases such as atopic dermatitis.
"In Feast of Data on BPA Plastic, No Final Answer", Denise Grady, The New York Times, 7 September 2010, p. D1.
Our Stolen Future: Are We Threatening Our Fertility, Intelligence, and Survival?--A Scientific Detective Story, Theo Colborn, Dianne Dumanoski, John Peter Meyers. Plume-Penguin Publishing, 1997, ISBN 0-452-27414-1., ISBN13: 9780452274143. This book is a seminal work on endocrine disruptors (chemical contaminants having impact at extremely low levels in the environment).
Recommended by Daniel Friedman, this book is a critical update to the landmark Silent Spring by Rachel Carson and discusses the effects of minute trace amounts of chemical contaminants in the environment. The text "Identifies the various ways in which chemical pollutants in the environment are disrupting human reproductive patterns and causing such problems as birth defects, sexual abnormalities, and reproductive failure. Reprint. Tour. NYT."
Amazon.com Review: By O T (Ontario, BC) - 'Our Stolen Future' is a great introduction to one of the most important scientific discoveries in our time. Having recently completed a thesis project at university on Endocrine Disruptors, I have reviewed hundreds of papers on the subject. This book is a good clear overview of the scientific literature on EDs. The authors are experts - Theo Colborn is largely responsible for creating the field by bringing together diverse researchers so they could see the big picture of their work. Many of the principle investigators are interviewed and quoted at length on the way chemicals participate in and interfere with delicate hormonal systems in animals (including humans). The major accomplishment of the book is to make an easy-to-follow story out of complex research. Many resources are available to help you assess the reliability of this story, and the best thing to do if you have any doubts is read review articles in scientific journals (which are easier to understand than technical papers). The Physicians for Social Responsibility (PSR) have a guidebook for health-care professionals on Endocrine Disruptors, and the US EPA has many reports on the matter. Beware of people or websites who try to 'debunk' this book (or the science behind it) by simply declaring it false, flawed or disproven. There is far too much supporting research for so simple a refutation.
OPINION: Significant and discussed in this book is the observation that at certain critical points in the development of animals, presumably including humans, exposure to extremely low levels of endocrine disruptor chemicals (EDC's) (such as BPA - Bisphenol-A or BPA, Diethylstilbestrol - DES, dioxins, PCBs, and chemicals used in the production of certain cleansers, dyes, flame retardants, plastics, pesticides, white papers ) perhaps just a few molecules, or in the parts per trillion, is sufficient to cause disruption of the animal's development, including proper sex differentiation, or the lack of it that produced androgynous ducks unable to reproduce under such conditions.
A endocrine disruptor is a synthetic chemical compound that mimics natural hormones when it is taken into the body of a human or other animal. It "disrupts" the endocrine system by turning on or off normal chemical signals that in turn can affect normal hormone levels, bodily functions, and significantly, the development of embryos. Further, unlike naturally occurring hormones ingested, for example from plants (phytoestrogens), synthetically-generated hormones accumulate in the body and can have a half-life of decades or longer.
One significance of this finding includes the observation that an important medical effect that occurs with exposure to chemicals in extremely low concentrations means that experiments to test for correlations between chemical exposure and subsequent serious medical problems will be deeply flawed if, for example, the experimental design does not include testing for the presence of the chemical at extremely low levels. A related concern is that even if harmful effects from exposure to extremely low concentrations of an endocrine disruptor are occurring, teasing out and proving that relationship can be also extremely difficult.
Silent Spring, Rachael Carson, Mariner Books; Anv edition (October 22, 2002), ISBN-13: 978-061824906. Amazon.com Review: Silent Spring, released in 1962, offered the first shattering look at widespread ecological degradation and touched off an environmental awareness that still exists. Rachel Carson's book focused on the poisons from insecticides, weed killers, and other common products as well as the use of sprays in agriculture, a practice that led to dangerous chemicals to the food source. Carson argued that those chemicals were more dangerous than radiation and that for the first time in history, humans were exposed to chemicals that stayed in their systems from birth to death. Presented with thorough documentation, the book opened more than a few eyes about the dangers of the modern world and stands today as a landmark work.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Branched Drain Greywater Systems, Art Ludwig. Oasis Design. Design, construction and use of "branched drain" greywater systems: a simple design to achieve automated, reliable subsurface irrigation without pump, filter, valves or surge tank, using all off-the-shelf components.
Gravity Flow Water Systems: Handbook of Gravity Flow Water Systems Thomas D. Jordan, Jr. Intermediate Technology Development Group. 1980.
Maruata en el Cruce de Caminos, Art Ludwig. Oasis Design. Ecological systems designs for an indigenous community in Mexico, including water supply and sanitation. See PDF downloadable book at www.oasisdesign.net/design/examples/maruata/book.htm.
"Microbial Problems in Treated Water Storage Tanks", Smith, C., and G. Burlingame. 1994. In Proc. of the 1994 Annual AWWA Conference. Denver, Colo.: AWWA.
Oxidation of Iron and Manganese www.fcs.uga.edu/pubs/PDF/HACE-858-11.pdfIron and manganese dissolve more readily deep underground, in the absence of oxygen. As water is pumped to the surface and exposed to oxygen, the process will reverse and the dissolved iron and manganese will precipitate out of the water forming colored sediment. Iron sediment is reddish brown or orange; manganese sediment is black or dark grey. See also www.healthgoods.com/Education/Healthy_Home_Information/Water_Quality/iron_manganese.htm.
Quality of Water in Storage Grayman, W.M. and G.J. Kirmeyer. 2000. "Protecting Your Storage Tank - An Analysis of Long- and Short-Term Options", Jacobs, K.A. 2000. In Proc. of the AWWA Infrastructure Conference. Denver, Colo.: AWWA.
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications; (February 1, 2007), ISBN-10: 0936070404, ISBN-13: 978-0936070407 More than 28 million households have septic systems, but few homeowners know how they operate or how to maintain them. This clearly written, illustrated guide addresses that need, emphasizing conventional septic systems powered by gravity flow, filtering through soil, and the natural soil organisms that purify sewage. The book discusses maintenance, what to do if things go wrong, and alternative systems such as mounds and sand filters. Additional chapters cover graywater systems, composting toilets, and a unique history of water-borne waste disposal. This expanded edition contains three new chapters.
Tank Construction Procedures Steve Burgess, Edoret Region Company P.O. Box 6495, Eldoret, Kenya. Fax 254-321-62472. sburgess@maf.org.
Technology and Developing Countries, Practical Applications, Theoretical Issues, (Science, Technology, & Development), Routeledge. The relationship between technology and development is explored by economists, policy analysts and other experts. The adoption of technology is studied in five main areas agriculture, energy, infrastructure, the introduction of technology and the success and constraints of technological diffusion as a whole. This volume also examines the technology transfer between North and South from a perspective of training, environmental impact and aid dependency. The emphasis is not placed simply on finding problems, but ways forward are examined. By bringing together both practical and intellectual analysis, this collection signposts future directions in the technology development relationship.
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan. McGraw-Hill Professional, 1991. Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites. - DF note: lacks detail on septic systems.
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