Plastics - Building Biology
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Plastics have infiltrated every part of our kitchen from building materials to containers and cookware. In 1987, Ana Soto and Carlos Sonnenschein at Tufts University in Boston discovered that a chemical leaching from the plastic test tubes caused a rapid growth in breast cancer cells (Soto et al, 1991). This was the first time that scientists became aware of hormone altering chemicals in plastics. Since then there have been a flood of studies on the adverse health effects of plastics – namely PVC, polycarbonate and polystyrene because they contain the hormone altering chemicals DEHP, bisphenol-A (BPA) and nonylphenol respectively. These xeno-oestrogens adversely affect the reproductive system with mounting evidence to suggest they could be responsible for early puberty and increased rates of testicular and breast cancer. They are also suspected to play a role in obesity, diabetes and heart disease (Environment California, 2007).

The recycling number at the bottom of the plastic container will inform you of the type of plastic it is made of. Plastic containers and bottles that don’t have a number on them should be avoided.

TV INTERVIEW: Here is my interview on plastics on Channel 10 The Circle

PODCAST: The Good Doctors. Household plastics – are they safe? Itunes Store. Nicole Bijlsma. (20 minute interview)

Plastics to Avoid

# 1 Polyethylene terephthalate (PET or PETE) is the most commonly used plastic for disposable water bottles, soft drinks and in cleaning products because it is the most recyclable of all the plastics. This plastic degrades rapidly when exposed to heat or when washed and was not designed to be reused. Whilst phthalates or other softening additives are not used in the manufacture of PET, recent reports suggest they may leach into the water causing an oestrogenic like effect (Wagner and Oehlmann, 2009; Pinto and Reali, 2009; Montuori et al, 2008). These phthalates may arise from recycled PET that was previously used for personal care products which imbed themselves in the plastic and cannot be eliminated simply by washing the plastic. As such it is not recommended to store food or liquids in this plastic.

#3 Polyvinyl chloride (PVC) is used in a variety of food packaging including some types of cling wrap, storage containers, juice bottles, as well as in water pipes and some toys. It is one of the most toxic of all the plastics as the plasticizers used to make it flexible are phthalates including DEHP (diethylhexyl phthalate) and benzyl butyl phthalate (BBP). As a result of their impact on male reproduction, and the fact that they easily leach because they are not chemically bound to the PVC, they are banned for use in toys and cosmetics in the European Union.

#6 Polystyrene (PS) is used in a wide variety of applications from disposable cups, plates, trays and cutlery to take-away containers; yogurt and margarine containers, egg cartons, number plates and so on. There are serious concerns associated with the migration of contaminants into the food or drink such as nonylphenol which is an endocrine disrupter and benzene – a known cancer causing agent.

#7 all other types of plastics such as BPA. There are both safe and unsafe plastics that fall into this category. One of the unsafe plastics is polycarbonate (PC) used in plastic baby bottles, drinking water bottles and storage containers because it contains BPA (bisphenol A). Number 7 bottles should be avoided unless you know what type of plastic it is made of and its health impact.

If you’ve ever wondered where all of our consumer products come from and where they go, watch the Story of Stuff– a brilliant 20 minute animated video.

Safer Plastics

#2 High Density Polyethylene (HDPE) is a hard plastic commonly used in water bottles, milk cartons, fruit juice bottles, detergents and shampoos, margarine tubs, as well as some toys and shopping bags. HDPE is one of the most recycled plastics and is more stable than most other types of plastics and does not leach endocrine disrupting chemicals into the water.

#4 Low Density Polyethylene (LDPE) is a soft, flexible plastic used in garbage and grocery bags, squeezable bottles (eg honey), cling films, flexible container lids and some sports water bottles. Unlike HDPE, LDPE is not recyclable and therefore creates an environmental concern.

#5 Polypropylene (PP) is used in rigid containers such as ice-cream and yoghurt containers, drinking straws, syrup bottles, diapers, margarine tubs, microwaveable ware, disposable take-away containers, domestic water pipes, some drinking water bottles, as well as disposable cups and plates. Whilst it is suspected to be free from any known hazards, it is not recyclable.

NEVER heat or freeze food or liquids in any plastic containers as it will leach contaminants into the food.

Are BPA-Free Plastics Safe?

Are BPA free plastics safe or are they just a reaction by manufacturers to satisfy consumer confidence? In light of the fact that ALL PLASTICS LEACH CHEMICALS, especially the hotter they become, I would not recommend them to store certain foods and beverages. Click here to find out more.


Hormone altering chemicals found in PVC, polycarbonate and polystyrene plastics should be banned to store our food or beverages because they have been linked with premature puberty, obesity, diabetes, sperm defects and infertility.