Monday, 10 February 2014

Is it safe to reuse plastic bottles?

by Rachel Argo

Typically, I will buy a bottle of water and re-use it until I loose it. We all know that re-using a plastic bottle is good for both the environment and our pockets, but by doing this are we increasing our risk of exposure to ‘dangerous’ chemicals in the plastics? Recently bottles have been designed and marketed as being ‘BPA free’. But what is BPA and why have we never heard of it before?

Maybe you have seen strange shaped bottles with coloured filters appearing in people’s handbags, at the gym or on the high street? ‘Bobble’ bottles are an example of these BPA free plastic products. They are made from recycled materials, are recyclable and contain replaceable filters that claim to remove impurities in the water and improve the taste. Bisphenol A (BPA) is a synthetic organic molecule that is used to make certain plastics such as ‘polycarbonate’. Polycarbonate is commonly used to make household items like drinks bottles and tupperware. BPA is also found in epoxy resins that are used to line drinks cans and tins. We come into contact with plastic all the time and admittedly it would be very difficult to exclude from our day-to-day lives. Until recently no one questioned the effect of this plastic heavy lifestyle on our health, so should we stop re-using that water bottle and buy a BPA free one?

Studies have suggested that BPA possesses the ability to pass from the containers to the food or beverages inside. The concern around this possible seeping stems from the chemical’s ability to act as a mimic of the hormone oestradiol and therefore have potential to interrupt hormone patterns and signaling pathways. Animal studies in rats and mice have linked BPA exposure to a range of health problems such as obesity, fertility impairment, respiratory disorders and inflammation, however there is little or no research into the effects on humans and no single study that conclusively proves that BPA is the cause of these diseases. 

A review in 2006 by the European Food Safety Authority (EFSA), concluded that the Tolerable Daily Intake (TDI) of BPA was 0.05 mg/kg body weight/day. This value is an estimation of the amount of BPA that can be ingested per day per kg of body weight daily, over a lifetime without significant risk to health. BPA is licensed by the EU for use in food contact materials, however a directive in January 2011 prevented the use of BPA containing plastics in the manufacture of baby bottles. The most recent review of the molecule’s safety (July 2013) provisionally suggests that diet is the main source of exposure, that the estimation of this exposure is much lower than EFSAs previous estimations and well below the suggested TDIs. 

Due to the lack of conclusive evidence of BPA safety in humans and changing opinion on TDI values, it is hard to decide if it is worth investing in a BPA free bottle. I initially thought that this was a trendy case of false science, but on closer inspection it seems there may be some truth in their safety claims even if we have not established the extent of it.