Increasing consumption of water packaged in plastic containers in Cypriot and other Mediterranean countries continues to compete with tap water for the most popular water source of potable use, cooking, and beverage preparations (cold/hot coffee, tea and juices). A general notion in the Cypriot society calls for precautionary measures against packaged water quality deterioration during container exposure to high temperatures and/or extended sun (UV) radiation, because they are considered as important factors of plastic constituent leaching into water. Newly published research by the prestigious Water Research Journal shows for the first time that frequency of container re-use, neither temperature, nor UV exposure duration was the most significant factor in maximizing chemical leaching from polyethylene terephthalate (PET, Plastic Identification Code #1, 1.5L) and polycarbonate (PC, Plastic Identification Code #7, 19L) types of water containers (http://www.sciencedirect.com/science/article/pii/S0043135411005884).
The research team of the Cyprus International Institute for Environmental and Public Health (CII) under the auspices of the Cyprus University of Technology (CUT) partnered with faculty from Harvard School of Public Health (HSPH) to investigate the comparative influence of frequency of re-use, temperature and UV exposure duration on antimony and bromine leaching from plastic water containers. Even under ambient temperatures and no UV exposure (stored in dark conditions), frequency of reuse significantly (p<0.001, 95% confidence level) increased the magnitude of chemical leaching into packaged water.
The research team led by assistant professor, Konstantinos C. Makris, post-doctoral researcher, Syam S. Andra, and HSPH faculty member James P. Shine reported for the first time that the number of times a plastic container was reused mostly determined the magnitude of antimony and bromine compounds leaching into water. Plastic constituents such as antimony and bromine compounds, like polybrominated diphenyl ethers (PBDEs) are widely used as PET polymerization catalyst and flame retardants, respectively, posing a serious health risk under conditions that enhance their leaching into packaged water. In developing countries, plastic containers are extensively re-used for solar disinfection treatment of microbial-contaminated water via the placement of contaminated water in plastic containers under the sun for a specific period of time (SODIS treatment). Research has shown that microbes and viruses are eliminated from the SODIS-treated water allowing its subsequent potable use, but little is known about possible chemical leaching under the aforementioned conditions, which were explored in our study.
Ongoing research in Prof. Makris’ lab attempts to quantify the magnitude and uncertainty associated with leaching of organic plasticizers used in water containers, such as bisphenol A, phthalates, and PBDE compounds held responsible for possible endocrine disrupting health effects in humans. Currently, no acceptable daily dose estimates exist for oral ingestion of organo-brominated (PBDEs), or other plasticizers/additives organic compounds if they were to be found in bottled water at much lower concentrations. The dilemma about recycling promotion of plastic containers versus extensive re-use and the possible health hazards associated with bottle reuse needs to be evaluated under a holistic approach. Suggestive intervention measures focus on reducing the number of times plastic containers are re-used, while also caution should be exercised in minimizing container exposure to heat and sunshine (UV radiation).