Reuse of water bottles

Reusable mineral water bottles in crates.

Old crate with beer bottles.

Reusing single-use bottles is a common domestic practice. Typically the bottle is washed out with warm soapy water after each use. Periodically a bleach solution may be employed to kill bacteria. Washing and re-using bottles cuts down on waste and landfill, and drinking tap water is much less resource-intensive than buying commercially bottled water.

Bacterial concerns

The biggest risk for reusing bottles is that bacteria could develop in the bottle between uses. Thus some elect to clean the interior with warm/hot soapy water and let it fully dry before re-filling. New Zealand Food Safety Authority recommends the concept of using plastic bottles only once; not for carcinogenic reasons, but for matters of bacteria. Mouth contact to the bottle openings can easily transfer bacteria to the water content which can subsequently contaminate both bottle and water. The contamination will result in bacterial and fungal growth in the water while kept in storage except if you cleaned the bottle very well before reuse .

Other chemicals of concern

Bisphenol A (BPA) can be a concern for some bottles made of polycarbonate (which shares resin identification code 7 with other plastics). High temperatures and bleaching are believed to increase leaching of BPA. Several countries have banned the use of plastics containing BPA used for water and other food items.

Leaching of phthalates from PVC (resin identification code 3) is also a concern, but PVC is not typically used for water bottles.

DEHA is neither regulated nor classified as a human carcinogen by the U.S. Occupational Safety & Health Administration, the National Toxicology Program or the International Agency for Research on Cancer, the leading authorities on carcinogenic substances.

Further, DEHA is not inherent in PET as a raw material, byproduct or decomposition product. DEHA is a common plasticizer that is used in innumerable plastic items, many of which are found in the laboratory. For this reason, the student’s detection of DEHA is likely to have been the result of inadvertent lab contamination. This is supported by the fact that DEHA was detected infrequently (approximately 6% of the samples) and randomly, meaning that the frequency of detection bore no relationship to the test conditions.

Moreover, DEHA has been cleared by FDA for food-contact applications and would not pose a health risk even if it were present. The American Cancer Society has suggested that there is no risk from DEHA in plastic bottles.

Finally, in June 2003, the Swiss Federal Laboratories for Materials Testing and Research conducted a scientific study of migration in new and reused plastic water bottles from three countries. The Swiss study did not find DEHA at concentrations significantly above the background levels detected in distilled water, indicating DEHA was unlikely to have migrated from the bottles. The study concluded that the levels of DEHA were distinctly below the World Health Organization guidelines for safe drinking water.

See also

• Bottled water
• Reuse
• Waste hierarchy

Further reading

• Oliphant, J.A., M.C. Ryan, and A. Chu, 2002. Bacterial Water Quality in the Personal Water Bottles of Elementary Students’. Canadian Journal of Public Health. 93(5):366-367.