Reusable water bottles: glass, metal or plastic – which is healthiest for you, and best for planet Earth?

Reusable water bottles make staying hydrated easy, and cut down on disposable plastic use. There’s little wonder that they’re such big business. A May 2019 report from MarketWatch valued the industry at US$239 million and predicted the sector will reach a value of US$374 million by 2025. Reusable bottles could become even more popular if more companies, airports and universities follow the lead of Facebook, San Francisco International Airport and the University of Hong Kong in banning single-use bottles. Most bottles are made of one of three materials: plastic, metal or glass. We consulted some experts for their take on the materials’ safety and sustainability. 1. Glass “Glass would be the best [safety-wise] if it didn’t break,” says John Swartzberg, a clinical professor at the University of California at Berkeley School of Public Health. Because glass is made of natural materials, there is no danger of inorganic chemicals leaching into liquids when the bottle is heated or cooled. It also doesn’t hold flavour – some people complain that water in plastic or metal bottles tastes like chemicals or tin. Glass tends to be heavier than metal or plastic, however. If you worry about breakage, there are heat-resistant and shatterproof options. But according to Eric DesRoberts, senior manager at Ocean Conservancy’s Trash Free Seas programme, shatter- and heat-resistant glass are usually more difficult to recycle because they’re created through a different production process. You should separate these items from your other recyclables and check with your local recycling facility to see what it accepts, he says. 2. Plastic Most reusable plastic water bottles are manufactured from plastic polymers such as polypropylene and copolyester, which makes them light and durable. (Reusing single-use water bottles, which are often made from No. 1 or PET plastic, isn’t advised because repeated use can break down the material, which could allow bacteria to build up in cracks, and washing in hot water can cause chemical leaching.) Many reusable plastic bottles are advertised as being free of bisphenol A (BPA), commonly used in plastics until studies linked it to hormonal disruptions in humans. “Most plastic bottles today are not using BPA,” Swartzberg says. “The problem is they’ve replaced BPA with other things, and we don’t know about these other things that they’ve replaced them with.” Until more research has been done on these alternatives, R. Thomas Zoeller, an endocrinologist and professor at the University of Massachusetts at Amherst who has studied the chemical effects of BPA extensively, recommends glass or metal over plastic bottles. Although the effects of bisphenol S, a compound often used instead of BPA, haven’t really been studied in humans, some animal studies have suggested that it could be disruptive. If you use a plastic water bottle, even if it’s labelled as BPA-free, Zoeller suggests hand-washing it because the combination of heat and detergent, which acts as an abrasive, can score the plastic. “It’s a combination of the abrasive and the temperature, and those two things are going to enhance leaching,” Zoeller says. “All plastics that are going to be reused need to be washed by hand. As a rule, I wouldn’t put plastics in the microwave or dishwasher, period.” All plastics that are going to be reused need to be washed by hand. As a rule, I wouldn’t put plastics in the microwave or dishwasher, period R. Thomas Zoeller, endocrinologist and professor at the University of Massachusetts at Amherst A spokeswoman for the Plastics Industry Association says the industry follows FDA regulations about plastics safety. She suggests that consumers who are concerned about washing plastics read the labels and symbols on the products to ensure they’re using them safely. As for recycling, before you buy a plastic bottle, you can check its underside to find the plastic’s classification number. That will tell you what type of plastic the bottle is made of. “In the US, PET (#1) and HDPE (#2) are the most commonly recycled plastics,” DesRoberts says. “However, not all recycling programmes work the same, so it’s important to know what your local recycling centre accepts.” 3. Metal Most metal water bottles are made from stainless steel or aluminium. “Metal obviates any concerns we have, rightfully or wrongfully, about plastic,” Swartzberg says. There may be a slight transfer of aluminium into the liquid, but there’s probably no greater risk than using stainless steel or aluminium cookware, which is deemed safe, Swartzberg says. “Generally I feel more comfortable with glass than plastic, but I think stainless steel has a lot to offer in terms of not having things leach into the water,” Zoeller says. It’s best to make sure that whatever metal bottle you’re buying isn’t lined with plastic, epoxy or resin, which some manufacturers do to mask a tinny taste, because of concerns that those materials could contain harmful chemicals. It’s possible to recycle stainless steel bottles, but their make-up makes them hard to compress in normal recycling processing plants. Most metal water bottles are made from stainless steel or aluminium. “Metal obviates any concerns we have, rightfully or wrongfully, about plastic John Swartzberg, clinical professor at the University of California at Berkeley School of Public Health From a sustainability standpoint, no one material is preferable to another, experts say. “It’s really the reuse over single-use that matters,” says Sara Wingstrand, a former material scientist who works as a project manager for the Britain-based Ellen MacArthur Foundation and calls herself material-agnostic in this case. She says your choice of water bottle should come down to lifestyle considerations, such as how much weight you can carry and your aesthetic choices. “Your best bet is to pick a material that you know you will hold on to longest and use the most,” Nicholas Mallos, senior director of Ocean Conservancy’s Trash Free Seas programme says. From a safety standpoint, Zoeller would avoid plastic. “From a scientific point of view, it’s hard to say something is safe because not everything can be studied, but I think it’s useful to say it’s safer to use glass or metal,” Zoeller says. But there’s probably no reason to lose sleep over your water bottle causing you harm. “All of these products, with the exception of BPA, carry minimal risk,” Swartzberg says. The key here is to make sure you’re using the bottle to consume water. “I think it’s great to see consumers drinking water as opposed to drinking soft drinks,” he says.

Reusable water bottles: glass, metal or plastic – which is healthiest for you, and best for planet Earth?

.css-1mniedq{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;} No matter their composition, reusable water bottles help cut down on single-use plastic. But how healthy are they? Experts give their opinions on which eco-friendly material is best for us

No matter their composition, reusable water bottles help cut down on single-use plastic. But how healthy are they?

Experts give their opinions on which eco-friendly material is best for us