Plastic bottles, these days, are used everywhere. Whether you want to store your water, milk, oil, any kind of drink, etc., plastic bottles are cheapest and go-to option. But this answer is not about plastic bottles and where they are used. This is answer is specifically about the symbols you find at the bottom of such bottles.
Most of the people who are reading this must have seen some labelling at the bottom of those plastic bottles(water bottle, milk containers, or any other container made out of plastic). I surely don’t expect you to recall those symbols as you read this answer, because, anyways, who keeps them in mind?? We usually think it is the companies’ logo and stuff that simply doesn’t matter to us.
But trust me, it does matter! The world today is increasingly becoming conscious about the wellbeing of the environment and human health. In this scenario, one particular kind of symbol that we see at the bottom of our plastic bottles, has a very crucial message to convey, which makes it important that we check this symbol before we buy any plastic container, esp. for water storing purposes.
These symbols are called recycling numbers. Most commonly you will find bottles with number 1(inside the triangle), and 2 or 5. These numbers vary from 1 to 7 and very often they are accompanied by some capital letters written below the recycling triangle symbol.
These symbols are of huge importance esp. for recycling companies, because it tells them what can they do with them. For example, if a trash picker picks a plastic container with number 4 inside the triangle, and has the letters LDPE below it, then the recycling factories won’t accept it, because they cannot recycle it. But plastics with symbols, 1 and 2 are readily acceptable by them.
More that this industrial meaning, it also has a meaning which should concern a health-conscious person. Not all plastic containers are safe for storing food items!
The most common symbol that you will find in water bottles made out of plastic is 1-PETE or 1-PET(both are same). This means that the container is made out of PolyEthylene Terephthalate(PET), and are meant for single use only! They are usually used to make 1-time use water bottles and soda bottles.
One thing that you should know that PET has a terrible chemical property that it has only decent chemical resistance against chemicals including water. Only up to 70°C, they don't affect the water in the bottle but at temperatures higher than that, the plastic molecules will tend to dissolve into your drinking water, and consuming such water can be a cause of cancer!
Read this article by economics times about cancer causing effects of plastic bottles
Hence if you are using plastic-made water bottle marked with 1-PET, it would be extremely stupid idea to drink hot water off of it, or even to reuse it.
But there is something worse going on in the market, at least in India, where I live. If you go to market to buy a plastic water bottle, most probably you will find bottles with mark 1-PET. And many people reuse 1-PET bottles as their regular water bottle which is injurious to your health in long run.
For the purpose of hot water storing and having reusable water bottles, there are water bottles with mark “2-HDPE”(High Density PolyEthylene). HDPE has an amazing temperature range, and is considered safe for short periods up to 248°F (120°C) or for long periods up to 230°F (110°C). Since boiling water never gets above 100°C, this means that anything boiling and below is safe. Hence containers made out of them are also called food-grade bucket.
The numbers also contain the information about which of them is recyclable and into what it can be recycled. The image below summarizes most of the info!
Thus, next time if you go to market to buy a plastic bottle, make sure you buy only those with mark 2-HDPE on them. This way you could avoid unnecessarily inviting cancer into your body!
Check your regular plastic water bottle and let me know in the comments that are you too drinking from 1-PET bottles??
Reference: World Cancer Day: Here's why you should stop drinking water from plastic bottles
