Single use plastic water bottles are very bad for the environment, typically because they are not recycled and are often thrown out. The plastic takes centuries to full decay and as plastic decays it leaks dangerous chemicals into the groundwater and soil. Even if plastic is recycled, it might not be recycled properly and would still need to decay on the earth. The total carbon footprint of one plastic water bottle is about 828 grams of carbon dioxide. Lots of college students use single use plastic bottles for water, coffee or any other drink. These cups are typically thrown away, adding to the amount of plastic waste in the world. This chart shows that the average number of single use plastic bottles per week is 3.9 amongst the sample size that I gathered data from. The lowest number per week was 0, due to my friend’s constant usage of a reusable water bottle and the highest number was 9. That means per week a college aged student similar to my friends would use 3.9 single use bottles adding up to a 3229.2 grams of carbon dioxide per week released due to this plastic waste. 
sources: https://www.greenamerica.org/blog/truth-about-bottled-water
I was also considering on doing the same topic- number of plastic water bottles per week, so I find this topic interesting. The graph is super easy to understand, but it is even easier to understand seeing that you provided info such as the average number of bottles used, as well as the amount of carbon dioxide released per week.
People love plastic bottles. They are convenient and affordable. I know of a corner store around the corner from where I live that sells big 20 oz. water bottles for $ 1.00.
It’s a really interesting study to look at water bottle usage from your friends and then calculate the grams of CO2 used. This helps us as Union students get a better understanding of our own sustainable or unsustainable habits.