Here’s a piece from the ABC series “War on Waste”, comparing different menstrual products: ““Tampons, pads, menstrual cups, period underwear: What's best for the environment?”
Unsurprisingly it concludes that menstrual cups and menstrual underwear have the least environmental impact. It’s an informative piece – for example describing all the clogged up pipes and waterways from people flushing tampons down the toilet – but I think some of the emphasis on personal guilt is unhelpful. There are lots of other reasons to think about the best option.
The piece also continues a common misconception that you need to rinse a cup out in public: "but if I'm at work, and I want to change it, I'd have to change it at the sink. That doesn't feel right," Jess says.
While you could rinse out the cup in public (and some people certainly do), in practice many cup users instead (and perfectly safely) either rinse it in the toilet (with bottled water, or wiping down with paper), or don’t change it in public at all. An advantage of cups is you only need to change them every 12 hours. Instead you can wash them at the end of the day at home. For this reason some people find cups less awkward at work, as you don’t have to cart disposable products back and forth.
Just a few thoughts – no option is perfect for everyone for all situations or people.