One study estimates that 878 tonnes of plastic microfibers are released from Canadian and U.S. household laundry through wastewater treatment plants every year.

Notes:

This is the equivalent weight of 10 blue whales collectively into rivers, lakes and oceans.

Clear methodology, but not peer-reviewed.

Primary Source:

2019 - https://assets.ctfassets.net/fsquhe7zbn68/4MQ9y89yx4KeyHv9Svynyq/8434de64585e9d2cfbcd3c46627c7a4a/Research_MicrofibersReport_191004-e.pdf

Secondary Source:

---