It is quicker to list everything that has not been linked to causing cancer:

There, I think I got everything.

For reproductive outcomes (sperm quality) and digestive outcomes (immunosuppresion) we rated overall body evidence as “high” quality and concluded microplastic exposure is “suspected” to adversely impact them.

For reproductive outcomes (female follicles and reproductive hormones), digestive outcomes (gross or microanatomic colon/small intestine effects, alters cell proliferation and cell death, and chronic inflammation), and respiratory outcomes (pulmonary function, lung injury, chronic inflammation, and oxidative stress) we rated the overall body of evidence as “moderate” quality and concluded microplastic exposure is “suspected” to adversely impact them.

We concluded that exposure to microplastics is “unclassifiable” for birth outcomes and gestational age in humans on the basis of the “low” and “very low” quality of the evidence. We concluded that microplastics are “suspected” to harm human reproductive, digestive, and respiratory health, with a suggested link to colon and lung cancer.

Future research on microplastics should investigate additional health outcomes impacted by microplastic exposure and identify strategies to reduce exposure.

None of that is very definitive or quantitative at all - even the high quality data only gives a suspected adverse impact. Overall not really very actionable. It is probably not very good for us and something we should be working to reduce. If for no other reason than all the other problems we know excessive plastic production is causing.