If you’re flushing wet wipes down the toilet, there’s a good chance they’ll end up on a beach teeming with faecal bacteria and posing a health risk to beach-goers. That’s according to a new study published in the journal Marine Pollution Bulletin. 

Scientists at the University of Sterling collected trash from 10 beaches along the Firth of Forth estuary in Scotland and discovered sewage-associated plastic waste at everyone one. This included an unpleasant array of soiled wet wipes, used cotton buds, and sanitary products that had likely been flushed down the toilet.

After taking the samples of the flushed trashed back to the lab, they discovered they were riddled with harmful bacteria usually found living in human poop, including E. coli, enterococci, and Vibrio spp, which can cause stomach upsets and severe disease. 

When they compared levels of bacteria on the plastic trash to those on natural substrates, like seaweed and sand, they found that wet wipes and cotton buds were higher in levels of faecal bacteria. This suggests that the flushed plastic trash is especially prone to harbouring harmful germs compared to natural materials you find by the seaside. 

Worst still, they found high rates of antimicrobial resistance present in the bacteria on the wipes and cotton bud sticks. Many of the bacteria had evolved resistance to commonly used antibiotics, including amoxicillin, ampicillin, and cephalexin.

“We all know that sewage waste on our beaches is unsightly, but it could also be a risk to public health,” Professor Richard Quilliam, study author and a Professor in Biological and Environmental Sciences at the University of Stirling, said in a statement.

“Finding faecal bacteria could also indicate the possibility of other human pathogens such as norovirus, rotavirus, or salmonella,” added Rebecca Metcalf, lead study author and PhD researcher from the University of Stirling.

“The extent to which people could be exposed to these pathogens is beyond the scope of our study, but obviously there’s always a risk of children picking up and playing with wet wipes or other plastic waste on the beach.”

The study provides yet another good reason why you should avoid flushing wet wipes and baby wipes down the toilet – even if their packaging sneakily suggests they may be “flushable.” Even beyond their threat to public health, wet wipes can cause a real problem with sewers. It’s estimated that wet wipes make up around 93 percent of the material causing sewer blockages in the UK. 

You might remember the case of giant “fatbergs” clocking up the sewers beneath England. One discovery near Devon around Christmas 2018 included a 64-meter-long (210 foot) clump of congealed cooking oil, gelatinous gunk, soiled wet wipes, diapers, and sanitary towels.