The group are worried about the record amounts of raw sewage being pumped into waterways.
The “Salty Selkies” swam for more than six miles from the Bass Rock to Craigleith, Lamb and Fidra in the Firth of Forth.
from: BBC News Hannah Russell and debutant Reece Dunn both win swimming golds for Great Britain at the Tokyo Paralympics.
from: BBC News Want to know what’s happening when in the Tokyo Paralympic Games? Check out our comprehensive guide to all the action.
from: BBC News Waterways have become increasingly popular places to swim, especially with pools closed in lockdown.
From missed medal targets to funding cuts – how Team GB’s swimmers have gone onto succeed in Japan and how bright does the future look heading towards Paris?
Charlotte Worthington wins a dramatic BMX park freestyle Olympic gold as Great Britain’s swimmers complete historic Games.
from: BBC News Watch some of the best moments from the early events of day five at the Tokyo Olympics including a gold and silver for Team GB.
It is thought 28 people have lost their lives in open water during the recent hot weather.