I'm quite sure that's autosuggestion. I was kayaking on the Thames too (up in Richmond/Teddington), but on marathon/sprint kayaks which are very narrow and uns

I'm quite sure that's autosuggestion. I was kayaking on the Thames too (up in Richmond/Teddington), but on marathon/sprint kayaks which are very narrow and unstable, so most people in the kayaking club (hundreds of people!) flipped pretty regularly. We also went to swim from the pontoon in the summer every weekend for years. I can't recall anyone experiencing a persistent metallic taste, and I'm only aware of a single case of food poisoning in the club over the five years I was an active member, and that could be anything. I do remember seeing seals, fishes, eels, kingfishers, herons, and cormorants though. The Thames is a lovely river with bad reputation because of the silt that tides are constantly churning up, and the only problem left (sewer overflows during heavy rain) will be finally gone next year when https://en.wikipedia.org/wiki/Thames_Tideway_Tunnel https://en.wikipedia.org/wiki/Thames_Tideway_Tunnel goes operational.