By my calculations, an adult bladder can hold an average 500 ml of urine. But over 90 minutes (not counting for sweating in the sun) 150–200 ml accumulate and this quantity triggers a need to urinate. Funny though, even when I count say 500 adults on a section of the beach, I don’t see a large percentage of them entering the toilets every hour. That’s 75–100 litres of urine unaccounted for. Could it be that most people pee in the sea?
The American Chemical Society advocates peeing in the sea. They explain that human urine is a fertiliser for marine algae. Its composition is more than 95 per cent water with 1–2 g/L dissolved salt, 0.75 g/L potassium as well as 9 g/L urea. This is a nitrogen by-product from the digestion of protein. Combined with seawater, it’s converted to ammonium.
The Society also believes that dilution is the solution to pollution. If at one time, every person on the planet all urinated at once in the Atlantic, the total fertiliser would only be a minute 60 parts per trillion.
Some surfers might grin in relief, continuing to rinse their wetsuits after use and occasionally washing them with special brand name products to alleviate pissy odours. Some male kayakers might be more open about carrying bottles or even sponges to collect urine, which is then disposed of overboard. To help them make use of these same receptacles, female kayakers can choose from an array of disposable or reusable ‘female funnels’.
But the strength of the Society’s paper calculations disintegrate in the real ocean. The process of dilution is uneven. Attractive bays, reefs and lagoons all have calmer, warmer waters. Endless swashes of tourist urine fertilise the algae, which overwhelm and kill the corals.
The composition of adult urine also varies. Your doses of drugs such as paracetamol, ibuprofen, antibiotics, anti-depressants, oral contraceptives and hormone replacements are not entirely absorbed by your body. The same is true for caffeine, opioids, cannabis, amphetamine, cocaine and ecstasy. Your kidneys funnel them into your urine.
Even the oxybenzone from sunscreen and chemicals from various beauty products and insect repellents applied to your skin or hair are handled by your kidneys in the same way. Thirty minutes after you use them, these chemicals appear in your urine.
Fish, shrimp and crabs react badly to these pharmaceuticals. Their behaviour changes. Some become restless and clumsy, picking fights with others, going out when they should take cover, reacting slowly: all this leads to early deaths. Fish, shellfish and amphibians exposed to hormones and oxybenzone can also completely or partially change sex, usually becoming infertile. Eggs or larvae develop abnormalities.
Are sharks attracted to human urine? Some biologists claim that attacks are linked with the release of human urine. Others claim sharks are not at all interested in these excretions or in human blood.
But sharks will respond to the presence of fish urine and blood. Marine fish urinate constantly through their gills: taking in salt water and excreting salt. Their kidneys conserve water so their urine is quite concentrated. So large schools of fish send constant biochemical signals that are interesting to sharks. Being in that mix, you could simply become collateral damage.
So here’s a simple protocol for adults: Don’t pee in the sea. Urinate at your home or public toilet in the hour before you enter the sea. Start counting from the time you leave home. Physiologically, as your warm body enters the cooler water, the contrast can trigger an urgent need to pee even if your bladder holds only a little urine. If you were just at the loo, you can confidently override that sensation.
If you are at some idyllic place without a public toilet, find a quiet spot with some groundcover. Make a small deep hole, urinate and cover well. Now wildlife won’t be attracted to the salts and chemicals, which can have dire consequences for them.
Of course, young children can be forgiven in breaking the protocol, but we can start training them by explaining our own behaviour. Choosing this attitude, holding to a human urination ethic is the best way we can finally explain ourselves to all the baby fish, oysters and corals.