A teenager peed into one of Portland, Oregon's drinking water reservoirs – a 38-million gallon repository of good, potable H2O – and now the city intends to drain it. This is a very, very dumb idea.
Above: Mt. Tabour Reservoir #1, the body of water into which the teenager peed. Photo Credit: viper007bond via DeviantART
How dumb? Slate's Laura Helmuth and AP's Seth Borenstein ran some numbers:
...a typical urination of about 1/8 gallon in a reservoir of 38 million gallons amounts to a concentration of 3 parts per billion. That's billion with a b. For comparison, the Environmental Protection Agency's limit for arsenic in drinking water—arsenic!—is 10 ppb.
The EPA doesn't appear to have a limit for urine in drinking water, but it does limitnitrates in drinking water to 10,000 ppb, and urine does contain a lot of nitrogen, so let's use that as a proxy.
How many times would that teenager have to pee in a Portland reservoir to produce a urine concentration approaching the EPA's limit for nitrates in drinking water? About 3,333 times.
But of course urine is 95 percent water. (If you're ever trapped in rubble after a natural disaster, go ahead and drink it.) Only about 2 percent of urine is nitrogen-rich urea. That means he'd have to urinate 166,666 times for the concentration of urea to approach that of the EPA's limit for nitrates in drinking water.
According to the Associated Press, Portland Water Bureau spokesman David Shaff says it is well understood that the urine poses little risk, but that the city has opted to do away with the water anyway due to what he calls "a perceived difference."
"Our customers don't anticipate drinking water that's been contaminated by some yahoo who decided to pee into a reservoir," he said.
Do your customers anticipate paying to drain 38-million gallons of water that everyone admits is perfectly safe to drink, just because there is security cam footage of somebody peeing in it? What about the stuff that winds up in the drink that we don't have video footage of? Odds are high an animal has straight up died in that reservoir. This is literally an open, exposed pool of water we're talking about. How picky can the city really afford to be, when it comes to what does and does not enter its uncovered water supply? Who exactly is the bigger yahoo, here?
Dammit, Portland, you're supposed to be cooler than this. Get your act together.