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Flint may not be alone

The Guardian is reporting that lead contamination may be a problem “in every major city east of the Mississippi,” and that, as in Flint, contamination may be deliberately covered up by local water utilities through a loosely organized program of test gaming.

Lead isn’t very soluble in water. If you want your tests to come out low, all you have to do is flush the pipes before you test them. This is exactly what utilities have been doing; on the small scale, by telling residents to run their water for several minutes before collecting samples, on the neighborhood scale by selecting areas with high utilization (and thus faster turnover), and on the system scale by flushing mains. All of these practices run contrary to federal guidelines, but very little is being done to stop utilities from using them to game their lead results.

It’s important to note that the Guardian piece doesn’t indicate that there exists any affirmative evidence of contamination, but rather a testing regime that seems more about avoiding blame than in protecting people. For example, Michigan’s instructions for lead and copper drinking water sampling require the resident to flush the line for at least five minutes, and then sample six hours later. It would probably be better to start by asking residents to collect water samples in whatever way they normally draw water for drinking, cooking, bathing or washing, and then follow up with line-flush tests (and other tests) to help isolate the source of contamination if any is found. This kind of test minimizes the chances contamination will be detected.

When you are monitoring for something as dangerous as lead, a well-designed surveillance program should start with preliminary tests with a low false-negative rate. If you see lead, you should always do something. Line-flush tests are probably useful for isolating certain sources from others, but a the expense of a higher false-negative rate. If lead is getting into the water, the only ethical thing to do is hunt down the source and then decide who has to pay for it. If it turns out to be the homeowner’s pipes, then at least they can make an informed choice about what action to take. If it’s the city’s pipes, or the utility’s pipes, then, well, that’s what bond issues are for.

Even the coldest equations demand a more proactive approach. Caring for brain damaged children who grow up to be brain damaged adults is guaranteed to be more expensive than digging some holes.

Russell Neches

A microbiology graduate student at UC Davis, working with Jonathan Eisen @phylogenomics . Studies evolution & ecology. Advocate of Open Hardware & Open Access.

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