An ongoing process

By Published by The Editorial Board

Published: July 8, 2008

Dan River water was recently tested for 88 different substances at minute levels — parts per trillion.

The one thing Danville wanted its water customers to know before the testing — that the city’s drinking water meets state and federal standards and is safe to drink — would have been true regardless of what the testing found.

That’s because the contaminants that are present in Danville’s water — in the tiny concentrations that were found — haven’t been found to cause health problems in humans. If they had, the state and federal water regulations would have been changed, and the city — like water systems all over the state and nation — would have modified its filtration processes to screen them out.

The Dan River literally springs from the verdant terrain of Patrick County. It passes through Stokes and Rockingham counties in North Carolina and Pittsylvania County before it reaches Danville. At that point, the river’s water has minute traces of a chemical used in the making of polymers, an anticonvulsant and mood stabilizing drug, DEET, Prozac, a musk fragrance, a steroid hormone and an antibiotic.

Treated city water still has tiny amounts of the anticonvulsant and mood stabilizing drug, the musk fragrance and the steroid hormone. But for some reason, the treated water also contains byproducts of nicotine metabolism and caffeine metabolism, along with an antibiotic used in beef and dairy industries.

Those test results deserve some perspective. If the water had minute traces of aspirin in it, a person would have to drink a gallon of treated city water every day for between 580 years to 144,200 years to get one 80-milligram aspirin.

So while descriptions of the contaminants found sounds scary, the amounts are truly small.

Not all that long ago, drinking water contaminants were measured in parts per thousand. Have we reached the point where our ability to measure contaminants has fallen behind our knowledge about what, if any, effect those small concentrations have on human health?

The evolution of public water systems is the story of an ongoing struggle to make the water flowing from the tap as safe as possible. That’s why the recent testing for pharmaceuticals and cosmetic residues in drinking water should lead to even more studies about what constitutes safe drinking water.