Whelton, the environmental engineer at Purdue, would have preferred immediate warnings against showering and bathing, particularly since one San Lorenzo Valley neighborhood had 42 times more benzene than state limits allow.
Chemical levels dropped below the state’s standard after the pipes were flushed, Newton said. But Whelton said that testing after wildfires should continue for long periods, and should be expanded to more chemicals.
He also worries that the failure to rapidly warn people against bathing in potentially contaminated water led to precisely the predicament Petrini found himself in when weighing how to wash baby Levi.
“You have to issue water advisories and orders that don’t allow infants and children to be exposed to contaminated water,” Whelton said. “This isn’t complicated. After a disaster, the infrastructure may be damaged, you issue a ‘do not use’ order.”
Stefan Cajina, north coastal section chief of the water board’s drinking water division, said that drinking water officials usually reserve issuing stricter guidance around showering and bathing for when they know for certain the water is contaminated. But “that has turned out to be a really confusing and uncomfortable message for the public to hear,” Cajina said.
Now the state is considering reversing that approach to recommend water systems start with more stringent cautions, and scale them back as test results show the water is safe.
“Bottom line, water systems may want to be told what to do in these situations, and we do our best to provide solid guidance, but they are ultimately responsible,” he said.
When the fires stop, the rains start
As California heads into the rainy season, the threats to drinking water will be amplified. Rains may extinguish wildfires, but they can also wash contaminants into water sources.
“Really what’s going to determine how ugly things get and how concerning they get for both the health of our ecosystems and for our communities are those first rain events that we’re going to get this fall, and really the first couple of years,” Oregon State University’s Bladon said. Particularly if vegetation hasn’t had a chance to regrow on slopes scoured by wildfires.
Fires kill plants, increasing runoff and accelerating snowmelt. Burning soil can also change its structure, trigger erosion and leave behind layers of ash and debris that flow into streams and lakes.
“Every drop of water in a watershed basically is moving towards that outlet,” said Newsha Ajami, director of Urban Water Policy at Stanford University. “And if they’re not cleaned up, all those pollutants and contaminants and toxins can end up in our water system.”
Sediment slicking down fire-denuded hills can fill reservoirs, squeezing out space for the water. In Santa Barbara County, the Gibraltar Reservoir has lost roughly 50% of its storage capacity over the past 20 years, largely due to increased sedimentation from wildfires, according to Joshua Haggmark, Santa Barbara’s water resources manager.
After the 2007 Zaca Fire, the organic material clouding Cachuma Lake jumped by 165%. And it still hasn’t returned to historic lows, Haggmark said. Near Redding, water from Whiskeytown Lake grew roughly 20 times dirtier after the Carr Fire.
All that material can challenge downstream treatment plants to cope with the added mud and altered water chemistry, and it may fuel algal blooms. But adding chlorine to treat the water can kick off chemical reactions with all the additional organic matter to form disinfection byproducts linked to health problems, including bladder cancer.
More of the ingredients that form these disinfection byproducts were found in Northern California creeks after the Rocky and Wragg fires burned through the region in 2015, according to a recent study.
In Napa County, Silke has encountered increased sediment repeatedly in Lake Berryessa after previous wildfires, and he’s bracing for problems at the treatment plant in the months ahead.
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Unsafe to drink: Wildfires threaten rural towns with tainted water - The Counter
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