Along some coastlines toxic contamination could seep into basements or broken sewage lines in coming years. In California's Bay Area, regulators are grappling with how to protect people.

Transcript

RACHEL MARTIN, HOST:

Maybe in your mind's eye, sea level rise looks like waves rolling ashore. What you may not imagine is the sea pushing water up from the ground beneath your feet. And in some places, that can bring toxic contamination. From member station KQED, Laura Klivans has the story.

LAURA KLIVANS, BYLINE: More than a century ago, industry in East Oakland, Calif., was booming, lumberyards, canneries, rail depots, foundries.

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UNIDENTIFIED NARRATOR: There are furnaces in which metal is heated and, under the masterful guidance of men, beaten into the 1,001 things needed.

KLIVANS: And workers lived nearby. Today, lots of people still live in East Oakland. Marquita Price stands on the porch of the one-story lavender house her grandma's owned for decades.

MARQUITA PRICE: What'd you tell me, though, when I would come down here?

UNIDENTIFIED PERSON: Stop jumping over that fence before you break your neck.

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KLIVANS: So when Price discovered that sea level rise from climate change could wreak slo-mo havoc on parts of this neighborhood, she worried.

PRICE: How is that going to affect my family, yes, and my community and the assets that we worked so hard to hold and, of course, our health?

KLIVANS: Price is an urban planner and learned about the threat while working on a project with Associate Professor Kristina Hill of UC Berkeley.

KRISTINA HILL: It's something that people haven't really thought of as an impactive, sea level rise.

KLIVANS: If you dig into the ground within a mile of the coast here, you'd first hit a layer of fresh water from rain. Below that, you'd find a layer of saltwater. The two layers mostly don't mix. That's because fresh water is lighter than saltwater and stays on top.

HILL: So it sits in the soil. And as the saltwater rises, that layer of fresh water will rise also.

KLIVANS: That rising water can bring up substances that have lingered for years underground.

HILL: Everything we've used in the last 150 years has, at some point, spilled.

KLIVANS: There's also contamination from leaks, benzene and toluene from underground storage tanks, for example. Many toxic sites are now considered to be contained, but not necessarily from underneath.

HILL: So legacy contamination in the soil will be remobilized when the water table comes up and intersects with these areas of contaminated soil.

KLIVANS: Alec Naugle leads the toxics cleanup division with California's water regulator. He's just beginning to think about how to protect people from these toxics.

ALEC NAUGLE: Now it's possible that you have contamination in that water. And you might not see it or smell it. You might not know.

KLIVANS: Naugle says that if these contaminants start to move, they could seep up into a basement or crawlspace beneath a home or sneak in through a broken sewage line. Some of these chemicals vaporize. And we can breathe them in.

NAUGLE: If you're exposed to these chemicals over a lifetime, it can increase your risk of cancer.

KLIVANS: Depending on how fast sea levels rise. Naugle says there's roughly 10 to 15 years before groundwater starts moving contaminants. Naugle and his team have to figure out which sites could pose a risk sooner than others.

NAUGLE: There are literally hundreds, perhaps, thousands of these cases in our region alone, not to mention statewide.

KLIVANS: Starting on solutions soon is key. That could mean inspecting and cleaning up sites that were once considered contained. Residents of East Oakland are no stranger to environmental hazards. They already live near major sources of pollution and have outsized rates of asthma. And now this, says Marquita Price.

PRICE: Things happen. You know, we can't prevent natural disasters or any kind of disasters or problems from happening.

KLIVANS: What she can do, Price says, is help tell her community about the threat of groundwater rise so people can do their best to plan for it.

For NPR News, I'm Laura Klivans in San Francisco.

(SOUNDBITE OF RRAREBEAR'S "BACKPACK") Transcript provided by NPR, Copyright NPR.