Could rising sea levels pollute fresh groundwater? Long Beach researchers are going to find out

Researchers from Cal State Long Beach and Cal State Northridge will kick off a two-year study starting on July 1 that will analyze how rising sea levels could cause underground fresh water to become contaminated with toxins further inland.

Their findings will then be used to create mapping tools to identify which low-income communities in California are most at risk of having their water contaminated in the near future. The goal is to bring awareness to state planners of the neighborhoods most impacted and how they can use the data to make better decisions when dealing with environmental planning.

Researchers Benjamin Hagedorn and Matt Becker of Cal State Long Beach and Danielle Bram of Cal State Northridge will begin the study by assessing just how vulnerable statewide groundwater currently is using existing datasets from the U.S. Geological Survey and other institutions.

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From there, they will take underground water samples of two disadvantaged coastal communities in California to analyze contaminants. Though the two communities have not been identified yet, Hagedorn said Long Beach could be selected as one of the study’s main focus communities.

As climate change prompts sea levels to rise, saltwater intrudes into areas where fresh groundwater is present, Hagedorn said. This process is called saltwater intrusion.

The saltwater then pushes fresh water closer to toxic spaces, such as underground septic tanks or soil contaminated with pesticides, which can lead to the water mixing with the contaminants.

A map from the California Water Resources Control Board shows that there are neighborhoods along the 710 freeway in West Long Beach that are located near contaminated clean-up zones. Hagedorn said there is a chance some of these clean-up sites have already been inundated by rising ground water, however, he has not seen official studies published to confirm.

“Often, this contamination stems from leaking underground storage tanks from gas stations, dry cleaners, chemical industries,” Hagedorn said. “There are many of those in Long Beach. The goal of our project is to evaluate the risk of a rising groundwater table inundating these sites.”

The situation is dire, Hagedorn said, as clean, fresh groundwater is both expensive to maintain and quickly becoming a commodity. The research proposal was awarded over $200,000 in grant money to complete the study. It was selected as one out of three other projects to be awarded grants from the California State University Council on Ocean Affairs, Science and Technology.

“It’s important that we understand our resources before we destroy them,” Hagedorn said. “We are running out of options. Freshwater is becoming more valuable, and we have to protect it from unnecessary contamination.”

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