The Stanford University researchers analyzed wells in the San Joaquin Valley and satellite imagery
A new study by Stanford University researchers, published in the journal Nature Communications, found that not only does groundwater pumping cause the ground to sink, it also increases arsenic levels in aquifers. The researchers found that satellite-derived measurements of ground sinking could predict arsenic concentrations in groundwater and that this method could be a potential warning system to anticipate future groundwater contamination, as reported by Science Daily.
“Arsenic in groundwater has been a problem for a really long time,” said Lead Author Ryan Smith. “But the idea that over pumping for irrigation could increase arsenic concentrations is new.”
The team analyzed arsenic data for hundreds of wells in drought periods, comparing estimates of land subsidence captured by satellites. Ultimately, they found that when land in the San Joaquin Valley’s Tulare basin sinks faster than 3 in. per year, the risk of arsenic groundwater contamination triples.
Notably, the study found that contaminated aquifers are capable of recovering if groundwater pumping is stopped or managed more efficiently.
“It’s definitely a big deal,” Smith told the San Francisco Chronicle. “This is a resource that a lot of people are relying on for their drinking water as well as their livelihoods through the economic value of the crops.”