California is about to enter its dry season following one of its driest winters in history. It was preceded by a brief respite from the worst drought it has ever experienced. No wonder water managers in the Central Valley’s parched farm belt are increasingly interested in a controversial practice: reusing oil field wastewater to grow crops.
The Central Valley Regional Water Quality Control Board assured critics last fall that it had conducted studies on the practice and found no high-risk situations for human health or crop safety. The board focused primarily on one question—are crops grown with produced water safe to eat?—and considered as beyond the scope of its responsibility the wider range of potential harms associated with recycling the oil industry’s wastewater.
The board acknowledged that it did not study how long-term use of oil companies’ “produced water” might affect crops and soil that are irrigated with it, or whether toxic chemicals in the wastewater could accumulate over time in the nuts, oranges and grapes that are sent around the world. The board did not consider the ecological consequences of spreading oilfield wastewater across land in a county that contains at least 20 endangered or threatened species. This is a close proximity that has already led to millions of gallons inundating their habitat.
Scientists from other parts of the country are investigating these questions. They examine the effects of oil wastewater being used for irrigation and disposed off, as well the potential impacts on wildlife. Research is showing that even highly diluted oil water can damage soil, plants, aquatic life. A recent analysis by Inside Climate News found that oil drilling can increase groundwater levels of naturally occurring toxic elements, such as arsenic, radioactive elements, like radium, and also endanger sensitive ecosystems and wildlife.
Over the years, research has shown that produced water can reduce crop yields, suppress plant disease defenses, inhibit seed vigor or germination, impair soil health and reduce microbial diversity. It can also harm fish and other amphibians. Scientists have also seen the accumulation of toxic chemicals and metals in the roots, shoots, and stems of wheat plants.
None of these studies were done in Kern County. But scientists who have conducted, or reviewed, the findings said there’s enough evidence to proceed with caution in California.
“There are a number of studies available now that can help guide what precautions we ought to take and what contaminants we might expect could be persistent or show up,” said Isabelle Cozzarelli, a research hydrologist with the U.S. Geological Survey who has studied the environmental impacts of oil and gas contaminants in several Eastern and Midwest states. “We know enough to know we better be careful.”
Kern County has been struggling for years to support thirsty crops such as almonds and pistachios. The county receives less than 10 inches of rain per year. And with climate change, hopes of a “normal” year are disappearing faster than the Sierra Nevada snowpack needed to replenish the state’s water supplies.
But as it gets harder and harder to extract California’s tarry crude oil from aging wells, the massive stream of wastewater keeps increasing.
Over the past 20 years, the ratio of wastewater produced to oil extracted has more then doubled. And Chevron’s sale of produced water to Kern County’s Cawelo Water District increased from an average of 19,000 acre-feet—or about 6 billion gallons—in the mid-1990s to nearly 30,000 acre-feet, or nearly 10 billion gallons, in recent years, as regulators restricted groundwater pumping and surface water allocations evaporated with the drought.
The Central Valley Water Board, which oversees Cawelo, and other water districts in the area, approved two applications to expand irrigation water use in 2019. They are currently reviewing another.
More than 14 billion gallons of produced water from Chevron and a handful of other Kern County oil companies now saturate nearly 100,000 acres, about 11 percent of the county’s irrigated farmland.
Irrigation districts that supply the region’s multibillion dollar agricultural industry view produced water as a way to cope with its perpetual water woes. Public interest groups, on the other hand, have pressured state officials to stop growing food with manufactured water, citing potential risks to the environment, wildlife, and people.
The Central Valley Water Board responded to the public concern by launching a Food Safety Project in 2015, and retained a firm it described as a “neutral third party” to study potential risks of the practice. GSI Environmental had a long history working in the oil industry, including Chevron which is the largest supplier of water for farmers.
The board’s review of GSI’s studies noted that chemicals in produced water used for irrigation had the potential to accumulate in crops and soil, said Clay Rodgers, who oversaw the Food Safety Project. Although the studies did not yield “significant differences” that could be attributed to produced water in the crops that were tested, he said, “There is an unknown potential that chemicals from produced water and other environmental sources may be accumulating in the soil.”
The water board is not proposing additional studies to close these data gaps, Rodgers said, “as funding is not available.”
Madalyn Blondes (a research geologist at the USGS) said that scientists from the agency are looking into the possibilities of reusing industrial waste, such as produced waters, in drought-prone regions. “If we can do it safely, then we should look into those options.”
She added, “But it’s important to look at what potential impacts are and actually analyze where there might be certain unintended effects.”
“It’s not just a matter of saying everything’s fine, let’s do it,” Blondes said.
For decades, San Joaquin Valley farmers enjoyed unfettered access to the state’s aquifers, severely depleting groundwater supplies to cope with droughts.
Former state Sen. Fran Pavley (D-Agoura Hills) put an end to unregulated pumping in 2014, when she helped pass California’s Sustainable Groundwater Management Act, or SGMA.
But now, Kern water districts are promoting the wastewater of an industry that has contaminated the state’s dwindling groundwater reserves as a resource that instead conserves them.
Pavley was also the author of the first law that required oil companies to report how much water and what chemicals they added to fracked wells. This approach is contrary to the law’s intent.
California’s water is in critically short supply, said Pavley, now the environmental policy director for the University of Southern California’s Schwarzenegger Institute. “We need to make sure we’re not contaminating the water we have and affecting the health and safety of people and the agricultural crops people digest.”
Water districts often mix ground and surface water to produce water before sending it out to farmers for irrigation. Kern County is one of the few regions in the country where produced water has low enough saline levels that even lightly blended water doesn’t kill crops outright. That’s partly because seasonal runoff from melting Sierra snowpack recharges the groundwater and dilutes toxic salts.
Climate models show that the salinity of Kern County’s water sources is likely to increase as the planet heats. That’s because county aquifers will see less seasonal influx of freshwater from the mountains as rising global temperatures evaporate more water and keep Sierra snowpack levels low.
Rodgers stated that the effects of oil field wastewater on soils and plants in California are primarily due salinity, which is not an issue for Kern.
Recent studies have shown, however, that salt compounds aren’t the only contaminants that can affect soil and plant health.
In 2019, researchers reported the first evidence that produced water can impair plant defenses against pathogens in the peer-reviewed journal Environmental Science & Technology Letters.
The researchers suspected that it wasn’t salinity that was primarily responsible for weakening the immune responses of wheat plants, but possibly boron and petroleum hydrocarbons. Both contaminants are common in Kern County’s produced water.
And though California still has lower salinity than other groundwater basins USGS scientists have studied, said Blondes, “that doesn’t mean it can’t have high concentrations of other compounds.”
She added that even when compounds are present in low levels, if enough compounds belong to a similar class, they could be combined to prove dangerous.
And it’s naturally occurring toxic elements like cancer-causing radium and arsenic left behind in groundwater and surface water by oil extraction that are most concerning to Blondes. “Everyone talks about the risks of fracking fluids,” she said. “But there are lots of naturally occurring chemicals that aren’t additives that have all kinds of environmental and health impacts.”
Drowning in Oil Waste
The environment and wildlife are at risk from oil-drilling techniques that produce water for irrigation.
To coax Kern’s heavy crude to the surface, oil companies inject high-pressure steam and water into wells. This technique uses so much pressure that, in the county’s highly developed oil fields, it can accidentally force oil and wastewater to burst out through fissures in the earth, causing above-ground spills called “surface expressions.”
Surface expressions weren’t explicitly banned in California until April 2019.
About a month after the state regulated these inland spills, oil and wastewater escaped from wells at Chevron’s Cymric Oil Field, some 140 miles north of Los Angeles. Over four months, more than 1.3 million gallons hot oil and water, including 400,000 crude oil, gushed from the earth, turning a dry streambed to a river oily wastewater.
Officials from the Wildlife Department found four birds that were covered in oil, but could not save them. State records show that Chevron made nearly $400,000 selling oil from the spillage.
California fined Chevron more than $2.7 million for numerous violations, noting that the spills caused “significant threat of harm to human health and the environment.”
Crews were barely able to clean up the massive spillage, one of California’s largest ever, when hundreds of thousands gallons of oily water seeped through the ground in another section in the same oil field. According to state records, more than 5 million gallons worth of gooey water from these eruptions have reached the surface at a nearby site since May 13.
These types of practices endanger people and wildlife, said Hollin Kretzmann, senior attorney with the Center for Biological Diversity’s Climate Law Institute, “but the company hasn’t paid a dime of that $2.7 million fine.”
Chevron representatives said they’ve been working with regulators to resolve the issue.
Sean Comey, senior communications advisor with Chevron’s San Joaquin Valley division, said in an email that Chevron had submitted reports of soil studies and remediation activities to the Central Valley Water Board. “The parties are making progress and continue to engage in good-faith efforts to reach a resolution,” he said.
CalGEM, the agency that regulates oil and gas, did not respond to repeated requests for comment about how the state planned to resolve Chevron’s case.
Aera Energy, a joint venture between Shell and ExxonMobil in 2020, applied for a U.S. The Endangered Species act exempts companies from prosecution for operations that harm or kill species. A Fish and Wildlife Service permit was obtained by Aera Energy. Aera’s application for an “incidental take” permit seeks protection if current or expanded oil operations over the next 35 years harm any of five protected species: the San Joaquin kit fox, blunt-nosed leopard lizard, San Joaquin antelope squirrel and giant kangaroo rat.
The Center for Biological Diversity has filed comments with USFWS opposing Aera’s application, which is still under review, arguing that climate change is already increasing species extinction risk by disrupting ecosystems. “Any expanded oil operations are inherently incompatible to species protection,” the group said.
“Kern County is smack dab in the middle of a really biodiverse San Joaquin Valley,” said Kretzmann. Aera’s application “is essentially an admission that, ‘Yeah, our oil and gas operations are going to affect these species.’”
Multiple requests for comment were not answered by Aera.
Kern County valleys, where lakes, wetlands, and saltbush scrublands once dominated, have been demolished by intensive oil production.
An ecological risk assessment is warranted, said Andrew Gordus, a California Department of Fish and Wildlife toxicologist who served on the water board’s expert panel. “But someone has to come up with the funding to do such a study.”
The water board study of wastewater irrigation, said Gordus, who retired last year, had a much narrower focus: “Is the edible part of the plant safe to eat?”
A minimum of 20 endangered or threatened species live within a mile radius from a Kern County oilfield, where pump jacks sucking up oil 24 hours a day. There are very few peer reviewed studies that have looked into the ecological impacts of oil operations.
Many endangered species have been decimated by oil waste. Over the years, scientists have found endangered blunt-nosed leopard lizards, San Joaquin kit foxes and giant kangaroo rats, one of the foxes’ primary prey, drowned in oil spills and oil wastewater. All three species can be found in California.
Independent studies have not yet revealed how native wildlife and plants cope with the millions upon millions of gallons hot water and oil that inundate their habitats.
More questions than answers
Scientists still don’t know enough about the environmental and health effects of growing crops using produced water. However, they have gleaned some clues from investigating spillages such as the one at Cymric. Cozzarelli from the USGS studies has studied spills, disposal of produced water, and the potential risks associated with intentional reuse.
In a 2016 study of a West Virginia produced water disposal facility, Cozzarelli’s team found concentrations of radioactive elements and other toxics in a nearby stream. The toxic chemicals reduced microbial diversity, signaling effects on the freshwater ecosystem, they reported in Environmental Science & Technology. A similar study revealed that stream water disrupted many hormones in lab testing, raising concerns about wildlife health and the potential for people to become sick from drinking water.
But the disposal facility cut off the team’s access halfway through the study, Cozzarelli said, “once we started to find out that there were some negative environmental effects.”
Scientists from the USGS have had better luck at a county site near Bemidji in Minnesota. This is where a high pressure pipeline burst open in 1979 and spilled nearly 450,000 gallons crude oil. They’ve had decades of uninterrupted access because the site is on public land. They also studied the effects of spills of water on federal land.
Numerous studies have shown that hydrocarbons in crude oil, which release greenhouse gases when they are burned, can harm aquatic ecosystems. Cozzarelli also stated that research on produced water spillages has shown that chloride, as well as other naturally occurring elements, have been particularly harmful to soil and plants.
Rodgers of the water board said concerns about harmful effects to aquatic life are not relevant because Kern’s produced water isn’t discharged into streams.
Cozzarelli stated that little is known about how oil and gas wastewater contaminants move from the fields into streams and other surfaces waters. Monitoring runoff from irrigated fields is particularly important for substances that don’t easily break down and have toxic effects, she said.
The same elements found to harm aquatic species taint Kern County’s produced water, as do the hydrocarbons in petroleum. Cozzarelli published in a peer reviewed study in 2015 that crude oil can contain arsenic. This is because groundwater chemistry is affected by hydrocarbons in crude.
Arsenic exposure can lead to many diseases, including liver disease and cancer. Cozzarelli’s team discovered that the arsenic levels found in the contaminated groundwater of Bemidji were 23-times higher than the drinking water standards. When hydrocarbons are introduced to groundwater, they cause reactions with compounds found in sediments to release additional arsenic.
Both the upper Midwest and Kern County have high arsenic levels in groundwater, Cozzarelli said, “just from natural organic material that’s degrading.”
Oil extraction accelerates that process “by dumping in a whole bunch more” rapidly biodegradable hydrocarbons, she said. Petroleum not only releases more arsenic to groundwater, but also trace metals such as cadmium and copper.
USGS studies of both intentional reuse and spills reveal that even low levels of toxic compounds in water and soil can build up and move across the landscape—and why studying soil irrigated with produced water is so important.
Bonnie McDevitt, a USGS postdoctoral researcher, spent many years studying a Wyoming site where water is released into streams for irrigation and livestock drinking. The produced water had low salinity, like Kern County’s.
She emphasized radioactive element radium. Although the radiation at the discharge site was below the levels allowed by federal regulations, she reported in a 2019 peer reviewed study that it had accumulated in sediments downstream at much higher levels.
McDevitt also saw “significant uptake” in wetland plants, particularly cattails. She said she didn’t do any studies on irrigated crops and is unsure if any have been done. “But small discharges of radium can still accumulate,” she said.
The Central Valley Water Board concluded that radioactive elements in produced water were unlikely to pose a risk, based on a review of its consulting firm’s studies. “Although GSI did not evaluate the potential for radionuclides to accumulate in the water distribution system, GSI did conclude that radionuclides do not appear to be a health risk in irrigated crops,” the board said in response to a public comment.
McDevitt said that she would approach this conclusion with caution in an arid area where evaporation might be a possibility. Concentrations that appear safe at one point in a water system could prove hazardous miles downstream, she said, “where you have almost 100 percent evaporation.”
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That’s exactly what happens during drought, when salts and other harmful compounds are likely to accumulate, said Cozzarelli. “Even if the concentration in the applied water didn’t seem concerningly high, it could accumulate to levels that affect soil health.”
Oil wastewater is “loaded with things we need to be concerned about,” she said, pointing to the carcinogens benzene and arsenic. These toxic substances can remain in groundwater for years if they are allowed to.
Contaminated sediments are like a leaky storage box, releasing their toxic contents as water levels rise.
When Cozzarelli studied a spill in North Dakota’s Blacktail Creek, she found that contaminated water infiltrated riverbanks during high flow, then escaped during low flow. She stated that the study showed that both contaminated soil and contaminated water can be stored in soil pores over long periods.
Flooding can also spread toxic compounds across the landscape.
Cozzarelli explained that there was a lot more radium on Blacktail Creek’s floodplain because of a heavy flood that brought sediment from the river channel.
Floods could wash away toxic compounds that have built up in the soil from fields irrigated in Kern County with produced water. California is in yet another multiyear drought. However, climate models predict that extreme precipitation could follow exceptionally dry years. And when it does, Kern County faces “relatively high” risk of flooding, according to FEMA.
With “thousands of things in these produced waters,” Cozzarelli said, scientists have started to focus on evaluating how the water itself rather than individual chemicals affect organisms and ecosystems.
But this is just the beginning.
“We do more studies, we answer a few questions, and then it brings up so many more questions,” Cozzarelli said.
Pavley, who is known for her pioneering climate legislation and questions about the environmental and health hazards of produced water distracts from the true goal: weaning from oil and gas.
“You wouldn’t have oil field wastewater,” she said, “if you didn’t have oil fields.”
Source: Inside Climate News