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California sets nation’s first water standard for cancer-causing contaminant

News Feed
Wednesday, April 17, 2024

In summary Water suppliers say the costs will be massive, with rates increasing for many consumers. Known as the “Erin Brockovich” chemical, hexavalent chromium is found statewide. In an effort to protect more than 5 million Californians from a cancer-causing contaminant, state regulators today set a new standard that is expected to increase the cost of water for many people throughout the state.  The State Water Resources Control Board unanimously approved the nation’s first drinking water standard for hexavalent chromium, which is found naturally in some California groundwater as well as water contaminated by industries. Now water suppliers will be forced to install costly treatment to limit the chemical in water to no more than 10 parts per billion — equivalent to about 10 drops in an Olympic-sized swimming pool.  California water systems are expected to spend $180 million a year to comply, including testing and treatment. The water board said the average cost for most people would be less than $20 per month, with 87% paying about $8 per month. The cost rises an average of $135 per month for people served by water agencies with fewer than 100 connections.  Water suppliers warned officials that the costs of complying would hit low-income customers especially hard.  Coachella City Councilman Frank Figueroa said it would cost his city $90 million to install treatment on its wells, which would increase average monthly bills by almost 500% — “an insufferable figure” for the community, where incomes average $24,000 a year per person. Cities and water agencies said they desperately need financial help from the state. “This year’s fiscal crunch does not bode well, and even in a good year, they (state officials) can’t get aid to everyone that needs it,” Tim Worley, managing director of the Community Water Systems Alliance, told CalMatters.  Hexavalent chromium was made infamous by the movie “Erin Brockovich,” which dramatized Pacific Gas & Electric’s contamination of the water supply of a small California desert town. PG&E paid a $333 million settlement to about 600 Hinkley residents in 1996 who claimed they suffered high rates of cancer and other diseases. Levels above the new state limit have been reported in about 330 sources of water supplies in California. Some of the areas affected are the counties of Sacramento, Solano, Santa Cruz, San Bernardino, Santa Barbara, Monterey and Merced. The highest levels found were in Riverside, Yolo, Los Angeles and Ventura counties, although water suppliers may blend or treat the water to reduce the contaminants there. Central Coast resident Ana Maria Perez told the board that her community suffers from elevated levels of hexavalent chromium, nitrates and other contaminants.  “I’m here because the State Water Board has again failed us,” she said through an interpreter. “It’s not fair that many people have to get sick and even die because the State Water Board has not done their job well.” The largest water suppliers will have two years to comply; smaller ones with fewer than 1,000 connections will have four years. Many water suppliers said permitting, financing and construction timelines would make it difficult to meet these deadlines, and urged the state for more flexibility.  “It’s untenable for some of those communities,” said Andrea Abergel, manager of water policy for the California Municipal Utilities Association.  The new standard is one of the least protective of all the water contaminants regulated by California, according to a state analysis.  Public health advocates had urged a more stringent standard because the one set is 500 times higher than the level that state scientists deemed a negligible, one-in-a-million cancer risk. Under the new standard, for every 2,000 people who drink the water for a lifetime, one person would be at risk of cancer.   “Personally, I think we should go lower,” said water board member Laurel Firestone. She voted for it anyway but wants to revisit it when the standard is reviewed in five years.  Max Costa, professor and chair of environmental medicine at NYU School of Medicine, was an expert witness for residents in the Brockovich case. When California regulators first unveiled the proposed limit, he said “it’s not terrible, but it’s not acceptable…The most acceptable level is none.”  Some hexavalent chromium occurs naturally in California’s rocks and soils; some seeps into the environment from industries that work with chrome, such as metal-plating, stainless steel production and wood preservation.  California’s new standard is “expected to protect an estimated 5.5 million people… from potential illness due to hexavalent chromium,” according to a water board report.  California until now limited hexavalent chromium under a combined standard of 50 parts per billion for all types of chromium, including a more benign type called trivalent chromium. The U.S. Environmental Protection Agency doesn’t have a hexavalent chromium standard for drinking water. Instead, more than 30 years ago, it set a national standard for total chromium at 100 parts per billion, or 10 times higher than the California one for hexavalent chromium. In response to studies linking it to cancer, the EPA is now conducting a human health risk assessment for the contaminant. A decade ago, California regulators tried to enact the same limit for hexavalent chromium but the regulation was overturned in court because it “failed to properly consider the economic feasibility of complying.”  California regulators said their analysis now supports the feasibility because of the low per-person costs for most people and “because there are sufficient resources available.” They added, though, that they can’t guarantee state funding to assist water suppliers. “Those same dollars are spoken for time and time again,” water board member Sean Maguire said at the hearing today. “Which is why we have so many folks who still are struggling meeting even the current standards that we have today.”  Hexavalent chromium has long been known to cause cancer when it’s inhaled, but until recently it was controversial whether drinking it also was linked to cancer. In 2008, s study showed that rats and mice drinking high doses grew cancers in their mouths and intestines, which scientists say "clearly demonstrates” a cancer risk from consuming it. Roberta Walker, a former resident of Hinkley, blames the contaminant for health problems that have plagued her family and community. The levels of contamination in Hinkley were far higher than the limits the state adopted today. But even California’s new limits, Walker said, are too high.  “I don’t care if it’s a pinch or a lot. A poison is poison,” Walker said. “No matter how you look at it, it’s not good.” 

Water suppliers say the costs will be massive, with rates increasing for many consumers. Known as the “Erin Brockovich” chemical, hexavalent chromium is found statewide.

In summary

Water suppliers say the costs will be massive, with rates increasing for many consumers. Known as the “Erin Brockovich” chemical, hexavalent chromium is found statewide.

In an effort to protect more than 5 million Californians from a cancer-causing contaminant, state regulators today set a new standard that is expected to increase the cost of water for many people throughout the state. 

The State Water Resources Control Board unanimously approved the nation’s first drinking water standard for hexavalent chromium, which is found naturally in some California groundwater as well as water contaminated by industries.

Now water suppliers will be forced to install costly treatment to limit the chemical in water to no more than 10 parts per billion — equivalent to about 10 drops in an Olympic-sized swimming pool

California water systems are expected to spend $180 million a year to comply, including testing and treatment. The water board said the average cost for most people would be less than $20 per month, with 87% paying about $8 per month. The cost rises an average of $135 per month for people served by water agencies with fewer than 100 connections. 

Water suppliers warned officials that the costs of complying would hit low-income customers especially hard. 

Coachella City Councilman Frank Figueroa said it would cost his city $90 million to install treatment on its wells, which would increase average monthly bills by almost 500% — “an insufferable figure” for the community, where incomes average $24,000 a year per person.

Cities and water agencies said they desperately need financial help from the state.

“This year’s fiscal crunch does not bode well, and even in a good year, they (state officials) can’t get aid to everyone that needs it,” Tim Worley, managing director of the Community Water Systems Alliance, told CalMatters. 

Hexavalent chromium was made infamous by the movie “Erin Brockovich,” which dramatized Pacific Gas & Electric’s contamination of the water supply of a small California desert town. PG&E paid a $333 million settlement to about 600 Hinkley residents in 1996 who claimed they suffered high rates of cancer and other diseases.

Levels above the new state limit have been reported in about 330 sources of water supplies in California. Some of the areas affected are the counties of Sacramento, Solano, Santa Cruz, San Bernardino, Santa Barbara, Monterey and Merced. The highest levels found were in Riverside, Yolo, Los Angeles and Ventura counties, although water suppliers may blend or treat the water to reduce the contaminants there.

Central Coast resident Ana Maria Perez told the board that her community suffers from elevated levels of hexavalent chromium, nitrates and other contaminants. 

“I’m here because the State Water Board has again failed us,” she said through an interpreter. “It’s not fair that many people have to get sick and even die because the State Water Board has not done their job well.”

The largest water suppliers will have two years to comply; smaller ones with fewer than 1,000 connections will have four years. Many water suppliers said permitting, financing and construction timelines would make it difficult to meet these deadlines, and urged the state for more flexibility. 

“It’s untenable for some of those communities,” said Andrea Abergel, manager of water policy for the California Municipal Utilities Association. 

The new standard is one of the least protective of all the water contaminants regulated by California, according to a state analysis. 

Public health advocates had urged a more stringent standard because the one set is 500 times higher than the level that state scientists deemed a negligible, one-in-a-million cancer risk. Under the new standard, for every 2,000 people who drink the water for a lifetime, one person would be at risk of cancer.  

“Personally, I think we should go lower,” said water board member Laurel Firestone. She voted for it anyway but wants to revisit it when the standard is reviewed in five years. 

Max Costa, professor and chair of environmental medicine at NYU School of Medicine, was an expert witness for residents in the Brockovich case. When California regulators first unveiled the proposed limit, he said “it’s not terrible, but it’s not acceptable…The most acceptable level is none.” 

Some hexavalent chromium occurs naturally in California’s rocks and soils; some seeps into the environment from industries that work with chrome, such as metal-plating, stainless steel production and wood preservation. 

California’s new standard is “expected to protect an estimated 5.5 million people… from potential illness due to hexavalent chromium,” according to a water board report. 

California until now limited hexavalent chromium under a combined standard of 50 parts per billion for all types of chromium, including a more benign type called trivalent chromium.

The U.S. Environmental Protection Agency doesn’t have a hexavalent chromium standard for drinking water. Instead, more than 30 years ago, it set a national standard for total chromium at 100 parts per billion, or 10 times higher than the California one for hexavalent chromium. In response to studies linking it to cancer, the EPA is now conducting a human health risk assessment for the contaminant.

A decade ago, California regulators tried to enact the same limit for hexavalent chromium but the regulation was overturned in court because it “failed to properly consider the economic feasibility of complying.” 

California regulators said their analysis now supports the feasibility because of the low per-person costs for most people and “because there are sufficient resources available.” They added, though, that they can’t guarantee state funding to assist water suppliers.

“Those same dollars are spoken for time and time again,” water board member Sean Maguire said at the hearing today. “Which is why we have so many folks who still are struggling meeting even the current standards that we have today.” 

Hexavalent chromium has long been known to cause cancer when it’s inhaled, but until recently it was controversial whether drinking it also was linked to cancer. In 2008, s study showed that rats and mice drinking high doses grew cancers in their mouths and intestines, which scientists say "clearly demonstrates” a cancer risk from consuming it.

Roberta Walker, a former resident of Hinkley, blames the contaminant for health problems that have plagued her family and community. The levels of contamination in Hinkley were far higher than the limits the state adopted today. But even California’s new limits, Walker said, are too high. 

“I don’t care if it’s a pinch or a lot. A poison is poison,” Walker said. “No matter how you look at it, it’s not good.” 

Read the full story here.
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California cities pay a lot for water; some agricultural districts get it for free

Even among experts the cost of water supplies is hard to pin down. A new study reveals huge differences in what water suppliers for cities and farms pay for water from rivers and reservoirs in California, Arizona and Nevada.

In summary Even among experts the cost of water supplies is hard to pin down. A new study reveals huge differences in what water suppliers for cities and farms pay for water from rivers and reservoirs in California, Arizona and Nevada. California cities pay far more for water on average than districts that supply farms — with some urban water agencies shelling out more than $2,500 per acre-foot of surface water, and some irrigation districts paying nothing, according to new research.  A report published today by researchers with the UCLA Institute of the Environment and Sustainability and advocates with the Natural Resources Defense Council shines a light on vast disparities in the price of water across California, Arizona and Nevada.  The true price of water is often hidden from consumers. A household bill may reflect suppliers’ costs to build conduits and pump water from reservoirs and rivers to farms and cities. A local district may obtain water from multiple sources at different costs. Even experts have trouble deciphering how much water suppliers pay for the water itself. The research team spent a year scouring state and federal contracts, financial reports and agency records to assemble a dataset of water purchases, transfers and contracts to acquire water from rivers and reservoirs. They compared vastly different water suppliers with different needs and geographies, purchasing water from delivery systems built at different times and paid for under different contracts. Their overarching conclusion: One of the West’s most valuable resources has no consistent valuation – and sometimes costs nothing at all.  Cities pay the highest prices for water. Look up what cities or irrigation districts in California, Nevada and Arizona pay for surface water in our interactive database at calmatters.org “It costs money to move water around,” the report says, “but there is no cost, and no price signal, for the actual water.” That’s a problem, the authors argue, as California and six other states in the Colorado River basin hash out how to distribute the river’s dwindling flows — pressed by federal ultimatums, and dire conditions in the river’s two major reservoirs. The study sounds the alarm that the price of water doesn’t reflect its growing scarcity and disincentivizes conservation. “We’re dealing with a river system and water supply source that is in absolute crisis and is facing massive shortfalls … and yet we’re still treating this as if it’s an abundant, limitless resource that should be free,” said Noah Garrison, environmental science practicum director at UCLA and lead author on the study.  Jeffrey Mount, senior fellow at the Public Policy Institute of California, applauded the research effort. Though he had not yet reviewed the report, he said complications abound, built into California’s water infrastructure itself and amplified by climate change. Moving, storing and treating water can drive up costs, and are only sometimes captured in the price.  “We’ve got to be careful about pointing our fingers and saying farmers are getting a free ride,” Mount said. Still, he agreed that water is undervalued: “We do not pay the full costs of water — the full social, full economic and the full environmental costs of water.”  Coastal cities pay the most The research team investigated how much suppliers above a certain purchase threshold spend on water from rivers and reservoirs in California, Arizona and Nevada.  They found that California water suppliers pay more than double on average than what Nevada districts pay for water, and seven times more than suppliers in Arizona.  The highest costs span the coast between San Francisco and San Diego, which the researchers attributed to the cost of delivery to these regions and water transfers that drive up the price every time water changes hands.  “In some of those cases it’s almost a geographic penalty for California, that there are larger conveyance or transport and infrastructure needs, depending on where the districts are located,” Garrison said.  Agricultural water districts pay the least In California, according to the authors, cities pay on average 20 times more than water suppliers for farms — about $722 per acre foot, compared to $36.  One acre foot can supply roughly 11 Californians for a year, according to the state’s Department of Water Resources.  Five major agricultural suppliers paid nothing to the federal government for nearly 4 million acre-feet of water, including three in California that receive Colorado River water: the Imperial Irrigation District, the Coachella Valley Water District and the Palo Verde Irrigation District.  Tina Anderholt Shields, water manager for the Imperial Irrigation District, which receives the single largest share of Colorado River water, said the district’s contract with the U.S. government does not require any payment for the water.  Cities, by contrast, received less than 40,000 acre-feet of water for $0. The report notes, however, that the Metropolitan Water District of Southern California, a major urban water importer, spends only 25 cents an acre-foot for around 850,000 acre-feet of water from the Colorado River.  Bill Hasencamp, manager of Colorado River resources at Metropolitan, said that the true cost of this water isn’t reflected in the 25-cent fee, because the expense comes from moving it. By the time the Colorado River water gets to the district, he said it costs several hundred dollars. Plus, he added, the district pays for hydropower, which helps cover the costs of the dams storing the water supply. “That enables us to only pay 25 cents an acre foot to the feds on the water side, because we’re paying Hoover Dam costs on the power side.” Federal supplies are the cheapest; transfers drive up costs Much of the difference among water prices across three states comes down to source: those whose supplies come from federally managed rivers, reservoirs, aqueducts and pumps pay far less on average than those receiving water from state managed distribution systems or via water transfers.  Garrison and his team proposed adding a $50 surcharge per acre-foot of cheap federal supplies to help shore up the infrastructure against leaks and losses or pay for large-scale conservation efforts without tapping into taxpayer dollars.  But growers say that would devastate farming in California.  “It’s important to note that the ‘value’ of water is priceless,” said Allison Febbo, General Manager of Westlands Water District, which supplies San Joaquin Valley farms. The report calculates that the district pays less than $40 per acre foot for water from the federal Central Valley Project, though the Westlands rate structure notes another $14 fee to a restoration fund. “The consequences of unaffordable water can be seen throughout our District: fallowed fields, unemployment, decline in food production…” The Imperial Irrigation District’s Shields said that a surcharge would be inconsistent with their contract, difficult to implement, and unworkable for growers.  “It’s not like farmers can just pass it on to their buyers and then have that roll down to the consumer level where it might be ‘manageable,’” Shields said. The most expensive water in California is more than $2,800 an acre-foot The most expensive water in California, Arizona or Nevada flows from the rivers of Northern California, down California’s state-managed system of aqueducts and pumps, to the San Gorgonio Pass Water Agency in Riverside County. Total cost, according to the report: $2,870.21 per acre foot.  Lance Eckhart, the agency’s general manager, said he hadn’t spoken to the study’s authors but that the number sounded plausible. The price tag would make sense, he said, if it included contributing to the costs for building and maintaining the 705-mile long water delivery system, as well as for the electricity needed to pump water over mountains.  Eckhart compared the water conveyance to a railroad, and his water agency to a distant, distant stop. “We’re at the end, so we have the most railroad track to pay for, and also the most energy costs to get it down here,” he said.  Because it took decades for construction of the water delivery system to reach San Gorgonio Pass, the water agency built some of those costs into local property taxes before the water even arrived, rather than into the water bills for the cities and towns they supply. As a result, its mostly municipal customers pay only $399 per acre foot, Eckhart said.  “You can’t build it into rates if you’re not going to see your first gallon for 40 years,” Ekhart said.  The study didn’t interrogate how the wholesale price of imported water translates to residential bills. Water managers point out that cheap supplies like groundwater can help dilute the costs of pricey imported water.  The Los Angeles Department of Water and Power, for instance, purchases water imported from the Colorado River and Northern California to fill gaps left by local groundwater stores, supplies from the Owens Valley, and other locally managed sources, said Marty Adams, the utility’s former general manager. (The Los Angeles Department of Water and Power was unable to provide an interview.) Because the amount of water needed can vary from year to year, it’s added as an additional charge on top of the base rate, Adams said. “If you have to pay for purchased water somewhere, when you add all the numbers up, it comes out in that total,” he said.  “The purchased water becomes the wildcard all the time.”

Scientists Thought Parkinson’s Was in Our Genes. It Might Be in the Water

Parkinson’s disease has environmental toxic factors, not just genetic.

Skip to main contentScientists Thought Parkinson’s Was in Our Genes. It Might Be in the WaterNew ideas about chronic illness could revolutionize treatment, if we take the research seriously.Photograph: Rachel JessenThe Big Story is exclusive to subscribers.Start your free trial to access The Big Story and all premium newsletters.—cancel anytime.START FREE TRIALAlready a subscriber? Sign InThe Big Story is exclusive to subscribers. START FREE TRIALword word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word word wordmmMwWLliI0fiflO&1mmMwWLliI0fiflO&1mmMwWLliI0fiflO&1mmMwWLliI0fiflO&1mmMwWLliI0fiflO&1mmMwWLliI0fiflO&1mmMwWLliI0fiflO&1

Drinking water contaminated with Pfas probably increases risk of infant mortality, study finds

Study of 11,000 births in New Hampshire shows residents’ reproductive outcomes near contaminated sitesDrinking water contaminated with Pfas chemicals probably increases the risk of infant mortality and other harm to newborns, a new peer-reviewed study of 11,000 births in New Hampshire finds.The first-of-its-kind University of Arizona research found drinking well water down gradient from a Pfas-contaminated site was tied to an increase in infant mortality of 191%, pre-term birth of 20%, and low-weight birth of 43%. Continue reading...

Drinking water contaminated with Pfas chemicals probably increases the risk of infant mortality and other harm to newborns, a new peer-reviewed study of 11,000 births in New Hampshire finds.The first-of-its-kind University of Arizona research found drinking well water down gradient from a Pfas-contaminated site was tied to an increase in infant mortality of 191%, pre-term birth of 20%, and low-weight birth of 43%.It was also tied to an increase in extremely premature birth and extremely low-weight birth by 168% and 180%, respectively.The findings caught authors by surprise, said Derek Lemoine, a study co-author and economics professor at the University of Arizona who focuses on environmental policymaking and pricing climate risks.“I don’t know if we expected to find effects this big and this detectable, especially given that there isn’t that much infant mortality, and there aren’t that many extremely low weight or pre-term births,” Lemoine said. “But it was there in the data.”The study also weighed the cost of societal harms in drinking contaminated water against up-front cleanup costs, and found it to be much cheaper to address Pfas water pollution.Extrapolating the findings to the entire US population, the authors estimate a nearly $8bn negative annual economic impact just in increased healthcare costs and lost productivity. The cost of complying with current regulations for removing Pfas in drinking water is estimated at about $3.8bn.“We are trying to put numbers on this and that’s important because when you want to clean up and regulate Pfas, there’s a real cost to it,” Lemoine said.Pfas are a class of at least 16,000 compounds often used to help products resist water, stains and heat. They are called “forever chemicals” because they do not naturally break down and accumulate in the environment, and they are linked to serious health problems such as cancer, kidney disease, liver problems, immune disorders and birth defects.Pfas are widely used across the economy, and industrial sites that utilize them in high volume often pollute groundwater. Military bases and airports are among major sources of Pfas pollution because the chemicals are used in firefighting foam. The federal government estimated that about 95 million people across the country drink contaminated water from public or private wells.Previous research has raised concern about the impact of Pfas exposure on fetuses and newborns.Among those are toxicological studies in which researchers examine the chemicals’ impact on lab animals, but that leaves some question about whether humans experience the same harms, Lemoine said.Other studies are correlative and look at the levels of Pfas in umbilical cord blood or in newborns in relation to levels of disease. Lemoine said those findings are not always conclusive, in part because many variables can contribute to reproductive harm.The new natural study is unique because it gets close to “isolating the effect of the Pfas itself, and not anything around it”, Lemoine said.Researchers achieved this by identifying 41 New Hampshire sites contaminated with Pfoa and Pfos, two common Pfas compounds, then using topography data to determine groundwater flow direction. The authors then examined reproductive outcomes among residents down gradient from the sites.Researchers chose New Hampshire because it is the only state where Pfas and reproductive data is available, Lemoine said. Well locations are confidential, so mothers were unaware of whether their water source was down gradient from a Pfas-contaminated site. That created a randomization that allows for causal inference, the authors noted.The study’s methodology is rigorous and unique, and underscores “that Pfas is no joke, and is toxic at very low concentrations”, said Sydney Evans, a senior science analyst with the Environmental Working Group non-profit. The group studies Pfas exposures and advocates for tighter regulations.The study is in part effective because mothers did not know whether they were exposed, which created the randomization, Evans said, but she noted that the state has the information. The findings raise questions about whether the state should be doing a similar analysis and alerting mothers who are at risk, Evans said.Lemoine said the study had some limitations, including that authors don’t know the mothers’ exact exposure levels to Pfas, nor does the research account for other contaminants that may be in the water. But he added that the findings still give a strong picture of the chemicals’ effects.Granular activated carbon or reverse osmosis systems can be used by water treatment plants and consumers at home to remove many kinds of Pfas, and those systems also remove other contaminants.The Biden administration last year put in place limits in drinking water for six types of Pfas, and gave water utilities several years to install systems.The Trump administration is moving to undo the limits for some compounds. That would probably cost the public more in the long run. Utility customers pay the cost of removing Pfas, but the public “also pays the cost of drinking contaminated water, which is bigger”, Lemoine said.

Meet the weird, wonderful creatures that live in Australia’s desert water holes. They might not be there much longer

From water fleas to seed shrimp, Australia’s desert rock holes shelter unique animals found nowhere else. But as the climate warms, their homes are at risk.

The Conversation , CC BY-NDYou might think of Australia’s arid centre as a dry desert landscape devoid of aquatic life. But it’s actually dotted with thousands of rock holes – natural rainwater reservoirs that act as little oases for tiny freshwater animals and plants when they hold water. They aren’t teeming with fish, but are home to all sorts of weird and wonderful invertebrates, important to both First Nations peoples and desert animals. Predatory damselflies patrol the water in search of prey, while alien-like water fleas and seed shrimp float about feeding on algae. Often overlooked in favour of more photogenic creatures, invertebrates make up more than 97% of all animal species, and are immensely important to the environment. Our new research reveals 60 unique species live in Australia’s arid rock holes. We will need more knowledge to protect them in a warming climate. Arid land rock holes play host to a surprisingly diverse range of invertebrates. Author provided, CC BY-ND Overlooked, but extraordinary Invertebrates are animals without backbones. They include many different and beautiful organisms, such as butterflies, beetles, worms and spiders (though perhaps beauty is in the eye of the beholder!). These creatures provide many benefits to Australian ecosystems (and people): pollinating plants, recycling nutrients in the soil, and acting as a food source for other animals. Yet despite their significance, invertebrates are usually forgotten in public discussions about climate change. Freshwater invertebrates in arid Australia are rarely the focus of research, let alone media coverage. This is due to a combination of taxonomic bias, where better-known “charismatic” species are over-represented in scientific studies, and the commonly held misconception that dry deserts are less affected by climate change. Invertebrates in desert oases include insects and crustaceans, often smaller than 5 cm in length. Invertebrates in this picture include three seed shrimp, one pea shrimp, a water flea, a water boatman and a non-biting midge larvae. Author provided, CC BY-ND Oases of life Arid rock-holes are small depressions that have been eroded into rock over time. They completely dry out during certain times of year, making them difficult environments to live in. But when rain fills them up, many animals rely on them for water. When it is hot, water presence is brief, sometimes for only a few days. But during cooler months, they can remain wet for a few months. Eggs that have been lying dormant in the sediments hatch. Other invertebrates (particularly those with wings) seek them out, sometimes across very long distances. In the past, this variability has made ecological research extremely difficult. Our new research explored the biodiversity in seven freshwater rock holes in South Australia’s Gawler Ranges. For the first time, we used environmental DNA techniques on water samples from these pools. Similar to forensic DNA, environmental DNA refers to the traces of DNA left behind by animals in the environment. By sweeping an area for eDNA, we minimise disturbance to species, avoid having to collect the animals themselves, and get a clear snapshot of what is – or was – in an ecosystem. We assume that the capture window for eDNA goes back roughly two weeks. These samples showed that not only were these isolated rock holes full of invertebrate life, but each individual rock hole had a unique combination of animals in it. These include tiny animals such as seed shrimp, water fleas, water boatman and midge larvae. Due to how dry the surrounding landscape is, these oases are often the only habitats where creatures like these can be seen. Culturally significant These arid rock holes are of great cultural significance to several Australian First Nations groups, including the Barngarla, Kokatha and Wirangu peoples. These are the three people and language groups in the Gawler Ranges Aboriginal Corporation, who hold native title in the region and actively manage the rock holes using traditional practices. As reliable sources of freshwater in otherwise very dry landscapes, these locations provided valuable drinking water and resting places to many cultural groups. Some of the managed rock holes hold up to 500 litres of water, but elsewhere they are even deeper. Diverse practices were traditionally developed to actively manage rock holes and reliably locate them. Some of these practices — such as regular cleaning and limiting access by animals — are still maintained today. Freshwater granite rock-holes are still managed using traditional practices in the Gawler Ranges region. Author provided, CC BY-ND Threatened by climate change Last year, Earth reached 1.5°C of warming above pre-industrial levels for the first time. Australia has seen the dramatic consequences of global climate change firsthand: increasingly deadly, costly and devastating bushfires, heatwaves, droughts and floods. Climate change means less frequent and more unpredictable rainfall for Australia. There has been considerable discussion of what this means for Australia’s rivers, lakes and people. But smaller water sources, including rock holes in Australia’s deserts, don’t get much attention. Australia is already seeing a shift: winter rainfall is becoming less reliable, and summer storms are more unpredictable. Water dries out quickly in the summer heat, so wildlife adapted to using rock holes will increasingly have to go without. Storm clouds roll in over the South Australian desert. Author provided, CC BY-ND Drying out? Climate change threatens the precious diversity supported by rock holes. Less rainfall and higher temperatures in southern and central Australia mean we expect they will fill less, dry more quickly, and might be empty during months when they were historically full. This compounds the ongoing environmental change throughout arid Australia. Compared with iconic invasive species such as feral horses in Kosciuszko National Park, invasive species in arid Australia are overlooked. These include feral goats, camels and agricultural animal species that affect water quality. Foreign plants can invade freshwater systems. Deeper understanding Many gaps in our knowledge remain, despite the clear need to protect these unique invertebrates as their homes get drier. Without a deeper understanding of rock-hole biodiversity, governments and land managers are left without the right information to prevent further species loss. Studies like this one are an important first step because they establish a baseline on freshwater biodiversity in desert rock holes. With a greater understanding of the unique animals that live in these remote habitats, we will be better equipped to conserve them. The freshwater damselfly visit granite rock-holes after rain and lay their eggs directly into the water. Author provided, CC BY-ND Brock A. Hedges received funding from Nature Foundation, The Ecological Society of Australia and the Department of Agriculture, Water and Environment. Brock A. Hedges currently receives funding from the Japan Society for the Promotion of Science.James B. Dorey receives funding from the University of Wollongong. Perry G. Beasley-Hall receives funding from the Australian Biological Resources Study.

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