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U.S. Drinking-Water Systems Still Haven't Defeated This Nasty Parasite

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Thursday, December 7, 2023

Thirty years ago a tiny parasite in the water supply in Milwaukee, Wis., touched off the largest waterborne disease outbreak in U.S. history. Although that city’s water is now renowned for its high quality, public health departments across the country are still battling the same diarrhea-inducing organism. What makes it so tough?Reports of gastrointestinal illnesses throughout the Milwaukee area began pouring into the city’s health department in April 1993. A local infectious disease physician eventually identified a case of cryptosporidiosis, an infection with the parasitic protist Cryptosporidium. When health officials began testing stool samples for this organism, they found many more cases. The parasite, they realized, was lurking in the pipes: for the past two weeks the Milwaukee Water Works had been receiving dozens of telephone complaints about local tap water appearing cloudy.At a hastily called late-night meeting on April 7 of that year, Milwaukee’s mayor John Norquist asked the late Jeff B. Davis, an epidemiologist at the Wisconsin Division of Public Health, “Would you drink the water?” Davis’s answer, “No, I wouldn’t,” shocked the mayor. Within an hour, Norquist arranged a press conference and declared Milwaukee’s drinking water unsafe for consumption unless it was boiled. Television news anchors scrambled to report the mayor’s “boil order” for water, and newspaper editors reworked their front pages.Over the next eight days Milwaukee cleaned and disinfected its water treatment plants, state and federal officials declared the supply safe for consumption, and the boil order was rescinded. But by that time more than 400,000 local residents—approximately half of the 800,000 people served by Milwaukee’s water-distribution system—had reported cryptosporidiosis symptoms, including diarrhea, vomiting, fever, chills and body aches. Pharmacy shelves ran out of over-the-counter gastrointestinal medicines. More than 4,000 people were admitted to local hospitals. By the time the crisis subsided, at least 100 people had died from exposure to the parasite.Cryptosporidium remains a serious health problem today. The Centers for Disease Control and Prevention reported 444 outbreaks of cryptosporidiosis in the U.S. between 2009 and 2017, and the number has increased by an average of 13 percent each year. A 2019 CDC report estimates that 823,000 people get the illness each year and that fewer than two percent of cases are reported to the CDC.These outbreaks occur across the country and beyond. In late September 2023 the Baltimore Department of Public Works announced that Cryptosporidium had been detected in samples from a large drinking-water reservoir. The city issued a boil-water order for people with health conditions that could make them more vulnerable. Recent outbreaks have also been reported in North Carolina and Oregon. The U.K. and New Zealand have also battled severe outbreaks in the last few months.What makes cryptosporidiosis such a nasty and stubborn health problem? First reported in humans in 1976, this extremely contagious disease spreads when people drink water contaminated with Cryptosporidium. In the water supply the parasite remains in a life stage called an oocyst, which is four to five micrometers in diameter and shielded by a protective outer shell. This helps the organism resist pathogen-killing processes traditionally used by water treatment facilities.Once the oocysts are ingested, the shells crack—releasing Cryptosporidium into the host’s intestines, where as few as 10 of the parasites can cause an infection. These parasites reproduce at an incredible speed: Just three to four days after infection, a person can shed as many as one billion oocysts in diarrhea in a single day. And this shedding continues for an average of 18 days.“Cryptosporidium has a long incubation period,” says CDC epidemiologist Michele Hlavsa. “From the point when you’re exposed to the pathogen to the point where you develop symptoms, the time frame could be a week or more. Then these people have to be sick enough to see a doctor and get tested.”Cryptosporidiosis can cause one to two weeks of nausea, stomach cramps, vomiting, dehydration and fever, but the most commonly reported symptom is watery diarrhea. Although such claims might sound hyperbolic, Hlavsa says infected people have reported up to 40 episodes of watery stools per day.But diarrhea is a symptom of many illnesses, and most laboratories do not routinely test stool samples for Cryptosporidium. Because Cryptosporidium is hard to detect and infected people can be contagious for several weeks, epidemiologists assume that many cases may be unreported and that outbreaks may be more widespread than they appear to be. Some experts estimate that only one percent of confirmed Cryptosporidium infections are officially documented.Scientists do know how to prevent Cryptosporidium outbreaks: kill or filter out the parasites in public drinking water before it gets to the tap. The Environmental Protection Agency’s Interim Enhanced Surface Water Treatment Rule (IESWTR) requires large water systems to remove 99 percent of Cryptosporidium from drinking water. In 1998 the EPA estimated that implementing this rule would “reduce the likelihood of the occurrence of outbreaks of cryptosporidiosis.”Yet removing these parasites from public drinking water is an extremely challenging process. The hard-shelled oocytes are resistant to the chlorine disinfectants used by many municipal water treatment plants. Fortunately, there are other options.Advanced technologies such as ozonation have proved effective in removing oocysts. In this process a device called an ozone generator runs a stream of oxygen through a high-voltage electric field, which breaks down some of the oxygen molecules, whose atoms combine with other oxygen molecules to produce ozone. The resulting oxygen-ozone mixture is pumped into holding tanks, where the highly corrosive ozone destroys the cell walls of any microorganisms in the water—rendering parasites such as Cryptosporidium inert—before breaking down naturally. The water then moves through several more filtration and treatment processes before reaching household taps.Another option is exposing water to ultraviolet (UV) light, which inactivates Cryptosporidium oocysts and renders the parasite noninfectious. “UV is an interesting concept—basically irradiating the water as it passes through a UV reactor—but the process doesn’t necessarily destroy the organism. The process just renders it so that the parasite can’t reproduce,” says Dan Welk, water plants manager at the Milwaukee Water Works.After Milwaukee’s Cryptosporidium outbreak, the city invested more than $500 million in upgrading its water treatment plant facilities; it has since garnered industry awards for the quality of its drinking water. Milwaukee’s treatment process starts with ozonation and moves through a series of steps designed to remove Cryptosporidium. And the city is open to doing more. “We’re always looking to see if there are other treatment techniques that we could potentially add to the plant to address an emerging concern,” Welk says.Not every U.S. city tests its drinking water for Cryptosporidium, however, and it continues to strike every year. According to the EPA’s Drinking Water Infrastructure Needs Survey and Assessment (DWINSA) released in September 2023, the U.S. needs to invest $625 billion over the next 20 years to upgrade its drinking-water infrastructure.In the meantime public health experts are working to improve diagnostic testing and reporting tools, which help them track outbreaks. But the CDC says accurate Cryptosporidium reporting is still several years away—meaning there is still the threat of another widespread outbreak such as the one that occurred in Milwaukee. “Cryptosporidium isn’t just spreading locally. It’s spreading over multiple jurisdictions—and we might not be picking up these outbreaks,” Hlavsa says. “An infection could start in one spot and move quickly to five different states.”

The U.S.’s largest-ever outbreak of waterborne illness—cryptosporidiosis—hit Milwaukee 30 years ago. Why are many other water systems still vulnerable to the same parasite today?

Thirty years ago a tiny parasite in the water supply in Milwaukee, Wis., touched off the largest waterborne disease outbreak in U.S. history. Although that city’s water is now renowned for its high quality, public health departments across the country are still battling the same diarrhea-inducing organism. What makes it so tough?

Reports of gastrointestinal illnesses throughout the Milwaukee area began pouring into the city’s health department in April 1993. A local infectious disease physician eventually identified a case of cryptosporidiosis, an infection with the parasitic protist Cryptosporidium. When health officials began testing stool samples for this organism, they found many more cases. The parasite, they realized, was lurking in the pipes: for the past two weeks the Milwaukee Water Works had been receiving dozens of telephone complaints about local tap water appearing cloudy.

At a hastily called late-night meeting on April 7 of that year, Milwaukee’s mayor John Norquist asked the late Jeff B. Davis, an epidemiologist at the Wisconsin Division of Public Health, “Would you drink the water?” Davis’s answer, “No, I wouldn’t,” shocked the mayor. Within an hour, Norquist arranged a press conference and declared Milwaukee’s drinking water unsafe for consumption unless it was boiled. Television news anchors scrambled to report the mayor’s “boil order” for water, and newspaper editors reworked their front pages.

Over the next eight days Milwaukee cleaned and disinfected its water treatment plants, state and federal officials declared the supply safe for consumption, and the boil order was rescinded. But by that time more than 400,000 local residents—approximately half of the 800,000 people served by Milwaukee’s water-distribution system—had reported cryptosporidiosis symptoms, including diarrhea, vomiting, fever, chills and body aches. Pharmacy shelves ran out of over-the-counter gastrointestinal medicines. More than 4,000 people were admitted to local hospitals. By the time the crisis subsided, at least 100 people had died from exposure to the parasite.

Cryptosporidium remains a serious health problem today. The Centers for Disease Control and Prevention reported 444 outbreaks of cryptosporidiosis in the U.S. between 2009 and 2017, and the number has increased by an average of 13 percent each year. A 2019 CDC report estimates that 823,000 people get the illness each year and that fewer than two percent of cases are reported to the CDC.

These outbreaks occur across the country and beyond. In late September 2023 the Baltimore Department of Public Works announced that Cryptosporidium had been detected in samples from a large drinking-water reservoir. The city issued a boil-water order for people with health conditions that could make them more vulnerable. Recent outbreaks have also been reported in North Carolina and Oregon. The U.K. and New Zealand have also battled severe outbreaks in the last few months.

What makes cryptosporidiosis such a nasty and stubborn health problem? First reported in humans in 1976, this extremely contagious disease spreads when people drink water contaminated with Cryptosporidium. In the water supply the parasite remains in a life stage called an oocyst, which is four to five micrometers in diameter and shielded by a protective outer shell. This helps the organism resist pathogen-killing processes traditionally used by water treatment facilities.

Once the oocysts are ingested, the shells crack—releasing Cryptosporidium into the host’s intestines, where as few as 10 of the parasites can cause an infection. These parasites reproduce at an incredible speed: Just three to four days after infection, a person can shed as many as one billion oocysts in diarrhea in a single day. And this shedding continues for an average of 18 days.

Cryptosporidium has a long incubation period,” says CDC epidemiologist Michele Hlavsa. “From the point when you’re exposed to the pathogen to the point where you develop symptoms, the time frame could be a week or more. Then these people have to be sick enough to see a doctor and get tested.”

Cryptosporidiosis can cause one to two weeks of nausea, stomach cramps, vomiting, dehydration and fever, but the most commonly reported symptom is watery diarrhea. Although such claims might sound hyperbolic, Hlavsa says infected people have reported up to 40 episodes of watery stools per day.

But diarrhea is a symptom of many illnesses, and most laboratories do not routinely test stool samples for Cryptosporidium. Because Cryptosporidium is hard to detect and infected people can be contagious for several weeks, epidemiologists assume that many cases may be unreported and that outbreaks may be more widespread than they appear to be. Some experts estimate that only one percent of confirmed Cryptosporidium infections are officially documented.

Scientists do know how to prevent Cryptosporidium outbreaks: kill or filter out the parasites in public drinking water before it gets to the tap. The Environmental Protection Agency’s Interim Enhanced Surface Water Treatment Rule (IESWTR) requires large water systems to remove 99 percent of Cryptosporidium from drinking water. In 1998 the EPA estimated that implementing this rule would “reduce the likelihood of the occurrence of outbreaks of cryptosporidiosis.”

Yet removing these parasites from public drinking water is an extremely challenging process. The hard-shelled oocytes are resistant to the chlorine disinfectants used by many municipal water treatment plants. Fortunately, there are other options.

Advanced technologies such as ozonation have proved effective in removing oocysts. In this process a device called an ozone generator runs a stream of oxygen through a high-voltage electric field, which breaks down some of the oxygen molecules, whose atoms combine with other oxygen molecules to produce ozone. The resulting oxygen-ozone mixture is pumped into holding tanks, where the highly corrosive ozone destroys the cell walls of any microorganisms in the water—rendering parasites such as Cryptosporidium inert—before breaking down naturally. The water then moves through several more filtration and treatment processes before reaching household taps.

Another option is exposing water to ultraviolet (UV) light, which inactivates Cryptosporidium oocysts and renders the parasite noninfectious. “UV is an interesting concept—basically irradiating the water as it passes through a UV reactor—but the process doesn’t necessarily destroy the organism. The process just renders it so that the parasite can’t reproduce,” says Dan Welk, water plants manager at the Milwaukee Water Works.

After Milwaukee’s Cryptosporidium outbreak, the city invested more than $500 million in upgrading its water treatment plant facilities; it has since garnered industry awards for the quality of its drinking water. Milwaukee’s treatment process starts with ozonation and moves through a series of steps designed to remove Cryptosporidium. And the city is open to doing more. “We’re always looking to see if there are other treatment techniques that we could potentially add to the plant to address an emerging concern,” Welk says.

Not every U.S. city tests its drinking water for Cryptosporidium, however, and it continues to strike every year. According to the EPA’s Drinking Water Infrastructure Needs Survey and Assessment (DWINSA) released in September 2023, the U.S. needs to invest $625 billion over the next 20 years to upgrade its drinking-water infrastructure.

In the meantime public health experts are working to improve diagnostic testing and reporting tools, which help them track outbreaks. But the CDC says accurate Cryptosporidium reporting is still several years away—meaning there is still the threat of another widespread outbreak such as the one that occurred in Milwaukee. “Cryptosporidium isn’t just spreading locally. It’s spreading over multiple jurisdictions—and we might not be picking up these outbreaks,” Hlavsa says. “An infection could start in one spot and move quickly to five different states.”

Read the full story here.
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Rural Texas towns report cyberattacks that caused one water system to overflow

Local officials said the public was not put in any danger and the attempts were reported to federal authorities.

Subscribe to The Y’all — a weekly dispatch about the people, places and policies defining Texas, produced by Texas Tribune journalists living in communities across the state. A hack that caused a small Texas town's water system to overflow in January has been linked to a shadowy Russian hacktivist group, the latest case of a U.S. public utility becoming a target of foreign cyberattacks. The attack was one of three on small towns in the rural Texas. Local officials said the public was not put in any danger and the attempts were reported to federal authorities. "There were 37,000 attempts in four days to log into our firewall," said Mike Cypert, city manager of Hale Center, which is home to about 2,000 residents. The attempted hack failed as the city "unplugged" the system and operated it manually, he added. In Muleshoe, about 60 miles to the west and with a population of about 5,000, hackers caused the water system to overflow before it was shut down and taken over manually by officials, city manager Ramon Sanchez told CNN. He did not immediately respond to phone calls from The Associated Press seeking comment. "The incident was quickly addressed and resolved," Sanchez said in a statement, according to KAMC-TV. "The city's water disinfectant system was not affected, and the public water system nor the public was in any danger." At least one of the attacks was linked this week by Mandiant, a U.S. cybersecurity firm, to a shadowy Russian hacktivist group that it said could be working with or part of a Russian military hacking unit. Related Story April 11, 2024 The group, calling itself CyberArmyofRussia_Reborn, claimed responsibility for January attacks on water facilities in the United States and Poland that got little attention at the time. Cybersecurity researchers say CyberArmyofRussia_Reborn was among groups suspected of Russian government ties that engaged last year in low-complexity attacks against Ukraine and its allies, including denial-of-service data barrages that temporarily knock websites offline. Sometimes such groups claim responsibility for attacks that were actually carried out by Kremlin military intelligence hackers, Microsoft reported in December. Cypert, the Hale Center city manager, said he has turned information over to FBI and the Department of Homeland Security. The FBI declined to comment, and the Cybersecurity and Infrastructure Security Agency, a branch of DHS, referred questions to the cities that were targeted. In Lockney, about 25 miles east of Hale Center and home to around 1,500 people, cyberattackers were thwarted before they could access that town's water system, city manager Buster Poling said. "It didn't cause any problems except being a nuisance," Poling said. Last year CISA put out an advisory following November hacks on U.S. water facilities attributed to Iranian state groups who said they were targeting facilities using Israeli equipment. Deputy national security adviser Anne Neuberger said in December that attacks by Iranian hackers — as well as a separate spate of ransomware attacks on the health care industry — should be seen as a call to action by utilities and industry to tighten cybersecurity. In March, Environmental Protection Agency Administrator Michael S. Regan and Jake Sullivan, assistant to the president for National Security Affairs, sent a letter to the nation's governors asking them to take steps to protect the water supply, including assessing cybersecurity and planning for a cyberattack. "Drinking water and wastewater systems are an attractive target for cyberattacks because they are a lifeline critical infrastructure sector but often lack the resources and technical capacity to adopt rigorous cybersecurity practices," Regan and Sullivan wrote. Tickets are on sale now for the 2024 Texas Tribune Festival, happening in downtown Austin Sept. 5-7. Get your TribFest tickets before May 1 and save big!

E.P.A. Will Make Polluters Pay to Clean Up Two PFAS Compounds

The step follows an extraordinary move that requires utilities to reduce the levels of carcinogenic PFAS compounds in drinking water to near-zero.

The Biden administration is designating two “forever chemicals,” man-made compounds that are linked to serious health risks, as hazardous substances under the Superfund law, shifting responsibility for their cleanup to polluters from taxpayers.The new rule announced on Friday empowers the government to force the many companies that manufacture or use perfluorooctanoic acid, also known as PFOA, and perfluorooctanesulfonic acid, known as PFOS, to monitor any releases into the environment and be responsible for cleaning them up.The compounds, found in everything from dental floss to firefighting foams to children’s toys, are called forever chemicals because they degrade very slowly and can accumulate in the body and the environment. Exposure to PFAS has been associated with metabolic disorders, decreased fertility in women, developmental delays in children and increased risk of some prostate, kidney and testicular cancers, according to the Environmental Protection Agency.The chemicals are so ubiquitous that they can be found in the blood of almost every person in the United States. In 2022, the E.P.A. found the chemicals could cause harm at levels “much lower than previously understood” and that almost no level of exposure was safe.The pair of compounds are part of a larger family of chemical substances known collectively as PFAS.The announcement follows an extraordinary move last week from the E.P.A. mandating that water utilities reduce the PFAS in drinking water to near-zero levels. The agency has also proposed to designate seven additional PFAS chemicals as hazardous substances.Subscribe to The Times to read as many articles as you like.

Unlocking Arctic Secrets Through Mercury and Ice

MIT PhD candidate Emma Bullock studies the local and global impacts of changing mineral levels in Arctic groundwater. A quick scan of Emma Bullock’s CV...

During a near-shore Beaufort Sea sampling campaign in July 2023, PhD student Emma Bullock sampled ocean water with recent meltwater inputs to test for radium isotopes, trace metals, carbon, nutrients, and mercury. Credit: Paul HendersonMIT PhD candidate Emma Bullock studies the local and global impacts of changing mineral levels in Arctic groundwater.A quick scan of Emma Bullock’s CV reads like those of many other MIT graduate students: She has served as a teaching assistant, written several papers, garnered grants from prestigious organizations, and acquired extensive lab and programming skills. But one skill sets her apart: “fieldwork experience and survival training for Arctic research.”That’s because Bullock, a doctoral student in chemical oceanography at the Woods Hole Oceanographic Institution (WHOI), spends significant time collecting samples in the Arctic Circle for her research. Working in such an extreme environment requires comprehensive training in everything from Arctic gear usage and driving on unpaved roads to handling wildlife encounters — like the curious polar bear that got into her team’s research equipment. To date, she has ventured to Prudhoe Bay, Alaska, five times, where she typically spends long days — from 5:00 a.m. to 11 p.m. — collecting and processing samples from Simpson Lagoon. Her work focuses on Arctic environmental changes, particularly the effects of permafrost thaw on mercury levels in groundwater.“Even though I am doing foundational science, I can link it directly to communities in that region that are going to be impacted by the changes that we are seeing,” she says. “As the mercury escapes from the permafrost, it has the potential to impact not just Arctic communities but also anyone who eats fish in the entire world.”Weathering a Storm of SetbacksGrowing up in rural Vermont, Bullock spent a lot of time outside, and she attributes her strong interest in environmental studies to her love of nature as a child. Despite her conviction about a career path involving the environment, her path to the Institute has not been easy. In fact, Bullock weathered several challenges and setbacks on the road to MIT.As an undergraduate at Haverford College, Bullock quickly recognized that she did not have the same advantages as other students. She realized that her biggest challenge in pursuing an academic career was her socioeconomic background. She says, “In Vermont, the cost of living is a bit lower than a lot of other areas. So, I didn’t quite realize until I got to undergrad that I was not as middle-class as I thought.” Bullock had learned financial prudence from her parents, which informed many of the decisions she made as a student. She says, “I didn’t have a phone in undergrad because it was a choice between getting a good laptop that I could do research on or a phone. And so I went with the laptop.”Bullock majored in chemistry because Haverford did not offer an environmental science major. To gain experience in environmental research, she joined the lab of Helen White, focusing on the use of silicone bands as passive samplers of volatile organic compounds in honeybee hives. A pivotal moment occurred when Bullock identified errors in a collaborative project. She says, “[Dr. White and I] brought the information about flawed statistical tests to the collaborators, who were all men. They were not happy with that. They made comments that they did not like being told how to do chemistry by women.”White sat Bullock down and explained the pervasiveness of sexism in this field. “She said, ‘You have to remember that it is not you. You are a good scientist. You are capable,’” Bullock recalls. That experience strengthened her resolve to become an environmental scientist. “The way that Dr. Helen White approached dealing with this problem made me want to stick in the STEM field, and in the environmental and geochemistry fields specifically. It made me realize that we need more women in these fields,” she says.As she reached the end of college, Bullock knew that she wanted to continue her educational journey in environmental science. “Environmental science impacts the world around us in such visible ways, especially now with climate change,” she says. She submitted applications to many graduate programs, including to MIT, which was White’s alma mater, but was rejected by all of them.Undeterred, Bullock decided to get more research experience. She took a position as a lab technician at the Max Planck Institute of Marine Microbiology in Bremen, Germany, where she studied methane emissions from seagrass beds — her first foray into chemical oceanography. A year later, she applied to graduate schools again and was accepted by nearly all of the programs, including MIT. She hopes her experience can serve as a lesson for future applicants. “Just because you get rejected the first time does not mean that you’re not a good candidate. It just means that you may not have the right experience or that you didn’t understand the application process correctly,” she says.Understanding the Ocean Through the Lens of ChemistryUltimately, Bullock chose MIT because she was most interested in the specific scientific projects within the program and liked the sense of community. “It is a very unique program because we have the opportunity to take classes at MIT and access to the resources that MIT has, but we also perform research at Woods Hole,” she says. Some people warned her about the cutthroat nature of the Institute, but Bullock has found the exact opposite to be a true. “A lot of people think of MIT, and they think it is one of those top tier schools, so it must be competitive. My experience in this program is that it is very collaborative because our research is so individual and unique that you really can’t be competitive. What you are doing is so different from any other student,” she says.Bullock joined the group of Matthew Charette, senior scientist and director of the WHOI Sea Grant Program, which investigates the ocean through a chemical lens by characterizing the Arctic groundwater sampled during field campaigns in Prudhoe Bay, Alaska. Bullock analyzes mercury and biotoxic methylmercury levels impacted by permafrost thaw, which is already affecting the health of Arctic communities. For comparison, Bullock points to mercury-based dental fillings, which have been the subject of scientific scrutiny for health impacts. She says, “You get more mercury by eating sushi and tuna and salmon than you would by having a mercury-based dental filling.”Environmental Advocacy and Future AspirationsBullock has been recognized as an Arctic PASSION Ambassador for her work in the historically underresearched Arctic region. As part of this program, she was invited to participate in a “sharing circle,” which connected early-career scientists with Indigenous community members, and then empowered them to pass what they learned about the importance of Arctic research onto their communities. This experience has been the highlight of her PhD journey so far. She says, “It was small enough, and the people there were invested enough in the issues that we got to have very interesting, dynamic conversations, which doesn’t always happen at typical conferences.”Bullock has also spearheaded her own form of environmental activism via a project called en-justice, which she launched in September 2023. Through a website and a traveling art exhibit, the project showcases portraits and interviews of lesser-known environmental advocates that “have arguably done more for the environment but are not as famous” as household names like Greta Thunberg and Leonardo DiCaprio.“They are doing things like going to town halls, arguing with politicians, getting petitions signed … the very nitty-gritty type work. I wanted to create a platform that highlighted some of these people from around the country but also inspired people in their own communities to try and make a change,” she says. Bullock has also written an op-ed for the WHOI magazine, Oceanus, and has served as a staff writer for the MIT-WHOI Joint Program newsletter, “Through the Porthole.”After she graduates this year, Bullock plans to continue her focus on the Arctic. She says, “I find Arctic research very interesting, and there are so many unanswered research questions.” She also aspires to foster further interactions like the sharing circle.“Trying to find a way where I can help facilitate Arctic communities and researchers in terms of finding each other and finding common interests would be a dream role. But I don’t know if that job exists,” Bullock says. Given her track record of overcoming obstacles, odds are, she will turn these aspirations into reality.

Researching extreme environments

PhD candidate Emma Bullock studies the local and global impacts of changing mineral levels in Arctic groundwater.

A quick scan of Emma Bullock’s CV reads like those of many other MIT graduate students: She has served as a teaching assistant, written several papers, garnered grants from prestigious organizations, and acquired extensive lab and programming skills. But one skill sets her apart: “fieldwork experience and survival training for Arctic research.” That’s because Bullock, a doctoral student in chemical oceanography at the Woods Hole Oceanographic Institution (WHOI), spends significant time collecting samples in the Arctic Circle for her research. Working in such an extreme environment requires comprehensive training in everything from Arctic gear usage and driving on unpaved roads to handling wildlife encounters — like the curious polar bear that got into her team’s research equipment. To date, she has ventured to Prudhoe Bay, Alaska, five times, where she typically spends long days — from 5:00 a.m. to 11 p.m. — collecting and processing samples from Simpson Lagoon. Her work focuses on Arctic environmental changes, particularly the effects of permafrost thaw on mercury levels in groundwater. “Even though I am doing foundational science, I can link it directly to communities in that region that are going to be impacted by the changes that we are seeing,” she says. “As the mercury escapes from the permafrost, it has the potential to impact not just Arctic communities but also anyone who eats fish in the entire world.” Weathering a storm of setbacks Growing up in rural Vermont, Bullock spent a lot of time outside, and she attributes her strong interest in environmental studies to her love of nature as a child. Despite her conviction about a career path involving the environment, her path to the Institute has not been easy. In fact, Bullock weathered several challenges and setbacks on the road to MIT. As an undergraduate at Haverford College, Bullock quickly recognized that she did not have the same advantages as other students. She realized that her biggest challenge in pursuing an academic career was her socioeconomic background. She says, “In Vermont, the cost of living is a bit lower than a lot of other areas. So, I didn’t quite realize until I got to undergrad that I was not as middle-class as I thought.” Bullock had learned financial prudence from her parents, which informed many of the decisions she made as a student. She says, “I didn’t have a phone in undergrad because it was a choice between getting a good laptop that I could do research on or a phone. And so I went with the laptop.” Bullock majored in chemistry because Haverford did not offer an environmental science major. To gain experience in environmental research, she joined the lab of Helen White, focusing on the use of silicone bands as passive samplers of volatile organic compounds in honeybee hives. A pivotal moment occurred when Bullock identified errors in a collaborative project. She says, “[Dr. White and I] brought the information about flawed statistical tests to the collaborators, who were all men. They were not happy with that. They made comments that they did not like being told how to do chemistry by women.” White sat Bullock down and explained the pervasiveness of sexism in this field. “She said, ‘You have to remember that it is not you. You are a good scientist. You are capable,’” Bullock recalls. That experience strengthened her resolve to become an environmental scientist. “The way that Dr. Helen White approached dealing with this problem made me want to stick in the STEM field, and in the environmental and geochemistry fields specifically. It made me realize that we need more women in these fields,” she says. As she reached the end of college, Bullock knew that she wanted to continue her educational journey in environmental science. “Environmental science impacts the world around us in such visible ways, especially now with climate change,” she says. She submitted applications to many graduate programs, including to MIT, which was White’s alma mater, but was rejected by all of them. Undeterred, Bullock decided to get more research experience. She took a position as a lab technician at the Max Planck Institute of Marine Microbiology in Bremen, Germany, where she studied methane emissions from seagrass beds — her first foray into chemical oceanography. A year later, she applied to graduate schools again and was accepted by nearly all of the programs, including MIT. She hopes her experience can serve as a lesson for future applicants. “Just because you get rejected the first time does not mean that you’re not a good candidate. It just means that you may not have the right experience or that you didn’t understand the application process correctly,” she says. Understanding the ocean through the lens of chemistry Ultimately, Bullock chose MIT because she was most interested in the specific scientific projects within the program and liked the sense of community. “It is a very unique program because we have the opportunity to take classes at MIT and access to the resources that MIT has, but we also perform research at Woods Hole,” she says. Some people warned her about the cutthroat nature of the Institute, but Bullock has found the exact opposite to be a true. “A lot of people think of MIT, and they think it is one of those top tier schools, so it must be competitive. My experience in this program is that it is very collaborative because our research is so individual and unique that you really can’t be competitive. What you are doing is so different from any other student,” she says. Bullock joined the group of Matthew Charette, senior scientist and director of the WHOI Sea Grant Program, which investigates the ocean through a chemical lens by characterizing the Arctic groundwater sampled during field campaigns in Prudhoe Bay, Alaska. Bullock analyzes mercury and biotoxic methylmercury levels impacted by permafrost thaw, which is already affecting the health of Arctic communities. For comparison, Bullock points to mercury-based dental fillings, which have been the subject of scientific scrutiny for health impacts. She says, “You get more mercury by eating sushi and tuna and salmon than you would by having a mercury-based dental filling.” Promoting environmental advocacy Bullock has been recognized as an Arctic PASSION Ambassador for her work in the historically underresearched Arctic region. As part of this program, she was invited to participate in a “sharing circle,” which connected early-career scientists with Indigenous community members, and then empowered them to pass what they learned about the importance of Arctic research onto their communities. This experience has been the highlight of her PhD journey so far. She says, “It was small enough, and the people there were invested enough in the issues that we got to have very interesting, dynamic conversations, which doesn’t always happen at typical conferences.” Bullock has also spearheaded her own form of environmental activism via a project called en-justice, which she launched in September 2023. Through a website and a traveling art exhibit, the project showcases portraits and interviews of lesser-known environmental advocates that “have arguably done more for the environment but are not as famous” as household names like Greta Thunberg and Leonardo DiCaprio. “They are doing things like going to town halls, arguing with politicians, getting petitions signed … the very nitty-gritty type work. I wanted to create a platform that highlighted some of these people from around the country but also inspired people in their own communities to try and make a change,” she says. Bullock has also written an op-ed for the WHOI magazine, Oceanus, and has served as a staff writer for the MIT-WHOI Joint Program newsletter, “Through the Porthole.” After she graduates this year, Bullock plans to continue her focus on the Arctic. She says, “I find Arctic research very interesting, and there are so many unanswered research questions.” She also aspires to foster further interactions like the sharing circle. “Trying to find a way where I can help facilitate Arctic communities and researchers in terms of finding each other and finding common interests would be a dream role. But I don’t know if that job exists,” Bullock says. Given her track record of overcoming obstacles, odds are, she will turn these aspirations into reality.

‘It’s only been six weeks since they found lead in applesauce’

Lead still plagues American’s water and homes 40 years after the first federal bans

In the United States, despite a decades-long ban, millions of people still face the invisible threat of lead poisoning in their homes and water systems. Lead is a potent neurotoxin that impairs brain development in children and causes an array of health issues in adults, including high blood pressure and kidney damage, according to a U.S. National Institute of Health study and almost every other journal on the issue.The threat of lead is silent. Those affected often show no apparent symptoms, yet the damage can be lifelong and irreversible. Children exposed to lead can experience far-reaching societal consequences, according to various studies, including lower IQ and a host of behavioral problems. They earn less throughout their lives and work fewer years.More than 50% of all children in the United States under six years old have detectable lead in their blood, according to a 2021 study published in the Journal of the American Medical Association (JAMA).Removal of the source is the only way to reduce harm. Nevertheless, startling federal data reveals that 22 million Americans still get their drinking water through lead pipes, and around 38 million homes still contain lead-based paint.The issue predominantly plagues urban centers like Chicago, New York, Philadelphia, Cleveland, and Detroit, with some overlap for lead pipes and paint. Chicago tops the list on both fronts, with an alarming 400,000 lead pipelines—contaminating the water of 75% of city blocks. A recent study published in March 2024 in JAMA highlights a troubling statistic: nearly 70% of Chicago’s children under six live in these neighborhoods. Black and Hispanic communities are disproportionately affected, with less frequent testing yet higher exposure rates. While the paint is more challenging to track, it’s estimated that 99% of homes built in Chicago before 1978 have some level of paint toxicity. That constitutes a vast majority of the city’s housing stock.Despite the known risks, efforts to remove lead from our homes and water have been slow, hindered by decades of political inertia and lobbying in Congress. In late 2023, the Environmental Protection Agency proposed a new rule that seeks to rid the country of lead pipes in 10 years.Reckon spoke to Dr. Mary Jean Brown, adjunct professor of social and behavioral sciences at Harvard’s T.H. Chan School of Public Health, about why lead persists and what you can do about it.Reckon:The country seems awash with various toxic harms that advocacy groups and state and federal governments are trying to address. Many of these threats are seemingly new. Yet the ban on lead pipes was introduced 40 years ago. Why do we still see them in so many municipalities?Dr. Mary Jean Brown:Lead is a very useful metal that we’ve had since Pompeii, the Roman Empire, and in most places where water was being transported from one place to another. It was well into the 1980s that the city of Chicago still required all water pipes to be lead. In Alabama, one of the problems is that the only way you can really know if it’s a lead pipe is if you dig it up, take a key, and scratch it. It scratches easily because it’s soft. Most places don’t have a really good inventory of where their lead pipes are.I have some idea of what kinds of housing are most likely to have lead pipes. And certainly, the Gulf Coast of Alabama will have some of this housing. It’s not going to be like the high rises in New York City. Because you can’t run 100 housing units on two-inch water pipe. In the south, it’s pretty common as it will be in housing that was built before 1986, for the most part, because that’s when the federal ban went into effect for the use of lead water pipes.We’re building all kinds of beautiful things in cities, like parks, civic centers and theaters. Why are we not replacing the pipes when we build or pull up roads? This seems like a public health crisis. One reason is that we have a tendency in this business to put one source of lead in competition with another. Our focus until maybe 10 to 15 years ago, was lead paint and lead paint contaminated house dust and soil. We were worried about children who had blood levels that were considered very high, about 15 to 25 micrograms per deciliter. Now we worry about blood levels of 3.5 micrograms per deciliter. So, as we got better at lowering blood lead levels, we began to realize there are other sources that certainly are not as concentrated as what we were looking at in the 80s and the 90s, but they are still contributing to children’s blood lead levels.That’s combined with our inability to find a safe blood level for children. If a child has a blood level of five micrograms per deciliter, most places will go in and look at the house and try to figure out where the exposure is coming from to stop the exposure. That can keep the blood level from going up, but any damage that may have been done in the process of getting to five is probably irreversible. We need to prevent children from being exposed before they have a lead level that triggers an intervention. It’s a very tiny amount—3.5 micrograms per deciliter is 35 parts per billion. But you don’t have to have very much to get you up there, but that can do a very big amount of damage.We need to be proactive and remove lead from its sources, including pipes, paints, contaminated soil, and dust, especially around houses built before 1978. This includes industrial emissions, including putting lead in cinnamon for applesauce pouches.Applesauce! Is that thing?It’s only been six weeks since they found lead in applesauce. They found lead in cinnamon in the dollar stores as well. There’s always these new products that are coming to market. The customs people are pretty good about testing things, but things slip through. And there’s lead in spices and traditional teas and other things that people bring with them when they move to the States.Is there a ban on lead paint across the board?There’s a ban on lead in residential house paints, but there’s no ban on lead in the paint that goes on the line on roads or the paint that goes on your boat. It’s unfortunate that these other sources of lead paints tend to bleed into the residential market. You mentioned the effects that lead can have on children in small doses. What does exposure actually do to a child’s health and their development?Small children under the age of six have brains that are developing very quickly, making them vulnerable. The target organ of lead for those children is the brain, but it also interferes with every enzyme system in the body. What happens with these children with regard to blood levels is that it’s a risk factor, not a diagnosis. It shows that these children are at risk and struggling in school. They’re at risk of having poor impulse control, which affects their judgment and their ability to control emotions. Those two factors can put them on a really bad life course. Children who have blood levels above five or six micrograms per deciliter are more likely not to make the transition in school when academic performance standards change.What signs should families look for?In the third grade, children move from learning to read to reading to learn. In the eighth grade, you move from memorizing arithmetic facts to using math concepts. Children with lead in their blood can have trouble making those transitions. They’re also four times more likely to be involved with the juvenile justice system because they can’t control their impulses and they have poor judgment. They are also more likely to repeat a grade in school and less likely to graduate from high school.But I want to be very clear that this is a risk factor. If you give me a kindergarten class where everybody had a lead level of five or higher when they were two years old and another class where nobody had lead levels, I can tell you that the second kindergarten kids are, on average, doing better than the first. But that doesn’t mean that Susan, who was in the first kindergarten, is not going to MIT. There are just too many other factors that influence IQ.The thing about lead is it’s one factor we can do something about.It seems, generally speaking, that underperforming schools exist in low-income areas where lead could be present. It seems like a double blow, alongside other societal issues. Is that something you’ve seen in your research?Yeah, sure. First off, low-income rental properties are not as well maintained. It’s not in the nature of paint to remain intact. There’s peeling and the person who’s living in that unit doesn’t control the condition of the paint the way the person who owns it does. That’s number one.Number two, there certainly has been redlining and housing discrimination over years and years, which also adds to this picture. These various impacts are cumulative. If you have a disorganized family, a family where education is not a priority or a lousy school, then you add lead-in. It’s bad.There is an endpoint to how resilient a person can be.How can people protect themselves? Is there anything they can look out for in their water or on their walls that might help them identify lead?That’s a very good point. You can get a lead paint inspection. You hire somebody, and they come in with a machine and it tells you how much lead is in the paint on the wall. You can also buy test kits, usually at Home Depot or Amazon. That changes color. You just rub it and you can see that if it turns dark pink or dark blue, it’s lead paint. This is really important for people to do if they’re going to do any kind of renovation in a house because that really liberates a lot of lead.They need to know the EPA has a wonderful book, Renovate Right. That will tell people exactly how to do it or have their contractor do it.

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