Mexican Communities Are Trying to Protect an Endangered Fir Forest
By Agustín del Castillo
For 20 years, the Colima fir tree (Abies colimensis) has been at the heart of many disputes to conserve the temperate forests of southern Jalisco, a state in central Mexico. Today, the future of this tree rests upon whether the area's avocado crops will advance further and whether neighboring communities will unite to protect it.
The Colima fir tree's distribution has been reduced to the area surrounding the Nevado de Colima volcano. In November 2019, Mexican authorities included the tree on a list of endangered species.
The Nevado de Colima volcano stands 4,260 meters (13,976 feet) above sea level. Agustín del Castillo
According to biologist José Villa Castillo, the director of Nevado de Colima National Park and Nevado de Colima Cloud Forest State Park, it is imperative to stop the commercialization of the tree's timber and to create policies that conserve the forests in which it lives. Villa Castillo also supported the inclusion of the tree on the endangered species list.
Villa Castillo acknowledged the enormous challenge of conserving this tree, and he said the pressure to exploit its timber without sustainable management is far from the only problem. The expansion of the nearby avocado industry also threatens its survival.
When allowed to grow, the Colima fir tree can become monumental: It can reach 60 meters (196 feet) in height and 2 m (6.5 ft) in diameter. To protect this giant, specialists and communities often promote ecotourism and conservation projects inside the national and state parks that surround the Nevado de Colima volcano.
Fires That Clear Land for Avocado Crops
In 2012, a group of researchers from the University of Guadalajara proposed to the Secretariat of Environment and Natural Resources (SEMARNAT) the recognition of the A. colimensis as a unique species to differentiate it from the sacred fir (A. religiosa), which is the dominant fir tree in the Trans-Mexican Volcanic Belt, a collection of volcanoes in central Mexico.
The Colima fir tree "has extremely low genetic diversity; it has the lowest known genetic diversity among all the species in the Abies genus in Mesoamerica and one of the lowest among all the species of trees on the planet," according to the authors of the proposal to recognize the tree as an endangered species. The area it occupies "is very limited": just 15,002 hectares (37,071 acres), or 0.007% of the territory of Mexico.
The Nevado de Colima volcano, which stands 4,260 meters (13,976 feet) above sea level, is one of only eight peaks that exceed 4,000 m (13,123 ft) in Mexico. It is only 40 kilometers (25 miles) from the Pacific Ocean and is considered an "evolutionary island" because the ecosystems in its high-altitude areas drive unique adaptations in species and are cut off from other ecosystems by hundreds of kilometers. The Colima fir tree is an example of the area's biological differentiation, according to Libertad Arredondo, a researcher and expert on the ecology of high mountains.
The fir forests are mainly located in the middle of slopes or in ravines. Agustín del Castillo
Even though the tree has remained on that "evolutionary island," its situation has become increasingly complicated by the impact of deforestation, which was propelled by the issuance of permits for forest exploitation. Fires, started to convert the land to agriculture or other uses, also present a threat to the ecosystem, according to the experts who suggested the tree should be considered endangered.
The researchers said the tree's future prospects are further complicated by its slow growth rate, its high degree of genetic erosion, the effects of climate change, and the movement of clouds to higher altitudes. The position of clouds is crucial because they act as an essential source of moisture for fir trees.
Villa Castillo, an expert in pine genetics and reproduction, said the Colima fir tree has never been successfully reproduced in nurseries, which would likely make it impossible to conduct reforestation efforts to help repopulate the species.
The forests that contain the Colima fir tree are in cold, humid climates, with very little light reaching the understory, and they're mainly located in the middle of slopes or in ravines. The species thrives when surrounded by oak trees, coniferous trees and other types of vegetation common in mountainous cloud forests. The tree also requires a primary habitat with little disturbance from humans.
According to Villa Castillo, fire kills most Colima fir tree seedlings, as it kills seedlings of other species in the Abies genus. In recent years, more fires have been started in the forest to clear the way for avocado trees.
A tree and other vegetation in the cloud forest surrounding the Nevado de Colima volcano. Agustín del Castillo
Sonia Navarro Pérez, a researcher from the University of Guadalajara who has monitored and conducted biological inventories in the area, has seen firsthand how the growth of the avocado industry has led to the loss of important forested areas.
She described the case of the indigenous community of San José del Carmen, which is in the municipality of Zapotitlán de Vadillo, near one of the patches of forest.
"We were working with them to establish productive alternatives that are good for nature," Navarro Pérez said. "But when the avocado came, it overwhelmed us completely."
Since 2013, the coniferous forests around the Nevado de Colima volcano have lost nearly 6,600 hectares (16,300 acres) due to illegal logging, livestock rearing and intentionally set fires, according to Mexico's deforestation risk index developed by the National Institute of Ecology and Climate Change.
A section of cloud forest in San José del Carmen, inside the state park created in 2009. Community members have been protecting the forest voluntarily for over two decades. Agustín del Castillo
"[What was once] an original area of 7,000 hectares [17,300 acres] of fir-specific forest is now cut in half," said Villa Castillo, the director of the Nevado de Colima national and state parks.
The expansion of the avocado crops is the most recent threat in a series of events that have negatively impacted the conservation of the forests in the area.
Between the 1940s and the 1990s, the Atenquique Industrial Company had exclusive rights to use the timber from these forests under a concession from the Mexican government. The result was "that the forests were skimmed — that is, they took the best parts," Villa Castillo said.
When the concession expired in 1995, the forests did not experience a transition to a sustainable timber extraction method. Those who, along with landowners who held small plots, had rights to the shared land were limited to selling the forested areas, at very low prices, to the new logging industries located in Ciudad Guzmán. "Then, there were many abuses against the communities. The money was given to the caciques" — families who have always controlled the shared land — "alms were left for the community, and our forests were very poorly managed," said Rafael González Merín, the former president of Huescalapa, a collective of communally owned farmland known as an ejido.
As a result, many residents of the community believe the solution is to conserve the forests with productive projects.
Communities Pitch in to Save Their Trees
Unlike the communities that have been overtaken by the avocado industry, Huescalapa has largely managed to resist its arrival. The community of shared land, which spans more than 1,200 hectares (3,000 acres), is home to pine and fir trees within its shady temperate forests.
The residents of Huescalapa have also set aside the proposals they've received from the forestry industry, which has expressed interest in buying their trees.
According to Gerardo Bernabé Aguayo, logging activity in this area of Jalisco "has been very negative because the industry has managed delicate areas — with very limited species — poorly, so we are supporting and launching projects with the communities." Bernabé Aguayo is the president of the board of trustees of Nevado de Colima and Adjacent Basins, a civil association created about 20 years ago after being promoted by the government of the state of Jalisco. To support the conservation of the national and state parks, the board has financing from the regional private sector.
The board manages about 6 million pesos ($268,000) contributed by the federal government in 2020. With resources from the private sector, it has been able to access an additional 1.5 million pesos ($67,000).
An area of fir trees that has been destroyed by logging. Agustín del Castillo
Rodrigo Cantera Hernández, the president of the El Alcázar Ecotourism Center, said that in Huescalapa, the caciques removed timber from the fir forests, "but they did not report any money to the other community members, so we fought to eject them and were able to do so a couple of years ago."
In Huescalapa, three main conflicts over timber have taken place in the past 20 years. First, in 1999, a group of community members sold part of the forest to a forestry industry from Ciudad Guzmán. A movement led by citizens put an end to the logging five months later.
Next, in 2012, environmental authorities granted permission for forest exploitation in these areas, so fir trees continued to be cut down. An opinion by the Institute of Environmental Law, a civil society organization, cited scientific evidence that demonstrated the uniqueness of mountain fir trees and forced SEMARNAT to withdraw these permissions.
The citizens of Huescalapa formed a cooperative to launch the El Alcázar Ecotourism Center. El Alcázar Ecotourism Center
Then, in 2015, a federal judge suspended a new authorization to exploit timber in the cloud forest.
For communities like Huescalapa to have economic options that do not involve the use of timber because of the detrimental effects that this may have on the remaining population of Colima fir trees, ecotourism and similar activities are promoted.
According to Bernabé Aguayo, the goal is for the natural forest to be conserved as "a key area for contemplation, enjoyment, the preservation of environmental services, and research."
In 2019, the cooperative in El Alcázar received 1 million pesos ($44,600), which allowed it to have the basic infrastructure for the ecotourism center. The cooperative may receive an additional 3 million pesos ($133,800) in 2020 to purchase more equipment and improve the roads, but support for this funding was blocked in a community assembly. "They have not understood that it is for the benefit of everyone, that it is not money for our pockets," said Cantera Hernández, the president of the cooperative.
In Huescalapa, one of the challenges that interferes with efforts to promote the ecotourism center is the division that exists between community members. Many seek to use the timber, but others are already convinced of the importance of conservation.
Villa Castillo, the director of the Nevado de Colima national and state parks, emphasized that projects similar to the El Alcázar Ecotourism Center are being promoted in San José del Carmen and Zapotitlán de Vadillo, which are very close to the border between the states of Jalisco and Colima.
María de la Luz Cortés Reyes, the leader of the Amixtlán cooperative, which was created in San José del Carmen. Agustín del Castillo
The Amixtlán Ecotourism Center is located in the community of San José del Carmen. A cluster of cabins marks the entrance to the cloud forest, designated a state park since 2009.
"We decided to protect our forest long before they declared the state park, 20 years before then," said María de la Luz Cortés Reyes, a community leader in San José del Carmen. She recalled that when loggers came with offers to buy the forest, members of the community believed that they offered very little payment and that "the damage [that the loggers left] was too much." For that reason, they decided "not to touch the forest, because it produces water for the crops and for our houses."
Cortés Reyes said the community was able to construct the ecotourism center because it had resources managed by the Nevado de Colima Cloud Forest State Park and by the Board of Trustees of Nevado de Colima and Adjacent Basins. However, she said it is important that more promotion is given to the area and that urgent problems, such as those with the water supply system, are resolved.
A view of the Nevado de Colima volcano from the Amixtlán Ecotourism Center in San José del Carmen. Agustín del Castillo
In the community of Zapotitlán de Vadillo, citizens also promoted the Puerta de la Hacienda Ecotourism Center, where administrators support the biocultural production of mezcal, an alcoholic beverage made from agave. The drink is made by two mezcaleros, or people who are experts in creating mezcal: Marcario Partida from Zapotitlán de Vadillo, and Rosario Pineda from Tetapán, a small community in Zapotitlán de Vadillo.
Other productive projects that are promoted in the communities include the organic production of eggs, such as by Efigenia Larios, a small producer from the community of El Tecuán. Additionally, the shared land communities of Zapotitlán de Vadillo, San José del Carmen and Huescalapa are provided with equipment for fire prevention and materials to help restore the forest soil.
Artists have painted murals that shine a spotlight on forest conservation in San José del Carmen and Zapotitlán de Vadillo.
The intention of these efforts is to allow those who own land or have rights on this fragile mountain to "understand that there are other options besides logging, and that they, too, can generate development," said Arredondo, the researcher who specializes in the ecology of high mountains.
Despite the strong pressure for land use changes brought by the avocado agroindustry and fostered by the high level of impunity that often prevails in rural areas, many of the area's landowners continue to search for a model in which their forests can remain standing.
"Many neighbors say that we are foolish for not wanting to sell this beautiful forest that we have, but that money only lasts for a short time," said José Avalo Lino, a farmer in San José del Carmen. "We are so certain of [the importance of] preventing logging that, long before the declaration of the natural protected area, our community assembly had already decided to save this forest. We will continue to be 'foolish' in this decision."
Reposted with permission from Mongabay.
By Frank La Sorte and Kyle Horton
Millions of birds travel between their breeding and wintering grounds during spring and autumn migration, creating one of the greatest spectacles of the natural world. These journeys often span incredible distances. For example, the Blackpoll warbler, which weighs less than half an ounce, may travel up to 1,500 miles between its nesting grounds in Canada and its wintering grounds in the Caribbean and South America.
Blackpoll warbler. PJTurgeon / Wikipedia<p>We used this information to determine how the number of migratory bird species varies based on each city's level of <a href="https://www.britannica.com/science/light-pollution" target="_blank" rel="noopener noreferrer">light pollution</a> – brightening of the night sky caused by artificial light sources, such as buildings and streetlights. We also explored how species numbers vary based on the quantity of tree canopy cover and impervious surface, such as concrete and asphalt, within each city. Our findings show that cities can help migrating birds by planting more trees and reducing light pollution, especially during spring and autumn migration.</p>
Declining Bird Populations<p>Urban areas contain numerous dangers for migratory birds. The biggest threat is the risk of <a href="https://doi.org/10.1650/CONDOR-13-090.1" target="_blank">colliding with buildings or communication towers</a>. Many migratory bird populations have <a href="http://dx.doi.org/10.1126/science.aaw1313" target="_blank">declined over the past 50 years</a>, and it is possible that light pollution from cities is contributing to these losses.</p><p>Scientists widely agree that light pollution can <a href="https://doi.org/10.1073/pnas.1708574114" target="_blank">severely disorient migratory birds</a> and make it hard for them to navigate. Studies have shown that birds will cluster around brightly lit structures, much like insects flying around a porch light at night. Cities are the <a href="https://doi.org/10.1002/fee.2029" target="_blank" rel="noopener noreferrer">primary source of light pollution for migratory birds</a>, and these species tend to be more abundant within cities <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13792" target="_blank" rel="noopener noreferrer">during migration</a>, especially in <a href="https://doi.org/10.1016/j.landurbplan.2020.103892" target="_blank" rel="noopener noreferrer">city parks</a>.</p>
Composite image of the continental U.S. at night from satellite photos. NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center
The Power of Citizen Science<p>It's not easy to observe and document bird migration, especially for species that migrate at night. The main challenge is that many of these species are very small, which limits scientists' ability to use electronic tracking devices.</p><p>With the growth of the internet and other information technologies, new data resources are becoming available that are making it possible to overcome some of these challenges. <a href="https://doi.org/10.1038/d41586-018-07106-5" target="_blank">Citizen science initiatives</a> in which volunteers use online portals to enter their observations of the natural world have become an important resource for researchers.</p><p>One such initiative, <a href="https://ebird.org/home" target="_blank" rel="noopener noreferrer">eBird</a>, allows bird-watchers around the globe to share their observations from any location and time. This has produced one of the <a href="https://doi.org/10.1111/ecog.04632" target="_blank" rel="noopener noreferrer">largest ecological citizen-science databases in the world</a>. To date, eBird contains over 922 million bird observations compiled by over 617,000 participants.</p>
Light Pollution Both Attracts and Repels Migratory Birds<p>Migratory bird species have evolved to use certain migration routes and types of habitat, such as forests, grasslands or marshes. While humans may enjoy seeing migratory birds appear in urban areas, it's generally not good for bird populations. In addition to the many hazards that exist in urban areas, cities typically lack the food resources and cover that birds need during migration or when raising their young. As scientists, we're concerned when we see evidence that migratory birds are being drawn away from their traditional migration routes and natural habitats.</p><p>Through our analysis of eBird data, we found that cities contained the greatest numbers of migratory bird species during spring and autumn migration. Higher levels of light pollution were associated with more species during migration – evidence that light pollution attracts migratory birds to cities across the U.S. This is cause for concern, as it shows that the influence of light pollution on migratory behavior is strong enough to increase the number of species that would normally be found in urban areas.</p><p>In contrast, we found that higher levels of light pollution were associated with fewer migratory bird species during the summer and winter. This is likely due to the scarcity of suitable habitat in cities, such as large forest patches, in combination with the adverse affects of light pollution on bird behavior and health. In addition, during these seasons, migratory birds are active only during the day and their populations are largely stationary, creating few opportunities for light pollution to attract them to urban areas.</p>
Trees and Pavement<p>We found that tree canopy cover was associated with more migratory bird species during spring migration and the summer. Trees provide important habitat for migratory birds during migration and the breeding season, so the presence of trees can have a strong effect on the number of migratory bird species that occur in cities.</p><p>Finally, we found that higher levels of impervious surface were associated with more migratory bird species during the winter. This result is somewhat surprising. It could be a product of the <a href="https://www.epa.gov/heatislands" target="_blank">urban heat island effect</a> – the fact that structures and paved surfaces in cities absorb and reemit more of the sun's heat than natural surfaces. Replacing vegetation with buildings, roads and parking lots can therefore make cities significantly warmer than surrounding lands. This effect could reduce cold stress on birds and increase food resources, such as insect populations, during the winter.</p><p>Our research adds to our understanding of how conditions in cities can both help and hurt migratory bird populations. We hope that our findings will inform urban planning initiatives and strategies to reduce the harmful effects of cities on migratory birds through such measures as <a href="https://www.arborday.org/programs/treecityusa/index.cfm" target="_blank" rel="noopener noreferrer">planting more trees</a> and initiating <a href="https://aeroecolab.com/uslights" target="_blank" rel="noopener noreferrer">lights-out programs</a>. Efforts to make it easier for migratory birds to complete their incredible journeys will help maintain their populations into the future.</p><p><em><span style="background-color: initial;"><a href="https://theconversation.com/profiles/frank-la-sorte-1191494" target="_blank">Frank La Sorte</a> is a r</span>esearch associate at the </em><em>Cornell Lab of Ornithology, Cornell University. <a href="https://theconversation.com/profiles/kyle-horton-1191498" target="_blank">Kyle Horton</a> is an assistant professor of Fish, Wildlife, and Conservation Biology at the Colorado State University.</em></p><p><em></em><em>Disclosure statement: Frank La Sorte receives funding from The Wolf Creek Charitable Foundation and the National Science Foundation (DBI-1939187). K</em><em>yle Horton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</em></p><p><em>Reposted with permission from <a href="https://theconversation.com/cities-can-help-migrating-birds-on-their-way-by-planting-more-trees-and-turning-lights-off-at-night-152573" target="_blank">The Conversation</a>. </em></p>
EcoWatch Daily Newsletter
By Lynne Peeples
Editor's note: This story is part of a nine-month investigation of drinking water contamination across the U.S. The series is supported by funding from the Park Foundation and Water Foundation. Read the launch story, "Thirsting for Solutions," here.
In late September 2020, officials in Wrangell, Alaska, warned residents who were elderly, pregnant or had health problems to avoid drinking the city's tap water — unless they could filter it on their own.
Unintended Consequences<p>Chemists first discovered disinfection by-products in treated drinking water in the 1970s. The trihalomethanes they found, they determined, had resulted from the reaction of chlorine with natural organic matter. Since then, scientists have identified more than 700 additional disinfection by-products. "And those only represent a portion. We still don't know half of them," says Richardson, whose lab has identified hundreds of disinfection by-products. </p>
What’s Regulated and What’s Not?<p>The U.S. Environmental Protection Agency (EPA) currently regulates 11 disinfection by-products — including a handful of trihalomethanes (THM) and haloacetic acids (HAA). While these represent only a small fraction of all disinfection by-products, EPA aims to use their presence to indicate the presence of other disinfection by-products. "The general idea is if you control THMs and HAAs, you implicitly or by default control everything else as well," says Korshin.</p><p>EPA also requires drinking water facilities to use techniques to reduce the concentration of organic materials before applying disinfectants, and regulates the quantity of disinfectants that systems use. These rules ultimately can help control levels of disinfection by-products in drinking water.</p>
Click the image for an interactive version of this chart on the Environmental Working Group website.<p>Still, some scientists and advocates argue that current regulations do not go far enough to protect the public. Many question whether the government is regulating the right disinfection by-products, and if water systems are doing enough to reduce disinfection by-products. EPA is now seeking public input as it considers potential revisions to regulations, including the possibility of regulating additional by-products. The agency held a <a href="https://www.epa.gov/dwsixyearreview/potential-revisions-microbial-and-disinfection-byproducts-rules" target="_blank">two-day public meeting</a> in October 2020 and plans to hold additional public meetings throughout 2021.</p><p>When EPA set regulations on disinfection by-products between the 1970s and early 2000s, the agency, as well as the scientific community, was primarily focused on by-products of reactions between organics and chlorine — historically the most common drinking water disinfectant. But the science has become increasingly clear that these chlorinated chemicals represent a fraction of the by-product problem.</p><p>For example, bromide or iodide can get caught up in the reaction, too. This is common where seawater penetrates a drinking water source. By itself, bromide is innocuous, says Korshin. "But it is extremely [reactive] with organics," he says. "As bromide levels increase with normal treatment, then concentrations of brominated disinfection by-products will increase quite rapidly."</p><p><a href="https://pubmed.ncbi.nlm.nih.gov/15487777/" target="_blank">Emerging</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b05440" target="_blank" rel="noopener noreferrer">data</a> indicate that brominated and iodinated by-products are potentially more harmful than the regulated by-products.</p><p>Almost half of the U.S. population lives within 50 miles of either the Atlantic or Pacific coasts, where saltwater intrusion can be a problem for drinking water supplies. "In the U.S., the rule of thumb is the closer to the sea, the more bromide you have," says Korshin, noting there are also places where bromide naturally leaches out from the soil. Still, some coastal areas tend to be spared. For example, the city of Seattle's water comes from the mountains, never making contact with seawater and tending to pick up minimal organic matter.</p><p>Hazardous disinfection by-products can also be an issue with desalination for drinking water. "As <a href="https://ensia.com/features/can-saltwater-quench-our-growing-thirst/" target="_blank" rel="noopener noreferrer">desalination</a> practices become more economical, then the issue of controlling bromide becomes quite important," adds Korshin.</p>
Other Hot Spots<p>Coastal areas represent just one type of hot spot for disinfection by-products. Agricultural regions tend to send organic matter — such as fertilizer and animal waste — into waterways. Areas with warmer climates generally have higher levels of natural organic matter. And nearly any urban area can be prone to stormwater runoff or combined sewer overflows, which can contain rainwater as well as untreated human waste, industrial wastewater, hazardous materials and organic debris. These events are especially common along the East Coast, notes Sydney Evans, a science analyst with the nonprofit Environmental Working Group (EWG, a collaborator on <a href="https://ensia.com/ensia-collections/troubled-waters/" target="_blank">this reporting project</a>).</p><p>The only drinking water sources that might be altogether free of disinfection by-products, suggests Richardson, are private wells that are not treated with disinfectants. She used to drink water from her own well. "It was always cold, coming from great depth through clay and granite," she says. "It was fabulous."</p><p>Today, Richardson gets her water from a city system that uses chloramine.</p>
Toxic Treadmill<p>Most community water systems in the U.S. use chlorine for disinfection in their treatment plant. Because disinfectants are needed to prevent bacteria growth as the water travels to the homes at the ends of the distribution lines, sometimes a second round of disinfection is also added in the pipes.</p><p>Here, systems usually opt for either chlorine or chloramine. "Chloramination is more long-lasting and does not form as many disinfection by-products through the system," says Steve Via, director of federal relations at the American Water Works Association. "Some studies show that chloramination may be more protective against organisms that inhabit biofilms such as Legionella."</p>
Alternative Approaches<p>When he moved to the U.S. from Germany, Prasse says he immediately noticed the bad taste of the water. "You can taste the chlorine here. That's not the case in Germany," he says.</p><p>In his home country, water systems use chlorine — if at all — at lower concentrations and at the very end of treatment. In the Netherlands, <a href="https://dwes.copernicus.org/articles/2/1/2009/dwes-2-1-2009.pdf" target="_blank">chlorine isn't used at all</a> as the risks are considered to outweigh the benefits, says Prasse. He notes the challenge in making a convincing connection between exposure to low concentrations of disinfection by-products and health effects, such as cancer, that can occur decades later. In contrast, exposure to a pathogen can make someone sick very quickly.</p><p>But many countries in Europe have not waited for proof and have taken a precautionary approach to reduce potential risk. The emphasis there is on alternative approaches for primary disinfection such as ozone or <a href="https://www.pbs.org/wgbh/nova/article/eco-friendly-way-disinfect-water-using-light/" target="_blank" rel="noopener noreferrer">ultraviolet light</a>. Reverse osmosis is among the "high-end" options, used to remove organic and inorganics from the water. While expensive, says Prasse, the method of forcing water through a semipermeable membrane is growing in popularity for systems that want to reuse wastewater for drinking water purposes.</p><p>Remucal notes that some treatment technologies may be good at removing a particular type of contaminant while being ineffective at removing another. "We need to think about the whole soup when we think about treatment," she says. What's more, Remucal explains, the mixture of contaminants may impact the body differently than any one chemical on its own. </p><p>Richardson's preferred treatment method is filtering the water with granulated activated carbon, followed by a low dose of chlorine.</p><p>Granulated activated carbon is essentially the same stuff that's in a household filter. (EWG recommends that consumers use a <a href="https://www.ewg.org/tapwater/reviewed-disinfection-byproducts.php#:~:text=EWG%20recommends%20using%20a%20home,as%20trihalomethanes%20and%20haloacetic%20acids." target="_blank" rel="noopener noreferrer">countertop carbon filter</a> to reduce levels of disinfection by-products.) While such a filter "would remove disinfection by-products after they're formed, in the plant they remove precursors before they form by-products," explains Richardson. She coauthored a <a href="https://pubs.acs.org/doi/10.1021/acs.est.9b00023" target="_blank" rel="noopener noreferrer">2019 paper</a> that concluded the treatment method is effective in reducing a wide range of regulated and unregulated disinfection by-products.</p><br>
Greater Cincinnati Water Works installed a granulated activated carbon system in 1992, and is still one of relatively few full-scale plants that uses the technology. Courtesy of Greater Cincinnati Water Works.<p>Despite the technology and its benefits being known for decades, relatively few full-scale plants use granulated active carbon. They often cite its high cost, Richardson says. "They say that, but the city of Cincinnati [Ohio] has not gone bankrupt using it," she says. "So, I'm not buying that argument anymore."</p><p>Greater Cincinnati Water Works installed a granulated activated carbon system in 1992. On a video call in December, Jeff Swertfeger, the superintendent of Greater Cincinnati Water Works, poured grains of what looks like black sand out of a glass tube and into his hand. It was actually crushed coal that has been baked in a furnace. Under a microscope, each grain looks like a sponge, said Swertfeger. When water passes over the carbon grains, he explained, open tunnels and pores provide extensive surface area to absorb contaminants.</p><p>While the granulated activated carbon initially was installed to address chemical spills and other industrial contamination concerns in the Ohio River, Cincinnati's main drinking water source, Swertfeger notes that the substance has turned out to "remove a lot of other stuff, too," including <a href="https://ensia.com/features/drinking-water-contamination-pfas-health/" target="_blank" rel="noopener noreferrer">PFAS</a> and disinfection by-product precursors.</p><p>"We use about one-third the amount of chlorine as we did before. It smells and tastes a lot better," he says. "The use of granulated activated carbon has resulted in lower disinfection by-products across the board."</p><p>Richardson is optimistic about being able to reduce risks from disinfection by-products in the future. "If we're smart, we can still kill those pathogens and lower our chemical disinfection by-product exposure at the same time," she says.</p><p><em>Reposted with permission from </em><em><a href="https://ensia.com/features/drinking-water-disinfection-byproducts-pathogens/" target="_blank">Ensia</a>. </em><a href="https://www.ecowatch.com/r/entryeditor/2649953730#/" target="_self"></a></p>
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