Category: Environmental Effects

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Martian Dust Could be a Health Hazard to Future Astronauts

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Don’t breathe in the dust on Mars.

That’s the takeaway from new research from a team of scientists, including researchers from the University of Colorado Boulder. The findings suggests that long-term exposure to Martian dust could create a host of health problems for future astronauts – leading to chronic respiratory problems, thyroid disease and more.

The study, published in the journal GeoHealth, is the first to take a comprehensive look at the chemical ingredients that make up Martian dust, and their possible impacts on human health. It was undertaken by a team from the worlds of medicine, geology and aerospace engineering.

“This isn’t the most dangerous part about going to Mars,” said Justin Wang, lead author of the study and a student in the Keck School of Medicine at the University of Southern California in Los Angeles. “But dust is a solvable problem, and it’s worth putting in the effort to develop Mars-focused technologies for preventing these health problems in the first place.”

Wang, a CU Boulder alumnus, noted that Apollo era astronauts experienced runny eyes and irritated throats after inhaling dust from the moon. Apollo 17’s Harrison Schmitt likened the symptoms to hay fever.

But scientists know a lot less about the potential harms of Martian dust. To begin to answer that question, Wang and his colleagues drew on data from rovers on Mars and even Martian meteorites to better understand what makes up the planet’s dust. The group discovered a “laundry list” of chemical compounds that could be dangerous for people—at least when inhaled in large quantities and over long periods of time.

They include minerals rich in silicates and iron oxides, metals like beryllium and arsenic and a particularly nasty class of compounds called perchlorates.

In many cases, those ingredients are present in only trace amounts in Mars dust. But the first human explorers on Mars may spend around a year and a half on the surface, increasing their exposure, said study co-author Brian Hynek.

“You’re going to get dust on your spacesuits, and you’re going to have to deal with regular dust storms,” said Hynek, a geologist at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder. “We really need to characterize this dust so that we know what the hazards are.”

Into the bloodstream

One thing is clear, he added: Mars is a dusty place.

Much of the planet is covered in a thick layer of dust rich in tiny particles of iron, which gives the planet its famous red colour. Swirling dust storms are common and, in some cases, can engulf the entire globe.

“We think there could be 10 metres of dust sitting on top of the bigger volcanoes,” said Hynek, a professor in the Department of Geological Sciences. “If you tried to land a spacecraft there, you’re going to just sink into the dust.”

Wang found his own way to Martian dust through a unique academic path. He started medical school after earning bachelor’s degrees from CU Boulder in astronomy and molecular, cellular and developmental biology, followed by a master’s degree in aerospace engineering sciences. He currently serves in the Navy through its Health Professions Scholarship Program.

He noted that the biggest problem with Martian dust comes down to its size. Estimates suggest that the average size of dust grains on Mars may be as little as 3 micrometers across, or roughly one-ten-thousandth of an inch.

“That’s smaller than what the mucus in our lungs can expel,” Wang said. “So after we inhale Martian dust, a lot of it could remain in our lungs and be absorbed into our blood stream.”

An ounce of prevention

In the current study, Wang and several of his fellow medical students at USC scoured research papers to unearth the potential toxicological effects of the ingredients in Martian dust.

Some of what they found resembled common health problems on Earth. Dust on Mars, for example, contains large amounts of the compound silica, which is abundant in minerals on our own planet. People who inhale a lot of silica, such as glass blowers, can develop a condition known as silicosis. Their lung tissue becomes scarred, making it hard to breath—symptoms similar to the “black lung” disease that coal miners often contract. Currently, there is no cure for silicosis.

In other cases, the potential health consequences are much less well-known.

Martian dust carries large quantities of highly oxidising compounds called perchlorates, which are made up of one chlorine and multiple oxygen atoms. Perchlorates are rare on Earth, but some evidence suggests that they can interfere with human thyroid function, leading to severe anaemia. Even inhaling a few milligrams of perchlorates in Martian dust could be dangerous for astronauts.

Wang noted that the best time to prepare for the health risks of Martian dust is before humans ever make it to the planet. Iodine supplements, for example, would boost astronauts’ thyroid function, potentially counteracting the toll of perchlorates – although taking too much iodine can also, paradoxically, lead to thyroid disease. Filters specifically designed to screen out Martian dust could also help to keep the air in living spaces clean.

“Prevention is key. We tell everyone to go see their primary care provider to check your cholesterol before it gives you a heart attack,” Wang said. “The best thing we can do on Mars is make sure the astronauts aren’t exposed to dust in the first place.”

Source: University of Colorado at Boulder

Categories : Allergies Environmental EffectsTags :

How is Climate Change Affecting Seasonal Allergies?

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A review published in The Laryngoscope indicates that climate change’s effects on pollen seasons and concentrations are contributing to increasing rates of allergic rhinitis.

When investigators assessed research published between 2000 and 2023, they identified 30 studies that reported on the current epidemiological state of allergic rhinitis, described factors related to climate change, and observed how global warming is affecting pollen seasons and allergy symptoms.

Sixteen studies reported longer pollen seasons and/or higher pollen concentrations related to climate change. As an example, total pollen emissions in the U.S. are projected to increase by 16–40% by the end of the century and pollen season length to increase by 19 days. Four studies reported an increase in allergic rhinitis–related health care usage, particularly among low-income residents. Two studies reported that health care professionals want more education on climate change. 

“Physicians are uniquely positioned to witness the impact of allergic rhinitis on patient outcomes and can adapt their practice as climate change intensifies,” said corresponding author Alisha R. Pershad, BS, a third-year medical student at the George Washington University School of Medicine and Health Sciences. “As trusted voices in the community, they should leverage their frontline experience to advocate for meaningful change in addressing the climate crisis.”

Source: Wiley

Categories : Cardiovascular Disease Environmental EffectsTags :

Cardiovascular Disease Deaths Worldwide Linked to Widely Used Phthalates

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Phthalates are commonly used in plastic medical equipment

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Daily exposure to certain chemicals used to make plastic household items could be linked to the more than 356 000 global deaths from cardiovascular disease that occurred in 2018 alone, a new analysis of population surveys shows.

Although the chemicals, called phthalates, are in widespread use globally, the Middle East, South Asia, East Asia, and the Pacific bore a much larger share of the death toll than others – about three-fourths of the total.

For decades, experts have connected health problems to exposure to certain phthalates found in cosmetics, detergents, solvents, plastic pipes, bug repellents, and other products. These chemicals break down into microscopic particles and are ingested, and studies have linked such exposure to an increased risk of conditions ranging from obesity and diabetes to fertility issues and cancer.

Led by researchers at NYU Langone Health and published in eBioMedicine, the current study focused on a kind of phthalate called di-2-ethylhexyl phthalate (DEHP). This chemical is used to increase the flexibility and softness of food containers, medical equipment, and other plastic items. Exposure has been shown in other studies to prompt inflammation in the heart’s arteries, which over time is associated with increased risk of heart attack or stroke. In their new analysis, the authors estimated that DEHP exposure contributed to 356 238 deaths, or more than 13% of all global mortality from heart disease in 2018 among men and women ages 55 through 64.

“By highlighting the connection between phthalates and a leading cause of death across the world, our findings add to the vast body of evidence that these chemicals present a tremendous danger to human health,” said study lead author Sara Hyman, BS, an associate research scientist at NYU Grossman School of Medicine.

In a past study from 2021, the research team tied phthalates to more than 50 000 premature deaths each year, mostly from heart disease, among older Americans. Their latest investigation is believed to be the first global estimate to date of cardiovascular mortality, or indeed any health outcome, resulting from exposure to the chemicals, said Hyman, who is also a graduate student at NYU School of Global Public Health.

For the research, the team used health and environmental data from dozens of population surveys to estimate DEHP exposure across 200 countries and territories. The information included urine samples containing chemical breakdown products left by the plastic additive. Mortality data was obtained from the Institute for Health Metrics and Evaluation, a research group in the United States that collects medical information worldwide to identify trends in public health.

Among the key findings, the study showed that losses in the combined region of East Asia and the Middle East and the combined region of East Asia and the Pacific accounted, respectively, for about 42% and 32% of the mortality from ardiovascular disease linked to DEHP. Specifically, India had the highest death count, at 103 587 deaths, followed by China and Indonesia. The larger heart death risks in these populations held true even after the researchers adjusted their statistical analysis to take into account population size within the studied age group.

A possible explanation, the authors say, is that these countries face higher rates of exposure to the chemicals, possibly because they are undergoing a boom in plastic production but with fewer manufacturing restrictions than other regions.

“There is a clear disparity in which parts of the world bear the brunt of heightened heart risks from phthalates,” said study senior author Leonardo Trasande, MD, MPP. “Our results underscore the urgent need for global regulations to reduce exposure to these toxins, especially in areas most affected by rapid industrialisation and plastic consumption,” added Dr Trasande, Professor of Pediatrics at NYU Grossman School of Medicine.

Dr Trasande, who is also a professor in the Department of Population Health, cautions that the analysis was not designed to establish that DEHP directly or alone caused heart disease and that higher death risks did not take into account other types of phthalates. Nor did it include mortality among those in other age groups. As a result, the overall death toll from heart disease connected to these chemicals is likely much higher, he says.

Dr Trasande says that the researchers next plan to track how reductions in phthalate exposure may, over time, affect global mortality rates, as well as to expand the study to other health concerns posed by the chemicals, such as preterm birth.

Source: NYU Langone Health / NYU Grossman School of Medicine

Categories : Environmental Effects Mental HealthTags :

Nature-based Activity is Effective Therapy for Anxiety and Depression, Study Shows

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A prescription of gardening an allotment in the UK has shown promise as a means of improving health and well-being outside of conventional medical treatments. 

Green social prescribing is a practice whereby a healthcare professional refers a patient to community-based nature activities to help improve health and well-being beyond medical treatments. Currently these programmes are in a testing phase, but evidence is now pointing to the need for investment in this area to make it an additional option for patients across the country.

More than 220 participants were included in the programme, and their mental health status was evaluated before and after exposure to an organised programme of nature-based activities, such as horticultural and care farming, sport and exercise, and outdoor mindfulness and craft-based activities.

The majority of participants took part in the programme weekly between one and four weeks, five to eight weeks, and others between nine and 12 weeks.  The team used the Office of National Statistics  measures of personal well-being, as well as the hospital anxiety and depression scale (HADS) to understand if participants had made improvements.

Horticulture

Across the board, participants reported improvements in well-being and mental health. But participants in longer programmes – typically nine to 12 weeks – or took part in activities related to horticulture and care farming, showed greater improvements in mood and anxiety levels compared with those involved in shorter programmes – one to four weeks – or in activities such as outdoor crafts, creative and mindfulness-based sessions, or sport and exercise.

The signs of improvement were similar to those seen in short-term cognitive behavioural therapy (CBT), where someone might meet one-to-one with a therapist over a period ranging from six weeks to a year or more.

Professor Peter Coventry, Director of the University’s Mental Health and Addiction Research Group, said: “We have known for some time that nature has a positive impact on health and wellbeing, but in more recent years, a stronger evidence-base has grown that proves this to be true for mental health in particular.

“The fact that activities such as gardening, tending allotments, and care farming had the most impact on the participants in our study, demonstrated that it is not just about being passive in nature, but connecting with it in a meaningful way.  

“There is also something to be said for connecting with nature in the company of other people who live in the same place as you.  Anxiety and depression can often be born out of loneliness and feelings of disconnectedness, so it makes sense that taking part in shared activities close to home  – especially those that involve caring for and improving your local environment – can help lift mood and reduce anxiety.”

All ages

The study showed that these positive impacts were seen in all ages, which ranged from age 18 to age 85, and across genders.  Researchers are now calling for more investment to be made to support these community activities and the employment of green social prescribers that GPs and other health and social care professionals can refer their patients to.

Trish Darcy, research associate from the University’s Mental Health and Addiction Research Group, said: “This intervention might not work for everyone, but through an initial exploratory conversation a social prescriber will discuss with a patient or user of the service if nature-based activities would be suited to them, and for that choice to happen we need more investment to support these community-based activities”. 

“In our study 65% of participants were from low socioeconomic groups and we now know that not only can it help improve their mental health, but participation was high for  horticultural based activities in particular, meaning that not only is it good for the individual, but for the local community environment too.”

Test and learn

The evaluation, published in the journal Health & Social Care in the Community, was conducted in partnership with The HEY Smile Foundation and NHS Humber and North Yorkshire Integrated Care Board (ICB).

Dr Hannah Armitt a Clinical Psychologist and Clinical Lead for the Humber and North Yorkshire ‘test and learn’ programme said: “The research conducted in our region has the potential to enhance service delivery by connecting statutory services with local providers of nature based and outdoors activities. 

“It is important to evidence the potential of green space and nature to ensure clinicians and patients alike can harness the benefits of this wonderful free natural resource we have in abundance in Yorkshire and Humber.”

Positive outcomes

Anthony Hurd, Humber and North Yorkshire Green Social Prescribing Programme Manager, said “This work has not only shown the positive outcomes that nature-based activities have on mental health, it has also highlighted the role that community-based organisations play in supporting the health and wellbeing of communities. 

“As healthcare begins to move more into the community, and with a focus on prevention, the community-based organisations delivering activities such as gardening, care farming and walking groups need to be recognised as key players in our national health service and be resourced appropriately.”

Source: University of York

Categories : Environmental EffectsTags :

Heat Levels That Humans can Tolerate are Lower than Previously Thought

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A study from the University of Ottawa’s Human and Environmental Physiology Research Unit (HEPRU) has confirmed that the limits for human thermoregulation – the ability to maintain a stable body temperature in extreme heat – are lower than previously thought.

This research, led by Dr Robert D. Meade, former Senior Postdoctoral Fellow and Dr Glen Kenny, Director of HEPRU and professor of physiology, highlights the urgent need to address the impacts of climate change on human health.

The study, published in the journal PNAS, found that many regions may soon experience heat and humidity levels that exceed the safe limits for human survival. “Our research provided important data supporting recent suggestions that the conditions under which humans can effectively regulate their body temperature are actually much lower than earlier models suggested,” states Kenny. “This is critical information as we face increasing global temperatures.”

Utilizing a widely used technique known as thermal-step protocols, Meade and his team exposed 12 volunteers to various heat and humidity conditions to identify the point at which thermoregulation becomes impossible. What made this study different, was that participants returned to the laboratory for a daylong exposure to conditions just above their estimated limit for thermoregulation. Participants were subjected to extreme conditions, 42°C with 57% humidity, representing a humidex of approximately 62°C. “The results were clear. The participants’ core temperature streamed upwards unabated, and many participants were unable to finish the 9-hour exposure. These data provide the first direct validation of thermal step protocols, which have been used to estimate upper limits for thermoregulation for nearly 50 years”, says Meade.

“Our findings especially timely, given estimated limits for thermoregulation are being increasingly incorporated into large scale climate modelling,” explains Meade. “They also underscore the physiological strain experienced during prolonged exposure to extreme heat, which is becoming more common due to climate change.”

The implications of this research extend beyond academia. As cities prepare for hotter summers, understanding these limits can help guide health policies and public safety measures. “By integrating physiological data with climate models, we hope to better predict and prepare for heat-related health issues,” adds Kenny.

As the world grapples with the realities of climate change, this research aims to spark important conversations about our safety and adaptability in increasingly extreme environments.

Source: University of Ottawa

Categories : Environmental EffectsTags :

Cold Plunges Fire up Repair Functions in Cells

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Investigating the effects of trendy ice baths, scientists at the University of Ottawa have made an interesting discovery on the beneficial way they affect cell functions, and have published their findings in Advanced Biology.

A new study conducted at the Human and Environmental Physiology Research lab (HEPRU) at the University of Ottawa has unveiled significant findings on the effects of cold water acclimation on autophagic (the cells’ recycling system, which promotes cellular health) and apoptotic (the programmed cell death that gets rid of damaged cells) responses in young males. The research highlights the potential for cold exposure to enhance cellular resilience against stress.

The study, conducted by Kelli King, postdoctoral fellow, and Glen Kenny, Full Professor at uOttawa’s School of Human Kinetics and Director of HEPRU, involved ten healthy young males who underwent cold-water immersion at 14°C for one hour across seven consecutive days. Blood samples were collected to analyse the participants’ cellular responses before and after the acclimation period.

“Our findings indicate that repeated cold exposure significantly improves autophagic function, a critical cellular protective mechanism,” says Professor Kenny. “This enhancement allows cells to better manage stress and could have important implications for health and longevity.”

The research revealed that while autophagy was initially dysfunctional after high-intensity cold stress, consistent exposure over a week led to increased autophagic activity and decreased cellular damage signals.

“By the end of the acclimation, we noted a marked improvement in the participants’ cellular cold tolerance,” explains King, the study’s first author. “This suggests that cold acclimation may help the body effectively cope with extreme environmental conditions.”

The implications of this study extend beyond athletic performance. Cold water immersion has gained popularity for its potential health benefits, and this research provides some scientific backing for its efficacy. The findings suggest that proper autophagic activity could not only extend cellular longevity but also prevent the onset of various diseases.

As the use of cold exposure becomes increasingly mainstream, understanding its effects on cellular mechanisms is vital. Professor Kenny emphasises, “This work underscores the importance of acclimation protocols in enhancing human health, especially in contexts where individuals are exposed to extreme temperatures.”

“We were amazed to see how quickly the body adapted,” notes King. “Cold exposure might help prevent diseases and potentially even slow down aging at a cellular level. It’s like a tune-up for your body’s microscopic machinery.”

These results apply to young males and more research is needed to see if it would also apply to other cohorts.

Source: University of Ottawa

Categories : Environmental EffectsTags :

New Evidence for a Chronic Disease Link with Microplastics

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Tiny fragments of plastic have become ubiquitous in our environment and our bodies. Higher exposure to these microplastics, which can be inadvertently consumed or inhaled, is associated with a heightened prevalence of chronic noncommunicable diseases, according to new research being presented at the American College of Cardiology’s Annual Scientific Session (ACC.25).

Researchers said the new findings add to a small but growing body of evidence that microplastic pollution represents an emerging health threat. In terms of its relationship with stroke risk, for example, microplastics concentration was comparable to factors such as minority race and lack of health insurance, according to the results.

“This study provides initial evidence that microplastics exposure has an impact on cardiovascular health, especially chronic, noncommunicable conditions like high blood pressure, diabetes and stroke,” said Sai Rahul Ponnana, MA, a research data scientist at Case Western Reserve School of Medicine in Ohio and the study’s lead author. “When we included 154 different socioeconomic and environmental features in our analysis, we didn’t expect microplastics to rank in the top 10 for predicting chronic noncommunicable disease prevalence.”

Microplastics—defined as fragments of plastic between 1 nanometre and 5 millimetres across—are released as larger pieces of plastic break down. They come from many different sources, such as food and beverage packaging, consumer products and building materials. People can be exposed to microplastics in the water they drink, the food they eat and the air they breathe.

The study examines associations between the concentration of microplastics in bodies of water and the prevalence of various health conditions in communities along the East, West and Gulf Coasts, as well as some lakeshores, in the United States between 2015-2019. While inland areas also contain microplastics pollution, researchers focused on lakes and coastlines because microplastics concentrations are better documented in these areas. They used a dataset covering 555 census tracts from the National Centers for Environmental Information that classified microplastics concentration in seafloor sediments as low (zero to 200 particles per square meter) to very high (over 40 000 particles per square metre). 

The researchers assessed rates of high blood pressure, diabetes, stroke and cancer in the same census tracts in 2019 using data from the U.S. Centers for Disease Control and Prevention. They also used a machine learning model to predict the prevalence of these conditions based on patterns in the data and to compare the associations observed with microplastics concentration to linkages with 154 other social and environmental factors such as median household income, employment rate and particulate matter air pollution in the same areas.

The results revealed that microplastics concentration was positively correlated with high blood pressure, diabetes and stroke, while cancer was not consistently linked with microplastics pollution. The results also suggested a dose relationship, in which higher concentrations of microplastic pollution are associated with a higher prevalence of disease. However, researchers said that evidence of an association does not necessarily mean that microplastics are causing these health problems. More studies are required to determine whether there is a causal relationship or if this pollution is occurring alongside another factor that leads to health issues, they said.

Further research is also needed to determine the amount of exposure or the length of time it might take for microplastics exposure to have an impact on health, if a causal relationship exists, according to Ponnana. Nevertheless, based on the available evidence, it is reasonable to believe that microplastics may play some role in health and we must take steps to reduce exposures, he said. While it is not feasible to completely avoid ingesting or inhaling microplastics when they are present in the environment, given how ubiquitous and tiny they are, researchers said the best way to minimise microplastics exposure is to curtail the amount of plastic produced and used, and to ensure proper disposal.

“The environment plays a very important role in our health, especially cardiovascular health,” Ponnana said. “As a result, taking care of our environment means taking care of ourselves.”

In a separate study presented at ACC.25, researchers from a different group reviewed the scientific literature and found that studies showed a strong correlation between microplastics in plaques in the heart’s arteries and the risk of adverse cardiovascular events, suggesting that the presence of microplastics could play a role in the onset or exacerbation of serious heart problems.

Source: American College of Cardiology

Categories : Environmental Effects Pain ManagementTags :

Nature Relieves Physical Pain Signals in the Brain

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This effect even occurs with virtual nature – such as nature videos

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In a new study, an international team of neuroscientists led by the University of Vienna has shown that experiencing nature can alleviate acute physical pain. Surprisingly, simply watching nature videos was enough to relieve pain. Using functional magnetic resonance imaging, the researchers found that acute pain was rated as less intense and unpleasant when watching nature videos – along with a reduction in brain activity associated with pain. The results, published in Nature Communications, suggest that nature-based therapies can be used as promising complementary approaches to pain management.

“Pain processing is a complex phenomenon” explains study lead and doctoral student Max Steininger from the University of Vienna. In order to better understand it and identify treatment options, Steininger and his colleagues investigated how nature exposure influences pain: participants suffering from pain were shown three types of videos: a nature scene, an indoor scene, and an urban scene. The participants rated the pain while their brain activity was measured using functional magnetic resonance imaging. The results were clear: when viewing the nature scene, the participants not only reported less pain but also showed reduced activity in brain regions associated with pain processing.

By analyzing the brain data, the researchers showed that viewing nature reduced the raw sensory signal the brain receives when in pain. “Pain is like a puzzle, made up of different pieces that are processed differently in the brain. Some pieces of the puzzle relate to our emotional response to pain, such as how unpleasant we find it. Other pieces correspond to the physical signals underlying the painful experience, such as its location in the body and its intensity. Unlike placebos, which usually change our emotional response to pain, viewing nature changed how the brain processed early, raw sensory signals of pain. Thus, the effect appears to be less influenced by participants’ expectations, and more by changes in the underlying pain signals,” explains Steininger.

Claus Lamm, head of research in the group, adds: “From another ongoing study, we know that people consistently report feeling less pain when exposed to natural environments. However, the underlying reason for this has remained unclear – until now. Our study suggests that the brain reacts less to both the physical source and the intensity of the pain.”

The current study provides important information on how nature can help alleviate pain and highlights that nature-based therapeutic approaches can be a useful addition to pain treatment. The fact, that this effect was observed by simply watching nature videos suggests that taking a walk outdoors may not be necessary. Virtual nature – such as videos or virtual reality – appears to be effective as well. This opens up a wide range of possible applications in both the private and medical sectors, providing people with a simple and accessible way to relieve their pain.

The study was conducted at the University of Vienna in collaboration with researchers from the Universities of Exeter and Birmingham (UK) and the Max Planck Institute for Human Development.

Source: University of Vienna

Categories : Environmental EffectsTags :

Brewing Tea Removes Lead from Water

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Good news for tea lovers: That daily brew might be purifying the water, too. In a new study, Northwestern University researchers demonstrated that brewing tea naturally adsorbs heavy metals like lead and cadmium, effectively filtering dangerous contaminants out of drinks. Heavy metal ions stick to, or adsorb to, the surface of the tea leaves, where they stay trapped.

The study was published in the journal ACS Food Science & Technology.

“We’re not suggesting that everyone starts using tea leaves as a water filter,” said Northwestern’s Vinayak P. Dravid, the study’s senior author. “In fact, we often utilise model experiments and tweak diverse parameters to probe and understand the scientific principles and phenomena involved in capture/release cycles of contaminants. For this study, our goal was to measure tea’s ability to adsorb heavy metals. By quantifying this effect, our work highlights the unrecognised potential for tea consumption to passively contribute to reduced heavy metal exposure in populations worldwide.”

“I’m not sure that there’s anything uniquely remarkable about tea leaves as a material,” said Benjamin Shindel, the study’s first author. “They have a high active surface area, which is a useful property for an adsorbent material and what makes tea leaves good at releasing flavor chemicals rapidly into your water. But what is special is that tea happens to be the most consumed beverage in the world. You could crush up all kinds of materials to get a similar metal-remediating effect, but that wouldn’t necessarily be practical. With tea, people don’t need to do anything extra. Just put the leaves in your water and steep them, and they naturally remove metals.”

Exploring different variables

To conduct the study, the Northwestern team explored how different types of tea, tea bags and brewing methods affect heavy metal adsorption. The various varieties tested included “true” teas such as black, green, oolong and white, as well as chamomile and rooibos teas. They also examined the differences between loose-leaf and commercially bagged tea.

The researchers created water solutions with known amounts of lead and other metals (chromium, copper, zinc and cadmium), and then heated the solutions to just below boiling temperature. Next, they added the tea leaves, which steeped for various time intervals, from mere seconds to 24 hours.

After steeping, the team measured how much of the metal content remained in the water. By comparing metal levels before and after adding the tea leaves, they were able to calculate how much was effectively removed.

Cellulose bags work best — and don’t release microplastics

After multiple experiments, Dravid, Shindel and their team identified several trends. Perhaps somewhat unsurprising: The bag matters. After testing different types of bags without tea inside, the researchers found cotton and nylon bags only absorbed trivial amounts of the contaminants. The cellulose bags, however, worked incredibly well.

The key to a successful sorbent material is high surface area. Similar to how a magnet attaches to a refrigerator door, metal ions cling to the surface of a material. So, the more area for the particles to stick to, the better. Shindel posits that cellulose, which is a biodegradable natural material made from wood pulp, has higher surface area – and therefore more binding sites – than sleeker synthetic materials.

“The cotton and nylon bags remove practically no heavy metals from water,” Shindel said. “Nylon tea bags are already problematic because they release microplastics, but the majority of tea bags used today are made from natural materials, such as cellulose. These may release micro-particles of cellulose, but that’s just fiber which our body can handle.”

Longer steeping time, fewer metals

When comparing different varieties of tea, the researchers discovered tea type and grind played minor roles in adsorbing contaminants. Finely ground tea leaves, particularly black tea leaves, absorbed slightly more metal ions than whole leaves. Again, the researchers attributed this to surface area.

“When tea leaves are processed into black tea, they wrinkle and their pores open,” Shindel explained. “Those wrinkles and pores add more surface area. Grinding up the leaves also increases surface area, providing even more capacity for binding.”

Out of all the experiments, one factor stood out most. Steeping time played the most significant role in tea leaves’ ability to adsorb metal ions. The longer the steeping time, the more contaminants were adsorbed.

“Any tea that steeps for longer or has higher surface area will effectively remediate more heavy metals,” Shindel said. “Some people brew their tea for a matter of seconds, and they are not going to get a lot of remediation. But brewing tea for longer periods or even overnight – like iced tea – will recover most of the metal or maybe even close to all of the metal in the water.”

Future opportunities

Although results depend on several factors – steeping time and water-to-tea ratio, for example – tea preparation removes an amount of lead from water that should be significant from a public health perspective.

From their experiments, the researchers estimate that tea preparation can remediate about 15% of lead from drinking water, even up to lead concentrations as high as 10 parts per million. That estimate applies only to a “typical” cup of tea, which includes one mug of water and one bag of tea, brewed for three to five minutes. Changing the parameters remediates different levels of lead. Steeping for longer than five minutes, for example, adsorbs more lead compared to the average steeping time.

“Ten parts lead per million is obviously incredibly toxic,” Shindel said. “But with lower concentrations of lead, tea leaves should remove a similar fraction of the metal content in the water. The primary limiting factor is how long you brew your tea for.”

In high-resource areas of the world, it’s unlikely that concentrations will reach such high levels. And if there is a water crisis, brewing tea will not solve the problem. But Shindel said the study’s results provide useful new information that could be applied to public health research.

“Across a population, if people drink an extra cup of tea per day, maybe over time we’d see declines in illnesses that are closely correlated with exposure to heavy metals,” he said. “Or it could help explain why populations that drink more tea may have lower incidence rates of heart disease and stroke than populations that have lower tea consumption.”

Source: Northwestern University

Categories : Environmental Effects Neurology PaediatricsTags :

High Temperatures Could Impact the Brain Function of Young Children

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Exposure to high ambient temperatures is associated with lower connectivity in three brain networks in preadolescents, suggesting that heat may impact brain function. This is the conclusion of a study led by the Barcelona Institute for Global Health (ISGlobal). The results have been published in the Journal of the American Academy of Child & Adolescent Psychiatry. 

The study involved 2229 children aged 9 to 12 from the “Generation R” cohort in Rotterdam, Netherlands. Functional connectivity data from brain networks, i.e., how different regions of the brain communicate and collaborate, were assessed using resting-state magnetic resonance imaging, when the children were not performing any active tasks. Daily mean temperature estimates were obtained from the UrbClim urban climate model, developed by the Flemish Institute for Technological Research. Temperature values were calculated for the period from 2013 to 2015, assigning daily averages to each participant based on their home address.

Higher ambient temperatures during the week preceding the MRI assessment were associated with lower functional connectivity within the medial parietal, salience, and hippocampal networks, which are essential for proper brain functioning. This implies that brain areas may work less synchronously, affecting processes such as attention, memory, and decision-making. The medial parietal network is related to introspection and self-perception; the salience network detects environmental stimuli and prioritises what deserves our attention; and the hippocampal network is critical for memory and learning.

The research shows that the association between high temperatures and lower functional connectivity was strongest on the day before the brain scan and progressively decreased on subsequent days. In contrast, low average daily temperatures were not associated with functional connectivity.

“We hypothesise that dehydration could explain our findings, as children are particularly vulnerable to fluid loss when exposed to heat, which can affect the functional connectivity of brain networks,” says study lead author Laura Granés, researcher at IDIBELL and ISGlobal.

“In the current climate emergency, public health policies aimed at protecting children and adolescents from high temperatures could help mitigate potential effects on brain function,” says Mònica Guxens, ICREA researcher at ISGlobal and senior author of the study.

Implications for mental health

Although brain function alterations have been suggested as a possible mechanism linking temperature and mental health, no study to date has examined the effects of ambient temperature on functional brain networks. In another recent study, the same research team found that exposure to cold and heat can affect psychiatric symptoms such as anxiety, depression and attention problems. In addition, other studies have linked lower connectivity within the brain’s salience network to suicidal ideation and self-harming behaviours in adolescents with depression, as well as to anxiety disorders.

“Given the role of the salience network in suicidal ideation, our findings raise a new hypothesis: high temperatures could decrease the functional connectivity of this network, indirectly contributing to a higher risk of suicide in individuals with pre-existing mental health conditions,” explains Carles Soriano-Mas, researcher at IDIBELL and the University of Barcelona and one of the study’s authors. “While we do not propose that these connectivity changes, triggered by heat exposure, directly induce suicidal behaviours, they could act as a trigger in vulnerable individuals,” adds the researcher. 

Source: Barcelona Institute for Global Health (ISGlobal)