Micro-nano plastics make other pollutants more dangerous to plants and intestinal cells

Rutgers University

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Micro- and nanoscale plastic particles in soil and water can significantly increase how much toxic chemicals plants and human intestinal cells absorb, according to two new studies from Rutgers Health that raise fresh concerns about food safety from plastic pollution.

The first study in NanoImpact found that lettuce exposed to both nanoscale plastic particles and common environmental pollutants such as arsenic took up substantially more of the toxic substances than plants exposed to the pollutants, alone confirming the risks of polycontamination of our food chain. A companion study in Microplastics journal showed similar effects in human intestinal tissue.

The combination of both studies suggests micro and nano plastics, the byproduct of fragmentation of plastics in the environment over time, could be creating a dangerous cycle of contamination: making plants absorb more toxic chemicals that we might then eat, while making our bodies more likely to also absorb both those toxins and the plastics themselves and increasing risks for diseases, especially for susceptible populations. 

"We’ve already put about 7 billion metric tons of plastics into the environment that keep breaking apart," said Philip Demokritou, director of the Nanoscience and Advanced Materials Center at Environmental Occupational HealthSciences Institute at Rutgers University and senior author of both studies. "They pollute everything around us – the water we drink, the food we eat, the air we breathe."

Using a cellular model of the human small intestine, coupled with a lab-based gastrointestinal apparatus that simulates the digestive system, the researchers found that nano-size plastic particles increased the absorption of arsenic by nearly six-fold compared with arsenic exposure alone. The same effect was seen with boscalid, a commonly used pesticide, said the researchers from Rutgers, the Connecticut Agriculture Experiment Station (CAES) and New Jersey Institute of Technology (NJIT).

The relationship, moreover, worked both ways: The presence of these environmental pollutants also significantly increased the amount of plastic absorbed by the intestinal tissue, with plastic uptake roughly doubling when toxins were present.

"We know nanoscale materials can bypass biological barriers," said Demokritou, the Henry Rutgers Chair and professor in nanoscience and environmental bioengineering at the Rutgers School of Public Health and the Rutgers School of Engineering. "The smaller the particles, the more they can bypass biological barriers in our bodies that protect us."

For the other paper, the researchers exposed lettuce plants to two sizes of polystyrene particles – 20 nanometers and 1,000 nanometers – along with arsenic and boscalid. They found the smaller particles had the biggest impact, increasing arsenic uptake into edible plant tissues nearly threefold compared to plants exposed to arsenic alone.

The effects occurred in both hydroponic systems and more realistic soil conditions. Using advanced imaging and analytical techniques, the researchers showed the plastic particles themselves were also accumulating in plant tissues, with the smaller particles more likely to move from roots into shoots.

Micro and nanoplastics come from the slow breakdown of larger pieces of plastic in the environment.

"Even if we stop today producing plastics or using plastics, we have plenty of plastic waste unfortunately out there," Demokritou said.

The research was part of a larger USDA-funded project examining food safety issues related to micro and nanoplastics. The scientists said more research is needed to understand the long-term implications and to develop potential solutions.

"We need to stick with the ‘three-R’ waste hierarchy – reduce the use of plastics, reuse, recycle," Demokritou said. "For areas where you cannot apply these three Rs, like in agriculture where so much plastic is used for weed control and other things, use biodegradable plastics."

The researchers are developing new biodegradable materials that could replace conventional plastics and methods to better detect and measure plastic particles in food and water. However, they said preventing further contamination needs to be a priority.

"It's not that technically we cannot address some of these issues," Demokritou said. "But it will definitely be a challenge to retain all the benefits from this very useful material while reducing the harms that it does. There are social and economic obstacles related to plastic production and use to overcome.”

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Journal

NanoImpact

DOI

10.1016/j.impact.2025.100541 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Micro-nanoscale polystyrene co-exposure impacts the uptake and translocation of arsenic and boscalid by lettuce (Lactuca sativa)

 

Older people in England are happier now than before the COVID pandemic, new national study suggests

Depression rates buck the trend and remain slightly higher than pre-COVID, reinforcing the need for policies addressing immediate and lingering effects of the pandemic on mental health

Taylor & Francis Group

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Older people have greater general happiness, life satisfaction and sense of purpose than they did before the Covid-19 pandemic.

That’s according to a new study which tracked 3,999 over 50s in England for 11 years, published today in the peer-reviewed journal, Aging and Mental Health.

Analysing data to understand positive psychological well-being and depression within this group, an expert team from UCL (University College London), funded by the National Institute of Ageing, a consortium of UK government departments coordinated by the National Institute for Health Research, and the UKRI Economic and Social Research Council, drew on data from the English Longitudinal Study of Ageing (ELSA) between 2012 to 2023.

They found that all aspects of psychological well-being declined in the second half of 2020, with happiness dropping by 4%, positive well-being by 4%, and life satisfaction by 7%. However, by 2021–2023, eudemonic well-being (whether a life feels worthwhile) had rebounded significantly, and both eudemonic well-being and life satisfaction had risen to levels even higher than before the pandemic.

The three types of positive well-being they analysed were: affective well-being (happiness), eudemonic well-being, and evaluative well-being (life satisfaction).

The picture with depression is a little more complex, however. Overall, rates of depression in older people rose from 11.4% before Covid to 27.2% during the pandemic. Afterwards, they remained slightly elevated at 14.9%. The authors hypothesize that this ongoing raised level might result from the pressure faced by the health service, with people unable to, or choosing not to, seek help.

Lead author Paola Zaninotto is a Professor of Medical and Social Statistics at UCL’s Department of Epidemiology and Public Health. With over two decades of experience conducting research in public health, she specializes in medical and social statistics and carries out a role as Deputy Director of the ELSA.

Commenting on the team’s findings, Professor Zaninotto says: “Our research showed that the pandemic had a profound effect on the well-being of older people in England.

“As many would expect, we found that well-being declined during the pandemic, and instances of depression rose. While depression is still slightly more prevalent than before 2020, remarkably, overall older people are now happier, more satisfied and have a greater sense of purpose than before the pandemic.

“We can only speculate on the reasons for this. It perhaps could reflect a renewed appreciation for social connections and meaningful activities, as well as increased psychological resilience after a period of adversity. Improved health security following widespread vaccinations could also have contributed to this positive shift.

“We saw marked differences by age and affluence, underscoring the importance of tailored support policies for the immediate and lingering effects of pandemics on the well-being of our older population.”

People in their 50s

Before the pandemic began, people in their 50s reported poorer positive well-being than older groups. This finding is supported by previous research which has shown that people in their late 60s and early 70s are happier than those in their 50s.  This finding may reflect unique challenges faced by people in their 50s, including midlife stressors such as financial responsibilities, caregiving roles, and work pressures.

During the pandemic, the researchers found that people in their 50s did not become significantly more unhappy, and suggest this may be because their positive well-being levels were already low. Increases in depressive symptoms were larger in this group, although they also showed greater recovery after the pandemic, suggesting a good degree of resilience or an ability to adapt.

People over 75

In people aged over 75, the team observed smaller improvements in depression and positive well-being than others after the pandemic. This could stem from persistent vulnerabilities as they may have socialized less, had more health limitations, or have been slower to adapt, psychologically. It could also be that their mental well-being was impacted by the long-lasting nature of the pandemic and the fact Covid was risker for them.

Affluent people

At all times, levels of depression were higher in the least affluent group. But perhaps counter-intuitively, the psychological well-being of wealthier participants fell more than that of the poorer cohort during the pandemic itself; they showed larger decreases in happiness, eudemonic well-being and life satisfaction. The authors suggest that it’s possible that they experienced relatively greater disruption to their lives, as they could not continue their perhaps more habitual traveling, socialising or dining out.

Depression and recommendations

The overall reduction in the prevalence of depression after the pandemic ended was only partial, suggesting, the authors state, “a need for continued mental health support, particularly for those who were most affected”.

“Our results reinforce the need for policies that address both the immediate and lingering effects of the pandemic on mental health,” adds Professor Zaninotto.

“Furthermore the findings demonstrate the importance of tailored support policies to address these impacts on mental health of our older population at large, over and above the serious effects of long Covid.”

Limitations

Strengths of this study include its large, representative sample and a methodology which offered a more consistent trajectory of tracking well-being changes to reaffirm the interplay between positive psychological well-being, age, and socioeconomic status.

Furthermore, the study included both in-person, internet and telephone interviews.

However, limitations of the study include the measurement of positive psychological well-being. “Constraints on assessment protocols during the pandemic prevented the use of multi-item measures,” explain the authors, who instead used a measure that “may not capture the full complexity and nuance of positive psychology”.

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Journal

Aging & Mental Health

DOI

10.1080/13607863.2025.2450260 

Method of Research

Survey

Subject of Research

People

Article Title

Recovery of psychological wellbeing following the COVID-19 pandemic: a longitudinal analysis of the English longitudinal study of ageing

Article Publication Date

11-Feb-2025

 POLLINATORS

Female hoverflies beat males on long-distance migrations

University of Exeter

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A female marmalade hoverfly

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Credit: Will Hawkes

Male hoverflies are outflown by females when it comes to long-distance migration, new research shows.

Marmalade hoverflies leave northern Europe each autumn to escape the cold winter.

The study – by the University of Exeter – compared the number of males and females migrating at a northern point (Denmark) and further south (Spain).

At the northern point, 50% of hoverflies were male and 50% were female – but at the southern point about 90% were female, suggesting males are “poor long-distance fliers”.

“We carried out a range of tests and found females were better adapted for long-distance migration,” said Toby Doyle, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“The reasons for this are unclear, but it’s possible that males prioritise fighting and mating, leaving little energy left for migration.”

The study did not track individual insects from one sample point to the other, but the sex differences at the two points show that females are far more likely to reach southern Europe.

The researchers designed experiments to work out why females are better long-distance flyers.

Female hoverflies performed better in flight tests, flying nearly nine times further than males. They also had lower wing “loading values” (less weight to carry in relation to wing size) and tolerated cold better, which is important for high-altitude flight.

Genetic tests showed females activated genes involved in immunity, resistance to low-oxygen environments and to increase lifespan. They also suppressed hormones to allow themselves to pause reproduction and redirect that energy towards migration.

“What surprised us most was the diverse range of traits seen in females that allow them to outperform the males,” said Dr Karl Wotton.

Doyle added: “These traits all seem to contribute to the success of female migrants, and this influences the make-up of the population across huge geographic areas and through the whole migratory and overwintering period.”

The lack of males making the southerly migration is probably not a risk to future hoverfly populations, as females can mate and store sperm prior to migration and use this to establish new populations in the spring.

The study was funded by the Royal Society.

The paper, published in the journal Open Biology, is entitled: “Multiple factors contribute to female dominance in migratory bioflows.”

A male marmalade hoverfly

Credit

Will Hawkes

Journal

Open Biology

Article Title

Multiple factors contribute to female dominance in migratory bioflows

Article Publication Date

12-Feb-2025

Model of Antarctica’s water enhances sea level forecasts

Study is the first to interpret subglacial hydrology for whole continent, improving analysis of Antarctic ice melt

University of Waterloo

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Researchers have generated the first dataset of water flow beneath the entire Antarctic Ice Sheet, which will lead to more accurate projections of sea level rise. 

The team from the University of Waterloo modeled Antarctica’s subglacial environment. The dataset represents the researchers’ best approximation of what the water flow underneath the ice sheet might currently look like. The results include numerous subglacial lakes developing below ice streams in both East and West Antarctica, and an extensive network of subglacial water channels that discharge large fluxes of water under many major glaciers. 

The model calculates how fast subglacial water is flowing and where it accumulates below the ice. It will significantly enhance the scientific community’s ability to accurately predict sea level rise from climate change. 

“Sea level rise will have negative consequences for us all,” said Dr. Shivani Ehrenfeucht, post-doctoral fellow in the Faculty of Environment.  “It is important for projections of sea level rise to be as accurate as possible so that policy makers and stakeholders can plan and adapt while we as a society strive to reach zero emissions as quickly as possible.”  

Before this continent-wide representation of the Antarctic subglacial environment, scientists had to estimate the water’s impact, but often this important factor would not be part of projections.  

“The water layer between the ice sheet and the bedrock is either entirely ignored in projections of sea level rise or modelers have to make an approximation as to what this layer should look like,” said Dr. Christine Dow, professor in the Faculty of Environment and Canada Research Chair in Glacial Hydrology and Ice Dynamics. “Now we’ve provided the dataset as a product so there’s no excuse any more for not including this really important aspect of ice behaviour.”  

Studies that include this water layer in their models of glacier flow end up predicting much higher degrees of glacier melt and mass loss by the end of the century.  

At nearly 14 million square kilometres, the Antarctic Ice Sheet covers nearly all of the continent and is nearly one and a half times the size of Canada. 

The study, Antarctic wide subglacial hydrology modeling, appears in Geophysical Research Letters. 

 

 

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Journal

Geophysical Research Letters

DOI

10.1029/2024GL111386 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Antarctic wide subglacial hydrology modeling

Why we need to expand the search for climate-friendly microalgae

As global efforts to combat climate change intensify, microalgae stand out as an underutilised yet promising resource.

University of Technology Sydney

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Variety of microalgal cultures being grown at UTS. Photo: Joan Labara Tirado.

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Credit: Joan Labara Tirado

New research has highlighted microalgae’s capacity as a solution in the fight against climate change, but researchers warn that “smart microalgal bioprospecting” is needed to unlock its full potential.  

The study highlights the vast, largely unexplored capacity of microalgae to mitigate CO2 emissions while driving sustainable industry. 

“Microalgae have remarkable properties that make them an ideal tool for tackling climate change,” said lead author, PhD candidate Joan Labara Tirado from the University of Technology Sydney (UTS). 

The review paper, The need for smart microalgal bioprospecting was recently published in the journal Natural Products and Bioprospecting. 

Beyond CO2 sequestration, microalgae offer significant promise as ‘cellular factories’ that can transform captured carbon into valuable products.  

“Microalgae grow incredibly fast, absorb CO2 at a much higher rate than terrestrial plants, and don’t compete for arable land, making them a viable option for sustainable carbon capture and industrial applications.” 

These include biofuels, pharmaceuticals, high-nutrient food sources, and even wastewater treatment, aligning with the principles of a circular economy. Successful examples include Spirulina which is widely used as a superfood or Dunaliella salina, a primary source of β-carotene for the cosmetics and food industries.  

Despite their promise, the industrial use of microalgae remains in its infancy. “Right now, we’re only scratching the surface,” said Labara Tirado. Only a small fraction of the thousands of microalgae species have been studied, leaving many untapped opportunities for climate innovation.  

“There are thousands of undiscovered microalgae species, each with potentially unique properties that could transform sectors like bioenergy, medicine or bioplastics.”   

Bioprospecting – the systematic search for valuable biological resources – plays a crucial role in identifying and developing new microalgal strains for industrial and environmental applications.  

This process involves discovering new species, analysing their biochemical properties, and assessing their potential to contribute to climate solutions. 

While microalgae are often hailed for their carbon capture potential, one of the major hurdles in scaling up microalgae-based carbon sequestration is cost. 

“These cost barriers have slowed widespread adoption, limiting the commercial viability of microalgae in carbon capture efforts,” said Labara Tirado. 

The discovery of new microalgae species with enhanced growth rates, higher CO2 absorption efficiency, or lower resource demands could dramatically reduce these costs. 

“By identifying and harnessing species that thrive in varied environmental conditions or require minimal inputs, researchers could pave the way for more economically viable carbon sequestration solutions,” said Labara Tirado. 

“But to get there, we need greater investment in smart microalgal bioprospecting – using advanced technology and research methods to find and develop new strains for industrial and environmental applications.” 

Labara Tirado isn’t just highlighting the challenges; his PhD is dedicated to pioneering new smart bioprospecting techniques aiming to accelerate the discovery of new microalgae species.  

However, targeted funding, innovation and research initiatives are crucial to scaling microalgae-based solutions.   

“The climate crisis demands unconventional solutions, and microalgae has the potential to play a major role in the transition to a greener future.”  

“We need to act now through research, policy support, and industry partnerships to fully harness their potential.” 

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Journal

Natural Products and Bioprospecting

DOI

10.1007/s13659-024-00487-3 

Method of Research

Systematic review

Subject of Research

Not applicable

Article Title

The need for smart microalgal bioprospecting