This article is  from The Conversation under a Creative Commons licence. All photos provided by  from various sources.

Rachel Buxton is an assistant professor in biology at �Ӱ�ԭ�� University.

More than  — approximately one in eight of us — are living with a mood, anxiety or substance use disorder. The prevalence of mental disorders is on the rise, 

The stresses of the city, , can  even further.

When most people think about caring for their mental health, they may think about getting more exercise, getting more sleep and making sure they’re eating healthy. Increasingly, research is showing that spending time in nature surrounded by plants and wildlife can also contribute to .

Our research focuses on the importance of birds and trees in urban neighbourhoods in promoting mental well-being. , we combined more than a decade of health and ecological data across 36 Canadian cities and found a positive association between greater bird and tree diversity and self-rated mental health.

The well-being benefits of healthy ecosystems will probably not come as a great surprise to urban dwellers who relish days out in the park or hiking in a nearby nature reserve. Still, the findings of our study speak to the potential of a nature-based urbanism that promotes the health of its citizens.

Birds, trees and human connection

Across cultures and societies, people have . The beauty of their bright song and colour have inspired art, music and poetry. Their contemporary cultural relevance has even earned them an affectionate, absurdist internet nickname: “.”

There’s something magical about catching a glimpse of a bird and hearing birdsong. For many urbanites, birds are our daily connection to wildlife and a gateway to nature. In fact, even if we don’t realize it, humans and birds are intertwined. Birds provide us with many  — controlling insects, dispersing seeds and pollinating our crops.

People have similarly intimate connections with trees. The terms tree of life, family trees, even tree-hugger all demonstrate the central cultural importance trees have in many communities around the world. In cities, trees are a staple of efforts to bring .

When the Australian city of Melbourne gave urban trees email addresses for people to report problems, residents responded by writing . Forest bathing, a .

Maclean’s magazine has released their  which once again highlight �Ӱ�ԭ�� University’s excellence.

�Ӱ�ԭ�� rose to No. 4 in Canada (No. 2 in Ontario) in the comprehensive category — universities with a significant amount of research activity and a wide range of programs at the undergraduate and graduate levels, including professional degrees.

“I am pleased that �Ӱ�ԭ��’s achievements continue to be recognized in these national rankings,” said �Ӱ�ԭ��’s Interim President and Vice-Chancellor, Jerry Tomberlin.

“The Maclean’s rankings highlight our strengths in research and the student experience which reflects our smart, caring community.”

�Ӱ�ԭ��’s leadership in research was again recognized as No. 1 in funding in the Social Sciences and Humanities.

Student support continues to be recognized as �Ӱ�ԭ�� secured top 5 rankings in the categories of Scholarships and Bursaries as well as Student Awards.

�Ӱ�ԭ�� is a home to top academic talent which is a testament to its ranking as No. 4 in Faculty Awards. In addition, �Ӱ�ԭ��’s Engineering program rose to No. 10 in the country.

This article is  from The Conversation under a Creative Commons licence. All photos provided by  from various sources.

Jesse Vermaire is an associate professor of environmental science at �Ӱ�ԭ�� University.  is a postdoctoral fellow of geography and environmental studies at �Ӱ�ԭ�� University.

Microplastic pollution is a global environmental problem that is ubiquitous in all environments, including ,  and .

Microplastics are readily found in treated wastewater sludge — also known as municipal biosolids — that eventually make their way to our agricultural soils.

 of microplastic levels in Canadian municipal biosolids found that a single gram of biosolids contains hundreds of microplastic particles. This is a much greater concentration of microplastics than is typically found in air, water or soil.

Given that hundreds of thousands of tonnes of biosolids are produced every year in Canada, we need to pay close attention to the potential impacts such high levels of microplastics might have on the environment and find ways to reduce microplastic levels in Canada’s wastewater stream.

Municipal biosolids

 are produced at wastewater treatment plants by settling and stabilizing the solid fraction of the municipal wastewater inflow.

In Canada and around the world, municipal biosolids are used to improve agricultural farmland soil. This is because they are rich in nutrients needed for plant growth, such as phosphorus and nitrogen.

Municipal biosolid applications are carefully  for heavy metals, nutrients and pathogens. However, guidelines for emerging contaminants, such as microplastics, are not currently available.

While current wastewater treatment plants are not explicitly designed to remove microplastics, they are nevertheless efficient at . The removed microplastics are often concentrated in the settled sludge and eventually end up in the biosolids.

Microplastics in municipal biosolids

Previous studies have shown that municipal biosolid waste is an important pathway for microplastics to enter the broader , including agricultural fields.

In collaboration with scientists from Environment and Climate Change Canada and Agriculture and Agri-Food Canada, we conducted the first pan-Canadian assessment of . We analyzed biosolid samples from 22 Canadian wastewater treatment plants across nine provinces and two biosolid-based fertilizer products.

We found hundreds of microplastic particles in every gram of biosolids. The most common type of microplastic particles we observed were microfibres, followed by small fragments. We found small amounts of glitter and foam pieces too.

Microplastic concentrations in municipal biosolids are substantially higher than other environmental networks in Canada like ,  and . This provides further evidence that microplastics are concentrated in biosolids produced at wastewater treatment plants.

Reducing microplastics

Wastewater treatment plants are well-equipped to remove large plastics like bottle caps and plastic bags from municipal wastewater. However, microplastic particles are so small they can’t be caught by current treatment infrastructure, so they end up concentrating in wastewater sludge.

As wastewater streams concentrate microplastics, they also offer an opportunity to reduce the plastic pollution that is entering the environment. While researchers across Canada are working to find insights on the short- and long-term ecological consequences of microplastic pollution on soil ecosystems, one solution is already clear.

Microplastics can be reduced at sources via systematic reductions in the use of single-use plastics, washing clothing with synthetic fibre less frequently and removing microfibres using . These approaches will help minimize the amount of microplastics that get into the wastewater stream and, ultimately, into the broader terrestrial and aquatic environments.

Building new technologies at our wastewater treatment plants to remove microplastics through physical or chemical means should also be explored.

We need to better understand the impact of high concentrations of microplastic on agro-ecosystems where biosolids are applied, including its impacts on . We also need to start building national guidelines for microplastic levels in biosolids and agricultural soils.

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Sunday, August 13, 2023 in 
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