Perfectionism, misinformation, and safety during the pandemic

Sustainable strategies to treat urban runoff

As urban areas increase, so does urban runoff, directly impacting surface water quality and storage. We know the lakes and rivers in and around urban environments contain plastic debris, detergents, pesticides, heavy metals, and other contaminants. This can cause acute toxicity to aquatic organisms, or even present a chronic risk to ecosystems and to humans via seafood and drinking water. For example, urban runoff mortality syndrome is a phenomenon that describes mass die-offs in salmon in the Pacific Northwest due to untreated stormwater.

New research is showing that urban runoff toxicity is ill-defined and potentially underestimated globally. Researchers including Mathieu Lapointe, postdoctoral researcher at McGill University, and Nathalie Tufenkji, Professor of Chemical Engineering at McGill University and Canada Research Chair in Biocolloids and Surfaces, are calling for cities to better manage and treat urban runoff to protect sources of drinking water and reduce the impacts on aquatic ecosystems.

The researchers argue that international actions and policies should be implemented to control pollutant release and prevent adverse ecological impacts. “Densely populated cities need sustainable solutions such as retention ponds and settling tanks to simultaneously treat and store runoff,” said Lapointe and Tufenkji. “Such retention processes could act as on-site surge tanks while also removing several contaminants from runoff before discharge into natural waters.”

“Sustainable strategies to treat urban runoff needed” by Nathalie Tufenkji, Mathieu Lapointe, and Chelsea M. Rochman was published in Nature Sustainability.

Invasive insects will kill 1.4 million US street trees by 2050: study

A new study by researchers from McGill University, the USDA Forest Service Southern Research Station and North Carolina State University estimates that over the next 30 years, 1.4 million street trees will be killed by invasive insects, costing over $900 million USD to replace. The findings are published in the British Ecological Society’s Journal of Applied Ecology.

McGill PhD graduate Emma J. Hudgins , the study’s lead author, created the first nationwide spatial forecast of street tree mortality from invasive insects, building models to extrapolate to roughly 30,000 urban areas across the United States. Now a post-doctoral fellow at Carleton University, Hudgins puts forth that 90 per cent of the 1.4 million tree deaths forecasted in the study are predicted to be caused by the emerald ash borer (Agrilus planipennis), which is expected to kill virtually all ash trees in more than 6,000 urban areas. The researchers predict that the impact of invasive insects will not be evenly spread across the country, with less than a quarter of US communities set to experience 95 per cent of all street tree mortality resulting from invasive insects.

The team says that their findings can help urban tree managers to know which tree species, in which areas, will be at the greatest risk from invasive insects. Their findings can be used to prioritize management efforts such as quarantining wood products. “These results can hopefully provide a cautionary tale against planting a single species of tree throughout entire cities, as has been done with ash trees in North America. Increasing urban tree diversity provides resilience against pest infestations,” Hudgins said.

“Hotspots of pest-induced US urban tree death, 2020–2050” by Emma J. Hudgins et al. was published in the Journal of Applied Ecology.

Lower-income populations will be hardest hit by heat waves

The poorest parts of the world are likely to be two to five times more exposed to heat waves than richer countries by the 2060s, according to a new study led by Professor Jan Adamowski and Mohammad Reza Alizadeh from the Department of Bioresource Engineering. By the end of the century, the heat exposure of the poorest quarter of the global population will match that of the entire rest of the world.

To assess how heat wave exposure is changing, the researchers analyzed heat waves around the world over the past 40 years and then used climate models to project ahead. They also incorporated estimates of countries’ ability to adapt to rising temperatures and lower their heat exposure risk. The researchers found that while wealthy countries can buffer their risk by rapidly investing in measures to adapt to climate change, the poorest quarter of the world will face escalating heat risk. Compared to the wealthiest quarter of the world, the poorest quarter lags in adapting to rising temperatures by about 15 years on average. The results provide more evidence that investing in adaptation worldwide will be crucial to avoid climate-driven human disasters, the researchers say.

“Increasing Heat-Stress Inequality in a Warming Climate” by Mohammad Reza Alizadeh et al. was published in Earth’s Future.

Global environmental risks and treated wastewater

Surprisingly, wastewater, even when treated, can represent sources of concentrated pollution, including from household pharmaceuticals. To investigate the impact of wastewater effluents on the water quality of receiving waterbodies, scientists need to know where and how much wastewater is being released from treatment plants. McGill University scientists have compiled a new global database showing the locations and characteristics of 58,502 wastewater treatment plants around the world. Using this new information, Heloisa Ehalt Macedo, a PhD student in the Department of Geography at McGill, and the research team identified 1.2 million km of rivers that receive treated wastewater discharge from these plants. This may pose a contamination risk if the wastewater is not treated adequately as some of the rivers that were investigated exceed a common threshold for environmental concern linked to wastewater dilution. This research is a first step towards identifying hotspots that are at greatest risk for water pollution from emerging contaminants such as household pharmaceuticals. It is also a step along the way to pinpointing individual treatment plants where improvements in treatment capability is critical to mitigate environmental risks.

“Distribution and characteristics of wastewater treatment plants within the global river network” by Ehalt Macedo et al was published in Earth System Science Data.

Higher levels of air pollution in snowbound cities

Snowbound cities such as Montreal have higher concentrations of black carbon, a powerful air pollutant, than cities in warmer climates according to researchers Houjie Li and Professor Parisa Ariya of the Department of Atmospheric and Oceanic Sciences and the Department of Chemistry. This is because particles of black carbon produced by diesel and other fossil fuels are transferred to surfaces through snow and then re-emitted to the atmosphere. Consequently, the same carbon emission rates in a warmer city can produce a much higher concentration of pollutants in a colder city. In comparing two pollution hotspots in Montreal, the researchers also found that concentrations of black carbon were 400% higher at the Montreal airport than in downtown Montreal. The study also points out that air quality norms around the world do not take into account the fact that cold climate conditions pose a particular threat to public health. Interestingly, the research also shows that during the COVID-19 lockdown period which started in March 2020, concentrations of black carbon in downtown Montreal decreased up to 72%, revealing that human activities accounted for most air pollutants.

“Black Carbon Particles Physicochemical Real-Time Data Set in a Cold City: Trends of Fall-Winter BC Accumulation and COVID-19” by Houjie Li et al. was published in the Journal of Geophysical Research-Atmospheres.

Projecting climate change more accurately

Scientists have been making projections of future global warming using powerful supercomputers for decades. But how accurate are these predictions? Modern climate models consider complicated interactions between millions of variables. They do this by solving a system of equations that attempt to capture the effects of the atmosphere, ocean, ice, land surface and the sun on the Earth’s climate. While the projections all agree that the Earth is approaching key thresholds for dangerous warming, the details of when and how this will happen differ greatly depending on the model used. Now, researchers from McGill University, including Professor Shaun Lovejoy and Roman Procyk of the Department of Physics hope to change all that. Building on an approach pioneered by Nobel prize winner Klaus Hasselmann, they have developed a new way to measure climate change more accurately and precisely. Their new projections are based on equations that combine the planet's energy balance and slow and fast atmospheric processes called “scaling”. This breakthrough opens new avenues of research on future and past climates on Earth, including ice ages. The new model can even be used to make precise regional temperature projections. By comparing their projections to the conventional ones used by Intergovernmental Panel on Climate Change, the researchers found that the new model gives overall support to the IPCC projections but with some significant differences. While the new model projects a crossing of the key thresholds for dangerous warming a bit later, the time frame for crossing it is much narrower. According to the researchers, there is a 50% chance of exceeding the 1.5C threshold by 2040.

“The Fractional Energy Balance Equation for Climate projections through 2100” by Roman Procyk et al. was published in Earth System Dynamics.

Herbicide Roundup disturbing freshwater biodiversity

As Health Canada extends the deadline on public consultation on higher herbicide concentrations in certain foods, research from McGill University shows that the herbicide Roundup, at concentrations commonly measured in agricultural runoff, can have dramatic effects on natural bacterial communities. "Bacteria are the foundation of the food chain in freshwater ecosystems. How the effects of Roundup cascade through freshwater ecosystems to affect their health in the long-term deserves much more study,” say the researchers.

"Resistance, resilience, and functional redundancy of freshwater bacterioplankton communities facing a gradient of agricultural stressors in a mesocosm experiment" was published in Molecular Ecology.

Mapping the genome of lake trout to ensure its survival

An international team of researchers from the U.S. and Canada, including researchers from McGill University, have managed to create a reference genome for lake trout to support U.S. state and federal agencies with reintroduction and conservation efforts. Lake trout, once the top predator fish across the Great Lakes, reached near extinction between the 1940s and 1960s due to pollution, overfishing, and predation by the invasive lamprey eel. Once showing striking levels of diversity in terms of size, appearance, and ability to adapt to varied environments, now the only lake trout populations to have survived are to be found in Lake Superior and Lake Huron. Genomes of salmonids, a family that includes lake trout, are harder to compile than those of many other animals, the research team said. “Between 80-100 million years ago, the ancestor of all salmonid species that lake trout belong to went through a whole genome duplication event. As a result, salmonid genomes are difficult to assemble due to their highly repetitive nature and an abundance of duplicated genomic regions with similar sequences,” explains Ioannis Ragoussis, the Head of Genome Sciences at the McGill Genome Centre, where the sequencing took place.

"A chromosome-anchored genome assembly for Lake Trout (Salvelinus namaycush)" was published in Molecular Ecology Resources.

Why do species live where they do?

As the climate changes, what factors will decide where species can survive and thrive? Scientists try to answer this question by studying what governs where species live today. Harsh and cold environmental conditions play a role, especially toward the poles like in Canada. But researchers Anna Hargreaves, an Assistant Professor in the Department of Biology and Alexandra Paquette show that interactions with other species – like competition and predation – are also major driving factors in determining where species can live, especially in warmer conditions toward the equator.

"Biotic interactions are more often important at species’ warm versus cool range edges" was published in Ecology Letters.