contaminants

Bees and urban wildflowers

May 23, 2025 By EarthWise Leave a Comment

Post-industrial cities often have large numbers of vacant lots, left behind as people have moved out of the area. Local residents are often tempted to plant wildflowers to make these deserted spaces more attractive.

Wildflowers are an important food source for bees. Pollinators like bees play a vital role in food production and attracting them with food sources is a good idea. However, a study by researchers at the University of Cambridge in the UK found that there are dangers associated with planting wildflowers in some urban settings.

Wildflowers growing on land previously used for buildings and factories can accumulate lead, arsenic, and other metal contaminants from the soil. These metals have previously been shown to damage the health of pollinators that ingest the metals in the nectar as they feed.

The Cambridge study was carried out in Cleveland, Ohio, which has nearly 34,000 vacant lots. Cleveland was previously the site of iron and steel production, oil refining, and car manufacturing. The researchers tested the nectar from flowering plants growing on disused land throughout the city. Lead was the contaminant found in the highest concentrations. They also found that different species of plants accumulate different amounts and different types of metals.

The goal of the study was not to discourage the planting of wildflowers in towns and cities. It is to highlight the importance of growing the right species of wildflowers as well as to encourage testing soils for metals before planting wildflowers and to clean up pollution. Wildflowers are important for pollinators, but it is also important that they don’t contribute to the decline of pollinator populations that has already been happening for a number of reasons.

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Growing wildflowers on disused urban land can damage bee health

Photo, posted August 26, 2012, courtesy of RJP via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Thawing permafrost in the Arctic

February 18, 2025 By EarthWise Leave a Comment

Permafrost covers about a quarter of the landmass in the Northern Hemisphere. It stores vast quantities of organic carbon in the form of dead plant matter. As long as it stays frozen, it is no threat to the climate. But as permafrost thaws, microorganisms start breaking down that plant matter and large amounts of carbon are released into the atmosphere in the form of carbon dioxide and methane.

Scientists estimate that there could be two and a half times as much carbon trapped in Arctic permafrost as there is in the atmosphere today.

Thawing permafrost poses various risks to the Arctic environment and the livelihoods of its people. According to a new study led by researchers from the University of Vienna in Austria, Umeå University in Sweden, and the Technical University of Denmark, thawing permafrost threatens the way of life of up to three million people.

To identify these risks, the research team studied four Arctic regions in Norway, Greenland, Canada, and Russia between 2017 and 2023. The research, which was recently published in the journal Communications Earth and Environment, identified five key hazards posed by the thawing permafrost: infrastructure failure, disruption of mobility and supply, decreased water quality, challenges for food security, and exposure to diseases and contaminants.

These are present developments – not future dangers. Global scientific cooperation, policy interventions, and investment in research are critical to mitigate the impact of thawing permafrost and address the broader consequences it brings.

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A transdisciplinary, comparative analysis reveals key risks from Arctic permafrost thaw

Thawing permafrost threatens up to three million people in Arctic regions

Photo, posted February 9, 2017, courtesy of Benjamin Jones / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fertilizers from wastewater sludge

July 30, 2024 By EarthWise Leave a Comment

Sewage sludge is the mud-like residue that is produced as a byproduct during wastewater treatment. In the U.S., sewage sludge is referred to as biosolids after it’s been treated. The term is meant to distinguish the higher quality, treated sludge from raw sludge and from sludge that contains large quantities of environmental pollutants.

However, according to a new study by researchers from Johns Hopkins University, fertilizers manufactured from the sludgy leftovers of wastewater treatment processes can still contain traces of potentially hazardous organic chemicals.

The research, which was recently published in the journal Environmental Science & Technology, provides one of the most comprehensive looks at the chemical composition of biosolids across the country.

Biosolids do contain valuable organic matter and nutrients, including nitrogen and phosphorus. According to the U.S. Environmental Protection Agency, more than half of the 3.76 million tons of biosolids produced in the U.S. in 2022 fertilized agricultural lands, golf courses, and other landscaped areas.

In the study, the research team screened 16 samples of biosolids from wastewater treatment facilities in nine U.S. and three Canadian cities. The researchers then created lists of the chemicals found in each sample. They found 92 common compounds that were present in 80% or more of the samples. The researchers cross-referenced those 92 compounds against the EPA’s CompTox Chemical Dashboard to identify which chemicals were most likely to pose threats to human health or the environment.

The findings could help the EPA identify which organic compounds to investigate further and which chemical contaminants may need government regulation.

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Team Aims to Improve Safety of Fertilizers Made from Wastewater Sludge

Photo, posted November 2, 2011, courtesy of Susana Secretariat via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Brownfields and solar power

December 19, 2023 By EarthWise Leave a Comment

Brownfields are blighted lands that have suffered environmental contamination, making it very difficult to redevelop them or make good use of them. Generally, they are previously used lands that have the presence or at least the potential presence of hazardous substances, pollutants, or other contaminants at levels exceeding health-based or environmental standards. There are nearly half a million brownfields in the U.S. that are ripe for repurposing.

One very attractive use for brownfields is to convert them to “brightfields,” which is the colloquial term for brownfields redeveloped into solar projects. Estimates are that nearly 200,000 U.S. brownfield sites are eligible for brightfield conversion, which could provide hundreds of gigawatts of energy production. Over 10,000 of these sites are inactive landfills, which alone could power 8 million homes. Many of these sites have sat unused for decades.

A recent success story took place in Old Bridge Township, New Jersey where an abandoned waste site – designated a Superfund site by the EPA for decades – has now become a solar project that will generate more than $1.2 million a year for the township and will provide reduced-cost electricity for 400 homes, half of which are low- and moderate-income residents.

The site was on the EPA list of Superfund National Priorities , meaning it was considered one of the most serious abandoned hazardous waste sites. Such sites required continuous monitoring, modifications, and cleanup.

Projects like the Old Bridge solar project are likely to become increasingly common in the future, as legacy liabilities can be turned into valuable assets.

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How solar installations give new life to blighted brownfields

Photo, posted November 11, 2015, courtesy of Martin Malec via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Superstrong Nanofibers | Earth Wise

March 5, 2021 By EarthWise Leave a Comment

Self-assembly is a ubiquitous process in the natural world that leads to the formation of the DNA double helix, the creation of cell membranes, and to many other structures. Scientists and engineers have been working to design new molecules that assemble themselves in water for the purpose of making nanostructures for biomedical applications such as drug delivery or tissue engineering. For the most part, the materials created in this way have been chemically unstable and tended to degrade rapidly, especially when the water is removed.

A team at MIT recently published a paper describing a new class of small molecules they have designed that spontaneously assemble into nanoribbons with unprecedented strength and that retain their structure outside of water.

The material is modeled after a cell membrane. Its outer part is hydrophilic (it likes to be in water) and its inner part is hydrophobic (it tries to avoid water.) This configuration drives the self-assembly to create a specific nanostructure and by choosing the appropriate chemicals to form the structures, the result was nanoribbons in the form of long threads that could be dried and handled. The resultant material in many ways resembles Kevlar. In particular, the threads could hold 200 times their own weight and have extraordinarily high surface areas. The fibers are stronger than steel and the high surface-to-mass ratio offers promise for miniaturizing technologies for such applications as pulling heavy-metal contaminants out of water and for use in electronic devices and batteries.

The goal of the research is to tune the internal state of matter to create exceptionally strong molecular nanostructures. The potential for important new applications is considerable and exciting.

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Researchers construct molecular nanofibers that are stronger than steel

Photo, posted June 19, 2007, courtesy of Andrew Hitchcock via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Artificial Aquatic Polyps | Earth Wise

September 16, 2020 By EarthWise Leave a Comment

Corals are often mistaken for rocks because of their hardened surfaces. And, since they attach or “take root” to the sea floor, they are often mistaken for plants. But unlike rocks, corals are alive. And unlike plants, corals do not make their own food. Corals are actually animals.

Most of these structures that we call “coral” are made up of hundreds to thousands of tiny coral creatures called polyps. A coral polyp, which is often no thicker than a nickel, has a saclike body and mouth that is encircled by stinging tentacles. Polyps are responsible for a host of ecosystem services, including nourishing corals, and aiding coral survival by generating self-made currents through the motion of their soft bodies.

Inspired by these marine organisms, researchers from the University of Warwick in the UK and Eindhoven University of Technology in the Netherlands have collaborated to develop an artificial aquatic polyp capable of removing contaminants from water. The 1 square centimeter wireless robot polyp can attract, grasp, and release objects, moving under the influence of a magnetic field and whose “tentacles” are triggered by light.

The next step for the researchers is to see if the technology can be successfully scaled up from laboratory to pilot scale. In order for that to happen, the team has to design an array of artificial polyps capable of working harmoniously together.

Corals are an incredibly important part of ocean ecosystems. And while it remains to be seen how much value artificial polyps can achieve in future applications, it serves as another example of scientists emulating nature to create more sustainable designs.

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