natural sources

Decontaminating Drinking Water | Earth Wise

July 24, 2023 By EarthWise Leave a Comment

At least two billion people around the world often drink water that is contaminated with disease-causing microbes. Waterborne diseases are responsible for two million deaths each year, mostly among children under the age of five.

There are various ways to decontaminate water, including chemicals that can themselves produce toxic byproducts as well as using ultraviolet light, which takes fairly long to disinfect the water and requires a source of electricity.

Scientists at Stanford University and the SLAC National Accelerator Laboratory have recently invented a low-cost, recyclable powder that kills thousands of waterborne bacteria every second when the water containing it is exposed to ordinary sunlight. The discovery of this ultrafast disinfectant could be a tremendous benefit to the nearly 30% of the world’s population with no reliable access to safe drinking water.

The new disinfectant is a harmless metallic powder that works by absorbing both ultraviolet and high-energy visible light from the sun. It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide. The key innovation is that when these four metallic ingredients are immersed in water, they all function together by reacting with the surrounding water and generating chemicals that quickly kill bacteria. The chemicals themselves don’t last long. They quickly break down in the water leaving completely safe drinking water.

The nontoxic powder is recyclable. It can be removed from water with a magnet. It can also be reused at least 30 times. Apart from its uses in less developed parts of the world, it could be valuable for hikers and backpackers who want to drink water from natural sources of unknown quality.

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New nontoxic powder uses sunlight to quickly disinfect contaminated drinking water

Photo, posted February 27, 2013, courtesy of Petras Gagilas via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Nitrous Oxide Is No Laughing Matter | Earth Wise

November 10, 2020 By EarthWise Leave a Comment

Carbon dioxide is the most well-known of greenhouse gases. But there are others deserving of their own spotlight. Nitrous oxide is one of them. It turns out that the same “laughing gas” once used by dentists as an anesthetic is pretty bad for the environment. In fact, it’s more than 300 times more potent as a greenhouse gas than carbon dioxide, and it can remain in the atmosphere for more than 100 years.

According to a new study by a team of international scientists, rising nitrous oxide emissions around the world are jeopardizing the climate goals of the Paris Agreement. The growing use of nitrogen fertilizers in global food production is increasing atmospheric concentrations of nitrous oxide.

The study, which was led by Auburn University and recently published in the journal Nature, finds that nitrous oxide emissions are increasing faster than any emission scenario developed by the Intergovernmental Panel on Climate Change. The current trajectory would lead to global mean temperature increases well above 3°C from pre-industrial levels. The Paris Agreement aims to limit global warming to less than 2°C.

According to the study, nitrous oxide levels have risen 20% from pre-industrial levels, with the fastest growth observed in the last 50 years due to emissions from human activities. The largest contributors to nitrous oxide emissions come from East Asia, South Asia, South America, and Africa. The United States, China, and India dominate nitrous oxide emissions from synthetic fertilizers, while Africa and South America dominate releases of nitrous oxide from natural sources, like livestock manure.

Nitrous oxide emissions pose an increasing threat to the climate.

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Nitrous oxide emissions pose an increasing climate threat, study finds

Photo, posted April 22, 2012, courtesy of Bill Meier via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Humans And Vertebrate Mortality

April 9, 2019 By EarthWise Leave a Comment

According to a new study, more than one-quarter of the planet’s land vertebrates die because of humans. This is a “disproportionately huge effect” on the other land vertebrates that share planet’s surface with us.

Researchers from the SUNY College of Environmental Science and Forestry and the U.S. Department of Agriculture reviewed 1,114 published studies in which nearly 43,000 animals had perished. Their study, which was recently published in the journal Global Ecology and Biogeography, found that 28% of the animals’ deaths were directly attributable to humans. The other 72% died from natural sources.

Mammals, birds, reptiles, and amphibians that died between 1970 and 2018 in the Americas, Asia, Africa, Europe, and Oceania were the foundation of the study. All of these vertebrates had been either collared or tagged as part of other research projects.

The researchers point out that humans are only one among more than 35,000 species of terrestrial vertebrates globally. The fact that humans are responsible for more than one-quarter of their deaths illustrates the profound magnitude of the problem. And that statistic is just the direct causes. According to the researchers, when urban growth and other land use changes that erode habitat are considered, the human impact is likely even greater.

The study found that the impact of humans across all the different species was not equal. In fact, larger animals were more likely to be killed by humans than smaller animals. Adult animals were more likely to be killed by humans than juveniles.

The researchers conclude that humans are such a major contributor to terrestrial vertebrate mortality that they could potentially impact both evolutionary processes and ecosystem functioning.

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On the land, one-quarter of vertebrates die because of humans

Photo, posted March 6, 2019, courtesy of USFWS Midwest Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.