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Humans And Microplastics | Earth Wise

April 13, 2022 By EarthWise Leave a Comment

While plastic comes in all different shapes and sizes, those that are less than five millimeters in length are called microplastics. Primary sources of microplastics include microfibers from clothing, microbeads, and plastic pellets (known as nurdles). Secondary sources of microplastics come from larger plastic debris, like bottles and bags, that degrades into smaller bits over time.

Microplastic pollution can be found everywhere on earth, from the top of the tallest mountains to the bottom of the deepest oceans. Microplastics are in the food we eat, the water we drink, and the air we breathe.

According to research recently published in the journal Exposure & Health, humans ingest an average of five grams of plastic particles per week. This is roughly equivalent to the weight of a credit card. The plastic particles are trafficked in via food, such as seafood and salt in particular, as well as water. In fact, those who rely on plastic bottled water for their drinking needs ingest an additional 1,700 plastic particles each week.

Microplastics have also been detected in human blood for the first time. According to new research recently published in the journal Environment International, scientists detected microplastics in nearly 80% of the people they tested.

Half of the blood samples contained PET plastic, which is commonly used for drinking bottles. One third of the blood samples contained polystyrene plastic, which is often used for food packaging. One quarter of the blood samples contained polyethylene plastic, which is used to make things like shopping bags and detergent bottles.

With plastic production predicted to double by 2040, more research is urgently needed to understand how ingesting microplastics affects human health.

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Web Links

Health risk due to micro- and nanoplastics in food

Microplastics found in human blood for first time

Discovery and quantification of plastic particle pollution in human blood

Photo, posted November 3, 2012, courtesy of Laura via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater As A Freshwater Source | Earth Wise

September 27, 2021 By EarthWise Leave a Comment

Water covers three-quarters of our planet, but freshwater – the water we drink, bathe in, and irrigate crops with – comprises only 3% of the world’s water and much of that is frozen in glaciers or otherwise unavailable. Nearly 3 billion people suffer from water scarcity for at least some of the year.

Natural freshwater sources – lakes, rivers, and groundwater – are under stress from the effects of climate change and from the increasing demands of city populations. The wastewater treatment plants in large cities represent a significant potential water source provided that sustainable and economical technologies to produce it can be developed.

Researchers at Lehigh University in Pennsylvania have patented an innovative ion exchange desalination process that is a legitimate candidate to transform wastewater into usable water.

Existing large-scale desalination systems make use of semipermeable reverse osmosis membranes that require an energy source to run the system. The Lehigh process, which they call HIX-Desal, harnesses the unique chemistry of carbon dioxide to take the place of the energy used in reverse osmosis systems.

Tests of the new system show that the salinity of treated wastewater can be reduced by more than 60% by the HIX-Desal process without requiring any reverse osmosis. At an Allentown, Pennsylvania water treatment plant where the system was tested, the researchers estimated that using the system could save about a million kWh per day in electricity usage, enough energy to power 94 homes for a year.

With this system, waste carbon dioxide from landfills or turbine exhaust can be used to desalinate municipal wastewater. It could be the basis of a circular economy.

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Desalination tech uses CO2 to tap into municipal wastewater as alternative freshwater source

Photo, posted November 28, 2020, courtesy of Richard Ricciardi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Residential Gardens And Pollinators | Earth Wise

April 2, 2021 By EarthWise Leave a Comment

A new study led by the University of Bristol in the UK measured for the first time how much nectar is produced in urban areas to gauge the role of residential gardens in providing nutrients for pollinators. They discovered that home gardens accounted for the vast majority of the crucial nutrients for pollinators; in fact, some 85% on average.

The study found that gardens generated a daily average of about a teaspoon of the unique sugar-rich liquid found in flowers which pollinators drink for energy. A teaspoon sounds like very little, but it is enough to feed thousands of bees.

The research examined nectar production in four major UK towns and cities and measured nectar production in nearly 200 species of plants. The results were that the nectar supply in urban landscapes is more diverse than in farmland and nature reserves. In addition, gardens are critical because they produce the most nectar per unit area of land and actually cover the largest area of land in the cities studied. In those cities, nearly a third of the land comprised domestic gardens, which is six times the area of parks and 40 times the area of small green allotments.

The upshot of the research is that home gardeners have a huge role to play in pollinator conservation. Without domestic gardens, there would be far less food for pollinators that include bees, wasps, butterflies, moths, flies, and beetles. Thus, it is important for home gardeners to keep planting nectar-rich flowers, mow lawns less often to let dandelions, clovers, and daisies flourish, avoid harmful pesticides, and avoid covering gardens in paving, decking, or artificial turf.

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Pioneering research reveals gardens are secret powerhouse for pollinators

Photo, posted June 23, 2018, courtesy of Wolfferl via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mollusks And Microplastics | Earth Wise

January 26, 2021 By EarthWise Leave a Comment

Plastic debris comes in all different shapes and sizes, but pieces that are less than five millimeters in length are called microplastics. Microplastics are everywhere, including in the food we eat, the water we drink, and the air we breathe.

Much of the oceanic microplastic pollution comes from the breakdown of plastic litter. Another source of microplastic pollution is microbeads. Microbeads, which are sometimes added to cleansing and exfoliating personal care products, pollute the environment when they get flushed down the drain.

According to a new study by researchers at Hull York Medical School and the University of Hull in the U.K., mussels, oysters and scallops have the highest levels of microplastic contamination among seafood. The research team examined 50 studies between 2014 and 2020 to determine the levels of microplastic contamination globally in fish and shellfish. The team found that microplastic content was 0-10.5 microplastics per gram in mollusks, 0.1-8.6 microplastics per gram in crustaceans, and 0-2.9 microplastics per gram in fish.

The researchers found that mollusks collected off the coasts of Asia were the most heavily contaminated with microplastics. China, Australia, Canada, Japan and the United States are among the largest consumers of mollusks, followed by Europe and the U.K.

While the human health implications of consuming microplastics are not well understood, early evidence from other studies suggest they do cause harm.

According to the research team, more data is needed from different parts of the world in order to better understand how microplastics vary between different oceans, seas, and waterways.

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Web Links

Highest levels of microplastics found in molluscs, new study says

Photo, posted September 3, 2007, courtesy of Andrew Malone via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Microplastics with Magnetism

October 7, 2019 By EarthWise 2 Comments

A new method for removing microplastics from the oceans has emerged from, of all things, a science fair project. An Irish 18-year-old named Fionn Ferreira developed his project for the annual Google Science Fair and it won the grand prize of $50,000 in educational funding.

The teenager was walking on the beach in his hometown and ran across a stone with oil and plastic stuck to it and became focused on the problem of microplastics increasingly entering the environment.

His idea was to make use of ferrofluids, which are nontoxic magnetic fluids made of oil and magnetite, which is an iron-based mineral. In the presence of water, the ferrofluids attract microplastics because both have similar properties.

Ferreira added oil and magnetite to water and mixed in a solution of microplastic particles. When the microplastics latched onto the ferrofluids, he dipped a magnet into the solution several times and the magnet removed both substances, leaving clear water. After almost 1000 tests, he demonstrated the method to be 88% effective in removing a variety of microplastics from water; a result even better than his original hypothesis of an 85% removal rate.

Ferreira is planning to further his education at a prestigious chemistry institute in the Netherlands starting in the fall.

According to a recent study, Americans eat, drink and breathe between 74,000 and 121,000 microplastic particles each year and, if they drink bottle water only instead of tap water, an additional 90,000 particles. So, a science fair project that might provide a way to get rid of most these things is definitely prize-worthy.

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This Irish teenager may have a solution for a plastic-free ocean

Photo, posted April 25, 2016, courtesy of Boe Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Bitter Truth About Caffeine

January 7, 2019 By EarthWise Leave a Comment

Black coffee has a bitter taste. Bitterness evolved as a natural warning system to protect the body from harmful substances. By the logic of evolution, we should therefore want to spit coffee out, but obviously it doesn’t work that way.

Caffeine itself has a particularly bitter taste. Surprisingly, a new study at Northwestern University has found that the more sensitive people are to the bitter taste of caffeine, the more coffee they drink. That sensitivity is actually a genetic variant.

So, one would think that people who are especially sensitive to the bitter taste of caffeine would drink less coffee. The counter intuitive result suggests that coffee consumers acquire a taste or an ability to detect caffeine as a result of the learned positive reinforcement (in other words, the buzz) elicited by caffeine. People with a heightened ability to taste coffee’s bitterness learn to associate good things with it.

The study also found in contrast that people sensitive to the bitter flavor of a different compound called 6-n-propylthiouracil (known as PROP)avoided coffee as well as red wine.

The study made use of applied Mendelian randomization, a technique commonly used in disease epidemiology, to test the causal relationship between bitter taste and beverage consumption in more than 400,000 men and women in the United Kingdom.

These results shed some light on the disdain many coffee drinkers have for decaf coffee. It may not be just the lack of buzz that turns them off. Some of them with the right genes may be missing that extra bit of bitterness that alerts them that something good is about to happen.

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