health effects

Global Light Pollution

October 14, 2021 By EarthWise 1 Comment

Light pollution is excessive or obtrusive artificial light. It’s a consequence of industrial civilization. Too much artificial light can cause a host of problems, including disrupting ecosystems, causing adverse health effects, and wasting energy.

According to a new study led by researchers from the University of Exeter in the U.K., global light pollution has increased by at least 49% over 25 years. But this figure only includes light visible via satellites. Scientists estimate that the true increase may be significantly higher – up to 270% more globally.

That’s because there is a hidden impact of LED technology that isn’t accounted for in the satellite data. LEDs emit more blue light than previous lighting technologies, but satellite sensors fail to pick up this blue light. This leads to a large underestimate of global light pollution.

The researchers examined light pollution from 1992 to 2017. They found persistently increasing light pollution in Asia, South America, Oceania and Africa. In Europe, detected light increased until around 2010, after which it leveled off. In North America, artificial light appears to be on the decline. However, the researchers point out that the satellites inability to detect blue light of LEDs means that light pollution has likely actually increased in most locations.

Light pollution has widespread impacts on both animals and plants. For example, light pollution can confuse the migratory patterns of animals and change predator-prey relationships. It’s also been shown to cause trees to bud earlier in spring.

While there’s no off switch for the planet, there are ways that we could reduce the amount of light drastically with little impact on our lives.

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Rapid increase in global light pollution

Photo, posted November 2, 2008, courtesy of Timothy Tsui via Flickr.

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Aluminum And Deodorants | Earth Wise

October 2, 2020 By EarthWise Leave a Comment

Aluminum is the third most common element in the earth’s crust. That element and its compounds are contained in numerous foods and products intended for consumers. Aluminum can occur naturally in certain foods and it can be a part of food additives. Apart from that, it is also possible for aluminum to transfer to food from packaging and tableware. We also can take in aluminum from cosmetic products like whitening toothpaste, lipsticks, particles in sunscreens, and in the form of aluminum chlorohydrate in antiperspirants.

The concern about aluminum intake is related to its effects on the nervous system, on the mental and motor development of children, and upon possible negative effects on the kidneys and bones. When aluminum is ingested via food, its toxicity is low and for healthy people, the kidneys do a good job of excreting it. However, people with chronic kidney disease may not be able to get rid of aluminum as readily and it can accumulate in the body.

Six years ago, a study looked at the amount of aluminum absorbed through the skin from the use of antiperspirants, but the data at that time was considered to be unreliable and a need for further research was identified.

Recently, the results of two new studies have been published by a German research institute that quantifies the absorption of aluminum salts through the skin. The results were that significantly less aluminum is absorbed through the skin than previously calculated and that a significant absorption of aluminum from antiperspirants is unlikely.

The total burden of aluminum from all sources can be high among some population groups, but it appears that use of aluminum-containing antiperspirants is not an important contribution to that burden.

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Aluminium in antiperspirants: Low contribution to the total intake of aluminium in humans

Photo courtesy of NutritionFacts.org.

Earth Wise is a production of WAMC Northeast Public Radio.

PFAS In The Food Chain | Earth Wise

July 8, 2020 By EarthWise Leave a Comment

Per- and polyfluoroalkyl substances (PFAS) are a family of human-made chemicals that have been manufactured and used in a variety of industries around the globe. PFOA and PFOS have been the most extensively produced and the most extensively studied of these chemicals.

Exposure to PFAS has been linked to a host of adverse health effects, including thyroid hormone disruption and cancer.

PFAS compounds can be found in such things as non-stick cookware, stain-resistant carpets, water-repellent outdoor gear, and food packaging, like fast food wrappers and microwave popcorn bags.

According to a new study, researchers from North Carolina State University have found PFAS substances in every step of the Yadkin-Pee Dee River food chain, even though the river doesn’t have a known industrial input of these compounds.

The team collected water, sediment, algae, plant, insect, fish, crayfish, and mollusk samples at five sites along the river and analyzed them for 14 different PFAS compounds. Nearly every sample tested contained PFAS compounds. Biofilm contained the largest concentrations of 10 of the 14 PFAS compounds measured. Insects, which primarily eat biofilm, had the greatest accumulation of PFAS compounds of all the living taxa the researchers sampled.

When PFAS compounds are present at every step of the food chain, the compounds accumulate at each step leading to greater concentrations in animals that sit higher on the food chain – including humans. This is known as biomagnification.

Studies like this that reveal how prevalent PFAS can be within ecosystems without an industrial input highlight the need for further research into how these compounds affect the environment and human health.

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PFAS present throughout the Yadkin-Pee Dee river food chain

Photo, posted May 24, 2011, courtesy of the U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Breaking Down Forever Chemicals

October 25, 2019 By EarthWise Leave a Comment

One of the toughest classes of pollutants are per- and polyfluoralkyl substances, or PFAS, as they are known. PFAS are often called “forever chemicals” because they are extremely long-lasting and difficult to clean up. They are found in household products including non-stick pans, dental floss, water-repellent fabrics, and many others. They can be found extensively in U.S. waterways and soil.

PFAS move through the food chain, accumulating in humans at levels that scientists say can cause adverse health effects. While these have not been definitively proven, there is evidence that higher cholesterol levels, cancer, thyroid disruption, and low infant birth rates are all associated with PFAS ingestion.

PFAS are difficult to get rid of because their carbon-fluorine covalent bonds are some of the strongest in organic chemistry. Researchers at Princeton University have been studying a process known as Feammox in which ammonium breaks down in acidic, iron-rich soils in New Jersey wetlands and similar locations. They found that this reaction takes place when a bacterium called Acidimicrobium A6 is present.

Using gene-sequencing techniques, they found that the microbe has characteristics that could help break down carbon-fluorine bonds, and therefore break down PFAS. In tests using microbe-loaded soil samples, they found that the bacterium removed 60% of PFAS pollutants within 60 days.

The research has been published in the journal Environmental Science and Technology and the team is now testing the bacterium’s effectiveness over different time-spans in lab conditions before testing it in the field.

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