News / Science & Technology

    Tree Bark Shows Global Spread of Toxic Chemicals

    Tree Bark Shows Global Spread of Toxic Chemicalsi
    X
    March 15, 2013 9:14 PM
    The chemicals used to retard fire in consumer products such as furniture and clothing can become toxic pollutants when they wind up in the environment. And they are in the environment - all over the world - in the water, the soil, the plants, and the air. Tracking the spread of these chemicals has been a major challenge, but it just got easier. Erika Celeste reports for VOA on the new technique.
    Tree Bark Shows Global Spread of Toxic Chemicals
    Erika Celeste
    The US Environmental Protection Agency has begun a major new risk assessment of 20 flame-retardant chemicals. These compounds have been widely used for decades in many consumer products, from furniture to sleepwear. But the chemicals are toxic.  And although they are being phased out, they have become a worldwide pollutant and a serious threat to human health.  Measuring their presence in our water, soil, and air has been a major challenge.  But, a new technique promises to make it much easier.

    And they are in the environment all over the world; in the water, soil, plants and the air. Tracking the spread of these chemicals has been a major challenge, but it just got easier.

    It takes less than 90 seconds for a spark to grow to an inferno. Flame retardants can prevent this.

    But Indiana University researcher Amina Salamova points out that when the chemicals evaporate, they become toxic air pollutants.

    On the campus of Indiana University, Amina Salamova studies polybrominated diphenyl ethers [PBDEs], and other chemical environmental pollutants. PBDEs are widely used as flame retardants but have been associated with adverse effects on human health.

    “They can have an effect on neurological development, on reproductive system, and they can effect your thyroid endocrine system,” said Salamova.

    Concerns about those effects have prompted regulatory agencies and some manufacturers to phase out the use of many flame retardant chemicals. But PBDEs can persist for years in the environment, and scientists do not know precisely where or how they spread.

    Novel tool

    That’s why Salamova and her co-researcher Ronald Hites developed a new technique to measure the presence and concentration of flame retardant chemicals in the air, by sampling the bark of trees.  

    “The tree’s ideal because it’s sitting there passively soaking up these compounds out of the atmosphere,” said Hites.

    A tree’s bark provides a large surface area that takes in chemicals as both vapor and particles. Also, because a layer of bark remains on the tree for five years or so before being shed, it provides a unique record of the environment over time.

    Salamova said the tree-bark approach has many advantages over the current, more complex sampling method, which involves pumping air through expensive equipment, and requires plenty of manpower, and electricity.

    “So what I see in future for tree bark is the ability to use this method in developing countries which don’t have a lot of funding for elaborate atmospheric studies. Also we can use this method in remote sites where there is no power,” said Salamova.

    Global initiative

    With the help of the Global Atmospheric Passive Sampling network, an international monitoring initiative, Salamova and Hites received bark samples from 12 locations around the world, including Norway, the Czech Republic, South Africa, Nepal, Indonesia, the United States and Canada.  

    “So this way, you collect about 50 gram of bark, you can collect it from either side of the tree,” said Salamova.

    Researchers use a chisel and hammer to tap out a few pieces of bark, wrap them in foil and ship them back to Indiana University for chemical analysis.

    Pervasive evidence

    Studying those samples in the lab, the researchers found evidence of flame retardants in the atmosphere at all 12 locations. Hites was not surprised to find the highest concentrations at urban sites in Ontario, Canada and around the U.S. Great Lakes.

    What was unexpected was the high level of chemicals in some very remote rural regions of Indonesia and Tasmania.

    “There’s hardly anybody there. It’s really out of the winds of possible industrial sources. But still these compounds are present there at reasonably high levels, they’re slightly below average, but again measurable levels in the tree bark from Tasmania,” said Hites.

    The researchers’ findings, detailed in the journal Environmental Science and Technology, show that these compounds are migrating surprisingly long distances. Salamova says they hope to continue collecting samples to build a global database so scientists and regulatory agencies can understand the pervasiveness of chemical retardants and find ways to remove them from the environment.

    You May Like

    Vietnam Urges US to Lift Lethal Weapons Ban Amid S. China Sea Tensions

    US president’s upcoming visit to Vietnam underscores strength of relationship, and lifting embargo would reflect that trust, ambassador says

    Are US Schools Turning a Blind Eye to Radical Qatari Preachers?

    Parade of radical Islamist clerics using mosque at Qatar’s Education City draws mounting criticism for American universities that maintain satellite branches there

    Why Islamic State Is Down But Not Out

    Despite loss of territory, group’s ferocious attacks over past three months seen as testimony to its continued durability and resourcefulness

    This forum has been closed.
    Comment Sorting
    Comments
         
    by: Rie K.Maegawa from: Japan
    March 31, 2013 1:50 AM
    We should rate this experiment highly from the following points. First, this laboratory and field work does not kill any living creatures. Secondly, the samples are really widely collected. As the result, the researchers have found the unexpected high leverl of the chemicals in the very remote rural regions of Indonesia and Tasmania. Building a global database for the data is significant.

    by: Chinara from: Azerbaijan
    March 19, 2013 8:59 PM
    Is it possible to conduct tests on dioxin by this method? As dioxin also is very toxic and persistent pollutant and accumulates in the tissue from all type of environment.

    by: cleanair from: Tasmania
    March 17, 2013 8:38 AM
    Thank you to the researchers who have discovered this process.
    I live in Tasmania. There are about half a million people live here.
    These results are interesting because our CSIRO tells us we have the cleanest air in the world.
    In Response

    by: Ian from: USA
    March 18, 2013 11:28 AM
    You may actually still have the cleanest air in the world.
    It is just the whole world's air getting worse

    by: Kitagawa Keikoh from: Jiyugaoka, JPN
    March 15, 2013 8:00 PM
    We are threatening from China's PM2.5 in Japan. They are the worst pollution producer in the world. They don't have enough technology to prevent pollutions and they are wasting energy. That is a new weapon of harasment for neighbor countries.

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    Displaced By War, Syrian Artist Finds Inspiration Abroadi
    X
    May 02, 2016 1:36 PM
    Saudi-born Syrian painter Mohammad Zaza is among the millions who fled their home for an uncertain future after Syria's civil war broke out. Since fleeing Syria, Zaza has lived in Lebanon, Egypt, Jordan and now Turkey where his latest exhibition, “Earth is Blue like an Orange,” opened in Istanbul. He spoke with VOA about how being displaced by the Syrian civil war has affected the country's artists.
    Video

    Video Displaced By War, Syrian Artist Finds Inspiration Abroad

    Saudi-born Syrian painter Mohammad Zaza is among the millions who fled their home for an uncertain future after Syria's civil war broke out. Since fleeing Syria, Zaza has lived in Lebanon, Egypt, Jordan and now Turkey where his latest exhibition, “Earth is Blue like an Orange,” opened in Istanbul. He spoke with VOA about how being displaced by the Syrian civil war has affected the country's artists.
    Video

    Video Ethiopia’s Drought Takes Toll on Children

    Ethiopia is dealing with its worst drought in decades, thanks to El Nino weather patterns. An estimated 10 million people urgently need food aid. Six million of them are children, whose development may be compromised without sufficient help, Marthe van der Wolf reports for VOA from the Metahara district.
    Video

    Video Little Havana - a Slice of Cuban Culture in Florida

    Hispanic culture permeates everything in Miami’s Little Havana area: elderly men playing dominoes as they discuss politics, cigar rollers deep at work, or Cuban exiles talking with presidential candidates at a Cuban coffee window. With the recent rapprochement between Cuba and United States, one can only expect stronger ties between South Florida and Cuba.
    Video

    Video California Republicans Weigh Presidential Choices Amid Protests

    Republican presidential candidates have been wooing local party leaders in California, a state that could be decisive in selecting the party's nominee for U.S. president. VOA's Mike O’Sullivan reports delegates to the California party convention have been evaluating choices, while front-runner Donald Trump drew hundreds of raucous protesters Friday.
    Video

    Video Kurdish Football Team Helps War-Torn City Cope

    With the conflict still raging across much of Turkey’s predominantly Kurdish southeast, between the rebel PKK and the Turkish state, many Kurds are trying to escape the turmoil by focusing on the success of their football team Amedspor in Diyarbakir. The club is increasingly becoming a symbol for Kurds, not only in Diyarbakir but beyond. Dorian Jones reports from southeast Turkey.
    Video

    Video ‘The Lights of Africa’ - Through the Eyes of 54 Artists

    An exhibition bringing together the work of 54 African artists, one from each country, is touring the continent after debuting at COP21 in Paris. Called "Lumières d'Afrique," the show centers on access to electricity and, more figuratively, ideas that enlighten. Emilie Iob reports from Abidjan, the exhibition's first stop.
    Video

    Video Pakistani School Helps Slum Kids

    Master Mohammad Ayub runs a makeshift school in a public park in Islamabad. Thousands of poor children have benefited from his services over the years, but, as VOA's Ayesha Tanzeem reports, roughly 25 million school-age youths don't get an education in Pakistan.
    Video

    Video Florida’s Weeki Wachee ‘Mermaids’ Make a Splash

    Since 1947, ‘mermaids’ have fascinated tourists at central Florida’s Weeki Wachee Springs State Park with their fluid movements and synchronized ballet. Performing underwater has its challenges, including cold temperatures and a steady current, as VOA’s Lin Yang and Joseph Mok report.
    Video

    Video Somali, African Union Forces Face Resurgent Al-Shabab

    The Islamic State terror group claimed its first attack in Somalia earlier this week, though the claim has not been verified by forces on the ground. Meanwhile, al-Shabab militants have stepped up their attacks as Somalia prepares for elections later this year. Henry Ridgwell reports there are growing frustrations among Somalia’s Western backers over the country’s slow progress in forming its own armed forces to establish security after 25 years of chaos.
    Video

    Video Documentary Tells Tale of Chernobyl Returnees

    Ukraine this week is marking the 30th anniversary of the world's worst nuclear accident, at the Chernobyl nuclear power plant. Soviet officials at first said little about the accident, but later evacuated a 2,600-square-kilometer "exclusion zone." Some people, though, came back. American directors Holly Morris and Anne Bogart created a documentary about this faithful and brave community. VOA's Tetiana Kharchenko reports from New York on "The Babushkas of Chernobyl." Carol Pearson narrates.
    Video

    Video Nigerians Feel Bite of Buhari Economic Policy

    Despite the global drop in the price of oil, Nigerian President Muhammadu Buhari has refused to allow the country's currency to devalue, leading to a shortage of foreign exchange. Chris Stein reports from Lagos businessmen and consumers are feeling the impact as the country deals with a severe fuel shortage.
    Video

    Video  Return to the Wild

    There’s a growing trend in the United States to let old or underused golf courses revert back to nature. But as Erika Celeste reports from one parcel in Grafton, Ohio, converting 39 hectares of land back to green space is a lot more complicated than just not mowing the fairway.

    Special Report

    Adrift The Invisible African Diaspora