Monthly Archives: July 2019

Mysterious giant dust particles

Mysterious giant dust particles found at gravity-defying distances
by University of Reading

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“An unknown influence is allowing giant dust particles to spread around the world and could be contributing to global warming, scientists have found.

Large dust particles from the Sahara Desert have been found up to 3500 km away in the Caribbean. These were nearly 50 times bigger than scientists thought was possible to be transported such a distance via global winds.

Dust affects the delicate balance between incoming sunlight and heat emitted from Earth, tropical cyclone development and the formation of clouds. The scientists say the large particles’ role in the atmosphere, with their unexpected long-range effects, should be included in climate models in future.

Professor Giles Harrison, Professor of Atmospheric Physics at the University of Reading, and a co-author of the study, said: “These dust particles are whipped up from the Sahara Desert and carried between continents, and most people know them best when they end up settling on our cars or cause the kind of eerie orange skies we saw a year ago.

“However, existing ideas do not allow for such massive particles travelling in the atmosphere for such vast distances, suggesting that there is some as-yet-unknown atmospheric process or combination of processes keeping them airborne. Charging of the particles and associated electric forces is one avenue being explored.

“This evidence of dust and ash being carried so far is significant because these particles influence radiation transfer around the Earth and carbon cycles in the oceans.”

Role of large dust particles ‘underestimated’

The research, led by the Royal Netherlands Institute for Sea Research (NIOZ), is published today in Science Advances.

Winds carry dust particles from the Sahara west over the Atlantic Ocean. The researchers collected desert dust in floating buoys and underwater sediment traps in five locations in the Atlantic Ocean between 2013 and 2016.

It was previously thought the size of the particles in this cloud ranged from 0.01-0.02mm in diameter, but scientists found particles measuring 0.45mm in samples in the Caribbean.

The scientists argue this means the role of large dust particles, especially quartz, in both cloud formation and the carbon cycle in the oceans has been underestimated. The role of the particles is largely neglected in computer models used to explain and predict climate change because they have not been thought to persist in the atmosphere.

The research also suggests the amount of dust removed from the atmosphere by rain, rather than gravity, is greater than previously assumed. ”


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Uranium in mine dust – health risk

An interesting article on the health risk posed by uranium that is present in mine dust.

Uranium in mine dust - health risk

Uranium in mine dust could dissolve in human lungs
by American Chemical Society

Article found at  –

“New Mexico contains hundreds of historic uranium mines. Although active uranium mining in the state has ceased, rates of cardiovascular and metabolic disease remain high in the population residing close to mines within the Navajo Nation. According to a new study in ACS’ journal Environmental Science & Technology Letters, inhaled uranium in dusts from the mines could be a factor.

Uranium ore is weakly radioactive, which could damage DNA and cause disease. However, the chemical toxicity of uranium may be a greater risk than its radioactivity. In laboratory studies, uranium that was depleted of its most radioactive isotope still caused DNA damage and cell death. Small particles of uranium-containing dust could be inhaled by people and penetrate deep within their lungs. But scientists haven’t studied whether uranium can leach from minerals in the dust into lung fluids and the bloodstream. So Gayan Rubasinghege and colleagues wanted to determine if uranium in dust samples from a mining region in New Mexico could dissolve in simulated lung fluids.

To find out, the researchers collected airborne dust samples from five sites near uranium mines close to communities. They identified minerals in the dust samples, which varied by location. All of the dust samples contained one or more uranium-containing minerals, such as uraninite or carnotite. Then, the researchers exposed two simulated lung fluids—one that mimics the fluid that surrounds lung cells, and another that simulates the acidic environment in lung immune cells that engulf dust particles—to the dust and measured the amounts of uranium dissolved in each fluid. The mineral composition of the dust influenced its solubility, with some minerals dissolving more readily in one fluid than the other. These results indicate that toxicological assessments of mining lands should focus on specific sites, instead of making broad generalizations, the researchers say.”


Medical Express –

“Depleted uranium may post health hazard
A U.S. study suggests exposure to particles of depleted uranium might increase the risk of genetic damage and lung cancer.

Depleted uranium is the material remaining after removal or depletion of the U-238 isotope. With a density about twice that of lead, depleted uranium is ideal for use in military armor and munitions.

But now John Pierce Wise Sr. and colleagues at the University of Southern Maine have discovered depleted uranium dust produced in combat creates potentially frequent and widespread exposure for soldiers and non-combatants inhaling such dust particles.

In their study, the researchers tested the effects of depleted uranium dust on cultures of human lung cells.

“These data suggest that exposure to particulate DU may pose a significant genotoxic risk and could possibly result in lung cancer,” the scientists said.

The study is to be reported in the May 21 issue of the journal Chemical Research in Toxicology.

Copyright 2007 by United Press International”



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Burning Sugarcane

A controversial issue in Florida, USA.  Please follow the link to read the full article.


New Food Economy –

Burning Sugarcane

“Florida sugar companies hit with lawsuit to halt the controversial practice of burning sugarcane

Residents in America’s top sugar-producing county say the burning leads to increased infant mortality, asthma, and “black snow.”

June 6th, 2019 by Sam Bloch

The burning starts in October, when sugarcane companies begin to set fire to nearly 400,000 acres on the shores of Florida’s Lake Okeechobee, clearing away the leaves to prepare the plants for harvest. When the flames die down, machines roll in to chop down the stalks and shunt them off to nearby mills for processing.

For the people who live nearby, the burning means something else. Every year, for eight months, bursts of thick smoke billow from the fields into the air, causing an ash the locals call “black snow” to drift down from the sky. The particles coat their homes, their cars, and their clothes. They’re ingested by children, who develop higher rates of asthma, and by expectant mothers, who are more likely to lose the pregnancy.

That’s according to two residents, Clover Coffie and Jennie Thompson, who on Tuesday filed a federal class-action lawsuit in the Southern District of Florida. The plaintiffs are seeking damages from the negative health effects of burning sugar cane fields, a practice that the South Florida Sun-Sentinel reports has been going on for decades.

The lawsuit accuses U.S. Sugar, Florida Crystals, and the Sugar Cane Growers Cooperative of Florida—three of the country’s largest sugar companies—and 10 other growers and refiners, of negligence, liability for the damages caused by the burning, and trespassing (for the ash that lands on private property). In their complaint, Coffie and Thompson ask the court to force the companies to stop burning, and to set up a medical monitoring program for over 40,000 people—the population of the “affected area,” which comprises three zip codes in Palm Beach County.

“They would be monitoring the health of the residents there who have been exposed to pollutants from sugar cane burning in order to identify and begin to treat any health conditions that are created in that population as a result of the sugar cane burning,” said Zach West, an attorney who filed the suit, at a press conference. “We’re also seeking full reimbursement for the depression of property values in that area related to the sugar cane burning. The costs of such a program are going to be enormous.”

The Sun Sentinel reports West was joined by former Florida state senator Joe Abruzzo and Frank Biden, brother of Joe, both of whom work for the Berman Law Group. Standing with them was Fred Taylor, a former NFL running back who grew up breathing black snow in Belle Glade, Florida, where the town motto is “her soil is her fortune.”

A tall, perennial grass that resembles bamboo, sugarcane is an essential source of the refined sugar we eat in America. The plant accounts for 40 percent of all sweeteners consumed, according to Jack Roney, the director of policy for the American Sugar Alliance. Corn syrup and beet sugar account for the rest.

The crop thrives in tropical climates; in America, it is grown in the Louisiana Delta and the lower Rio Grande Valley in Texas. The primary growing state is Florida, however, where the sugarcane industry took off after the U.S. stopped imports from Cuba in 1960, according to USDA’s Economic Research Service. Today, the Sunshine State is responsible for up to 17 million tons of sugarcane harvest every year, grown principally in the acreage along the southern and southeastern shores of Lake Okeechobee. Palm Beach, where the plaintiffs live, is by far its most productive county. Yet the fields are “so compact that most Florida visitors never even see a sugarcane field,” the state Farm Bureau gloats.

And this is where the burning comes in. During the growing season, from October to April, growers set their fields aflame to rid the plants of leaves and vegetation, leaving “nothing standing but the cane,” as an environmental engineer puts it. That’s partly a matter of harvesting efficiency, but also, burning can evaporate the water in the stalks, which bumps up their sugar content, the lawsuit alleges.

The sugar industry, for its part, says that burning off all that sugar-free biomass isn’t just about getting the most out of the yield, or harvesting more efficiently. Other alternatives, like mulching the leaves, are “just not feasible,” the president of the Sugar Cane Growers Cooperative told the Sun-Sentinel, because leaving them on the ground would smother the next crop growing in the muck. That’s disputed by environmentalists like the Sierra Club, who allege that sugarcane growers in Australia and Brazil have been able harvest without burning, and that there are other uses for the leaves (e.g., creating biofuels).

Clearly, the practice is controversial: Michael Grisham, who leads sugarcane research for the USDA’s Agricultural Research Service, refused to comment to The New Food Economy on the efficacy of pre-harvest burning, saying that while there could be agricultural benefits like higher yields, growers were nevertheless “sensitive” to related health issues. Like, for example, the kidney damage that sugarcane field workers suffer, and respiratory issues suffered by people who come into contact with the smoke. Arturo Rojas, a chemical and environmental engineer, cautioned residents in San Antonio to stay inside during the “May Murkies,” or the annual haze caused by burning sugarcane fields, drifting up from Mexico.

In the complaint, the plaintiffs also allege that the “black snow” from the fires discolors cars, homes, and office buildings, which incurs cleanup costs and tanks property values.

Other effects are more lethal. During the harvest season, the plaintiffs allege, residents breath air concentrated with toxic particles, at a rate that’s 15 times higher than it is in the summer. As a result, mothers fret about “putting their kids to bed at night” while the cane is burning, according to a video the attorneys released. One mother, who has lived in Belle Glade for 23 years, said her four-month-old son has already been diagnosed with asthma. All told, Abruzzo said, there were nearly 700 asthma-related hospitalizations for every 100,000 residents in Palm Beach County, which the Sun Sentinel says is almost five times the state average.

What’s particularly galling, according to Abruzzo, is that this is disproportionately affecting poor people. He says he wasn’t aware of the issue until 2017, when the wind shifted and blew ashes into Boca Raton, causing an uproar among “politically active retirees,” as the Sun-Sentinel put it. Generally, he says, the sugar companies will only burn the fields when the wind blows west, which disperses the ash onto the poorer communities of Belle Glade, Pahokee, and South Bay.”


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Lunar Dust Clouds

And now for a trip to the moon………

Lunar Dust Clouds

Scientists explain formation of lunar dust clouds –

“Physicists from the Higher School of Economics and Space Research Institute have identified a mechanism explaining the appearance of two dusty plasma clouds resulting from a meteoroid that impacted the surface of the moon. The study was published in JETP Letters.

The collision of a meteoroid with the surface of the moon greatly changes the properties of the surrounding dusty plasma system by throwing a large quantity of lunar soil-regolith debris—dust particles measuring 10 to 100 microns—into the otherwise relatively unsullied exosphere.

In 2015, astronomers at the Garden Observatory in Gordola (Switzerland) observed a similar phenomenon when they recorded an optical flash resulting from a meteoroid impacting the moon. An international group of scientists using data from astronomical observations concluded that a fairly large and fast-moving meteoroid had impacted the moon, raising two clouds of unknown composition.

Russian researchers from the Higher School of Economics, Space Research Institute (IKI), Moscow Institute of Physics and Technology, Sternberg Astronomical Institute, and Far Eastern Federal University determined that a meteoroid collision with the surface of the moon produces a shock wave that throws up regolith fragments and droplets of molten material into the surrounding free space. Those fragments and hardened molten droplets rise above the surface of the moon, interact with the electrons in the solar wind and solar radiation, and become electrically charged. Two dusty plasma clouds form as a result—one composed of regolith fragments and a second of hardened droplets of molten material. The differing characteristics of the two clouds make it possible to observe them separately.

Scientists have calculated the main characteristics of the clouds—the speed at which they expand, the size, number density, and electrical charge of the particles in each, and so on. The calculations and observational data matched. It was found that a cloud formed by hardened droplets of molten material expands significantly faster than a cloud formed by regolith fragments.

“Lunar dust is a significant risk factor for spacecraft, equipment, and the astronauts’ health,” explained study co-author, HSE Faculty of Physics Professor, and Space Research Institute Laboratory Head Sergey Popel. “Equipment covered with dust can malfunction. Astronauts carry dust on their spacesuits into the lunar module where it becomes suspended weightlessly in the air, causing them to inhale the particles during their entire return trip to Earth. Therefore, understanding the mechanism by which dusty plasma clouds are formed is important for ensuring the safety of space flights to the moon.””


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