In the Lab
Global Warming May Increase
Atlantic Hurricane Intensity
Global warming may be a key factor in the emergence of stronger hurricanes in the Atlantic Ocean, according to a study announced Feb. 28 by atmospheric scientists. This trend is confined to the Atlantic, however, researchers found.
Scientists at the University of Wisconsin-Madison (UW-Madison) and the National Climatic Data Center (NCDC) of the National Oceanic and Atmospheric Administration (NOAA) reported their findings in the journal Geophysical Research Letters.
James Kossin, a research scientist at UW-Madison’s Cooperative Institute for Meteorological Satellite Studies, said researchers analyzed an NCDC archive that holds global satellite information for the years 1983 through 2005.
“The data says that the Atlantic has been trending upwards in hurricane intensity quite a bit,” Kossin said. “But the trends appear to be inflated or spurious everywhere else, meaning that we still can’t make any global statements.”
Sea-surface temperatures may be one reason why greenhouse gases are exacting a unique toll on the Atlantic Ocean, Kossin said. Hurricanes need temperatures of around 27 degrees Celsius (81 degrees Fahrenheit) to gather steam. On average, the Atlantic’s surface is slightly colder than that while other oceans, such as the Western Pacific, are naturally much warmer.
“The average conditions in the Atlantic at any given time are just on the cusp of what it takes for a hurricane to form,” Kossin said. “So it might be that imposing only a small (man-made) change in conditions creates a much better chance of having a hurricane.”
For more information, contact Kossin through this site, http://www.ssec.wisc.edu/~kossin.
Air Pollutants May Change
Chemically, Gaining Toxicity
Carnegie Mellon University researchers urge government officials to adopt new ways of measuring and regulating the fine particulate matter in smoke and soot.
In a March 2 article published in the journal Science, professors Allen L. Robinson and Neil M. Donahue report a new conceptual model for how particulate matter behaves in the atmosphere that raises new questions about current regulations.
The research found new chemical processes that occur after soot and gaseous pollutants are emitted from cars and trucks, changing the chemical and physical properties of the soot particles and creating new particulate matter. These new particles are potentially more toxic and may have a stronger influence on cloud formation that can alter the global climate.
“One of our key findings is that this chemical processing leads to more particulate matter in the air, meaning that regulators are likely underestimating how sources such as cars and trucks contribute to pollution,” said Robinson, an associate professor of mechanical engineering and engineering and public policy.
Accounting for these new processes improves the predictions of the models federal and state governments use to develop regulations, the researchers said.
“A second important finding is that the properties of this new particulate matter are different than we previously thought and potentially more toxic,” added Donahue, an associate professor of chemical engineering and chemistry.
A third key implication has to do with how the chemical process leads to a spreading of pollution over a larger geographic region.
Fine particulate matter such as smoke or dust form droplets in clouds and affect how much sun is able to pass through the cloud to earth, as well as the amount of moisture that is returned to earth. Both clouds and sunlight play key roles in climate change, the researchers said.
“The new mechanism we found changes the chemical properties of particles, making them more likely to participate in cloud formation. Therefore, particulate matter may be having a stronger influence on global climate than previously thought,” Donahue said.
For more information, contact Robinson at this Web site: http://www.epp.cmu.edu/httpdocs/people/bios/robinson.html
Warming Trend Could Make
Loggerhead Turtles Extinct
North American marine turtles are at risk if global warming occurs at predicted levels, according to scientists from the University of Exeter in England. An increase in temperatures of just one degree Celsius could completely eliminate the birth of male turtles from some beaches, while a rise of three degrees Celsius would lead to extreme levels of infant mortality and declines in nesting beaches across the United States.
This research, published in March in Global Change Biology, analyzes 26 years of loggerhead turtle nesting and climate data and compares the findings with models for future temperatures. The study shows just how vulnerable marine turtle populations are to changes in temperature.
The sex of marine turtle hatchlings is determined by the temperature of eggs during incubation, with warmer temperatures producing females and cooler conditions producing males. Temperatures during nesting also need to be at the right level for eggs to develop healthily and hatch successfully.
“We’re concerned that populations that are already predominantly female could become 100 percent female if temperatures increase by just one degree. This is a major issue for nesting populations further south, in Florida, for example, where males are already in short supply,” said Brendan Godley of the University of Exeter’s School of Biosciences.
In Florida, about 90 percent of hatchlings are female compared to 42 percent male in North Carolina. A decline in male turtles in northern populations, as a result of global warming, could potentially impact marine turtles across the continent.
Loggerheads are considered endangered by The World Conservation Union. The study was carried by the University of Exeter in partnership with the Bald Head Island Conservancy and the North Carolina Wildlife Resources Commission.
For more information, visit the site http://www.exeter.ac.uk/news/newsturtle2.shtml
Study: Toxic Substances Disrupt
Cells in Central Nervous System
Low levels of toxic substances cause critical stem cells in the central nervous system to prematurely shut down, according to a study published on Feb. 6 in the on-line journal PLoS Biology.
This research, which is the first to identify a common molecular trigger for the effects of toxicant exposure, may give scientists new insights into damage caused by toxicant exposure and methods of evaluating chemical safety.
While scientists know that certain chemicals such as lead and mercury have adverse effects on the body, the precise molecular mechanism by which many of these substances cause harm remains uncertain. This makes it more difficult to concretely link individual toxic substances with specific diseases or determine whether a chemical is toxic.
“We have discovered a previously unrecognized regulatory pathway on which chemically diverse toxicants converge and disrupt normal cell function,” said University of Rochester biomedical geneticist Mark Noble, Ph.D., senior author of the study.
Noble and his colleagues exposed brain cells to low levels of lead, mercury and paraquat, one of the most widely used herbicides in the world. These cells, called glial progenitors, are advanced-stage stem cells that are critical to the growth, development and normal function of the central nervous system. The activity of cells is regulated by molecular pathways -- or controlled chemical reactions -- normally set off when substances bind to receptors on the cell’s surface. These compounds turned off specific sets of receptors and prompted a molecular chain reaction that causes the cells to shut down and stop dividing.
“If this disruption occurs during critical developmental periods, like fetal growth or early childhood, it can have a significant impact,” Noble said.
The findings are part of a growing number of discoveries that indicate that certain developmental syndromes may be the result of disruption in stem cell function.
There are tens of thousands of synthetic industrial chemicals, pesticides, metals and other substances for which toxicological information is limited or nonexistent. By identifying a molecular target that is shared by toxic substances, this discovery may give scientists a method to rapidly evaluate compounds for potential health risk.
For more information, contact Noble through this site, http://www.urmc.rochester.edu/GEBS/faculty/Mark_Noble.htm.
Researchers Seek Cause
Of Honey Bee Die-Off
Researchers continue to study a phenomenon dubbed the Colony Collapse Disorder (CCD) that has resulted in a die-off of honey bees around the country, causing a ripple effect that is impacting crops dependent on bee pollination.
“This has become a highly significant yet poorly understood problem that threatens the pollination industry and the production of commercial honey in the United States,” said Maryann Frazier, apiculture extension associate in Penn State’s College of Agricultural Sciences, in a college press release. “Because the number of managed honey bee colonies is less than half of what it was 25 years ago, states such as Pennsylvania can ill afford these heavy losses.”
A working group of university faculty researchers, state regulatory officials, cooperative extension educators and industry representatives is working to identify the cause of Colony Collapse Disorder . Participating organizations include Penn State, the U.S. Department of Agriculture, the agriculture departments in Pennsylvania and Florida, and Bee Alert Technology Inc., a technology transfer company affiliated with the University of Montana.
“Preliminary work has identified several likely factors that could be causing or contributing to CCD,” said Dennis vanEngelsdorp, acting state apiarist with the Pennsylvania Department of Agriculture. “Among them are mites and associated diseases, some unknown pathogenic disease and pesticide contamination or poisoning.”
Initial studies of dying colonies revealed a large number of disease organisms present, with no one disease being identified as the culprit. Areas being studied as potential factors in CCD include: chemical residue in wax, food stores and bees; known or unknown pathogens in the bees and brood; parasite load in the bees and brood; nutritional fitness of adult bees; level of stress in adult bees; and lack of genetic diversity and lineage of bees.
Ongoing case studies and surveys of beekeepers experiencing CCD have found a few common management factors, but no common environmental agents or chemicals have been identified.
A report on Colony Collapse Disorder can be found on the Mid-Atlantic Apiculture Research and Extension Consortium Web site at http://maarec.org.
Chemical Exposure Linked
To Obesity in Offspring Mice
Environmental chemicals found in everyday plastics and pesticides may predispose people to obesity, according to a University of Missouri-Columbia (MU) scientist.
Frederick vom Saal, professor of biological sciences in MU’s College of Arts and Science, has found that when fetal mice are exposed to these chemicals, the way their genes function may be altered to make them more prone to obesity and disease.
“Certain environmental substances called endocrine-disrupting chemicals can change the functioning of a fetus’s genes, altering a baby’s metabolic system and predisposing him or her to obesity. This individual could eat the same thing and exercise the same amount as someone with a normal metabolic system, but he or she would become obese, while the other person remained thin,” vom Saal said.
Using lab mice, vom Saal studied the effects of endocrine-disrupting chemicals, including bisphenol-A.
According to his findings, presented in February at the 2007 annual meeting of the American Association for the Advancement of Science, endocrine-disrupting chemicals cause mice to be born at very low birth weights and then gain abnormally large amounts of weight in a short period of time. Vom Saal followed the mice as they got older and found that these mice were obese throughout their lives. He said studies of low-birth-weight children have shown a similar overcompensation after birth, resulting in lifelong obesity.
“The babies are born with a low body weight and a metabolic system that’s been programmed for starvation. This is called a ‘thrifty phenotype,’ a system designed to maximize the use of all food taken into the body,” vom Saal said.
More research must be done to determine which chemicals cause this effect.
In the experiment, pregnant mice were fed physiologically relevant, nontoxic doses of estrogenic chemicals. In male mice born, this led to a permanent increase in prostate size, changes in enzyme activity and steroid receptor numbers in a number of organs, a decrease in sperm production, and increased aggressiveness. In female offspring, changes in neuroendocrine and uterine function as well as behavior occurred.
According to vom Saal, there are approximately 55,000 human-made chemicals in the world, and 1,000 of those might fall into the category of endocrine-disrupting. These chemicals are found in common products, from plastic bottles and containers to pesticides and electronics.
For more information, contact vom Saal through this Web site, http://endocrinedisruptors.missouri.edu/vomsaal/vomsaal.html
Old Industrial Waste Site
Returned to Productive Use
A successful pilot project involving planting of shrubs on a former industrial waste site yielded stronger results than expected, with the healthy shrubs harvested and transported for final use at an electric power facility in Lyons Falls, N.Y.
Researchers at the State University of New York (SUNY) College of Environmental Science and Forestry (ESF) harvested shrub willows from this land, known as the Solvay Settling Basins and owned by Honeywell International. The basins contain the byproduct of soda ash production conducted by a previous industrial operation.
“We're using society’s castoffs, residuals such as biosolids and yard waste mulch, to improve the quality of the soil,” said Douglas J. Daley, director of the ESF-based SUNY Center for Brownfield Studies in Syracuse, N.Y. “This is a system that helps close the loop, using waste products to improve the soil and benefit both the economy and the environment.”
The current harvest, announced on Jan. 31, marks the first time productive willow shrubs have been grown where former industrial operations resulted in soil with a high pH content. Honeywell fertilized the site several years ago with biosolids that were the byproducts of a wastewater treatment operation.
Daley said the healthy willow crop demonstrates the long-term success of using biosolids and yard waste mulch in brownfield redevelopment projects.
During the process, the shrubs are cut, stacked, weighed, sampled for moisture and energy content, chipped and transported to the Lyonsdale Biomass Plant in Lyons Falls, N.Y., for use in its 19-megawatt wood-fired energy plant.
The rapidly growing shrubs were planted in spring 2004 as part of a pilot project to develop a living cover for the Solvay Settling Basins. More than 35,000 willows have been planted.
Prior to harvesting the shrubs, willow chips were tested at an independent New York state certified laboratory. There were no detections of mercury, chlorobenzenes or other hazardous compounds.
For more information on the project, go to http://www.esf.edu.
Purifiers May Pollute Air
Even More, Study Shows
Indoor air purifiers that produce even small quantities of ozone may actually make the air dirtier when used at the same time as household cleaning products, scientists at University of California, Irvine (UCI) have discovered.
Ozone emitted by purifiers reacts in the air with unsaturated volatile organic compounds such as limonene – a lemon-scented chemical added to cleaning supplies – to create additional microscopic particles, scientists found. Certain ionic purifiers emit ozone as a byproduct of ionization used for charging airborne particles and electrostatically attracting them to metal electrodes. Ozonolysis purifiers emit ozone at higher levels to supposedly oxidize volatile organic compounds in the air. This research appeared online on Feb. 21 in Environmental Science and Technology.
“These air purifiers can not only elevate the level of ozone, a formidable air pollutant in itself, but also increase the amount of harmful particulate matter in indoor air,” said Sergey Nizkorodov, assistant professor of chemistry at UCI and co-author of the study.
High levels of airborne particles can aggravate asthma and cardiovascular problems, and have been linked to higher death and lung cancer rates. Excess ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation.
Nizkorodov and students Ahmad Alshawa and Ashley Russell conducted their experiment in a sparsely furnished office with a floor area of about 11 square meters. They placed an ozone-emitting air purifier in the middle of the room along with a large fan to better mix the air. At timed intervals, limonene vapor was injected in the room. Samples of the air were taken about one meter from the purifier and analyzed for ozone and particulate matter levels.
The researchers tested two types of air purifiers – a commercial ionic purifier that emits about 2 mg of ozone per hour, and an ozonolysis purifier that emits approximately 100 mg of ozone per hour.
Continuous operation of the ionic purifier without limonene resulted in a slight reduction in the average particle concentration, while operation of the ozonolysis purifier resulted in no detectable effect on the particle level. When limonene was added to the room, the particle concentration increased, on some occasions up to 100 times the original level. Adding limonene to the room when a purifier was not operating produced little change in the particle level.
A previous study by Nizkorodov found that in a small, poorly ventilated room, an indoor air purifier that produces even a few milligrams of ozone per hour can create an ozone level that exceeds public health standards (see “Study: Indoor Air Purifiers That Produce Ozone Are Unsafe,” an article in the May 2006 archives of http://www.eponline.com).
For more information, go to http://www.chem.uci.edu/faculty/nizkorod.
Disappearing Canadian Tundra
Tied to Global Warming Trend
As global temperatures rise, some landscape changes may occur faster than originally thought, based on a study of Northern Canada’s disappearing tundra.
A study by Ryan Danby, a biologist with the University of Alberta, showed that coniferous trees are invading Canada’s tundra as a result of changing climate. The study, published in the March issue of Journal of Ecology, analyzed changes in the density and altitude of treeline forests in southwestern Yukon going back 300 years.
“The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes,” said Danby. “But what our data indicates is that there was an upslope surge of trees in response to warmer temperatures. It’s like it waited until conditions were just right and then it decided to get up and run, not just walk.”
The study used tree rings to date the year of establishment and death of spruce trees and reconstruct changes in treeline vegetation. On warm, south-facing slopes, the treeline advanced as much as 278 feet in elevation. Tree density increased as much as 65 percent on cooler, north-facing slopes. At all locations, a rapid change in response to climate warming occurred in the mid-20th century.
“The mechanism of change appears to be associated with occasional years of extraordinarily high seed production – triggered by hot, dry summers – followed by successive years of warm temperatures favorable for seedling growth and survival,” said Danby.
Another possible factor is the “positive feedback” associated with the decrease in the Arctic ice cap. As the treeline advances, the reflectance of the land surface declines because coniferous trees absorb more sunlight than the tundra. This light energy is then re-emitted to the atmosphere as heat, adding to warming and further fueling the advance of the treeline.
The treeline shift may have adverse impacts on tundra species such as caribou and wild sheep, which will also be forced upwards as tundra habitats disappear. Caribou and sheep populations have already declined across southwestern Yukon.
To access the published article, go to http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2745.2006.01200.x.
This article originally appeared in the 05/01/2007 issue of Environmental Protection.