UC Toxics News: Spring/Summer 2000
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2000 Symposium Focused on Toxics in the 21st Century by Mika Pringle Tolson |
The 13th Annual TSR&TP Research Symposium at the
Shelter Pointe Hotel in San Diego featured morning poster sessions of TSR&TP-supported
research, and an afternoon panel of four students who spoke about the future
of toxic substances.
 Peter Sinsheimer addresses the audience
with the three other panelists (left to right) Rosemary Castorina, Craig
Wheelock, and James Gray at the TSR&TP Symposium in San Diego.
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Peter Sinsheimer, a doctoral candidate in Urban Planning at UCLA (and Occidental College), spoke first on alternatives to dry cleaning, one of the most polluting, and therefore regulated small businesses in the United States.
Sinsheimer said that more than 75% of dry cleaners today are not in compliance with regulations. He and his research team began trials of professional wetcleaning in 1995 as an alternative to traditional perchloroethylene (PCE) cleaning methods. Wetcleaning uses computer-controlled washers to clean clothing in water with special detergents and additives. Sinsheimer's group found that wetcleaning is a very viable alternative for business. Customer satisfaction is good, and costs are generally lower for wetcleaners than drycleaners. Absolute costs, yearly equipment expenses, and energy use are 10-30% lower. An added benefit is that wetcleaners do not have to pay for PCE emissions abatement and control equipment. However, wetcleaning requires more technical training and there's a learning curve for new wetcleaners. Problem garments increase initially, but they return to the same or lower levels than drycleaning within the first year. Cleaner by Nature, a privately owned commercial wetcleaner in the Los Angeles area that Sinsheimer has been working with, has opened a second facility and is continuing to grow, demonstrating that pollution prevention technologies can significantly reduce contaminant releases into the environment.
The second speaker was Rosemary Castorina, a doctoral student in Environmental Health Sciences at UC Berkeley. Her research on children's environmental health is at the forefront of future issues in toxics. Castorina said that children are no longer considered to be the equivalent of little adults in toxicological risk assessments. The lack of accurate data on exposures for kids has impeded public health polices to protect them.
The Salinas Valley, site of Rosemary
Castorina's research.
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A 1997 Executive Order from President Clinton directed federal agencies to research children's exposures and established research centers focusing on children's environmental health. Pesticide production has increased substantially since WWII, and California accounts for 25% of all agricultural pesticide use in the United States. Because homes may be contaminated with pesticides, children have an increased risk of exposure due to their proximity to floors and their tendency to explore the world through their mouths. Castorina's research will study pregnant women who are receiving prenatal care at community clinics in the Salinas Valley, a predominantly agricultural region. She will follow the children from birth to age two. Her study aims to determine levels of organophosphate pesticide exposure, assess if and how the kids get exposed, determine the levels of allergens such as mold and pollen in their homes, and evaluate if learning ability is affected by pesticide and/or allergen exposure.
Craig Wheelock, a doctoral student in Agriculture and
Environmental Chemistry at UC Davis, spoke about the changing role of agrochemicals
in the 21st century. He said the US uses a third of all pesticides worldwide,
translating to 1 billion pounds and $11.3 billion spent annually. The changing
face of pesticides in the 21st century will include a dramatic increase in the
use of genetically modified organisms (GMOs), a shift in the type of pesticides
used from organophosphates to pyrethroids, which are less toxic to humans, and
increased reliance on integrated pest management practices. These changes may
decrease the risks to humans, but they also pose a greater threat to the environment.
Pyrethroids are much more toxic to aquatic organisms than organophosphates.
In addition, we are now faced with simultaneous exposures to multiple pesticides,
and we do not know what their effects may be. Wheelock's research group is studying
multiple pesticide exposures in fish, combinations of carboxylesterases with
organophosphates and pyrethroids, which will be important in understanding the
future toxicity of agrochemicals.
The final speaker, James Gray, doctoral student in Civil
& Environmental Engineering at UC Berkeley, addressed our future water supply.
California's
growing population and increasing demand for water has made reuse of domestic
wastewater a likely solution. But there are concerns about hormones and pharmaceuticals
in wastewater. Traditional removal of contaminants in wastewater using particle
filtering does not work for hormones.
Gray said that over the last 50 years, the field of
toxicology has moved from studies of acute toxicity from high doses to studies
of chronic toxicity (e.g. cancer) from long-term exposure. In the 21st century,
toxicologists will become more focused on smaller concentrations of chemicals
in the environment and more subtle endpoints. Toxicological research has been
dominated by the EPA priority pollutants, which are easily analyzed using gas
chromatography and classical techniques. Polar organic compounds such as pharmaceuticals,
hormones, and disinfection byproducts have been largely ignored because they
were difficult to study. New techniques in mass spectrometry have now made them
easier to analyze. Gray's research will look at the fate and transport of these
compounds in surface waters. It is not known whether pharmaceuticals and hormones,
or combinations of them may be an ecological or human health threat. More interdisciplinary
research will be necessary to determine the benefits and risks of reusing domestic
wastewater.
At the conclusion, the audience and panelists discussed
linking policy to science and how scientists will deal with complex mixtures
of toxics in the environment. The discussion was continued on the TSR&TP
web forums, which are available to anyone seeking to comment.
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