Environmental Chemistry Tip Sheet - Dec. 1997

EMBARGOED FOR RELEASE: Wed., Nov. 26

For further information, contact:

Jim Bohning, 202/872-6041
[email protected]

ENVIRONMENTAL CHEMISTRY TIP SHEET - Dec. 1997

The following research articles will appear in the December issue of Environmental Science & Technology, a monthly peer-reviewed journal published by the American Chemical Society, the world's largest scientific society.

1. SUNFLOWERS FILTER URANIUM, CLEAN UP CONTAMINATED GROUND WATER

The removal of uranium from water in uranium mining areas and in the vicinity of nuclear processing facilities can be accomplished with sunflower plants in a process called rhizofiltration. Certain sunflower plants have a high affinity for uranium and concentrate the metal in their roots. A pilot-scale rhizofiltration system incorporating hydroponically grown sunflowers was used to treat more than 50,000 gallons of groundwater at a former uranium processing plant in Ashtabula, Ohio. The uranium concentration was reduced to less than the Environmental Protection Agency water quality standard before discharge to the environment.

2. MOTHER NATURE'S OUTDOOR AIR CLEANER PROVES A HEALTH PROBLEM FOR INDOOR OFFICES

Called "mother nature's vacuum cleaner" in outside air, the hydroxy radical (OH) in indoor air has received little attention from researchers. Formed from ozone and unsaturated hydrocarbons that can be found in inside office air, indoor OH radicals are highly reactive molecular fragments that are expected to adversely affect the comfort and health of human occupants as well as the service life, function and appearance of their possessions. Ozone can be removed by charcoal filtration, and unsaturated hydrocarbons can be reduced by the judicious selection of products that are used indoors.

3. MEXICAN AUTO EMISSIONS IMPROVE, BUT PROBLEMS STILL EXIST

Analysis of the 1995 exhaust emissions for 24,000 vehicles in Monterrey, Mexico, shows that the introduction of emission controls starting in 1991 has significantly lowered the amount of carbon monoxide, hydrocarbons, and nitrogen oxides discharged into the environment. However, there is a lack of a clear stepwise reduction that would be expected if the new technology was effective and not subject to rapid deterioration which can be caused by tampering or misfueling with leaded gasoline. And emissions from 1991 model year vehicles were almost back up to the pre-controlled models by the time they were measured in 1995. If this loss of effectiveness continues with the current and future models, then fleet turnover rates which do not alter the average age will not allow for any future improvements.

4. EXPOSURE TO PCBs IN RESIDENTIAL INDOOR AIR NEAR A SUPERFUND SITE

A new study shows that polychlorinated biphenyls (PCBs) can persist in residences despite the 20-year ban on their production, even if the home is not located near a significant outdoor source of PCBs. PCB concentrations were measured in indoor and outdoor air at 34 homes surrounding the New Bedford, Massachusetts, harbor during the dredging of highly contaminated harbor sediments that had been declared a superfund site. PCB concentration in outdoor air in harbor areas exceeded that of comparison neighborhoods by a factor of 8, and was among the highest levels of PCBs measured anywhere in recent years. But in almost all cases, indoor air PCB concentrations exceeded that found in outdoor air. No residential indoor air quality standards or guidelines exist for PCBs. All concentrations measured in this study are well below occupational standards, but these standards are not designed to protect human health in the residential environment.

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Environmental Chemistry Tip Sheet (11/00/97) - Geographical Index (Note: The number in parentheses after each location corresponds to the item numbers above.)

Colorado: Denver (3)

Massachusetts: Boston (4), Chelmsford (4), New Bedford (4)

Mexico: Monterrey (3)

New Jersey: Monmouth Junction (1), New Brunswick (1), Red Bank (2)

Ohio: Ashtabula (1)

Washington: Seattle (4)