- Poisonous Substances Produced By Blue-Green
Algae Can Attack Liver
- A new, more effective method for destroying
potentially deadly toxins called microcystins that can be found in drinking
water has been announced by researchers in Scotland. Microcystins are produced
by blue-green algae, which can grow in reservoirs, lakes and other bodies
of water that are used for municipal drinking water. Blue-green algae,
often referred to as pond scum but known scientifically as cyanobacteria,
can be found in all areas of the world.
- The detoxification method, which uses
titanium dioxide and light to destroy the toxins, is described in the Jan.
26 web edition of the journal Environmental Science & Technology, a
peer-reviewed publication of the American Chemical Society, the world's
largest scientific society. The research article is scheduled to appear
in the March 1 print issue of the semi-monthly journal.
- When titanium dioxide, a white powder
commonly used in sun creams and paints, is added to water and exposed to
light, it becomes active and destroys the toxins.
- Known specifically as microcystin-LR
(cyanobacterial hepatotoxins), the toxins are "very difficult to destroy"
with normal water purification methods, according to the article's lead
author, Linda Lawton, Ph.D., of the Robert Gordon University in Aberdeen,
Scotland. Acute exposure to the toxic microcystins produced by the algae
can cause liver damage and is fatal in extreme cases, according to the
article. Approximately 50 dialysis patients in Brazil died in 1996 "due
to the use of microcystin-contaminated water in their treatment,"
notes Lawton. Long-term exposure is thought to contribute to liver cancer,
the article states.
- In the U.S., the risk of humans getting
ill or dying from microcystins in drinking water is relatively low, says
Wayne Carmichael, Ph.D., a professor of aquatic biology and toxicology
at Wright State University in Dayton, Ohio, and a leading expert on the
subject of toxic cyanobacteria. However, he adds, "a recent study
of municipal water supplies in the U.S. and Canada found a few cases where
microcystin levels were higher than guidelines established by the World
Health Organization." One part per billion, or one microgram per liter,
is the WHO standard.
- The detoxification method developed by
the Scottish researchers is quicker and more effective than currently used
methods, claims Lawton. "Costs are comparable with other methods,"
she adds, "but if sunlight could be used, it would greatly reduce
costs." The laboratory research was done using a xenon UV lamp.
- Further testing needs to be done, according
to the article, to evaluate the performance of the new method in the field
and to confirm that water treated with titanium dioxide is safe to drink.
- A nonprofit organization with a membership
of nearly 159,000 chemists and chemical engineers, the American Chemical
Society publishes scientific journals and databases, convenes major research
conferences, and provides educational, science policy and career programs
in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.