EPA grant to UC engineering makes for a better environment

A University of Cincinnati researcher studies methods for removing toxins from water with a new grant from the U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency (USEPA) has awarded nearly $700,000 to Dionysios Dionysiou and coworkers to study processes used to purify drinking water.

The USEPA awarded the grant of $698,689 to the University of Cincinnati to establish a baseline understanding of how toxins produced by cyanobacteria (blue-green algae) can be changed by exposure to ultraviolet (UV) light, a process used to disinfect drinking water. The research will be critical to developing cost-efficient UV technologies to treat water contaminated by such toxins. Dionysiou is also investigating treatment of algae-contaminated water specifically using sunlight and an environmentally friendly catalyst.

“Some of the cyanobacterial toxins are even more toxic than the venom produced by many poisonous snakes,” says Dionysiou, associate professor of environmental engineering. “These toxins have even been included in the list of chemical or biological warfare agents.” He explains that the toxins produced by cyanobacteria include hepatotoxins, neurotoxins and dermatotoxins, which affect the liver, nervous system and skin, respectively. Among the most commonly found cyanobacterial toxins is a group called microcystins. Microcystin-LR, for example, is a potent hepatotoxin.

The problem is not confined to the United States, where it is found in the Great Lakes region and Florida, for example. Cyanotoxins are also found in Northern European countries like Scandinavia, as well as France, the United Kingdom, Turkey, and Australia. Blue-green algae can grow in freshwater lakes, ponds and wetlands. They thrive in stagnant water under certain environmental conditions and eutrophication. Eutrophication refers to the “enriching” of a lake with nutrients such as phosphorous and nitrogen. This enrichment occurs frequently as a result of human activity, whether from domestic or industrial sewage, leaching of pesticides or draining of farm fertilizer runoff, as well other sources. For example, Lake Erie is a eutrophic lake that receives more than 65 billion gallons of domestic and industrial wastes each year, not even counting agricultural run-off. Some blue-green algae also produce their own food through photosynthesis.

Large growths of algae, known as harmful algal blooms, and their released toxins can be extremely toxic if swallowed by wildlife, livestock or people who drink untreated water. Because of such high toxicity, the World Health Organization assigned a provisional concentration limit of one microgram per litre of microcystin-LR and other cyanobacterial toxins in water. In January 2007, an EPA panel suggested lowering the provisional level to 100 nanograms per litre, or 100 parts per trillion.

While the problem associated with cyanobacterial toxins was known from early studies in 1870s in Australia, new developments of analytical methods helped determine the chemical structure of such toxins and identify new toxins. In addition, advances in instrumentation and chemical analysis helped detect such toxins in many other countries and at much smaller concentrations.