Blue-green algae, also known as cyanobacteria, are poorly monitored in the United States, according to experts.

Toxic algae have been found to be increasingly growing in US waters and could become a global threat with its unappreciated risk to the quality of recreational and drinking water.

Researchers from the Oregon State University and University of North Carolina analyzed the broad scope of the growing problem in cyanobacteria and published their findings in Current Environmental Health Reports.

The researchers at OSU emphasized that there is currently no mandated testing for cyanobacteria by the state federal regulators of drinking water. There is also no reporting required for outbreaks that have been associated with algal blooms. They also said that climactic change, altered use of land and the increasing toxicity of the bacteria could bring much attention to this growing issue in the future.

Currently, factors that contribute to the continuous algal blooms include rising temperatures and levels of carbon dioxide, rivers that have been dammed worldwide, wastewater nutrients and agricultural fertilizers. These factors can cause many problems along rivers, lakes and reservoirs, especially during the heat of summer.

This year, the West has experienced low snow pack and drought, leading to large toxic algal blooms that occurred earlier than they did in the past years. In the Willamette River near Portland, Oregon and Upper Klamath Lake and majority of the Klamath River, toxic blooms have occurred for two years in a row.

These toxic algal blooms not only posted a great health warning among humans, but have also caused poisoning in marine life. Throughout the West Coast, domoic acid shellfish poisoning caused shellfish harvests to close. This is the largest algal bloom ever recorded in history.

According to a national survey by the EPA in 2007, the liver toxin microcystin, which is also a potential liver carcinogen, was found in one in every three lakes tested. In the survey, cyanobacteria were also manifested in toxin strains that produce neurotoxins and those that cause gastrointestinal illnesses and acute skin rashes.

Although cases in humans are rare, the toxins are often fatal to animals that drink contaminated water. Last year, Toledo, Ohio temporarily cut down its supply of drinking water to avoid cyanobacterial contamination in Lake Erie.

"The biggest health concern with cyanobacteria in sources of drinking water is that there's very little regulatory oversight," said the postdoctoral scholar Tim Otten, of the Department of Microbiology at OSU and the study's lead author.

The research was supported by the National Science Foundation and the US Geological Survey.

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