The U.S. Environmental Protection Agency (EPA) issued the first nationwide guidelines and recommendations in May 6, 2015 to help local officials and managers of water utilities on identifying unsafe levels of algal toxins in public water systems based on the best available science.
EPA officials announced the recommended thresholds that should trigger timely actions from state officials and water plant operators like quickly reducing levels of the two common algal toxins, issuing health advisories or distributing do-not-drink warnings. Two sets of threshold points were created, one for young children and another recommendation for the rest of the American population.
Around 48 million Americans consume drinking water from reservoirs and lakes that could possibly be contaminated with toxins produced by algae-like bacteria, according to EPA. Pollution from blue-green algae, cyanobacteria, in Lake Erie left more than 400,000 citizens from southeastern Michigan and northwestern Ohio with unhealthy tap water for 48 hours last August 2014.
Climate change and advanced levels of nutrients such as phosphorus could be the possible causes of increasing cases of algal pollution, according to scientists.
The guidelines should apply on two common toxins, cylindrospermopsin and microcystin, created by cyanobacteria. They could seriously cause diarrhea, vomiting and human poisoning, and have exterminated livestock animals. Extended exposure can harm the kidneys and liver.
The EPA's recommended thresholds for kids younger than school age were 0.7 parts per billion for cylindrospermopsin and 0.3 parts per billion for microcystin. For the rest of the population, the limits were 3 parts per billion for cylindrospermopsin and 1.6 parts per billion for microcystin.
Some states, including Florida, Minnesota, Ohio, Oklahoma and Oregon, have their own criteria, 1 part per billion limit as per recommendation by the World Health Organization in 1998 and currently used by more than a dozen countries. The EPA figures reflect more up-to-date science, according to Peter Grevatt, EPA's top regulator for drinking water and groundwater.
When the levels of the algal toxins go beyond the standards, water plant operators should balance the treating of water through techniques such as increasing chlorine inputs without surpassing prescribed disinfection perimeters, which could present some operating challenges.
The American Water Works Association (AWWA), whose 50,000 affiliates generate 80 percent of the country's supply of drinking water, requests more solid actions to reduce phosphorus and other nutrients that could be sources of algae contamination cases, according to J. Alan Roberson, AWWA director of federal relations.
"That will make it easier for people to be confident in the quality of their tap water," Roberson said.
Photo: David Simmonds | Flickr