Harmful algae blooms are increasing in lakes and rivers nationwide.

And they’re going largely unreported, according to a new report from the Environmental Working Group, a nonprofit that researches toxic chemicals and drinking water pollutants.

Algal blooms occur naturally with a combination of sunlight, warm weather, low-turbidity water and the presence of nutrients that phytoplankton thrive on – such as nitrogen or phosphorous. With significant nutrient levels, this can ultimately deplete oxygen levels in a process called eutrophication and affect aquatic life.

Agricultural runoff, stormwater runoff, wastewater, fossil fuel use, fertilizers, detergents and pet waste contribute to nutrient pollution, according to the Environmental Protection Agency.

“It has a lot to do with nonpoint source pollution runoff,” said Matt Powell, Bowling Green’s environmental manager.

This can lead to “harmful algal blooms,” which occur after the rapid reproduction of blue-green algae. This algae, called cyanobacteria, produces toxins called microcystins, which can pose health risks to people, pets and wildlife.

Since 2010, the EPA reported one harmful algae bloom in the Nolin Lake during a national lake assessment, according to EWG.

But there have been many other algal blooms in the past decade, including one “harmful algal bloom” identified by the Army Corps of Engineers at the Barren River Lake in 2014.

“It’s hard to know how many are happening out there,” said Ward Wilson, the executive director of the Kentucky Waterways Alliance, but “I do think there are a lot of unreported algal issues.”

Earlier this year, there was a green algal bloom in puddles near a trash fire at the Scott Waste Services transfer station in Auburn – though it wasn’t reported by the state to be a “harmful algal bloom.”

There have been zero algal blooms reported to the Kentucky Energy and Environment Cabinet in 2019, according to spokesman John Mura.

In Warren County, Bowling Green Municipal Utilities and the Warren County Water District extract water from the Barren River. BGMU, which provides water to WCWD, treats this water for all federally and state-mandated pollutants.

The Kentucky Division of Water regulates public water systems, which provide about 95 percent of state residents with drinking water. Public water runs through a process of chlorination, filtering and disinfection to eliminate bacteria and contaminants.

But there are no federal regulations for microcystins and other cyanotoxins in drinking water, according to EWG.

In addition to EWG’s recent report, there have been efforts to call attention to algal blooms.

The Kentucky Energy and Environment Cabinet and Watershed Watch in Kentucky partnered up a few years ago to launch an annual lake monitoring program to assist the state with monitoring Kentucky’s 440,000 acres of lake waters, which includes documenting algal blooms.

People can also report algae blooms to BloomWatch, an app where people can submit photos of algae blooms for public viewing.

For more information, visit cyanos.org/bloomwatch.