Measuring Algal Toxins in Missouri
In August of 2014, toxic blue-green algae in Lake Erie caused the city of Toledo to issue drinking water warnings, forcing residents to rely on bottled water. A month later, Carroll Township, Ohio, shut down their drinking water facility for a weekend because of high toxin levels. Additional treatment removed the toxin, but the systems had to be flushed to clear the pipes of contaminated water. Algal toxins are currently on the Environmental Protection Agency's Candidate Contaminants List, meaning allowable concentrations may someday be regulated at the national level. While some water treatment facilities monitor algal toxins, doing so is not yet mandatory.
Blue-green algae occur statewide. Not all species are capable of producing toxins, and the species capable of producing toxins do not do so at all times. The presence of toxins is most common in lakes with high nutrient concentrations. In Missouri, those lakes are generally in the Glacial Plains region north of the Missouri River or in the Osage Plains region along the western border. The map below shows microcystin (a common blue-green algae toxin) in Missouri during the summers of 2004 through 2006. The toxin was detected in 58% of the reservoirs monitored, though usually at low concentrations.
In 2015, citizen scientists with the Lakes of Missouri Volunteer Program will begin monitoring microcystin in Missouri lakes. Volunteers at lakes where blue-green algae blooms are likely or have historically occurred will be outfitted with special equipment for collecting and preserving samples. Because the analysis is expensive, volunteers will only sample when a bloom is occurring or is suspected of occurring. Some samples from 2014 will allow us to fine-tune our protocols before we implement monitoring statewide.
Some blue-green algae blooms occur as surface scums, while others are distributed throughout the water column. Sampling at the surface may over-represent a surface scum, while sampling below the surface may under-represent the surface scum. Our current prototype monitoring device is a PVC tube with a valve at one end. The design was intended to standardize the sampling depth while ensuring that a surface scum, if present, was included in the sample.
If you would like to participate in the LMVP and the toxic algae monitoring program, contact us.