2016 Data Results:
Ryan Reece collects a water sample to be analyzed for microcystin, a common algal toxin.
During the summer of 2015, many citizen scientists with the Lakes of Missouri Volunteer Program began monitoring for the presence of the algal toxin, microcystin. By 2016, we expanded the program to collect more more than 4 times as many samples at more locations across the state of Missouri. By combining monitoring efforts of the Lakes of Missouri Volunteer Program and the University of Missouri's Statewide Lake Assessment, we collected 480 samples at 111 locations from May through September of 2016.
It is our hope that these data will help us to predict when and where toxins might occur in Missouri. Collecting the samples is a simple process, requiring minimal training and a sampling device, supplied by us. Algal toxin monitoring is done in addition to the standard monitoring of the Lakes of Missouri Volunteer Program.
Maximum concentration of the algal toxin microcystin observed at 111 lake sites across Missouri. Highest values were typically observed in the plains regions of norther and western Missouri.
What We Found
The map above shows the maximum microcystin value observed at each of 111 lake sites in Missouri during 2016. A small black dot means that all samples from that particular lake had low or undetectable concentrations of microcystin. Large red circles mean that at least one observation had a concentration greater than 4 micrograms per liter (parts per billion).
You may have noticed that lakes in the northern portion of the state are more likely to have high concentrations of the algal toxin than lakes to the south. We see a similar pattern in the distributions of phosphorus and algal biomass across the state. This distribution is largely related to the soils and topography (surface features) of the land in the regions.
The graph above shows, by month, the percent of samples with detectable microcystin concentrations (greater than 0.15 ug/L). Each bar color represents a year. From left, 2004, 2005, 2006, 2016.
Are Algal Toxins Increasing in Missouri?
We last measured microcystin at this statewide scale during 2004 to 2006, when Jennifer Graham (now at USGS) was working on her dissertation. Comparing the 2016 data to the 2004-2006 data shows that while the occurrence of microcystin in our lakes seems to have increased, the overall concentration of microcystin has not.
The graph above shows the percent of samples with detectable amounts of microcystin for each month during the summer sampling season (May through August) for 2004, 2005, 2006 and 2016. For the 2016 sampling season (green bars), the percent of samples with detectable microcystin levels was higher than any of the previous years. The percent of August 2016 samples with detectable toxin was fully 3 times higher than observed in 2004-2006!
Don't panic! Please look at the table below the graph that shows the mean concentration found each month. In August, for example, the 2016 average concentration is about 25% lower than that found from 2004-2006. The differences in mean observed microcystin concentration are even greater in other months. So, it would appear that even though we are finding microcystin in more lakes, the concentrations haven't increased.
We are just getting started with this work. More data will help us figure out if the amount of microcystin in Missouri lakes are changing, and, if so, where the changes are occurring.
What's New for 2017?
We have been measuring one algal toxin, microcystin, and beginning in 2017 we will be looking for another algal toxin, called cylindrospermopsin. This liver toxin was found in 5 of 36 Missouri lake samples in 2006. A 2007 EPA national lake survey found cylindrospermopsin in a few lakes in southeast Missouri. These surveys featured single samples, and did not monitor lakes over time. By inviting citizen scientists to participate in the process, we will collect more than 500 samples between April and September of 2017. This will provide Missouri's first broad-scale survey of this toxin.
Closeup of the distribution of cylindrospermopsin in Missouri in 2007. Each lake was sampled once. This season, we plan to measure cylindrospermopsin and microcystin from late April through mid-September.
This work is a combined effort from citizen scientists, the University of Missouri, the Missouri Department of Health and Senior Services, Missouri DNR, and the EPA. We will be keeping tabs on algal toxins in Missouri's lakes; hopefully we don't find anything!
New Guidance from EPA on Algal Toxins
In February 2017, the Environmental Protection Agency (EPA) released draft recreational criteria values for microcystin and cylindrospermopsin. The draft criteria values are lower than many states' existing recreational criteria and are based on exposure to the toxin while swimming. According to EPA, "because children spend more time in the water and ingest more water per body weight while recreating, EPA derived these recommended criteria based on children's recreational exposures."
The EPA draft criteria values are only recommendations, but they highlight the health concerns of algal toxins.
EPA's recently released draft criteria for two algal toxins, microcystin and cylindrospermopsin.
May 22, 2017