by April Scheinoha
Water samples have validated the city of Thief River Falls’ decision to close the Bill LaFave Park beach to swimmers. The decision was made Friday due to the amount of goose dung and lack of rain in the area.
On Wednesday, the Red Lake Watershed District announced that all three water samples collected at the beach were over the Minnesota Pollution Control Agency’s acute standard for E. coli. Corey Hanson, RLWD water quality coordinator, noted the MPCA standard is 1,260 MPN/100ml and the chronic (monthly geometric mean) standard is 126 MPN/100ml.
“Concentrations greater than those numeric standards mean that the water is not safe for swimming, wading or other forms of recreation in which immersion and inadvertent ingestion of water is likely. To add more perspective on the severity of the E. coli problem, the maximum E. coli concentration that the lab can detect in a sample is 2,419.6 MPN/100ml. The sample collected at the west edge of the beach was right at that mark,” Hanson wrote in an email to Thief River Falls Water Systems Superintendent Wayne Johnson. Hanson shared the email with Thief River Falls news media.
The center of the beach area had a concentration of 1,413.6 MPN/100ml, and the east edge of the beach area had a concentration of 1,986.3 MPN/100ml. The overall geometric mean of the three samples was 1,894 MPN/100ml.
Hanson collected the samples Monday at an approximate depth of two feet (knee-deep). The samples were then sent to RMB Environmental Laboratories.
“There is a lot of merit to the idea that this is a localized problem that is coming from the geese. There definitely is ‘excessive goose waste’ at the beach. It’s not very likely that the problem is coming from the Red Lake River, upstream of the city. The August geometric mean for the Red Lake River near Thief River Falls is only 22.3 MPN/100ml,” Hanson wrote.
A test was also conducted for blue green algae, which earlier came back negative.