DWR investigation finds no algal toxins at Falls Lake

An investigation into a potential harmful algal bloom on Falls Lake turned up two types of bacteria present in samples, but did not detect toxins.
 
North Carolina Department of Environmental Quality’s Division of Water Resources staff collected samples to the east of Bayleaf Church Road on Dec. 7, after it was reported that a dog died from exposure to the water. The two types bacteria found in samples were Pseudanabaena and Cylindrospermopsis, both of which can potentially produce toxins, but further tests did not detect the presence of the algal toxin mycrocystin. 
 
DEQ’s Division of Water Resources monitors and samples three sites in Falls Lake monthly and twice per month in the summer, which includes analysis for phytoplankton (algae). There were no visual indications that an algal bloom was occurring in Falls Lake during routine monitoring on Nov. 18, according to DEQ. Final results of the analysis should be completed this week. DWR is continuing to investigate the matter, with staff sampling that portion of Falls Lake today (Tuesday) for toxins and algae.
 
North Carolina Department of Health and Human Services recommends humans and their pets avoid contact with water (including swimming and fishing) if a potential algal bloom is present.
 
This post has been updated to reflect DWR’s findings.