Occurrence of harmful algal blooms (HABs) have been increasing in magnitude, frequency and duration due to anthropogenic factors such as eutrophication and climate change. These HAB events can present important risks to ecosystems and human health through release of toxins generated by some algae and cyanobacteria. Here, we examined the occurrence profiles of nine common cyanotoxins across twenty separate reservoirs in Texas, USA, because surface water quality information for cyanotoxins were not available for most potable source waters in the State. These twenty lakes were selected for study because the systems are located across a pronounced annual rainfall gradient within the State of Texas and were specifically sampled across multiple seasons and depth profiles. Multiple detections of both hepato- and neurotoxic substances were observed, including various microcystins and cylindrospermopsin, using previously reported methods using liquid chromatography tandem mass spectrometry. We identified cyanotoxins in both surface and bottom water samples, indicating that these contaminants of emerging concern may be present throughout the water column among seasons rather than only occurring at surface depth where routine surface water quality monitoring occurs during summer months. We then developed environmental exposure distributions to examine probabilities of encountering specific toxins relative to common cyanotoxins water quality guideline values. Because many local communities rely on these lakes for drinking water and other uses, observations of these HAB toxins indicates the need to implement routine surface water quality assessment efforts in inland waters.

Spatiotemporal occurrence and water quality hazards of common cyanobacterial toxins in reservoirs located across a pronounced annual rainfall gradient

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.