What, How, When, and Where: Spatiotemporal Water Quality Hazards of Cyanotoxins in Subtropical Eutrophic Reservoirs

Abstract

Though toxins produced during harmful blooms of cyanobacteria present diverse risks to public health and the environment, surface water quality surveillance of cyanobacterial toxins is inconsistent, spatiotemporally limited, and routinely relies on ELISA kits to estimate total microcystins (MCs) in surface waters. Here, we employed liquid chromatography tandem mass spectrometry to examine common cyanotoxins, including five microcystins, three anatoxins, nodularin, cylindrospermopsin, and saxitoxin in 20 subtropical reservoirs spatially distributed across a pronounced annual rainfall gradient. Probabilistic environmental hazard analyses identified whether water quality values for cyanotoxins were exceeded and if these exceedances varied spatiotemporally. MC-LR was the most common congener detected, but it was not consistently observed with other toxins, including MC-YR, which was detected at the highest concentrations during spring with many observations above the California human recreation guideline (800 ng/L). Cylindrospermopsin was also quantitated in 40% of eutrophic reservoirs; these detections did not exceed a US Environmental Protection Agency swimming/ advisory level (15,000 ng/L). Our observations have implications for routine water quality monitoring practices, which traditionally use ELISA kits to estimate MC levels and often limit collection of surface samples during summer months near reservoir impoundments, and further indicate that spatiotemporal surveillance efforts are necessary to understand cyanotoxins risks when harmful cyanobacteria blooms occur throughout the year.

A Visible-Light-Driven Self-Powered Nodularin-R Biosensing Platform Controlled by an Integrated Portable Photoelectrochemical Detection Device

“…Several analytical techniques have been developed for the detection of NOD-R, including enzyme-linked immunosorbent assays, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and fluorescence polarization immunoassays . However, these methods often involve excessive use of harmful reagents, expensive instrumentation, and require specialized operators, falling short of the requirements for on-site detection. − Recently, there has been increasing interest in the use of photoelectrochemical (PEC) techniques for monitoring water-related contaminants owing to their simplicity, rapidity, and high sensitivity. , Ouyang et al introduced a self-powered PEC sensor that relied on xenon lamp excitation and achieved highly sensitive microcystin-LR (MC-LR) detection by constructing Au/CeO 2 /g-C 3 N 4 heterostructures.…”