This data release contains cyanotoxin, chlorophyll-a, and pheophytin-a concentration, cyanobacterial genetics, phytoplankton community composition, and multiparameter sonde data collected from 20 sites in five northeastern United States river basins (Penobscot (ME), Santuit (MA), York (VA-WV), Salem (NJ), and Peconic (NY)). Solid Phase Adsorption Toxin Tracking (SPATT) passive samplers were deployed at all sites between August 31 and September 2, 2020, and retrieved after 7 days. Discrete water samples were collected when SPATTs were deployed, and at 2 sites (USGS station IDs 01670257, 0167014792), samples were also collected when the SPATTs were recovered. Sonde data were collected when deploying and retrieving the SPATTs. The SPATT samples were extracted and analyzed for cyanotoxins (anatoxin-a, cylindrospermopsin, microcystin, saxitoxin) by enzyme-linked immunosorbent assay (ELISA) and liquid chromatography tandem mass spectrometry (LC/MS/MS). Sonde data included measurements of water temperature, pH, specific conductance, dissolved oxygen, turbidity, chlorophyll, phycocyanin, and phycoerythrin fluorescence (in relative fluorescence units and micrograms per liter), and nitrate, however some sensors were not available at all locations. Discrete samples were analyzed for total cyanotoxin concentration (anatoxin-a, cylindrospermopsin, microcystin, saxitoxin) by ELISA and LC/MS/MS, chlorophyll-a, pheophytin-a, cyanotoxin synthetase genes, and phytoplankton community composition. Saxitoxin could not being analyzed by LC/MS/MS so an additional ELISA analysis was performed instead.

This data release contains cyanotoxin concentrations for microcystins, cylindrospermopsins, anatoxins, and saxitoxins assessed using Enzyme-Linked Immunosorbent Assays (ELISA) on 363 samples collected from 82 surface-water sites located in the Cascade Range in Oregon, and eight sites located outside of the Oregon Cascade Range in Washington and California, during 2016-2020. Three sample types were assessed: 1) benthic colonies and mats of cyanobacteria (n=109), 2) plankton net tows (n=90), and 3) Solid Phase Adsorption Toxin Tracking samplers (SPATTs)(n=164).

This data release contains cyanotoxin concentrations for microcystins, cylindrospermopsins, anatoxins, and saxitoxins assessed using Enzyme-Linked Immunosorbent Assays (ELISA) on 363 samples collected from 82 surface-water sites located in the Cascade Range in Oregon, and eight sites located outside of the Oregon Cascade Range in Washington and California, during 2016-2020. Three sample types were assessed: 1) benthic colonies and mats of cyanobacteria (n=109), 2) plankton net tows (n=90), and 3) Solid Phase Adsorption Toxin Tracking samplers (SPATTs)(n=164).