Evidence for Unusual Paralytic Shellfish Poisoning Toxin-like Compounds in Cayuga Lake, New York
Start Date
23-5-2022 5:45 PM
End Date
23-5-2022 7:00 PM
Abstract
Cayuga Lake (part of the finger lakes in central New York (NY), USA provides drinking water for several cities and is surrounded by a community of approximately 120,000. Cyanobacterial blooms were identified widespread throughout the lake and targeted samples were collected by citizen scientists in July-August (summer) and later in September-October (fall) in 2017 and 2018. Samples (n = 30) in Summer were dominated by Dolichospermum, while Microcystis dominated in the fall. In periods of Dolichospermum dominance paralytic shellfish poisoning toxins (PSTs) were identified by HPLC post-column chemical oxidation (PCOX), with concentrations ranging from ~25-50 µg/L. While PSTs were identified from fluorescent interferents through the oxidation of the central PST ring, the structures of the PSTs were unclear as retention times did not match those of reference materials. To confirm that these were PSTs, a subset of four samples were analyzed by the receptor binding assay (RBA), saxitoxin ELISA, and LC-MS/MS. PSTs were identified by each method. Higher concentrations of toxin were identified by ELISA than PCOX, which was unexpected as generally PSTs other than saxitoxin have poor cross-reactivity. Only saxitoxin was detected by LC-MS/MS at ~1 µg/L. While some PSTs are non-toxic, some of the PSTs appear to be active against RBA receptors, with one sample at concentrations in excess ~80 µg/L. PST profiles in freshwater environments are poorly understood. As PSTs have a range of toxicities, profile information is critical to better understand health risks. PSTs are likely present in Cayuga Lake, but the structures were unclear.
Evidence for Unusual Paralytic Shellfish Poisoning Toxin-like Compounds in Cayuga Lake, New York
Cayuga Lake (part of the finger lakes in central New York (NY), USA provides drinking water for several cities and is surrounded by a community of approximately 120,000. Cyanobacterial blooms were identified widespread throughout the lake and targeted samples were collected by citizen scientists in July-August (summer) and later in September-October (fall) in 2017 and 2018. Samples (n = 30) in Summer were dominated by Dolichospermum, while Microcystis dominated in the fall. In periods of Dolichospermum dominance paralytic shellfish poisoning toxins (PSTs) were identified by HPLC post-column chemical oxidation (PCOX), with concentrations ranging from ~25-50 µg/L. While PSTs were identified from fluorescent interferents through the oxidation of the central PST ring, the structures of the PSTs were unclear as retention times did not match those of reference materials. To confirm that these were PSTs, a subset of four samples were analyzed by the receptor binding assay (RBA), saxitoxin ELISA, and LC-MS/MS. PSTs were identified by each method. Higher concentrations of toxin were identified by ELISA than PCOX, which was unexpected as generally PSTs other than saxitoxin have poor cross-reactivity. Only saxitoxin was detected by LC-MS/MS at ~1 µg/L. While some PSTs are non-toxic, some of the PSTs appear to be active against RBA receptors, with one sample at concentrations in excess ~80 µg/L. PST profiles in freshwater environments are poorly understood. As PSTs have a range of toxicities, profile information is critical to better understand health risks. PSTs are likely present in Cayuga Lake, but the structures were unclear.