Date of Award

Fall 12-2019

Semester of Degree

December

Document Type

Open Access Thesis

Degree Name

Ph.D. in Chemistry

Department

Chemistry

Major Professor

Gregory Boyer

Steering Committee Member

John Hasset

Steering Committee Member

Dave Kieber

Abstract

Cyanobacterial blooms occur worldwide and produce a range of harmful compounds. While most attention had focused on the hepatoxic microcystins, other cyanobacterial toxins such as the neurotoxic paralytic shellfish poisoning toxins (PSTs) and anatoxins (ATXs) may threaten environmental health.

Anatoxins (ATXs) are potent nicotinic agonists that can cause death within minutes. While the distribution of anatoxin-a has been evaluated in lakes, two derivatives, homo- anatoxin and dihydro-anatoxin, have not been evaluated.

Paralytic shellfish poisoning toxins (PSTs) are lethal neurotoxins with more than 60 known variants. While originally identified in marine systems, PSTs are frequently detected in freshwaters. The distribution of PSTs in freshwater systems have not been evaluated. We include the anatoxins and PSTs in the first survey of New York lakes for neurotoxins.

The occurrence of ATXs and PSTs were determined in more than 1,000 blooms sampled across 245 New York lakes. While less prevalent than the microcystins, these neurotoxins were found in ~15% of blooms surveyed. The PSTs occurred at concentrations well above drinking water and recreational guidelines for the toxins, while anatoxins concentrations were below recreational guidelines but above drinking water guidelines.

Two New York lakes were examined in more detail for the presence of toxins. Butterfield Lake primarily contained PSTs produced by benthic Microseira wollei. These cyanobacteria were found at two sites, where the toxins were unlikely to pose a significant health risk to lake users as PSTs were not detected in open waters. Concern focused on humans or animals being exposed to dislodged benthic material.

Chautauqua Lake experienced numerous planktonic blooms that contained a complex mixture of toxins. The microcystins and PSTs were detected in high concentration, while anatoxin-a concentrations were low. Potential for exposure, and the variability in bloom size and toxin composition, suggests potential recreational human health risks.

This work emphasizes that neurotoxins present a significant health concern within New York State, and that monitoring programs for cyanobacteria toxins should not focus solely on the microcystins to assess human health risk from cyanotoxins. The xxix potential for exposure to these toxins varies between lakes, and monitoring strategies may need to be adapted to different locations.

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