Occurrence of the cyanobacterial neurotoxin, anatoxin-a, in New York State waters

Cyanobacterial blooms are a serious environmental and health problem throughout the world. In New York State, cyanobacterial toxins such as the hepatotoxic microcystins and the neurotoxic anatoxin-a have been detected in various lakes including the lower Great Lakes. Compared to microcystins, the occurrence and distribution of anatoxin-a in New York State is poorly studied. This study provided the first systematic monitoring for anatoxin-a in New York State waters.;Anatoxin-a is a bicyclic alkaloid (MW 165) which has potent nicotinic agonistic activity and has caused several animal fatalities around the world and in New York State. It may be produced by several genera of cyanobacteria including Anabaena, Aphanizomenon, Planktothrix and Microcystis. Anatoxin-a is mainly retained within cells but can be released into the surrounding water column during cell senescence and lysis. To better understand its behavior in natural waters, the stability of anatoxin-a was examined under natural and artificial light and different pH conditions. Under the influence of light and/or pH, anatoxin-a readily degraded with a first order or a pseudo-first order kinetics. Anatoxin-a has a half-life of 4-10 hours under natural and artificial solar radiation, and several days up to several months in the absence of light. Several degradation products were formed during photolysis of anatoxin-a. The primary degradation product of anatoxin-a under artificial light was identified by NMR as tricycloanatoxin-a and the degradation was proposed to proceed via an intramolecular rearrangement process.;In New York State, anatoxin-a was periodically detected at concentrations above an cautionary level of 0.1 mug L-1 in the western basin of Lake Erie, the embayments along the southern shoreline of Lake Ontario, nearshore sites on Lake Champlain, and in other smaller inland lakes such as Onondaga Lake, Lake Neatahwanta and Lake Agawam. Anatoxin-a exceeded 1 mug L-1 in Lake Ontario, Lake Champlain, Onondaga Lake and Lake Agawam. In these lakes, the locations where anatoxin-a was observed are primarily shallower waters and are used extensively for recreational purposes. Exposure of humans or pets to cyanobacterial blooms in these areas during summer and fall is possible. The detection of anatoxin-a in waters in proximity to human habitats at concentrations higher than the cautionary level indicates the health risk associated with anatoxin-a is real.