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Algal toxins and human health: A brief overview and notes on needed research directions
Citation:
Chernoff, N. Algal toxins and human health: A brief overview and notes on needed research directions. Presented at Society of Toxicology and Chemistry (SETAC) Annual Meeting, November 11 - 15, 2012.
Impact/Purpose:
This will be presented at the Society of Environmental Toxicology and Chemistry (SETAC) Annual Meeting, November 11-15, 2012, Long beach, CA
Description:
Marine and freshwater algae, both algae and cyanobacteria, are known to produce a wide variety of toxins that have caused severe adverse health effects in humans and other vertebrate species. There is general agreement that there is currently an increase in the incidence of hazardous algal blooms (HABs), the periods of occurrence, and their geographical range. The primary reasons for these changes include eutrophication of water bodies, climate change, global spread of individual species, and their intrinsic adaptability. Some toxins are known to be produced by only a small number of organisms while others (e.g. cylindrospermopsin (CYN) and saxitoxin) are generated by multiple species in evolutionarily distant groups. The toxins in HABs may induce general effects (CYN) or may target specific organ systems like the liver (microcystins) or the central nervous system (anatoxin-a, saxitoxin). Poisoning episodes involving severe toxicity and/or lethality have been recorded in humans after exposure to the above toxins as well as many others. Laboratory animal models have been developed for many of the toxins and there is excellent agreement in the types of toxicity observed across mammalian species. Lower vertebrates and invertebrates, however, often show different spectrums of toxicity and may display significant bioaccumulation of toxins. Many fundamental areas of research require additional work. The toxicity of mixtures is a critical data gap because exposures to single toxins rarely, if ever, occur. Reasons for this include the fact that during blooms, other species producing different toxins may be present; many species produce more than one toxin during a bloom; and blooms often occur sequentially in terms of the predominant species, and exposure to liver toxins may, for example, be followed by neurotoxin exposure. Additional underemphasized research areas include mechanism studies, and both developmental toxicology and long-term exposure studies (including carcino