Measurement of Algal Toxins in the Environment

Abstract

Algal toxins are important from an analytical point of view because they need to be constantly scrutinized owing to the danger they pose to consumers when they concentrate in filter‐feeding shellfish or in drinking water and fish. Their chemical diversity is very large, with each group having many analogs. Each group has different pharmacological activities, although not all the mechanisms of action are understood. The main marine toxin groups are as follows: saxitoxin and analogs, okadaic acid and dinophysistoxins, azaspiracids, yessotoxins, pectenotoxins, cyclic imines, domoic acid, ciguatoxins, brevetoxins, palytoxin, gambierol, and polycavernoside. The main cyanobacterial toxins considered are hepatotoxins such as microcystins, nodularin, and cylindrospermopsin. The research concerning marine toxins is underdeveloped owing to a historic scarcity of standards. This has delayed not only the progress in their pharmacology but also the development of methods for detection and measurement. In the current situation, the mouse bioassay is the most common method being used to measure them. New methods are rapidly emerging as future solutions: (i) functional and nonanalytical methods, which provide information on their toxicity and quantify the toxin group (cell assays, receptor assays, biosensor assays), (ii) biochemical methods that do not provide information on toxicity (antibody‐based methods), and (iii) analytical methods, which identify the species in each toxin group, and can quantify those for which standards are available. The main drawback of these methods is the lack of toxicity equivalent factors, which allow the conversion of toxin amounts to toxic values of a reference toxin. None of these methods has been validated, and therefore much remains to be done in the field.

Influence of Different Shellfish Matrices on the Separation of PSP Toxins Using a Postcolumn Oxidation Liquid Chromatography Method

“…The highly toxic and unpredictable nature of these biotoxin blooms means that the toxin content of shellfish in affected areas is monitored [ 2 ]. PSP monitoring programs rely on relatively intensive sampling and analysis protocols that require rapid, sensitive, accurate, and precise analytical techniques for the analysis of PSP toxins [ 3 ].…”

Ecological assessments with algae: a review and synthesis

“…Toxin analysis is challenged by the lack of analytical standards and toxicity equivalence factors (Botana et al. ). The World Health Organization established a provisional guideline of 1 μg · L −1 for microcystin‐LR, a common cyanotoxin, but not for other algal toxins.…”

Use of Algae in Ecological Assessments

“…Algal toxins can be measured by high performance liquid chromatography (HPLC), gas and liquid chromatography methods coupled with mass spectrometry (GC/MS or LC/MS), and enzyme-linked immunosorbent assays (ELISA). Analysis of toxins is challenging because of the lack of analytical standards, and assessment of toxins is limited because of a lack of toxicity equivalence factors (Botana et al, 2009), which indicate when toxins are too high. Presence of toxin-producing algae is an indicator of a threat to EGS, but toxin-producing algae often do not produce the toxins.…”