ANALYTICAL METHODS FOR THE ANALYSIS OF BLUE-GREEN ALGAL TOXINS -A REVIEW
Report No FR0272
H A James
To review the literature for methods used to analyse blue-green algal toxins in water, and to suggest potential methods for those toxins for which methods do not currently exist.
Little or no information exists on the levels of algal toxins in environmental or drinking waters, and it is consequently difficult to assess the scale of the threat posed by their potential presence. This paucity of data is mainly due to the lack of suitable analytical methods to detect and quantify the toxins in water. Prior to the development of such methods, it is necessary to review and evaluate relevant work that has been reported, so that future efforts are effectively directed.
III RESUME OF CONTENTS
Only toxins produced by freshwater blue-green algae have been considered. These may be conveniently divided into four groups - the microcystins, anatoxins, saxitoxins and lipopolysaccharides. The information relevant to the analysis of each of these groups in water has been reviewed and discussed.
The great majority of reported methods refer to the analysis of anatoxin-a in water, and it should not be difficult to develop a validated quantitative method for this toxin.
There is only one method which provides reasonable quantitative data for one of the microcystins. This was developed specifically for microcystin-LR. Additional effort is required to either extend this method to other microcystins, or to develop alternative methods. Although immunoassay-based methods have been reported for microcystins, they have yet to be widely applied and there have been no comparisons of their performance with chemically-based methods.
Methods exist for the analysis and detection of saxitoxins. These relate to their presence in shellfish, and there is a need to investigate suitable extraction methods for their analysis in water.
Lipopolysaccharides are not yet fully characterised, and method development will be difficult until their structures are clarified. Insufficient toxicological data currently exists to allow justifiable detection limits for any of the algal toxins in water to be set.
As a considerable body of information relating to the analysis of anatoxin-a in water exists, a quantitative method for this toxin should be developed.
Further work (either on chemically- or immunoassay-based methods) is required to develop methods for a range of microcystins. Pure standards for the majority of these are not currently commercially available; there is therefore a requirement for the production of appropriate amounts by isolation from algal cultures. If analysis is required for the saxitoxin group of toxins in freshwaters, effective methods for their extraction from water need to be developed. It would be prudent to establish which of these toxins are produced by freshwater blue-green algae prior to undertaking work in this area.
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