Methods to detect cyanobacteria and their toxins in the environment

Cyanobacteria blooms are since early times a cause for environmental concern because of their negative impact through the release of odors, water discoloration, and more dangerously through the release of toxic compounds (i.e. the cyanotoxins) that can affect both human and animal welfare. Surveillance of the aquatic ecosystems is therefore obligatory, and methods to achieve such require a prompt answer not only regarding the species that are producing the blooms but also the cyanotoxins that are being produced and/or released. Moreover, besides this well-known source of possible intoxication, it has been demonstrated the existence of several other potential routes of exposure, either for humans or other biota such as through food additives and in terrestrial environments (in plants, lichens, biological soil crusts) and the recognition of their harmful impact on less studied ecosystems (e.g. coral reefs). Nowadays, the most frequent approaches to detect toxic cyanobacteria and/or their toxins are the chemical-, biochemical-, and molecular-based methods. Above their particular characteristics and possible applications, they all bring to the environmental monitoring several aspects that are needed to be discussed and scrutinized. The end outcome of this review will be to provide newer insights and recommendations regarding the methods needed to apply in an environmental risk assessment program. Therefore, a current state of the knowledge concerning the three methodological approaches will be presented, while highlighting positive and negative aspects of each of those methods within the purpose of monitoring or studying cyanobacteria and their toxins in the environment.