Tracing cyanobacterial blooms to assess the impact of wastewaters discharges on coastal areas and lakes

Abstract

The rapid detection of cyanobacterial blooms has become an emerging and urgent need during the last years due to the increasing number of cyanobacterial harmful blooms (CHABs) all over the world. The main responsibility of this phenomenon is attributable to the nutrient enrichment, resulting from eutrophication processes of anthropogenic origin. The blooms deplete oxygen in surface waters through excessive bacterial respiration and decomposition and often release toxic substances (cyanotoxins) causing fish mortality and risks for public health. We have initiated a worldwide program for the early detection of cyanobacterial blooms using combined techniques based on chemical/biochemical analyses of samples collected on specific sites identified with remote/proximal sensing tools. Here we report our results obtained from the analysis of cyanobacterial blooms using a new powerful approach based on the combined use of LCMS/MS (Liquid Chromatography Tandem Mass Spectrometry) and Molecular Networking to detect the presence of known and novel cyanotoxins. In addition, we report the most recent results from our case studies on specific coastal areas and lakes, where the presence of cyanobacteria was confirmed to be related to the excess nutrient input of anthropogenic origin, resulting from wastewater discharges or runoff from fertilisers and manure spread on agricultural areas. The monitoring of bloom occurrence, composition, frequency and chemistry can provide important indicators of degraded water quality, supporting the Government Bodies in the evaluation of effectiveness of wastewater plans that insist on a specific coastal area.