Bioaccumulation of methylisoborneol and geosmin on some freshwater organisms

We investigated the bioaccumulation of 2-methylisoborneol (MIB) and geosmin (GEO) during cyanobacterial bloom episodes at Billings Reservoir in São Paulo city for a period of two years (covering all seasons in between 2017 and 2018). Cyanobacterial VOCs were monitored by a GC-MS method based on solid phase microextraction (SPME) and headspace (HS), and samples of water, cyanobacteria, copepods and fish (tilapia) were monitored. Three different methodologies to identify and quantify VOCs were tested, and the results suggested that HS-SPME-GC-MS was the most efficient among them. The highest levels of GEO and MIB were detected in fish tissue during the summer, coinciding with the higher temperatures and lower water levels in the reservoir, which lead to a more predominant growth of cyanobacteria. The presence of MIB and GEO increased higher up the food chain (water < cyanobacteria < copepods < fish). These results indicate that MIB and GEO can bioaccumulate and biomagnify in the environment and might be a concern for public health because water taste and odor can be affected as well as species used in aquaculture.