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Musty tastes in water - are the culprit compounds genotoxic?

Researchers in Brazil (from both ULBRA and UFRGS) have been investigating compounds which can cause undesirable effects in water, such as earthy-musty tastes and odours.  Cyanobacterial compounds can cause these tastes and odours in water.  However, the researchers describe the limited number of studies on the biological effects on human health of these cyanobacterial compounds, such as 2-methylisoborneol (2-MIB) and geosmin (GEO).  

In this investigation, the scientists assessed the cytotoxic and genotoxic potentials of 2-MIB and GEO using the MTT assay, the in vitro comet and cytokinesis-block micronucleus (CBMN-Cyt) assays on human HepG2 cells.

The researchers also investigated gene expression.  The toxicogenomics of genes responsive to DNA damage and metabolisation by the exposure of cells to 2-MIB and GEO were investigated.

During the comet assay, the stained nucleoids were immediately evaluated at 400 × magnification under an Olympus fluorescence microscope (excitation filter, 515–560 nm; barrier filter, 590 nm), equipped with an image analysis system (Comet Assay IV, Perceptive Instruments, UK).  For full experimental details of the comet assay and the other assays in this investigation, please refer to the original publication.

The results showed that concentrations of 2-MIB and GEO above 100 and 75 μg/mL, respectively, were cytotoxic to HepG2 cells.  Doses of 2-MIB (12.5, 25, 50, 75 and 100 μg/mL) and GEO (12.5, 25, 50, and 75 μg/mL) were unable to induce DNA damage, or events associated with chromosomal instability.

The scientists also reported that similarly, no concentration of each compound induced increments in gene expression of the DNA damage responsive genes. Although cytotoxicity was observed, concentrations that caused it are much higher than those expected to occur in aquatic environments.

The scientists concluded that environmentally relevant concentrations of both compounds, 2-MIB and GEO, are not expected to exhibit cytotoxicity or genotoxicity to humans.

Read the full story here:
Agents of earthy-musty taste and odor in water: Evaluation of cytotoxicity, genotoxicity and toxicogenomics.
Burgos L, Lehmann M, Simon D, de Andrade HH, de Abreu BR, Nabinger DD, Grivicich I, Juliano VB, Dihl RR.
Sci Total Environ. 2014 May 30;490C:679-685.