This new paper might fall under the category of “things you don’t want to think about.” After reading this study by Buse et al., I now ponder what’s in my drinking water every time I fill up a glass from the tap:
Buse HY, Lu J, Struewing IT, Ashbolt NJ. (2013) Eukaryotic diversity in premise drinking water using 18S rDNA sequencing: implications for health risks. Environmental Science and Pollution Research, doi:10.1007/s11356-013-1646-5
From the abstract:
…18S rRNA gene sequences from 24 hot (36.9—39.0 °C) and cold (6.8—29.1 °C) drinking water samples were analyzed and classified into major eukaryotic groups. Each major group, consisting of free-living amoebae (FLA)/protozoa, algae, copepods, dinoflagellates, fungi, nematodes, and unique uncultured eukaryotic sequences, showed limited diversity dominated by a few distinct populations, which may be characteristic of oligotrophic environments. Changes in the relative abundance of predators such as nematodes, copepods, and FLA appear to be related to temperature and seasonal changes in water quality.
The paper emphasized the methods cannot detect whether 18S sequences represent living organisms, fragmented cells, or extracellular DNA, but nonetheless the results are very interesting. There’s also a good discussion of potential human health risks, since microeukaryotes in drinking water could harbor bacterial and viral pathogens. Definitely a good read!