Original paper

Co-occurrence of microcystin- and geosmin-producing cyanobacteria in the Tri An Reservoir, a drinking-water supply in Vietnam

Pham, Thanh-Luu; Tran, Thi Hoang Yen; Hoang, Nghia Son; Ngo, Xuan Quang; Tran, Thai Thanh

Fundamental and Applied Limnology Volume 193 Nr. 4 (2020), p. 299 - 311

41 references

published: Jun 29, 2020
published online: May 7, 2020
manuscript accepted: Mar 23, 2020
manuscript revision received: Mar 16, 2020
manuscript revision requested: Jan 7, 2020
manuscript received: Dec 25, 2019

DOI: 10.1127/fal/2020/1296

BibTeX file

ArtNo. ESP141019304001, Price: 29.00 €

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Abstract

The present study aimed to investigate the occurrence and distribution of microcystin-(MC) and geosmin-producing cyanobacteria in the Tri An Reservoir, a drinking-water supply in Southern Vietnam. The MC concentration was measured using high-performance liquid chromatography (HPLC). Geosmin production was screened using headspace solid-phase microextraction (HPME) and gas chromatography/mass spectrometry (GC/MS). The ability of cyanobacteria to produce MC and geosmin was determined by the presence of two molecular markers: mcyA and geoA, respectively. A maximum MC concentration of 207.6 ± 14.2 µg g–1 dry weight (DW) was detected from an isolated Microcystis aeruginosa (Kützing) (strains TAMA1), and the maximum geosmin concentration of 114.2 ± 6.1 ng g–1 wet weight (WW) was detected from an isolated Dolichospermum circinale (Rabenhorst) (strains TADC4); MC and geosmin were also observed in water-bloom samples, with the highest concentrations being 463.6 ± 34.7 µg g–1 DW and 148.5 ± 9.8 ng g–1 WW, respectively. These results represent the first molecular evidence of the co-occurrence of MC- and geosmin-producing cyanobacteria in a drinking-water-supply reservoir in Vietnam. Given the success of the molecular techniques and chemical analysis used, we propose that multiplex polymerase chain reaction assays, HPLC, and HPME GC/MS can be reliable tools for investigating MC and geosmin in water-bloom and cyanobacterial samples. Further, we propose that they can be used to create early-warning systems for harmful secondary metabolites produced by cyanobacteria in drinking-water supplies.

Keywords

taste and odor • off-flavor compound • earthy/muddy smell • cyanotoxin