| The intense use of ground water in the Vietnamese Mekong delta is causing a proceeding land subsidence and salinization of ground water sources. Surface water could serve as an alternative drinking water source, but has a higher risk of contaminations with health related micro-organisms. As part of the joint German Vietnamese project ViWat: Engineering, approx. 150 surface, ground and drinking water samples were sampled from the Mekong area in cooperation with the National Center for Water Resources Planning and Investigation in Vietnam (NAWAPI), and screened for bacterial and viral fecal indicators and pathogens (e.g. E. coli, coliforms, enterococci, RNA/DNA-phages). Positive coliform samples were identified with MALDI-TOF-MS and sequencing. For selected samples, antibiotic resistance genes were quantified with quantitative PCR (qPCR).<br>
In all drinking water samples, E. coli, coliforms and enterococci bacteria as well as phages were below the detection limit. In contrast, most surface water samples were contaminated with fecal indicator bacteria and phages. From 88 ground water samples, mostly taken from private household areas, 23 were positive for coliform bacteria. 2 samples were positive for E. coli, enterococci and phages (2/88). By MALDI-TOF-MS and sequencing techniques, V. cholera and V. vulnificus bacteria were identified as well as classic Coliforms such as Enterobacter, Klebsiella and Citrobacter. First results also indicated the presence of antibiotic resistance genes (e.g. Sul1).<br>
According to the results of the fist sampling campaign, some ground water wells showed an influence of the highly contaminated surface water. For drinking water production, thus an appropriate water treatment is essential to remove potential pathogens. Further samplings are in progress to locate potential drinking water source areas with lower risk of contaminations.<br>
Financial support by the German Ministry of Education and Research (BMBF) is gratefully acknowledged (ViWat: Engineering, 02WCL1474G). |
