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Relative inactivation of faecal indicator bacteria and sewage markers in freshwater and seawater microcosms
Author(s) -
Ahmed W.,
Gyawali P.,
Sidhu J.P.S.,
Toze S.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12285
Subject(s) - precinct , geography , population , population health , archaeology , environmental health , medicine
In this study, the relative inactivation of faecal indicator bacteria ( FIB ) namely E scherichia coli , enterococci and sewage markers [ B acteroides HF183 and human adenoviruses (HAVs)] was assessed in sewage‐spiked freshwater and seawater microcosms under ambient subtropical climatic conditions. The numbers of declining FIB were measured with culture‐based methods, whereas the numbers of sewage markers were measured with q PCR assays. The T 90 inactivation times of E. coli , enterococci and the HF183 markers in both freshwater and seawater microcosms were <3·5 days, suggesting the suitability of the HF183 marker to identify recent sewage pollution events. The T 90 value of HAVs (9·4–13 days), however, was significantly higher than FIB and the HF183 marker in both freshwater ( P < 0·001) and seawater ( P < 0·05) microcosms. Therefore, we recommend that HAVs should be used as an additional marker to adequately assess the potential health risks associated with longer‐term sewage‐polluted environmental waters. Significance and Impact of the Study In this study, we have shown that the persistence of the B acteroides HF183 marker in freshwater and seawater microcosms was similar to faecal indicator bacteria ( E scherichia coli and enterococci), whereas human adenoviruses ( HAV s) persisted relatively longer. These findings suggest the suitability of both the markers to identify sewage pollution in environmental waters. However, HF183 marker appeared to be more useful than HAV s in identifying recent sewage pollution. As, HAV s may remain infective for lengthy periods, it should be used in conjunction with the HF183 marker to obtain information on the potential human health risks associated with sewage‐polluted freshwater and seawater.