Hatha, A A M; Abhirosh, Chandran; Sherin, Varghese; Ellen, Kandeler; Ambattu, Thomas; Asit, Mazumder(Elsevier, January 15, 2011)
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Abstract:
Microcosm studies were performed to evaluate the survival of Escherichia coli, Salmonella paratyphi and
Vibrio parahaemolyticus in water and sediment collected from the freshwater region of Vembanad Lake
(9 35◦N 76 25◦E) along the south west coast of India. All three test microorganisms showed significantly
(p < 0.01) higher survival in sediment compared to overlying water. The survival in different sediment
types with different particle size and organic carbon content revealed that sediment with small particle
size and high organic carbon content could enhance their extended survival (p < 0.05). The results indicate
that sediments of the Lake could act as a reservoir of pathogenic bacteria and exhibit a potential health
hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore,
the assessment of bacterial concentration in freshwater Lake sediments used for contact and non contact
recreation has of considerable significance for the proper assessment of microbial pollution of the
overlying water, and for the management and protection of related health risk at specific recreational
sites. Besides, assessment of the bacterial concentration in sediments can be used as a relatively stable
indicator of long term mean bacterial concentration in the water column above
Description:
International Journal of Hygiene and Environmental Health 214 (2011) 258– 264
Hatha, A A M; Abhirosh, C; Sherin, V; Thomas, A P; Abhilash, P C(Springer India, August 3, 2010)
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Abstract:
Prevalence of faecal coliform bacteria and the
survival of Escherichia coli, Vibrio parahaemolyticus and
Salmonella paratyphi were studied in the water and sediment
from Vembanadu Lake in the presence and absence
of protozoan predators. The density of faecal coliform bacteria
ranged between mean MPN value 5080–9000/100 ml
in water and 110,000–988,000/1 g in sediment (p <0.01),
which was 110 times greater than in overlying water. The
laboratory microcosm studies revealed that E. coli, V. parahaemolyticus
and S. paratyphi showed significantly higher
survival (p <0.05) potential in sediment than in overlying
water both in the presence and absence of protozoan predators.
The results indicate that Vembanadu Lake sediment
constitutes a reservoir of pathogenic bacteria and exhibits
potential health hazard from possible resuspension and subsequent
ingestion during recreational activities. Therefore,
assessment of bacterial concentration in freshwater lake sediments
used for contact and non-contact recreation is of considerable
significance for the proper assessment of microbial pollution of the overlying water and the management
and protection of related health risk at specific recreational
sites. In addition, assessment of the bacterial concentration
in sediments can be used as a relatively stable indicator of
long-term mean bacterial concentration in the water column
above.
Hatha, A A M; Abirosh, Chandran(Elsevier, January 11, 2005)
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Abstract:
Microcosm studies have been carried out to find out the relative survival of Escherichia coli and Salmonella
typhimurium in a tropical estuary. Survival has been assessed in relation to the important self-purifying parameters such
as biotic factors contained in the estuarine water, toxicity due to the dissolved organic and antibiotic substances in the
water and the sunlight. The results revealed that sunlight is the most important inactivating factor on the survival of E.
coli and S. typhimurium in the estuarine water. While the biological factors contained in the estuarine water such as
protozoans and bacteriophages also exerted considerable inactivation of these organisms, the composition of the water
with all its dissolved organic and inorganic substances was not damaging to the test organisms. Results also indicated
better survival capacity of E. coli cells under all test conditions when compared to S. typhimurium