PHYTOCONTROL STRATEGIES USING SILVER NANOPARTICLES AND ACTIVATED CARBON AGAINST COLIFORMS IN WATER
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Date
2023-03-23
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY
Abstract
Water quality is one of the most important factors for a sustainable andhealthy ecosystem. The present study was undertaken to evaluate phytocontrol strategies using silver nanoparticles and activated carbon against coliforms in
water. A total of 100 water samples were evaluated for coliforms and coliphages and its physico-chemical parameters. Samples included 85 well water samples received at the NABL accredited laboratory of the Department of Veterinary
Public Health, CVAS, Mannuthy and 15 river water samples collected from various parts of Thrissur district. The samples were evaluated for total coliform count using Most Probable Number (MPN) method, which revealed 88 positive
samples exceeding the WHO recommended limit of 10 MPN index/100 mL. These positive samples were subjected to isolation and identification of E. coli of which 57 E. coli positive samples were further subjected to isolation and
identification of coliphages in water using Double Agar Layer Method. A total of five samples positive for coliphages were obtained and of these, the concentration of coliphages were more in river water samples (60 per cent) compared to well water (40 per cent). From the water samples positive for coliforms, six samples were selected at random for finding the efficacy of a bioadsorbent filter column which was prepared in the laboratory. This consisted of a layer of activated carbon sandwiched between sterilised sand layers within a Poly vinyl chloride (PVC) pipe. Two filters of two different diameters (20 mm and 25 mm) were assembled. The activated carbon used in the filter was made from the stems and leaves of cassava plant. All the water samples (unfiltered and filtered) were assessed for physico-chemical parameters and coliform count. The filter column of 20 mm diameter did not reduce the coliform count significantly but the filter with 25 mm diameter reduced the coliform count of the water. The layer thickness and flow rate of the filtered water were also estimated. The qualitative phytochemical screening and antibacterial effect of silver nanoparticles prepared from the hot aqueous extract of fresh neem leaves was also determined. The silver nanoparticles were characterised using X ray diffraction analysis which revealed a good yield of silver nanoparticles. The in vitro antibacterial activity of the
synthesised silver nanoparticles revealed that silver nanoparticles have antibacterial activity and showed a zone of inhibition ranging from 6 mm to 16 mm against Gram negative standard culture of E. coli (MTCC 13706) and no
activity against three PCR confirmed isolates. This study suggested that efficient control measures should be advocated to control the quality of our water resources.