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. 2018 Dec;25(8):1687-1695.
doi: 10.1016/j.sjbs.2016.09.018. Epub 2016 Sep 30.

Assessment of heavy metal contamination and Hg-resistant bacteria in surface water from different regions of Delhi, India

Zeeshanur Rahman  1 , Ved Pal Singh  1
Affiliations

Assessment of heavy metal contamination and Hg-resistant bacteria in surface water from different regions of Delhi, India

Zeeshanur Rahman et al. Saudi J Biol Sci. 2018 Dec.

Abstract

The present study aims to monitor the surface water quality of different regions in Delhi (India). With many physical and chemical properties, all samples had a high load of pollution in which Najafgarh drain (Nd) exhibited maximum and laboratory tap water (Ltw) minimum contamination. Water samples contained notable amounts of heavy metals including Cr, Cd, As, Cu, Pb and Hg. A total of 88 Hg-resistant bacteria were isolated from all the regions except Ltw. Among all the samples, the density of Hg-resistant bacteria was highest in sample of Nd and their morphotype heterogeneity was highest in sample collected from river Yamuna nearby Kashmiri gate (Kg). Different strains showed different patterns of resistance to different heavy metals and antibiotics. Multiple antibiotic resistance (MAR) indices were high in two samples, the highest reported in a sample taken from river Yamuna nearby Majnu ka tila (Mkt) (0.34). The 12.5% and 24.45% isolates showed β- and α-hemolytic natures, respectively that might be of pathogenic concern. In this account, high concentrations of heavy metals and their resistant bacteria in surface water have severely damaged the quality of water and their resources and produced high risk to the associated life forms.

Keywords: Antibiotic resistance; Delhi; Heavy metal contamination; Mercury (Hg); Mercury (Hg) resistant bacteria; River Yamuna.

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Figures

Figure 1
Figure 1
Geographical positions of sampling in Delhi (India). Sign formula image represents different sampling sites and sign formula image represents dumping sites of drains in river Yamuna.
Figure 2
Figure 2
Abundance and morphotype heterogeneity of Hg-resistant bacteria along with Hg concentration in different water samples.
Figure 3
Figure 3
Multiple heavy metal resistance profiles in Hg-resistant bacteria isolated from different water samples.
Figure 4
Figure 4
MAR index of Hg-resistant bacteria in different water samples. Dash line represents MAR threshold value (0.2) to differentiate the low and high risk.
Figure 5
Figure 5
Pathogenicity concern in Hg-resistant bacteria isolated from different water samples.
See this image and copyright information in PMC

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