Assessment of mercury pollution through mercury resistant marine bacteria in Bhitarkanika mangrove ecosystem, Odisha, India

Abstract

Level of mercury pollution by estimating the number of mercury resistant marine bacteria is examined in this study. Total mercury levels in the water and sediment samples were estimated between 0.14 and 0.66 ppb (0.00014 and 0.00066 ppm) and from 0.23 to 0.97 ppb (0.00023 to 0.00097 ppm) respectively. <i>p</i>H, temperature and salinity level of the water samples were in the range of 7.13-7.16, 27.35-36.1ºC and 14.25-15.6 ppt respectively during this period. Mercury resistant marine bacteria followed the trend of mercury level and ranged from 2.60×10³ to 7.05×10⁴ CFU/mL and from 0.16×10³ to 7.4×10⁴ CFU/g in water and sediment respectively. Percentage of mercury resistant bacteria varied from 0.12 to 89.28 in water and 0.14 to 88.88 in sediment. Some of the resistant isolates (positive for <i>mer </i>operon mediated mercury resistance) were characterized further. They were found to be under the genera <i>Vibrio </i>and <i>Bacillus </i>which can resist other toxic metals (Cd, Zn, Pb, As) as well as antibiotics (AM, VA, NX, AZM, A, AC) confirming the pollution level in the ecosystem.