Present Status of Heavy Metals in Lake Nainital, India

To evaluate heavy metal pollution status of the Lake Nainital, an eutrophic lake, situated in the Central West Himalayan region at 29 degrees 24' N latitude, 79 degrees 28' E longitude and an altitude of 1935 m above mean sea level, the assessment of heavy metals in the lake water was made from September 2016 to February 2017 using Atomic Absorption Spectrophotometer (AAS). Three sites viz., S-1 (Aeration centre at thandi sadak), S-2 (Platform near the Naina Devi Temple) and S-3 (Boat stand near bus stand) were selected and fortnightly sampling for assessing the concentration of six selected heavy metals (Lead, Cadmium, Arsenic, Zinc, Copper and Manganese) was made. The range and average concentration of heavy metals in water of Lake Nainital was observed as Zn: 0.013-0.051 (0.029 mg L-1), Pb: 0.137-0.629 (0.346 mg L-1), Cu: 0.0-0.263(0.113 mg L-1), Mn: 0.0-1.314 (0.361 mg L-1), Cd: 0.0-0.012 (0.007 mg L-1) and As: 0.0-0.004 (0.001 mg L-1). Three water quality pollution indices namely Heavy metal Pollution Index (HPI), Heavy metal Evaluation Index (HEI) and Degree of Contamination (C-d) were used to evaluate the present status of selected heavy metals. The average value of heavy metal pollution index of different metals (Zn: 0.005, Pb: 6.438, Cu: 0.066, Mn: 1.642, Cd: 0.610 and As: 0.205) show that the water of Lake Nainital is slightly affected with Mn and seriously affected with Pb pollution. Though the average value of HEI (1.448) and C-d (0.447) suggests low heavy metal pollution in the Lake Nainital, higher lead pollution is case of concern.