Heavy metal concentration in marine water: An assessment of ONGC’s blocks in Mumbai High Region, Arabian Sea

Heavy metal pollution, in the aquatic ecosystem, has become an area of concern garnering increasing attention since the past few decades. Some metals like manganese (Mn), copper (Cu), iron (Fe) and zinc (Zn) are biologically important for marine life. Other non-essential metals like lead (Pb), cadmium (Cd), and Arsenic (As) become toxic at higher concentrations. These metals are introduced into the marine ecosystem mainly due to anthropogenic activities. Hence, monitoring the heavy metal concentrations in these marine water over a period of time is of great help in checking the pollution level and identifying the trend, which in turn will be instrumental in formulating sustainable practices.

The paper mainly focuses on the study of the concentration of lead (Pb), cadmium (Cd), and Arsenic (As) in sea water around the operational areas of ONGC in Waestern offshore. The distribution of heavy metals in the seawater of ONGC’s exploratory blocks in Mumbai High Region, Arabian Sea was studied. Fifty four sea water samples were collected as per OSPAR Commission guidelines from each blocks (Block A, Block B, Block C, Block D and Block E) of Mumbai High Region, Arabian Sea and processed samples were analyzed by ICP-MS for Pb, As, and Cd. Comparison of average results in studied 5 blocks with various seawater quality guidelines is discussed to assess the present level of contamination. The study reveals that seawater in study area is not contaminated with respect to perceived heavy metals. Generated data will assist in future for proactive measures to minimize the impact of anthropogenic sources.