The impact of industrial activity on aquatic fauna found at bottom of the Arabian sea (macrobenthic communities) in the sensitive ecosystem of the Marine National Park and Sanctuary (MNPS) in southern Gulf of Kutch was found to be low despite various anthropogenic pressures in the region, according to a study conducted by the National Institute of Oceanography (NIO), Goa.
The recently released study conducted in three industrialised zones in the MNPS namely Mithapur-Okha, Vadinar and Sikka, also concluded that water quality values fulfilled the criteria of Central Pollution Control Board (CPCB) for eco-sensitive zones despite the various stressors operational in the region.
The Gulf of Kachchh Marine National Park and Sanctuary (MNPS) has one of the four coral reef systems of India. However, owing to its unique geographical position, this area has been transformed into an industrial hub dominated by oil and gas production, refining and transportation facilities.
The NIO study was designed to evaluate the bio-diversity and distribution of the macrobenthos at three select industrialised locations of MNPS (Mithapur-Okha, Vadinar and Sikka) and study the impact of various anthropogenic pressures, if any, in the three selected areas.
The southern flank of the Gulf of Kutch, where the marine national park and sanctuary is spread in 457.92 sq km is located, has about 42 islands, most of them having fringing coral reefs. Besides these islands, the MNPS includes diverse habitat like algal beds, mangrove swamp forests, reef vegetation, scrub forests, marsh vegetation, vast intertidal rocky and sandy stretches, mudflats and water mass extending up to the 18 mt depth.
The three industrial zones selected for the study are located near the marine sanctuary are home to manufacturing unit of some of the big industrial groups. Mithapur houses integrated salt works and inorganic chemical complex of Tata Group's Tata Chemicals Ltd which releases its industrial effluents into the Arambhada bay through an open channel in the MNPS. Okha has an all weather port with direct berthing facilities handling coke, coal, wheat, fertilizers, clinker, chemicals and soda ash, under the Gujarat Maritime Board (GMB).
While two oil terminals, a refinery, two crude oil tank farms, three Single Point Moorings (SPMs), owned by Essar Group's Essar Oil and Essar Ports are located in Vadinar.
Sikka, located adjacent to Vadinar, has a state-owned thermal power plant, a cement factory, a private jetty, an extensive pipeline network for unloading crude oil and exporting petroleum products, a liquid cargo jetty and another crude oil tank farm located along its coast. India's largest all-weather petroleum terminal -- Reliance Jamnagar Marine Terminal (RJMT) -- is also based at Sikka.
"The present investigation provides evidence that although pockets of higher stress to benthic fauna can occasionally occur, the impact of industrial activity on macrobenthic communities in this diverse but sensitive ecosystem in the protected waters of the coralline southern GoK is probably low," the NIO study concluded.
"The results also indicate that the study area did not receive much anthropogenic discharge of nutrients and the land runoff was negligible. Although the effluents discharged off Vadinar and Sikka had higher salinities, the receiving water exhibited normal salinities suggesting effective dispersal of the effluent after release," it further stated.
However, it found "Effluent dispersal was not as effective at Mithapur as evidenced by higher salinity and petroleum hydrocarbons -water levels measured near the discharge point compared to other stations in the zone."
"Water quality values of the current study fulfill the criteria of CPCB for ecosensitive zones despite the various stressors operational in the region. The present DO (dissolved oxygen) values were also comparable with historical data suggesting consistent DO levels that were not influenced by the industrial activities," the study further concluded.