CHENNAI: A Year has passed since the oil spill off Ennore coast on January 28, 2017. Till date, the State government has not made any effort to assess the extent of environmental damage caused by the incident.
A detailed long-term monitoring programme on health of larvae, benthic organisms, turtles and birds during the post-spill period is what is needed to understand the extent of recovery of biological system and the likely period that would take for complete recovery of the ecosystem in the spill-affected Ennore and Marina coasts.
The Committee on Assessment of Environmental Impact of Oil Spill constituted by State Department of Environment three months after the incident submitted its report in June last year. It is now gathering dust even as Central and State research institutes are awaiting funds to commence studies on various aspects, including fisheries.
The 93-page report, which is accessed by Express, has cautioned the government on safety of people consuming fish caught in oil spill affected areas. The Central Marine Fisheries Research Institute (CMFRI) has made preliminary assessment of impact of oil spill on fisheries, off the Chennai coast. Also, Integrated Coastal and Marine Area Management Project Directorate (ICMAM) carried out analysis of Total Petroleum Hydrocarbons (TPH) in edible fish caught using trawl nets operated by fishing trawlers at depths of about 10m.
The analysis showed 21 species were contaminated by TPH as high as 4.51 µg/g. While a majority of the edible fish recorded TPH levels less than 2 µg/g, only one species, namely Anodontostoma chacunda, commonly called as Gizzard shad, which was caught in trawl net close to the collision site, had the highest concentration of 4.51 µg/g. No data on safe limits for TPH in fish are available, which makes it difficult to interpret whether the observed highest value of 4.51 µg/g in fish is within the safe limits. Further, absence of such data for pre-spill period makes it difficult to interpret that such a concentration of TPH is solely due to oil spill.
“It is vital to develop safe limits for TPH and Poly Aromatic Hydrocarbons (PAH) for marine organisms so that risk of consumption of contaminated edible fish could be determined and public could be adequately cautioned in future incidents,” the report reads and ICMAM proposed to do eco-toxicological studies in fish to determine the safe limits.
Chairman of the committee BR Subramanian, a former adviser for Ministry of Earth Sciences (MoES) and senior scientific consultant for National Centre for Sustainable Coastal Management (NCSCM), told Express that several of the short and long-term projects proposed by the research institutions are under various stages of approval and funds are likely to be released very soon.
“This is the first oil spill incident in Chennai and very few occurred in India. No one knows how much of environment impact it would have. Considering high viscosity of bunker oil, low reactivity and persistency in the environment, it is certain that it would continue to be present in the sediments and sessile as well as bottom living organisms at least for a period of 5-8 years,” he said.
As per the report, seven short and long term study projects were proposed by National Centre for Sustainable Coastal Management, ICMAMPD, Indian Inst itute of Technology (IIT)- Madras, Central Marine Fisheries Research Institute, Institute for Ocean Management, Government of Tamil Nadu’s departments for Environment, Health, Fisheries and Forests; Maritime and Pollution Control Boards, Care Earth Trust and Kamarajar Port Ltd. The total cost of the projects comes to `5.68 cr, but till today not a single project has commenced.
A scientist at CMFRI said the government should approve the projects immediately. The more the delay, the more complex it would become. For instance, Exxon Valdez in 1989 in USA, was involved in a spill of about 41000 tonnes of crude oil in the Alaska coast that wiped out the fishery and caused extensive damage to marine organisms and beaches. Its impact is being felt even 25 years after the incident.
“Due to its high viscosity and density, the bunker oil sinks to the bottom.
The bunker oil being less reactive and persistent in the environment, its adverse impact on environment, especially on sessile and benthic organisms will continue over a period of time. These organisms may show retarded growth and their population may diminish over the years partly affecting food chain in the sea,” the report said.
Oil spill incidents in Indian waters
1 The largest reported is the oil spill off Kiltan island of Lakshadweep. In 1974, grounding of American tanker Transuran led to a massive oil spill, which practically damaged the entire coral reef of the island.
2 Two others are accidents involving MT Khalija and MSC Chitra off Mumbai in 2012, spilling about 800 tonnes of oil and the leak of crude oil from an ONGC pipeline near Uran in Maharashtra in 2013. The environmental damages caused include contamination of beaches of Mumbai, impact on mangroves in the creeks nearby and boulders by oil besides oil patches in the shallow sea.