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Tracking the oil spill (downtoearth,)

Concerns are elevating over the oil spill near Chennai, as revised estimates present proof of a much larger environmental disaster. In a new development, the Centre on February 4, has claimed that over 65 tonnes of sludge has been removed from the sea, and 90 per cent of the work is completed.

On the other hand, Tamil Nadu fisheries minister D Jayakumar, speaking to reporters on February 3, said nearly 85 per cent oil has been removed from the sea. The coast guard claimed that 72 tonnes of oil sludge has been removed.

Another media report claimed that the size of the spill was around 116 tonnes and would take 10 more days to be cleaned.

The scale of oil spill was initially estimated to be around 200 litres. The number was later updated to two tonnes and then three tonnes. It was revised again to 20 tonnes and later, 40 tonnes. The changing estimations and unsynchronised statements by officials not only raise questions on our ability to understand a disaster but more importantly, on our preparedness and ability to respond to it.

Nearly half a dozen turtles died near the north Chennai shoreline (Credit: iStock)
Nearly half a dozen turtles died near the north Chennai shoreline (Credit: iStock)

Chronology of the disaster

In the wee hours of January 28, two cargo ships collided off the suburban Ennore port near Chennai. The accident took place when “M T BW Maple” of Isle of Man was leaving the Kamarajar port after emptying Liquefied Petroleum Gas (LPG) and M T Dawn, Kanchipuram, loaded with petroleum oil lubricant (POL) was on its way to Ennore.
There was no casualty in the crew of the two ships, but impact has been showing on marine life in the region. While a section of the sea water had blackened after the spill, nearly half a dozen turtles died near the north Chennai shoreline.
As experts from the Anna University try to assess the scale of spill and area covered by the help of an unmanned vehicle, environmentalists are worried about long-term consequence of the oil spill. "The spill will affect oxygen supply to aquatic species. More species will die. But we are not able to assess the loss as we don't have a base line," said Emily Titus, an environmentalist.
Around 74 km-long coastline in and near Chennai has been affected and tar balls have collected in a 12 km stretch. As per the Coast Guard, the worst affected areas will be treated with bacteria.
Coast Guard men, engineering students and fishermen were seen using their hands to clear the oil spill in the sea. They resorted to manual cleaning after Chennai Metro Water’s super suckers failed to pump out the thickening sludge. On February 2, at least 1,000 volunteers were employed for physically removing blobs of oil deposited along the beaches.
Indian Oil Corporation (IOC) has delivered bio-remediation material for treatment of the collected oil sludge for safe disposal
The defence ministry invited reporters to travel with Coast Guard officials on a ship from Ennore to Mahabalipuram on February 3, to review the extent of oil spill.
On the same day, Madras High Court asked the state government to take urgent action on the oil spill, while deliberating on a public interest litigation filed by the president of National Union of Fishermen. The court also pointed out that one of the vessels is from Iran and that the state government must take urgent action in this regard.
The Ministry of Environment, Forest and Climate Change has issued a notice to the Kamarajar port authorities, asking if it had installed necessary infrastructure needed to deal with situations like these.
An application on the oil spill has also been filed with the National Green Tribunal, which will be heard on February 20.
ANALYSIS Extent of damage to ecology and economy unknown

by Shreeshan Venkatesh

Authorities have been quoting different scales of damage due to the spill (Credit: iStock)
Authorities have been quoting different scales of damage due to the spill (Credit: iStock)

In the early hours of January 28, as the sun was ascending the horizon on the east, a “minor collision” was reported off the Kamarajar Port in Ennore near Chennai. The boats involved were an oil tanker and an LPG tanker. This in itself should have been enough to set off alarms, but the port was quick on insisting that there was no environmental or oil damage due to the accident. The oil spill that has ensued may now become the largest ever in the southern peninsula.

By the next day, fishermen started noticing patches of dark viscous oily sludge. Minister of State for Road Transport & Highways, Shipping Pon Radhakrishnan arrived on the spot of the collision and once again allayed fears by repeating the port stance that the accident was a minor one and everything was under control. By the next day, oily patches started getting noticed and the clean up process was initiated. An early estimate put out by the port was that only about 1 million tonnes of toxic oil were spilt during after the accident. But as fishermen, volunteers and coast guard scampered to clean up the mess manually armed only with mops, buckets and tanks, it was evident that the spill was much bigger. By Thursday, February 2, the Indian National Centre for Ocean Iformation Services (INCOIS) estimated that over 40 tonnes of oil sludge and 27 tonnes of oil-water mixture had been removed. And the spill has continued to spread and has reached Chennai’s famed Marina beach. Estimates have now been revised further upwards- closer to 100 million tonnes. If you thought 1 million tonnes of toxic oil spillage was bad, the latest news is that reality could be a hundred times worse.

It has taken a whole week of frantic for authorities and the courts to wake up and start issuing orders for inquiries and arrests. Union transport minister Nitin Gadkari was finally available yesterday to issue the standard threat of probing the truth and nailing the guilty within a month.

There are at least two examples of criminal neglect that have culminated in the disaster unfolding on Tamil Nadu’s coast. The first, immediate and the most obvious is how the accident came to be. After the initial ambiguity put forth by the port, it has become clear that the “minor” collision happened as the ships tried use the port channel at the same time. According to the rules, only ship can exit or enter the port at any given time. However on Jan 28, the pilot of LPG tanker BW Maple disembarked to the port channel before the scheduled time allegedly on orders from the ship’s master. In the absence of a guiding pilot, the tanker rammed into petroleum carrier Dawn Kanchipuram and snapped the fuel pipeline of the cargo ship. On Friday, a case was registered  under sections 280 (rash navigation of vessel), 285 (negligent conduct with respect to fire or combustible matter), 336 (act endangering life or personal safety of others), 427 (mischief causing damage to the amount of fifty rupees), 431 (mischief by injury to public road, bridge, river or channel) of the India Penal Code.

While crews of the ships are being interrogated and arrest orders have been issued against the captains, if the Union Minister is serious about getting to the bottom of the disaster that has unfolded will take a lot more than just rounding up the easy scapegoats.

The fact that what was construed to be a minor incident has overwhelmed the state to such an extent that it is on its way to becoming a major environmental crisis is worrisome to say the least. It points at complete lack of effectiveness of the nation’s contingency plan. India has a coastline in excess of 7,500 km and territorial sea area close to 2,00,00 sq km. The National Oil Spill- Disaster Contingency Plan (NOS-DCP) was sanctioned in 1993, drafted in 1995 and adopted in 1996. In the two decades since then, the plan has routinely been updated and revised to reflect the latest in international safety and regulatory standards. Evidently, the only thing it reflects is a complete failure in action.

The requirement of a state contingency plan from states has been demanded by the Indian coastguard now for over 20 years now. The same was reiterated as recently as in August 2016 in the 21st annual meeting of the NOS-DCP and during the most recent meetings of the State Coastal Zone Management Authority. Despite this, Tamil Nadu has till date not furnished such a plan. For the past three years, the Tamil Nadu Maritime Board has been working on a draft for the plan.

It remains to be seen what the true extent of damage on the ecology and economy will be but what is clear from the disarray that followed the spill is that far from a contingency plan, even basic coordination between the maritime board, the state disaster response team and the port authorities is absent. This despite the fact that an environmental assessment from the Kamarajar Port on modifications for the iron ore terminal clearly states an increased risk of oil spills.

At a time when India is endeavouring to increase its port capacity and connectivity through the Sagar Mala Yojana, especially for freight goods, the oil spill that is choking Chennai seemingly answers the question of whether we are prepared to handle the responsibility that comes with large scale coastal development and operations.

TECHNOLOGY Nanosheets to clean oil spills

We’re all too familiar with footage of ruptured tankers or busted rigs dumping millions of litres of oil into the sea, coating shorelines and animals in crude sludge.

Many traditional methods of cleaning oil spills, such as breaking up the oil with dispersants or skimming it off the surface, are expensive, slow, and unsafe - and often don’t really work all that well anyway.

But imagine being able to quickly and easily slurp up the floating oil - and do it over and over again using the same material? This scenario may not be far off.

In Nature Communications, we showed how we produced, probably for the first time, nanosheets that could revolutionise oil spill clean ups and water purification. Not only do our nanosheets absorb 33 times their weight in oil, they’re also recyclable. It sounds like a huge win for the environment - but what makes these nanosheets so effective?

A hole lotta pores

 A schematic of porous boron nitride nanosheet structure: layers of boron nitride, with oil molecules (black) and dyes bound to the surfaces. Weiwei Lei

We found that porous boron nitride nanosheets have a couple of properties that make them particularly suitable for absorbing organic (carbon-based) contaminants, such as oil or dyes.

The nanosheets are made of a few layers of boron nitride atomic planes, and these sheets have a large number of holes. It’s these holes that increase the surface area of the nanosheets to a huge 1,425m2 a gram.

This means one gram of porous boron nitride nanosheets has the same surface area as nearly 5.5 tennis courts - so plenty of surface for absorption.

Another advantage is that the saturated boron nitride nanosheets can be cleaned for reuse by simply heating in air for two hours. The absorbed oil is burned off, leaving the nanosheets clean and free to absorb again. To make our porous nanosheets, boron oxide powder and guanidine hydrochloride are mixed in methane and heated at 1,100C for several hours in nitrogen gas.

The guanidine hydrochloride decomposes to release several gasses that tunnel out, resulting in the formation of holes. These pores in the nanosheets provide the surface area to absorb oils and organic solvents up to 33 times its own weight.

Cleaning capabilities

Besides high absorbent capabilities, the porous boron nitride nanosheets are lightweight and hydrophobic - so they can float on as well as repel water - and will easily separate from the water surface.

In other words, the nanosheets do not absorb water. If you sprinkle them on the surface of water, they’re easily lifted off again.

Reusing the nanosheets doesn’t have to involve burning off the oil. Solvent extraction can be used as an alternative cleaning method to avoid generating potentially harmful gases from burning oil; washing with organic solvents such as ethanol (also known as drinking alcohol) enables recovery of the initial absorption capacity of porous boron nitride nanosheets.

Good for you, me, and the environment

This new material and related technology will have important impacts on environmental protection. In particular, removal of contaminants from water is of significant importance for environmental and water source protection on a global scale. Oil spillages, organic solvents and dyes discharged from textile, paper and tannery industries are primary pollutants of water sources.

Conventional methods used to solve spillages today include combustion, mechanical collection, chemical dispersants, bioremediation, and sorbent materials. But common absorbents tend to suffer from environmental incompatibility, low separation selectivity and low absorption capacity.

Our porous boron nitride nanosheets are a simple, economic and efficient way to clean up potentially-disastrous spills from water. And the sight of an oil-coated pelican, like the one pictured above, could well become a thing of the past.


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