Navy personnel attired in protective gear cleaning debris from the stricken ship, which washed ashore. (File photo)

There is nothing we can do now for the disastrous fire on the container ship X-Press Pearl. This will certainly have serious environmental implications, where we must be guided by science rather than personal theories. Some of the academics who have their own explanations, will only confuse the general public to the extent of giving up eating fish, which is our main protein source. When these theories are given over the media there is so much hype that people tend to accept all what they say.

The shipping company is at fault for not properly containing the leak in a container transporting concentrated nitric acid. This acid is highly corrosive, as well as a strong oxidising agent. Generally, transporting such a strong acid, along with highly oxidisable organic compounds, is highly undesirable. We are not sure how the nitric acid was packed inside the container. An inert packing material such as vermiculite, which is a silicate mineral, should have been used as packing to absorb any accidental spills. In the case of a leak from a container, it should be first soaked in this type of adsorbent material, and after soaking the acid in this manner the adsorbent with the acid can be washed away with water, using a high pressure water hose. Ship crews should be trained in such disposal procedures when they transport such dangerous cargo. Shipping crews may not have a good knowledge of the chemistry involved, but they could have contacted experts on the ground with specialized knowledge in hazardous waste disposal.

There is one theory that the nitric acid spill is going to destroy the corals. There is no scientific basis for this argument. Nitric acid added to the vast expanse of the ocean gets diluted to harmless levels. NASA scientists have estimated that nitric acid formed due to lightning, which comes down with the rain, annually amounts to 8.4 million metric tons world-wide. This is part of the nitrogen cycle in nature which has been going on for millions of years. Similarly, sodium methoxide undergoes ready hydrolysis, giving sodium hydroxide and methanol, and their biological effects are minimal considering dilution in the ocean.

Some scientists have claimed that this fire will result in acid rain. Acid rain is caused by the burning of fossil fuel and coal producing sulphur dioxide and nitrogen dioxide. These dissolve in water and come down as sulphuric and nitric acids giving acid rain. While theoretically acid rain from the ship fire is a valid argument, looking at the cargo contents there are no sulphur dioxide or nitrogen dioxide sources, and only burning of ship fuel can result in sulphur dioxide which can cause acid rain. Also, since there is only one container of nitric acid, the amount of nitrogen dioxide produced will not be significant, particularly if the nitric acid goes into sea water. Vehicles in Colombo city during the combustion of fuel produce more than the possible emissions from this ship. By all accounts so far, fuel tanks are intact and apart from an oil spill, there is less likelihood of these burning, now that the ship is under water.

The real environmental issues are the plastic pellets and oil spills, and not acid rain or nitric acid. These plastic beads belong to the groups, low-density polyethylene (LDPE) and high-density polyethylene (HDPE) according to the inventory of cargo. What is really disturbing is the fate of the plastic pellets, which are washing ashore, polluting our beaches and ending up in fish. Plastic microfibres have been detected in marine fish for some time since oceans throughout the world are getting heavily polluted with plastics. Very small strands of microplastics are everywhere including our homes. For instance, our own clothes are made up of polymers which give out these, and this matter has received attention from scientists in the last few years. Similarly, soft toys and other plastic toys peel off during use and these are present in the air we breathe. Plastics can remain for at least a hundred years without breakdown. Government agencies such as the Central Environmental Authority, Marine Environment Protection Authority and National Aquatic Research Agency can undertake to monitor the presence of microplastic fibres in the flesh of fish. It is a simple test, involving observing the flesh under the microscope.

If we look at the information available, the ship carried a total of 1886 containers and the distribution of cargo (along with the number of containers in brackets) is as follows: nitric acid (1), 25,000 bags of LDPE and HDPE each weighing 25 kg (55), caustic soda (42), urea (88), lead ingots (8), lubricants (30) methanol, sodium ethoxide, vehicles and other miscellaneous items (rest of the containers). The greatest environmental concern here are the LDPE and HDPE pellets, and the lubricant oils, which can cause oil spills along with the 325 tons of ship fuel.

The question arises as to what can be done to deal with the enormous amount of plastic wastes collected in our beaches. Our plastics industry imports this product as a raw material in large quantities, to produce films for food packaging, which accounts for about 55% of global consumption. Our familiar shopping bags are also made from this polymer, and there are many other applications with injection moulding, which include household goods, toys and sporting goods, caps and various medical devices.

I wish to propose that the accumulated plastic beads be used for the plastics industry and they should be encouraged to reuse the plastic beads washed ashore. A simple gravity separation can separate the sand from the beads. Immersion in sea water, with a higher density than freshwater, can separate the beads from sand, and there is a possibility of reusing these pellets. Some of the bags collected by those who thronged the beach can be purchased, and the initiative of the plastics industry is critical in dealing with the plastic problem.

The damage to the environment caused by the X-Press is enormous, and it is doubtful whether Sri Lanka can at least partially recover the cost of the damage by way of compensation from the ship owners. In the earlier incident involving New Diamond, the Attorney General claimed damages for Rs. 3.4 billion, and according to what a government Minister stated at a recent news conference, only around Rs. 400 million has been paid. It is not clear whether Sri Lanka has signed the appropriate conventions to deal with compensation. Some of these conventions are the Bunker convention (2001), Athens convention (2002) and the London convention on limitation of liability for maritime claims (1996). For instance, Canada has enacted the Marine Liability Act in 2018 to make sure that in the event of an oil spill, compensation is available for the victims and other responders. Environmental remediation is also 100% compensable irrespective of the size of the spill.

The danger of oil pollution from 30 containers containing lubricants and the 325 tons of engine fuel should receive the attention of authorities, to procure the equipment and chemicals needed for its remediation. More importantly, we should have personnel with the necessary expertise to deal with the problem of extensive oil pollution. Oil booms are a popular and most widely used method for oil clean up, due to their simplicity and easier execution. This method has to be carried out immediately after the oil spill is detected. Once the oil is bounded by oil booms, it has to be extracted with the use of skimmers to scoop up the oil. The most effective way is to use adsorbents, and some cheap materials available for this purpose are peat moss, vermiculite and paddy straw. If the oil spill has not dispersed, it is even possible to burn the oil since oil floats on sea water. In addition, dispersants which are chemically similar to the detergents used for household washing, are used for the remediation of oil spills. These break the oil droplets into a smaller size, which makes it easier to mix with water, and the oil eating microbes will eventually ingest and break down these smaller globules.

Prof. O. A. ILLEPERUMA