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Biotech tools can clean up the spill
THE Earth has faced many disasters caused by humans throughout the history. Oil spillage accidents abound today and are on record to have caused ecological and social catastrophes.
Today one of the most important hazards jeopardizing our sea environments is oil spillage from the single-hulled oil tanker MT Tasman Spirit. Heart-wrenching photographs of oil-soaked birds and heaps of dead fish have appeared in newspapers; and people living near the beach area have been reported to be suffering from respiration problems.
Is it in our hands to prevent these happening? Yes, to a large extent it is. Once the oil is spilled, it is subject to physical, chemical and biological changes. The biological weathering processes include evaporation, dissolution, dispersion, photochemical oxidation, water-in-oil emulsification, adsorption on to suspended particulate material, sinking and sedimentation.
The crude oil spill at the Karachi beach contains volatile substances, such as saturates (51 per cent), aromatics (33 per cent), resins (0.085 per cent) and asphaltenes (.075 per cent) with a few of them having low boiling points. These substances evaporate, reducing the spill by 25 per cent but in the process they release toxic substances into the atmosphere. The remaining oil is very thick and sticky, and adheres to anything that it touches — rocks, sand, marine life.
Conventional methods of dealing with oil spills would include use of dispersants or physically collecting the oil. However, dilution is not a solution and so it is important to understand the biological processes working behind the scene. As you know, biological systems can recognize and act on specific chemical structures, and can be used to decontaminate polluted water, land or air.
Biocatalysts that can come useful in this case include enzymes, specific antibody technology, and engineered or optimized cell cultures. Bioremediation technology uses natural as well as recombinant (genetically engineered), micro-organisms such as bacteria, fungi, and yeast to degrade hazardous substances into non-toxic or less toxic substances.
Huge numbers of bacteria exist naturally in the soil and the rubbish in recycling and landfill sites. Some of those bacteria slowly break down the many different types of waste. Biological treatment to solve waste or oil spill hazardous chemical problems is not a new idea.
What’s new is the greatly increased range of bio-treatments that may be made possible by biotechnology like genetically modified bacteria E. coli that fed on oil spills and cleaned it up. Its diet is limited to a variety of organic, carbon-based compounds found in oil, which divides every twenty minutes and is a vigorous and hardy species.
However, biotechnologists can use gene technology to recombine, or mix and match, the most desirable traits of several bacterial species to create genetically engineered recombinant varieties. In the future, they could, perhaps, extract the gene from one strain that allows it to break down some specific hazardous waste and the gene from another that allows it to withstand wide temperature ranges, lack of oxygen or another environmental extreme.
The ideal result is a bacterium genetically custom-made to clean up a specific problem waste at a particular site under defined conditions.
Unknown impacts Oil-decomposing germs
The full environmental impacts of the oil spill disaster at Karachi won’t be known for years. Sandstone is very porous, and soaks a lot of oil; it is harder to clean and even after that, it will keep releasing oil back into the environment with each high tide. The effects of this contamination could be widespread and long-term.
In 1989, the oil tanker Exxon Valdez released about 43 million litres of oil into the Gulf of Alaska. Since that incident, the US government has spent a lot of time and money studying the slick’s immediate and long-term effects on Alaska and its marine ecosystems.
Similarly, the Gulf War brought about some of the worst environmental pollution ever recorded as the result of oil spills. From August 1990 to February 1991, 480 million litres of oil were spilled into the Arabian, Gulf and in the Kuwait desert making this the largest oil spill in history.
In the backdrop of the oil spill disaster at Karachi, several questions are being raised: Could the incident be averted? Could the response be quicker? How much of the wildlife is harmed? What species rely upon the health of another species for survival? What can we learn from further research to improve prevention and clean-up strategies?
In such a big environmental and ecological catastrophes as people of Karachi are facing today, only biotechnology tools can solve and minimize our environmental problems in very effective and economical way. However, for the development of biotechnology in Pakistan, our ministry of environment must approve of some defined bio-safety guidelines for development and use of genetically modified organism, such as oil eating bacteria.
The writer
FOR speedy degradation of crude oil spilled from MT Tasman Spirit, microbiologists suggest spreading cow-dung as it contains naturally occurring bacteria E. Coli that is capable of degrading crude oil into simple and harmless compounds.
Allowed to degrade naturally, the oil spill will take a very long time, even decades, say environmentalists. Without introducing lab-cultured, modified micro-organisms into the oil-polluted seawater, the process of oil degradation may take several decades, say environmentalists.
Unless treated properly, highly toxic aromatic compounds in the crude oil would continue contaminating the air and underground water in Karachi, besides destroying marine eco-system, experts believe. Furthermore, if anti-slick operation is delayed, oil contamination in air and underground water might give rise to genetic disorders among children in Karachi.
“Aromatic compounds in the crude oil, including phenol, are not only cancer-causing, they are also the major cause of genetic disorders among children. Studies prove that petroleum intoxication results in loss of memory and stamina. It also causes nausea, muscle weakness and other disorders, some of which cannot be treated,” they add.
Expressing concern about spraying of dispersants, Dr Nuzhat Ahmed, Director, Centre for Molecular Genetics, University of Karachi, says, “Even after the mixing of specially modified oil-degrading bacteria into seawater, it will take at least a year for micro-organisms to degrade crude oil into simple water and carbon dioxide.”
She says through the natural way, low concentration of bacteria would take 50-60 years to break oil into simpler components.
Slowly disintegrating oil in the sea would consume all oxygen, “and all the oxygen-producing plants and algae will perish, endangering fish, shrimps, crabs and all other marine organisms,” they informed.
“What we have learnt from the last Gulf War is that Kuwaiti authorities used lab-cultured genetically modified bacteria for getting rid of oil spilled in their soil and sea and the whole process of degradation and decay took a year,” Dr Nuzhat Ahmed said.
The scientists at the CMG are already working on modification of various, bacteria. — PPI
