September 4, 2003

Fouad M. Khan reports on the hazardous effects of the oil spill caused by Tasman Spirit in Karachi

On the morning of March 23, 1989, Exxon Shipping Company’s Valdez oil tanker was maneuvering through the Valdez Narrows, near Prince William Sound, Alaska. In order to go around an iceberg, the reportedly drunken captain Hazelwood ordered the tanker to steer a little off route. Later he handed over the ship to third mate Gregory Cousins with specific instructions to steer the ship back into shipping lane once the hurdle was circumvented. Cousins, who had been on duty 12 straight hours, forgot to follow the order and around noon that day the ship got stuck on Bligh Reef. Soon the single hulled oil tanker started to leak. The rest, as they say, is history.

In the worst environmental spill disaster of all times, nearly 37,000 tons of oil was lost, and a 1300 mile long coastal stretch was affected. More than $2 billion were spent on the restoration effort over a period of more than ten years, and according to the last official count, about “250,000 seabirds, 2,800 sea otters, 300 harbor seals, 250 bald eagles, up to 22 killer whales, and billions of salmon and herring eggs,” were annihilated.

The punchline that lends perspective to all this is that, on the scale of environmental cost, Tasman Spirit has the potential to be bigger than Exxon Valdez, Alaska, because in Karachi, unlike in Alaska or for that matter in any other major oceanic oil spill incident so far, the most valuable environmental receptor of all i.e., human health is in danger.

How can an oil spill one kilometer off the coast of Karachi affect the health of human receptors living or working in the much-coveted real estates of Clifton? In order to realize the answer to this question we’d have to understand what happens to the oil once it gets spilled in the ocean from a tanker like Tasman Spirit.

As the oil leaks it retains on top of water, being generally lighter than water. A thin non-uniformly dense layer of oil starts to form on the ocean surface; this is called the oil slick. This layer of black coloured contaminant often covering several hundred kilometers of ocean surface and coastal belts in its stretch is the very first of the environmental impacts of a spill, resulting in great damage to the aesthetics of the affected area. The fate of the oil after it has formed into a slick is determined by a number of factors including the chemical composition of the spilled products, the climatic, hydrogeological and microbiological profile of the ambience.

Most crude oil and oil products are primarily hydrocarbons, i.e., carbon based organic structures just like the proteins that constitute life on planet earth. Oils generally consist of a number of hydrocarbons with different chemical compositions and a number of carbon atoms in a molecule. The greater the carbon number or number of carbon atoms in a molecule, the heavier the hydrocarbon would be.

There are some lighter hydrocarbons with carbon numbers less than nine that are light enough to easily volatilize in the ambient air, these are called Volatile Organic Compounds or VOCs. Other heavier fractions of spilled oil generally settle down to the bottom of the ocean surface in the form of a tar like coating, which can be very harmful to deep sea life especially flora. Some of the slick gets dispersed due to wave motion and forms into tiny droplets of oil spread on a large area thereby decreasing concentration of contaminants and potentially increasing rate of biodegradation.

Biodegradation is a process by which some hydrocarbon contaminants are consumed by microbiological organisms and are converted into harmless organics. This is one feasible means of natural remediation of oil spill contamination. Since dispersal of hydrocarbons helps in bioremediation, chemical dispersants such as those sprayed near the Karachi beach are used to aid the wave motion in breaking oil slicks.

Emulsification, however, is still deemed the worst-case scenario for oil spills. This involves the formation of an emulsion by mixing of oil with water. The emulsion usually accumulates along the coastline in the shape of a brown coloured layer much more persistent than a slick and the emulsion volume can be up to four times as much as that of the original spill. The best way to avoid emulsification is timely use of dispersants.

While the authorities have been prompt enough in this case, one thing must not be forgotten when making a decision regarding use of dispersants: enough caution is almost never enough.

Most dispersants are toxic in nature and care should be taken while spraying them along coasts that are in close proximity of resident human populations, such as Clifton, and where dilution can be a problem, which it can be bearing in mind the oceanography of this coastal belt.

At present, the documented methods of oil spill management aren’t that concerned with the direct impacts of spill on human health, and are more geared towards avoiding an ecological catastrophe. While this works well in most cases, some specific environmental, climatic, and social factors have rendered human health effects the prime cause of concern in dealing with the Tasman Spirit oil spill.

The most worrying phenomenon has been the presence of sickening hydrocarbon fumes in residential areas along the coastal belt. Any hydrocarbon contamination can affect human health in three ways: inhalation or intake through respiratory tract, ingestion or oral intake, and dermal or contact with skin. Already, inhalation of VOCs, presently found in excessive concentrations in air in the coastal regions, has caused harm to the health of many human receptors including famously enough, two foreign experts.

A phenomenon called photo-oxidation has been responsible for excess volatilization of hydrocarbons. The scorching sun and spread out slick on a relatively calmer surface caused hydrocarbons to react with ambient oxygen or photo-oxidize and evaporate in air. The monsoon currents then carried the VOCs towards the land and into the residential areas.

At one point, immediately after the first leakage, VOC concentrations as high as 179 parts for every million parts of air (ppm) were recorded. In later days, however, these readings stabilized to about 20 ppm. I am sure these figures won’t be ringing any bells in your ears so I guess it’s time to treat you with a little perspective again.

The most extensive research ever on VOCs and their adverse effects was carried out by the United States Environmental Protection Agency (USEPA) in the rubble of the World Trade Center and the rest of New York after 9/11. USEPA identified 90 different VOCs, which could potentially be harmful for human health. Out of so many VOCs a group of four had been generally regarded in the environmental circles with even more fearsome respect. These four were Benzene, Toluene, Ethyl Benzene, Xylenes and they went by the clan name BTEX.

Amongst BTEX, Benzene is a known carcinogen i.e., it can cause cancer provided the dangerous exposure limits are exceeded. Similarly Xylenes are expected to be carcinogenic and further research is underway. In order to be conservative about health hazards without causing unnecessary panic, USEPA came up with the Risk Based Level (RBL) of 0.02 ppm for Benzene. According to USEPA, if an average person were to be exposed to concentrations higher than this for one continuous year, some harm to his/her health would be almost eminent. USEPA also developed RBLs for other VOCs which are available on their website.

While at present there is not enough data to indict Clifton air of causing cancer to its inhalers, the chances of 20 ppm of VOCs containing at least 0.02 ppm Benzene are very high. In order to exercise even the least bit of caution, continuous monitoring as well as further testing is required.

While long-term exposures to meager concentrations can be dangerous, short-term exposures (STE) to very high concentrations, the likes of 179 ppm can be downright poisonous. No wonder the foreign experts and so many others were caught off guard. It must also be noted that what most people have experienced i.e., nausea, sore throat and headaches have been regarded in most studies as just symptoms of STE, not the actual effects.

What compounds the problems even more is the fact that this oil spill has in fact happened along the coast of Pakistan; the land of the brave. Is there anything that can scare us? Is there anything in this world, short of a brain tumor or a bullet in the head that can establish reality in our perceptions, as it exists in the real world?

Since this incident has happened everyone from the jamadaar to our beloved leader President Musharraf has been photographed doing his or her thing on the Karachi beach. Hardly one single person of all those who’ve ostensibly visited the site, including the experts, was in proper protective gear — comprising of at least a real gas mask (not the particle filter cops have been wearing), and gloves and long boots made of impermeable leather.

Let me explain to you that while developed countries have conducted enough research for us to know for sure that the presence of Benzene and company can be harmful for human health, their studies have seldom taken into account the effects of direct dermal contact with contaminants.

They assume that everyone involved is wearing enough protection to avoid extensive contact. Little do they know that the cleanup crew in this country cannot work with their shoes on as they find it “uncomfortable.” Some studies specifically state that though dermal contact has not been considered in developing standards, it can contribute to the harm significantly and must be avoided.

Therefore, do not rush to the beach to “see the oil spill”. It’s not a spectacle, it’s a disaster; do not try to become a part of it. If you feel there’s too much hydrocarbon smell in your house or neighborhood, inform the authorities and evacuate.

If you live or work in Clifton or Defence and have been feeling nauseous, or have had headaches, immediately consult a medical practitioner. And last but not least, if it rains in the next few weeks or so, stay indoors. Forget the pleasures of the monsoon; it might be pouring acid out there.

The writer is an environmental consultant with specialization in risk-based assessments of hydrocarbon soil and groundwater contamination.

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