Tasman Spirit Oil spill at Karachi caused colossal Damages
Pakistan Times Special Report

ISLAMABAD: Tasman Spirit oil spill on the Karachi coast last year caused colossal damages to environment, marine life and the human beings with contaminating approx 2062 sq kms marine area as well as affecting 300,000 people, the largest number in any oil spill in history.

Natural Resource Damage Assessment Study revealed alarming facts like damages to seabed sediments in 270 sq kms area caused by petroleum hydrocarbons and 2000 sq kms area impacted by oil and suggested reimbursement of costs incurred in responding to spill as well as compensation of financial losses and costs of the Natural Resource Damage.

"This onshore area is heavily populated, leading to estimates that perhaps 300,000 people were exposed directly to toxic petroleum vaporise during the immediate aftermath of the spill," the report recorded.

Toxic Hydrocarbon Vaporise

"This represents the largest exposure of humans to toxic hydrocarbon vaporise in any oil spill in history. As a result, many health effects were documented (see socio-economic section below)," it added.

This study that also comprises the initial studies carried out by different departments, was carried out by Pak-EPA in assistance with Mr. Steiner, an expert who conducted study of Alaska Oil Spill as well as in collaboration with the United Nations Development Programme (UNDP) and was presented to Minister for Environment, Maj. (retd) Tahir Iqbal here Tuesday.

The most oil-impacted coastal areas were observed to be Clifton and DHA Beaches, Karachi Harbour and offshore area adjacent to Clifton and DHA Beaches.

An estimated 23,000 tons of volatile organic compounds (VOCs) were release by evaporation into air from oil spill to the most popular recreational beaches of Clifton and DHA Beaches covering 16 Km coastline.

Residential Areas

Residential areas along Clifton and Sea view coast up to 6 km area were badly affected with contaminated air with high concentrations of VOCs for three weeks.

Despite a massive beach cleaning operation the oil contamination on the beaches and adjacent seawater remained prominently visible for next six months and viable for next 12 months after the incident. Of the 31,000 tons of oil spilled, less than one per cent (310 tons) was recovered by cleanup operations.

The NRDA studies confirmed, the oil-spill severely damaged the marine ecosystem of the coastal waters of Karachi Harbour, Clifton and DHA Coasts up to Western Coast of Bundal Island.

Facts revealed, the negative impacts on socio-economy of coastal population of about 305,000 in the affected area, particularly on public health, were serious and prolonged.

The poor water quality affected entire ecosystem and virtually all living organisms in the area including commercial species of fish and shellfish as well as the marine food chain.

Water Quality

The water quality remained un-acceptable for more than six months with the concentration of oil in the surface seawater to be 5-10 mg/1 (parts per million) in the near-shore areas.

As a direct impact of the spill, oil contamination in seabed sediment has become un-acceptable after TSOS and remains so till to date.

Oil concentration in bottom sediment was observed to be from 100 ppm (parts per million) - 350 ppm in the near-shore areas while high concentrations up to 2,700 ppm in some sediments immediately after the spill.

Oil concentrations remained high in sediment even three months after the spill and in sea bed sediments of an area of about 270 sq km is high and this oil has been positively fingerprinted as Tasman Spirit oil.

The oil content also affected the dissolved oxygen content of seawater in the affected area as 16,000 tones oil 51 per cent of the total oil load in the tanker reached the seabed when the tanker sunk.

Reasons behind Episode

Report revealed, the oil deposition occurred because of the extreme turbulent mixing of the sea by strong monsoon winds after the spill, which caused the oil to attach to the suspended sediment and sink to the seabed and the seabed remains heavily contaminated.

Studies estimated that about 12,000 tons of the Tasman Spirit oil evaporated in few weeks after the spill and this toxic plume drifted with onshore winds over a heavily populated coastal area.

High levels of Volatile Organic Compounds (VOCs) were reported over a 75 km2 area with the VOC levels from 44 ppm at Shireen Jinah Colony up to 179 ppm at Village restaurant were reported on August 20, 2003.

The populated water and sediment habitats are feared to lead to make the habitat ecologically unsuitable for the normal growth and propagation of may marine organisms.

It is therefore, likely that the oil-impacted region may continue for several years to exhibit a reduction in the species diversity, reduction or depletion of wild stocks of vulnerable species, reduction in reproductive capacities, disruption in growth rates, accumulation of toxic fractions of hydrocarbons such as Polynuclear Aromatic Hydrocarbons (PAHs), and may also produce synergistic negative effects on the metabolic processes and reproductive physiology of the marine organisms living in the oil polluted habitats.

High levels of PAHs were reported in many tissue sampled up to 74 ppb (parts per billion) in some organisms. Studies elsewhere have demonstrated that PAH levels as low as 1 ppb are known to produce toxic, long-term effects.

Fish, The Victims

The oil significantly affected fish and shellfish populations and commercial fisheries in the coastal area of Karachi with a complete loss of the small-scale fishery for some time in the oil-spill affected zone.

Based on data from bottom trawling, the immediate effect of the oil spill caused mass mortality among the coastal fishes resulting in a drastic reduction in flat fishes and mullet populations in the area. High concentrations of toxic PAHs were observed in all the fishes caught from the oil-impacted area.

Long-term fisher impacts include contamination of habitat, poor hatching of fish and shellfish eggs and delayed recruitment losses to commercial fish stocks. Considering the cumulative effects, the expected time for full recovery of fisheries is 5-7 years and bird populations feeding in waters within sea area of about 200 sq km contaminated with oil, will continue to affect by ingestion of oil fractions.

Several direct mortalities of dolphins in the affected area were observed and a direct mortality for a few sea turtles recovered in the carcass surveys. Sub-lethal effects are expected in affected turtle population as turtles feeding in waters within sea area of about 200 sq km could still be oil contaminated.

Significant levels of PAHs were detected in turtles blood and egg tissue in 2003 nesting period. Oil impacted a mangrove forest area estimated at approximately 786 hectares (or 2435 acres). Mangrove seedling survival rate dropped from 30 per cent-a loss of 51,135,000 seedlings for mangrove Avicennia marina.

The health toxic effects caused mortalities of the mangroves by heavy oil while a loss of expected production of 2526 tons of shrimp and fish per year in the lost mangrove area would result.

Anxiety Disorders

Oil spill also caused colossal social injury recording increase in anxiety disorders, hopelessness, depression as well as health impacts like nosebleeds, nausea, fainting, memory loss, and chest pain were reported to increase immediately after the spill.

The most affected group of residents was coastal fishermen, who reported a 100 per cent loss of income during the 6 months subsequent to the spill.

Although surface water quality has improved dramatically, sediments remain heavily contaminated and it is not feasible to dredge and clean the vast area that is contaminated.

However, full recovery is not expected to take place until all of the spilled oil from the Tasman Spirit in seabed sediments is gone or stops leaching out the water column above.

Long Way to Go

It is expected to take 5-7 years except some areas where oil may remain buried in the seabed sediments for longer periods and full recovery may take 5-10 years. The report also suggested three primary categories of compensation essentially to be paid by Responsible Party for the Tasman Spirit Oil Spill.

These categories include reimbursement of all direct government costs incurred in responding to the spill (for all federal and provincial agencies), Compensatory/financial losses of income and earning potential (fishermen,residents, hawkers, businesses, etc. and the Natural Resource Damager/Restoration costs. ●