ISLAMABAD, Nov 30: The Federal Environment Ministry released on Tuesday a report on the oil spill caused by Tasman Spirit off the Karachi coast last year, suggesting a serious damage to all components of the ecosystem , besides affecting a coastal population of 305,000.

The report - Natural Resource Damage Assessment (NRDA) - is prepared by the Pakistan Environmental Protection Agency and the Ministry of Environment with the support of the United Nations Development Programme to determine the extent and severity of ecological harm caused by the oil spill in July 2003. The study is completed with the assistance of international and national experts.

Tasman Spirit was carrying 67,535 tons of light crude oil for delivery to the Pakistan Refinery Limited in Karachi. As a result of the spill, around 31,000 tons of oil was leaked into the surrounding waters.

The report supported earlier estimates that the environmental, social, and economic damage from the oil spill was serious and extensive. Studies revealed that a marine area of approximately 2,062 sq-km was contaminated with petroleum hydrocarbons.

The seabed sediments in an area of 270 sq-km were found to be affected by oil that was analytically fingerprinted to Tasman Spirit, while the area of marine waters swiped by oil spill was estimated to be more than 2,000 sq-km.

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 12,000 tons of volatile organic compounds (VOCs) were released by evaporation into the air from the oil spill.

The worst oil-impacted areas of Karachi coast included the most popular recreational beaches of Clifton and the DHA. Residential areas along the Clifton and Sea view coast up to a six-kilometre region were badly affected with contaminated air, having high concentrations of VOCs for about three weeks.

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

The NRDA studies confirmed that the oil spill severely damaged the marine ecosystem of the coastal waters of Karachi Harbour, Clifton and DHA coasts up to the western coast of Bundal Island.

The NRDA programme has methodically documented the large-scale mortalities of bottom organisms and fish, including commercial fish and shellfish, and other marine organisms caused by the spill.

Also recorded were significant impacts to populations of birds, mammals, sea turtles, and mangroves in the oil-affected zone. The negative impacts on the socio-economy of the coastal population of about 305,000 in the affected area, particularly on public health, were serious and prolonged, the report said.