Oil spill clean-up nears end

Over the last two weeks, the Department of Environmental Health has recovered 1,700-2,000 gallons of used oil that spilled into the canal near the George Town Landfill during Hurricane Ivan.

The operation, which did not use chemicals, was assisted by Texas A & M University’s National Spill Control School (NSCS) and local agencies. To date, the DEH has recovered more than 10,000 gallons, according to a GIS press release.

A team from the school arrived on Grand Cayman on 3 March to assist with the actual clean-up phase of the oil spill, located at the north-western end of the George Town Sanitary Landfill. The project is nearing completion, as reported in the Caymanian Compass 11 March.

‘Consultants from the NSCS have been invaluable in assisting the DEH in this phase of our recovery operation,’ said Chief Environmental Health Officer Roydell Carter.

During Hurricane Ivan, a five-foot-plus surge swept through the landfill from the North Sound, dislodging drums containing used oil. The drums had been stored at the landfill’s recycling area awaiting shipment to a recycling operation overseas.

At the request of the DEH, Roy Coons and David Jensen of NSCS visited the island 1-4 February 2005 for a preliminary assessment of the landfill cleanup operation, and submitted recommendations for the remainder of the project.

On their recent visit, the two experts were accompanied by colleague Carl Christiansen who has more than 25 years of experience in oil-spill cleanup and previously conducted training exercises with the DEH.

‘After the consultants reviewed the work site on their first day here, the team commenced operations the next day, based on the work plan previously accepted by the DEH,’ Mr Carter said.

Isolating the oil

The process involved washing and isolating the oil, according to DEH Laboratory Senior Research Officer Antoinette Johnson.

‘The team’s approach was to wash the oil towards the earthen berm barriers that, along with oil spill booms, had been placed to contain and isolate the spilled oil and to prevent pollution.

‘This washing action allowed the free oil to pool in a layer thick enough to collect easily with skimmers. At the same time, the vegetation was being washed and oil flushed from behind the rocks at the side of the canal.’

Ms. Johnson said the skimming process was complicated by the large amount of debris within the canal, so a team of DEH workers assisted with the hand removal of the leaves and other detritus to prevent clogging the skimmer.

Oil and water collected were pumped into collection tanks and allowed to settle, at which point the water was drained back into the canal to repeat the cycle.

Oil-soaked debris

Marl and mulch were laid to firm the dyke road surface and soak up oil to prevent further runoff into the canals. Oil-soaked debris that had trapped oil in pockets was also removed. The team preserved as much live vegetation as possible and rinsed the tree roots of accumulated oil, removing any dead vegetation that was trapping the oil.

Additional checks of the site are planned, according to Mr. Carter. ‘Monitoring of the site will be ongoing and any small remnants of oil that may accumulate will be removed.

‘All of these procedures deliberately avoided the use of chemicals or other harsh methods in an attempt to minimize the damage to the surrounding mangroves,’ said Mr. Carter.

Samples from the site will be collected for analysis next week and in three to four months, added Ms. Johnson.

‘By isolating the contamination, removing the bulk of the spilled product and washing the vegetation, natural bio-remediation of any residue can now proceed,’ she said.

NSCS estimates that within four to six months the majority of residual staining and clearing of residue of tree roots and canals should be completed. Therefore, there should be no permanent damage caused by the oil spill.

‘Several agencies have given their assistance to this project, including lending equipment and expertise. These include the Department of Environment, Mosquito Research and Control Unit, Petroleum Inspectorate, Water Authority-Cayman and the Cayman Islands Recovery Operation,’ Mr. Carter said.

He praised several aspects of the project including the utilisation of local resources, the absence of chemicals and quick clean-up procedures.

Mr. Carter also thanked the overseas consultants who provided planning and training support. ‘Our staff has now experienced first hand this kind of environmental clean-up.

‘While we will do everything to minimise the likelihood of a similar incident, the knowledge gained from this experience will allow any future response, if needed, to be faster and more focused,’ he said.

He added that some staff received recertification in handling hazardous materials due to their level of involvement and management of the project.

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