Phuket Oil Spill: diesel slick drifting toward Phi Phi Islands

PHUKET: A large plume of diesel fuel emanating from the wreck of the Choke Thavorn 6 fuel tanker that sunk in heavy seas off Phuket yesterday is heading in the general direction of the Phi Phi Islands in Phuket’s neighboring province Krabi.

Crew aboard Royal Thai Navy helicopters monitoring the situation told a reporter from the state-run MCOT news agency this morning that the slick is now moving eastward.

An earlier report had the plume of pollution moving in a more southerly direction, toward international waters.

Much lighter than seawater, diesel fuel generally evaporates and disperses into water much more quickly than many other types of petrochemicals. Prevailing rough sea conditions will also aid in dispersal.

Diesel floats quickly to the surface, where it forms a thin sheen that may be increasingly difficult to detect over time, especially when seas are rough.

Diesel can be degraded by naturally occurring marine microbes over a course of months, but is among the most toxic oils to marine life that have direct exposure to it in an undiluted form. Fish, invertebrates and seaweed can all be quickly killed.

According to the US National Oceanic and Atmospheric Administration (NOAA), however, small diesel spills in open water are so rapidly diluted that fish kills have never been reported.

However the NOAA defines a small spill as between about 2,000 and 20,000 liters.

The amount entering the sea off Phuket is reportedly about 40,000 liters.

— Stephen Michael Fein