Pollutants from the Gulf War serve as water mass tracer in the Arabian Sea

In 1995, concentrations of the chlorofluorocarbon compound CFC-12 in the ou tflow water from the Persian Gulf were 8-40 fold higher than normally cause d by air-sea gas exchange. At that time, the anomaly was restricted to the Gulf of Oman north of 20 degrees N, while in 1998 the signal had spread sou thwestward to 12 degrees N. The sources of this CFC-12 input of about 6400 kg are most likely the fire extinguishers and solvents used during and afte r the Gulf War in 1991, This CFC-12 signal is a new feature of the Persian Gulf Water (PGW) which can be used to track and quantify the spreading and dilution of PGW in the northern Indian Ocean. The contaminated PGW spreads southward with a mean velocity of 0.02-0.025 m s(-1). At 20 degrees N, the anomaly is diluted by a factor of more than two, and east of the island Soc otra by a factor of four. A mean transport of less than 0.5.10(6) m(3) s(-1 ) is calculated for PGW assuming a mean dilution rate of 30% from the sourc e signal in the Gulf of Oman to the western Arabian Sea.