Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used to assess the
impact of metal pollution on Porites skeletons taken from the Gulf of Thailand since the 1980s. The collection
period coincided with a series of laws enacted by the Thai government to curb environmental pollution.
The extent of metal pollution by riverine input, including aerosol deposits, was assessed by
comparing the metal/Ca (Me/Ca) ratios in the Thai corals to the ratios of another colony of corals sampled
from Rukan-sho, a relatively unpolluted coral reef located in Okinawa, Japan. In this comparison, high riverine
inputs of Ba, V, Cd and Pb were observed in the Thai coral samples. Higher V/Ca ratios found in the
Thai corals compared to the Rukan-sho coral suggest anthropogenic V inputs due to fuel oil pollution in
the Gulf since the late 1990s. The levels of Cd in the coral suggest a gradual decrease in the Gulf in the late
1990s, with a drastic drop in concentration from the 1980s. The historical variation in Pb/Ca ratios
recorded in the coral skeletons suggests that exposure to anthropogenic Pb was a result of discharge from
urbanized areas from 1984 to 1998, which has been gradually reduced since Thailand prohibited the use
of leaded gasoline in the late 1990s.