No significant levels of mercury have been found in water sources near the 304 Industrial Park in Prachin Buri's Si Maha Phot district, the Pollution Control Department (PCD) says.
PCD officials last week collected nine samples of sediment and soil and 11 samples of water from the Shalongwaeng canal, which is connected to the industrial site, for testing.
Initial results found the levels of mercury in all samples were acceptable, said a source involved in the testing.
PCD chief Wichien Jungrungruang, however, refused to confirm the results, saying he needed more time to verify the findings before making them public.
"I'd like to thoroughly check the results and prepare an explanation for the public in case the PCD findings are opposite to the environmental group's," he said.
Mr Wichien was referring to the Ecological Alert and Recovery Thailand's (Earth) report released earlier this month which stated that the levels of mercury found in water and aquatic animal samples collected from canals near the estate were unusually high.