Small traces of the toxic chemical dioxin, a carcinogenic that attacks the immune system and can cause reproductive and development problems, have been found at water sources near a U.S military base in North Gyeongsang Province.
Tests conducted on water samples gathered from the area near Camp Carroll in Chilgok showed small traces of dioxin in two to three out of 10 underground water sources and three out of six streams near the base, but no concrete links to the base have yet been proven.
The presence of the agent is a concern as it is occasionally found in the air, soil and streams, but rarely in underground water sources. The government plans to announce the results of its probe on Thursday.
This is the second time that traces of the toxic chemical have been detected in underground water sources near Camp Carroll, following similar tests conducted in late May by a team of experts at Pohang University of Science and Technology (POSTECH) at the request of the provincial government.
"The National Institute of Environmental Research verified the POSTECH analysis and discovered traces that showed the possibility of dioxin in samples of underground water, while samples from nearby streams clearly contained dioxin," a government source said.
The government will downplay the findings in Thursday's report pending further research as the levels detected remained within legal limits, another official said.
"The dioxin discovered in the underground water samples was within the limits set by the U.S. Environmental Protection Agency and our Environment Ministry, so we will announce that no dioxin was discovered," he said.
"But we need to conduct a further investigation into soil samples from Camp Carroll in order to determine whether the dioxin detected in the underground water and streams came from chemicals stored in the base."
However the findings have already set some experts on edge.
"Dioxin that is released from incineration facilities either falls to the ground or gets washed into streams by rain, so it is not that unusual to detect the chemical from such sources," said a chemical-analysis expert familiar with the case.
"But it is extremely rare for dioxin to be detected in underground water sources tens of meters below the surface, no matter how small the amount. There is a strong chance that the soil and underground water at Camp Carroll may be contaminated."