Unlike samples in 2018, taken as part of ongoing investigations into Agent Orange usage on Guam, soil samples taken in October 2019 did not lead to trace detection of chlorinated herbicides, but did detect dioxins. A report detailing the results is recommending that continued investigation take place to clarify any uncertainty about herbicide types, amounts and locations sprayed.
The report was released Monday by the Guam Environmental Protection Agency in response to inquiries from Sen. Therese Terlaje, but is dated March 30. The report was developed by Weston Solutions Inc. under a task order from the U.S. Environmental Protection Agency Region 9 federal on-scene coordinator.
Results from the 2018 sampling indicated the presence of 2,4,5-TP and 2,4,5-T chlorinated herbicides at Tiyan Junction. The 2019 sampling from the area did not detect traces of these compounds, but it did result in toxic equivalency quotient concentrations 1.4 times higher than any other TEQ result.
Moreover, one or more individual dioxin and furan congeners, or substances that are related to each other, were detected in all 10 composite samples, and eight out of the 10 samples had detections of TCDD congener, according to the 2019 sampling report.
The manufacturing process for 2,4,5-T can create 2,3,7,8-TCDD, a type of toxic dioxin. For this reason, herbicide 2,4,5-T was banned in the 1980s.
A Government Accountability Office report noted that draft environmental assessments written in 1999 and 2009 indicated herbicides 2,4-D and 2,4,5-T were used for weed control on Guam through 1980. These herbicides were components of Agent Orange. The report, however, did not find definitive evidence that Agent Orange was offloaded on Guam.