Discovering DDT: How GCxGC is uncovering an environmental disaster

For years, environmentalists have known about the contamination of DDT in the ocean waters off the California coast. Montrose Chemical Corporation, the largest producer of DDT in the United States from 1947 until 1982, was infamously dumping chemical waste from their manufacturing process into the sewer system, contaminating the Palos Verde Shelf and eventually requiring the area to be designated as a Superfund site in an attempt to clean up the environmental damage. However, the known DDT contamination did not seem to be enough to explain the abnormally high cancer rates in the local sea lions.

Chasing a hunch, David Valentine, a professor of geochemistry and microbiology at UC Santa Barbara, dove deeper.

Ten years ago, Valentine had been following up on rumors of Montrose dumping chemicals in barrels into the Pacific Ocean, away from what is now the Superfund site. He had access to some borrowed equipment and dove 3,000 feet down, 10 miles out from shore. What he uncovered was horrific.

A ruptured barrel on the ocean floorBarrels. Hundreds and hundreds of barrels, some seemingly intentionally punctured (which would match archival testimonial and photographs also discovered). The rumors were real.

Over the next ten years, Valentine and his colleagues returned to the site, running tests on samples taken from various areas. While the contamination is currently in a „deep freeze,” due to the depth and relative lack of oxygen, the location is hardly contained, and punctured barrels would have spilled their contents on their way down to the ocean floor. In at least one spot tested, DDT contamination was found to be 40 times higher than the highest surface level recorded at the Superfund site.

Despite Valentine’s best efforts, there was little movement from any group that might be able to help address this environmental disaster. Now, however, that might be changing.

In March of 2019, Valentine and his colleagues published a paper in the ACS publication Environmental Science & Technology discussing the „sloppy” dumping, including detailed chromatograms using LECO’s Pegasus® GC-HRT 4D’s analysis capabilities to explain the identification and „fingerprinting” of the contamination, tracing the source back to the barrels themselves and not the sewer run-off that had affected the Palos Verde Shelf. In 2020, the LA Times ran an article discussing the history of this investigation.

In 2021, CBS took notice:


As more and more news organizations are picking up this story, it is another reminder of how our actions today can affect our futures tomorrow, whether it be for the worse, such as improper chemical disposal, or for the better, such as using the best tools to discover problems and work to fix them.

Read David Valentine's Paper