Decades after the Montrose Chemical Corporation dumped the notorious pesticide DDT off Southern California's coast, Scripps Institution of Oceanography at UC San Diego has unleashed findings showing the chemical's lasting imprint on the sea's sediment and aquatic inhabitants. In a study cited by Scripps last Monday, researchers found that, despite DDT's ban in 1972, its residues continue to tarnish fish and ocean floors near the historic dumping zones.

Compiling data from nine datasets from institutions like the Southern California Bight Regional Monitoring Program and the Coastal Fish Contamination Program, the research shows that DDT concentrations are notably higher near known dumpsites. However, the connection between sediment contamination and their piscatorial neighbors isn't uniform—it varies by the fish's diet, habitat, and where they swim. "I was surprised by how strong the relationship was," Lillian McGill, lead study author and a postdoctoral researcher stated, as per Scripps, "strong enough to reasonably predict DDT concentrations in a fish based on where it was caught and its diet and habitat."

Suitable news surfaces, as the findings suggest a downtrend in the contamination's presence in fish over time, with most recreationally caught fish remaining within California's safe consumption limits. But there's a catch—bottom-dwellers like Halibut, fished near the most tainted sites, can still be problematic, and anglers are advised to stay informed through updated consumption advisories.

Brice Semmens, a Scripps Oceanography marine biologist and co-author of the study, suggests that time is slowly interring the offending sediments under newer layers, which may account for the decrease in DDT levels. Yet, not all areas are covered by the study's scope. It's primarily nearshore, leaving the deep dumpsites discovered in 2020 an ongoing concern. "It remains to be seen whether DDT from these deep dumping sites is more problematic than what our results reflect," Semmens stated, as Scripps detailed.

Scripps researchers aren't stopping here—they're already partnering with UC Santa Barbara's Environmental Data Science students to craft SaferSeafood. This website aims to aid anglers in gauging expected contamination in their catch. With a beta version, this tool seeks to enhance the precision of consumption advisories, a potential boon for communities relying on fishing for sustenance.