Following up on historical accounts of offshore DDT waste disposal, Professor David Valentine and participants in his field studies course surveyed pollution in the sediment of the San Pedro Basin, between Palos Verdes and Catalina Island.  What they uncovered was evidence for an offshore disposal campaign of industrial magnitude, in which chlorinated petrochemical waste was disposed throughout the area in an uncontained fashion and spread at the seafloor following disposal.  The results were recently presented in a briefing to state and federal officials, raising major concerns as described in the front page story by the LA Times.  

You can read the full article here: https://www.latimes.com/environment/story/2023-03-23/scientists-uncover-startling-concentrations-of-pure-ddt-along-seafloor-offA-l-a-coast