L.A.'s coast was once a DDT dumping ground (2020)
latimes.com
latimes.com
Not sure the DDT ranks that high of concern.
If you're looking to spend limited resources addressing it, spending it on the worse situation is just smart.
The studies linking aquatic harm are actually better than the studies linking terrestrial or avian harm. As it's poorly soluble in water it just sorta hangs around and kills fish. This was known all the way back in the 1940's https://spo.nmfs.noaa.gov/sites/default/files/legacy-pdfs/CI...