I lived in Ocean Springs for awhile - quiet little community before the Casinos came in.
I don't doubt there are some long term lingering effects of that disaster. My sister-n-law works is a biologists that is hired to take bacteria and contamination water samples along the gulf.
4 years ago or so she was telling me her samples were still showing high levels of contaminant in the gulf , especially in the areas where there was vegetation. 4 years is a long time though I guess, I haven't talked to her lately about it.