 By examining shallow waters for concentrations of DDT, conventional chlorinated pesticides, PCBs, PAHs, and metals after the hurricane NOAA scientists were able to compare results with the past 20 years of monitoring data from the same area.This consistent and historical record of contaminants from the Mussel Watch program proved effective in analyzing the impacts of Hurricane Katrina.Pathology of parasites in bivalves, using oysters and mussels collected via the Mussel Watch program tissue samples were investigated for parasites.