A Retrospective Pollution History of Southern California

Time series of point and nonpoint source contaminant loading histories and pollution indicator variables were developed for southern California. These included: gross indicators (e.g., population, employment), habitat modifications (e.g., dredging, kelp bed size), nutrient loadings (e.g., N, P, TOC, TSS), and toxicant loadings (e.g., pesticides, PCBs, heavy metals). The reconstruction shows that the majority of contaminant loadings in southern California originate in Los Angeles and Orange counties but that San Diego County is rapidly becoming more prominent in toxic additions to the Southern California Bight. DDT, chlordane, PCBs, lead, and copper are of major interest in terms of the magnitudes of historical loadings to the Bight. Time series development revealed that emissions from the breakdown of products containing heavy metals and from the combustion of fossil fuels is the major source of heavy metals to the Bight. The primary source of nutrients, DDT, and PCBs to the Bight are sewage and industrial outfalls.