Evaluation of Non-Point Source Runoff on Suspended Solids that Enter Santa Monica Bay

Hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), demonstrate a high affinity for fine particles, the so-called suspended solids or sediments (SS) in natural waters. This study focused on PAHs from the SS collected from non-point source runoff into Santa Monica Bay, California. The runoff came from the urbanized Los Angeles watershed of Ballona Creek, which is approximately 325 square kilometers in size and developed primarily with residential and light commercial industries. In the 1997–98 rain season, an El Nino year, storm events were monitored to show the pattern of non-point source runoff. The primary objective of this study was to determine the types and concentrations of organic pollutants associated with the suspended solid phase. A calculation of the mass of the pollutants for each storm was conducted. Other objectives included 1) to study for the relationship between storm flow and pollutant loading, including the determination of a first flush, 2) to compare concentration of pollutants with an environmental indicator and 3) to do a simple comparison between point source and non-point source sources of pollution.