Effects of the 2003 Cedar and 2007 Witch Creek Wildfires on metal loads in sediment and water from the burned watersheds

Fire is an important disturbance mechanism in southern California’s scrubland and forest ecosystems. However, humans have altered natural fire regimes. The frequency and intensity of fires has been increasing over the last 20 years, and this trend is expected to continue increasing as a result of climate change. Recent studies have found an increase in heavy metal concentrations from the burning of organic material following wildfires. High concentrations of heavy metals can cause severe health problems in humans. Sediment samples were taken before, during and after the rainy season from thirty sites in three watersheds throughout San Diego County. Samples were analyzed for heavy metal concentrations to measure a possible wildfire signature. No wildfire signature was found three years after the most recent wildfire. As a result, sampling should ideally begin immediately following a wildfire. The second part of this study conducted a study which measured southern California resident’s knowledge on the long term effects of wildfires such as heavy metal contamination. Respondents were aware of the recent increase of wildfires and the expected continuing trend. Respondents were also aware of the possible release of contaminants into the environment from the burning of home material. However, respondents were unaware of the possible release of contaminants from the burning of organic material. Residents should be educated on this issue especially residents in remote locations where the probability of a wildfire occurring is high