USC Wrigley Institute faculty and researchers, with support from the USC Sea Grant program, recently evaluated metal pollutants in Southern California’s coastal waters. By doing so, they provided a glimpse into the impacts of nationwide environmental regulations on the region’s ocean health.
Urban coastal waters are constantly at contamination risk due to high levels of human activity. Wastewater treatment, industrial and agricultural runoff and shoreline activities all add contaminants such as toxic metals into marine systems and food webs. To curb this input, the Clean Water Act and other federal regulations were implemented in the 1970s. But little research has been done to determine whether these policies actually influenced Southern California’s ocean environment.
In a survey of 30 sites across the Los Angeles coastline, USC Wrigley Institute researchers tested human-sourced metal contamination in nearshore waters. Comparing these values to measurements from the 1970s, they found that concentrations of copper, cadmium and other toxins have indeed gone down over time. Southern California’s wastewater, more than 4 billion gallons per day, is treated and released into the ocean 5 miles offshore. The results found by the USC team suggest that the Clean Water Act’s regulation of sewage treatment likely played a significant role in improving our region’s water quality.
Remarkably, these improvements have occurred despite the fact that Southern California’s population increased over the last 40 years. According to the research team, metal concentrations in the region’s coastal waters are now comparable to more pristine and remote sites off of Baja, California. The study has revealed the importance of environmental policies to protect our natural resources and also the need for regular environmental monitoring, particularly in urban coastal areas such as those in Southern California.