By Sally Tobin
A Brief History of Contamination
San Francisco Bay has been immortalized in countless tourist photographs and numerous movies, but it hides a dirty secret: toxic waste. The dumping of contaminated waste has been an accepted practice along the Bay shoreline for more than 200 years. Despite the founding of the Environmental Protection Agency in 1970, and the terrible effects of Love Canal’s contamination on its residents in the late 1970’s, this dangerous practice is still commonplace today.
Thousands of toxic sites have been identified around the Bay Area. Identified sites vary from businesses, such as dry cleaners or machine shops that used solvents, to sites used for disposal of lead batteries, to complex, massively contaminated areas such as the United Heckathorn and Zeneca sites in Richmond, and Bayview-Hunters Point in San Francisco. Businesses and marine facilities were preferentially located along the Bay shoreline, close to rail lines and water transportation. Land was cheap in redlined, minority cities, raising the likelihood that toxic industrial waste would be deposited in environmental justice communities.
Stauffer Chemical Company on what is now the Zeneca site (left, 1948) and Zeneca site aerial view, mid demolition (right, 2005)
As the public began to realize the volume and toxicity of industrial waste nationwide, state agencies and the EPA responded to public concerns by developing standards and methods for cleaning contaminated sites. When national and state agencies began to target contaminated areas, businesses still in operation (or in some cases, the military) were ordered to pay for cleanups.
The standards developed for cleanups were thought to protect communities, as well as clean water and air. Unfortunately, early methods of contamination cleanup, especially along the shoreline, tended to use a procedure called “capping.” First, the area containing contaminated materials would be defined, or in some cases, a pit would be created and the contaminated material would be moved into the pit. Then, a concrete or asphalt “cap” would be installed over the contaminated area. This was thought to protect the public from accidental exposure to the toxic waste. Sometimes monitoring equipment would be installed, or periodic inspections for cracks and vegetation and animal digging would be conducted. Importantly, these capped sites were not lined or sealed on the bottom or the sides.
Enter Sea Level Rise
Sea level rise was not considered at the time that capping became the dominant practice along the shoreline. As our climate is changing, water levels in the Bay are becoming higher and as they continue to rise, they will move further inland and encroach on capped sites once thought to have been safely “cleaned up.” California’s Department of Toxic Substances Control (DTSC) has only recently recognized this imminent threat.
However, the true danger comes from beneath. As sea levels rise, pressure on the heavier salt water near the shoreline increases, and it slips beneath the fresh shallow groundwater, pushing our underground reservoirs upwards. As the groundwater rises, it saturates toxic sites from beneath, and the groundwater spreads into neighboring communities the contaminants that were once thought to be safely stored beneath the cap. It is estimated that contaminants can be carried by groundwater as much as three miles from their source. The spread of contaminants poses significant threats to public health, directly impacting vulnerable populations such as young children, pregnant people and the elderly.
A map displaying contaminated sites around the Bay that would be inundated with 1m sea level rise (open sites are blue dots, closed sites are red dots)
We now find ourselves in a race between the speed at which sea level and groundwater rise is occurring, and the speed at which toxic waste can be removed from Bay shorelines. Removal is an expensive process. There will likely be even more toxic dumps discovered, since development proposals usually trigger testing for contaminants, and systematic searches for contaminated sites are rare.
Several unknowns still exist in this process, such as which sites should be prioritized for cleanups, where contaminated sites are found along the Bay shoreline, and the depths at which groundwater is located beneath the surface. All of these require further research, representing a growing call for additional information. A significant shift in the missions of state agencies, DTSC and the Regional Water Quality Control Board, as well as the US Environmental Protection Agency (EPA) may be required to address this threat.
Addressing the Threat
Sea level rise adaptations are planned measures, ranging from nature-based solutions, such as marshland expansion, to hard infrastructure fixes such as sea walls, designed to shield the shoreline from dangers such as storm surge, high tides, wave action, or rising water levels. Although sea walls and levees may protect the physical shoreline, they fail to stop groundwater rise and mobilization of capped toxic waste from unlined pits.
Currently, the only option for stopping the spread of toxic waste (such as carcinogens, heavy metals, and radioactive materials) is to remove it from the shoreline and transport it to specialized facilities. Building levees and sea walls along sections of the shoreline that have either capped sites or contaminated areas poses a threat to public health.
As sea levels become even higher, they will eventually flush salt water over the tops of contaminated sites along the shoreline and wash toxins into San Francisco Bay. This is already happening at the Zeneca Site in Richmond. The Richmond Shoreline Alliance offers virtual “toxic tours” for those looking to inform themselves about the issues of contamination in the context of sea level rise in the San Francisco Bay.
Another aerial of the Zeneca site (1958) where you can see a plume of toxins leaking into the Bay (the white streaks in the bottom third of the photo)
The Earth has a limited capacity to deal with contamination, but biological systems are so complex that it is impossible to identify a “point of no return” before they collapse. Most scientific indicators suggest that pollution has pushed the Earth into a warming cycle. The days of carefree, “The solution to pollution is dilution,” are gone forever. San Francisco Bay is alive today, and still serves as a cornerstone of our regional economy, supporting the local fishing industry and tourism as well as a stunning array of biodiversity and intricate ecosystems. The risks of turning San Francisco Bay into a stagnant bathtub are too high. The Earth is sending us a message. Are we willing to clean up the residues of our past mistakes and do better in the future?