About This Project

Near-toxic levels of mercury were recently discovered in the fur of mountain lions in the mountains of coastal California. Wet deposition of fog water, which is enriched in mercury, was suspected to be the cause. The foggy coast of California is also a major food growing zone, and we hypothesize that mercury in fog poses a risk to its residents through the diet. We propose to make measurements of mercury in crops and animal products from foggy and non-foggy areas.

Ask the Scientists

What is the context of this research?

Mercury is global pollutant that causes neurotoxicity in humans and wildlife. The international agreement called the Minamata Convention regulates mercury emissions worldwide, and this project will help inform the effectiveness of this international regulation by providing information on key mercury pathways in the environment. Mercury in coastal sea fog is now recognized to be an important pathway for mercury to enter coastal terrestrial food webs. This research will help us understand the risk to humans living in, and consuming food grown and produced fog-zones.

What is the significance of this project?

Mercury bioaccumulates very readily to levels that produce neurotoxicity in many top predators (humans being one of them). Understanding how mercury moves and transforms in the environment is an active area of research. My discovery of methylmercury in coastal sea fog is one such important recent finding. By knowing whether methylmercury in this fog can specifically contaminate crops and animal products from the central California coast, we will ultimately be able to assess the risk to humans to bioaccumulation of mercury due to relying on a diet of foods produced in this and other regions with similar types of fog.

What are the goals of the project?

We will answer the question of whether produce and animal products that humans consume, that was grown or produced on the foggy central coast of California, has elevated mercury levels relative to produce and animal products from non-foggy zones.

The research would start by collecting important food crops from the Santa Cruz, California area at the end of the fog season (September). We will also collect samples of goat and cow milk and meat from animals grazed in this area, in addition to free range chicken eggs from local farms.

We will then analyze these samples for total mercury and of those, we will choose the ones with the highest levels and run those for methylmercury.

We will compare these findings with control samples obtained from the non-foggy regions of California.