From the USGS:
Scientists at the USGS are tracking mercury pollution in the Bay using remote sensing technology, creating detailed maps to monitor mercury pollution and support wetland restoration in a rapidly changing estuary.
The Remote Sensing of Mercury Pollution in South San Francisco Bay project aims to create maps of multiple chemical forms—or “species”—of mercury across time and space, giving resource managers new tools to monitor water quality, especially after extreme storms. By combining satellite imagery, shipboard radiometry, and in-water sampling, researchers are building a time series of data on mercury species, including methylmercury, a particularly dangerous form that accumulates in fish and other wildlife.
A Legacy of Gold—and Contamination
Mercury pollution in the Bay Area has deep roots. During the California Gold Rush, mercury was used to extract gold from ore, and the runoff from those operations continues to contaminate waterways today. Mercury is also introduced through urban runoff and atmospheric deposition.
Methylmercury is a potent neurotoxin that affects top predators, birds, and even humans who consume fish from the bay. Understanding where and when mercury levels spike is crucial to ecosystem health.
This is especially important as climate-driven storms and floods become more frequent, churning up bottom sediments and releasing previously trapped mercury into the water column.
Wetland Restoration Meets New Technology
At the same time, the Bay is the focus of some of the largest wetland restoration efforts in the country, led by groups like the South Bay Salt Pond Restoration Project. Their work to convert more than 15,000 acres of former salt ponds into healthy tidal wetlands is helping restore habitat and improve water quality—but it also changes how mercury moves through the system.
To help navigate this complex landscape, USGS scientists are turning to a multi-pronged data approach. Satellite-based remote sensing provides broad, repeatable coverage over time, while ship-based radiometers and in-water sensors provide high-resolution information on the physical properties of water. Together, these tools allow researchers to create dynamic maps that reveal how mercury concentrations shift after storms, between tides, and through seasons.
Click here for the USGS project page.
MORE COVERAGE OF MERCURY ON MAVEN’S NOTEBOOK …
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Researchers have found sharp increases in mercury levels in ecologically sensitive areas, including bird flyways in East Asia and North America, as well as Amazonian regions affected by mining and deforestation. By Chloe Baul, Courthouse News Service A Tulane University-led study finds that mercury levels in the world’s rivers have more than doubled since the 1850s, with gold mining, industrial waste, and soil erosion driving a rise that could threaten ecosystems and public health. A study published on Wednesday in […]
USGS: Mapping mercury in San Francisco Bay
From the USGS: Scientists at the USGS are tracking mercury pollution in the Bay using remote sensing technology, creating detailed maps to monitor mercury pollution and support wetland restoration in a rapidly changing estuary. The Remote Sensing of Mercury Pollution in South San Francisco Bay project aims to create maps of multiple chemical forms—or “species”—of mercury across time and space, giving resource managers new tools to monitor water quality, especially after extreme storms. By combining satellite imagery, shipboard radiometry, and […]
USGS: Wildfires increase mercury concentrations in headwater streams
The U.S. Geological Survey is researching the effect of wildfires on the release of stored mercury from forest watersheds and subsequent transport, methylmercury formation, and bioaccumulation post-fire. Wildfires not only alter the re-release of mercury into the environment but also affect its reactivity and availability to the food web, complicating predictions of mercury exposure risks to wildlife and humans amid other co-occurring stressors. Mercury is a toxic heavy metal that poses significant wildlife and human health risks. It is converted […]
USGS: New maps identify legacy mercury contamination in the Sierra Nevada
A series of USGS interactive maps have recently been published. The maps identify locations and levels of mercury contamination resulting from historical gold mining California’s Sierra Nevada. From the USGS: Many may not know that mercury was used by miners during the California Gold Rush to extract gold. Using a process called amalgamation miners would combine mercury with gold ore to form a gold-mercury amalgam. The mercury was then removed by heating. After the mercury had evaporated, pure gold was […]
NOTICE of Document Availability and Staff Workshop: Delta Mercury Control Program Review Staff Report for Scientific Peer Review
From the Central Valley Regional Water Board: The Central Valley Regional Water Quality Control Board (Central Valley Water Board) announces the release of the Delta Mercury Control Program Phase 1 Review of the Sacramento-San Joaquin Delta Estuary Total Maximum Daily Load for Methylmercury Staff Report for Scientific Peer Review (Staff Report). Additionally, Central Valley Water Board staff submitted a request for external scientific peer review of the scientific basis of proposed revisions to the Total Maximum Daily Load of Methylmercury […]
