What is a Brownfield?

According to the EPA, Brownfields are defined as “… real property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of hazardous substances, pollutants, contaminants, controlled substances, petroleum or petroleum products, or is mine-scarred land,” according to the Small Business Liability Relief and Brownfields Revitalization Act of 2002.

H.R. 2869 — 107th Congress: Small Business Liability Relief and Brownfields Revitalization Act , Title 2. § 211 (2002).

  • Explore our GIS tool!

    Aerial photo of Lake Berryessa after a storm carrying mercury-laden sediment
  • hydraulic-mining
    Hydraulic mining in the Sierra Nevada was the first large-scale use of mercury mine in the Coast Range (Yuba County, 1870)
  • Corona-Mine
    Corona Mine structures portray the 100+ years legacy of mercury mining

Because of the challenges caused by brownfield contaminants, the federal government established a program in 2002 to help local communities assess and clean up brownfield sites. The US EPA Brownfields Program provides funding, technical assistance, and protection from liability for brownfields projects.

Brownfields caused by legacy mining are called “mine scars.” Mine-scarred lands continue to pose environmental and safety hazards today—both on-site and downstream:

  • As soils erode through natural watershed processes, toxic chemicals are released into local waterways.
  • Wind erosion causes atmospheric dust—laden with contaminants—to fall to the ground.
  • Mineral springs discharge contaminated water.
  • Underground mine tunnels drain groundwater.

Pollutants on Mine-Scarred Lands Affect Everyone

mercury cycling schematic
Click for larger image

Exposure to hazardous materials from contaminated water bodies can harm both human and wildlife health. In particular, methylmercury is easily absorbed at unsafe levels. Methylmercury is readily absorbed from water and food, becoming increasingly concentrated as you move up the food chain. This process is called “bioaccumulation.”

Concentrations of methylmercury in predatory fish (such as bass) and fish-eating wildlife (such as terns and eagles) can increase one million-fold through bioaccumulation. In humans, concentrated mercury in the bloodstream is linked to nervous system and kidney damage [US Department of Health and Human Services, Agency for Toxic Substances and Disease Registry. Division of Toxicology. Public Health Statement Mercury CAS#: 7439-97-6.1999]. It poses the greatest risk to children and pregnant women due to their sensitivity to mercury exposure.

Water that drains from abandoned mines can be highly acidic, harming local waterways. Acidic mine drainage stresses plants and animals, alters chemical properties and natural reactions, and quickly dissolves metals. Some metals, such as nickel, are directly toxic to organisms.

Our Westside Brownfields Coalition Assessment Project has developed an area-wide plan for cleaning up mine-scarred brownfields

While cleaning up mine-scarred brownfields is incredibly important, it is also quite challenging. Various federal, state, and local land management agencies are tasked with cleaning up brownfield sites on public lands. But few incentives exist for voluntary cleanup of contaminated sites on private lands. Furthermore, regulations guiding assessment and cleanup requirements are often inconsistent, unclear, and unenforceable.

The Westside Sac IRWM Coordinating Committee received a grant under the U.S. Environmental Protection Agency (EPA) Brownfields Assessment Program to evaluate mine-scarred lands within the watershed and create an area-wide plan for mine-scarred brownfield cleanup. The implementation schedule was as follows:

Reducing contamination from our community’s mine-scarred lands requires site-specific solutions. Each site has its own unique set of conditions, land ownership, and available resources. The Brownfields Project Team has assessed all the mine-scarred brownfield sites within the watershed, and will continue to evaluate them for potential cleanup based on a suite of relevant criteria.

Project Team Contacts

  • Solano County Water Agency
    Chris Lee, Project Lead (clee@scwa2.com, 707-455-1105)
  • McCord Environmental, Inc.
    Stephen McCord, Project Manager (sam@mccenv.com, 530-220-3165)
  • Local Government Commission
    Danielle Dolan, Facilitator (ddolan@lgc.org, 916-448-1198 ext. 311)