Title

Aftermath of sulfur mining: The fate of toxins in a watershed in Oakland, Ca

Poster Number

31

Lead Author Major

Geology

Format

Poster Presentation

Faculty Mentor Name

Laura Rademacher

Faculty Mentor Department

Earth & Environmental Sciences

Abstract/Artist Statement

The purpose of this research is to understand whether small, upstream, urban reservoirs act as sources and/or sinks for contaminants. The Lion Creek watershed in Oakland, CA, includes three tributaries, which merge into Lion Creek and then discharge into Lake Aliso. One of the tributaries drains a former sulfur mine and produces acid mine drainage (AMD). Currently, Lake Aliso alternates between full (summer) and empty (winter) seasonally. Water samples were collected from all three tributaries and the inlet and outlet of Lake Aliso. The geochemistry of each tributary and the lake inlet and outlet were measured to understand the cycling of contaminants through Lion Creek watershed.Results suggest that AMD causes elevated conductivity and sulfate and low pH in the tributary that drains the former sulfur mine. Tributary mixing dilutes water from the sulfur mine, decreasing the conductivity and sulfate and increasing the pH. However, not all changes in water chemistry can be explained by simple dilution and mixing; other factors have to be considered, such as the impact of microorganisms and storage of chemicals in the sediment. In addition, water quality at the lake inlet and outlet differ significantly when the lake is full suggesting Lake Aliso may act as a sink for contaminants. Alternating oxic and anoxic laminations in preliminary sediment cores also suggest periodic changes in the nature of lake geochemical cycling. Results from ongoing research will expand our knowledge of biogeochemical cycling in the watershed and provide a scientific foundation for sound water management plans.

Location

DeRosa University Center, Ballroom

Start Date

21-4-2011 6:00 PM

End Date

21-4-2011 8:00 PM

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Apr 21st, 6:00 PM Apr 21st, 8:00 PM

Aftermath of sulfur mining: The fate of toxins in a watershed in Oakland, Ca

DeRosa University Center, Ballroom

The purpose of this research is to understand whether small, upstream, urban reservoirs act as sources and/or sinks for contaminants. The Lion Creek watershed in Oakland, CA, includes three tributaries, which merge into Lion Creek and then discharge into Lake Aliso. One of the tributaries drains a former sulfur mine and produces acid mine drainage (AMD). Currently, Lake Aliso alternates between full (summer) and empty (winter) seasonally. Water samples were collected from all three tributaries and the inlet and outlet of Lake Aliso. The geochemistry of each tributary and the lake inlet and outlet were measured to understand the cycling of contaminants through Lion Creek watershed.Results suggest that AMD causes elevated conductivity and sulfate and low pH in the tributary that drains the former sulfur mine. Tributary mixing dilutes water from the sulfur mine, decreasing the conductivity and sulfate and increasing the pH. However, not all changes in water chemistry can be explained by simple dilution and mixing; other factors have to be considered, such as the impact of microorganisms and storage of chemicals in the sediment. In addition, water quality at the lake inlet and outlet differ significantly when the lake is full suggesting Lake Aliso may act as a sink for contaminants. Alternating oxic and anoxic laminations in preliminary sediment cores also suggest periodic changes in the nature of lake geochemical cycling. Results from ongoing research will expand our knowledge of biogeochemical cycling in the watershed and provide a scientific foundation for sound water management plans.