Los Angeles Basin Contaminated Sediments Task Force

Summary of Watershed and Source Reduction Committee Meeting
January 27, 1999

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Attendees

Catherine Tyrrell/ Michael Lyons, Los Angeles Regional Water Quality Control Board
Mark Gold/ Mitzy Taggart, Heal the Bay
Lauma Jurkevics, California Coastal Commission
Mitzy Taggart, Heal the Bay
Rick Cameron, Port of Long Beach
Guang-Yu Wang, Santa Monica Bay Restoration Project
Tom Piasky, Los Angeles County Department of Public Works
Gretchen Honan, CH2M-Hill
Ken Schiff, Southern California Coastal Water Research Project

Problem Statement

Michael Lyons presented a more detailed evaluation of the available sediment chemistry data to attempt to identify pollutants of concern to focus upon in each watershed of interest. For Marina Del Rey, lead is a primary pollutant of concern, since high sediment levels were found during 1995 and 1997 monitoring. However, zinc was implicated as an agent responsible for toxicity when SCCWRP conducted sediment TIEs, so this metal should be retained as a pollutant of concern. And, since we do not have that much sediment data, we should not completely dismiss other pollutants at this time (such as DDT and PAHs). For the Los Angeles River Estuary, the contaminants of concern do not appear to have changed between the January 1997 and July 1998 sampling periods. We should focus on lead and zinc, although we cannot ignore the other trace metals, as well as PCBs, DDT and PAHs.

Decision Tree Model for Watershed Assessment

Guang-Yu Wang assembled a flow chart to assist in framing the upcoming study of sediment transport and sources of contaminants in Ballona Creek/Marina del Rey Entrance Channels. The marina could be a source of contaminants, due to boating activities and surrounding land uses (including historical sources of contamination). Ballona Creek could contaminate the Marina del Rey Entrance Channel, as incoming tides may push flows from Ballona in this direction (but probably would not contaminate the marina itself). The Army Corps of Engineers is looking at sediment transport from Marina del Rey and its contribution to shoaling in the entrance channel; we will need an update on this issue. We need to identify general treatment methods (best management practices) and perhaps target specific branches of the watershed where sources exist or target specific pollutants of concern.

Army Corps Scope of Work/Stormwater Scope of Work

Gretchen Honan described the progress on the scope of work for the Ballona Creek study. CH2M-Hill plans to meet with each agency to discuss existing data and create a database summarizing these data. They would like to use the existing model to predict contamination areas. We need the Ballona Report summarizing existing information before we move forward with additional data gathering. For now, we should hold off on field sampling to collect additional data.

Mark Gold discussed the stormwater monitoring program. PAHs were eliminated from Los Angeles County Department of Public Works monitoring because they were not detected on several sampling occasions (however, the County is planning to resume PAH sampling for particulates). We need to conduct TIEs to identify the problem constituents in the sediments (i.e., pollutants of concern). Perhaps this could be accomplished as a special project using funds from the City of Los Angeles’ settlement. We need to determine appropriate detection limits for various constituents; perhaps we can use those selected for the Bight’98 regional monitoring program – Michael Lyons will look into this. We need to ensure coordination of different monitoring program approaches – Ken Schiff will look into the comparability factor.


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