Toxics TMDL

Marina Photo

Marina del Rey Harbor is currently designated as an “impaired” water body on the 303(d) list issued under the 1972 Clean Water Act. The Clean Water Act established regulations and mechanisms to clean up the Nation’s polluted waterways, which included provisions for Total Maximum Daily Loads (TMDLs). A TMDL puts a limit on the amount of pollutant a receiving water body can accept in order to protect its beneficial uses. In the Marina del Rey Harbor, a Toxic Pollutants TMDL was developed by the Los Angeles Regional Water Quality Control Board (Regional Board) to set limits on contaminants entering the harbor water column and sediment.  The contaminants addressed in the Toxic Pollutants TMDL are summarized in the table below.

Media Contaminants
Sediment Copper, lead, zinc, chlordane, PCBs, total DDTs, and p,p’-DDE
Water Column Dissolved copper and PCBs
Fish Tissue Total PCBs

Dissolved copper is a major issue in the Marina del Rey Harbor as well as other marinas along the coast. The leading cause of dissolved copper pollution in marinas is from copper-based antifouling paints. Antifouling paints are used to prevent marine growth on surfaces, particularly boat hulls, yet the majority of these antifouling paints contain copper that leaches into the surrounding water causing pollution issues. The Toxics TMDL regulates the amount of copper going into the harbor.

The TMDL is enforced through the assignment of waste load allocations and load allocations by the Regional Board to different permittees. The permittees named in the TMDL include the County of Los Angeles, the City of Los Angeles, the City of Culver City, as well as the anchorages and boat owners in the Marina del Rey Harbor.

More information on the Marina del Rey Harbor Toxics TMDL can be found on the Regional Board’s website here.

Click here for more information on the TMDL relative to boaters.

Click here for more information on the copper impairment in the harbor.


What is the County of Los Angeles doing to remedy the Copper Issue?

The County is committed to researching alternatives to copper antifouling paints and providing the boating community with useful information for the selection of hull protection products. Since 2017, the County has been particularly focused on studying the effectiveness and economic feasibility of non-biocide hull paints and coatings. Non-biocide hull paints do not contain metals or other toxic chemicals that leach into the water. Using zinc or organic biocide paints (e.g. Econea), which do not contain copper, could also help to reduce copper loading in Marina del Rey Harbor.

Click here for more information on boat hull paints.

The County passed an ordinance that requires in-water hull cleaners to use best management practices (BMPs) for all in-water activities. Using BMPs during in-water hull cleaning has been shown to dramatically reduce contaminant loading of pollutants such as copper to the water column and sediment from boat hull paints.

Click here to read the ordinance.

Click here for more information about In-Water Hull Cleaning BMPs.

An in-water dry docking system works by separating the hull of the boat from the water without lifting the boat out of the water. Unlike a typical ‘wet’ slip liner, an in-water dry dock removes the water from between the boat and liner to keep the hull dry when docked. In-water dry docks are a promising new strategy to reduce copper pollution in marina waters and save boat owners money over the long term, since a boat docked in an in-water dry docking system does not need antifouling hull paint (which typically contains copper or other biocides) or regular hull cleaning.

Click here to read the County’s In-Water Dry Dock Pilot Report.

Click here for an informational flyer on drying docking systems.

Boat lifts are devices used to raise a boat out of the water while it is docked in a slip. They help protect the boat from marine growth, corrosion, and other potential damage, such as electrolysis. The County is investigating the use of boat lifts at Anchorage 47 as a mechanism to reduce copper pollution from antifouling hull paints in the Marina del Rey Harbor.

Click here for an informational flyer on boat lifts.

The County has completed several special studies to better understand the Marina del Rey Harbor physical, chemical and biological processes related to water quality. Additional special studies are planned or in the process of being completed.

Click here for information on the special studies.

Dry Slip Liner PHOTO

In-water dry dock PHOTO

For more information on how to get involved with LA County’s Copper Pollution Reduction Programs click here.

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