Welcome to the Calleguas Creek Watershed

Historic Pesticides and PCBs

Various reaches within the Watershed are listed on the California 2002 Clean Water Act (CWA) Section 303(d) list of water quality limited segments as impaired due to various historic pesticides and PCBs. The goal of the Historic Pesticides & PCBs Work Plan is to identify the tasks required to address the beneficial use impairments caused by the pesticides and PCBs of concern for the CCW.

Historic pesticides, such as DDT and chlordane, and PCBs are challenging pollutants to address. In one sense, the ultimate control strategy, banning the use of the pollutant, has already been implemented. However, because of the long-lasting impact of these pollutants in sediment, fish tissue, and the water column, impairments still exist even though many of the pollutants have not been used in the Watershed for over 20 years.

The strategy outlined in this work plan contains three components. One component is an assessment of existing data in the watershed to determine if additional monitoring is needed to develop a TMDL. The second component is an impairment assessment to review standards and beneficial uses to ensure that the impairments are being addressed. The third component is the development of a TMDL to address the pollutants. The three elements of the strategy will be pursued in parallel in order to accelerate the process and satisfy the time constraints of the Consent Decree.

Responsible Agencies

The complete accounting of the responsible agencies and parties to carryout the Historic Pesticides and PCB Work Plan has not yet been formalized, however the Flood Protection and Sediment Management Subcommittee is taking responsibility for providing policy guidance to the technical consultant. An MOU similar to the Salts Work Plan MOU will eventually be developed to formalize the funding of the Historic Pesticides and PCB Work Plan.

Existing Data Review and Monitoring

The quality and quantity of existing water, sediment and fish tissue data will be assessed to evaluate current listings and to develop and implement a monitoring and source identification/assessment plan, if necessary. These data will be evaluated to determine if water quality, fish tissue, or sediment data meet existing standards and the criteria for the LARWQCB to consider delisting or if the listings were based on erroneous listing criteria.

Impairment Assessment Study

An impairment assessment study will be conducted to address the complex interactions between sediment, water column, and fish tissue concentrations and the impacts of these interactions. The Impairment Assessment Study will encompass a comprehensive review of standards and beneficial uses as well as potential beneficial use impairments and overall ecological impacts, including impairments in the water column, sediment, fish tissue and other wildlife, and associated risks to aquatic life and human health. This work may include a multi-lingual fishing / fish consumption survey to determine actual fish consumption patterns in the watershed. In addition, efforts will be made to enlist the aid of social justice and community organizations that might have better access to under-represented populations that fish in the watershed. Results of this study will be used to assess human health / wildlife risks from fish tissue contamination. If applicable, additional studies will be conducted to develop site-specific objectives protective of aquatic life and human health.

TMDL Development

A TMDL for historic pesticides and PCBs will be developed as part of this work plan and work on the TMDL will begin in conjunction with the work discussed above. Because of the complex nature of these pollutants, the work completed in the early phases of this work plan will be crucial in developing scientifically sound and defensible TMDLs that address all of the impairments caused by historic pesticides and PCBs. As part of the TMDL development process, the natural rate at which these pesticides will be removed from the watershed will be assessed and options for preventing transport of contaminated sediments to affected waterbodies will be evaluated.

Early Actions Items to Address Historic Pesticide/PCB Related WQ impairments

Early Action Items will focus on identifying controllable sources, including determining if active sources exist, and developing a plan to address/control these sources. Because unused quantities of organochlorine pesticides are potentially present in households and agricultural areas in the watershed, a public education program will be conducted to educate the public regarding bans and hazards associated with pesticide use.

Timing

The timing of the completion of the various tasks outlined in this work plan is contained in the work plan time schedule summary. The Historic Pesticides & PCBs TMDL Work Plan is to be completed by November 2005 to meet the Consent Decree deadline of March 22, 2006.

Historic Pesticides and PCBs

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