Water-Quality Inventory Pesticides in the Golden Gate National Recreation Area

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In 1998, all urban creeks in the San Francisco Bay Area were added to the Clean Water Act Section 303d list due to known or suspected diazinon impairment. Diazinon is an organophosphorus insecticide used on lawns, and fruit and vegetables. This pesticide has since been "phased out" and has not been available for purchase since late 2004. Diazinon use is declining and is being replaced by other pesticides such as pyrethroids.

There are currently seven pyrethroid pesticides that are the new focus of the San Francisco Bay Regional Water Quality Control Board's "Water Quality Attainment Strategy" /Total Maximum Daily Load (TMDL) Implementation Strategy for Pesticide-related TMDLs. These pyrethroids include bifenthrin, cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, lambda-cyhalothrin and permethrin. This information is based on urban pesticide market/water quality evaluations indicating that these are of the greatest concern for urban surface water quality.

In the Golden Gate National Recreation Area, there is concern regarding pesticide use within parklands. These pesticides can be harmful to aquatic life including threatened species. Pesticides have been tested in soils, sediments, surface water, and groundwater in some areas within the park through the Presidio remediation program; however, pesticides have not been tested in many surface waters within Golden Gate National Recreation Area. Knowledge of the baseline condition of streams related to pesticides is a critical need for resource management.

Based on the Baseline Water Quality Data Inventory and Analysis Reports required under NPS-75 - Natural Resources Inventory and Monitoring Guideline, the Golden Gate National Recreation Area and Presidio have been targeted to collect "Level 1" water quality data in answer to these concerns.