Rainfall and over- irrigation create runoff that can wash pesticides from landscaped areas and areas around buildings into storm drains and eventually into creeks, bays, and the ocean. In the 1990s, water from San Francisco Bay Area urban creeks proved toxic to aquatic organisms at the base of the food web, primarily due to runoff of the common insecticide diazinon. Diazinon was used throughout the Bay Area to manage many pests, including ants and grubs. The Diazinon and Pesticide-Related Toxicity in Urban Creeks TMDL plan (2007) sets forth actions designed to restore water quality.
By 2005, the Environmental Protection Agency required most products containing diazinon to be removed from retail store shelves. However, other pesticides with equal or greater aquatic toxicity have replaced diazinon and other banned chemicals in the marketplace. Therefore, the TMDL plan addresses pesticide-related aquatic toxicity in general, regardless of which pesticide causes the toxicity.
To comply with required TMDL actions, Marin’s cities, towns, and the County of Marin implement pesticide-related toxicity control programs. Each municipality adopted an Integrated Pest Management (IPM) policy or ordinance. IPM policies and ordinances require staff training and protocols and practices that result in less toxic pest management at municipally-owned and operated facilities.
As part of the education and outreach requirements, MCSTOPPP partners with other state and regional programs to promote pesticide reduction and the use less toxic alternatives.