DPR Monitoring Efforts Within Salt Creek Watershed, Orange County Robert Budd, PhD January 20 th, 2015

DPR Monitoring Sites Northern CaliforniaSouthern California

Salt Creek Watershed

Prioritization Model Based on use and available toxicity data Used to prioritize pesticides for monitoring purposes DPR Urban Monitoring Program – Salt Creek Sampling Protocol 2008 – Present Sampling 4 events/year: 2 dry and 2 storms 8 sampling sites; 4 upper watershed storm drains 3 lower watershed receiving waters 1 treatment facility outfall 173 water samples, 72 pesticides monitored Concentrations compared to aquatic benchmarks set by US EPA

Frequency of Detection of Pesticides Monitored Within Salt Creek Watershed (2008- Present)

Dash = Mean concentration Dotted = Minimum EPA Aquatic Benchmark

Proposed Gauging Station Niguel Road

Flow Gauging Station Objective: Ability to estimate contaminant loading within main stem of watershed on annual basis EventEstimateMeanSDMedian2.5th PCT97.5th PCT Storm Flux (µg/s) Load (g/yr) Nonstorm Flux (µg/s) Load (g/yr) Example: Fipronil at SC3 (storm drain) Monte Carlo Estimation of Annual Fipronil Loading Using 2013 Flow Data

Questions ? Sampling protocol for DPR Study Number 270; Ensminger, M. P., R. Budd, K. C. Kelley, and K.S. Goh Pesticide Occurrence and Aquatic Benchmark Exceedances in Urban Surface Waters and Sediments in Three Urban Areas of California, USA, Environ. Monit. Assess. 185: Published results through 2011;