DPR Monitoring Efforts Within Salt Creek Watershed, Orange
County Robert Budd, PhD January 20 th, 2015
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DPR Monitoring Sites Northern CaliforniaSouthern
California
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Salt Creek Watershed
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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
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Frequency of Detection of Pesticides Monitored Within Salt
Creek Watershed (2008- Present)
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Dash = Mean concentration Dotted = Minimum EPA Aquatic
Benchmark
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Proposed Gauging Station Niguel Road
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Flow Gauging Station Objective: Ability to estimate contaminant
loading within main stem of watershed on annual basis
EventEstimateMeanSDMedian2.5th PCT97.5th PCT Storm Flux
(g/s)3.144.911.680.2115.20 Load (g/yr)1.750.111.751.561.98 Nonstorm
Flux (g/s)1.381.620.890.155.38 Load (g/yr)42.990.2742.9942.4743.54
Example: Fipronil at SC3 (storm drain) Monte Carlo Estimation of
Annual Fipronil Loading Using 2013 Flow Data
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Questions ? http://
www.cdpr.ca.gov/docs/emon/pubs/protocol/study270protocol2014_15.pdf
Sampling protocol for DPR Study Number 270; Ensminger, M. P., R.
Budd, K. C. Kelley, and K.S. Goh. 2013. Pesticide Occurrence and
Aquatic Benchmark Exceedances in Urban Surface Waters and Sediments
in Three Urban Areas of California, USA, 2008-2011. Environ. Monit.
Assess. 185: 3697-3710 Published results through 2011;
