perchlorate occurrence in ventura and los angeles counties dennis a. dickerson executive officer...

Perchlorate Occurrence in Ventura and Los Angeles Counties

Dennis A. DickersonExecutive Officer

California Regional Water Quality Control Board

Los Angeles Region

Perchlorate Detections

• Since 1997 perchlorate has been increasingly identified in regional groundwater– Occurrence closely associated with defense and

aerospace sites

– Highest levels of contamination most likely from “legacy” sources

• new sources not being created

– In some locations, incidental contamination resulting from other sources cannot be ruled out, e.g., fireworks, road flares, fertilizers

Where do we find the highest concentrations of perchlorate in groundwater?

• Greatest concentrations in groundwater are found closely associated with aerospace and defense sites– Aerojet (Baldwin Park)– JPL (Pasadena)– Santa Susana Field Lab (Boeing)

Significant Source Sites in Ventura County

• Boeing’s Rocketdyne SSFL – Santa Susana Field Lab

• near surface 48 ppb (ES-11)

• Chatsworth 1,600 ppb (HAR-16)

• Off-site 4-5 ppb, single detects not repeated

• San Nicholas Island – US Navy 16 ppb

– Maximum concentrations in groundwater

Other Perchlorate Detections in Ventura County

• Simi Valley– 17 detections in groundwater

• all less than 20 ppb

• 7 of the 17 detections less than 6 ppb

• no definable plume

• at present, no clear connection to SSFL as the source

• Ahmanson Ranch– 28 ppb (MW-1)

• split sample showed non-detect

• pending additional round of sampling

– Maximum concentrations in groundwater

Significant Source Sites in Los Angeles County

• Whittaker Bermite Site

– Santa Clarita - 310,000 ppb

– DTSC Order

• NASA/JPL

– Pasadena - 1,500 ppb

– USEPA Order (Superfund Site)

• Aerojet – Azusa - 2,180 ppb

– Regional Water Board Order

– Maximum concentrations in groundwater

Perchlorate found in Monitoring Wells in Azusa (BPOU)

Perchlorate found in USEPA Multi-port monitoring wells across the Baldwin Park Operable Unit (BPOU) in Azusa, California

Other Perchlorate Detections in Los Angeles County

• Central Basin

– sporadic detections have been reported in Vernon, Commerce, Norwalk and Bellflower.

• San Gabriel Basin

– perchlorate has been detected basin-wide, inside and outside designated Superfund areas.

• Pomona Valley

– the City of Pomona has reported perchlorate detections as high as 19 ppb in 23 production wells.

Perchlorate Impacts

• Ventura County

– No drinking water wells impacted

Perchlorate Impacts

• Los Angeles County

– Numerous drinking water wells impacted (over 130 total)

– Drinking water wells in the Cities of Santa Clarita, Valencia, Saugus and and Newhall have been affected.

– City of Pasadena shut down 9 of their 13 drinking water wells due to perchlorate impact

0 400 800

SCALE IN FEET

ClO4– > 500 ppb

ClO4– > 10 ppb

JPLFacility

JPLFacility

Operable Unit 2

Operable Unit 1:Source RemovalOperable Unit 1:Source Removal

Operable Unit 3:Plume ContainmentOperable Unit 3:Plume Containment

Figure 8

Treatment Options

• Treatment is possible but costly

• Current wellhead treatment systems not designed for perchlorate– retrofits are required

Regional Board ActionsSource Identification Efforts:

1997– Directed the City of El Monte, water supply companies and some dischargers to sample for perchlorate.

Analytical results ranged from 1 to 5 ppb.

1998 - Assisted USEPA with the identification of perchlorate contaminant sources in the Azusa/Baldwin Park Area.

1998 - Assisted USEPA with the revision of the 1994 Record of Decision for the Baldwin Park Operable Unit amended to include perchlorate.

Regional Board ActionsSource Identification Efforts:

1999 - Directed PRPs in El Monte Operable Unit to sample for perchlorate.

2000 - Directed Lockheed (in San Fernando Basin) and NASA/JPL (Raymond Basin) to sample for perchlorate.

2001 - Directed some dischargers in Monrovia and South El Monte to sample for perchlorate.

Regional Board ActionsSource Identification Efforts:

2002 - USEPA and the Regional Board direct PRPs

in South El Monte and Puente Valley Operable Units to sample for perchlorate and other emergent

chemicals.

2002 - Regional Board issues 13267 investigation letters to Boeing (Santa Susana Field Lab) and Ahmanson

2003 - Regional Board staff send out 433 letters to NPDES dischargers requesting a one time sampling for

perchlorate, NDMA, 1,4-dioxane and hexavalent chromium.

Recent Regional Board Actions

• Current focus is on investigation– orders issued to determine extent of

contamination

• Future actions– Cleanup and Abatement Orders where

warranted– increase source identification efforts– work with USEPA on significant sites

Conclusions• A number of distinct and significant sources of

contamination are known.

• Many sources remain to be identified

• Most identified source sites have not yet been remediated.

• The occurrence of perchlorate in groundwater poses a significant additional economic burden to conduct wellhead treatment of drinking water resources.