1. Perchlorate Occurrence in Ventura and Los Angeles Counties
Dennis A. Dickerson
Executive Officer
California Regional Water Quality Control Board
Los Angeles Region

2. 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

3. 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)

4. 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

5. 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

7. 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

8. Perchlorate found in Monitoring Wells in Azusa (BPOU)

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

10. 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.

11. Perchlorate Impacts
Ventura County
No drinking water wells impacted

12. 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

14. JPL Facility Operable Unit 2
Source Removal
JPL
Facility
Operable Unit 2
400
800
SCALE IN FEET
Operable Unit 3:
Plume Containment
ClO4– > 500 ppb
ClO4– > 10 ppb
Figure 8

15. Treatment Options Treatment is possible but costly
Current wellhead treatment systems not designed for perchlorate
retrofits are required

16. Regional Board Actions
Source 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.
Assisted USEPA with the identification of perchlorate contaminant sources in the Azusa/Baldwin Park Area.
Assisted USEPA with the revision of the 1994 Record of Decision for the Baldwin Park Operable Unit amended to include perchlorate.

17. Regional Board Actions
Source Identification Efforts:
Directed PRPs in El Monte Operable Unit to sample for perchlorate.
Directed Lockheed (in San Fernando Basin) and NASA/JPL (Raymond Basin) to sample for perchlorate.
Directed some dischargers in Monrovia and South El Monte to sample for perchlorate.

18. Regional Board Actions
Source Identification Efforts:
USEPA and the Regional Board direct PRPs
in South El Monte and Puente Valley Operable Units to sample for perchlorate and other emergent chemicals.
Regional Board issues investigation letters to Boeing (Santa Susana Field Lab) and Ahmanson
Regional Board staff send out 433 letters to NPDES dischargers requesting a one time sampling for perchlorate, NDMA, 1,4-dioxane and hexavalent chromium.

19. 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

20. 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.