HomeMy WebLinkAboutCT 02-16; ROBERTSON RANCH; REVISED MITIGATIVE RECOMMENDATIONS; 2002-10-28REVISED MITIGATIVE RECOMMENDATIONS
FOR REMOVAL AND PLACEMENT OF'
TOXAPHENE AFFECTED SOIL DURING GRADING
ROBERTSON RANCH, PARCEL 1
CITY OF CARLSBAD, SAN DIEGO COUNTY,
CALIFORNIA 92008, DEH FILE NO. H02725-001
FOR
COUNTY OF SAN DIEGO
DEPARTMENT OF ENVIRONMENTAL HEALTH
LAND AND WATER QUALITY DIVISION'
SITE ASSESSMENT AND MITIGATION PROGRAM
P.O. BOX 12961
SAN DIEGO, CALIFORNIA 92112-9261 '
W.0. E3098-3-SC OCTOBER 28, 2002
Geotechnical • Geologic. Environmental
5741 Palmer Way • Carlsbad California 92008 • (760) 438-31.55 • FAX (760) 931-0915 .
October 28, 2002
W.0. E3098-3-SC
County of San Diego
Department of Environmental Health
Land and Water Quality Division
Site Assessment and Mitigation Program
P.O.Box 12961
San Diego, California 92112-9261
Attention Mr. Ewan Moffat, M S D-561
Subject Revised Mitigative Recommendations for Removal and Placement of
Toxaphene Affected Soil During Grading, Robertson Ranch, Parcel 1, City of
Carlsbad, San Diego County, California 92008, APN 168-050-47, DEH
File No H02725-001
Dear Mr. Moffat
Based upon comments and recommendations made by Mr. Ewan Moffat of the' County of.
San Diego Department of Environmental Health (DEH), GeoSoils, Inc. (GSI), has prepared
this revised report for mitigative recommendations for the 'removal and subsequent
placement of toxaphene affected soil during grading on the subject property in the City of
Carlsbad, California. These recommendations are based. upon our knowledge of the
property (GSI; 2002e, 2001c)', our previous agricultural chemical residue surveys (GSI; '
2002a, 2002c, 2001 b), and, conversations with Mr. Ewan Moffat of the (DEH). The purpose '
of this revised report is to provide mitigative recommendations during remedial grading for
the estimated limits of removal and for the location of burial of impacted earth materials at
locations and depths which will effectively eliminate future human contact, as well as
eliminate potential impacts to surface water and groundwater.
Based upon our information provided in the referenced Phase I Environmental Site
Assessment (ESA) report on historical land use (GSI, 2001c), the subject property was
utilized for agricultural purposes from at least 1928 to the present..Based upon our
previous chemical testing of' near surface soils onsite (GSI; 2002a, 2002c, .2001b), '
detectable concentrations of restricted agricultural residues exist within Parcel 1 of
Robertson Ranch.' Concentrations of toxaphene above the Preliminary Remedial Goal.
(PRG) of 0.44 milligrams/kilogram:were encountered ,in locations which are -actively..
ultivated or were in the past and several localized areas Generally, the toxaphene was
encountered within the upper 1/2 to 1 foot of soil GSI (2002a) recommended the following
•••- ' . • ' ' ' ' • ' •
Suruicial soils with concntrations of toxàphene greater tha
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be placed within street areas only, and should be placed belo
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to mitigate the potential for human contact. Soils requiring
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be placed in canyon bottoms or below subdrains, where there. is potential cont
a
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With groundwater. Affected soils should be buried within t
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b
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only, and placed so as not to adversely affect surface water.
,
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of fiioV)äl at the four locatioñs with elevated toxapheii
ie Fë2 f6fñãFAC13S:7ändTY Ffoôt:below existing grade for the eastern portion of the p
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Based upon review of chemical laboratory results from ou
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(GSl; 2002a, 2002c, and 2001 b), G'Sl recommends that t
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• locations are as presented on Plate 1, with the addition of
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ACRS-6 (removals of 1 foot below existing grade). Calculati
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i __•______-----'---..' '-•-,- - - -'__.I, 0 -
indicate approximately 46,000 cubië yards re-'-•-commeridediot-removal
Based upon a review of our previous geóte'chnical evaluatidn of the s
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(
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1" 2002e), 'groundwater was' encountered in exploratory
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proposed College Boulevard at depths ranging from'9 fe
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14 feet bgs. Alluvium in this area consists of clayey sand and
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of 45 feet bgsin the central alluvial valley and approximate
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the alluvial valley. Paleosól soils were encountered ben
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eotechnicalremovals-within.valley'areasareanticipated to
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oto'depths where tu,ratedalluviaLdeposits are encou
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', GSI reviewed grading plans. for College Boulevard,' dated' D
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9 by O'Day Consultants,. Sheets 23 and 24. Between station num
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-• ra6gingfr6T01eet1o35.feIn thickness are proposed fOr t
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Boulvard. isourundFtanding
0 'feet bêlbwsubäe (to allow for the proposed
2oeep sewer and stoñiThrain pipes) and at least 10 feet above groundwater
during heavy, rainfall years). Preliminary calculations indicate thati eii
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-within the site boundary to bury all affected soil. A cro
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•, grade, proposed underground Utilities, existing ground surf
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location of proposed placement of toxaphene affected soil,
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1
1
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+60 College Boulevard is-shown on Figure 1, and the approximate location of the cross
-section • • is shown on Plate 1
,0••0 emovalsand.buriaLshouldbe monitored byareF
IiveofthiToffiE Random sarni should be conducted inatJeast1 8JiTafter removal 'of t
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onsite to evaluate that all affected earth materials have
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:
--concentrations of restricted pesticides are detected above t
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cHected at the removal depth, additional removal
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c ncentrations of earth materials are below PRG criteria
¶ounty of San Diego - - . •, •- • : ' •' W.O. E3098-3-SC Robertson Ranch, Parcel 1, Carlsbad
- , -- - • October 28, 2002 File e \wp7\env\e3000\e3098 3 rmf
.',Page2 - GeoSoils, Inc.
Ox 0 00 •0
Proposed location of 120
- Proposed College Boulevard toxaphene affected soil
EXISTING ProposedGRADE opose er) I PROPOSED
\M~
(IN FEET): 0 0 0
0
Oaf
0 :oal
TD:46V2 0
0 0 0 BEDROCK (Claystoné-paleosol)
120
0 L
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V
-80.
0.
N
(IN FEET)
-40 0
N44E.
At Station 111 + 60 College Boulevard
0 LEGEND •
at Artificial fill 0
Qal Quaternary alluvium
0
------- Approximate location Of geologic contact
Groundwater 0
B-4 Approximate location of exploratory geotechnical
boring by GSI, April 2000 0
0 •• LOS ANGELES CO. 0 RIVERSIDE CO.
ORANGE CO.
. SAN DIEGO CO.
CROSS SECTION X - X'
Figure 1
n. E3098-3-SC flATF 10/02 SCALE 1';40
It is our understanding that ifL sure;L"is needed, a final report of the excavation,
removal, and burial of the affected soils onsite will be required by the DE
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final report would include a sample and burial location map and labo
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.
LIMITATIONS
GSI has performed the services for this project in accordance with the te
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o
f
a
c
o
n
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a
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t
between GSI and Client and in accordance
. with current professional standards for investigations of this type. The conclusions presented in this report ar
e
b
a
s
e
d
o
n
t
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e
information collected during the study, the present understanding of t
h
e
s
i
t
e
.
c
o
n
d
i
t
i
o
n
s
,
and professional judgment
lease note, subsurface and hazardous waste/toxic substance conditio
n
s
m
a
y
v
a
r
y
f
r
o
m
ose provided .in historical documents reviewed by GSI. The interpr
e
t
a
t
i
o
n
s
a
n
d
ecommendations of GSI are based solely on such information and/or. info
r
m
a
t
i
o
n
s
u
p
p
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i
e
d
.
y Client. Findings of this assessment based on data provided by o
t
h
e
r
s
c
a
r
r
i
e
s
n
o
arranty, expressed or implied, as a result of the usage of such data.
It is possible that future assessments may reveal additional data or variat
i
o
n
s
o
f
t
h
e
c
u
r
r
e
n
t
data which may require the current conclusions and recommendations to
b
e
r
e
e
v
a
l
u
a
t
e
d
.
As a result, GSI makes no warranty, either express or implied, as to its fi
n
d
i
n
g
s
,
o
p
i
n
i
o
n
s
,
recommendations, specifications, or professional advice exce
p
t
t
h
a
t
t
h
e
y
w
e
r
e
promulgated after being prepared in accordance with generally accepted stan
d
a
r
d
s
o
f
c
a
r
e
and diligence normally practiced by recognized consulting firms. performi
n
g
s
e
r
v
i
c
e
s
o
f
a
similar nature.
. . . .
The information in this report is relevant to the date of the site work a
n
d
s
h
o
u
l
d
n
o
t
b
e
relied on to represent conditions at any later date. Facts, conditions, and ac
c
e
p
t
a
b
l
e
r
i
s
k
factors change with time, accordingly, this report should be viewed withi
n
t
h
i
s
c
o
n
t
e
x
t
.
)Uflty of San Diego .
. . . . W.O. E3098-3-SC bertson Ranch, Parcel 1, Carlsbad
October 28, 2002 . :e:\wp7\enve3000\e3098-3.rmf
. ..
. . . ., . . Page 4 . GeoSoils, Inc.
The opportunity to be of services is appreciated. If you should have any questions, please
do not hesitate to contact the undersigned at (760) 438-3155.
Respectfully submitted,
GeoSoils, Inc. /. Reviewed by:
/..; .&•
REA 6W10
NO. 1675 cp T. Gooley 4onn~a di 'k ohn rank in Exp. W.
gl REA-1 6400
Yn
-1 1675, CEG 1
DG/JPF/jh
Attachments: Appendix - References
Plate 1 - Agricultural Chemical Residue Survey Sample Location Map
Distribution: (2) Addressee
(3) McMillin Companies, Attention: Mr. Don Mitchell
(1) Job Site Trailer, Attention: Mr. Tom LaMarca
unty of San Diego W.O. E3098-3-SC bertson Ranch, Parcel 1, Carlsbad October 28, 2002 e:\wp7\env\e3000\e3098-3.rmf
: Page 5
GeoSoils, Inc.
APPENDIX
REFERENCES
County of San Diego, Department of Agricultural, Weights & Measures, 2001, Request for
public information number 01 -RP0051, dated October 2.
County of San Diego, Department of Environmental Health, 2002, Voluntary assistance
program, DEH Number H02725-001, Robertson Ranch, Parcel 1, El Camino Real
At Calavera Drive, Carlsbad, dated January 4.
GeoSoils, Inc., .2002a, Agricultural chemical residue survey to delineate limits of soil
removal, Robertson Ranch; parcel 1, city of Carlsbad, San Diego. County, California,
92008, DEH file no. H02725-001, W.O. E3098-3-SC, dated June 28.
2002b, Sampling for toxaphene, Robertson Ranch, Parcel 1, city of Carlsbad, San
Diego County, California 92008, DEH file no. H02725-001, W.O. E3098-3-SC, dated
May 24. S
2002c, Detailed agricultural chemical residue survey, Robertson Ranch, Parcel 1,
city of Carlsbad, San Diego County, California 92008, DEH file no. H02725-001,
W.O. E3098-3-SC, dated April 26.
2002d, Work plan for detailed chemical residue survey, Robertson Ranch Parcel 1,
city of Carlsbad, San Diego County, California 92008, DEH File No. H02725-001,
W.O. E3098-3-SC, dated February 25.
2002e,Geotechnical evaluation of the Robertson Ranch property, city of Carlsbad,
San Diego County, California, W.O. 3098-Al -SC, dated January 29.
2001 a, Request for assistance, Robertson Ranch - Parcel 1, a portion of APN's 168-
040-30, 168-050-17 and 208-010-32, city of Carlsbad, County of San Diego,
California, W.O. E3098-2-SC, dated December 6.
2001 b, Limited agricultural chemical residue survey, Robertson Ranch-Parcel 1, city
of Carlsbad, San Diego• County, California 92008, W.O. E3098-2-SC,
dated December 4.
2001 c, Phase I environmental site assessment, Robertson Ranch - Parcel 1, city of
Carlsbad, San Diego County,. California 92008, W.O. E3098-1-SC, dated August 6.
Smucker, Stanford J.,United States Environmental Protection Agency (USEPA), Region IX,
Region 9 Preliminary Remediation Goals (PRGs). Table 2000 Update,
dated November 1. • • S •
GeoSoils, Inc.