Evaluation and Reporting on Contaminant Hydrogeological
12-12-01
Conditions at the Tajiguas Landfill
Page 15 of 24
results from ground water samples recovered on November 29 and December 1,
1993 as follows:
MW#2, MTBE @ 13 ppb and 1,4-Dichlorobenzene @ 0.9 ppb
MW#4, cis-1,2-Dichloroethene @ 5.6 ppb, 1,2- Dichiorobenzene @ 0.6 ppb,
1,4-Dichlorobenzene @ 3.7 ppb, MTBE @ 25 ppb and Trichioroethene (TCE) was
detected at 0.6 ppb.
No verification as to what point sources of aforementioned contamination in
groundwater has been provided.
(94 Correspondence.tif, Image 1)
A March 21, 1994 internal office memo admits that all of their testing for
chromium had not including the specification of Hexavalent Chromium from total
chromium. Hexavalent chromium had been as high as 0.15 ppm in MW#4 on
January 19, 1991 and as high as high as 0.23 ppm in MW#3 on October 27, 1988.
(94 Correspondence.tif, Images 9, 10 , 2 & 3)
A May 4, 1994, Regional board letter to the County reported the following
chemicals identified in groundwater and stated that this is indicative of a release:
Compound
MW#2 MW#3 MW#4 MW#10
1, 4-Dichlorobenzene
1.3
5.4
Methyl-butyl Ether
9.3
15.0
1, 2-Dichlorobenzene
0.5
cis-1, 2 Dichioroethene
0.5
4.8
Trichioroethane
0.5
Benzene
0.9
Toluene
0.6
No verification as to what point sources of aforementioned contamination in
groundwater has been provided.
(94 Correspondence.tif, Image 7)
A May 20, 1994 Regional board letter to the County stated that the existing
extraction trench was only good for "containing" contamination, but was not
acceptable for corrective action and that since the contaminant releases were
on-going, more aggressive source control efforts are needed.
(94 Correspondence.tif, Images 13 and 14)
In a July 14, 1994 EMCON letter to the its client, the County, they state, “The
