2515 COLBY AVE 2016-01-01 MF Import

h��A� � t � � 4�� p[.��.��., � _ Ilrl . •. . ... ; � . .. . �� '�. � . �... . � . w•..s �t �✓:- H � �� q� m C M b � N K � ' ` LO]IS Cor�wration WG1049-01-067 o� � ro July 18, 1991 Page 10 � � � ' contained a TPH concentration of 1,200 parts per million (ppm). Soil samples collected at 5.0 o ., feet below grade in borings B-2 and B-3 did not coniain TPH concentrations in ezcess of the 10 � c�a � e ppm detection limit. y On June 13, 1991, seven soil borings (B-101 through B-10'n were drilled in the vicinity of �$ y � boring B-1 in an effort to delineate the soil contamination discovered during the previous field ' �+ � N � work. Three borings(B-102, B-106,B-10'n were drilled in a circulaz array appreximately eight � � r feet from boring B-1. Rorings B-101, B-103, B-104, B-105 were placed in a circulaz array �d � „�, approximately 15 to 20 fect from boring B-1. With the exception of B-101, soil samples were collected from each boring at the surface, 4.0, II , � 5.5, 7.0 and l0A feet below grade. In boring 8-101 soil samples were collected at the surface, � 4.0, 5.5, 7.0, and 8.5 feet below grade. Soil samples were stored in an ice chest at the site and taken to the analytical laborarory for analysis. Soil samples coliected at 4.Q 5.5 and 7A feet , below grade in borings B-102, B-106, and B-107 and at 4.0 and 7A feet in boring B-103 were analyzed by the project laboratory for TPH by L-PA T4ethod 418.1. A review of these results indicates that, with the exception of sam,:.� B-103 at 4.0', no soil sample contained TPH in 3 excess of the 10 ppm detection limit. Sample B-103 at 4.0' contained a TPA concentration of 1,300 ppm. �� � � � B. Discussion The contamination detected in boring II-1 had the cor.sistency of oil and was found in fill soil. 1 ��. � Reportedly, an underground storage tank (US'1� hau been removed from the vicinity of boring �� B-1. It is likely the contamination detected in boring B-1 was the result of(a) spills or lcakage of oil from the former UST or(b) contamina:ed soil backfill placed in the excavation at the time �,� ' the UST was removed. � a ' �� ' It appears that the horizontal extent of TPH contamination detected in boring B-1 is limited to ° the vicinity of the boring as shown by the lack of detectable TPH in borings B-102, B-106, and i'�O ' � B-107. TPH contamination found at 4.0 feet below grade in boring II-103 also had the , � consistency of oii and appeared to be associated with an old surface drain oc sump. The TPH contamivation appears to be limited vertically as no TPH contamination was detected in the soil " sample collected from seven ieet below grade. Although the vertical extent of TPH � �+�� , contamination in boring B-1 was not defined in this study, it is likely that the dense nadve soils i encountered under the fill in boring B-1 has limited the vertical migration of the TPA � � � t contamination. Additionally, no visual evidence of TPH contamination was noted in soil samples � f�` . collected below a depth of 10 feet in boring B-1. � �..�1 :p � I � �.� � ;�� Naldvccr Associates .�