Document k9B1BNweGrRxrJ12M4wVOrrxO

g.rr 4 V SAMPLING TRIP REPORT MONSANTO CORPORATION INDIAN ORCHARD PLANT SPRINGFIELD, MASSACHUSETTS JULY 1988 NOTICE The information in this document has been funded by the United States Environmental Protection Agency (U.S. EPA) under REM III Contract No. 68*01-7250 to Ebasco Services Incorporated (EBASCO). This document has been formally released by EBASCO to the U.S. EPA. This document does not represent, however, the U.S. EPA position or policy and has not been formally released by the U.S. EPA. A complete list of the target compounds analyzed for is presented in Appendix A. The analytical results of all samples for contaminants above detection levels are presented in Table 1. The results indicate the level of vinjrl chloride (20 ug/1) in MW-58 exceed by 10 fold, the araETenE water quality criteria for "the protection of human health (2 ug/1). This is the only well in which this compound was detected. The presence of this contaminant in an area which does not contain known disposal <>**.a ^ the presence of contaminant.) The concentration of benzene exceeded maximum contaminant^level (5 ug/1) in eight wells while bis (2-ethyl hexyl) phthalate was exceeded in six wells. ~fEe" results also indicate that chlorobenzene 'ex"cfeeded the recommended maximum contaminant level (60 ug/1) in seven wells. Additionally, low levels of total xylenes were detected in three downgradient wells. A review of the results of samples taken in monitoring wells upstream of the SWMUs and those taken downstream of the SWMUs revealed some groundwater contamination relative to the parameters used for comparison. Chlorobenzene was detected during the August 1987 sampling trip at less than 0.1 mg/1 in MW-53D but was detected during the February, id68 trip at 3.7 mg/1. This concentration compares with concentrations in the region of 2.5 mg/1 detected in this well during past sampling events performed by the facility's consultants. 4.0 SUMMARY Upon review of the compiled analytical data, some con clusions can be drawn concerning the horizontal extent of a potential contaminant plume at the facility. It has become apparant that downgradient monitoring wells 26S, 25D, 12S and 3IS are contaminated with some volatile and extractable organics. ^ The organics of most concern are benzene, chlorobenzene, bis (2-ethyl hexyl) phthalate, bis (2-chloroethyl) ether and total xylenes .v It is also apparant that wells, 58 and 49 are contaminated to a much lesser degree than 26S, 25D, 12S and 3IS. Well 4S does not show any contamination. These three observations seem to indicate a potential contaminant plume as being localized to the hydraulically downgradient edge of SWMUs in the _ .southern portion of the~Taclity. In reviewing the data, it is also apparant that both shallow and deep groundwater degradation may have occurred. HICOPE; RIVES ortf O l SCALE 490' DATE JULY, 1988 MONSANTO CORP. INOIAN ORCHARD PLANT GROUNDWATER MONITORING WELL LOCATIONS SOURCE2 BLAS LAND & BOUCK ENGINEERS, P. C., MARCH , 1987 4 *3 ir*.il . U l1 M? 6