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DIVISION OF ENVIRONMENTAL PROTECTION T3D (8OO) T77-«4I3 GOVERNMENT OF THE VIRGIN ISLANDS OF THE UNITED STATES ———0——— DEPARTMENT OF PLANNING AND NATURAL RESOURCES NISKY SHOPPING CENTER SUITE 45 CHARLOTTE AM A LIE, ST. THOMAS. V.I. OO8O2 March 6, 1995 x Mr. Thomas Danahy Geraghty & Miller, Inc. 201 W. Passaic Street 3rd Floor Rochelle Park, NJ 07662 Dear Mr. Danahy: This letter is in response to your February 24, 1995 letter requesting the U.S. Virgin Islands Department of Planning and Natural Resources' (DPNR's) approval of Geraghty & Miller, Inc.'s waste characterization of drill cuttings generated during the Phase II Remedial Investigation (RI) at the Tutu Aquifer Superfund Site in St. Thomas. This waste characterization will be used to determine disposal options for the soil, and rock drill cuttings currently stored in sixty (60) drums at the Tracy Dodd property in the Tutu valley. Based on this classification, Geraghty & Miller, Inc. has proposed to dispose of the drill cuttings at the Bovoni Dump in St. Thomas. According to the February 24, 1995 letter, Geraghty & Miller, Inc. collected two (2) composite samples from the sixty (60) drums and performed the Toxicity Characteristic Leachate Procedure (TCLP) and Resource Conservation and Recovery Act (RCRA) testing for ignitability, corrosivity and toxicity on the samples. Geraghty & Miller, Tnc followed a New Jersey waste classification methodology to determine both the frequency and nature of the sampling. However, the procedures outlined in the February 24, 1995 letter for waste characterization of soils and rock cuttings generated during drilling at the Tutu Wellfield Site are not acceptable to DPNR and will not be sufficient for DPNR to approve disposal of Superfund waste material at the Bovoni dump in the future. DPNR believes that the sampling scheme utilized will not adequately characterize any potential hazardous soil waste streams. However, based on the concentrations of total organic chemicals detected in the soils during well drilling, it appears that the material in the drums in question could not generate an unacceptable hazardous leachate and will not pose an unacceptable risk to human health through TUT OO6 0462 *64598* 64598 the ingestion or inhalation pathways. As a result, DPNR approves the disposal of these sixty (60) drums of drill cuttings at the Bovoni Dump. Future waste characterization sampling must provide a more accurate representation of the waste stream. For example, in the sampling of the phase II RI drill cuttings, materials from "hot" areas were mixed in drums with materials from uncontaminated areas. Under the sampling scheme utilized, it could not be adequately determined whether drums that contained the more grossly contaminated soils were properly sampled. The sampling frequency of two (2) samples per thirty (30) drums is not representative of a potential waste stream at this site and, as a result, not acceptable. At least ten (10%) of the drums must be sampled, particularly when heterogeneity of. soils and/or contamination exist. These samples can be composited for metals and semi-volatile organics, but cannot be composited for volatile organic compound (VOC) sampling. As a result, at least an equal number of discrete VOC samples must be collected for TCLP analysis. In addition, the maximum concentration of Total Petroleum Hydrocarbons (TPH) that can be disposed of at the Bovoni Dump is 100 ppm. TPH must be sampled for in all soils that may be disposed of at the dump. In the case of the sixty (60) drums of drill cuttings, adequate sampling to assess disposal options would have been the following: 1) Six (6) composite samples for TCLP analysis for metals and semivolatiles 2) Six (6) discrete samples for TCLP analysis of VOCs. 3) Six (6) composite samples for TPH (biased toward visibly stained soils). 4) Six (6) discrete samples for Target Compound List (TCL) VOCs (biased toward more grossly contaminated material based on field screening) TUT 006 O463 This sampling scheme will be required for all future waste characterization of soils at the Tutu Well field Site. If you have any questions regarding this matter please contact me at (809) 774-3320. Sincerely yours, Leonard Reed Assistant Director cc: ^Caroline Kwan, EPA Charles Zombro, PWD Jack McBurney, de maximis TUT 006 O464