° p.^ '_. • o' ' X-" ' '>\j p. ­ J'-^^ V , r\ j ' . / ': t^'. ^­~ rr'- i=^''' ,<=!> OO P ^,? ^^ ^:^­ o & ' ' • \ / - ^ Commission Report #149 HYDROGEOLOGICAL INVESTIGATION OF THE MOTTOLO HAZARDOUS WASTE SITE RAYMOND, NEW HAMPSHIRE Hydrogeological Investigation Unit New Hampshire Water Supply and Pollution Control Commission August 1986 I EXECUTIVE SUMMARY The Mottolo Hazardous Waste Site is located in a rural section of the Town of Raymond, New Hampshire. Over 1,600 pails and drums of various hazardous wastes were disposed of in a quarter of an acre open face dump from approximately 1975 thru 1979. The pails, drums and some contami­ nated soil were excavated and secured in an emergency removal action by the United States Environmental Protection Agency in 1980 and 1981 and were removed from the site in 1981 and 1982. The NHWS&PCC Hydrogeological Investigation Unit began a hydrogeologi­ cal investigation of the Mottolo Site in March 1985 to update the pre­ vious site information and to better define the area of contamination and the potential receptors at risk. The Unit's hydrogeological investiga­ tion included a fracture fabric analysis of the bedrock geology of the area, selected geophysical surveys, a hydrochemical reconnaissance of the site, the installation of ten additional monitoring wells, the measure­ ment of groundwater and surface water elevations and the sampling of monitoring wells, residential wells and nearby surface waters. The investigation indicated that there are no additional areas of buried metal containers at the site, but that residual contamination emanating from the former drum disposal area is continuing to adversely impact the groundwater and surface waters near the site. A main plume of groundwater contaminated with measurable levels of volatile organic chemicals is emanating from the former drum disposal area and has mi­ grated towards an unnamed tributary of the Exeter River, referred to as Brook A in this report. Volatile organic chemicals have been detected in the overburden and bedrock aquifers and along a reach of Brook A. No impact has been detected to date in nearby residential bedrock and over­ burden wells or in Brook A at the Randy Lane Culvert approximately 1,800 feet downstream of the site. However, volatile organic chemicals were also detected at a bedrock/overburden monitoring well couplet approxi­ mately 230 feet downstream of the main plume of contaminated groundwater, which may be the result of transmission in the bedrock aquifer and sub­ sequent discharge to the overburden aquifer. Groundwater elevation data indicate that the upland area near the former drum disposal area is a local recharge area and groundwater flow is northeasterly towards Brook A where the overburden and bedrock aquifers discharge to the surface water drainage system of Brook A. Although no impact has been detected to date in any of the residential water supply wells, it should be noted that the water supply wells in the area will be at risk until soil and groundwater contamination at the site is mitigated. Future studies and remedial cleanup actions at the site should be performed in accordance with the National Contingency Plan. n TABLE OF CONTENTS Page 1.0 INTRODUCTION 1 1.1 Site Background Information 1 1.2 Nature and Extent of Problem 5 1.3 Hydrogeological Investigation 6 1.4 Overview of Report 9 2.0 SITE FEATURES INVESTIGATION 11 2.1 Demography 11 2.2 Land Use 11 2.3 Natural Resources 13 2.4 Climatology 13 3.0 HAZARDOUS SUBSTANCES INVESTIGATION 16 3.1 Waste Types 16 4.0 HYDROGEOLOGICAL INVESTIGATION. 18 4.1 Geology 18 4.1.1 Previous Investigations 18 4.1.2 Surficial and Bedrock Geology 20 4.1.2.1 Fracture Fabric Analysis 21 4.1.2.2 Introduction 21 4.1.2.3 Conclusions from the Fracture Fabric Analysis 22 4.1.3 Geophysical Surveys 24 4.1.4 Proton Precession Magnetometer Profiles 25 4.1.4.1 Introduction and Survey Design 25 4.1.4.2 Presentation of Data and Analysis 25 4.1.5 Seismic Refraction Survey 27 4.1.5.1 Introduction and Survey Design 27 4.1.5.2 Presentation of Data and Analysis 30 4.1.6 Electrical Resistivity Surveys 33 4.1.6.1 Introduction and Survey Design 33 4.1.6.2 Presentation of Data and Analysis 36 4.2 Groundwater 38 4.2.1 Previous Investigations 38 4.2.2 Electromagnetic Survey 40 4.2.2.1 Introduction and Survey Design 40 4.2.2.2 Presentation of Data and Analysis 41 4.2.3 Hydrochemical Reconnaissance 41 4.2..3.1 Introduction and Survey Design 41 4.2.3.2 Soil Gas Sampling 43 4.2.3.3 Micropiezometers 47 4.2.3.4 Surface Water Samples 51 4.2.3.5 Presentation of Data and Analysis 51 4.2.4 Monitoring Well Program 54 4.2.4.1 Siting, Design and Installation 54 4.2.4.2 Hydraulic Testing 58 4.2.4.3 Overburden and Bedrock Aquifers 59 iii TABLE OF CONTENTS (continued) Page 4.2.5 Water Quality Analysis 63 4.2.6 Water Level Measurements 75 5.0 SURFACE WATER INVESTIGATION 81 5.1 Surface Water 81 6.0 AIR INVESTIGATION 89 7.0 ENVIRONMENTAL CONCERNS 90 7,1 Potential Receptors 90 REFERENCES 92 IV LIST OF FIGURES Page FIGURE 1 Location Map 2 FIGURE 2 Site Map 4 FIGURE 3 Area Map , 12 FIGURE 4 Photolineaments Composite Map 23 FIGURE 5 Location Map, Magnetic Lines 26 FIGURE 6 Magnetic Survey Results - March 8, 1985 28 FIGURE 7 Magnetic Survey Results - April 16, 1985 29 FIGURE 8 Geophysical Surveys Location Map 31 FIGURE 9 Interpreted Seismic Refraction Profiles 32 FIGURE 10 Compariison of Electrical Resistivity Configuration 35 FIGURE 11 Resistivity Double Dipole Pseudo Section 39 FIGURE 12 Electromagnetic Contour Map 42 FIGURE 13 Hydrochemical Reconnaissance - Sampling Locations 44 FIGURE 14 Schematic of Soil Gas Sampling Method 46 FIGURE 16 Typical Micropiezometer Installation 48 FIGURE 16 Hydrochemical Reconnaissance Results 52 FIGURE 17 Geologic Cross Section 60 FIGURE 18 Bedrock Surface Contour Map 62 FIGURE 19 Areal Extent of Volatile Organic Contamination ­ August 21-22, 1985 71 FIGURE 20 Location Map - Residential Wells 74 FIGURE 21 Overburden Groundwater Elevations - August 22, 1985 77 FIGURE 22 Bedrock Groundwater Elevations - August 22, 1985 78 FIGURE 23 Surface Water Samples - Site Locations 84 FIGURE 24 Off-Site Surface Water Sampling Locations 85 V LIST OF TABLES Page TABLE 1 Interpreted Seismic Velocities 30 TABLE 2 Resistivity Value Interpretations 37 TABLE 3 Summary of Micropiezometer Construction and Comparative Water Level Measurements 50 TABLE 4 Slug Test Results 58 TABLE 5 Groundwater Quality Summary - Volatile Organic Chemicals 67 TABLE 6 Range of Concentrations - Volatile Organic Chemicals 70 TABLE 7 Inorganic Analyses Summary - Groundwater and Surface Water 73 TABLE 8 Groundwater Velocities and Times of Travel 79 TABLE 9 Summary of Surface Water Quality Data - Volatile 87. Organic Chemicals VI LIST OF APPENDICES Page Appendix A Geophysical Data A-1 thru A-50 Appendix B Fracture Fabric Analysis Histograms and Aerial Photographs B-l thru B-3 Appendix C Well and Test Pit Data C-1 thru C-49 Appendix D Water Quality Data... D-l thru D-125 Appendix E Slug Test and Water Elevation Data E-1 thru E-17 vn 1.0 INTRODUCTION 1.1 SITE BACKGROUND INFORMATION The Mottolo Site is located on Blueberry Hill Road in the Town of Raymond, New Hampshire, approximately 3.2 miles south of the center of Raymond (Figure 1). The site is located in a rural area characterized by undeveloped wooded land and single family residences. The site was discovered in April 1979 in response to a complaint from a local official. Initial site reconnaissance revealed a small open face dump, approximately one quarter of an acre in area, being operated for the disposal of drums and pails containing various hazardous wastes. At that time the site consisted of an access road, three buildings used as part of a former piggery operation which was not active at the time of site discovery, a pile of manure and miscellaneous wastes produced from the former piggery operation, two abandoned trucks and the drum disposal area. A leachate seep was observed emanating from the toe of the drum disposal area and flowing northeasterly towards an unnamed brook (1). Surface water was also observed contacting the toe of the dump. The former piggery operation/drum disposal area was located in approximately two acres of open land in the southwest portion of a fifty acre parcel of property owned by Richard Mottolo. In 1979 the primary concerns were the water supply wells of several single family homes located on Blueberry Hill Road to the north and northwest of the site and the potential con­ tamination of the Exeter River which was used to supply drinking water to the Town of Exeter. More than 1,600 drums and pails were disposed of in the dump area just north of the main piggery building. The wastes were believed to - 1 ­ FIGURE 1 LOCATION MAP-MOTTOLO SITE RAYMOND, N.H. - 2 ­ have been disposed of during a 4-5 year period prior to 1979, when'the disposal operation ceased. The apparent method of disposal was to dump the drums and pails and apply a top layer of soil cover to allow access for subsequent waste disposal at the open face of the dump. In 1980 the United States Environmental Protection Agency (USEPA), Environmental Services Division initiated site activity to excavate and remove the buried wastes. Prior to the excavation of waste the following site preparation actions were taken: 1) surface water was diverted away from the toe of the dump by constructing a diversion swale and a soil berm, 2) an area north of the disposal area was cleared and graded for the tempo­ rary staging of excavated materials and 3) a temporary access road was constructed to that staging area.