CONNECTICUT CORRECTIONAL INSTITUTION
APPENDIX H - ATSDR's EXPOSURE INVESTIGATION ACTIVITIES RELATED TO PCE CONTAMINATION OF GROUNDWATER SUPPLIES IN THE OSBORN CONNECTICUT CORRECTIONAL INSTITUTION (OCCI) AREA, SOMERS, CONNECTICUT
(a/k/a SOMERS CORRECTIONAL FACILITY)
SOMERS, NEW HAVEN COUNTY, CONNECTICUT
by
MORRIS L. MASLIA, M.S.C.E., P.E.
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
Atlanta, Georgia
and
MUSTAFA M. ARAL, PH.D.,P.E.
School of Civil and Environmental Engineering
Georgia Institute of Technology
Atlanta, Georgia
Foreword
In a letter dated February 23, 1995, citizens in the Rye Hill Circle area of Somers, Connecticut, requested that the Agency for Toxic Substances and Disease Registry (ATSDR) assess their exposure to tetrachloroethylene (PCE). As a result of PCE-contaminated groundwater supplies, many of the residential wells have become contaminated with PCE that exceeds the Environmental Protection Agency's (EPA) 5 parts per billion (ppb) maximum contaminant level (MCL) for PCE.
ATSDR's Division of Health Assessment and Consultation (DHAC) conducted an exposure investigation (EI) through its Exposure Investigations Section (EIS) and the Exposure-Dose Reconstruction Project (EDRP). The EDRP, a cooperative research effort between ATSDR and the Georgia Institute of Technology (GATECH), is responsible for developing methods and computational tools to quantify levels of contaminants transported through the environment from the source of contamination to the receptor populations. Geographic Information Systems (GIS) was also incorporated in this analysis to establish spatial relationships between contaminant sources and distribution and receptor populations.
As part of the (EI), ATSDR requested the U.S. Geological Survey (USGS), through an interagency agreement, to collect and analyze regional hydrogeologic data not available to ATSDR or in the scientific literature at the time of the investigation. This report presents the findings of the EI and contains the data ATSDR asked the USGS to collect.
ATSDR'S EXPOSURE INVESTIGATION ACTIVITIES RELATED TO PCE CONTAMINATION OF GROUNDWATER SUPPLIES IN THE OSBORN CONNECTICUT CORRECTIONAL INSTITUTION (OCCI) AREA, SOMERS, CONNECTICUT
Contents
Glossary of Acronyms and Abbreviations
Exposure Investigation Activities
Public Health Implications of Exposure to PCE-Contaminated Drinking Water
LIST OF ILLUSTRATIONS
Illustrations are located in Appendix A
LIST OF TABLES
CONVERSION FACTORS
Listed below are factors to be used for converting from the inch-pound units used in the text to the International System (SI) of units and the accompanying abbreviations.
| Length | ||
| 1.0 foot (ft) | = | 0.3048 meter (m) |
| 1.0 mile (mi) | = | 1.609 kilometers (km) |
| Area | ||
| 1.0 square mile (mi2) | = | 2.590 square kilometers (km2) |
| Volume | ||
| 1.0 million gallons (Mgal) | = | 3.785 x 103 cubic meters (m3) |
| = | 3.785 x 106 liters (L) | |
| Hydraulic Conductivity | ||
| 1.0 foot per day (ft/d) | = | 3.528 x 10-4 centimeter per second (cm/s) |
= | 0.3048 meter per day (m/d) | |
| Flow | ||
| 1.0 gallon per minute (gal/min) | = | 6.309 x 10-5 cubic meter per second (m3/s) |
| 1.0 gallon per day (gal/d) | = | 0.09085 cubic meter per second (m3/s) |
| 1.0 million gallons per day (Mgal/d) | = | 0.04381 cubic meter per second (m3/s) |
| 1.0 inch per year (in/yr) | = | 25.40 millimeter per year (mm/yr) |
| Concentration | ||
| 1 part per billion (ppb) | = | 1.0 microgram per liter (µg/L) |
GLOSSARY OF ACRONYMS AND ABBREVIATIONS
Listed below are acronyms and their definitions that are used throughout this report.
| Acronym | Definition |
| ACTS | Analytical Contaminant Transport System |
| ATSDR | Agency for Toxic Substances and Disease Registry |
| CTDEP | Connecticut Department of Environmental Protection |
| DHAC | Division of Health Assessment and Consultation, ATSDR |
| DWEL | Drinking Water Equivalent Level |
| EDRP | Exposure-Dose Reconstruction Project |
| EI | Exposure Investigation |
| EPA | U. S. Environmental Protection Agency |
| GATECH | Georgia Institute of Technology |
| GIS | Geographic Information System |
| MCL | Maximum Contaminant Level |
| NPL | National Priorities List |
| PCE | Tetrachloroethylene |
| USGS | U.S. Geological Survey |
| VOC | Volatile Organic Compounds |
ATSDR'S EXPOSURE INVESTIGATION ACTIVITIES RELATED TO PCE CONTAMINATION OF GROUNDWATER SUPPLIES IN THE OSBORN CONNECTICUT CORRECTIONAL INSTITUTION (OCCI) AREA, SOMERS, CONNECTICUT
by Morris L. Maslia(1) and Mustafa M. Aral(2)
ABSTRACT
Tetrachloroethylene (PCE) has been detected in groundwater supplies in the Osborn Connecticut Correctional Institution (OCCI) area, including the Rye Hill Circle neighborhood, in Somers, Conn.(3) Contaminant concentrations based on measured groundwater samples were found to range from nearly 5,000 parts per billion on the OCCI property to more than 500 parts per billion in 1 residential well.(4) In the residential wells, PCE concentrations ranged from 545 parts per billion to below detection limits. Estimates based on analysis of groundwater movement by use of field data and computational methods indicate that residential wells in the Rye Hill Circle area have probably been contaminated since their installation in 1978 through 1981. Thus, citizens have probably been exposed to PCE-contaminated water for 16 years from 1978 through 1993, when carbon-activated filters were installed on each well.
Background
Citizens of the Rye Hill Circle area of Somers, Conn., sent a letter to the assistant administrator, Agency for Toxic Substances and Disease Registry (ATSDR), February 23, 1995, asking that ATSDR assess the citizens' exposure to tetrachloroethylene (PCE). As a result of PCE-contaminated groundwater resources, many of the residential wells in the Rye Hill Circle area and two of the Osborn Connecticut Correctional Institution (OCCI) production wells have become contaminated with PCE at levels that exceed the Environmental Protection Agency's (EPA) 5 ppb maximum contaminant level (MCL). In response to the citizens' request, ATSDR initiated an exposure investigation (EI) as part of the public health assessment process.
ATSDR's Division of Health Assessment and Consultation (DHAC) conducted its investigation through the Exposure Investigations Section (EIS) and the Exposure-Dose Reconstruction Project (EDRP). Through an interagency agreement, ATSDR asked the Connecticut District, Water Resources Division, of the U.S. Geological Survey (USGS), to collect and analyze regional hydrogeologic data not available to ATSDR or in the scientific literature at the time of the investigation. This EI report also presents the data the USGS gathered (Appendix B).
The ATSDR EI addresses two issues in response to the citizens' request: (1) estimating the length of time the residents in the Rye Hill Circle were obtaining PCE-contaminated water from their wells and (2) reconstructing historical levels of PCE contamination to estimate exposure to PCE-contaminated groundwater. ATSDR responded to the requests with the following activities:
(1) analyzed site and off-site hydrogeologic and geochemistry data by
(2) analyzed the movement of PCE through the glacial material in the OCCI sand filter bed area by using analytical contaminant transport modeling techniques;
(3) characterized and analyzed groundwater flow in the bedrock aquifer in the OCCI and the Rye Hill Circle areas by using numerical groundwater flow modeling techniques; and
(4) reconstructed historical PCE concentration levels for the bedrock aquifer in the OCCI and the Rye Hill Circle areas and estimated the duration of residential exposure to PCE-contaminated groundwater by using numerical contaminant transport modeling techniques.
Previous Investigations
Previous investigations in the study area have included evaluations of the following:
locating additional groundwater supplies in the surficial and bedrock aquifers (Fuss & O'Neill, 1992a);
soil gas in two potential PCE source areas at the OCCI facility (Fuss & O'Neill, 1992b);
PCE contamination of the overlying glacial aquifer and in the bedrock aquifer on the OCCI property (Fuss & O'Neill, 1993);
the environment in the vicinity of the former sand filter beds at the OCCI facility (Fuss & O'Neill, 1994a);
the hydrogeology and assessment of PCE contamination of the bedrock aquifer in the OCCI area (Fuss & O'Neill, 1994b).
The investigations in 1993 and 1994 inventoried residential wells and determined PCE contamination in water samples from the wells. ATSDR has completed a health consultation for the town of Somers (ATSDR, 1994) and most recently a petitioned public health assessment for the area (ATSDR, 1995).
EXPOSURE INVESTIGATION ACTIVITIES
Site and Off-Site Data
The OCCI and the Rye Hill Circle area are in Tolland County, town of Somers, north-central Connecticut, near the Connecticut-Massachusetts border, in the Connecticut Valley lowlands topographic region (Figs. 1 and 2). The site of the EI has been the subject of ongoing hydrogeologic investigations (Fuss & O'Neill, 1992a; 1992b; 1993; 1994a; 1994b). In addition to these investigations, the USGS collected and analyzed hydrogeologic data in the area from the Connecticut River to the Eastern Border Fault. Appendix B of this report contains the data. A review of these data indicates that groundwater in the area of the site generally occurs in two aquifers: (1) the fine-grained drift aquifers of the Upper Connecticut River Valley and (2) an extensive bedrock aquifer, the Portland Arkose. The fine-grained stratified drift aquifers are capable of providing only limited supplies of groundwater and generally produce yields of 10 gal/min or less. The domestic wells in the Rye Hill Circle area and the OCCI production wells are all cased through the overlying surficial material and obtain water from the underlying bedrock aquifer. Thus, the surficial aquifer is not a direct source of potable water for site wells. In terms of the EI, the overlying surficial aquifer is considered important only in terms of providing recharge to the underlying bedrock aquifer and the degree to which the surficial materials retard or enhance the movement of contaminants from land surface to the bedrock aquifer.
Vertical Migration of PCE Through the Overlying Glacial Till
Figure 3 is a hydrogeologic cross section (B-B') in the vicinity of the sand filter bed area (see Fig. 2 for location of cross section B-B'). The sand filter bed area has been acknowledged as one of the most likely sources for the PCE contamination. Groundwater samples from the bedrock aquifer directly below this area have resulted in the highest concentrations of PCE-contaminated groundwater for the bedrock aquifer (Fuss & O'Neill, 1993; 1994b). The glacial till in this area is approximately 55 ft thick (including the thickness of the sand filter bed). To estimate the time for vertical migration of contaminated groundwater, we used ATSDR's analytical contaminant transport system (ACTS) software package (Aral, 1996) to apply a one-dimensional contaminant transport equation to a vertical distance represented by section B-B' (Fig. 3). We conducted several simulations using both deterministic (single value parameter estimates) and uncertainty (Monte Carlo) analysis to account for variations in site parameter values. We obtained parameter values used in the simulations from site data (Fuss & O'Neill, 1993; 1994a) and from published literature values (Anderson, 1979; Freeze and Cherry, 1979; Gelhar, et. al., 1992).
Table 1 lists the simulations for the glacial till conducted as part of the EI and the ranges in parameter values used for each simulation. Figures 4 and 5, respectively, present results of the simulations for Run01 (single value analysis) and Run07_mc (Monte Carlo analysis). Results in Figure 4 indicate that after 1 year (360 days), the concentration of PCE at the top of the bedrock aquifer would be about 70% of the initial PCE concentration in the sand filter bed. Thus, based on an initial concentration of about 1,800 ppb (Fuss & O'Neill, 1994a), groundwater with a PCE concentration of greater than 1,200 ppb would reach the top of the bedrock aquifer within one year. Results of the Monte Carlo analysis (Fig. 5) indicate that there is a greater than 95% probability that groundwater contaminated with PCE exceeding the MCL of 5 ppb reaches the top of the bedrock aquifer within one year. The implication of these result is that, for an estimated total exposure period of more than 15 years, the time for movement of PCE-contaminated groundwater through the overlying glacial till is insignificant and can be ignored in quantifying exposure from the PCE-contaminated groundwater of the bedrock aquifer.
Table 1. List of simulations and parameter value ranges used for simulating one-dimensional vertical transport of PCE through glacial till.
| Simulation Number | Simulation Type | Groundwater Velocity (ft/d) | Dispersion Coefficient (ft2/d) | ||||
| Mean | Range | Distribution Type | Mean | Range | Distribution Type | ||
| Run01 | Single Value | 0.11 | N/A* | N/A | 2.45 | N/A | N/A |
| Run02 | Single Value | 0.11 | N/A | N/A | 0.70 | N/A | N/A |
| Run03 | Single Value | 0.88 | N/A | N/A | 19.6 | N/A | N/A |
| Run04 | Single Value | 0.88 | N/A | N/A | 5.6 | N/A | N/A |
| Run01_mc | Monte Carlo 1,000 terms |
0.3 | 0.11 - 0.88 | Lognormal | 3.7 | 0.7 - 19.6 | Lognormal |
| Run02_mc | Monte Carlo 5,000 terms |
0.3 | 0.11 - 0.88 | Lognormal | 3.7 | 0.7 - 19.6 | Lognormal |
| Run03_mc | Monte Carlo 1,000 terms |
0.3 | 0.11 - 0.88 | Lognormal | 3.7 | 0.7 - 19.6 | Exponential |
| Run04_mc | Monte Carlo 1,000 terms |
0.3 | 0.11 - 0.88 | Exponential | 3.7 | 0.7 - 19.6 | Exponential |
| Run07_mc | Monte Carlo 1,000 terms |
0.1 | 0.001 - 1.0 | Lognormal | 5.0 | 0.1 - 100 | Lognormal |
*N/A, not applicable to this simulation type.
Characterization of Groundwater Flow in the Bedrock Aquifer
The USGS has characterized groundwater flow in the bedrock aquifer in an area of north-central Connecticut from the Eastern Border Fault to the Connecticut River (Appendix B). The regional groundwater flow is generally from the eastern highlands across the lowlands to the Connecticut valley toward the Connecticut River. In the EI area, wells used for potable water in the OCCI and the Rye Hill Circle area withdraw water solely from the bedrock aquifer. There are four production wells on the OCCI property (PW-1, PW-2, PW-3, and PW-4 on Fig. 2). While all four wells are available for use, well PW-2 has excessive PCE contamination and operates only in emergency situations. Table 2 lists wells depths and water production data from October 1993 for the OCCI wells.
Table 2. OCCI production well data, October 1993*
| Construction and Production Data | Production Wells | |||
| PW-1 | PW-2** | PW-3 | PW-4 | |
| Ground Elevation (ft) | 305 | 260 | 275 | 250 |
| Well Depth (ft) | 900 | 500 | 500 | 500 |
| Depth to Bedrock (ft) | 80 | 52 | 59 | 41 |
| Design Pumping Rate (gal/min) | -- | 150 | 200 | 150 |
| Actual Pumping Rate (gal/min) | 43 | 0 | 80 | 135 |
| Actual Daily Yield (gal/d) | 49,000 | 0 | 48,000 | 81,000 |
In the Rye Hill Circle area, there are approximately 92 domestic wells that withdraw water from the bedrock aquifer (Fig. 2). We do not know actual water use for individual domestic wells before 1994. During 1994, the Connecticut Department of Environmental Protection (CTDEP) gathered monthly water use data by metering 38 of the wells (R. Fill, written commun., 1995). The data indicate that the average daily household water use for July 1994 was 287 gal/d. As a comparison, the U.S. daily per capita water use (which includes domestic, commercial, industrial, and public use) ranges from 60 to 250 gal/d (Fair, et. al., 1971). Thus, for an average 4-person household, the U.S. daily per capita rate would result in water usage of about 240 to 1,000 gal/d for the Rye Hill Circle area.
To characterize and better understand the nature of groundwater flow in the area of the EI, we calibrated a numerical groundwater flow model using hydrogeologic and water-use data described above. We used the steady-state layered aquifer model (SLAM) code (Aral, 1989) to simulate groundwater flow in the study area. Comparisons of model calibrated water-level values with those measured for August 1994 are in good agreement and are shown in figure 6. The local direction of groundwater flow, based on model simulation appear in figure 7. A review of modeling results (Figs. 6 and 7) indicates that groundwater flow in the northern and southern parts of the EI area, is consistent with the regional gradient and is from east to west. However, near the sand filter bed area, groundwater flow is complex, divergent, and nonuniform. In this area, groundwater--and presumably contaminants dissolved in groundwater such as PCE--can move north, south, and to the west of the source of contamination. Thus, contamination originating in the sand filter bed area could be transported and dispersed to the north of this area (OCCI production well area) and to the south (Rye Hill Circle area wells) by the action of pumping wells and the movement of groundwater through fracture and bedding-plane zones characteristic of the bedrock aquifer.
Reconstruction of Historical PCE Concentrations in the Bedrock Aquifer
We used the CLAM code (Tang and Aral, 1992), a numerical contaminant transport model, to reconstruct historical levels of PCE in the bedrock aquifer and to quantify exposure to PCE-contaminated groundwater. Among the input used by the CLAM code was the simulated velocity field (Fig. 7) and aquifer parameter values determined during the groundwater flow model calibration process. We made the following assumptions in conducting the transport simulations:
(1) Contamination of the bedrock aquifer began when OCCI operations began and for modeling purposes this was assumed to be January 1, 1963. All four OCCI production wells were operational at this time.
(2) Domestic well usage in the Rye Hill Circle area began on January 1, 1978. All domestic wells and OCCI production wells were operational at this time.
(3) Because of excessive PCE concentration, OCCI production well PW-2 (Fig. 2) ceased operating in June 1990. Therefore, for modeling purposes, for the period of July 1, 1990, through December 31, 1993, OCCI production wells PW-1, PW-3, and PW-4 and all domestic wells in the Rye Hill Circle area were operational.
(4) All exposure to PCE-contaminated groundwater ceased after December 31, 1993, because of the installation of carbon-activated filters on the domestic wells in the Rye Hill Circle area.
Each time a well was put into or taken out of service, we used the SLAM code to generate a new velocity (flow) field. We then used the simulated velocity field as one of the inputs for the contaminant transport simulation. For the study area, we generated three different velocity fields based on the pumping conditions described above in items 1-3.
Because of uncertainty as to when contamination began, the precise location of the source of contamination, and the concentration of the source of contamination, we conducted many simulation scenarios to determine the effect of parameter variation on the estimated levels of PCE contamination. Based on review of the many simulations, the most likely scenario for contamination of groundwater supplies in the EI area and thereby exposure to PCE is the following:
(1) OCCI operations contaminated the sand filter bed area with PCE.
(2) The PCE volatilized and went back into solution, contaminating groundwater in the glacial till.
(3) Contaminated groundwater in the glacial till spread laterally as well as moving vertically, infiltrating the bedrock aquifer.
(4) In addition to PCE-contaminated infiltration from the overlying glacial till, PCE moved vertically downward into the top of the bedrock aquifer because of density effects (Pankow and Cherry, 1996) and contaminated the bedrock directly below the sand filter bed area.
(5) Simulation results indicate that when the domestic wells in the northern part of the Rye Hill Circle area began to use groundwater in 1978, the bedrock aquifer was already contaminated with PCE that exceeded the MCL of 5 ppb.
Simulation results for Rye Hill Circle well RHC-082, and OCCI monitoring well MW-5D are shown in Figure 8 (see Fig. 2 for well locations). This illustration shows time versus concentration of PCE for these wells as simulated by the model and the PCE concentration in the well obtained during water-quality sampling for the third quarter of 1993. These results indicate that based on available data and modeling scenarios tested, the highest concentrations of PCE occurred in 1993. In addition, the results show that when the domestic well was installed (1978), the bedrock aquifer was already contaminated. Specific results for other wells will vary depending on several factors including proximity to the OCCI production wells, proximity to the sand filter bed area, depth of well, and pumping rate. However, all wells generally will have the same characteristics as shown by wells RHC-082 and MW-5D (Fig. 8).
PUBLIC HEALTH IMPLICATIONS OF EXPOSURE TO PCE-CONTAMINATED DRINKING WATER
The highest measured level of PCE in the Rye Hill Circle area wells was 545 ppb for well RHC-082 (Fig. 8). This is 9% higher than the PCE Drinking Water Equivalent Level (DWEL) of 500 ppb (IRIS, 1994), which is a lifetime exposure level specific for drinking water at which adverse noncarcinogenic health effects would not be expected to occur. However, the DWEL for PCE includes an uncertainty factor of 1,000 and corresponds to an equivalent dose in humans of 1,000 times lower than no effect level observed in animal studies (IRIS, 1994). Thus, it is unlikely that past consumption of the most highly contaminated well water in the Rye Hill Circle area would have resulted in any acute toxic effects in the affected residents of this area. Furthermore, based on available toxicological data and studies (ATSDR, 1994), no long-term adverse human health effects, including cancer, are likely to occur in the future as a result of past exposure to and consumption of PCE-contaminated water by residents in the Rye Hill Circle area. However, because PCE has been shown to cause cancer in animals, continued use of filters or connecting to public water supplies is a prudent public health practice and will further reduce risks to area residents.
CONCLUSIONS
Based on review of available data and use of computational models, the exposure investigation activities resulted in the following conclusions:
(b) the highest measured and simulated concentrations of PCE-contaminated groundwater in the OCCI and Rye Hill Circle area wells occurred during the third quarter of 1993 (for example, well MW-5D had a measured value of 770 ppb and a simulated value of 846 ppb; well RHC-082 had a measured value of 545 ppb and a simulated value of 521 ppb).
(b) infiltration of PCE-contaminated groundwater from the overlying glacial material to the bedrock aquifer,
(c) additional undocumented sources of PCE, or
(d) some combination of all of the above factors.
REFERENCES
Anderson, M.P., 1979, Using Models to Simulate the Movement of Contaminants Through Groundwater Flow Systems, Critical Reviews in Environmental Control, v. 9, no. 2, pp. 97-156.
Agency for Toxic Substances and Disease Registry (ATSDR), 1994, Health Consultation for Town of Somers (Somers Correctional Facility), Somers, Connecticut, November 1994.
Agency for Toxic Substances and Disease Registry (ATSDR), 1995, Petitioned Public Health Assessment, Osborn Connecticut Correctional Institution (a/k/a Somers Correctional Facility), Somers, Tolland County, Connecticut, Cerclis No. CTD980522940, [working draft].
Aral, M.M., 1989, Ground Water Modeling in Multilayer Aquifers, Steady Flow (SLAM), Lewis Publishers, Chelsea, Michigan, 114 p.
Aral, M.M., 1996, Analytical Contaminant Transport System (ACTS) Software (version 2.5), submitted to the Agency for Toxic Substances and Disease Registry by the School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, February 1996 [unpublished document].
Fair, G.D., Geyer, J.C., and Okun, D.A., 1971, Elements of Water Supply and Waste Disposal, John Wiley & Sons, Inc., New York, 752 p.
Fill, R., 1995, Facsimile Transmission from State of Connecticut Department of Environmental Protection, Population and Water Usage Information, Somers, Connecticut, December, 1995.
Freeze, R.A., Cherry, J.A., 1979, Groundwater, Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 604 p.
Fuss & O'Neill, 1992a, Hydrogeologic Investigation, Enfield/Somers Correctional Facilities, Enfield/Somers Connecticut, January 1992.
Fuss & O'Neill, 1992b, Results of PCE Source Investigation -- Phase I, Somers Maximum Security Correctional Facility, Somers, Connecticut, November 1992.
Fuss & O'Neill, 1993, PCE Source Investigation--Phase II, Somers Correctional Facility, Somers Connecticut, October 1993.
Fuss & O'Neill, 1994a, Environmental Investigation, Former Sand Filter Bed Area, Osborn CCI, Somers, Connecticut, November, 1994.
Fuss & O'Neill, 1994b, Bedrock Aquifer Assessment, Osborn CCI, Somers, Connecticut, December 1994.
Gelhar, L.W., Welty, C., and Rehfeldt, K.R., 1992, A Critical Review of Data on Field-Scale Dispersion in Aquifers, Water Resources Research, v. 28, no.7, pp. 1955-1974.
IRIS, 1994, Integrated Risk Information System, U.S. Environmental Protection Agency, Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, Ohio.
Pankow, J.F., and Cherry, J.A., 1996, Dense Chlorinated Solvents and other DNAPLS in Groundwater, Waterloo Press, Portland, Oregon, 522 p.
Tang, Y., and Aral, M.M., 1992, Contaminant Transport in Layered Aquifer Media (CLAM), Georgia Institute of Technology Report No. CE512, 235 p.
APPENDIX A - Illustrations
Figures 1 - 8
APPENDIX B -
Characterization of Groundwater Flow Between the Eastern Border Fault and the Connecticut River in North-Central Connecticut,Hartford and Tolland Counties, Connecticut
1. Technical Project Officer and Research Hydrologist, Division of Health Assessment and Consultation, ATSDR, 1600 Clifton Road, Mail Stop E-32, Atlanta, Georgia 30333.
2. Principal Investigator and Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332.
3. Refer to the Contents section of the report for a list of acronyms, abbreviations, and their definitions.
4. Refer to the Contents section of the report for a list of conversion factors from inch-pound units to International System (SI) of units and the appropriate abbreviations.
