December 22, 2004

John P. Miller

President

National Chromium, Inc.

10 Senexet Road

Putnam, CT 06260

RE:2004 Annual Report on the Operation of the Groundwater Extraction Well at National Chromium, Inc., Putnam, CT

Dear Mr. Miller,

Metcalf & Eddy is pleased to provide National Chromium, Inc. with two copies of the 2004 Annual Report on the Operation of the Groundwater Extraction Well at the National Chromium facility in Putnam, Connecticut. This report satisfies annual Connecticut Department of Environmental Protection (CTDEP) reporting requirements specified in the facility “Groundwater Monitoring Plan and Evaluation of Effectiveness of Recovery Well” document (National Chromium, 2000). These requirements were amended in the letter from Metcalf & Eddy to National Chromium, Inc., dated February 8, 2002, to address CTDEP’s comments, presented in a letter dated January 15, 2002, regarding the 2001 annual report.

The discussion and conclusions presented in the report are based on the groundwater sampling and water level measurement events conducted at National Chromium since operation of the well was commenced in 1995.

If you have any questions or we can provide any additional information, please feel free to contact us. Thank you for this opportunity.

Very truly yours,

Metcalf & Eddy, Inc.

William A. Baker, IV, P.E.Lucas A. Hellerich, Ph.D., P.E.

AssociateProjectEngineer

cc: File

w/ attachment

National Chromium, Inc.

Putnam, Connecticut

2004 Annual Report on the Operation of the Groundwater Extraction Well at National Chromium, Inc., Putnam, CT

Prepared for:

National Chromium, Inc.

10 Senexet Road

Putnam, CT06260

Prepared By:

Metcalf & Eddy, Inc.

860 North Main Street Extension

Wallingford, CT 06492

Report Date:

December 2004


Table of Contents

1.Introduction and Objectives

2.Previous Work

3.Monitoring Activities Performed

4.Extraction Well Operation and Maintenance

5.Hydrogeologic Data

6.Geochemical Data

7.Effectiveness of Groundwater Recovery Well

8.References

Appendix A Statement of Limitations

Appendix B Tables and Figures

Appendix C Correspondence

Appendix D Daily Pumping Rates

Appendix E Well Sampling Data Sheets

Appendix F Analytical Data

1

X:\036200134 (National Chromium)\GW Ext Well Report 2004\GW extraction well annual report 2004 Final.doc

1.Introduction and Objectives

This report represents the annual reporting requirements contained in the “Ground Water Monitoring Plan and Evaluation of Effectiveness of Recovery Well” document presented to Maurice Hamel of the Connecticut Department of Environmental Protection (CTDEP) by National Chromium, Inc. in November 2000. These requirements were amended in the letter from Metcalf & Eddy to National Chromium, Inc., dated February 8, 2002, to address CTDEP’s comments, presented in a letter dated January 15, 2002,regarding the 2001 annual report. The January 15, 2002 and February 8, 2002 letters are provided in Appendix C. This report is subject to the Statement of Limitations presented in Appendix A. The annual report is required to contain:

  1. Quarterly water table levels for monitoring wells 1, 5, 6, 7, 8, 9, 10, 11S, 11D, 12, C, D, PA12, PA25, PA40, PB12, PB25, and PB40.
  2. A water table map depicting the minimum containment zone observed over the year of groundwater level measurements.
  3. Monthly chromium concentrations for the recovery well and semi-annual chromium concentrations for monitoring wells 7, 8, 9, 11S, 11D, and 12.
  4. Monthly pH readings for the recovery well and semi-annual pH readings for monitoring wells 7, 8, 9, 11S, 11D, and 12.
  5. Discussion of down-gradient groundwater quality using the data from monitoring well 12.
  6. Annual concentrations for total chromium, hexavalent chromium, cadmium, copper, nickel, and zinc, and pH for the recovery well and monitoring wells 8, 9, 11S, and 11D.
  7. Semi-annual concentrations of hexavalent chromium in PA40 and PB40 to assess the approximate width of the contaminant plume with respect to the location of the interceptor well.
  8. Discussion of extraction rates.
  9. A discussion of the zone of capture and of the extraction well’s ability to continue capturing the contaminated plume, containing the migration of the contaminant plume, and of the water quality trends, including a comparison of observed chromium mass removal rates to predicted rates (Nikolaidis / Shen model).

A map of the National Chromium, Inc. site is presented as Figure 1 in Appendix B and the locations of the wells examined in this report are presented on the figure.

A semi-annual report was submitted in June 2004 and a copy of the cover letter for that report is included in Appendix C.

2.Previous Work

Relevant work performed at the site previously by others is summarized below. Dr. Nikolaos Nikolaidis and Lucas Hellerich performed an assessment of the groundwater recovery well (Figure 1 in Appendix B) at the National Chromium facility in Putnam, CT in the fall of 1999. The results of this assessment were presented in the Nikolaidis and Hellerich (2000) report titled “Assessment of the Extraction Well Effectiveness in Capturing Chromium Contamination in the Groundwater at National Chromium, Inc.”. The report was then revised with a response letter dated April 18, 2000to address comments presented by Maurice Hamel about the report.

During the assessment, the following activities were performed:

  1. The transverse extents of the chromium plume were delineated in the vicinity of the extraction well using direct push technology and aqueous sampling.
  2. Pumping tests using the extraction well were performed to determine the radius of influence of the extraction well at flowrates of 10 and 26 GPM.
  3. A confirmation analysis of the cone of influence (zone of capture) and a comparison with previous work performed by Lucas Hellerich and Huiying Shen was conducted.
  4. A brief assessment was performed comparing recovery rates for chromium observed to date and rates anticipated by the conceptual model of mobility prepared by UCONN.
  5. A determination of the minimum pumping rate and maximum shutdown time to achieve containment of the chromium contaminant plume was performed using the results of the pumping tests and the MODFLOW groundwater model.

The significant findings of the assessment were:

  1. The total width of the chromium plume is approximately 130 feet. The plume extends approximately 55 feet east of ML1B and 75 feet west of ML1B (Figure 1 in Appendix B).
  2. The cone of influence from the extraction well was calculated to be 77 feet in the east direction and 60.8 ft in the west direction from the well. The results of the pumping tests indicated that the cone of influence actually extends beyond PROF-7 and PROF-5 (Figure 1 in Appendix B) and that the extraction well effectively captures the chromium plume under seasonal low and high water tables.
  3. The pumping tests confirmed the calculated capture zone. In his doctoral dissertation, Huiying Shen, estimated the capture zone under a pumping regime of 20 GPM. He calculated that the cone of influence was 25 m or 83 feet diameter.
  4. Dr. Shen's model predicted that during the first two years within commencement of pumping activities, 1,222 Kg of chromium would be extracted and during the second two years, 428 Kg. The first two years the prediction was within 8% of the observed values and the second two years the prediction was within 32%. Given the uncertainty in the actual estimation of the recovery mass using quarterly measurements, the results of the modeling predictions are considered consistent with the field data.
  5. If the well is operated continuously for 18 out of 24 hours, a rate of 10 GPM is the minimum rate to effectively capture the contamination under conditions of low and high water table. When the well is operated at a low rate of 10 gpm for 18 hours out of a 24 hour day, the maximum allowable shut-down time for the well is 14 days.

Lucas Hellerich completed the 2000 Annual Report on the Operation of the Groundwater Extraction Well at National Chromium facility in Putnam, Connecticut in December 2000 (Hellerich, 2000).

Metcalf & Eddy completed the 2001, 2002, and 2003Annual Reports on the Operation of the Groundwater Extraction Well at National Chromium facility in Putnam, Connecticut in December of each of these years (M&E, 2001; M&E, 2002; M&E, 2003).

3.Monitoring Activities Performed

The monitoring activities performed during 2004 are listed below. Groundwater and operational monitoring measurements were performed by National Chromium, Inc. and/or Premier Laboratory (Dayville, CT) personnel. Analytical measurements were performed by Premier Laboratory.

Daily Monitoring Activity

Groundwater recovery well water volume pumped each day, by shift, was recorded. Daily pumping rates are provided in Appendix D.

Monthly Monitoring Activity

Groundwater from the groundwater recovery well was sampled and analyzed for total chromium and pH monthly.

Quarterly Monitoring Activity

The groundwater levels from monitoring wells 1, 5, 6, 7, 8, 9, 10, 11S, 11D, 12, C, D, PA12, PA25, PA40, PB12, PB25, and PB40 were measured quarterly (March, June, September, and December, 2004).

Semi-Annual Monitoring Activity

Groundwater from wells 7, 8, 9, 11S, 11D, and 12 was sampled and analyzed for total chromium and pH semi-annually (March and September, 2004).

The groundwater from PA40 and PB40 was sampled and analyzed for hexavalent chromium semi-annually(March and September, 2004).

Annual Monitoring Activity

The groundwater from the recovery well and monitoring wells 8, 9, 11S, and 11D was sampled and analyzed for total chromium, hexavalent chromium, cadmium, copper, nickel, zinc, and pH in September 2004.

Copies of well sampling sheets for the March and September monitoring events are provided in Appendix E. Copies of analytical data reports are provided in Appendix F.

4.Extraction Well Operation and Maintenance

In a letter dated January 23, 2002, the Connecticut Department of Environmental Protection approved a modification of the requirement for the pumping rate of the extraction well. A copy of this letter is included in Appendix C. The requirement for the pumping rate of the extraction well was modified to require a minimum average pumping rate of 14,400 gallons per day over a 5 day work week, with allowances granted for variability according to holiday schedules and required maintenance of the system.

A total of 4,187,800 gallons of groundwater were extracted from the aquifer in 2004 with an average extraction rate of 25.3 GPM and 16,107 gallons per day over a 5 day work week. The average extraction rate was maintained for the required number of hours and average gallons pumped per day as specified in the Operations and Maintenance Plan. Daily pumping rates are provided in Appendix D. The well was not shut down for more than 4 consecutive days (Appendix D). Monthly chromium, pH readings, and gallons extracted for the recovery well are presented below in Table 4-1. A total mass of 75 kg of chromium was recovered in 2004.

Table 4-1. Summary of Extraction Well Operation for Year 2004.

The recovery well pump wasserviced, which included verification of the pumping rate, by Pump Connection, Inc., of North Grosvenordale, CT,in July 2004 (see Appendix C for invoice).

An inspection of the swamp perimeter fence was performed by National Chromium, Inc. personnel in December 2004 (see Appendix C for memo) and there was no evidence of human entry or exit around the perimeter of the fence or within the swamp area.

5.Hydrogeologic Data

The groundwater level measurements for wells 1, 5, 6, 7, 8, 9, 10, 11S, 11D, 12, C, D, PA12, PA25, PA40, PB12, PB25, and PB40 are included in this report. The 2004 data is presented below in Table 5-1. The historic data since 1983 is presented in Table 1 in Appendix B. The groundwater elevations as a function of time for wells 1, 5, 6, 7, 8, 9, 10, 11S, 11D, 12, C, D,PA12, PA25, PA40, PB12, PB25, and PB40 are also presented graphically as Figure 2 in Appendix B. These graphs include previous data; however it should be noted that several data gaps exist in the historic data set.

Table 5-1. 2004Groundwater Elevations for Selected Wells.

Note: Groundwater elevations have units of feet above mean sea level.

Seasonal variations in the water table are evident from Figure 2 in Appendix B. The water table elevation at the site has varied from a low of 259.80 feet (Well 11D) to a high of 283.48 feet (Well 5) since initial measurements began in 1983 (Table 1 in Appendix B). During the year 2004, the difference between minimum and maximum groundwater elevations in individual wells was between a low of 1.30 feet (Well 5) and a high of 5.30 feet (Well 7), with an average difference of 3.86 feet in groundwater elevation.

The trends in water table levels as a function of time are difficult to accurately assess for all of the wells given the significant data gaps that exist (Tables 1 and 2 in Appendix B). However, since commencement of the recovery well in 1995 and discontinuance of surface water discharge to the wetland by the metal plating facility, the surface water ponding in the wetland has decreased significantly, with the exception of ponding resulting from melting snow in the spring season. This decrease in ponding is attributed to the action of the recovery well and the elimination of the surface water discharge to the wetland by the facility. Because the aquifer in the vicinity of the extraction well has a slow recharge rate in comparison to the extraction well pumping rate, drawdown of the water table in the vicinity of the extraction well occurs. This drawdown was confirmed in the assessment performed by Nikolaidis and Hellerich in 1999.

Due to their proximity to the recovery well, wells 11S, 11D, and 12 can be used to examine trends in the seasonal water table as a result of the recovery well operation. The historic water table elevation data has been compiled for wells 11S, 11D, and 12 in Table 3 of Appendix B and is also presented graphically in Figure 3A of Appendix B. The data is presented by season (Spring, Summer, Fall, and Winter) to allow for a comparison of water table variations as a function of time. As shown, the groundwater elevations for the three wells trend downward after installation of the recovery well (mid 1995). However, there are upward spikes in groundwater elevation during Summer 2000 and in 2003 and 2004. This may be due to an above average rainfall experienced at the site around the time of the groundwater level measurements.

The containment zones created by the pumping action of the recovery well were estimated based on the four quarters of water level data. Groundwater elevation contours were estimated using the groundwater level measurements. The containment zone is then defined as the area that would be captured by pumping. Figures 3B through 3E in Appendix B present these estimated containment zones.

6.Geochemical Data

Currently, the sampling interval for total chromium and pH is monthly for the recovery well and semi-annually (March and September) for wells 7, 8, 9, 11S, 11D, and 12. The total chromium and pHdata for 2004 is presented below in Tables 6-1 and 6-2.

The historic data sets for total chromium concentrations and pH readings as a function of time for the recovery welland wells 7, 8, 9, 11S, 11D, and 12 are presented in Tables 4 and 5 and graphically in Figure 4 of Appendix B. It should be noted that several data gaps exist in the historic data set.

Table 6-1. Total Chromium (mg/L) Data for 2004.

Note:

Total chromium concentration has units of mg/L.

Table 6-2. pH Data for 2004.

Notes: - pH has units of standard units.

* The 9/22/04 pH measurement at the groundwater recovery well was reported bythe analytical laboratory as 2.2; however, this value of 2.2 is significantly below anyhistorical pH measurement for this well. The value of 2.2 is expected to be a measurement error.

Total chromium concentrations and pH are experiencing opposite trends. The wells have experienced sharp declines in total chromium concentrations since commencement of the recovery well’s operation in 1995 to approximately 1997, and more gradual declines from 1997 to the present date. Total chromium concentrations in the groundwater recovery well have decreased from 250 mg/L in January 1996 to 4.4 mg/L in December 2004, with the exception of several spikes in the total chromium concentration for the groundwater recovery well. Conversely, pH values have gradually increased over time. Values of pH have increased in the groundwater recovery well from 4.3 in December 1996 to 5.7 in December 2004.

During 2004, the groundwater from the recovery well and monitoring wells 8, 9, 11S, and 11D was also sampled and analyzed for hexavalent chromium, cadmium, copper, nickel, and zinc. The2001, 2002, 2003, and 2004data are presented below along with pH and total chromium in Table 6-3.

During 2004, the groundwater from monitoring wells PA40 and PB40 was also sampled and analyzed for hexavalent chromium. The 1999 (Nikolaidis and Hellerich, 2000), 2002, 2003, and 2004 data are presented below in Table 6-4.

Table 6-3. Annual Geochemical Monitoring Activity Data.

Notes: pH has units of standard units.

Metals concentrations have units of mg/L.

The “<” indicates that parameter was not detected above concentration listed.

-- = not analyzed.

Table 6-4. PA40 and PB40 Hexavalent Chromium Data.

Notes:1.PROF-2 and PROF-4 were the Geoprobe profiling locations prior to the

installation of PA40 and PB40, respectively. PA40 and PB40 are screened across the water table from 5 to 15 feet below ground surface.

2.FT BGS = feet below ground surface.

3.The sampling depths for PA40 and PB40 were determined from the measured water levels and the bottom depth of the screened interval.

The analytical data reports are provided in Appendix F.

7.Effectiveness of Groundwater Recovery Well

Extraction rate and recovered chromium mass data for 1996 through 2004 are presented in Table 6 of Appendix B. Average annual extraction rates have varied from 15.3 to 26.2 GPM for 1997 through 2004. The average weighted extraction rate over this 8 year period was 22.7 GPM. A total mass of 2,642 kg of chromium has been removed from the aquifer since commencement of extraction operations.

The 2004 water level, chromium, and pH data indicate that the recovery well is continuing to intercept the chromium plume at National Chromium. The average pumping rate for 2004 of 16,107 GPD (based on an average 5 days of operation per work week) was greater than the minimum rate of 14,400 gallons per day over a 5 day work week approved by CTDEP and previously demonstrated to intercept the plume at seasonal low and high water tables. The water levels for wells 11S, 11D, and 12, residing within the extents of the chromium plume, have experienced significant drawdown since commencement of pumping action by the recovery well in 1995, indicating that the recovery well continues to capture chromium-contaminated groundwater at greater depths as well as at more shallow depths.