4. Monitoring Overview
4.1 Sample Collection and Analysis
Summaries of sampling and monitoring activities conducted in 2020 at the RDS, CDS and GWTP are included in Table 4-1. Sampling activities at the RDS followed Table 4-1of the Site Management Plan (December 2007, revised September 2014) for 2020. Monitoring wells RDS-12WS, RDS-19X, RDS-25X and P-4 were removed from the schedule, as proposed and communicated to NYSDEC in 2018. Field data collected during sampling activities is on file at Cornell and is not included in this Annual Report.
Sampling activities in 2020 at the CDS were performed in accordance with Table 4-1 of the Site Management Plan.
Sampling activities at the GWTP were completed as shown on Table 4-1 in accordance with the Substantive SPDES and Part 380 permits for the GWTP and Table 4-2 of the Site Management Plan.
Monitoring activities associated with the RDS Remedial Measures are summarized on Table 4-1. These activities were performed in accordance with Table 4-1 of the Site Management Plan.
Groundwater sampling locations for both the CDS and RDS are shown on Figure 2-1. Quarterly samples are taken in March, June, September, and December. Additional semiannual samples are taken in March and September, and additional annual samples are taken in September. Surface water sampling locations for the CDS are shown on Figure 2-1.
The water quality monitoring program for the RDS focuses on testing for paradioxane (the primary site contaminant), tritium, carbon-14 and strontium-90. The water quality monitoring program for the CDS focuses on testing for volatile organic compounds (the primary site contaminants). The monitoring program for the GWTP focuses on testing discharge from the plant to ensure compliance with the substantive SPDES permit.
In addition to water sampling, monitoring of the Remedial Measures at both sites was performed in 2020 in accordance with the approved O&M Plans or Performance Monitoring Manuals for these measures.
Source Area and PCS monitoring for the CDS was performed in accordance with the Site Management Plan. Operations at extraction well EP-2 (PCS-Shallow) and EW-3 (PCS-Deep) were discontinued as planned. Analytical data at these wells indicate only low levels of contaminants below the AWQS remain.
Cornell University personnel performed all the water sampling and routine operation and maintenance activities.
Analytical services were provided by Eurofins Testing Northeast, Inc. and GEL Laboratories.
4.2 RDS Groundwater and Surface Water Monitoring
Routine sampling of groundwater and surface water at the RDS is summarized on Table 4-1. All samples were collected as planned with the exception of surface water samples. Surface water sampling locations SW-7, SW-7E, and SW-37 were dry in June, and Septembera nd snow covered in December.
Additional surface water samples were also collected from SW-6 in June and December and additional groundwater samples were collected for low-level 1,4-dioxane analysis .
4.3 CDS Groundwater and Surface Water Monitoring
Routine sampling of groundwater and surface water at the CDS is summarized on Table 4-1. All samples were collected as planned.
Additional groundwater samples were collected for low-level 1,4-dioxane analysis.
4.4 Monitoring of Remedial Measures
Routine site monitoring for the CDS and RDS Remedial Measures (CDS PCS-Deep, RDS Groundwater Recovery System, and RDS Cap) is summarized on Table 4-1.
4.5 Groundwater Treatment Plant Monitoring
Routine Groundwater Treatment Plant monitoring is summarized on Table 4-1. All samples were collected as planned. Sampling and analysis of the RDS influent for Carbon-14,Strontium-90 and Tritium was conducted in accordance with the bag filter management plan required under the substantive Part 380 discharge permit.
An additional effluent sample was collected for low-level 1,4-dioxane analysis.