Hudson River Public Water System 2008 Baseline Monitoring Program Summary
From May through November 2008, the New York State Department of Health (NYSDOH) collected water samples for PCB analysis at nine public water systems on the Hudson River. The monitoring program was developed to provide a baseline of information about the water supplies before the General Electric Company begins dredging PCB-contaminated Hudson River sediments. These baseline samples will be compared to samples collected during dredging, which will help us understand if water quality changes. Baseline samples were collected before treatment (raw water) and after treatment (finished water). All samples were found to have a PCB concentration less than the Federal and State drinking water standard of 500 nanograms per liter (ng/L).
Because they are closest to where dredging will occur, the Upper River systems at Stillwater, Halfmoon, and Waterford were sampled twice per month. The Lower River systems at Green Island, Rhinebeck, Port Ewen, and Poughkeepsie were sampled once per month. The systems at Schuylerville and Highland were sampled once (in July and November, respectively) to get additional information.
Two methods were used to analyze the samples for PCBs. One was an Aroclor Method, similar to the US Environmental Protection Agency (USEPA) Method 508 that is used by most public water systems for routine testing of PCBs. We required the laboratory to report a lower detection limit than is commonly used. (A detection limit is the smallest amount that can be measured). We used an Aroclor Method because it allows for a direct comparison to existing data from the water systems. The other method is called the Green Bay Method, which provides more detailed information about specific types of PCBs, called congeners. It has previously been used by General Electric to detect PCBs in Hudson River water.
Using the Green Bay Method, PCBs in raw water ranged from less than 9.3 ng/L to 164.0 ng/L, and PCBs in finished water ranged from less than 9.3 ng/L to 186.6 ng/L. Using the Aroclor Method, PCBs in finished water ranged from less than 5.1 ng/L to 200.9 ng/L (see Table). The USEPA expects dredging to begin in May 2009. The NYSDOH will continue to monitor the Hudson River public water systems during dredging. The NYSDOH is working with water systems, local health departments, the NYS Department of Environmental Conservation, local elected officials, and the USEPA. The baseline monitoring project was funded by USEPA. If you have any questions, please call the DOH Environmental Infoline at 1-800-458-1158 or 518-402-7711.
Results of 2008 Baseline Monitoring at Several Hudson River Public Water Systems
Data are in nanograms per liter (ng/L)
| Location | Finished Drinking Water Aroclor Method |
Finished Drinking Water Green Bay Method |
Raw Water Green Bay Method |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Upper River | Samples | Averagea | Minimum | Maximum | Samples | Average | Minimum | Maximum | Samples | Average | Minimum | Maximum |
| Schuylerville | 1 | <5.1b | -- | -- | 1 | <9.3c | -- | -- | 4 | <9.3 | <9.3 | <9.3 |
| Stillwater | 12 | 140.3 | 97.3 | 200.9 | 12 | 133.2 | 89.0 | 186.6 | 12 | 130.3 | 81.9 | 164.3 |
| Stillwater Wells | -- | -- | -- | -- | -- | -- | -- | -- | 10 | 88.8 | 42.3 | 140.0 |
| Halfmoon | 12 | 27.1 | 8.8 | 46.0 | 12 | 10.8 | <9.3 | 23.1 | 12 | 25.4 | 12.9 | 57.1 |
| Waterford | 11 | 23.7 | 9.7 | 40.5 | 11 | 12.8 | <9.3 | 72.2 | 11 | 28.2 | 11.9 | 51.6 |
| Lower River | Samples | Average | Minimum | Maximum | Samples | Average | Minimum | Maximum | Samples | Average | Minimum | Maximum |
| Green Island | 7 | 5.8 | <5.1 | 21.2 | 7 | <9.3 | <9.3 | <9.3 | 7 | <9.3 | <9.3 | <9.3 |
| Rhinebeck | 7 | 46.5 | 13.6 | 159.0 | 7 | 13.0 | <9.3 | 17.5 | 7 | 27.3 | 17.0 | 34.4 |
| Port Ewen | 7 | 16.3 | 9.9 | 21.7 | 7 | 9.4 | <9.3 | 15.2 | 7 | 24.1 | 14.7 | 40.0 |
| Poughkeepsie | 7 | 13.2 | <5.1 | 31.1 | 7 | <9.3 | <9.3 | <9.3 | 7 | 45.1 | 19.2 | 68.7 |
| Highland | 1 | 11.9 | -- | -- | 1 | <9.3 | -- | -- | 1 | 10.7 | -- | -- |
- Aroclor Method averages are based on the use of 2.5 ng/L for samples where the PCB concentration was below the MDL (five samples at Green Island and two samples at Poughkeepsie).
- <5.1 indicates the sample (or average of samples) was less than the detection limit of 5.1 ng/L for the Aroclor Method.
- <9.3 indicates the sample (or average of samples) was less than the detection limit of 9.3 ng/L for the Green Bay Method.
