Hudson River Public Water System 2009 Phase 1 Monitoring Program Summary

From May through November 2009, the New York State Department of Health (NYSDOH) collected water samples for polychlorinated biphenyl (PCB) analysis from public water systems on the Hudson River. The monitoring program was developed to provide information about the systems during the dredging of PCB-contaminated Hudson River sediments by the General Electric Company. These samples were compared to samples collected prior to dredging, to help us understand if water quality changed. 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).

The baseline monitoring included systems in the Upper and Lower Hudson Rivers. We intended to include the same systems for the Phase 1 monitoring. However, prior to the start of dredging, Stillwater received a carbon filtration system from the US Environmental Protection Agency (USEPA) to remove PCBs from their well water, while Waterford and Halfmoon decided to use finished drinking water from Troy. As there were no Upper Hudson River systems actively using the river as a water source during dredging, we focused on four Lower Hudson River systems: Green Island, Rhinebeck, Port Ewen and Poughkeepsie. These systems were sampled approximately every two weeks.

Two methods were used to analyze the samples for PCBs. One was an Aroclor Method, similar to the 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.

Using the Green Bay Method, PCBs in raw water ranged from less than 9.1 ng/L to 57.5 ng/L, and PCBs in finished water ranged from less than 9.1 ng/L to 29.7 ng/L. Using the Aroclor Method, PCBs in finished water ranged from less than 6.1 ng/L to 71.5 ng/L (see Table 1). These data are within the range of the PCB concentrations measured during the 2008 baseline monitoring and as indicated above, all results are below the drinking water standard of 500 ng/L.

Our 2008 and 2009 monitoring programs were funded by the USEPA. The USEPA expects dredging to resume in May 2011.

The NYSDOH will continue to work with water systems, local health departments, the NYS Department of Environmental Conservation, local elected officials, and the USEPA to protect public water systems during dredging. If you have any questions, please call the NYSDOH at 518-402-7711.

Table 1. Results of May – November 2009 Phase 1 Monitoring at Lower 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
Lower River	Samples	Average	Minimum	Maximum	Samples	Average	Minimum	Maximum	Samples	Average	Minimum	Maximum
Green Island	9	8.3	<6.1a	33.7	9	<9.1b	<9.1	<9.1	9	<9.1	<9.1	<9.1
Rhinebeck	11	20.9	<6.1	47.2	11	16.0	<9.1	28.8	11	26.1	10.2	53.6
Port Ewen	11	22.1	<6.1	41.0	11	13.2	<9.1	19.0	11	26.1	16.9	36.1
Poughkeepsie	11	23.2	<6.1	71.5	11	12.4	<9.1	29.7	11	29.5	10.9	57.5
a<6.1 indicates the sample (or average of samples) was less than the detection limit of 6.1 ng/L for the Aroclor Method b<9.1 indicates the sample (or average of samples) was less than the detection limit of 9.1 ng/L for GBM.

Table 2. Results of May 2009 Monitoring at Stillwater to Confirm PCB Removal by GAC Filters.
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	Average	Minimum	Maximum	Samples	Average	Minimum	Maximum	Samples	Average	Minimum	Maximum
Stillwater	2	<6.1a	<6.1	<6.1	2	<9.1b	<9.1	<9.1	2	88.5	84.0	93.0
a<6.1 indicates the sample (or average of samples) was less than the detection limit of 6.1 ng/L for the Aroclor Method b<9.1 indicates the sample (or average of samples) was less than the detection limit of 9.1 ng/L for GBM.

Table 3. Results of November – December 2009 Monitoring at Halfmoon to Confirm Decline in PCB Concentrations Post-Dredging.
Data are in nanograms per liter (ng/L)

Location	Post-Filter, Pre-Chlorination Water Aroclor Method				Raw Water from River Intake Pipe Aroclor Method
Upper River	Samples	Average	Minimum	Maximum	Samples	Average	Minimum	Maximum
Halfmoon	5	8.4	<6.1a	13.9	8	28.2	17.9	34.3
a<6.1 indicates the sample (or average of samples) was less than the detection limit of 6.1 ng/L for the Aroclor Method.