The USGS Pennsylvania Water Science Center (USGS PAWSC) in cooperation with the Pennsylvania Department of Environmental Protection (PADEP) has assembled this data release in support of ongoing USGS and PADEP evaluations related to the occurrence and distribution of Per-and Polyfluorinated Alkyl Substances (PFAS) within Pennsylvania surface water.
The data is of four general types:
1. Discrete sample (one moment in time) PFAS concentration data from untreated surface water (raw stream and raw lake water) intended to describe environmental occurrence and distribution of PFAS, not to assess risk in drinking water;
2. Quality-control (QC) PFAS data from samples intended to evaluate the effectiveness and reliability of PFAS data collection from surface water;
3. Passive sampler (time weighted average) PFAS concentration data intended to describe a monthly average of PFAS concentrations at a single site, and finally;
4. Site locations and characteristics for each sampling site within the Pennsylvania Surface Water Quality Network (WQN) information that is presented for future interpretations of this data.
Passive water samplers, unlike traditional discrete samples, can be deployed to collect data for several weeks at a time. Polar organic chemical integrative samplers (POCIS) use microporous membranes to sample hydrophilic contaminants. Eighteen POCIS were deployed for approximately one month during August and September 2019 to monitor PFAS. Six quality control samples were also collected with the environmental samples. More information about passive sampling can be found at the USGS Columbia Environmental Research Center website Passive Sampling Using SPMDs and POCIS. The USGS PAWSC has partnered with PADEP to operate the Pennsylvania Surface Water Quality Network (WQN) since 2002. Pennsylvania uses information produced from this partnership to evaluate trends in water quality, collect data to inform current or future permitting, to assess water for the Federal Clean Water Act Sections 303(d) and 305(b), and to evaluate emerging science topics, such as PFAS. This study used adapted-USGS surface-water sampling techniques to provide information on PFAS and PFAS precursor concentrations in surface water. The information presented herein is relevant to the PADEP, other state and federal agencies, local water resource managers, and the public.
The outcomes of this data collection are:
- A total of 303 samples (discrete, passive, qc) samples were collected and analyzed for this data collection effort. 180 discrete samples were collected at USGS & WQN surface water stations, with 36 QC samples, were analyzed at SGS AXYS Analytical (British Columbia, Canada) for 33 PFAS compounds and 19 PFAS precursor compounds (52 total PFAS-related analytes). 18 sites were concurrently sampled with POCIS passive samplers and 6 QC samples were collected with passive samplers that were analyzed at SGS AXYS Analytical only for the 33 PFAS compounds (not for PFAS precursor compounds). A total of 15 additional samples were analyzed by the PA DEP Bureau of Laboratories for 18 PFAS compounds to compare PFAS concentrations between two analytical methods. Finally, 48 equipment-cleaning QC blanks were collected and analyzed at the USGS National Water Quality Laboratory for 34 PFAS to evaluate cleaning effectiveness for future USGS and PA DEP studies.
- Modified USGS stream sampling protocols were determined to be reliable for sampling ng/L (parts per trillion, ppt) levels of PFAS. Insights gained will be used to inform updates the USGS National Field Manual for the Collection of Water Quality Samples.
- This first-of-its-kind PFAS dataset will improve understanding of PFAS distribution, to an extent, across the State of Pennsylvania landscape. - Inform future PFAS and ancillary data collection.
- Provide PADEP Bureau of Laboratories and the USGS National Water Quality Laboratory with surface water samples to support method validation efforts.
- This data will allow PADEP to illustrate the occurrence, distribution, and concentrations of PFAS compounds across the State of Pennsylvania. (see “Related External Resources, Type: Web Link” below).