Here we report optical data collected as part of a collaborative study between USGS Pennsylvania Water Science Center, Pennsylvania Department of Environmental Protection and Water Mission Area Proxies Project. The optical measurements reported here were collected to aide in the characterization of water sources and mixtures and establish proxies (surrogates) for per- and poly-fluorinated alkyl substances within the Neshaminy Creek basin. Data are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary file of commonly extracted optical indicators and field-based sensor arrays.

Optical sensors measuring fluorescence of non-biological sources (e.g., dissolved organic matter, wastewater, hydrocarbons, fluorescent dyes, etc.; hereafter referred to as fDOM) are increasingly used in water quality studies because they provide proxy measurements for a variety of contaminants and constituents of concern including metals, wastewater effluent, and DOM (measured in the lab as dissolved organic carbon, (DOC)) concentrations. Similarly, sensors measuring biological (algal) fluorescence (hereafter referred to as chlorophyll (fChl) and phycocyanin (fPC), have gained popularity to measure phytoplankton concentration, biomass, and even primary productivity. As additional sensors are coupled with ongoing field monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e., pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field, allowing for the standardization of United States Geological Survey (USGS) measurements across the entire agency. Here, we present the results of testing a multiparameter field standard (MPFS), an experimental mixed standard solution capable of simultaneously verifying calibrations for multiple fluorescence sensors (fDOM, fChl, and fPC).

Optical spectra reported here are collected from 17 surface water sampling sites within the Fraser River, a headwaters drainage of the Upper Colorado River Basin in the central western United States. The sample collection was conducted as part of the partnership between the United States Geological Survey’s (USGS) Next Generation Water Observation System (NGWOS) and Proxies Project, in coordination with the USGS Colorado Water Science Center and California Water Science Center, and the East Grand Water Quality Board.

Fluorescence and absorbance spectra were measured in discrete surface water samples collected during three sampling campaigns (Nov 2022, Mar/Apr 2023, Jul 2023) on the Illinois Waterway (IWW) and Chicago Area Waterway System (CAWS), which are the primary drainage of the Illinois River Basin (IRB). Water sampling was conducted concurrently with a boat-based water quality mapping effort using the Fast Limnology Automated Measurement (FLAMe) system (Crawford et al., 2015). Each campaign began in the Chicago metropolitan area, and after having sampled Lake Michigan, entered into the upper extent of the IWW, sampling through the CAWS into the lower reaches of the Des Plaines River and finally the Illinois River. After 8-10 days of traveling downriver through the IWW, sampling ended in the Mississippi River upstream of St Louis, Missouri. Discrete water quality samples were collected from various sites that include main channel, tributaries, and off-channel areas (e.g., backwaters) from a depth of 1 meter (m), typically in the center of the channel or aquatic feature. Between 25 and 40 sites were sampled per campaign dependent upon river conditions and boat accessibility. Data reported here are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary optical measurements commonly used in statistical analyses.

Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various approaches. As additional sensors are grouped for in situ monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e. pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field to standardize USGS measurements among sensors and across the landscape. Here, we present the results of a mixed standard solution capable of simultaneously verifying calibrations for multiple sensors including fluorescence of dissolved organic matter (fDOM) and fluorescence of chlorophyll-a (fChl).

One phenomenon that has been shown to concentrate and release per- and polyfluoroalkyl substances (PFAS) in surface water is the formation of natural foams. For surface water foams to form, surface active compounds or surfactants must be present in the water along with a source of gas bubbles. Some examples of surface-active compounds include humic and fulvic acids, colloidal particles, and lipids and proteins. The relationship between PFAS and dissolved organic matter (DOM) is important because studies have shown that DOM can affect PFAS fate and bioavailability in aquatic systems and treatment processes. The results from this assessment will improve our understanding of PFAS fate and transport in the environment. Surface water and foam samples were collected from two sub-basins in the Delaware River Basin to compare PFAS, PFAS total oxidizable precursors (TOP), and DOM concentrations and composition in surface water foams to that of underlying bulk water, upstream water, and downstream water. Data were collected in support of the U.S. Geological Survey (USGS) Water Mission Area Integrated Water Availability Assessments program in coordination with the Pennsylvania Department of Environmental Protection (PADEP) and USGS Water Science Centers in Pennsylvania and California.

One phenomenon that has been shown to concentrate and release per- and polyfluoroalkyl substances (PFAS) in surface water is the formation of natural foams. For surface water foams to form, surface active compounds or surfactants must be present in the water along with a source of gas bubbles. Some examples of surface-active compounds include humic and fulvic acids, colloidal particles, and lipids and proteins. The relationship between PFAS and dissolved organic matter (DOM) is important because studies have shown that DOM can affect PFAS fate and bioavailability in aquatic systems and treatment processes. The results from this assessment will improve our understanding of PFAS fate and transport in the environment. Surface water and foam samples were collected from two sub-basins in the Delaware River Basin to compare PFAS, PFAS total oxidizable precursors (TOP), and DOM concentrations and composition in surface water foams to that of underlying bulk water, upstream water, and downstream water. Data were collected in support of the U.S. Geological Survey (USGS) Water Mission Area Integrated Water Availability Assessments program in coordination with the Pennsylvania Department of Environmental Protection (PADEP) and USGS Water Science Centers in Pennsylvania and California.

The use of field-deployable fluorescence sensors to better understand dissolved organic matter concentrations and composition has grown immensely in recent years. Applications of these sensors to critical monitoring efforts have also grown to encompass post-fire monitoring, wastewater tracking, and use as a proxy for various contaminants. Despite the growth, it is well known that these sensors are subject to various interferences and require corrections for temperature, turbidity, and concentration effects. Although temperature corrections are widely applicable across sensors, the turbidity and concentration corrections can be site-specific and/or sensor-specific. The corrections can even be subject to changes in manufacturing within a sensor type, as has been raised as a concern for the USGS’s most widely used fDOM (fluorescence of dissolved organic matter) sensor manufactured by Xylem/YSI. Currently there is limited guidance on the proper corrections for sensors used within the USGS. As the use of these sensors continues to grow, the need for greater standardization of the measurements among sites and through time will also grow. This data release compiles the measurements collected from multiple lab experiments using Elliot Silt Loam. The data contained herein will be used to assess the variability of fDOM corrections for turbidity.

Here, we present the results supporting Table 2 in Field Techniques for Fluorescence Measurements Targeting Dissolved Organic Matter, Hydrocarbons, and Wastewater in Environmental Waters: Principles and Guidelines for Instrument Selection, Operation and Maintenance, Quality Assurance, and Data Reporting. Table 2 shows comparisons from an Aqualog 800 benchtop fluorometer standardized to quinine sulfate equivalents (QSE) with excitation (ex) and emissions (em) equivalent to fluorescence of dissolved organic matter (fDOM) sensors from multiple manufacturers. Data are reported from two standard reference materials (SRM) and the mean, minimum, and maximum from 76 environmental samples. No replicates were collected for environmental samples; therefore, the relative standard deviation is not available.

Here, we present the results supporting Table 2 in Field Techniques for Fluorescence Measurements Targeting Dissolved Organic Matter, Hydrocarbons, and Wastewater in Environmental Waters: Principles and Guidelines for Instrument Selection, Operation and Maintenance, Quality Assurance, and Data Reporting. Table 2 shows comparisons from an Aqualog 800 benchtop fluorometer standardized to quinine sulfate equivalents (QSE) with excitation (ex) and emissions (em) equivalent to fluorescence of dissolved organic matter (fDOM) sensors from multiple manufacturers. Data are reported from two standard reference materials (SRM) and the mean, minimum, and maximum from 76 environmental samples. No replicates were collected for environmental samples; therefore, the relative standard deviation is not available.