Data Series 233
U.S. GEOLOGICAL SURVEY
Data Series 233
Reservoir water samples for all analyses were collected using a 1.2-L, Teflon Kemmerer sampler (Wildco, Saginaw, MI). Procedures for collecting and processing water samples for dissolved chemical determinations are based on protocols used by the NAWQA Program (Shelton, 1994, 1997). Samples from the low-flow diversion dam (LFDD, fig. 2) were obtained as grab samples collected by submerging the sample bottle, removing the cap, filling the bottle, and recapping the bottle while still submerged. The finished (treated) drinking-water samples and imported raw-water samples were collected from spigots located at the distribution points. The water lines were flushed for 5 minutes before the sample bottles were filled.
Each primary water sample was analyzed for VOCs and pesticides at USGS National Water Quality Laboratory. The VOC analysis determined 87 compounds by purge and trap capillary-column gas chromatography/mass spectrometry (GC/MS) with full-scan ion monitoring (Connor and others, 1998). Water samples for pesticide analyses were filtered through 0.7-micrometer (nominal pore diameter) glass-fiber filters and were analyzed for pesticides using laboratory schedule 2001 at USGS NWQL. Schedule 2001 determines 47 pesticides and pesticide transformation products by C-18 solid-phase extraction (SPE) and capillary-column GC/MS with selected-ion monitoring (GC/MS-SIM) (Zaugg and others, 1995).
During the time frame of the sample collection and analyses that were performed for this report, there were no published USGS methods for the techniques used in this monitoring program to measure pesticides and PAHs, and as such, these techniques are considered “research methods.” Analytical results that were obtained using these research methods have not been entered into the USGS database, but rather are presented in this report along with a full description of the methods that were used to obtain the data.
In conjunction with the USGS, the low-volume air sampling and analytical methods for VOCs were developed by, and all samples were analyzed by, the research group of Dr. James Pankow at the Oregon Graduate Institute of the Oregon Health and Science University. The air samples for VOC analyses were collected by adsorption onto cartridges and analyzed by thermal-desorption GC/MS procedures as detailed in Pankow and others (1998). Using these procedures, ambient, gas-phase, atmospheric VOC concentrations were monitored using two programmable low-volume air sampling pumps (224-PCXR8, SKC INC., Eight Four, Pennsylvania). One type of sampler was used to pull a 1.5-L sample of air through a glass cartridge containing 50 mg of Carbotrap B in series with 280 mg of Carboxen 1000 (Supelco, Bellafonte, Pennsylvania) for the analysis of seven VOCs with the highest volatilities (lowest breakthrough volumes), including several chlorofluorocarbons. A second type of sampler was used to pull a 5-L sample of air through a glass cartridge containing 180 mg of Carbotrap B in series with 70 mg of Carboxen 1000 (Supelco, Bellafonte, Pennsylvania) for the analysis of the remaining 79 VOCs with lower volatilities (higher breakthrough volumes). Each sample was a 24-hour composite collected every 12th day. The timing of the air-sample collection for VOCs was coordinated with the CARB Air Toxics Program. Samples were analyzed for 86 VOCs, which ranged in volatility from dichlorofluoromethane (CFC-12), which had the highest volatility, to 1,2,3-trichlorobenzene, which had the lowest volatility (Pankow and others, 1998).
The research methods used in this monitoring program for sampling and analyzing semivolatile organic compounds (PAHs and pesticides) in air are comparable to those described by Foreman and others (2000) for pesticides, and to USEPA methods TO-4A for pesticides (U.S. Environmental Protection Agency, 1999a) and TO-13A for PAHs (U.S. Environmental Protection Agency, 1999b). These air methods were developed to complement the pesticides in water methods (Zaugg and others, 1995; Sandstrom and others, 2001) and PAH/alkyl-PAH in sediment method (Olson and others, 2004) applied to the SWR monitoring program.
The high-volume air samples for the analysis of PAHs or pesticides were collected by drawing air through a 90-mm diameter glass-fiber filter (GFF; type A/E, Pall Corp., East Hills, NY) followed by a cartridge containing two polyurethane foam (PUF) plugs. The GFF collects atmospheric particles from which the operationally defined particle-phase concentration of each analyte is determined. The PUF plugs collect the operationally defined gas-phase concentration of each analyte. Prior to use, the GFFs were cleaned by baking at 450 degrees Celsius (°C), desiccated for at least 2 hours until cool, weighed to the nearest 0.2 milligram (mg) on a balance, wrapped in baked aluminum foil, and stored in resealable polyethylene bags. At the SWR air-sampling site, a GFF was removed from the foil with clean (methanol-rinsed) stainless steel forceps and placed in a perfluoralkoxy fluoropolymer (Teflon-PFA) filter holder (series 90, Savillex Corp., Minnetonka, MN) that was modified in two ways. The outer closure piece of the filter holder was cut open to provide an 80-mm diameter opening that would improve air flow and expose most of the GFF surface for atmospheric particle collection. The holder’s inner closure piece was machined to include a 3.8-cm female National Pipe Thread (NPT) taper to allow direct connection to the 3.8-cm male NPT threaded connection on the inlet of the PUF cartridge.
PUF plugs for the cartridges were 5 cm in diameter by 7.6 cm long and were prepared from open-cell foam having an average density of 0.043 gm–3 and containing no polybrominated diphenyl ether flame retardants (Netherland Rubber Company, Cincinnati, OH). PUF plugs were cleaned by rinsing with tap water and then sequentially extracted for at least 12 hours each with acetone, 30-percent ethyl acetate in hexane, and dichloromethane in a Soxhlet apparatus. Residual solvent was squeezed from the PUF plugs using a stainless-steel potato masher, and the plugs were then dried in a vacuum oven at 40°C for at least 48 hours before being stored in sealed 500-mL wide-mouth jars with Teflon-lined lids. At SWR, primary (top) and secondary (bottom) PUF plugs were positioned in series inside a 24.2-cm long by 3.5-cm internal diameter Teflon-PFA cartridge (Savillex Corp., Minnetonka, MN) with the bottom PUF plug held in place against a Teflon-PFA screen. PUF plugs were carefully inserted into the PUF cartridge using clean stainless steel forceps to ensure that the PUF plugs were well fitted to the cartridge wall with no creases that would allow air to migrate around the plug instead of passing through the foam.
The PUF cartridge was then connected to the GFF filter holder, and the GFF-PUF sampling train was positioned inside a high-volume sampler enclosure (Graesby-GMW, Village of Cleves, Ohio) comparable to that described in USEPA method TO-4A (U.S. Environmental Protection Agency, 1999a). The outlet of the PUF cartridge was connected via 0.95-cm outer diameter Teflon tubing to a high-volume blower motor. Air samples were collected by pulling ambient air through the GFF-PUF sampling train at flow rates of 23 to 55 L/min for seven days, providing sample volumes ranging from 234 to 585 m3 (cubic meter) for samples described in this report. Sampling times were controlled by a timer, and sample volume was calculated by multiplying the sample collection time by the air flow rate determined using a calibrated flow meter. Following sample collection, the GFF was removed from the holder using clean forceps, returned to the aluminum foil, folded in half (particle-laden side inward), and sealed in the foil and bag. PUF plugs were returned to the jars using forceps, and the jars were labeled to identify the top or bottom PUF and were tightly sealed with the lids. GFF and PUF were stored at 4°C (maximum) prior to overnight shipment on ice to USGS NWQL.
At NWQL, air sample components were stored at –5°C (maximum) until analysis. GFFs were desiccated for 24 hours and weighed to ±0.2 mg to determine particle weight. This weight was divided by the sample’s air volume to determine the total suspended particle (TSP) concentration. Each GFF was placed in a 500-mL flat bottom flask, and each PUF plug was placed in a Soxhlet apparatus. The GFF and PUF plugs were fortified with surrogate compounds (see Quality Control section later in report) and extracted with 100-mL (GFF) or 300-mL (PUF) of 30-percent ethyl acetate in hexane for at least 12 hours. Top and bottom PUF plugs were extracted and analyzed separately during this reporting period to determine PUF collection efficiency for gas-phase analytes. Extracts were dried with sodium sulfate and reduced in volume to 1 mL using Kuderna-Danish distillation and nitrogen gas evaporation. Each extract was then transferred to a 0.5-g octadecylsilyl (C-18) solid-phase extraction (SPE) column (Isolute 221-0050-BS, Biotage AB, Charlottesville, VA) positioned over a 1-g Florisil-PR column (Isolute 712-0100-C). Analytes were eluted from these columns with 6 mL of ethyl acetate, which was reduced in volume to about 0.3 mL by nitrogen gas evaporation. Extracts were transferred with 0.15-mL ethyl acetate rinse to 2-mL GC vials containing 500 ng of 1,4-dichlorobenzene and five perdeuterated polycyclic aromatic hydrocarbons (naphthalene-d8, acenaphthene-d10, phenanthrene-d10, chrysene-d12, and perylene-d12) in ethyl acetate as internal injection standards.
The extracts were then analyzed by three different GC/MS-SIM methods. Pesticides and degradates comparable to those determined by NWQL water schedule 2001 were measured using the operational conditions described by Zaugg and others (1995) and Lindley and others (1996). A subset of parent pesticides and degradates comparable to those determined by NWQL water method 2002 were measured using the GC/MS conditions given by Sandstrom and others (2001). Finally, PAHs and alkyl-PAHs were analyzed using GC/MS conditions comparable to that described by Olson and others (2004) for a subset of those compounds determined by that sediment method except that the mass spectrometer was operated in the selected-ion monitoring mode to provide lower detection levels. Compound concentrations determined from these three methods are reported in nanograms per cubic meter of air (ng/m3).
In addition to the primary sampling of water and air to provide a core dataset for the understanding of potential water-quality impacts on the SWR, six “special studies” were conducted during the 1999−2000 time frame covered by this report. These special studies were conducted to obtain water-quality information about specific processes and chemicals of current concern. Two of these special studies (the first and the sixth) were conducted to investigate the occurrence of additional organic chemical contaminants in water using two new research methods that were under development at the NWQL. The other four special studies (the second through the fifth) used traditional methods to supplement the data from the primary sampling.
The first special study collected water samples for determination of moderate-use pesticides and degradates using procedures that subsequently became official USGS schedule 2002 (Sandstrom and others, 2001). Water samples collected by this method were filtered through 0.7-µm nominal pore size GFFs into baked 1-L sample bottles, capped, and then shipped on ice to the USGS NWQL. Analyses were performed using the C-18 SPE and GC/MS techniques described by Sandstrom and others (2001). The second special study investigated the dissolved-phase concentrations of organochlorine compounds, PAHs, and other semivolatile compounds in the SWR by use of semi-permeable membrane devices (SPMD) developed by the USGS (Huckins and others, 1990).
The third special study was an investigation of dissolved copper, which was analyzed using the same analytical methods as were used for the other water samples collected for the primary sampling, as described by Shelton (1994 and 1997). The fourth special study was an investigation of VOCs in two drinking-water production wells located north of the Reynolds desalination plant (fig. 1). The fifth special study analyzed dissolved trace metals, which were analyzed by inductively-coupled plasma/mass spectrometry using methods described in Faires (1993).
The sixth special study collected whole-water samples for the determination of wastewater indicator compounds. Samples for wastewater compounds were extracted with dichloromethane in a continuous liquid-liquid extractor. Extracts were reduced in volume to 0.5 mL by micro-Kuderna-Danish distillation and nitrogen evaporation. Perdeuterated PAH internal standards were added to the extracts and analyzed by GC/MS-SIM (samples collected in December 2000) or GC/MS operated in full scan mode (samples from March 2001). The GC/MS full scan analysis is comparable to that described by Zaugg and others (2002). All water samples for organic analyses were shipped on ice to the laboratories for analysis.
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