OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM 94.13 Evaluation of the Churn Splitter for Inclusion in the Division Protocol for the Collection and Processing of Surface-Water Samples for Subsequent Determination of Trace Elements, Nutrients, and Major Ions in Filtered Water April 21, 1994 OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM 94.13 Subject: Evaluation of the Churn Splitter for Inclusion in the Division Protocol for the Collection and Processing of Surface-Water Samples for Subsequent Determination of Trace Elements, Nutrients, and Major Ions in Filtered Water INTRODUCTION The new inorganic protocol for filtered water (Office of Water Quality Technical Memorandum 94.09) requires the use of a modified churn splitter for purposes of compositing cross-sectional whole water samples. The new protocol was developed for the constituents and reporting limits listed in Table 1. For the majority of the trace elements, the reporting limit is 1 microgram per liter (ug/L). However, the reporting limit for iron (Fe), aluminum (Al), and zinc (Zn) is 3 ug/L. This limit was raised well beyond current quantification capabilities because these trace elements are commonly present in most field and laboratory working environments and, therefore, are very difficult to eliminate as contaminants. Sample contamination typically falls into two categories--consistent or erratic. The cleaning, handling, and processing procedures included in the new protocol are designed to limit consistent contamination to less than half the stated reporting limits. The same procedures are also selected because they substantially reduce the chances of erratic contamination. The quality assurance/quality control (QA/QC) procedures and guidelines incorporated in the protocol are intended to provide adequate checks on potential sample contamination. Further, the QC data generated under the protocol are intended to provide defensible environmental data of known quality. Such information is a requisite for data interpretation. PURPOSE Since the new protocol was published, questions have arisen concerning the data supporting the use of the churn splitter. The purposes of this memorandum are to provide the justifying data and to certify the churn splitter for use with the protocol. SCOPE As is stated in the protocol, use of the churn requires (1) putting a limited diameter funnel in the lid, (2) enclosing the churn inside two sealable polyethylene or polypropylene bags and placing these inside a churn carrier, and (3) replacing the existing spigot valve with a new one from the Quality of Water Service Unit (Ocala). An appropriate number of field blanks (defined in the protocol) should be run when any samples are collected. Furthermore, because the protocol was developed for filtered samples, an additional field blank should be run (including passing water through the spigot) when unfiltered samples are collected. RINSING AND CONDITIONING SOLUTION TESTS During the initial development of the protocol, a series of laboratory tests evaluated the effectiveness of preconditioning the processing equipment with deionized water (DIW) rather than with native water. Samples from five streams were processed and analyzed, and the results compared. Before filtering samples, a blank was run through the entire processing system (churn splitter, pump tubing, 142-millimeter (mm) plate filter, and a 142-mm 0.45-um MFS filter) to evaluate whether the filtrates might be contaminated from the processing equipment. The equipment was thoroughly cleaned between each processed sample using the procedure provided in the protocol. After all the samples had been run, the system was cleaned one final time, and a final blank was run in the same manner as the first. The results for all the blank samples are in Table 2. The data listed in the rows marked "Conditioning Blank" represent duplicate aliquots of DIW used to condition the processing system. The data listed in the rows marked "Equipment Blank" come from the two separate aliquots of DIW that were actually passed through the processing system. Equipment Blank 1 was run at the beginning of the tests, whereas Equipment Blank 2 was run after all environmental samples had been processed. Little or no contamination was detected in blanks from the processing equipment. CARRYOVER AND FIELD CLEANING TESTS During the development of the office- and field-cleaning procedures, questions arose about potential "contaminant" carryover if a sample was obtained at a highly contaminated site followed by collection of a sample at a relatively pristine site. An evaluation of this potential problem, which would also provide a test for the proposed field-cleaning procedures, was designed and implemented. The two test sites were (1) Davis Mill Creek, in Copper Hill, Tennessee, and (2) Broad River at Bell, near Elberton, Georgia. Flow at the Davis Mill Creek site is highly contaminated by acidic discharges from abandoned copper mines, as well as by effluent from a chemical company. The Broad River site is in a rural, agricultural area. Both sites had been used extensively for previous studies on the evaluation of dewatering equipment. The Davis Mill Creek site was sampled first. All the appropriate sampling and processing equipment had been cleaned and packaged in appropriate noncontaminating plastic containers in the office the previous day. Upon arrival at the site, a series of environmental subsamples was collected using a weighted bottle and composited in a standard 14-L churn splitter. The composite sample was processed using a peristaltic pump, silicon pump tubing, a GeoTech 142-mm nonmetallic filtering system, and a 142-mm 0.45-um MFS filter. The filtrate was split between two bottles and acidified with Ultrex nitric acid. After the processing was completed, all equipment was thoroughly field cleaned. A new filter was placed in the filter holder, preconditioned with DIW, and a field blank was processed. The equipment was then repackaged in plastic bags for the drive to the Broad River site. Upon arrival at the second site, the procedure used at Davis Mill Creek was repeated. A sample was collected, composited, and processed. The system subsequently was disassembled and field cleaned, and a final field blank was processed. The data for the actual samples and the subsequent blanks are presented in Table 3. The Davis Mill Creek site contained substantial quantities of "dissolved" iron (Fe), manganese (Mn), cobalt (Co), copper (Cu), and zinc (Zn). The analytical data for the subsequent blank indicate that the field cleaning was sufficient to remove any traces of the processed sample as indicated by the low and/or "less than" concentrations of Fe, Mn, Co, Cu, and Zn. The source(s) for the measurable silver (Ag) in the blank is unknown. The Broad River sample contained little or no detectable trace elements or major ions, and the subsequent blank was essentially as clean as the one processed at the Davis Mill Creek site. Again, as with the Davis Mill Creek blank, Ag was detected, the source(s) of which is also unknown. LOUISIANA SIDE-BY-SIDE FILTRATION ARTIFACT TESTS During the development of the inorganic protocol, results from a series of filtration tests indicated that the type of filter used to process whole-water samples could have a substantial effect on "dissolved" trace-element concentrations (Horowitz and others, 1992). A further evaluation of this phenomenon was planned and carried out at three sites (Mississippi River at St. Francisville, Tangipahoa River at Robert, and Big Creek at Pollack) in Louisiana. The tests entailed the following: (1) all the equipment was cleaned following the procedures detailed in the protocol; (2) upon arrival at the site, a field blank using inorganic blank water (IBW) obtained from the Quality of Water Service Unit (Ocala) was processed and preserved following the procedures outlined in the protocol; and (3) a field sample was collected, processed, and preserved following the procedures outlined in the protocol. The data for the field blanks using capsule filters are provided in Table 4; the data indicate that the office-cleaned equipment and the field-collection and processing procedures used with the IBW are capable of limiting contamination to acceptable levels. ENVIRONMENT CANADA/USGS/CANADIAN GEOLOGICAL SURVEY SIDE-BY-SIDE FILTRATION ARTIFACT TESTS Based on mutual interest in further evaluating the effects of filtration artifacts on "dissolved" trace-element concentrations, a series of tests were planned by representatives of the USGS/WRD, Environment Canada, and the Canadian Geological Survey. The actual experimental work was carried out by Environment Canada at their St. Lawrence Center in Montreal. Five different samples were collected for processing: (1) a sample from an acid mine drainage site, (2) a sample from a peat bog, (3) a sample containing a high suspended sediment concentration from the St. Lawrence River, (4) a sample containing a low suspended-sediment concentration from the St. Lawrence River, and (5) a sample from a near-neutral or alkaline river site. The samples were collected and brought to Montreal for processing. All the processing equipment (churn splitter, pump tubing, and various filters and filter holders) was cleaned per the protocol. Actual processing was carried out inside a laminar flow hood in a laboratory. Before processing each sample, a blank was run through each system. After each environmental sample was processed, the system was recleaned following the field-cleaning procedures described in the protocol. Before running the next sample, a new equipment blank was processed. This continued until all the samples had been processed through a variety of filtration devices. The acid mine drainage sample was processed first, followed by the peat bog sample, followed by the others. The filtrates resulting from all the processed samples and blanks were split and subsequently analyzed by both the USGS National Water Quality Laboratory (NWQL) and the Canadian Geological Survey (Ottawa). The chemical data from both facilities are comparable. Table 5 contains USGS/NWQL-generated chemical data for both the blanks, as well as the acid mine and peat bog samples (2 of the 5 samples run during the experiment) processed with capsule filters. These two samples were selected because they were run in sequence and represent the worst-case scenario of a sample containing relatively low trace-element concentrations following the processing of one containing relatively high concentrations. The data indicate that (1) the processing equipment started out at acceptably clean levels, (2) the acid mine drainage sample contained substantial amounts of selected trace elements (Mn, Ni, Cu, Zn, and Cd), (3) there were elevated Al and Zn levels in the acid mine drainage blanks, (4) the cleaning procedure readily removed residues from the acid mine sample before processing the next blank, (5) the peat bog sample did not contain excessive amounts of trace elements, and (6) the residues from the peat bog sample also were readily removed before processing the next blank (Table 5). The source(s) for the elevated Zn concentration in the first equipment blank is unknown; however, based on the results from the other blanks run during this study it should be viewed as erratic rather than consistent contamination (that is, it did not result from problems associated with the actual cleaning procedures because it did not show up in the other blanks). The Al concentration (1.4 ug/L) in the second equipment blank is elevated, but is viewed as being at an acceptable level because it is less than half the Al reporting limit (3 ug/L). The source(s) of the elevated B levels in the blanks and samples is unknown at the present time. CONCLUSIONS Data cited in this memorandum indicate that the cleaning procedures (office and field) incorporated in the new protocol limit consistent contamination associated with the churn splitter to concentrations less than one half the reporting limit. The extent to which some trace elements in blank samples were detected is typical of erratic contamination detected during normal quality-control tests. The data support the view that the cleaning procedures outlined in the protocol are appropriate for rendering the churn splitter sufficiently clean for use at the reporting limits listed in Table 1. REFERENCE CITED Horowitz, A.J., Elrick, K.A., and Colberg, M.R., 1992, The effect of membrane filtration artifacts on dissolved trace element concentrations: Water Resources, v. 26, p. 753-763. David A. Rickert Chief, Office of Water Quality Attachment (see hard copy) This memorandum refers to Office of Water Quality Technical Memorandum 94.09. Key Words: Analysis, protocol, surface water Distribution: A, B, S, FO, PO, AH Churn Splitter Data [all concentrations in ug/L except Ca, Mg, Na, and Si (mg/L)] ------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------ Table 1: Reporting Limits for the Constituents Covered by the Dissolved Inorganic Protocol MS MS AES MS MS MS MS MS MS MS MS MS MS MS MS MS AES AES AES AES AES AES AES Be Al Fe Cr Mn Co Ni Cu Zn Mo Ag Cd Sb Ba Pb U B Li V Sr Ca Mg Na Si -------------------------------------------------------------------------------------------------------------------- 0.5 3.0 3 1 1 1 1 1 3.0 1 1 1 1 1 1 1 1 4 6 0.5 0.02 0.01 0.2 0.01 Table 2: System Tests During Evaluations of Rinsing and Conditioning Solutions (Lab Environment) AES AES AES AES AES GF GF AES AES GF GF AES GF AES AES AES AES AES AES AES Sample Be Ye Cr Mn Co Ni Cu Zn Mo Ag Cd Ba Pb Li V Sr Ca Mg Na Si ------------------------------------------------------------------------------------------------------------------------------ Conditioning Blank <0.5 <3 <5 <1 <3 <1 0.8 <3 <10 <1 <0.1 <1 <1 <4 <6 <0.5 <0.2 <0.1 <0.2 0.01 Conditioning Blank <0.5 <3 <5 <1 <3 <1 1.2 <3 <10 <1 <0.1 <1 <1 <4 <6 <0.5 <0.2 <0.1 <0.2 0.02 Equipment Blank 1 <0.5 <3 <5 <1 <3 <1 <0.1 <3 <10 <1 <0.1 <1 <1 <4 <6 <0.5 <0.2 <0.1 <0.2 0.02 Equipment Blank 2 <0.5 <3 <5 <1 <3 <1 0.1 <3 <10 <1 <0.1 <1 <1 <4 <6 <0.5 <0.2 <0.1 <0.2 0.02 Table 3: System Tests During Evaluations of Carryover and Field Cleaning Procedures (Field Trials) AES AES AES AES AES GF GF AES AES GF GF AES GF AES AES AES AES AES AES AES Sample Be Fe Cr Mn Co Ni Cu Zn Mo Ag Cd Ba Pb Li V Sr Ca Mg Na Si -------------------------------------------------------------------------------------------------------------------------------------- Initial Field Blank <0.5 <3 <5 <1 <3 2 <1 <3 <10 <1 <0.1 <1 <1 <4 <6 0.9 0.16 <0.01 <0.2 0.01 Davis Mill Creek Sample <0.5 51,000 <5 5400 126 20 315 5500 <10 1 4.1 20 1 8 <6 150 96 13 11.7 9.4 Field Blank After Cleanup <0.5 4 <5 <1 <3 <1 <1 <3 <10 8 <0.1 <1 <1 <4 <6 <0.5 0.02 <0.01 <0.2 0.01 Broad River at Bell <0.5 365 <5 16 <3 <1 <1 <3 <10 4 <0.1 11 <1 <4 <6 35 4.3 1.7 4.4 15 Field Blank After Cleanup <0.5 <3 <5 <1 <3 <1 <1 <3 <10 7 <0.1 <1 <1 <4 <6 <0.5 <0.02 <0.01 <0.2 <0.01 Table 4: Field Blanks from Various Sites in Louisiana MS MS AES MS MS MS MS MS MS MS MS MS MS MS MS MS AES AES AES AES AES AES AES AES Sample Be Al Fe Cr Mn Co Ni Cu Zn Mo Ag Cd Sb Ba Pb U B Li V Sr Ca Mg Na Si --------------------------------------------------------------------------------------------------------------------------------------------------------- Miss. R. @ St. Francisville <0.2 <0.2 <3 <0.2 <0.2 <0.2 <0.2 0.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <2 <4 <6 <0.5 <0.02 <0.01 <0.2 0.01 Tangipahoa @ Robert <0.2 <0.2 <3 <0.2 <0.2 <0.2 <0.2 0.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 2 <4 <6 <0.5 <0.02 <0.01 <0.2 0.06 Big Creek @ Pollack <0.2 <0.2 <3 <0.2 <0.2 <0.2 0.8 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <2 <4 <6 <0.5 <0.02 <0.01 <0.2 0.02 Tangipahoa @ Robert <0.2 0.3 <3 0.2 0.2 <0.2 <0.5 0.4 1.0 <0.5 <0.3 <0.3 <0.3 <0.4 <0.3 <0.2 <2 <4 <6 <0.5 0.1 <0.01 <0.2 0.04 Table 5: Test Data From the Canadian-USGS Side-by-Side Filtration Artifact Study MS MS AES MS MS MS MS MS MS MS MS MS MS MS MS MS AES AES AES AES AES AES AES AES Sample Be Al Fe Cr Mn Co Ni Cu Zn Mo Ag Cd Sb Ba Pb U B Li V Sr Ca Mg Na Si ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- System Blank <0.2 0.3 <3 <0.2 1.0 <0.2 <0.5 3.4 3.4 <0.2 <0.2 <0.3 <0.2 <0.4 <0.3 <0.2 11.9 <4 <6 0.6 <0.02 <0.01 <0.2 0.01 Acid Mine Drainage Sample <0.2 7.4 3.0 <0.2 1700 10 65 16 2500 <0.2 <0.2 17 <0.2 21 <0.3 0.23 16.3 5.9 <6 500 130 62 3.6 6.5 System Blank <0.2 1.4 <3 <0.2 0.1 <0.2 <0.5 0.3 0.6 <0.2 <0.2 <0.3 <0.2 <0.4 <0.3 <0.2 19.0 <4 <6 <0.5 <0.02 <0.01 <0.2 0.02 Peat Bog Sample <0.2 149 118 <0.2 1.0 <0.2 0.7 1.7 4.8 3.1 <0.2 0.1 <0.2 9.1 1.5 <0.2 9.7 <4 <6 29 4.3 0.4 1.8 6.4 System Blank <0.2 <0.3 <3 0.5 0.3 0.3 <0.5 <0.3 <0.5 <0.2 <0.2 <0.3 <0.2 <0.4 <0.3 <0.2 <2 <4 <6 <0.5 <0.02 <0.01 <0.2 0.0