Response to comment on "Accumulation of contaminants in fish from wastewater treatment wetlands"
No abstract available.
Environmental Science & Technology↗
Geology topics
Ronald C. Antweiler
Publications and source records attributed to Ronald C. Antweiler.
Geochemical data for mercury, methylmercury, and other constituents in sediments from Englebright Lake, California, 2002
This report presents geochemical data from two 2002 sampling campaigns conducted in Englebright Lake on the Yuba River in northern California. A deep coring campaign was done in May-June 2002 and a shallow sampling campaign was completed in October 2002. This work assessed the chemical composition of material deposited in the reservoir between 1940, the year Englebright Dam was completed, and 2002 as part of the Upper Yuba River Studies Program, an effort designed to evaluate the feasibility of introducing anadromous fish, including steelhead and spring-run Chinook salmon, upstream from Englebright Dam. Results of analyses of total mercury (HgT) in 444 subsamples, methylmercury (MeHg) in 243 subsamples, and other trace and major elements in 202 subsamples are presented. Data quality was evaluated on the basis of analyses of replicate pairs of subsamples, standard reference materials, blanks, and spike additions.Deep coring penetrated the full thickness of material deposited after 1940 at six locations in the reservoir; the cores reached a maximum depth of 32.8 meters below the reservoir floor. At the three deep coring sites closest to Englebright Dam, concentrations of HgT (dry basis) were consistently in the range of 100 to 500 ng/g (nanogram per gram), in sediment dominantly of silt size (median grain size of 0.004 to 0.063 mm [millimeter]). At the deep coring sites located farther upstream, the upper parts of the profile had lower concentrations of HgT, generally ranging from 2 to 100 ng/g, in sediment dominantly of sand size (median grain size from 0.063 to 2 mm). The lower part of the vertical profiles at three upstream coring sites had higher concentrations of HgT than the upper and middle parts of these profiles, and had finer median grain size. The highest median concentration of MeHg (1.1 ng/g) was in the top 2 cm (centimeter) of the shallow box cores. This vertical interval also had the highest value of the ratio of MeHg to HgT, 0.41 percent. Median concentrations of MeHg and median values of MeHg/HgT decreased systematically with depth from 0-4 to 4-8 to 8-12 cm in the shallow cores. However, similar systematic decreases were not observed at the meter scale in the deep cores of the MEM (MEthylMercury) series. The overall median of the ratio MeHg/HgT in the deep cores was 0.25 percent, not much less than the overall median value for the shallow cores (0.33 percent). Mercury-203 radiotracer divalent inorganic mercury (203Hg(II)) was used to determine microbial mercury-methylation potential rates for 11 samples collected from three reservoir locations and various depths in the sediment profile. For the five shallow mercury-methylation subsamples, ancillary geochemical parameters were assayed, including microbial sulfate reduction rates, sulfur speciation (sediment acid volatile sulfide, total reduced sulfur, and pore-water sulfate), iron speciation (sediment acid extractable iron(II), amorphous iron(III), crystalline iron(III) and pore-water iron(II)), pore-water chloride and dissolved organic carbon, and pH, oxidation-reduction potential (Eh) and whole-sediment organic content. The highest potential rates of microbial mercury methylation were measured in shallow (0 to 8 cm depth) sediments (5 to 30 nanograms of mercury per gram dry sediment per day), whereas potential rates for subsamples collected from depths greater than 500 cm were consistently below the detection limit of the radiotracer method (< 0.02 nanogram of mercury per gram dry sediment per day). Chemical analyses of trace and major elements in bed sediment are presented for 202 samples from deep cores from five locations in Englebright Lake. The mean values and standard deviations for selected trace elements were as follows (in micrograms per gram): antimony, 2.4 ± 1.6; arsenic, 69 ± 48; chromium, 134 ± 23; lead, 33 ± 25; and nickel, 87 ± 24. Concentrated samples of heavy-mineral grains, prepared using nine large-volume composite samples from
California↗
Accumulation of contaminants in fish from wastewater treatment wetlands
Increasing demands on water resources in arid environments make reclamation and reuse of municipal wastewater an important component of the water budget. Treatment wetlands can be an integral part of the water-reuse cycle providing both water-quality enhancement and habitat functions. When used for habitat, the bioaccumulation potential of contaminants in the wastewater is a critical consideration. Water and fish samples collected from the Tres Rios Demonstration Constructed Wetlands near Phoenix, Arizona, which uses secondary-treated wastewater to maintain an aquatic ecosystem in a desert environment, were analyzed for hydrophobic organic compounds (HOC) and trace elements. Semipermeable membrane devices (SPMD) were deployed to investigate uptake of HOC. The wetlands effectively removed HOC, and concentrations of herbicides, pesticides, and organic wastewater contaminants decreased 40−99% between inlet and outlet. Analysis of Tilapia mossambica and Gambusia affinis indicated accumulation of HOC, including p,p ‘-DDE and trans -nonachlor. The SPMD accumulated the HOC detected in the fish tissue as well as additional compounds. Trace-element concentrations in whole-fish tissue were highly variable, but were similar between the two species. Concentrations of HOC and trace elements varied in different fish tissue compartments, and concentrations in Tilapia liver tissue were greater than those in the whole organism or filet tissue. Bioconcentration factors for the trace elements ranged from 5 to 58 000 and for the HOC ranged from 530 to 150 000.
Environmental Science & Technology↗
Water-quality data from two agricultural drainage basins in northwestern Indiana and northeastern Illinois: I. Lagrangian and synoptic data, 1999-2002
Methods of data collection and results of analyses are presented for Lagrangian and synoptic water-quality data collected from two agricultural drainages, the Iroquois River in northwestern Indiana and Sugar Creek in northwestern Indiana and northeastern Illinois. During six separate sampling trips, in April, June and September 1999, May 2000, September 2001 and April 2002, 152 discrete water samples were collected to characterize the water chemistry over the course of 2 to 4 days on each of these drainages. Data were collected for nutrients, major inorganic constituents, dissolved organic carbon, trace elements, dissolved gases, total bacterial cell counts, chlorophyll- a concentrations, and suspended sediment concentrations. In addition, field measurements of streamflow, pH, specific conductance, water temperature, and dissolved oxygen concentration were made during all trips except April 1999.
Indiana, Illinois↗
Water-quality data from two agricultural drainage basins in northwestern Indiana and northeastern Illinois: II. diel data, 1999-2001
No abstract available.
Indiana, Illinois↗
Sediment chemistry of the Colorado River delta of Lake Powell, Utah, 2001
No abstract available.
Utah↗
Water-quality data from two agricultural drainage basins in northwestern Indiana and northeastern Illinois: III. biweekly data, 2000-2002
No abstract available.
Indiana, Illinois↗
Physical and chemical characteristics of Knowles, Forgotten, and Moqui Canyons, and effects of recreational use on water quality, Lake Powell, Arizona and Utah
Side canyons of Lake Powell are the most popular recreation areas of the Glen Canyon National Recreation Area in Arizona and Utah. There are more than 90 side canyons that are tributaries to the main lake body of Lake Powell. Near Bullfrog and Halls Crossing marinas in Utah, visitors frequent Knowles, Forgotten, and Moqui Canyons to fish, boat, camp, and hike the sandstone formations for which Lake Powell is famous. Areas of recreational activity are greatest near beaches in side canyons. Emissions from houseboats, personal watercraft, speedboats, and from some nonboating recreational activities introduce contaminants to the lake and to beach areas. The U.S. Geological Survey documented concentrations of trace elements, volatile organic compounds, organic wastewater contaminants, and other byproducts of fuel-based contaminants in water and bed material in Knowles, Forgotten, and Moqui Canyons during the summers of 2001 and 2002. Field work was conducted during four trips when recreational use was at a minimum (before Memorial Day in May) and when it was at a maximum (near Labor Day in September). Knowles Canyon was treated as a control; therefore, public access by motorcraft was not permitted during the study. Electric-powered or oar-powered research boats were used to collect samples and measure properties in Knowles Canyon. Record-low reservoir elevations during 2000-2002 limited the availability of camping and day-use beaches in Forgotten and Moqui Canyons. Although more beach areas were exposed during this period, the steep slopes of the beaches made it difficult to use the beaches for camping purposes. Side canyon waters of Knowles, Forgotten, and Moqui Canyons were similarly stratified (physically and chemically) during the study from natural advective and convective reservoir processes. Metalimnetic oxygen minimas were observed in September 2001 and 2002 in the side canyons and the main body of Lake Powell. Chemical concentrations of several organic constituents were elevated in Forgotten and Moqui Canyons during the high-use period in September of 2001 and 2002 compared with concentrations during the low-use period in May of 2001 and 2002. Concentrations of some constituents decreased from the mouth of each canyon to the canyon's headwaters, indicating that there could be a mechanism for constituent removal or that the main body of Lake Powell is not in equilibrium with the headwaters of the side canyons. Concentrations of volatile organic compounds, such as benzene, toluene, ethylbenzene, and xylene (BTEX compounds), were highest in the upper reaches of Forgotten and Moqui Canyons where visitor use was greatest. Trace amounts of some organic wastewater compounds, including cholesterol, N,N-diethyl-meta-toluamide (DEET), and ethylenediaminetetraacetic acid (EDTA), were measured in Forgotten and Moqui Canyons. Except for minor concentrations of some volatile organic compounds and cholesterol, contamination from visitor use in Knowles Canyon was not detected, most likely because the canyon was closed to access. Concentrations of some organic compounds in bed material sampled in the side canyons near popular beach areas, including polyaromatic hydrocarbons, were above the laboratory detection limits. Several other constituents were present in trace amounts. Benzyl n-butylphthalate and bis (2 ethyl)-phthalate were detected at concentrations above laboratory detection limits. Numerous trace elements were detected above laboratory detection limits in Knowles, Forgotten, and Moqui Canyons. All water samples from the side canyon transects had low colony counts of Escherichia coli (E. coli); the highest count was less than one-fourth of the U.S. Environmental Protection Agency recommended limit for recreational water. Four water samples collected near beaches in Moqui Canyon had E. coli colony counts that exceeded the U.S. Environmental Protection Agency recommended limit.
Arizona, Utah↗
Chemical characteristics of ground-water discharge along the south rim of Grand Canyon in Grand Canyon National Park, Arizona, 2000-2001
Springs flowing from the south rim of Grand Canyon are an important resource of Grand Canyon National Park, offering refuge to endemic and exotic terrestrial wildlife species and maintaining riparian areas. Population growth on the Coconino Plateau has increased the demand for additional development of ground-water resources, and such development could reduce spring discharge and affect the sustainability of riparian areas within the park. In addition, springs are an important source of drinking water for hikers and are culturally and economically important to Native Americans living in the region. Water samples were collected from May 2000 to September 2001 from 20 spring and creek sites that discharge water from the Redwall-Muav Limestone aquifer along the south rim of Grand Canyon. Sample collection sites were described and samples were analyzed for major ions, nutrients, trace elements, radioactivity, and selected isotopes, and potential sources of ground-water flow to the springs. Rock samples representing the major stratigraphic units of Grand Canyon were collected near the Bright Angel Fault and analyzed for mineralogy, strontium-87/strontium-86, and carbon-13/carbon-12. The chemical composition of water samples collected from a given spring did not vary appreciably over the course of the study. Although water at each spring had a temporally constant composition, the composition was chemically distinct from that of every other spring sampled, indicating spatial variability in the ground-water composition. Most samples had a calcium magnesium bicarbonate composition; a few had a substantial sulfate component. Concentrations of arsenic, nitrate, selenium, uranium, and gross alpha approached or exceeded U.S. Environmental Protection Agency Maximum Contaminant Levels in water discharging from some springs. Oxygen and hydrogen isotopic compositions varied little among samples, and for most sites the isotopic data plot close to the global meteoric water line or below the local meteoric water line. Isotopic enrichment indicates fractionation due to evaporation occurs at some sites. The evaporative process may occur prior to recharge or post-discharge. Flow paths are differentiated between the eastern part of the study area where strontium-87/strontium-86 values for water from springs and creeks are more radiogenic than strontium-87/strontium-86 values for water that discharges from sites farther west. Tritium and carbon isotope analyses indicate that residence time of ground-water discharge from springs and creeks ranges from less than 50 years to about 3,400 years. Water with a residence time of less than 50 years is absent at several sites. Discharge of most springs and creeks is a mixture of younger and older waters.
Arizona↗
Geochemical characterization of water, sediment, and biota affected by mercury contamination and acidic drainage from historical gold mining, Greenhorn Creek, Nevada County, California, 1999-2001
In 1999, the U.S. Geological Survey (USGS) initiated studies of mercury and methylmercury occurrence, transformation, and transport in the Bear River and Yuba River watersheds of the northwestern Sierra Nevada. Because these watersheds were affected by large-scale, historical gold extraction using mercury amalgamation beginning in the 1850s, they were selected for a pilot study of mercury transport by the USGS and other cooperating agencies. This report presents data on methylmercury (MeHg) and total mercury (THg) concentrations in water, bed sediment, invertebrates, and frogs collected at 40 stations during 1999-2001 in the Greenhorn Creek drainage, a major tributary to Bear River. Results document several mercury contamination “hot spots” that represent potential targets for ongoing and future remediation efforts at abandoned mine sites in the study area. Water-quality samples were collected one or more times at each of 29 stations. The concentrations of total mercury in 45 unfiltered water samples ranged from 0.80 to 153,000 nanograms per liter (ng/L); the median was 9.6 ng/L. Total mercury concentrations in filtered water (41 samples) ranged from less than 0.3 to 8,000 ng/L; the median was 2.7 ng/L. Concentrations of methylmercury in the unfiltered water (40 samples) ranged from less than 0.04 to 9.1 ng/L; the median was 0.07 ng/L. Methylmercury in filtered water (13 samples) ranged from less than 0.04 to 0.27 ng/L; the median was 0.04 ng/L. Acidic drainage with pH values as low as 3.4 was encountered in some of the mined areas. Elevated concentrations of aluminum, cadmium, copper, iron, manganese, nickel, and zinc were found at several stations, especially in the more acidic water samples. Total mercury concentrations in sediment were determined by laboratory and field methods. Total mercury concentrations (determined by laboratory methods) in ten samples from eight stations ranged from about 0.0044 to 12 µg/g (microgram per gram, equivalent to parts per million). Methylmercury concentrations in these samples ranged from less than 0.00011 to 0.0095 µg/g. A field panning method was used to determine the concentration of liquid elemental mercury in 22 samples from 14 stations. Measured quantities of elemental mercury recovered by panning ranged from a trace amount estimated at 100 milligrams per kilogram (equivalent to parts per million) to 45,000 milligrams per kilogram (equivalent to 4.5 per cent, by weight). In total, 194 invertebrate samples were collected at 31 stations; 78 of the samples were analyzed for concentrations of THg and MeHg and used to calculate MeHg to THg ratios. A total of 69 frog samples were collected at 19 stations, and all were analyzed only for THg. Ranges of MeHg concentrations (µg/g, wet weight) in invertebrate samples and number of samples (n) were 0.0012-0.048 for banana slugs (Arionidae, n = 27), 0.027-0.39 for dobsonflies (Corydalidae, n = 14), 0.029-0.50 for predaceous diving beetles (Dytiscidae, n = 31), 0.026-0.52 for predaceous stoneflies (Perlidae, n = 18), 0.011-1.6 for dragonflies (Odonata, n = 46), and 0.061-0.55 for water striders (Gerridae, n = 56). The ratio of MeHg to THg in invertebrates was greater than 50 percent for 74 of 78 samples. The data from this reconnaissance sampling effort have been used by land-management agencies in selecting abandoned mine sites for remediation. The Forest Service has remediated the Sailor Flat site, and the Bureau of Land Management has initiated plans to remediate the Boston Mine drainage tunnel.
California↗
Influence of ENSO on flood frequency along the California coast
The influence of the El Niño–Southern Oscillation (ENSO) phenomenon on flooding in California coastal streams is investigated by analyzing the annual peak floods recorded at 38 gauging stations. The state of ENSO prior to and during flooding is characterized by the multivariate ENSO index (MEI), where MEI < −0.5 is defined as the La Niña phase and MEI > 0.5 as the El Niño phase. Flood magnitude in all 20 streams located south of 35°N has a significant positive correlation ( r = 0.3 to 0.6), whereas in 3 of the 4 streams located north of 41°N flood magnitude has a significant negative correlation ( r = −0.3 to −0.4), with MEI from −2.2 to +3.2. Correlations with MEI are uniformly weak and insignificant, however, when the floods are subdivided into El Niño and non–El Niño phases. A comparison of the geometric mean El Niño flood to the geometric mean non–El Niño flood determined that the means were statistically different at gauging stations south of 35°N and north of 41°N. For 20 streams located south of 35°N, the geometric mean of annual peak floods recorded at a stream gauge during El Niño phases is 2–14 times the geometric mean of annual peak floods recorded during non–El Niño phases. Thus, south of 35°N along the California coast, floods are significantly larger during an El Niño phase than a non–El Niño phase. For the three streams located north of 41°N, the geometric mean of annual peak floods during an El Niño phase was less than 70% of the geometric mean of annual peak floods during a non–El Niño phase. The relative strength of the El Niño phase, however, has, at most, a weak influence on flood magnitude. Flood exceedance probabilities for the El Niño and non–El Niño periods were calculated for all gauging stations using a three-parameter log gamma distribution. For exceedance probabilities from 0.50 to 0.02, the ratio of the El Niño to non–El Niño floods varies from greater than 10 near 32°N to less than 0.7 near 42°N. Latitude explains 76%–90% of the observed variation in the relative magnitude of El Niño versus non–El Niño floods over the range of exceedance probabilities.
Journal of Climate↗
Water quality and quantity of selected springs and seeps along the Colorado River corridor, Utah and Arizona: Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park, 1997-98
The U.S. Geological Survey, in cooperation with the National Park Service conducted an intensive assessment of selected springs along the Colorado River Corridor in Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park in 1997 and 1998, for the purpose of measuring and evaluating the water quality and quantity of the resource. This study was conducted to establish baseline data for the future evaluation of possible effects from recreational use and climate change. Selected springs and seeps were visited over a study period from 1997 to 1998, during which, discharge and on-site chemical measurements were made at selected springs and seeps, and samples were collected for subsequent chemical laboratory analysis. This interdisciplinary study also includes simultaneous studies of flora and fauna, measured and sampled coincidently at the same sites. Samples collected during this study were transported to U.S. Geological Survey laboratories in Boulder, Colorado, where analyses were performed using state-of-the-art laboratory technology. The location of the selected springs and seeps, elevation, geology, aspect, and onsite measurements including temperature, discharge, dissolved oxygen, pH, and specific conductance, were recorded. Laboratory analyses include determinations for alkalinity, aluminum, ammonium (nitrogen), antimony, arsenic, barium, beryllium, bismuth, boron, bromide, cadmium, calcium, cerium, cesium, chloride, chromium, cobalt, copper, dissolved inorganic carbon, dissolved organic carbon, dysprosium, erbium, europium, fluoride, gadolinium, holmium, iodine, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, mercury, molybdenum, neodymium, nickel, nitrate (nitrogen), nitrite (nitrogen), phosphate, phosphorus, potassium, praseodymium, rhenium, rubidium, samarium, selenium, silica, silver, sodium, strontium, sulfate, tellurium, terbium, thallium, thorium, thulium, tin, titanium, tungsten, uranium, vanadium, yttrium, ytterbium, zinc, and zirconium in these springs and seeps. Biological observations include physical setting, vegetation, invertebrate habitats, and invertebrate microhabitats.
Arizona, Utah↗
Toward linking maize chemistry to archaeological agricultural sites in the North American Southwest
Maize (Zea mays L.) was the staple domestic food crop for Ancestral Pueblo people throughout the northern American Southwest. It is thought to have been the basic food of the inhabitants of Chaco Canyon. New Mexico, a location that was a major centre of Ancestral Pueblo building and population during the 11th and early 12th centuries AD. Modern heirloom varieties of Native American corn have been difficult to grow in experimental fields in Chaco Canyon. Given an abundance of apparent storage structures in Chacoan buildings, it is possible that some corn recovered from archaeological contexts, was imported from surrounding areas. The ultimate goal of this research is to determine whether the corn in Chaco Canyon was grown locally or imported. This paper establishes the feasibility of a method to accomplish this goal. This study reports the results of using inductively coupled plasma-mass spectrometric (ICP-MS) instrumentation to determine chemical constituents of experimental fields and modern heirloom varieties of Native American corn. Analysis of 19 elements is adequate to differentiate soil and corn from three field areas. These results are promising: however, a number of problems, including post-depositional alterations in maize, remain to be solved. ?? 2001 Academic Press.
Journal of Archaeological Science↗
Distribution of inorganic mercury in Sacramento River water and suspended colloidal sediment material
The concentration and distribution of inorganic Hg was measured using cold-vapor atomic fluorescence spectrometry in samples collected at selected sites on the Sacramento River from below Shasta Dam to Freeport, CA, at six separate times between 1996 and 1997. Dissolved (ultrafiltered, 0.005 μm equivalent pore size) Hg concentrations remained relatively constant throughout the system, ranging from the detection limit (< 0.4 ng/L) to 2.4 ng/L. Total Hg (dissolved plus colloidal suspended sediment) concentrations ranged from the detection limit at the site below Shasta Dam in September 1996 to 81 ng/L at the Colusa site in January 1997, demonstrating that colloidal sediment plays an important role in the downriver Hg transport. Sequential extractions of colloid concentrates indicate that the greatest amount of Hg associated with sediment was found in the “residual” (mineral) phase with a significant quantity also occurring in the “oxidizable” phase. Only a minor amount of Hg was observed in the “reducible” phase. Dissolved Hg loads remained constant or increased slightly in the downstream direction through the study area, whereas the total inorganic Hg load increased significantly downstream especially in the reach of the river between Bend Bridge and Colusa. Analysis of temporal variations showed that Hg loading was positively correlated to discharge.
Archives of Environmental Contamination and Toxico↗
Standard reference water samples for rare earth element determinations
Standard reference water samples (SRWS) were collected from two mine sites, one near Ophir, CO, USA and the other near Redding, CA, USA. The samples were filtered, preserved, and analyzed for rare earth element (REE) concentrations (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) by inductively coupled plasma-mass spectrometry (ICP-MS). These two samples were acid mine waters with elevated concentrations of REEs (0.45–161 μg/l). Seventeen international laboratories participated in a ‘round-robin’ chemical analysis program, which made it possible to evaluate the data by robust statistical procedures that are insensitive to outliers. The resulting most probable values are reported. Ten to 15 of the participants also reported values for Ba, Y, and Sc. Field parameters, major ion, and other trace element concentrations, not subject to statistical evaluation, are provided.
Applied Geochemistry↗
Considerations in As analysis and speciation
This article summarizes recent experiences in arsenic (As) quantification, preservation, and speciation developed during AWWA Research Foundation (AWWARF) and Water Industry Technical Action Fund (WITAF) projects. The goal of this article is to alert analysts and decision-makers to potential problems in As analysis and speciation, because there appear to be several unresolved problems with routine analytical approaches. In true split drinking water samples As was quantified by three accepted analytical methods in three laboratories. The techniques used were graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation inductively coupled plasma-emission spectrometry (HG-ICP-AES). Experimental findings are organized into sections on As analysis, particulate As in water supplies, and examination of As speciation methods.
Journal of the American Water Works Association↗
Re-evaluation and extension of the scope of elements in US Geological Survey Standard Reference Water Samples
More than 100 US Geological Survey (USGS) Standard Reference Water Samples (SRWSs) were analyzed for numerous trace constituents, including Al, As, B, Ba, Be, Bi, Br, Cd, Cr, Co, Cu, I, Fe, Pb, Li, Mn, Mo, Ni, Rb, Sb, Se, Sr, Te, Tl, U, V, Zn and major elements (Ca, Mg, Na, SiO2, SO4, Cl) by inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. In addition, 15 USGS SRWSs and National Institute of Standards and Technology (NIST) standard reference material (SRM) 1641b were analyzed for mercury using cold vapor atomic fluorescence spectrometry. Also USGS SRWS Hg-7 was analyzed using isotope dilution-inductively coupled plasma mass spectrometry. The results were compared with the reported certified values of the following standard reference materials: NIST SRM 1643a, 1643b, 1643c and 1643d and National Research Council of Canada Riverine Water Reference Materials for Trace Metals SLRS-1, SLRS-2 and SLRS-3. New concentration values for trace and major elements in the SRWSs, traceable to the certified standards, are reported. Additional concentration values are reported for elements that were neither previously published for the SRWSs nor traceable to the certified reference materials. Robust statistical procedures were used that were insensitive to outliers. These data can be used for quality assurance/quality control purposes in analytical laboratories.
Analyst↗