USGS Science⌕ Search

SEARCH · USGS Science

Results for “Toxics”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,387 records · Page 77Linked to original sources
USGS2003

Anaerobic degradation of 1,1,2,2-tetrachloroethane and association with microbial communities in a freshwater tidal wetland, Aberdeen Proving Ground, Maryland: Laboratory experiments and comparisons to field data

Defining biodegradation rates and processes is a critical part of assessing the feasibility of monitored natural attenuation as a remediation method for ground water containing organic contaminants. During 1998–2001, the U.S. Geological Survey conducted a microbial study at a freshwater tidal wetland along the West Branch Canal Creek, Aberdeen Proving Ground, Maryland, as part of an investigation of natural attenuation of chlorinated volatile organic compounds (VOCs) in the wetland sediments. Geochemical analyses and molecular biology techniques were used to investigate factors controlling anaerobic degradation of 1,1,2,2-tetrachloroethane (TeCA), and to characterize the microbial communities that potentially are important in its degradation. Rapid TeCA and daughter product degradation observed in laboratory experiments and estimated with field data confirm that natural attenuation is a feasible remediation method at this site. The diverse microbial community that seems to be involved in TeCA degradation in the wetland sediments varies with changing spatial and seasonal conditions, allowing continued effective natural attenuation throughout the year. Rates of TeCA degradation in anaerobic microcosm experiments conducted with wetland sediment collected from two different sites (WB23 and WB30) and during three different seasons (March–April 1999, July–August 1999, and October–November 2000) showed little spatial variability but high seasonal variability. Initial first-order degradation rate constants for TeCA ranged from 0.10±0.01 to 0.16±0.05 per day (halflives of 4.3 to 6.9 days) for March–April 1999 and October–November 2000 microcosms incubated at 19 degrees Celsius, whereas lower rate constants of 0±0.03 and 0.06±0.03 per day were obtained in July–August 1999 microcosms incubated at 19 degrees Celsius. Microbial community profiles showed that low microbial biomass and microbial diversity in the summer, possibly due to competition for nutrients by the wetland vegetation, could account for these unexpectedly low degradation rates. In microcosms incubated at 5 degrees Celsius, about 50 percent of the initial TeCA in solution was converted to daughter products within a 35-day incubation period, indicating that biodegradation in the wetland sediments can continue during cold winter temperatures. Initial pathways of TeCA degradation were the same in the wetland sediment microcosms regardless of the season or sediment collection site, the reduction-oxidation conditions, and the previous exposure of the sediment to contamination. Immediate and simultaneous dichloroelimination and hydrogenolysis, producing 1,2-dichloroethene (12DCE) and 1,1,2-trichloroethane (112TCA), respectively, were the initial TeCA degradation pathways in all live microcosm experiments. The production and degradation of vinyl chloride (VC), which is the most toxic of the TeCA daughter compounds, was affected by spatial and seasonal variability, reduction-oxidation condition, and pre-exposure of the wetland sediment. TeCA-amended microcosms constructed with WB30 sediment showed approximately twice as much VC production as those constructed with WB23 sediment. Results of 112TCA-amended microcosms indicated that the greater production of VC in the WB30 sediment resulted from a greater predominance of the 112TCA dichloro elimination pathway in these sediments. VC degradation also was substantially higher in microcosms constructed with WB30 sediment than those constructed with WB23 sediment, resulting in lower VC concentrations at the end of WB30 microcosms. Enrichment experiments in which microcosm slurry was amended with high initial VC concentrations showed that the spatial difference in VC degradation was negligible after prolonged incubation under methanogenic conditions. Inhibition of methanogenic activity in microcosms by addition of sulfate or of 2-bromoethanesulfonic acid inhibited production and degradation of VC. Inhibition of methanogenesis by addition of ferric iron or of 2-bromoethanesulfonic acid also completely inhibited VC degradation in VC-amended enrichment experiments. Pre-exposure to VC substantially increased degradation in VC-amended enrichment experiments. A microbial consortium, rather than one microbial species or group, likely is involved in the degradation of TeCA, as indicated by the occurrence of multiple degradation pathways and the variability in VC production and degradation. A bacterial peak at 90 base pair (bp) fragment length in terminal- restriction fragment length polymorphism (TRFLP) profiles was associated with TeCA hydrogenolysis to 112TCA, and bacterial species represented by 198 and 170 bp fragment lengths were associated with TeCA dichloroelimination to 12DCE. Dichloroelimination of 112TCA to VC was associated with increasing dominance of the 198 bp bacterial peak in March–April 1999 and October–November 2000 microcosms, whereas an 86 bp or the 170 bp bacterial peak was associated with 112TCA dichloroelimination in the summer experiment. Hydrogenolysis of 12DCE to VC was associated with a carbon dioxide-utilizing methanogen at 307 bp in the March–April 1999 and October–November 2000 microcosm experiments, whereas production of VC occurred despite low methanogen biomass and methane production in the July–August 1999 experiments. Production of VC in the absence of methane production also occurred in 12DCE-amended enrichment cultures. The exponential production of VC in the 12DCE-amended enrichment cultures after an initial lag indicated growth of a microbial species or group, possibly one of the known dehalorespiring bacteria. Molecular analyses using specific primers targeting dehalorespiring bacteria of the Dehalococcoides group (Dehalococcoides ethenogenes and Dehalococcoides sp. strain FL2) and of the acetate-oxidizing Desulfuromonas group (Desulfuromonas sp. strain BB1 and Desulfuromonas chloroethenica) showed the presence of these bacteria in microcosm slurry from site WB30 but not from site WB23. Addition of hydrogen, which is the favored substrate of Dehalococcoides, tripled VC production in 12DCE-amended enrichment cultures. VC degradation showed a marked association with an increase in the relative proportion of Methanosarcinaceae, a family of methanogens that includes all those capable of utilizing acetate as a substrate, in the total methanogen community. Half-lives for TeCA and TCE estimated from field data were in the range of 60 to 100 days, which agrees well with laboratory estimates of degradation rates considering the inherent differences in the laboratory and field systems. Both laboratory microcosm experiments and field data showed that 12DCE and VC are the predominant, persistent daughter compounds from TeCA degradation. In addition, porewater chemistry showed higher accumulation of VC in the wetland sediment at site WB30 than at site WB23, as was observed in the microcosm experiments. Molecular analyses of grab samples of surficial wetland sediment showed that all the microbial species or groups linked to TeCA degradation in the microcosm experiments were present in all sediment samples. Microbial biomass and diversity were lowest in an area of the wetland (transect C-C') where porewater VOC concentrations are highest, indicating that the higher VOC concentrations could result from lower degradation rates. The lower microbial biomass and diversity in this area could be caused by toxic effects of the contaminants, or possibly from differences in frequency and duration of tidal inundation.

Maryland↗
USGS2003

Sediment deposition and occurrence of selected nutrients, other chemical constituents, and diatoms in bottom sediment, Perry Lake, northeast Kansas, 1969–2001

A combination of bathymetric surveying and bottom-sediment coring was used to investigate sediment deposition and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 26 metals and trace elements, 15 organochlorine compounds, 1 radionuclide, and diatoms in bottom sediment of Perry Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1969 through 2001 in the original conservation-pool area of the lake was 2,470 million cubic feet (56,700 acre-feet) and 97,200 million pounds (44,100 million kilograms), respectively. The estimated sediment volume occupied about 23 percent of the original conservation-pool, water-storage capacity of the lake. Mean annual net sediment deposition since 1969 was estimated to be 3,040 million pounds (1,379 million kilograms). Mean annual sediment yield from the Perry Lake Basin was estimated to be 2,740,000 pounds per square mile (4,798 kilograms per hectare). The estimated mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Perry Lake were 7,610,000 pounds per year (3,450,000 kilograms per year) and 3,350,000 pounds per year (1,520,000 kilograms per year), respectively. The estimated mean annual yields of total nitrogen and total phosphorus from the Perry Lake Basin were 6,850 pounds per square mile per year (12.0 kilograms per hectare per year) and 3,020 pounds per square mile per year (5.29 kilograms per hectare per year), respectively. A statistically significant positive trend for total nitrogen deposition in the bottom sediment of Perry Lake was indicated. However, the trend may be due solely to analytical variance. No statistically significant trend for total phosphorus deposition was indicated. Overall, the transport and deposition of these constituents have been relatively uniform throughout the history of Perry Lake. On the basis of nonenforceable sediment-quality guidelines established by the U.S. Environmental Protection Agency, concentrations of arsenic, chromium, copper, and nickel in the bottom sediment of Perry Lake typically exceeded the threshold-effects levels, which represent the concentrations above which toxic biological effects occasionally occur. Most nickel concentrations also exceeded the probable-effects level, which represents the concentration above which toxic biological effects usually or frequently occur. Sediment concentrations of metals and trace elements were relatively uniform over time. Statistically significant positive depositional trends for arsenic and manganese and statistically significant negative depositional trends for beryllium, chromium, titanium, and vanadium were indicated. However, the trends may be due solely to analytical variance. Organochlorine compounds either were not detected or were detected at concentrations less than the threshold-effects levels. Evidence of a negative depositional trend for DDE (degradation product of DDT) was consistent with the history of DDT use. Other organochlorine compounds detected were DDD and dieldrin. Diatom occurrence in the bottom sediment of Perry Lake was dominated by species that are indicators of eutrophic (nutrient-rich) conditions. Thus, it was concluded that eutrophic conditions have existed during much of the history of Perry Lake. However, an increase in the relative percentage abundance of the oligotrophic (nutrient-poor) species, combined with the significant positive depositional trends for two oligotrophic species ( Aulacoseira islandica and Cyclotella radiosa ) and the significant negative depositional trend for one eutrophic species ( Stephanodiscus niagarae ), indicated that conditions in Perry Lake may have become less eutrophic in recent years. Notable changes in human activity within the basin included a substantial decrease in alfalfa production and a substantial increase in soybean production from 1965 to 2000. These and other changes in human activity may have had some effect on the deposition of chemical constituents and diatoms in the bottom sediment of Perry Lake. It is uncertain whether changes in human activity may account, in part, for the possibility of Perry Lake becoming less eutrophic over time as indicated by trends in the deposition of several diatom species in the lake-bed sediment.

Kansas↗
USGS2004

Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway, Adjacent to a Closed Landfill, near Roanoke, Virginia: 1999

A study was done of the effects of a closed landfill on the quality of water and streambed sediment and the benthic macroinvertebrate community of an unnamed stream and its tributary that flow through Blue Ridge Parkway lands in west-central Virginia. The primary water source for the tributary is a 4-inch polyvinyl chloride (PVC) pipe that protrudes from the slope at the base of the embankment bordering the landfill. An unusual expanse of precipitate was observed in the stream near the PVC pipe. Stream discharge was measured and water and streambed sediment samples were collected at a nearby reference site and at three sites downstream of the landfill in April and September 1999. Water samples were analyzed for major ions, nitrate, total and dissolved metals, total dissolved solids, total organic carbon, and volatile and semivolatile organic compounds, including organochlorine pesticides and polychlorinated biphenyls (PCBs). Streambed sediment samples were analyzed for total metals, total organic carbon, percent moisture, and volatile and semivolatile organic compounds, including organochlorine pesticides and PCBs. The benthic macroinvertebrate community within the stream channel also was sampled at the four chemical sampling sites and at one additional site in April and September. Each of the five sites was assessed for physical habitat quality. Water collected periodically at the PVC pipe discharge between November 1998 and November 1999 was used to conduct 48-hour acute and 7-day chronic toxicity tests using selected laboratory test organisms. Two 10-day chronic toxicity tests of streambed sediments collected near the discharge pipe also were conducted. Analyses showed that organic and inorganic constituents in water from beneath the landfill were discharged into the sampled tributary. In April, 79 percent of inorganic constituents detected in water had their highest concentrations at the site closest to the landfill; at the same site, 59 percent of inorganic constituents detected in streambed sediments were at their lowest concentration. The low dissolved-oxygen concentration and relatively low pH in ground water from beneath the landfill probably had a direct effect on the solubility of metals and other constituents, resulting in the high concentration of inorganic constituents in water, low concentration in sediment, and the development of the precipitate. Most constituents in water in April were progressively lower in concentration from the landfill site downstream. The highest concentrations for 59 percent of constituents detected in sediment were at the farthest downstream site, suggesting that the inorganic constituents came out of solution as the stream water was exposed to the atmosphere. In September, 52 percent of inorganic constituents detected in water were at their highest concentrations at the site nearest the landfill. Of inorganic constituents detected in streambed sediments in September, 60 percent were at their highest concentrations near the landfill. A storm that occurred a few days prior to the September sampling probably affected the preceding steady-state conditions and the distribution of constituents in sediment along the stream. Concentrations of many inorganic constituents in water remained elevated at the farthest downstream site in comparison to the reference site in April and September, indicating that concentrations did not return to background concentrations. In April and September, most of the 17 organic compounds detected in water, including volatile organic and semivolatile organic compounds, were collected in samples near the landfill, and most concentrations were below their respective reporting limits. Probably because of their volatility, few organic compounds were detected at sites downstream of that site. A total of 17 discrete organic compounds were detected in sediment samples in either April or September, including trichloroethene and tetrachloroethene along with their degrad

Water-Resources Investigations Report↗
USGS2001

Concentration of selected sulfonylurea, sulfonamide, and imidazolinone herbicides, other pesticides, and nutrients in 71 streams, 5 reservoir outflows, and 25 wells in the Midwestern United States, 1998

Sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IMI) herbicides are recently developed herbicides that function by inhibiting the action of a key plant enzyme, stopping plant growth, and eventually killing the plant. These compounds generally have low mammalian toxicity, but crop and non-crop plants demonstrate a wide range in sensitivity to SUs, SAs, and IMIs, with over a 10,000-fold difference in observed toxicity levels for some compounds. SUs, SAs, and IMIs are applied either pre- or post-emergence to crops commonly at 1/50th or less of the rate of other herbicides. Little is known about their occurrence, fate, or transport in surface water or ground water in the United States. To obtain information on the occurrence of SU, SA, and IMI herbicides in the Midwestern United States, 214 water samples were collected from 76 surface-water and 25 ground-water sites in 1998. These samples were analyzed for 16 SU, SA, and IMI herbicides by using highperformance liquid chromatography/mass spectrometry. Samples also were analyzed for 46 pesticides and pesticide degradation products and 13 herbicides and 10 herbicide degradates. At least 1 of the 16 SUs, SAs, or IMIs was detected at or above the method reporting limit of 0.010 microgram per liter (ug/L) in 83 percent of 133 stream samples. Imazethapyr was detected most frequently (69 percent of samples), followed by flumetsulam (65 percent of samples) and nicosulfuron (53 percent of samples). At least one SU, SA, or IMI herbicide was detected at or above the method reporting limit in 6 of 8 reservoir samples and 5 of 25 ground-water samples. SU, SA, and IMI herbicides occurred less frequently and at a fraction (often 1/50th or less) of the concentrations of other herbicides such as atrazine. Acetochlor, atrazine, cyanazine, and metolachlor were all detected in 95 percent or more of 136 stream samples.

Water-Resources Investigations Report↗
USGS1983

Preliminary appraisal of the hydrology of the Stigler area, Haskell County, Oklahoma

Bed rock in the Stigler area of southeastern Oklahoma consists principally of shale, siltstone, and sandstone of the McAlester, Savanna, and Boggy Formations of Pennsylvanian age. These rocks have been folded to form the Stigler syncline on the north and the Antioch anticline on the south. An area of several square miles is underlain by terrace deposits, mostly sandy silt, as much as 25 feet thick. Alluvium along the streams is 5 to 10 feet thick and consists mainly of sandy silt. Neither the terrace deposits nor the alluvium are hydrologically significant. Water in the bedrock is under artesian conditions. Well depths range from 34 to 235 feet and average 95 feet. The water level in most wells is less than 30 feet below the land surface. Because the rocks have minimal permeability, well yields probably are less than 5 gallons per minute. Much of the area is provided with water by a rural water district. Based on specific-conductance measurements, dissolved-solids concentrations in ground water are estimated to range from 200 to 2,500 milligrams per liter. Nor relationship between variations in specific conductance and well depth, geographic distribution, or geologic formation is apparent. Streams in the area are ephemeral and extended periods of no flow can be expected. During much of the period of record, streamflow in Taloka Creek was maintained by water pumped from an active coal mine. Water upstream from the mine area had a mean dissolved-solids concentration of 72 milligrams per liter whereas water downstream from the mine area had a mean concentration of 1,323 milligrams per liter. At times, downstream concentrations of some toxic metals exceeded the standards for drinking water set by the U.S. Environmental Protection Agency. Samples of water collected from Taloka Creek since mining ceased did not have excessive concentrations of toxic metals. Maximum suspended-sediment discharge of Taloka Creek was about 1,660 tons per day. Silt-clay particles (diameters less than 0.062 millimeter) were the dominant grain size. Observed and measured effects of surface mining for coal on the hydrologic system include (1) creation of additional water storage in the surface mine pond, (2) disruption of drainage in an area of about 1 square mile, and (3) increased mineralization of water in Taloka Creek. Other possible effects include (4) changes in permeability and storage of water in mine spoil, (5) minor changes in streamflow and runoff characteristics, and (6) temporary increase in the sediment load of Taloka Creek.

Water-Resources Investigations Report↗
USGS1984

Aldicarb-pesticide contamination of ground water in eastern Suffolk County, Long Island, New York

Aldicarb, a toxic oxime-carbamate pesticide that was believed incapable of reaching ground water, was used in potato-farming areas of eastern Suffolk County, New York during 1975-80. In 1979, aldicarb was found in substantial concentrations in ground water throughout the area. The New York State Department of Health set a limit of 7 micrograms per liter for aldicarb in drinking water. Extensive ground-water sampling into 1980 showed widespread contamination ranging from small amounts to as much as 515 micrograms per liter. In 1980, the U.S. Environmental Protection Agency banned the use of aldicarb on Long Island at the manufacturer 's request. A 1982 sampling study found aldicarb to have penetrated to about 40 feet below the water table in concentrations ranging from below detection limit to 239 micrograms per liter. Despite reputed toxicity, no instance of aldicarb poisoning on Long Island has been documented. The excessive aldicarb concentrations in the ground water of eastern Long Island may persist for decades; the duration has not been precisely determined and remains under investigation. (USGS)

Water-Resources Investigations Report↗
USGS1988

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Tulare Lake bed area, southern San Joaquin Valley, California, 1986-87

Concentrations of numerous toxic trace elements and pesticides were measured during 1986 in water, sediment, and biota from three areas near the Tulare Lake Bed, southern San Joaquin Valley, California: Kern National Wildlife Refuge, Pixley National Wildlife Refuge, and Westfarmers evaporation ponds about 5 mi west of Kern National Wildlife Refuge, to determine whether toxic constituents in agricultural-irrigation drainage pose a threat to beneficial uses of water, especially to uses by wildlife. Pesticide residues were found to be low at all three areas. Trace element concentrations were found to be comparatively low at the Kern and Pixley National Wildlife Refuge areas and high at the Westfarmers evaporation ponds. Dissolved selenium concentrations were < 1 micrograms/L (ug/L) in areas on and adjacent to the refuges, but ranged from 110 to 360 ug/L in the saline drainwater impounded in the evaporation ponds. The ratio of mean selenium concentrations in biota from Westfarmers ponds compared to biota from Kesterson National Wildlife Refuge (where adverse effects have been documented) is 5 for waterboatman, 2 for avocet liver, 1 for avocet eggs, and < 1 for widgeongrass. The low concentrations measured at Kern and Pixley National Wildlife Refuges suggest that trace elements and pesticides pose little threat to wildlife there; however, impounded subsurface drainage from agricultural irrigation does pose a threat to wildlife at the nearby Westfarmers ponds. Preliminary results of surveys conducted in 1987 indicated that there are adverse biological effects on shorebirds nesting at the ponds, although interpretation of the magnitude of the effects is premature, pending completion of ongoing studies by the U.S. Fish and Wildlife Service. (Author 's abstract)

Water-Resources Investigations Report↗
USGS1988

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the lower-Colorado River valley, Arizona, California, and Nevada, 1986-87

The Lower Colorado River Valley Irrigation Drainage Project area included the Colorado River and its environs from Davis Dam to just above Imperial Dam. Water, bottom sediment, and biota were sampled at selected locations within the study area and analyzed for selected inorganic and synthetic organic constituents that are likely to be present at toxic concentrations. With the exceptions of selenium and DDE, this study found sampling locations to be relatively free of large concentrations of toxic constituents that could be a threat to humans, fish, and wildlife. Selenium was the only inorganic constituent to exceed any existing standard, criterion, or guideline for protection of fish and wildlife resources. Concentrations of DDE in double-crested cormorants, however, exceeded the criterion of 1.0 microgram per gram established by the National Academy of Sciences and the National Academy of Engineering for DDT and its metabolites for protection of wildlife. Dissolved-selenium concentrations in water from the lower Colorado River appear to be derived from sources above Davis Dam. At this time, therefore , agricultural practices in the lower Colorado River valley do not appear to exacerbate selenium concentrations. This fact, however, does not mean that the aquatic organisms and their predators are not in jeopardy. Continued selenium loading to the lower Colorado environment could severely affect important components of the ecosystem. (Author 's abstract)

Arizona, California, Nevada↗
USGS1988

Physical, chemical, and biological characteristics of the Boise River from Veterans Memorial Parkway, Boise to Star, Idaho, October 1987 to March 1988

Physical, chemical, and biological characteristics of the Boise River were examined from October 1987 to March 1988 to determine whether trace elements in effluents from two Boise wastewater treatment facilities were detrimental to aquatic communities. Cadmium, chromium, hexavalent chromium, cyanide, lead, nickel, and silver concentrations in the Boise River were less than or near analytical detection levels and were less than chronic toxicity criteria when detectable. Arsenic, copper, and zinc were detected in concentrations less than chronic toxicity criteria. Concentrations of trace elements in bottom material generally were small and could not be attributed to effluents from wastewater treatment facilities. From October to December 1987, mean density of benthic invertebrates colonizing artificial substrates was from 6,100 individuals/substrate downstream from the West Boise wastewater treatment facility to 14,000 individuals per substrate downstream from the Lander Street wastewater treatment facility. From January to March 1988 , mean density of benthic invertebrates colonizing artificial substrates was from 7,100 individuals per substrate downstream from the West Boise facility to 10,000 individuals per substrate near Star. Insect communities upstream and downstream from the wastewater treatment facilities were strongly associated, and coeffients of community loss indicated that effluents had benign enriching effects. Distribution of mayflies indicates that trace-element concentrations in effluents did not adversely affect intolerant organisms in the Boise River. Condition factor of whitefish was significantly increased downstream from the Lander Street wastewater treatment facility and was significantly decreased downstream from the West Boise wastewater treatment facility.

Idaho↗
USGS1989

An inventory and evaluation of biological investigations that relate to stream-water quality in the upper Illinois River basin of Illinois, Indiana, and Wisconsin

Results of studies of the aquatic biology of the upper Illinois River basin provide a historical data source from which inferences can be made about changes in the quality of water in the main stem river and its tributaries. The results of biological investigations that have been conducted throughout the basin since 1900 are summarized and their relevance to stream-water-quality assessment is described, particularly their relevance to the upper Illinois River basin pilot project for the National Water Quality Assessment program. Four general categories of biological investigations were identified: Populations and community structure, chemical concentrations in tissue, organism health, and toxicity measurements. Biological investigations were identified by their location in the basin and by their relevance to each general investigation category. The most abundant literature was in the populations and community structure category. Tissue data were limited to polychlorinated biphenyls, organochlorine pesticides, dioxin, and several metals. The most cited measure of organism health was a condition factor for fish that associates body length with weight or body depth. Toxicity measurements included bioassays and the Ames Tests. The bioassays included several testing methods and test organism. (USGS)

Water-Resources Investigations Report↗
USGS1990

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the American Falls Reservoir area, Idaho, 1988-89

Increased concern about the quality of irrigation drainage and its potential effects on human health, fish, and wildlife prompted the Department of the Interior to begin a program during late 1985 to identify irrigation-induced water-quality problems that might exist in the Western States. During `988, the Task Group on Irrigation Drainage selected the American Falls Reservoir area, Idaho, for study to determine whether potentially toxic concentrations of trace elements or organochlorine compounds existed in water, bottom sediment, and biota. The 91-square mile American Falls Reservoir has a total capacity of 1.7 million acre-feet and is used primarily for irrigation-water supply and power generation. Irrigated land upstream from the reservoir totals about 550,000 acres. Total water inflow to the reservoir is about 5.8 million acre-feet per year, of which about 63 percent is from surface-water runoff, 33 percent is from ground-water discharge, and about 4 percent is from ungaged tributaries, canals, ditches, sloughs, and precipitation. Ground-water discharge to the reservoir originates, in part, from irrigation of land upstream from and adjacent to the reservoir. The 1988 water year was a drought year, and water discharge was about 34 percent less than during 1939-88. Water samples were collected during the post-irrigation (October 1987) and irrigation (July 1988) seasons and were analyzed for major ions and trace elements. Bottom-sediment samples were collected during the irrigation season and were analyzed for trace elements and organochlorine compounds. Biota samples were collected during May, June, July, and August 1988 and were analyzed for trace elements and organochlorine compounds. Dissolved-solids concentrations in water ranged from 216 to 561 milligrams per liter. The similarity of dissolved-solids concentrations between the irrigation and post-irrigation seasons can be attributed to the large volume of ground-water discharge in the study area. Most trace-element concentrations in water were near analytical reporting limits; none exceeded State or Federal water-quality standards or criteria. Trace elements that were present at all sites in analytically detectable concentrations (in micrograms per liter) included arsenic (2 to 7), boron (40 to 130), uranium (0.7 to 3.5), vanadium (1 to 6) and zinc (less than 3 to 42). The ranges of arsenic, cadmium, and mercury concentrations in water analyzed during previous investigations. Selenium concentrations ranged from less than 1 (the reporting limit) to 6 micrograms per liter and did not exceed State of Federal water-quality standards or criteria. Concentrations of most trace elements in bottom sediment were similar to geometric mean concentrations in study area soils and were within the expected 95-percent range of concentrations in soils in the Western United States. Mercury concentrations in 9 of the 18 bottom-sediment samples exceeded the 95th-percentile concentration for mercury in area soils. Selenium concentration for selenium in area soils and, in 1 sample, exceeded the upper limit of the expected 95-percent range for selenium in Western United States soils. Most organochlorine compunds in bottom sediment were lower than analytical reporting limits. Only DDE (0.2 micrograms per kilogram) and DDT (0.3 micrograms per kilogram) were detected in bottom sediment from the Portneuf River. Except for mercury and selenium, concentrations of most trace elements in biota were not considered high enough to be harmful to humans or wildlife. Some mercury concentrations in fish exceeded the U.S. Fish and Wildlife Service National Contaminant Biomonitoring Program 85th-percentile concentration and were at levels that might not be safe for human consumption, especially for pregnant women. Elevated mercury concentrations in fish-eating waterbirds, such as double-crested cormorants, indicates biomagnification in the food chain. Selenium concentrations generally were low except in mallard livers (6.6 to 41.8 micrograms per gram, dry weight). This range is within the range of selenium concentrations (19 to 43 micrograms per gram, dry weight) reported in livers of ducks from Kesterson National Wildlife Refuge, California, where waterbird deformities, moralities, and reproductive impairment were observed. Selenium concentrations in mayfly nymphs were at or near dietary concentrations (5 to 8 micrograms per gram, dry weight) that had adverse reproductive effects on mallards during laboratory toxicity studies. p,p'DDE was detected in all waterbird eggs and juvenile mallared carcasses. Highest concentrations were in cormorant eggs (0.59 to 5.70 micrograms per gram, wet weight). p,p'DDE concentrations in four of five cormorant eggs exceeded the National Academy of Sciences, National Academy of Engineering criterion for protection of aquatic wildlife (1 microgram per gram, wet weight, for p,p'DDT and its metabolites). p,p'DDE was detected in all fish samples except rainbow trout. p,p'DDE was detected in one sample of Utah suckers. No concentrations of p,p'DDE or p,p'DDT in fish exceeded the criterion for protection of aquatic life. Total PCB's were detected in all cormorant eggs and all fish samples. PCB's were not detected in other waterbird eggs. PCB concentrations in cormorant eggs (0.28 to 1.8 micro per gram, wet weight) were lower than concentrations that would be expected to cause adverse effects. Two of the three carp samples contained PCB concntrations higher than the recommended level for protection of fish and wildlife (0.4 micrograms per gram, wet weight). Eggshell thinning was noted in cormorant and mallard eggs but was not considered great enough to cause reporductive problems. Observations of the general health of fish and waterbird populations during the study indicated that the area did not appear to have a serious contaminant problem that could be associated with irrigation grainage. No waterbird or fish die-offs were observed, and nesting waterbird populations were noted to be increasing. Selenium concentrations in mallard livers, however, are of concern, as are p,p'DDE residues in cormorant eggs.

Idaho↗
USGS1993

Hydrogeology and soil gas at J-Field, Aberdeen Proving Ground, Maryland

Disposal of chemical warfare agents, munitions, and industrial chemicals in J-Field, Aberdeen Proving Ground, Maryland, has contaminated soil, groundwater and surface water. Seven exploratory borings and 38 observation wells were drilled to define the hydrogeologic framework at J-Field and to determine the type, extent, and movement of contaminants. The geologic units beneath J-Field consist of Coastal Plain sediments of the Cretaceous Patapsco Formation and Pleistocene Talbot Formation. The Patapsco Formation contains several laterally discontinuous aquifers and confining units. The Pleistocene deposits were divided into 3 hydrogeologic units--a surficial aquifer, a confining unit, and a confined aquifer. Water in the surficial aquifer flows laterally from topographically high areas to discharge areas in marshes and streams, and vertically to the underlying confined aquifer. In offshore areas, water flows from the deeper confined aquifers upward toward discharge areas in the Gunpowder River and Chesapeake Bay. Analyses of soil-gas samples showed high relative-flux values of chlorinated solvents, phthalates, and hydrocarbons at the toxic-materials disposal area, white-phosphorus disposal area, and riot-control-agent disposal area. The highest flux values were located downgradient of the toxic materials and white phosphorus disposal areas, indicating that groundwater contaminants are moving from source areas beneath the disposal pits toward discharge points in the marshes and estuaries. Elevated relative-flux values were measured upgradient and downgradient of the riot-control agent disposal area, and possibly result from soil and (or) groundwater contamination.

Water-Resources Investigations Report↗
USGS1993

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in and near Humboldt Wildlife Management Area, Churchill and Pershing Counties, Nevada, 1990-91

A reconnaissance investigation was begun in 1990 to determine whether the quality of irrigation drainage in and near the Humboldt Wildlife Management Area, Nevada, has caused or has the potential to cause harmful effects on human health, fish, and wildlife or to impair beneficial uses of water. Samples of surface and ground water, bottom sediment, and biota collected from sites upstream and downstream from the Lovelock agricultural area were analyzed for potentially toxic trace elements. Also analyzed were radioactive substances, major dissolved constitu- ents, and nutrients in water, as well as pesticide residues in bottom sediment and biota. In samples from areas affected by irrigation drainage, the following constituents equaled or exceeded baseline concentrations or recommended standards for protection of aquatic life or propagation of wildlife--in water: arsenic, boron, dissolved solids, mercury, molybdenum, selenium, sodium, and un-ionized ammonia; in bottom sediment; arsenic and uranium; and in biota; arsenic, boron, and selenium. Selenium appears to be biomagnified in the Humboldt Sink wetlands. Biological effects observed during the reconnaissance included reduced insect diversity in sites receiving irrigation drainage and acute toxicity of drain water and sediment to test organisms. The current drought and upstream consumption of water for irrigation have reduced water deliveries to the wetlands and caused habitat degradation at Humboldt Wildlife Management Area. During this investigation. Humboldt and Toulon Lakes evaporated to dryness because of the reduced water deliveries.

Water-Resources Investigations Report↗
USGS1995

Ground-water flow and the possible effects of remedial actions at J-Field, Aberdeen Proving Ground, Maryland

J-Field, located in the Edgewood Area of Aberdeen Proving Ground, Md, has been used since World War II to test and dispose of explosives, chemical warfare agents, and industrial chemicals resulting in ground-water, surface-water, and soil contami- nation. The U.S. Geological Survey finite-difference model was used to better understand ground-water flow at the site and to simulate the effects of remedial actions. A surficial aquifer and a confined aquifer were simulated with the model. A confining unit separates these units and is represented by leakance between the layers. The area modeled is 3.65 mi2; the model was constructed with a variably spaced 40 X 38 grid. The horizontal and lower boundaries of the model are all no-flow boundaries. Steady-state conditions were used. Ground water at the areas under investigation flows from disposal pit areas toward discharge areas in adjacent estuaries or wetlands. Simulations indicate that capping disposal areas with an impermeable cover effectively slows advective ground water flow by 0.7 to 0.5 times. Barriers to lateral ground-water flow were simulated and effectively prevented the movement of ground water toward discharge areas. Extraction wells were simulated as a way to contain ground-water contamination and to extract ground water for treatment. Two wells pumping 5 gallons per minute each at the toxic-materials disposal area and a single well pumping 2.5 gallons per minute at the riot-control-agent disposal area effectively contained contamination at these sites. A combi- nation of barriers to horizontal flow east and south of the toxic-materials disposal area, and a single extraction well pumping at 5 gallons per minute can extract contaminated ground water and prevent pumpage of marsh water.

Water-Resources Investigations Report↗
USGS1996

Water quality, bed-sediment quality, and simulation of potential contaminant transport in Foster Creek, Berkeley County, South Carolina, 1991-93

Foster Creek, a freshwater tidal creek in Berkeley County, South Carolina, is located in an area of potential contaminant sources from residential, commercial, light industrial, and military activities. The creek is used as a secondary source of drinking water for the surrounding Charleston area. Foster Creek meets most of the freshwater- quality requirements of State and Federal regulatory agencies, but often contains low concentrations of dissolved oxygen and has been characterized as eutrophic. Investigations of water- and bed-sediment quality were made between 1991 and 1993 to assess the effects of anthropogenic sources of contamination on Foster Creek. Low-flow surface-water samples were generally free of toxic compounds with the exception of laboratory artifacts and naturally occurring trace metals. Storm-runoff samples generally contained very low concentrations (near detection limits) of a small number of volatile and semivolatile organics and naturally occurring trace metals. Concentrations of toxic compounds in excess of current (1995) South Carolina Department of Health and Environmental Control and U.S. Environmental Protection Agency regulations were not detected in surface-water samples collected from Foster Creek. Chemical analyses of streambed sediments indicated minimal anthropogenic effects on sediment quality. The particle-tracking option of the U.S. Geological Survey one-dimensional unsteady-flow model (BRANCH) indicated that as the simulated volume of rainfall runoff increased in the Foster Creek Basin, simulated particles in Foster Creek were transported greater distances. Simulating flow through the Bushy Park Dam (also known as Back River Dam) had little effect on particle movement in Foster Creek. Simulating typical withdrawal rates at a water-supply intake resulted in a slight attraction of particles toward the intake during conditions of relatively low runoff. These withdrawals had a greater influence on particles downstream of the intake than on those upstream of the intake. Simulations confirmed earlier findings which suggested that the creek would not flush during baseflow conditions, with the exception of the lower 1-mile reach, where flushing results from tidal movements. According to the simulations, Foster Creek will fully flush if a 2-year, 7-day storm occurs. Flushing appears to be affected more by the total volume of storm runoff than by typical municipal withdrawals or tidal effects.

South Carolina↗
USGS1996

Summary of biological investigations relating to water quality in the Western Lake Michigan Drainages, Wisconsin and Michigan

This report summarizes aquatic biological studies relevant to water-quality assessment that have been done in the Western Lake Michigan Drainages from 1891 to 1996. The objective of the summary was to compile sources of biological data for the U.S. Geological Survey's National Water-Quality Assessment Program. The studies are divided into four categories: (1) populations and community structure of aquatic biota, (2) health of aquatic biota, (3) chemical concentrations in tissues of aquatic biota, and (4) toxicity tests by use of aquatic biota. Studies are further categorized by subbasin, spatial scale (regional or local), types of biota, and, if applicable, effect or contaminant investigated. For the purposes of this report, the study area is divided into five subbasins. The subbasins, from north to south, are (1) the Ford/Escanaba Subbasin in Michigan's Upper Peninsula, and in Wisconsin, (2) the Menominee/ Oconto/Peshtigo Subbasin, (3) the Fox/Wolf Subbasin, (4) the Sheboygan/Manitowoc/Twin Subbasin, and (5) the Milwaukee Subbasin. Most biological studies related to waterquality conditions in the Western Lake Michigan Drainages have focused on populations and community structure of aquatic biota. Chemical concentrations in tissues of aquatic biota have been the next most common area of research. Our review suggests a paucity of data related to the health of all types of aquatic biota, especially amphibians, invertebrates, and reptiles; toxicity studies also were relatively uncommon. Overall, organisms primarily studied have been fish and invertebrates, although birds are most frequently examined in studies of organism health. The Fox/ Wolf Subbasin has been the focus of many more studies than the other subbasins, most likely because of the greater extent and severity of known water-quality problems in the Lower Fox River/Green Bay area over the past several decades and because it is the largest subbasin. Studies in the other subbasins are needed to adequately assess the water quality of these areas.

Michigan, Wisconsin↗
USGS1997

Natural attenuation of chlorinated volatile organic compounds in a freshwater tidal wetland, Aberdeen Proving Ground, Maryland

Ground-water contaminant plumes that are flowing toward or currently discharging to wetland areas present unique remediation problems because of the hydrologic connections between ground water and surface water and the sensitive habitats in wetlands. Because wetlands typically have a large diversity of microorganisms and redox conditions that could enhance biodegradation, they are ideal environments for natural attenuation of organic contaminants, which is a treatment method that would leave the ecosystem largely undisturbed and be cost effective. During 1992-97, the U.S. Geological Survey investigated the natural attenuation of chlorinated volatile organic compounds (VOC's) in a contaminant plume that discharges from a sand aquifer to a freshwater tidal wetland along the West Branch Canal Creek at Aberdeen Proving Ground, Maryland. Characterization of the hydrogeology and geochemistry along flowpaths in the wetland area and determination of the occurrence and rates of biodegradation and sorption show that natural attenuation could be a feasible remediation method for the contaminant plume that extends along the West Branch Canal Creek. The aquifer, which received contaminants in the past from sources that were located upgradient of the current eastern boundary of the wetland, is about 40 to 45 feet thick in the study area. The overlying wetland sediments consist of two distinct layers that have a combined thickness of about 6 to 12 feet--an upper unit of peat and a lower unit of silty to sandy clay or clayey sand. Head distributions show strong vertical gradients, and flow directions are predominantly upward through the wetland sediments. Tidal fluctuations, however, cause some reversals in ground-water-flow directions and changes in discharge locations, which affect the distribution and transport of contaminants. The average linear velocity of ground water is estimated to be about 2 to 3 feet per year along vertical flow lines in the wetland area, and the total ground-water discharge along a 1-foot-wide strip of the wetland extending from the eastern wetland boundary to the creek is in the range of 0.13 to 0.25 feet squared per day. The major parent contaminants in the aquifer were trichloroethylene (TCE); 1,1,2,2-tetrachloroethane (PCA); carbon tetrachloride (CT); and chloroform (CF). The aquifer was typically aerobic, but ground water in the wetland sediments became increasingly anaerobic along the upward flow direction. Iron-reducing conditions were predominant in the lower wetland sediment unit composed of clayey sand and silt, and methanogenesis was predominant in an upper unit composed of peat. Total concentrations of VOC's and the relative proportions of parent compounds to anaerobic daughter products changed substantially as the contaminants were transported upward through these changing redox environments. Concentrations of the parent compounds TCE and PCA ranged from about 100 to 2,000 micrograms per liter in the aquifer beneath the wetland, whereas concentrations of daughter products were low or undetectable. In contrast, the parent compounds commonly were not detected in ground water in the wetland sediments, but the daughter compounds 1,2- dichloro-ethylene (12DCE), vinyl chloride (VC), 1,1,2-trichloroethane (112TCA), and 1,2-dichloroethane (12DCA) were observed. 12DCE and VC were the dominant daughter products in the wetland sediments, even where PCA was the primary parent contaminant discharging to the wetland. The presence of these daughter products in water in the wetland sediments indicates that TCE and PCA are degraded by reductive dechlorination reactions in the naturally anaerobic wetland sediments. Although production of daughter products was observed, total concentrations of the VOC's decreased upward through the 6- to 12-feet-thick wetland sediments and were less than 5 micrograms per liter near the surface. The daughter products are apparently further degraded by these anaerobic processes to non-chlorinated, non-toxic endproducts, or are removed by other attenuation processes such as aerobic degradation or volatilization. Several sets of anaerobic microcosms, some amended with TCE concentrations of 400 or 990 micrograms per liter (3.0 or 7.5 micromoles per liter) and one amended with PCA concentration of 480 micrograms per liter (2.9 micromoles per liter), were constructed in the laboratory using wetland sediment and ground water from the study area. These microcosm experiments confirmed field observations that 12DCE and VC are the dominant daughter products from anaerobic biodegradation of both TCE and PCA. Production of 112TCA and 12DCA also was observed in the PCA-amended microcosms, but concentrations were lower than those of 12DCE and VC. These results indicate that degradation of PCA occurs through both hydrogenolysis and dichloroelimination pathways under anaerobic conditions. Daughter products were not observed in sterile controls, except for relatively low concentrations of 12DCE in the PCA-amended controls, suggesting that the reactions were predominantly microbially mediated. Parent and daughter concentrations in the microcosms decreased to less than 5 micrograms per liter in less than 34 days under methanogenic conditions, thus showing extremely rapid biodegradation rates in these organic-rich wetland sediments. Maximum potential rate constants for biodegradation of TCE and PCA, which were calculated from the microcosm exper-iments assuming first-order degradation rates, ranged from 0.10 to 0.31 per day under methanogenic conditions, corresponding to half-lives of 2 to 7 days. The rate constant for TCE biodegradation under sulfate-reducing conditions was 0.045 West Branch, Aberdeen Proving Ground, Maryland 3 per day (half-life of 15 days), which is lower than under methanogenic conditions. These estimated rate constants for the wetland sediments are two to three orders of magnitude higher than those reported in the literature for TCE biodegradation in microcosms constructed with sandy aquifer sediments. Aerobic biodegradation rates for cis-12DCE, trans-12DCE, and VC were in the same range as those measured for TCE and PCA under anaerobic conditions in microcosm experiments. Thus, production of these daughter products by anaerobic biodegradation of TCE and PCA could be balanced by their consumption where oxygen is available in the wetland sediment, such as near roots and land surface. In the aerobic microcosm experiments, biodegradation of cis-12DCE, trans-12DCE, and VC occurred only if methane consumption occurred, indicating that methanotrophs were involved in the process. Aerobic biodegradation was fastest for vinyl chloride and slowest for TCE in the microcosm experiments. These results agree with other laboratory and field studies that have shown faster degradation by methane-utilizing cultures when the compounds are less halogenated. Equilibrium sorption isotherms were measured in 24-hour batch tests and used to estimate distribution coefficients ( K d 's) to describe the ratios of sorbed to aqueous concentrations of PCA and the daughter products cis-12DCE, trans-12DCE, and VC. The estimated K d's for PCA, cis-12DCE, trans-12DCE, and VC were about 2.3, 1.8, 2.4, and 1.3 liters per kilogram of sediment, respectively. Sorbed concentrations of PCA, cis-12DCE, and trans-12DCE in the wetland sediments, therefore, would be expected to be about twice the concentration measured in the water, whereas sorbed concentrations of VC would not be much greater than the aqueous concentrations. Coefficients of retardation, which were calculated using the K d 's and an advective flow velocity of about 2 feet per year, indicate that sorption alone would cause the movement of the contaminants in the wetland sediments to be 6 to 10 times slower than the advective ground-water flow. Biodegradation and sorption, therefore, are significant natural attenuation mechanisms for chlorinated hydrocarbons in these wetland sediments. The relatively thin layers of wetland sediments are critical in reducing contaminant concentrations and toxicity of the ground water before it discharges to the wetland surface and the creek, and natural attenuation in the wetland sediments could be an effective remediation method for the ground-water contaminants.

Maryland↗
USGS1997

Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

Because of concerns expressed by the U.S. Congress and the environmental community, the Department of the Interior began a program in late 1985 to identify the nature and extent of water-quality problems induced by irrigation that might exist in the western States. Surface water, bottom sediment, and biota were collected from March through September 1995 along the lower Colorado River and in agricultural drains at nine sites in the Yuma Valley, Arizona, and analyzed for selected inorganic and organic constituents. Analyses of water, bottom sediment, and biota were completed to determine if irrigation return flow has caused, or has the potential to cause, harmful effects on human health, fish, and wildlife in the study area. Concentrations of dissolved solids in surface-water samples collected in March generally did not vary substantially from surface-water samples collected in June. Concentrations of dissolved solids ranged from 712 to 3,000 milligrams per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 500 milligrams per liter for drinking water. Concentrations of chloride in 9 of 18 water samples and concentrations of sulfate in 16 of 18 water samples exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 250 milligrams per liter for drinking water. Calcium and sodium were the dominant cations, and chloride and sulfate were the dominant anions. The maximum selenium concentration of 8 micrograms per liter exceeded the U.S. Environmental Protection Agency aquatic-life chronic criterion of 5 micrograms per liter. Concentrations of lead in 7 of 18 water samples and concentrations of mercury in 4 of 18 water samples exceeded the aquatic-life cronic criteria of 3.2 and 0.012 micrograms per liter, respectively. Concentrations of antimony, beryllium, cadmium, and silver in the water samples were below analytical reporting limits. Arsenic was detected in 3 of 9 bottom-sediment samples, and concentrations ranged from 11 to 16 micrograms per gram. Concentrations ofaluminum, beryllium, boron, copper, lead, and zinc were highest in samples from Main Drain at southerly international boundary near San Luis, Arizona. Selenium was detected in all bottom-sediment samples, and concentrations ranged from 0.1 to 0.7 micrograms per gram. Concentrations of cadmium, europium, homium, mercury, molybdenum, silver, tantalum, tin, and uranium were below analytical reporting limits in the bottom-sediment samples. Concentrations of trace elements in bottom-sediment samples were within the ranges found in a study of soils of the western United States and did not indicate a significant accumulation of these constituents. p,p'Dichlorodiphenyldichloroethylene (commonly referred to as p,-p'-DDE) was detected in one bottom-sediment sample at a concentration of 1.4 micrograms per gram. No other organochlorine compounds were detected in the bottom-sediment samples. DDE was present in all fish and bird samples. Almost one-half of the fish samples contained DDE residues that were two times higher than the mean calculated for a national study in 1984-85. Twenty-tree percent of the fish contained more than three times the national mean. Fish from downstream parts of the Main Drain had the highest concentrations of DDE. Although concentrations of DDE in fish and in bird carcasses and eggs were above background levels, residues generally were below thresholds associated with chronic poisoning and reproductive problems in figh and wildlife. Concentrations of 18 trace elements were detected in cattail (Typha sp.) roots, freshwater clam (Corbicula fluminea), fish, and bird samples. Selenium in most fish and in livers of red-winged (Agelaius phoeniceus) and yellow-headed (Xanthocephalus xanthocephalus) blackbirds was above background concentrations but below toxic concentrations. In contrast, selenium was present in a killdeer (Charadrium vociferus) liver sample at potentially toxic con

Water-Resources Investigations Report↗