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At least 1,369 records · Page 76Linked to original sources
USGS1989

A multiple testing approach for hazard evaluation of complex mixtures in the aquatic environment: the use of diesel oil as a model

Traditional single species toxicity tests and multiple component laboratory-scaled microcosm assays were combined to assess the toxicological hazard of diesel oil, a model complex mixture, to a model aquatic environment. The immediate impact of diesel oil dosed on a freshwater community was studied in a model pond microcosm over 14 days: a 7-day dosage and a 7-day recovery period. A multicomponent laboratory microcosm was designed to monitor the biological effects of diesel oil (1·0 mg litre −1 ) on four components: water, sediment (soil + microbiota), plants (aquatic macrophytes and algae), and animals (zooplanktonic and zoobenthic invertebrates). To determine the sensitivity of each part of the community to diesel oil contamination and how this model community recovered when the oil dissipated, limnological, toxicological, and microbiological variables were considered. Our model revealed these significant occurrences during the spill period: first, a community production and respiration perturbation, characterized in the water column by a decrease in dissolved oxygen and redox potential and a concomitant increase in alkalinity and conductivity; second, marked changes in microbiota of sediments that included bacterial heterotrophic dominance and a high heterotrophic index (0·6), increased bacterial productivity, and the marked increases in numbers of saprophytic bacteria (10 x) and bacterial oil degraders (1000 x); and third, column water acutely toxic (100% mortality) to two model taxa: Selenastrum capricornutum and Daphnia magna . Following the simulated clean-up procedure to remove the oil slick, the recovery period of this freshwater microcosm was characterized by a return to control values. This experimental design emphasized monitoring toxicological responses in aquatic microcosm; hence, we proposed the term ‘toxicosm’ to describe this approach to aquatic toxicological hazard evaluation. The toxicosm as a valuable toxicological tool for screening aquatic contaminants was demonstrated using diesel oil as a model complex mixture.

Environmental Pollution↗
USGS2016

Continued feeding on Diporeia by deepwater sculpin in Lake Huron

Monitoring changes in diets of fish is essential to understanding how food web dynamics respond to changes in native prey abundances. In the Great Lakes, Diporeia, a benthic macroinvertebrate and primary food of native benthivores, declined following the introduction of invasive Dreissena mussels and these changes were reflected in fish diets. We examined the diets of deepwater sculpin Myoxocephalus thompsonii collected in bottom trawls during 2010–2014 in the main basin of Lake Huron, and compared these results to an earlier diet study (2003–2005) to assess if their diets have continued to change after a prolonged period of Dreissena mussel invasion and declined Diporeia densities. Diporeia , Mysis , Bythotrephes , and Chironomidae were consumed regularly and other diet items included ostracods, copepods, sphaerid clams, and fish eggs. The prey-specific index of relative importance calculated for each prey group indicated that Mysis importance increased at shallow (≤55 m) and mid (64–73 m) depths, while Diporeia importance increased offshore (≥82 m). The average number of Diporeia consumed per fish increased by 10.0% and Mysis decreased by 7.5%, while the frequency of occurrence of Diporeia and Mysis remained comparable between time periods. The weight of adult deepwater sculpin (80 mm and 100 mm TL bins) increased between time periods; however, the change in weight was only significant for the 80 mm TL group ( p < 0.01). Given the historical importance of Diporeia in the Great Lakes, the examination of deepwater sculpin diets provides unique insight into the trophic dynamics of the benthic community in Lake Huron.

Environmental Biology of Fishes↗
USGS2010

The quality of our nation's waters: Nutrients in the nation's streams and groundwater, 1992-2004

National Findings and Their Implications Although the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins. Do NAWQA findings substantiate national concerns for aquatic and human health? National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or “background” levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development. Nitrate concentrations above the Federal drinking-water standard—or Maximum Contaminant Level (MCL)—of 10 milligrams per liter (mg/L, as nitrogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public‑supply wells. Are levels of nutrients in water increasing or decreasing? A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation’s most pristine streams warrants consideration. The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult. Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

Circular↗
USGS2022

Riparian spiders: Sentinels of polychlorinated dibenzo-p-dioxin and dibenzofuran-contaminated sediment

Polychlorinated dibenzo- p -dioxin and polychlorinated dibenzofuran (PCDD/F) are persistent, toxic, and bioaccumulative. Currently, PCDD/F monitoring programs primarily use fish and birds with potentially large home ranges to monitor temporal trends over broad spatial scales; sentinel organisms that provide targeted sediment contaminant information across small geographic areas have yet to be developed. Riparian orb-weaving spiders, which typically have small home ranges and consume primarily adult aquatic insects, are potential PCDD/F sentinels. Recent studies have demonstrated that spider tissue concentrations indicate the source and magnitude of dioxin-like chlorinated compounds in contaminated sediments, including polychlorinated biphenyls (PCBs). Our aim in the present study was to assess the utility of riparian spiders as sentinels for PCDD/F-contaminated sediments. We measured PCDD/F (total [Σ] and homologs) in surface sediments and spiders collected from three sites within the St. Louis River basin (Minnesota and Wisconsin, USA). We then compared (1) patterns in ΣPCDD/F concentrations between sediment and spiders, (2) the distribution of homologs within sediments and spiders when pooled across sites, and (3) the relationship between sediment and spider concentrations of PCDD/F homologs across 13 stations sampled across the three sites. The ΣPCDD/F concentrations in sediment (mean ± standard error 286 591 ± 97 614 pg/g) were significantly higher than those in riparian spiders (2463 ± 977 pg/g, p < 0.001), but the relative abundance of homologs in sediment and spiders were not significantly different. Spider homolog concentrations were significantly and positively correlated with sediment concentrations across a gradient of sediment PCDD/F contamination ( R 2 = 0.47, p < 0.001). Our results indicate that, as has been shown for other legacy organic chemicals like PCBs, riparian spiders are suitable sentinels of PCDD/F in contaminated sediment.

Minnesota, Wisconsin↗
USGS2021

Benzotriazole concentrations in airport runoff are reduced following changes in airport deicer formulations

A comparison of the presence of additives in airport deicers commonly used in the United States and in airport runoff was conducted with data collected before and after changes in deicer formulations. Three isomers of benzotriazoles (BTs)—4-methyl-1H-benzotriazole (4-MeBT), 5-methyl-1H-benzotriazole (5-MeBT), and 1H-benzotriazole (1H-BT)—are corrosion inhibitors added to some formulations of airport deicers and are reported to be a source of aquatic toxicity in streams receiving airport runoff. Concentrations of BT in aircraft deicers and anti-icing fluids (ADAF) were reduced over time but were not reduced in potassium acetate airfield-pavement deicer material (PDM) that was used throughout the study period. Streams receiving runoff from Milwaukee Mitchell International Airport, Milwaukee, Wisconsin, USA, were monitored from 2004 to 2019 for BTs, with concentrations of 4-MeBT varying from <0.35 to 4600 µg/L, 5-MeBT varying from <0.25 to 6600 µg/L, and 1H-BT varying from <0.25 to 150 µg/L. Median 4-MeBT concentrations at sites downstream from the airport decreased by approximately 74%, 5-MeBT by 69%, and 1H-BT by 82% following reduction in BTs in ADAF formulations, resulting in a reduction in the potential for aquatic toxicity in receiving streams. A change in residuals from regression analysis between freezing point depressants and BTs indicate that the reduction in BT concentrations in airport runoff was a result of BT reduction in ADAF formulations, but PDM may still be a substantial source of BTs in airport runoff. Because BTs are a source of aquatic toxicity in airport deicers, the reductions in BTs in the common deicers observed in this study can be used to demonstrate the potential for a reduction in the effects to aquatic organisms in airport runoff, resulting in greater likelihood of meeting aquatic toxicity requirements in airport stormwater permits, and potentially driving airports, airlines, and permit holders to advocate further reduction or elimination of BTs and other harmful contaminants in airport deicers.

Wisconsin↗
USGS2003

Surface-water/ground-water interaction of the Spokane River and the Spokane Valley/Rathdrum Prairie aquifer, Idaho and Washington

Historical mining in the Coeur d’Alene River Basin of northern Idaho has resulted in elevated concentrations of some trace metals (particularly cadmium, lead, and zinc) in water and sediment of Coeur d’Alene Lake and downstream in the Spokane River in Idaho and Washington. These elevated trace-metal concentrations in the Spokane River have raised concerns about potential contamination of ground water in the underlying Spokane Valley/Rathdrum Prairie aquifer, the primary source of drinking water for the city of Spokane and surrounding areas. A study conducted as part of the U.S. Geological Survey’s National Water-Quality Assessment Program examined the interaction of the river and aquifer using hydrologic and chemical data along a losing reach of the Spokane River. The river and ground water were extensively monitored over a range of hydrologic conditions at a streamflow-gaging station and 25 monitoring wells situated from 40 to 3,500 feet from the river. River stage, ground-water levels, water temperature, and specific conductance were measured hourly to biweekly. Water samples were collected on nearly a monthly basis between 1999 and 2001 from the Spokane River and were collected up to nine times between June 2000 and August 2001 from the monitoring wells. Hydrologic and chemical data indicate that the Spokane River recharges the Spokane Valley/ Rathdrum Prairie aquifer along a 17-mile reach between Post Falls, Idaho, and Spokane, Washington. Ground-water levels in the near-river aquifer (less than 300 feet from the river) indicate variably saturated conditions below the river and a ground-water flow gradient away from the losing reach of the river. Calculated monthly mean losses, during water years 2000 and 2001 along a nearly 7-mile reach between two gages, ranged from near 69 to 810 cubic feet per second. Losses generally increased with increased streamflow. However, late summer warm water temperatures also appear to be a factor as losses increased due to lower viscosity as water temperatures increased. Chemical data indicated that river recharge may influence ground-water chemistry as far as 3,000 feet from the river, but ground water within a few hundred feet of the river is most affected. Major-ion concentrations, stable isotopes, and temperature of the river and ground water from near-river wells were similar and exhibited similar temporal trends, whereas ground water from wells located farther from the river generally had higher major-ion concentrations and more stable temperatures and chemistry. Although trace-element concentrations sometimes exceeded aquatic-life criteria in the water of the Spokane River and were elevated above national median values in the bed sediment, trace-element concentrations of all river and ground-water samples were at levels less than U.S. Environmental Protection Agency drinking-water standards. The Spokane River appears to be a source of cadmium, copper, zinc, and possibly lead in the near-river ground water. Dissolved cadmium, copper, and lead concentrations generally were less than 1 microgram per liter (µg/L) in the river water and ground water. During water year 2001, dissolved zinc concentrations were similar in water from near-river wells (17-71 µg/L) and the river water (22-66 µg/L), but were less than detection levels in wells farther from the river. Arsenic, found to be elevated in ground water in parts of the aquifer, does not appear to have a river source. Although the river does influence the ground-water chemistry in proximity to the river, it does not appear to adversely affect the ground-water quality to a level of human-health concern.

Idaho;Washington↗
USGS2009

The ecological limits of hydrologic alteration (ELOHA): A new framework for developing regional environmental flow standards

The flow regime is a primary determinant of the structure and function of aquatic and riparian ecosystems for streams and rivers. Hydrologic alteration has impaired riverine ecosystems on a global scale, and the pace and intensity of human development greatly exceeds the ability of scientists to assess the effects on a river-by-river basis. Current scientific understanding of hydrologic controls on riverine ecosystems and experience gained from individual river studies support development of environmental flow standards at the regional scale. 2. This paper presents a consensus view from a group of international scientists on a new framework for assessing environmental flow needs for many streams and rivers simultaneously to foster development and implementation of environmental flow standards at the regional scale. This framework, the ecological limits of hydrologic alteration (ELOHA), is a synthesis of a number of existing hydrologic techniques and environmental flow methods that are currently being used to various degrees and that can support comprehensive regional flow management. The flexible approach allows scientists, water-resource managers and stakeholders to analyse and synthesise available scientific information into ecologically based and socially acceptable goals and standards for management of environmental flows. 3. The ELOHA framework includes the synthesis of existing hydrologic and ecological databases from many rivers within a user-defined region to develop scientifically defensible and empirically testable relationships between flow alteration and ecological responses. These relationships serve as the basis for the societally driven process of developing regional flow standards. This is to be achieved by first using hydrologic modelling to build a 'hydrologic foundation' of baseline and current hydrographs for stream and river segments throughout the region. Second, using a set of ecologically relevant flow variables, river segments within the region are classified into a few distinctive flow regime types that are expected to have different ecological characteristics. These river types can be further subclassified according to important geomorphic features that define hydraulic habitat features. Third, the deviation of current-condition flows from baseline-condition flow is determined. Fourth, flow alteration-ecological response relationships are developed for each river type, based on a combination of existing hydroecological literature, expert knowledge and field studies across gradients of hydrologic alteration. 4. Scientific uncertainty will exist in the flow alteration-ecological response relationships, in part because of the confounding of hydrologic alteration with other important environmental determinants of river ecosystem condition (e.g. temperature). Application of the ELOHA framework should therefore occur in a consensus context where stakeholders and decision-makers explicitly evaluate acceptable risk as a balance between the perceived value of the ecological goals, the economic costs involved and the scientific uncertainties in functional relationships between ecological responses and flow alteration. 5. The ELOHA framework also should proceed in an adaptive management context, where collection of monitoring data or targeted field sampling data allows for testing of the proposed flow alteration-ecological response relationships. This empirical validation process allows for a fine-tuning of environmental flow management targets. The ELOHA framework can be used both to guide basic research in hydroecology and to further implementation of more comprehensive environmental flow management of freshwater sustainability on a global scale. ?? 2009 Blackwell Publishing Ltd.

Freshwater Biology↗
USGS2020

Compounds of emerging concern detected in water samples from potable water and wastewater treatment plants and detected in water and bed-sediment samples from sites on the Trinity River, Dallas, Texas, 2009–13

The population in the Dallas-Fort Worth metropolitan area in northern Texas is rapidly growing, resulting in a rapid increase in the demand for potable water and an increase in the discharge of wastewater treatment plant effluent. An assessment of compounds of emerging concern (CECs) in samples collected at potable water and wastewater treatment plants in Dallas and downstream from Dallas in the Trinity River was completed by the U.S. Geological Survey in cooperation with the City of Dallas, Dallas Water Utilities. CECs are synthetic or naturally occurring chemicals that are not commonly monitored in the environment but can enter the environment and cause known or suspected adverse ecological or human health effects. CECs can enter the environment through nonpoint sources (for example, runoff) and point sources (for example, concentrated animal feeding operations and treated-effluent discharge from wastewater treatment plants), which can increase concentrations of CECs especially in highly populated areas. CECs include pharmaceuticals (prescription and nonprescription), steroidal hormones, stanols, sterols, detergents and detergent metabolites (hereinafter referred to as “detergents”), personal-use products, pesticides, polycyclic aromatic hydrocarbons (PAHs), flame retardants, plasticizers, and other organic compounds used in everyday domestic, agricultural, and industrial applications. The release of CECs to the environment went largely unrecognized until relatively recently. Increased loading of certain CECs to the environment, combined with advancements in laboratory analysis methods that resulted in appreciably lower detection levels, brought greater attention to the release of CECs. In addition, synthesis of new chemicals or changes in use and disposal of existing chemicals can create new sources of CECs. Some CECs are endocrine disrupting compounds (EDCs), which can elicit adverse effects on development, behavior, and reproduction of wildlife and can cause dysfunction of human and wildlife endocrine (hormone) systems. Results of studies in the United States and Europe indicate that CECs, their metabolites, and industrial, agricultural, and household wastewater products are present in the aquatic environment, water treatment plants, and septic systems. CECs, especially pharmaceuticals, are of interest because of their persistence, widespread use, and potential to cause adverse effects in humans and nontargeted organisms. There is also concern that some CECs and EDCs resist degradation of water treatment processes at potable water treatment plants (PWTPs) and wastewater treatment plants (WWTPs) and that treated-effluent discharge could contain compounds that negatively affect biota living in receiving waters. Therefore, CECs and EDCs are more likely to be detected in environmental samples collected near areas of high population density where treated effluent from WWTPs can contribute substantially to receiving waters. The U.S. Geological Survey, in cooperation with the City of Dallas, Dallas Water Utilities, evaluated the occurrence and concentrations of selected CECs in samples collected at PWTPs and WWTPs in Dallas and downstream from the Dallas-Fort Worth metropolitan area in the Trinity River, Texas, from August 2009 to December 2013. Water samples were collected at three PWTP sites, two WWTP sites, and five study sites on the Trinity River; all sites where samples were collected were in or downstream from Dallas. These water samples were analyzed for 120 CECs, including human-health pharmaceuticals (prescription and nonprescription), antibiotics, steroidal hormones, stanols, sterols, detergents, personal-use products (flavors and fragrances), pesticides and repellents, industrial wastewater compounds, disinfection compounds, PAHs, flame retardants, and plasticizers. Additionally, bed-sediment samples were collected at each of the five Trinity River sites. The bed-sediment samples were analyzed for 57 CECs. In general, the water treatment processes at PWTPs and WWTPs were effective at reducing detections and concentrations of CECs to undetectable levels or transforming the compounds into degradates that were not analyzed. There were 14 and 73 CECs detected in raw water and in untreated-influent water at PWTPs and WWTPs, respectively. Of these, 11 of the 14 CECs detected in raw-water samples and 44 of the 73 CECs detected in untreated-influent samples were not detected in finished water or in treated-effluent water samples, respectively, indicating that these compounds were removed or degraded to compounds that were not analyzed. Some CECs, however, are resistant to degradation and were detected in untreated and treated water at PWTPs and at WWTPs. The three CECs detected at PWTPs in raw-water and finished-water samples were tris(dichloroisopropyl)phosphate, benzophenone, and methyl salicylate. At WWTPs, 29 CECs were detected, including carbamazepine, sulfamethoxazole, 4-androstene-3,17- dione , 3-beta-coprostanol, acetyl-hexamethyl-tetrahydronaphthalene (AHTN), hexahydro-hexamethyl-cyclopenta-benzopyran (HHCB), 1,4-dichlorobenzene, tribromomethane, benzophenone, and tris(dichloroisopropyl)phosphate, in untreated and treated water, indicating that treatment processes likely did not remove or degrade these compounds. Of the 23 CECs detected in stream-water samples collected at 5 sites on the Trinity River in or near Dallas, 10 CECs (carbamazepine, sulfamethoxazole, caffeine, 3-beta-coprostanol, cholesterol, HHCB, benzophenone, triethyl citrate, tributyl phosphate, and tris(dichloroisopropyl)phosphate) were detected at all 5 sites. The 10 CECs detected in water samples collected at all 5 sites on the Trinity River were also detected in treated-effluent water at WWTPs. Eleven of the 57 targeted CECs were detected in bed-sediment samples collected at study sites on the Trinity River. Of these 11 CECs, only 2 (beta-sitosterol and cholesterol) were detected in bed-sediment samples at all 5 sites on the Trinity River. Nine of these 11 CECs were not detected in any water-column sample, likely because of the strong hydrophobic characteristics of these compounds. Results from water treatment plants indicate that the water treatment process is less effective for removing or degrading compounds that are engineered to be resistant to degradation. These results also indicate the presence of CECs and EDCs at locations upstream from PWTPs in Dallas. Results from Trinity River main-stem sites indicate that some compounds are naturally attenuated during transport, but a few are persistent throughout the study reach. Many CECs and EDCs are hydrophobic and were only detected in bed sediment, indicating multiple pathways through which CECs can persist in the environment. In general, concentrations of CECs in the Dallas-Fort Worth metropolitan area were similar to those found in metropolitan areas nationwide.

Texas↗
USGS2018

Uncertainty in United States coastal wetland greenhouse gas inventorying

Coastal wetlands store carbon dioxide (CO 2 ) and emit CO 2 and methane (CH 4 ) making them an important part of greenhouse gas (GHG) inventorying. In the contiguous United States (CONUS), a coastal wetland inventory was recently calculated by combining maps of wetland type and change with soil, biomass, and CH 4 flux data from a literature review. We assess uncertainty in this developing carbon monitoring system to quantify confidence in the inventory process itself and to prioritize future research. We provide a value-added analysis by defining types and scales of uncertainty for assumptions, burial and emissions datasets, and wetland maps, simulating 10 000 iterations of a simplified version of the inventory, and performing a sensitivity analysis. Coastal wetlands were likely a source of net-CO 2 -equivalent (CO 2 e) emissions from 2006–2011. Although stable estuarine wetlands were likely a CO 2 e sink, this effect was counteracted by catastrophic soil losses in the Gulf Coast, and CH 4 emissions from tidal freshwater wetlands. The direction and magnitude of total CONUS CO 2 e flux were most sensitive to uncertainty in emissions and burial data, and assumptions about how to calculate the inventory. Critical data uncertainties included CH 4 emissions for stable freshwater wetlands and carbon burial rates for all coastal wetlands. Critical assumptions included the average depth of soil affected by erosion events, the method used to convert CH 4 fluxes to CO 2 e, and the fraction of carbon lost to the atmosphere following an erosion event. The inventory was relatively insensitive to mapping uncertainties. Future versions could be improved by collecting additional data, especially the depth affected by loss events, and by better mapping salinity and inundation gradients relevant to key GHG fluxes.

Environmental Research Letters↗
USGS2004

Hazard assessment of a simulated oil spill on intertidal areas of the St. Lawrence River with SPMD-TOX

Phytoremediation in a simulated crude oil spill was studied with a “minimalistic” approach. The SPMD-TOX paradigm—a miniature passive sorptive device to collect and concentrate chemicals and microscale tests to detect toxicity—was used to monitor over time the bioavailability and potential toxicity of an oil spill. A simulated crude oil spill was initiated on an intertidal freshwater grass-wetland along the St. Lawrence River southwest of Quebec City, Quebec, Canada. Several phytoremediation treatments were investigated; to dissipate and ameliorate the spill, treatments included nutrient amendments with inorganic nitrogen sources (ammonium nitrate and sodium nitrate) and phosphate (super triple phosphate) with and without cut plants, with natural attenuation (no phytoremedial treatment) as a control. Sequestered oil residues were bioavailable in all oil-treated plots in Weeks 1 and 2. Interestingly, the samples were colored and fluoresced under ultraviolet light. In addition, microscale tests showed that sequestered residues were acutely toxic and genotoxic, as well as that they induced hepatic P 450 enzymes. Analysis of these data suggested that polycyclic aromatic hydrocarbons were among the bioavailable residues sequestered. In addition, these findings suggested that the toxic bioavailable fractions of the oil spill and degradation products dissipated rapidly over time because after the second week the water column contained no oil or detectable degradation products in this riverine intertidal wetland. SPMD-TOX revealed no evidence of bioavailable oil products in Weeks 4, 6, 8, and 12. All phytoremediation efforts appeared to be ineffective in changing either the dissipation rate or the ability to ameliorate the oil toxicity. SPMD-TOX analysis of the water columns from these riverine experimental plots profiled the occurrence, dissipation, and influence of phytoremediation on the bioavailability and toxicity of oil products (parent or degradation products).

Environmental Toxicology↗
USGS2008

Ground-water quality data in the southeast San Joaquin Valley, 2005–2006— Results from the California GAMA program

Ground-water quality in the approximately 3,800 square-mile Southeast San Joaquin Valley study unit (SESJ) was investigated from October 2005 through February 2006 as part of the Priority Basin Assessment Project of Ground-Water Ambient Monitoring and Assessment (GAMA) Program. The GAMA Statewide Basin Assessment project was developed in response to the Ground-Water Quality Monitoring Act of 2001 and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The SESJ study was designed to provide a spatially unbiased assessment of raw ground-water quality within SESJ, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 99 wells in Fresno, Tulare, and Kings Counties, 83 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study area (grid wells), and 16 of which were sampled to evaluate changes in water chemistry along ground-water flow paths or across alluvial fans (understanding wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine, and 1,2,3-trichloropropane), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, samples for matrix spikes) were collected at approximately 10 percent of the wells, and the results for these samples were used to evaluate the quality of the data for the ground-water samples. Assessment of the quality-control data resulted in censoring of less than 1 percent of the detections of constituents measured in ground-water samples. This study did not attempt to evaluate the quality of drinking water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, and (or) blended with other waters to maintain acceptable drinking-water quality. Regulatory thresholds apply to the treated water that is served to the consumer, not to raw ground water. However, to provide some context for the results, concentrations of constituents measured in the raw ground water were compared with regulatory and other health-based thresholds established by the U.S. Environmental Protection Agency and California Department of Public Health (CDPH) and thresholds established for aesthetic concerns by CDPH. Two VOCs were detected above health-based thresholds: 1,2-dibromo-3-chloropropane (DBCP), and benzene. DBCP was detected above the U.S. Environmental Protections Agency’s maximum contaminant level (MCL-US) in three grid wells and five understanding wells. Benzene was detected above the CDPH’s maximum contaminant level (MCL-CA) in one grid well. All pesticide detections were below health-based thresholds. Perchlorate was detected above its maximum contaminate level for California in one grid well. Nitrate was detected above the MCL-US in six samples from understanding wells, of which one was a public supply well. Two trace elements were detected above MCLs-US: arsenic and uranium. Arsenic was detected above the MCL-US in four grid wells and two understanding wells; uranium was detected above the MCL-US in one grid well and one understanding well. Gross alpha radiation was detected above MCLs-US in five samples; four of them understanding wells, and uranium isotope activity was greater than the MCL-US for one understanding well. Radon-222 was detected above the proposed MCL-US in all wells sampled. Total coliforms were detected in two wells and somatic coliphage was detected in one well.

California↗
USGS2002

Assessment of natural attenuation of ground-water contamination at sites FT03, LF13, and WP14/LF15, Dover Air Force Base, Delaware

Water-quality, aquifer-sediment, and hydrologic data were used to assess the effectiveness of natural attenuation of ground-water contamination at Fire Training Area Three, the Rubble Area Landfill, the Liquid Waste Disposal Landfill, and the Receiver Station Landfill in the East Management Unit of Dover Air Force Base, Delaware. These sites, which are contaminated with chlorinated solvents and fuel hydrocarbons, are undergoing long-term monitoring to determine if natural attenuation continues to sufficiently reduce contaminant concentrations to meet regulatory requirements. This report is the first assessment of the effectiveness of natural attenuation at these sites since long-term monitoring began in 1999, and follows a preliminary investigation done in 1995-96. This assessment was done by the U.S. Geological Survey in cooperation with the U.S. Air Force. Since 1995-96, additional information has been collected and used in the current assessment. The conclusions in this report are based primarily on ground-water samples collected from January through March 2000. Previous analytical results from selected wells, available geologic and geophysical well logs, and newly acquired information such as sediment organic-carbon measurements, hydraulic-conductivity measurements determined from slug tests on wells in the natural attenuation study area, and water-level measurements from surficial-aquifer wells also were used in this assessment. This information was used to: (1) calculate retardation factors and estimate contaminant migration velocities, (2) improve estimates of ground-water flow directions and inferred contaminant migration pathways, (3) better define the areal extent of contamination and the proximity of contaminants to discharge areas and the Base boundary, (4) develop a better understanding of the vertical variability of contaminant concentrations and redox conditions, (5) evaluate the effects of temporal changes on concentrations in the plumes and source areas, and (6) determine whether intrinsic biodegradation is occurring at these sites. The water-quality data indicate that intrinsic biodegradation is occurring at all three sites. The strongest indication of intrinsic biodegradation is the detection of tetrachloroethene and trichloroethene breakdown products within and down-gradient of the source areas. The patterns of electron acceptors and metabolic by-products indicate that contaminant biodegradation has changed the prevailing geochemistry of the surficial aquifer, creating the strongly reducing conditions necessary for chlorinated solvent biodegradation. Geochemical changes include depleted dissolved oxygen and elevated ferrous iron and methane levels relative to concentrations in uncontaminated zones of the surficial aquifer. At Fire Training Area Three and the Rubble Area Landfill sites, natural attenuation appears to be adequate for controlling the migration of the contaminant plumes. At the third site, the Liquid Waste Disposal and Receiver Station Landfills, the plume is larger and the uncertainty about the effectiveness of natural attenuation in reducing contaminant concentrations and controlling plume migration is greater. Ground-water data indicate, however, that U.S. Environmental Protection Agency maximum contaminant levels were not exceeded in any point-of-compliance wells located along the Base boundary. The information presented in this report led to the development of improved conceptual models for these sites, and to the recognition of four issues that are currently unclear and may need further study. These issues include delineating the areal and vertical extent of the contaminant plumes in greater detail, determining the extent of intrinsic biodegradation downgradient of the Liquid Waste Disposal and Receiver Station Landfills, determining the fate of contaminants in the ground-water discharge areas, and determining the effect of temporal variability in source concentrations and ground-water flow patterns on the plume migrating from the Liquid Waste Disposal and Receiver Station Landfills. Some of these issues have been addressed with additional data collection since the January-March 2000 sampling round.

Delaware↗
USGS2017

Expanded target-chemical analysis reveals extensive mixed-organic-contaminant exposure in USA streams

Surface water from 38 streams nationwide was assessed using 14 target-organic methods (719 compounds). Designed-bioactive anthropogenic contaminants (biocides, pharmaceuticals) comprised 57% of 406 organics detected at least once. The 10 most-frequently detected anthropogenic-organics included eight pesticides (desulfinylfipronil, AMPA, chlorpyrifos, dieldrin, metolachlor, atrazine, CIAT, glyphosate) and two pharmaceuticals (caffeine, metformin) with detection frequencies ranging 66–84% of all sites. Detected contaminant concentrations varied from less than 1 ng L –1 to greater than 10 μg L –1 , with 77 and 278 having median detected concentrations greater than 100 ng L –1 and 10 ng L –1 , respectively. Cumulative detections and concentrations ranged 4–161 compounds (median 70) and 8.5–102 847 ng L –1 , respectively, and correlated significantly with wastewater discharge, watershed development, and toxic release inventory metrics. Log 10 concentrations of widely monitored HHCB, triclosan, and carbamazepine explained 71–82% of the variability in the total number of compounds detected (linear regression; p -values: < 0.001–0.012), providing a statistical inference tool for unmonitored contaminants. Due to multiple modes of action, high bioactivity, biorecalcitrance, and direct environment application (pesticides), designed-bioactive organics (median 41 per site at μg L –1 cumulative concentrations) in developed watersheds present aquatic health concerns, given their acknowledged potential for sublethal effects to sensitive species and lifecycle stages at low ng L –1 .

Environmental Science & Technology↗
USGS1991

Aerobic biodegradation potential of subsurface microorganisms from a jet fuel-contaminated aquifer

In 1975, a leak of 83,000 gallons (314,189 liters) of jet fuel (JP-4) contaminated a shallow water-table aquifer near North Charleston, S.C. Laboratory experiments were conducted with contaminated sediments to assess the aerobic biodegradation potential of the in situ microbial community. Sediments were incubated with 14 C-labeled organic compounds, and the evolution of 14 CO 2 was measured over time. Gas chromatographic analyses were used to monitor CO 2 production and O 2 consumption under aerobic conditions. Results indicated that the microbes from contaminated sediments remained active despite the potentially toxic effects of JP-4. 14 CO 2 was measured from [ 14 C]glucose respiration in unamended and nitrate-amended samples after 1 day of incubation. Total [ 14 C]glucose metabolism was greater in 1 mM nitrate-amended than in unamended samples because of increased cellular incorporation of 14 C label. [ 14 C]benzene and [ 14 C]toluene were not significantly respired after 3 months of incubation. With the addition of 1 mM NO 3 , CO 2 production measured by gas chromatographic analysis increased linearly during 2 months of incubation at a rate of 0.099 μ mol g -1 (dry weight) day -1 while oxygen concentration decreased at a rate of 0.124 μ mol g -1 (dry weight) day -1 . With no added nitrate, CO 2 production was not different from that in metabolically inhibited control vials. From the examination of selected components of JP-4, the n -alkane hexane appeared to be degraded as opposed to the branched alkanes of similar molecular weight. The results suggest that the in situ microbial community is active despite the JP-4 jet fuel contamination and that biodegradation may be compound specific. Also, the community is strongly nitrogen limited, and nitrogen additions may be required to significantly enhance hydrocarbon biodegradation.

South Carolina↗
USGS2010

Groundwater-quality data in the Colorado River study unit, 2007: Results from the California GAMA Program

Groundwater quality in the 188-square-mile Colorado River Study unit (COLOR) was investigated October through December 2007 as part of the Priority Basin Project of the California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project was developed in response to the Groundwater Quality Monitoring Act of 2001, and the U.S. Geological Survey (USGS) is the technical project lead. The Colorado River study was designed to provide a spatially unbiased assessment of the quality of raw groundwater used for public water supplies within COLOR, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 28 wells in three study areas in San Bernardino, Riverside, and Imperial Counties. Twenty wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the Study unit; these wells are termed ‘grid wells’. Eight additional wells were selected to evaluate specific water-quality issues in the study area; these wells are termed ‘understanding wells.’ The groundwater samples were analyzed for organic constituents (volatile organic compounds [VOC], gasoline oxygenates and degradates, pesticides and pesticide degradates, pharmaceutical compounds), constituents of special interest (perchlorate, 1,4-dioxane, and 1,2,3-trichlorpropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), and radioactive constituents. Concentrations of naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water), and dissolved noble gases also were measured to help identify the sources and ages of the sampled groundwater. In total, approximately 220 constituents and water-quality indicators were investigated. Quality-control samples (blanks, replicates, and matrix spikes) were collected at approximately 30 percent of the wells, and the results were used to evaluate the quality of the data obtained from the groundwater samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a significant source of bias in the data. Differences between replicate samples were within acceptable ranges and matrix-spike recoveries were within acceptable ranges for most compounds. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, raw groundwater typically is treated, disinfected, or blended with other waters to maintain acceptable water quality. Regulatory thresholds apply to water that is served to the consumer, not to raw groundwater. However, to provide some context for the results, concentrations of constituents measured in the raw groundwater were compared to regulatory and nonregulatory health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and the California Department of Public Health (CDPH) and to thresholds established for aesthetic concerns by CDPH. Comparisons between data collected for this study and drinking-water thresholds are for illustrative purposes only and do not indicate compliance or noncompliance with those thresholds. The concentrations of most constituents detected in groundwater samples were below drinking-water thresholds. Volatile organic compounds (VOC) were detected in approximately 35 percent of grid well samples; all concentrations were below health-based thresholds. Pesticides and pesticide degradates were detected in about 20 percent of all samples; detections were below health-based thresholds. No concentrations of constituents of special interest or nutrients were detected above health-based thresholds. Most of the major and minor ion constituents sampled do not have health-based thresholds; the exception is chloride. Concentrations of chloride, sulfate, and total dissolved solids detected in some of the well samples were above the nonenforceable thresholds for aesthetic concerns. Concentrations of fluoride were detected in 5 samples (from 4 grid wells and 1 understanding well) above the maximum contaminant level for California (MCL-CA). Concentrations of most of the trace elements in samples from the COLOR study were below health-based thresholds; exceptions included arsenic above the MCL-US, boron above the notification level for California (NL-CA), iron and manganese above the secondary maximum contaminant level for California (SMCL-CA), and molybdenum and strontium above the lifetime health advisory level (HAL-US) threshold. Most detections of radioactive constituents were below health-based thresholds; exceptions were alpha, uranium, and radon radioactivity. Alpha radioactivity with 72 hour count detections occurred in four grid wells and one understanding well, and 30-day count detections in two grid wells above the MCL-US. Uranium was detected twice in grid wells above the MCL-US threshold. Also, radon-222 was detected at concentrations above the proposed MCL-US in 19 samples (14 grid and 5 understanding wells). No radon-222 was detected above the proposed MCL-US upper threshold.

California↗
USGS2008

Ground-water quality data in the Kern County Subbasin study unit, 2006— Results from the California GAMA Program

Ground-water quality in the approximately 3,000 square-mile Kern County Subbasin study unit (KERN) was investigated from January to March, 2006, as part of the Priority Basin Assessment Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001, and is being conducted by the California State Water Resources Control Board (SWRCB) in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory (LLNL). The Kern County Subbasin study was designed to provide a spatially unbiased assessment of raw (untreated) ground-water quality within KERN, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 50 wells within the San Joaquin Valley portion of Kern County. Forty-seven of the wells were selected using a randomized grid-based method to provide a statistical representation of the ground-water resources within the study unit. Three additional wells were sampled to aid in the evaluation of changes in water chemistry along regional ground-water flow paths. The ground-water samples were analyzed for a large number of man-made organic constituents (volatile organic compounds [VOCs], pesticides, and pesticide degradates), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), naturally occurring inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon) and dissolved noble gases also were measured to help identify the source and age of the sampled ground water. Quality-control samples (blanks, replicates, and laboratory matrix spikes) were collected and analyzed at approximately 10 percent of the wells, and the results for these samples were used to evaluate the quality of the data from the ground-water samples. Assessment of the quality-control information resulted in censoring of less than 0.4 percent of the data collected for ground-water samples. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, raw ground water typically is treated, disinfected, or blended with other waters to maintain acceptable water quality. Regulatory thresholds apply, not to the raw ground water, but to treated water that is served to the consumer. However, to provide some context for the results, concentrations of constituents measured in the raw ground water were compared with health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and the California Department of Public Health (CDPH), and as well as with thresholds established for aesthetic concerns (secondary maximum contaminant levels, SMCL-CA) by CDPH. VOCs and pesticides each were detected in approximately 60 percent of the grid wells, and detections of all compounds but one were below health-based thresholds. The fumigant, 1,2-dibromo-3-chloropropane (DBCP), was detected above the USEPA maximum contaminant level (MCL-US) in one sample. Detections of most inorganic constituents were also below health-based thresholds. Constituents detected above health-based thresholds include: nitrate, (MCL-US, 2 samples), arsenic (MCL-US, 2 samples), and vanadium (California notification level, NL-CA, 1 sample). All detections of radioactive constituents were below health-based thresholds, although nine samples had activities of radon-222 above the lower proposed MCL-US. Most of the samples from KERN wells had concentrations of major elements, total dissolved solids, and trace elements below the non-enforceable thresholds set for aesthetic concerns.

California↗
USGS2018

Global sea-level contribution from Arctic land ice: 1971 to 2017

The Arctic Monitoring and Assessment Program (AMAP) (AMAP, 2017) identifies the Arctic as the largest regional source of land ice to global sea-level rise in the 2003 to 2014 period. Yet, this contextualization ignores the longer perspective from in-situ records of glacier mass balance. Here, using 18 (> 55 °N latitude) glacier and ice cap mass balance series in the 1971 to 2017 period, we develop a semi-empirical estimate of annual sealevel contribution from seven Arctic regions by scaling the in-situ records to GRACE averages. We contend that our estimate represents the most accurate mass balance assessment so far available before the 1992 start of satellite altimetry. We estimate the 1971 to 2017 eustatic sea-level contribution from land ice north of ~55° N to be 23.0±12.3 mm sea-level equivalent (SLE). In all regions, the cumulative sealevel rise curves exhibit an acceleration, especially after 1988. Greenland is the source of 46% of the Arctic sea-level rise contribution (10.6±7.3 mm), followed by Alaska (5.7±2.2 mm), Arctic Canada (3.2±0.7 mm) and the Russian High Arctic (1.5±0.4 mm). Our annual results exhibit co-variability over a 43 year overlap (1971 to 2013) with the alternative dataset of Marzeion et al (2015) (M15). However, we find a 1.36x lower sea-level contribution, in agreement with satellite gravimetry. The IPCC Fifth Assessment report identified constraining the pre-satellite era sealevel budget as a topic of low scientific understanding that we address and specify sealevel contributions coinciding with IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) “present day” (2005-2015) and “recent past” (1986-2005) reference periods. We assess an Arctic land ice loss of 8.3 mm SLE during the recent past and 12.4 mm SLE during the present day.

Environmental Research Letters↗
USGS2020

North Atlantic right whale (Eubalaena glacialis) scenario planning summary report

Scenario planning provides a structured framework that can be used in strategic planning to help manage risk and prioritize actions (Schwartz 1996; Peterson et al. 2003). By providing a mechanism to communicate about complex situations, scenario planning encourages “out-of-the-box” thinking to help groups assess the impacts of plausible future scenarios on a target or resource. The outcomes from scenario planning can be used to improve management decisions, highlight data gaps, and/or identify future science priorities (Star et al. 2015; Borggaard et al. 2019). The application of scenario planning by resource management organizations (e.g., Borggaard et al. 2019; Runyon et al. 2020; Star et al. 2015) and the urgency surrounding the recovery of the critically endangered North Atlantic right whale (Eubalaena glacialis), led to a 2018 NOAA Fisheries scenario planning initiative for the species. In addition to complementing the many management and conservation efforts already underway, this initiative was designed to address the uncertainties around future anthropogenic and environmental changes and how these uncertainties may impact species recovery. We used a scenario planning framework to explore plausible future conditions for North Atlantic right whales and to develop possible options to address those conditions and improve recovery. Specific objectives were to: 1) better understand the challenges of right whale management in a changing climate; 2) identify potential research activities and recovery needs across the species’ range; 3) increase coordination and collaboration related to recovery efforts; and 4) explore how scenario planning can be used to support decisions. Using projected changes in ocean conditions coupled with anthropogenic stressors, we built four plausible future scenarios for right whales. These scenarios helped identify priority research and management actions that NOAA Fisheries and our partners can undertake to improve right whale recovery. We identified priority actions related to science, management, and partnerships including, but not limited to, 1) research on shifting spatial and temporal distributions of right whales and prey in a changing climate; 2) development of technology to further reduce impacts from human activities; 3) continuation of ongoing management efforts related to vessel traffic and fishing; and 4) continued maintenance of existing and development of new partnerships (e.g., industry engagement in problem solving). This scenario planning exercise helped prioritize North Atlantic right whale management and science needs in light of changing ocean conditions and anthropogenic impacts. It can also serve as a reference for how NOAA Fisheries and its partners can better prepare for multiple plausible futures while complementing other on-going initiatives. Priorities identified here can be considered in conjunction with implementation and monitoring actions such as with the Atlantic Large Whale Take Reduction Team (ALWTRT) and/or regional Right Whale U.S. Implementation Teams. The framework can also be repeated and improved upon as additional information becomes available to support future exercises.

Technical Memorandum↗