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At least 343 records · Page 19Linked to original sources
USGS2018

Watershed export of fine sediment, organic carbon, and chlorophyll-a to Chesapeake Bay: Spatial and temporal patterns in 1984–2016

Chesapeake Bay has long experienced nutrient enrichment and water clarity deterioration. This study provides new quantification of loads and yields for sediment (fine and coarse grained), organic carbon (total, dissolved, and particulate), and chlorophyll-a from the monitored nontidal Chesapeake Bay watershed (MNTCBW), all of which are expected to drive estuarine water clarity. We conducted an integrated analysis of nine major tributaries to the Bay to understand spatial and temporal export patterns over the last thirty years (1984–2016). In terms of spatial pattern, export of these constituents from the MNTCBW was strongly dominated (~ 90%) by the three largest tributaries (i.e., Susquehanna, Potomac, and James). Among the nine tributaries, the ranking of constituent export generally follows the order of their watershed sizes, with other factors such as land use and reservoir playing important roles in some exceptions. In terms of partitioning, suspended sediment (SS) export was dominated by fine-grained sediment (SS fine ) in all nine tributaries; overall, ~ 90% of the MNTCBW SS is SS fine . Total organic carbon (TOC) export was dominated by dissolved organic carbon (DOC) in all tributaries except Potomac River; overall, ~ 60% of the MNTCBW TOC is DOC. A comparison with literature shows that the MNTCBW SS and TOC yields were ~ 80% and ~ 60% of the respective medians of worldwide watersheds. In terms of temporal pattern, flow-normalized yields from the MNTCBW show overall increases in SS (both long-term [1984–2016] and short-term [2004–2016]), SS fine (long-term and short-term), TOC (long-term), and chlorophyll-a (short-term). The rises in SS, SS fine , and TOC were largely driven by Susquehanna River where Conowingo Reservoir's trapping efficiency has greatly diminished in the last twenty years. Overall, these new results on the status and trends of sediment, organic carbon, and chlorophyll-a provide the foundation for building potential linkages between riverine inputs and estuarine water clarity patterns.

Chesapeake Bay watershed↗
USGS2018

Surrounding land cover types as predictors of palustrine wetland vegetation quality in conterminous USA

The loss of wetland habitats and their often-unique biological communities is a major environmental concern. We examined vegetation data obtained from 380 wetlands sampled in a statistical survey of wetlands in the USA. Our goal was to identify which surrounding land cover types best predict two indices of vegetation quality in wetlands at the regional scale. We considered palustrine wetlands in four regions (Coastal Plains, North Central East, Interior Plains, and West) in which the dominant vegetation was emergent, forested, or scrub-shrub. For each wetland, we calculated weighted proportions of eight land cover types surrounding the area in which vegetation was assessed, in four zones radiating from the edge of the assessment area to 2 km. Using Akaike's Information Criterion, we determined the best 1-, 2- and 3-predictor models of the two indices, using the weighted proportions of the land cover types as potential predictors. Mean values of the two indices were generally higher in the North Central East and Coastal Plains than the other regions for forested and emergent wetlands. In nearly all cases, the best predictors of the indices were not the dominant surrounding land cover types. Overall, proportions of forest (positive effect) and agriculture (negative effect) surrounding the assessment area were the best predictors of the two indices. One or both of these variables were included as predictors in 65 of the 72 models supported by the data. Wetlands surrounding the assessment area had a positive effect on the indices, and ranked third (33%) among the predictors included in supported models. Development had a negative effect on the indices and was included in only 28% of supported models. These results can be used to develop regional management plans for wetlands, such as creating forest buffers around wetlands, or to conserve zones between wetlands to increase habitat connectivity.

Science of the Total Environment↗
USGS2018

Wetlands receiving water treated with coagulants improve water quality by removing dissolved organic carbon and disinfection byproduct precursors

Constructed wetlands are used worldwide to improve water quality while also providing critical wetland habitat. However, wetlands have the potential to negatively impact drinking water quality by exporting dissolved organic carbon (DOC) that upon disinfection can form disinfection byproducts (DBPs) like trihalomethanes (THMs) and haloacetic acids (HAAs). We used a replicated field-scale study located on organic rich soils in California's Sacramento-San Joaquin Delta to test whether constructed flow-through wetlands which receive water high in DOC that is treated with either iron- or aluminum-based coagulants can improve water quality with respect to DBP formation. Coagulation alone removed DOC (66–77%) and THM (67–70%) precursors, and was even more effective at removing HAA precursors (77–90%). Passage of water through the wetlands increased DOC concentrations (1.5–7.5 mg L − 1 ), particularly during the warmer summer months, thereby reversing some of the benefits from coagulant addition. Despite this addition, water exiting the wetlands treated with coagulants had lower DOC and DBP precursor concentrations relative to untreated source water. Benefits of the coagulation-wetland systems were greatest during the winter months (approx. 50–70% reduction in DOC and DBP precursor concentrations) when inflow water DOC concentrations were higher and wetland DOC production was lower. Optical properties suggest DOC in this system is predominantly comprised of high molecular weight, aromatic compounds, likely derived from degraded peat soils.

Science of the Total Environment↗
USGS2018

Juvenile coho salmon growth and health in streams across an urbanization gradient

Expanding human population and urbanization alters freshwater systems through structural changes to habitat, temperature effects from increased runoff and reduced canopy cover, altered flows, and increased toxicants. Current stream assessments stop short of measuring health or condition of species utilizing these freshwater habitats and fail to link specific stressors mechanistically to the health of organisms in the stream. Juvenile fish growth integrates both external and internal conditions providing a useful indicator of habitat quality and ecosystem health. Thus, there is a need to account for ecological and environmental influences on fish growth accurately. Bioenergetics models can simulate changes in growth and consumption in response to environmental conditions and food availability to account for interactions between an organism's environmental experience and utilization of available resources. The bioenergetics approach accounts for how thermal regime, food supply, and food quality affect fish growth. This study used a bioenergetics modeling approach to evaluate the environmental factors influencing juvenile coho salmon growth among ten Pacific Northwest streams spanning an urban gradient. Urban streams tended to be warmer, have earlier emergence dates and stronger early season growth. However, fish in urban streams experienced increased stress through lower growth efficiencies, especially later in the summer as temperatures warmed, with as much as a 16.6% reduction when compared to fish from other streams. Bioenergetics modeling successfully characterized salmonid growth in small perennial streams as part of a more extensive monitoring program and provides a powerful assessment tool for characterizing mixed life-stage specific responses in urban streams.

Science of the Total Environment↗
USGS2018

Brook trout distributional response to unconventional oil and gas development: Landscape context matters

We conducted a large-scale assessment of unconventional oil and gas (UOG) development effects on brook trout ( Salvelinus fontinalis ) distribution. We compiled 2231 brook trout collection records from the Upper Susquehanna River Watershed, USA. We used boosted regression tree (BRT) analysis to predict occurrence probability at the 1:24,000 stream-segment scale as a function of natural and anthropogenic landscape and climatic attributes. We then evaluated the importance of landscape context (i.e., pre-existing natural habitat quality and anthropogenic degradation) in modulating the effects of UOG on brook trout distribution under UOG development scenarios. BRT made use of 5 anthropogenic (28% relative influence) and 7 natural (72% relative influence) variables to model occurrence with a high degree of accuracy [Area Under the Receiver Operating Curve (AUC) = 0.85 and cross-validated AUC = 0.81]. UOG development impacted 11% ( n = 2784) of streams and resulted in a loss of predicted occurrence in 126 (4%). Most streams impacted by UOG had unsuitable underlying natural habitat quality ( n = 1220; 44%). Brook trout were predicted to be absent from an additional 26% ( n = 733) of streams due to pre-existing non-UOG land uses (i.e., agriculture, residential and commercial development, or historic mining). Streams with a predicted and observed (via existing pre- and post-disturbance fish sampling records) loss of occurrence due to UOG tended to have intermediate natural habitat quality and/or intermediate levels of non-UOG stress. Simulated development of permitted but undeveloped UOG wells ( n = 943) resulted in a loss of predicted occurrence in 27 additional streams. Loss of occurrence was strongly dependent upon landscape context, suggesting effects of current and future UOG development are likely most relevant in streams near the probability threshold due to pre-existing habitat degradation.

New York, Pennsylvania↗
USGS2018

Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May–July 2016 and analyzed for concentrations of FIOs (total coliforms and E . coli ) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E . coli , norovirus, and Salmonella . Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E . coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs.

Pennsylvania↗
USGS2018

A semi-arid river in distress: Contributing factors and recovery solutions for three imperiled freshwater mussels (Family Unionidae) endemic to the Rio Grande basin in North America

Freshwater resources in arid and semi-arid regions are in extreme demand, which creates conflicts between needs of humans and aquatic ecosystems. The Rio Grande basin in the southwestern United States and northern Mexico exemplifies this issue, as much of its aquatic biodiversity is in peril as a result of human activities. Unionid mussels have been disproportionately impacted, though the specific factors responsible for their decline remain largely unknown. This is problematic because the Rio Grande basin harbors one federally endangered unionid mussel ( Popenaias popeii , Texas Hornshell) plus two other mussel species ( Potamilus metnecktayi , Salina Mucket; and Truncilla cognata , Mexican Fawnsfoot), which are also being considered for listing under the U.S. Endangered Species Act. To date, surveys for these species have not corrected for variability in detection so current range estimates may be inaccurate. Using single occupancy-modeling to estimate detection and occupancy at 115 sites along ~800 river kilometers of the Rio Grande in Texas, we found that detection probabilities were relatively high, indicating that our survey design was efficient. In contrast, the estimated occupancy was low, indicating that our focal species were likely rare within the Rio Grande drainage. In general, the predicted occupancy of our focal species was low throughout their respective ranges, indicating possible range declines. A comparison of currently occupied ranges to presumptive ranges underscores this point. The best-approximating models indicated that occupancy was influenced by habitat, water quantity and quality, and proximity to large-scale human activities, such as dams and major urban centers. We also discuss a series of conservation options that may not only improve the long-term prognosis of our focal species but also other aquatic taxa.

Rio Grande basin↗
USGS2018

Methane in groundwater from a leaking gas well, Piceance Basin, Colorado, USA

Site-specific and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase. Water-level and methane-isotopic data, and video logs from a deep monitoring well, indicated that a shale confining layer ~125 m below the zone of contamination was an effective barrier to upward migration of water and gas. The gas well, located 27 m from the contaminated monitoring well, had ~1000 m of uncemented annular space behind production casing that was the likely pathway through which deep gas migrated into the shallow aquifer. Measurements of soil gas near the gas well showed no evidence of methane emissions from the soil to the atmosphere even though methane concentrations in shallow groundwater (16 to 20 mg/L) were above air-saturation levels. Methane degassing from the water table was likely oxidized in the relatively thick unsaturated zone (~18 m), thus rendering the leak undetectable at land surface. Drilling and plugging records for oil and gas wells in Colorado and proxies for depth to groundwater indicated thousands of oil and gas wells were drilled and plugged in the same timeframe as the implicated gas well, and the majority of those wells were in areas with relatively large depths to groundwater. This study represents one of the few detailed subsurface investigations of methane leakage from a plugged and abandoned gas well. As such, it could provide a useful template for prioritizing and assessing potentially leaking wells, particularly in cases where the leakage does not manifest itself at land surface.

Colorado↗
USGS2018

Dissipation of polyoxyethylene tallow amine (POEA) and glyphosate in an agricultural field and their co-occurrence on streambed sediments

The environmental fate of polyoxyethylene tallow amine (POEA), an additive in glyphosate herbicide formulations, has not been studied. This study examined the dissipation of POEA; glyphosate; and aminomethylphosphonic acid (AMPA), a degradation product of glyphosate, in the top 45 cm of soil from an agricultural field where glyphosate was applied. The concentration of these compounds was also analyzed in bed sediment samples from watersheds in agricultural and urban areas from six states (Georgia, Hawaii, Iowa, Mississippi, North Carolina, South Carolina). The field studies show that POEA, glyphosate, and AMPA persist on the soil from planting season to planting season but dissipate over time with little migration into deeper soil. POEA, glyphosate, and AMPA were found on the bed sediment samples in urban and agricultural watersheds.

Georgia, Hawaii, Iowa, Mississippi, North Carolina↗
USGS2018

Bioactive contaminants of emerging concern in National Park waters of the northern Colorado Plateau, USA

Pharmaceuticals and personal care products (PPCPs), wastewater indicators (WWIs), and pesticides (herein, Contaminants of Emerging Concern [CECs]) have been documented in surface waters throughout the world and have associated risks to aquatic life. While much research has focused on temperate and urbanized watersheds, less is known about CEC presence in semi-arid landscapes, where water availability is limited and populations are low. CEC presence in water and sediment is reported for 21 sites in eight U.S. national parks in the northern Colorado Plateau region. From 2012 to 2016, at least one PPCP and/or WWI was detected at most sites on over half of sampling visits, indicating that CECs are not uncommon even in isolated areas. CEC detections were generally fewer and at lower concentrations than in urbanized or agricultural watersheds. Consistent with studies from other U.S. regions, the most frequently detected CECs in this study include DEET, caffeine, organophosphorus flame retardants, and bisphenol A in water and fecal indicators and polycyclic aromatic hydrocarbons in sediment. Maximum concentrations in this study were generally below available water quality benchmarks, sediment quality guidelines, and risk assessment thresholds associated with vertebrates. Additional work is needed to assess the potential activity of hormones, which had high reporting limits in our study, and potential bioactivity of environmental concentrations for invertebrates, microbial communities, and algae. Potential sources of CEC contamination include upstream wastewater effluent discharges and National Park Service invasive-plant-control herbicide applications. CEC occurrence patterns and similarities between continuous and isolated flow locations suggest that direct contamination from individual visitors may also occur. While our data indicate there is little aquatic health risk associated with CECs at our sites, our results demonstrate the ubiquity of CECs on the landscape and a continued need for public outreach concerning resource-use ethics and the potential effects of upstream development.

Colorado Plateau↗
USGS2018

Inferring watershed hydraulics and cold-water habitat persistence using multi-year air and stream temperature signals

Streams strongly influenced by groundwater discharge may serve as “climate refugia” for sensitive species in regions of increasingly marginal thermal conditions. The main goal of this study is to develop paired air and stream water annual temperature signal analysis techniques to elucidate the relative groundwater contribution to stream water and the effective groundwater flowpath depth. Groundwater discharge to streams attenuates surface water temperature signals, and this attenuation can be diagnostic of groundwater gaining systems. Additionally, discharge from shallow groundwater flowpaths can theoretically transfer lagged annual temperature signals from aquifer to stream water. Here we explore this concept using multi-year temperature records from 120 stream sites located across 18 mountain watersheds of Shenandoah National Park, VA, USA and a coastal watershed in Massachusetts, USA. Both areas constitute important cold-water habitat for native brook trout ( Salvelinus fontinalis ). Observed annual temperature signals indicate a dominance of shallow groundwater discharge to streams in the National Park, in contrast to the coastal watershed that has strong, apparently deeper, groundwater influence. The average phase lag from air to stream signals in Shenandoah National Park is 11 d; however, extended lags of approximately 1 month were observed in a subset of streams. In contrast, the coastal stream has pronounced attenuation of annual temperature signals without notable phase lag. To better understand these observed differences in signal characteristics, analytical and numerical models are used to quantify mixing of the annual temperature signals of surface and groundwater. Simulations using a total heat budget numerical model indicate groundwater-induced annual temperature signal phase lags are likely to show greater downstream propagation than the related signal amplitude attenuation. The measurement of multi-seasonal paired air and water temperatures offers great promise toward understanding catchment processes and informing current cold-water habitat management at ecologically-relevant scales.

Virginia↗
USGS2018

Chesapeake Bay's water quality condition has been recovering: Insights from a multimetric indicator assessment of thirty years of tidal monitoring data

To protect the aquatic living resources of Chesapeake Bay, the Chesapeake Bay Program partnership has developed guidance for state water quality standards, which include ambient water quality criteria to protect designated uses (DUs), and associated assessment procedures for dissolved oxygen (DO), water clarity/underwater bay grasses, and chlorophyll-a. For measuring progress toward meeting the respective states' water quality standards, a multimetric attainment indicator approach was developed to estimate combined standards attainment. We applied this approach to three decades of monitoring data of DO, water clarity/underwater bay grasses, and chlorophyll-a data on annually updated moving 3-year periods to track the progress in all 92 management segments of tidal waters in Chesapeake Bay. In 2014–2016, 40% of tidal water segment-DU-criterion combinations in the Bay (n = 291) are estimated to meet thresholds for attainment of their water quality criteria. This index score marks the best 3-year status in the entire record. Since 1985–1987, the indicator has followed a nonlinear trajectory, consistent with impacts from extreme weather events and subsequent recoveries. Over the period of record (1985–2016), the indicator exhibited a positive and statistically significant trend ( p < 0.05), indicating that the Bay has been recovering since 1985. Patterns of attainment of individual DUs are variable, but improvements in open water DO, deep channel DO, and water clarity/submerged aquatic vegetation have combined to drive the improvement in the Baywide indicator in 2014–2016 relative to its long-term median. Finally, the improvement in estimated Baywide attainment was statistically linked to the decline of total nitrogen, indicating responsiveness of attainment status to the reduction of nutrient load through various management actions since at least the 1980s.

Chesapeake Bay watershed↗
USGS2018

Examination of contaminant exposure and reproduction of ospreys (Pandion haliaetus) nesting in Delaware Bay and River in 2015

A study of ospreys ( Pandion haliaetus ) nesting in the coastal Inland Bays of Delaware, and the Delaware Bay and Delaware River in 2015 examined spatial and temporal trends in contaminant exposure, food web transfer and reproduction. Concentrations of organochlorine pesticides and metabolites, polychlorinated biphenyls (PCBs), coplanar PCB toxic equivalents, polybrominated diphenyl ethers (PBDEs) and other flame retardants in sample eggs were generally greatest in the Delaware River. Concentrations of legacy contaminants in 2015 Delaware Bay eggs were lower than values observed in the 1970s through early 2000s. Several alternative brominated flame retardants were rarely detected, with only TBPH [bis(2-ethylhexyl)-tetrabromophthalate)] present in 5 of 27 samples at <5 ng/g wet weight. No relation was found between p,p ′-DDE, total PCBs or total PBDEs in eggs with egg hatching, eggs lost from nests, nestling loss, fledging and nest success. Osprey eggshell thickness recovered to pre-DDT era values, and productivity was adequate to sustain a stable population. Prey fish contaminant concentrations were generally less than those in osprey eggs, with detection frequencies and concentrations greatest in white perch ( Morone americana ) from Delaware River compared to the Bay. Biomagnification factors from fish to eggs for p,p ′-DDE and total PCBs were generally similar to findings from several Chesapeake Bay tributaries. Overall, findings suggest that there have been improvements in Delaware Estuary waterbird habitat compared to the second half of the 20th century. This trend is in part associated with mitigation of some anthropogenic contaminant threats.

Delaware Bay and River↗
USGS2018

Quantifying anthropogenic contributions to century-scale groundwater salinity changes, San Joaquin Valley, California, USA

Total dissolved solids (TDS) concentrations in groundwater tapped for beneficial uses (drinking water, irrigation, freshwater industrial) have increased on average by about 100 mg/L over the last 100 years in the San Joaquin Valley, California (SJV). During this period land use in the SJV changed from natural vegetation and dryland agriculture to dominantly irrigated agriculture with growing urban areas. Century-scale salinity trends were evaluated by comparing TDS concentrations and major ion compositions of groundwater from wells sampled in 1910 (Historic) to data from wells sampled in 1993-2015 (Modern). TDS concentrations in subregions of the SJV, the southern (SSJV), western (WSJV), northeastern (NESJV), and southeastern (SESJV) were calculated using a cell-declustering method. TDS concentrations increased in all regions, with the greatest increases found in the SSJV and SESJV. Evaluation of the Modern data from the NESJV and SESJV found higher TDS concentrations in recently recharged (post-1950) groundwater from shallow (< 50 m) wells surrounded predominantly by agricultural land uses, while premodern (pre-1950) groundwater from deeper wells, and recently recharged groundwater from wells surrounded by mainly urban, natural, and mixed land uses had lower TDS concentrations, approaching the TDS concentrations in the Historic groundwater. For the NESJV and SESJV, inverse geochemical modeling with PHREEQC indicated that weathering of primary silicate minerals accounted for the majority of the increase in TDS concentrations, contributing more than nitrate from fertilizers and sulfate from soil amendments combined. Bicarbonate showed the greatest increase among major ions, resulting from enhanced silicate weathering due to recharge of irrigation water enriched in CO2 during the growing season. The results of this study demonstrate that large anthropogenic changes to the hydrologic regime, like massive development of irrigated agriculture in semi-arid areas like the SJV, can cause large changes in groundwater quality on a regional scale.

California↗
USGS2020

Relation of fish intersex to contaminants in riverine sport fishes

Endocrine active compounds (EACs) are pollutants that have been recognized as an emerging and widespread threat to aquatic ecosystems globally. Intersex, the presence of female germ cells within a predominantly male gonad, is considered a biomarker of endocrine disruption caused by EACs. We measured a suite of EACs and assessed their associated impacts on fish intersex occurrence and severity in a large, regulated river system in North Carolina and South Carolina, USA. Our specific objective was to determine the relationship of contaminants in water, sediment, and fish tissue with the occurrence and severity of the intersex condition in wild, adult black bass ( Micropterus ), sunfish ( Lepomis ), and catfish (Ictaluridae) species at 11 sites located on the Yadkin-Pee Dee River. Polycyclic aromatic hydrocarbons (PAHs), ethinylestradiol (EE2), and heavy metals were the most prevalent contaminants that exceeded effect levels for the protection of aquatic organisms. Fish intersex condition was most frequently observed and most severe in black basses and was less frequently detected and less severe in sunfishes and catfishes. The occurrence of the intersex condition in fish showed site-related effects, rather than increasing longitudinal trends from upstream to downstream. Mean black bass and catfish tissue contaminant concentrations were higher than that of sunfish, likely because of the latter's lower trophic position in the food web. Principal component analysis identified waterborne PAHs as the most correlated environmental contaminant with intersex occurrence and severity in black bass and sunfish. As indicated by the intersex condition, EACs have adverse but often variable effects on the health of wild sport fishes in this river, likely due to fluctuations in EAC inputs and the dynamic nature of the riverine system. These findings enhance the understanding of the relationship between contaminants and fish health and provide information to guide ecologically comprehensive conservation and management decisions.

North Carolina, South Carolina↗
USGS2018

Pharmaceuticals, hormones, pesticides, and other bioactive contaminants in water, sediment, and tissue from Rocky Mountain National Park, 2012–2013

Pharmaceuticals, hormones, pesticides, and other bioactive contaminants (BCs) are commonly detected in surface water and bed sediment in urban and suburban areas, but these contaminants are understudied in remote locations. In Rocky Mountain National Park (RMNP), Colorado, USA, BCs may threaten the reproductive success and survival of native aquatic species, benthic communities, and pelagic food webs. In 2012–2013, 67 water, 57 sediment, 63 fish, 10 frog, and 12 quality-control samples (8 water and 4 sediment) were collected from 20 sites in RMNP. Samples were analyzed for 369 parameters including 149 pharmaceuticals, 22 hormones, 137 pesticides, and 61 other chemicals or conditions to provide a representative assessment of BC occurrence within RMNP. Results indicate that BCs were detected in water and/or sediment from both remote and more accessible locations in RMNP. The most commonly detected BCs in water were caffeine, camphor, para-cresol, and DEET; and the most commonly detected BCs in sediment were indole, 3-methyl-1H-indole, para-cresol, and 2,6-dimethyl-naphthalene. Some detected contaminants, including carbaryl, caffeine, and oxycodone, are clearly attributable to direct local human input, whereas others may be transported into the park atmospherically (e.g., atrazine) or have local natural sources (e.g., para-cresol). One or more pharmaceuticals were detected in at least 1 sample from 15 of 20 sites. Most of the 29 detected pharmaceuticals are excreted primarily in human urine, not feces. Elevated net estrogenicity was observed in 18% of water samples, and elevated vitellogenin in blood was observed in 12% of male trout, both evidence of potential endocrine disruption. Hormone concentrations in sediment tended to be greater than concentrations in water. Most BCs were observed at concentrations below those not expected to pose adverse effects to aquatic life. Results indicate that even in remote locations aquatic wildlife can be exposed to pharmaceuticals, hormones, pesticides, and other bioactive contaminants.

Colorado↗
USGS2018

Temporal evaluation of estrogenic endocrine disruption markers in smallmouth bass (Micropterus dolomieu) reveals seasonal variability in intersex

A reconnaissance project completed in 2009 identified intersex and elevated plasma vitellogenin in male smallmouth bass inhabiting the Missisquoi River, VT. In an attempt to identify the presence and seasonality of putative endocrine disrupting chemicals or other factors associated with these observations, a comprehensive reevaluation was conducted between September 2012 and June 2014. Here, we collected smallmouth bass from three physically partitioned reaches along the river to measure biomarkers of estrogenic endocrine disruption in smallmouth bass. In addition, polar organic chemical integrative samples (POCIS) were deployed to identify specific chemicals associated with biological observations. We did not observe biological differences across reaches indicating the absence of clear point source contributions to the observation of intersex. Interestingly, intersex prevalence and severity decreased in a stepwise manner over the timespan of the project. Intersex decreased from 92.8% to 28.1%. The only significant predictor of intersex prevalence was year of capture, based on logistic regression analysis. The mixed model of fish length and year-of-capture best predicted intersex severity. Intersex severity was also significantly different across late summer and early spring collections indicating seasonal changes in this metric. Plasma vitellogenin and liver vitellogenin Aa transcript abundance in males did not indicate exposure to estrogenic endocrine disrupting chemicals at any of the four sample collections. Analysis of chemicals captured by the POCIS as well as results of screening discrete water samples or POCIS extracts did not indicate the contribution of appreciable estrogenic chemicals. It is possible that unreported changes in land-use activity have ameliorated the problem, and our observations indicate recovery. Regardless, this work clearly emphasizes that single, snap shot sampling for intersex may not yield representative data given that the manifestation of this condition within a population can change dramatically over time.

Vermont↗
USGS2019

Effects of ferric sulfate and polyaluminum chloride coagulation enhanced treatment wetlands on Typha growth, soil and water chemistry

Land surface subsidence is a concern in many deltas worldwide as it contributes to water quality degradation, loss of fertile land and increased potential for levee failure. As a possible solution to these concerns, on-site coagulation enhanced treatment wetlands(CETWs), coagulation water treatment followed by wetland passage serving as a settling basin, were implemented in a field-scale study located on a subsided island of the Sacramento-San Joaquin Delta in northern California under three treatments; coagulation with polyaluminum chloride (PAC), coagulation with ferric sulfate and an untreated control. Because CETWs offer a relatively novel solution for water quality improvement and subsidence reversal due to its low-infrastructure requirements and in-situ nature, effects from these systems remain uncharted and they may have adverse effects on plant biomass production that also contribute to sediment accretion. This study focuses on the effect CETWs had on the growth of Typha spp .; the dominant vegetation in the wetlands. Plant growth parameters and nutrient content were measured in conjunction with soil, pore waterand surface water chemistry. Soil analysis indicated there was no intermixing of newly formed flocs and original soil material. Where there was significant deposition of floc, PAC treatment reduced phosphate concentrations and ferric sulfate treatment increased total Fe concentrations in surrounding water compared to the control. Results indicated coagulation treatments had no negative effects on Typha leaf nutrient content, Typha growth or allometric parameters. Additionally, no signs of plant toxicity such as necrosis, wilting or chlorosis were observed in any of the treatments. Overall, this study suggests that CETWs are viable treatment option for water quality improvement and sediment accretion while having no negative impact on the growth of Typha plants.

Science of the Total Environment↗