bluuebunny/crossref_metadata_2025 huggingface dataset:
THE LIFE AND WORK OF JOHN BRADBY BLAKE
Authors: Goodman Jordan , Crane Peter
Published: March 2018

John Bradby Blake (1745–1773) first visited Canton as a supercargo for the British East India Company in 1767/68. He returned as a resident supercargo in July 1769. Between then and his untimely death in 1773, in collaboration with one or more Chinese artists, he produced over 150 paintings of Chinese plants, many of which are illustrated in exquisite botanical detail. These paintings and the associated archives in the Oak Spring Garden Library at the Oak Spring Garden Foundation (OSGF) provide a detailed glimpse into an interesting life and a previously little known dimension of the social and scientific interactions between the British and Chinese in the late 18th century.
CHINESE VISITORS TO 18TH CENTURY BRITAIN AND THEIR CONTRIBUTION TO ITS CULTURAL AND INTELLECTUAL LIFE
Authors: Clarke David
Published: March 2018

This essay introduces three 18th century Chinese visitors to Britain, analysing the important role they played in cross‐cultural intellectual and artistic contact between the two countries. Loum Kiqua, a merchant, arrived in London in 1756. He gave the first known performance on a Chinese musical instrument in the West. Chitqua, a portrait modeller who arrived in 1769, exhibited at the newly‐established Royal Academy (becoming the first named Chinese artist to have a work shown in an overseas exhibit). Whang at Tong (Whang Atong, Huang Yadong), was only in his early 20s at the time of his arrival in England in August 1774, but he played a significant role in the transfer of botanical knowledge from China to the West through his connections with John Bradby Blake in Canton and his father John Blake in London.
FOLLOWING THE THREAD TO OAK SPRING: THE AFTERLIFE OF JOHN BRADBY BLAKE'S CANTON DRAWINGS
Authors: Goodman Jordan
Published: March 2018

For more than 175 years, the remarkable botanical drawings made in Canton by a Chinese artist working with the British East India Company supercargo John Bradby Blake, were handed down from generation to generation within the same family. They first appeared publicly in 1959 when the estate of Sir Frederick Cripps of Ampney Park, Gloucestershire, came up for auction. A Bristol art dealer bought the drawings, but on the other side of the Atlantic, Paul Mellon had other ideas for them. This article follows the trail from London, via Ampney Park and Bristol, to Oak Spring, Virginia.
JOHN BRADBY BLAKE'S MULTIMEDIA DICTIONARY: FROM WORDLIST TO WORLDVIEW
Authors: St. André James
Published: March 2018

The unique illustrated and annotated ‘Chinese‐English Vocabulary’ (hereafter ‘Vocabulary’) in the John Bradby Blake collection in the library of the Oak Spring Garden Foundation is described, along with the composition of individual entries and their arrangement. Analysis of the contents suggests that the Vocabulary was composed in a multi‐layered process beginning with the illustration and main Chinese characters, which were then annotated by two other individuals, most likely John Bradby Blake himself and perhaps Whang at Tong. The layers of the Vocabulary document an attempt at cross‐cultural exchange, with equivalences being proposed, explanations offered, and meanings contested. Situating the Vocabulary in the history of Chinese language learning and the more general history of bilingual wordlists reveals various types of precedents and related material, but it is unique in the history of Chinese‐English lexicography and what it has to teach us about the worldview of its authors and mid‐Qing intellectual knowledge exchange between British and Southern Chinese.
THE BRITISH EAST INDIA COMPANY, JOHN BRADBY BLAKE AND THEIR INTERESTS IN SPICES, COTTON AND TEA
Authors: Pickersgill Barbara
Published: March 2018

The British East India Company was founded to compete with the Dutch in the lucrative trade in spices, but the Company soon abandoned this attempt and concentrated instead on trading cotton goods from the Indian subcontinent, initially to Britain, but subsequently to China in part‐exchange for tea. Dutch control of spice prices and the drain on Company finances of paying the Chinese for ever‐increasing quantities of tea led to attempts to introduce some of the species concerned to British colonies with appropriate climates. As the Company's resident supercargo in Canton, John Bradby Blake collected and sent back to Britain various species for introduction to the Americas, and drew and painted these and many others. Few of these attempted introductions succeeded, but the surviving paintings constitute his lasting legacy.
JOHN BRADBY BLAKE, THE CHINESE TALLOW TREE AND THE INFRASTRUCTURE OF BOTANICAL EXPERIMENTATION
Authors: Batchelor Robert
Published: March 2018

Recent studies of the spread of the invasive Chinese tallow tree, , Triadica sebifera (L.) Small, downplay the role of the dissemination of seeds in the 18th century compared with the impact of 20th century state‐sponsored agriculture. But the long‐term development of Chinese, then European and American botanical knowledge, even in cases like the tallow tree, can be shown to have enabled and legitimized ecological expansion and large scale environmental experimentation. John Bradby Blake, who obtained, experimented with, described and illustrated tallow tree seed in the 1770s, played an important role in the dissemination of tallow trees to the southeastern American colonies, the British Caribbean and northeast India.
‘THOROUGHLY CHINESE’: REVEALING THE PLANTS OF THE HONG MERCHANTS' GARDENS THROUGH JOHN BRADBY BLAKE'S PAINTINGS
Authors: Richard Josepha , Woudstra Jan
Published: March 2018

The paintings in the John Bradby Blake collection should be admired for their sophisticated artistry and accurate depiction of botanical features, but they are also significant because they reveal the diversity of plants grown in the gardens of Chinese in Guangzhou (Canton). They therefore provide a precious insight into a relatively neglected topic in Chinese garden history, namely the cultivation of plants in gardens. This paper identifies one of the gardens from which the plants depicted by John Bradby Blake might have come, and looks at how those plants were used and appreciated in their Chinese context.
INTRODUCTION
Authors: Crane Peter , Loehle Zack
Published: March 2018

The Oak Spring Garden Library, a legacy of Rachel Lambert Mellon (1910–2014) and now part of the Oak Spring Garden Foundation, contains the archive of John Bradby Blake (1745–1773), a young trader who worked for the British East India Company in the late 1760s and early 1770s in Canton (Guangzhou) and Macau. The archive provides an unusually detailed insight into Bradby Blake's life and botanical work, including his attempts to send living plants back to England. The archive also contains almost 200 pieces of exquisitely detailed early British‐Chinese hybrid botanical art, which Bradby Blake prepared with a Chinese artist, Mauk‐Sow‐U. With their emphasis on botanical detail and careful depiction of the detailed structure of flowers, these illustrations are as accurate as any produced at this relatively early date in the post‐Linnaean development of botanical science.
Smoking behaviour and preferences for cessation support among clients of an Indigenous community‐controlled health service
Authors: Cockburn Nicole , Gartner Coral , Ford Pauline J.
Published: March 2018

Introduction and Aims

Reducing smoking prevalence among Indigenous Australians is a vital part of closing the health gap between Indigenous and non‐Indigenous Australians. Community‐controlled health clinics are an important setting for delivering smoking cessation advice and assistance. This study measured tobacco and e‐cigarette use, knowledge of smoking‐related health effects, motivations to quit and interest in cessation aids.

Design and Methods

Clients of Aboriginal & Torres Strait Islander Community Health Service dental clinics in Southeast Queensland (n = 421) completed a brief written questionnaire while in the waiting room.

Results

Nearly half (n = 184, 47%) of the participants currently smoked daily, of which 9% (n = 7) currently used e‐cigarettes. Few smokers (8%, n = 13) had no intention to quit smoking. For current smokers, previously used quit methods were abrupt cessation (42%, n = 78), nicotine replacement therapies (NRT; 25%, n = 45), prescription medications (23%, n = 43), e‐cigarettes (9%, n = 17) and other methods (3%, n = 6). Current smokers were most interested in cutting down (85%, n = 110), abrupt cessation (75%, n = 98) and free NRT (72%, n = 101). Fewer (34%, n = 36) were interested in purchasing NRT for smoking cessation.

Discussion and Conclusions

Our study found there was interest in accessing smoking cessation aids among the clients of this community‐controlled health clinic, particularly if provided free of charge. Embedding smoking cessation advice and assistance into a range of community‐controlled health clinics could provide opportunities for addressing the high smoking prevalence among Indigenous Australians.
Ultra‐early occlusion of the normal bile duct after uncovered self‐expandable metallic stent placement in unresectable perihilar bile duct cancer
Authors: Kawakami Hiroshi , Kubota Yoshimasa , Ban Tesshin
Published: March 2018

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Overt gastrointestinal bleeding caused by hookworm infection, diagnosed by capsule endoscopy
Authors: Blanco‐Velasco Gerardo , Solorzano‐Pineda Omar , Hernández‐Mondragón Oscar Víctor
Published: March 2018

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Body size and fecundity are correlated in feather lice (Phthiraptera: Ischnocera): implications for Harrison's rule
Authors: VILLA SCOTT M. , EVANS MCKENNA D. , SUBHANI YUMNA K. , ALTUNA JUAN C. , BUSH SARAH E. , CLAYTON DALE H.
Published: March 2018

1. Harrison's rule, which predicts that large‐bodied species of hosts have large‐bodied species of parasites, has been documented in a wide diversity of parasites.

2. Harrison's rule has been most thoroughly studied in avian feather lice, which escape from host defence (preening) by hiding in the feathers. Lice that are unable to hide are selectively removed by preening. Preening selects for small lice on small hosts, which have small feathers in which to hide.

3. Preening should not, however, select for large lice on large hosts. Instead, the larger size of lice on large hosts is thought to result from a positive relationship between size and fecundity, as shown for many other insects.

4. This study tested for a size–fecundity correlation within Columbicola columbae, the host‐specific ‘wing louse’ of rock pigeons (Columba livia).

5. The results confirm a positive relationship between female body length and number of eggs laid.

6. The study thus supports a mechanism consistent with stabilising selection leading to the evolution of the Harrison's rule pattern among species of Columbicola and their hosts.
Self‐assessment of ergonomics amongst dental students utilising photography: RCT
Authors: Partido B. B. , Wright B. M.
Published: March 2018

Introduction

Dental professionals are at high risk of musculoskeletal disorders (MSDs) due to static working positions for extended periods of time. Musculoskeletal pain has been identified as early as during their entry‐level dental education. The purpose of this study was to determine whether feedback involving photography and self‐assessment would improve ergonomic scores and the accuracy of ergonomic self‐assessments amongst dental students.

Materials and Methods

The study involved a randomised control design of 135 dental students. At weeks 1 and 4, participants were photographed, and at weeks 1 through 4, participants completed ergonomic self‐evaluations, using a Modified‐Dental Operator Posture Assessment Instrument (M‐DOPAI). During weeks 2 and 3, participants in the training group were photographed and used those photographs to complete ergonomic self‐assessments. All participants’ pre‐training and post‐training photographs were evaluated for ergonomic scores by two raters.

Results

A mixed‐design ANOVA of ergonomic scores revealed that ergonomic scores improved for all students who received the ergonomics training (F(1,254)=17.41, P < .001). In addition, a mixed‐design ANOVA of kappa coefficient values between student and rater scores revealed that the accuracy of self‐assessments improved for all students who received the ergonomics training (F(1,127)=6.33, P < .05).

Conclusion

The use of photographs and self‐assessment provides dental and dental hygiene educators with a pragmatic method to improve self‐assessment skills, increase student awareness of any postural deviations from ideal and improve musculoskeletal health.
What can we learn from using formal patient‐reported outcome instruments to assess pain, functional impairment, anxiety, and depression in US adults with hemophilia?
Authors: Buckner Tyler W. , Batt Katharine , Cooper David L. , Kempton Christine L.
Published: March 2018

People with hemophilia frequently suffer from arthropathy that leads to pain and functional impairment, ultimately resulting in reduced quality of life. The impact of pain and functional impairment on the lives of people with hemophilia was explored in the Pain, Functional Impairment, and Quality of Life (P‐FiQ) study. Various patient‐reported outcome (PRO) instruments were employed to assess the effect of pain and functional impairment on multiple aspects of health in people with hemophilia. The results presented in this supplement include detailed observations from PRO instruments regarding pain, functional impairment, anxiety, and depression, an analysis of the differences in health‐related quality of life across subgroups of patients defined by demographic and treatment‐related characteristics, and results of a modeling analysis to identify patient factors which influence perceptions of pain and functional impairment, independent of joint status. These data provide insights into how the results from PRO assessments may be used to evaluate outcomes for people with hemophilia in the clinical and research settings.
Processing of performance‐matched visual object categories: faces and places are related to lower processing load in the frontoparietal executive network than other objects
Authors: Jorge Lília , Canário Nádia , Castelhano João , Castelo‐Branco Miguel
Published: March 2018

This study aimed to explore the differential role of the frontoparietal network in processing different visual object categories, matched for difficulty level, during a 1‐back paradigm. To achieve this goal, we first mapped the effort‐related frontoparietal saliency network, by contrasting activation elicited by face, object, place, body and verbal stimulus categories, which were matched for performance level, and speed of processing, with difficult scrambled stimuli. We then computed the weight of object predictors on that specific network, using an independent orthogonal analysis. Overall, our results demonstrated that face (and to some extent also places) stimuli were associated with lower processing load in regions of the frontoparietal network comparing to other visual categories, suggesting that face/place processing does require to a much smaller extent the recruitment of the frontoparietal control network than any other object categories. Thus, face detection and place detection seem to be routed in specific neuronal systems that readily encode the holistic nature of this type of objects. We conclude that the more limited recruitment of frontoparietal networks reflects the automaticity of face and place processing and their smaller dependence on general capacity limits.
Ryanodine receptor type 3 (RYR3) as a novel gene associated with a myopathy with nemaline bodies
Authors: Nilipour Y. , Nafissi S. , Tjust A. E. , Ravenscroft G. , Hossein Nejad Nedai H. , Taylor R. L. , Varasteh V. , Pedrosa Domellöf F. , Zangi M. , Tonekaboni S. H. , Olivé M. , Kiiski K. , Sagath L. , Davis M. R. , Laing N. G. , Tajsharghi H.
Published: March 2018

Background and purpose

Nemaline myopathy (NEM) has been associated with mutations in 12 genes to date. However, for some patients diagnosed with NEM, definitive mutations are not identified in the known genes, suggesting that there are other genes involved. This study describes compound heterozygosity for rare variants in ryanodine receptor type 3 (RYR3) gene in one such patient.

Methods and results

Clinical examination of the patient at 22 years of age revealed a long narrow face, high arched palate and bilateral facial weakness. She had proximal weakness in all four limbs, mild scapular winging but no scoliosis. Muscle biopsy revealed wide variation in fibre size with type 1 fibre predominance and atrophy. Abundant nemaline bodies were located in perinuclear and subsarcolemmal areas, and within the cytoplasm. No likely pathogenic mutations in known NEM genes were identified. Copy number variation in known NEM genes was excluded by NEM‐targeted comparative genomic hybridization array. Next‐generation sequencing revealed compound heterozygous missense variants in the RYR3 gene. RYR3 transcripts are expressed in human fetal and adult skeletal muscle as well as in human brain and cauda equina samples. Immunofluorescence of human skeletal muscle revealed a ‘single‐row’ appearance of RYR3, interspersed between the ‘double rows’ of ryanodine receptor type 1 (RYR1) at each A–I junction.

Conclusion

The results suggest that variants in RYR3 may cause a recessive muscle disease with pathological features including nemaline bodies. We characterize the expression pattern of RYR3 in human skeletal muscle and brain, and the subcellular localization of RYR1 and RYR3 in human skeletal muscle.
IL‐26 in allergic contact dermatitis: Resource in a state of readiness
Authors: Caiazzo Giuseppina , Di Caprio Roberta , Lembo Serena , Raimondo Annunziata , Scala Emanuele , Patruno Cataldo , Balato Anna
Published: March 2018

In this study, we investigated the role of IL‐26 in allergic contact dermatitis (ACD), highlighting its’ contribute in the cytotoxic mechanism responsible for the tissue injury. IL‐26 is a signature Th17 cytokine, and immune cells are its predominant sources. Recently, it has shown that Th17 cell‐derived‐IL‐26 functions like an antimicrobial peptide. Here, we hypothesized that IL‐26 could be involved in cytotoxicity mechanism that underlies ACD. Indeed, we have attributed a role to IL‐26 in this context, through PBMC cytotoxicity assays vs HaCat. To demonstrate that IL‐26 was effectively involved in this activity, we performed the assay using transfected ACD PBMCs by siRNA for IL‐26. Indeed, we demonstrated that these cells were less able to kill keratinocytes compared with ACD PBMCs (P < .01). In conclusion, our findings support the idea that this emergent cytokine, IL‐26, is implicated in the killing mechanisms of KC observed during ACD.
Bioturbation and directionality in Earth's carbon isotope record across the Neoproterozoic–Cambrian transition
Authors: Boyle R. A. , Dahl T. W. , Bjerrum C. J. , Canfield D. E.
Published: March 2018

Mixing of sediments by moving animals becomes apparent in the trace fossil record from about 550 million years ago (Ma), loosely overlapping with the tail end of the extreme carbonate carbon isotope δ13Ccarbonate fluctuations that qualitatively distinguish the Proterozoic geochemical record from that of the Phanerozoic. These Precambrian‐scale fluctuations in δ13Ccarbonate (PSF‐δ13Ccarbonate) remain enigmatic, due to their high amplitude and inclusion of global‐scale negative δ13Ccarbonate values, below anything attributable to mantle input. Here, we note that different biogeochemical‐model scenarios plausibly explaining globally synchronous PSF‐δ13Ccarbonate converge: via mechanistic requirements for extensive anoxia in marine sediments to support sedimentary build‐up of 13C‐depleted carbon. We hypothesize that bioturbation qualitatively reduced marine sediment anoxia by exposing sediments to oxygenated overlying waters, which ultimately contributed to decreasing the carbon cycle's subsequent susceptibility to PSF‐ δ13Ccarbonate. Bioturbation may also have reduced the quantity of (isotopically light) organic‐derived carbon available to contribute to PSF‐ δ13Ccarbonate via ocean crust carbonatization at depth. We conduct a comparative modelling exercise in which we introduce bioturbation to existing model scenarios for PSF‐ δ13Ccarbonate: expressing both the anoxic proportion of marine sediments, and the global organic carbon burial efficiency, as a decreasing function of bioturbation. We find that bioturbation's oxygenating impact on sediments has the capacity to prevent PSF‐ δ13Ccarbonate caused by authigenic carbonate precipitation or methanogenesis. Bioturbation's impact on the f‐ratio via remineralization is partially offset by liberation of organic phosphate, some of which feeds back into new production. We emphasize that this study is semiquantitative, exploratory and intended merely to provide a qualitative theoretical framework within which bioturbation's impact on long‐term, first‐order δ13Ccarbonate can be assessed (and it is hoped quantified in more detail by future work). With this proviso, we conclude that it is entirely plausible that bioturbation made a decisive contribution to the enigmatic directionality in the δ13Ccarbonate record, from the Neoproterozoic–Cambrian boundary onwards.
Orthostatic hypotension and overall mortality in 1050 older patients of the outpatient comprehensive geriatric assessment unit
Authors: Freud Tamar , Punchik Boris , Kagan Ella , Barzak Alex , Press Yan
Published: March 2018

Aim

Orthostatic hypotension is a common problem in individuals aged ≥65 years. Its association with mortality is not clear. The aim of the present study was to evaluate associations between orthostatic hypotension and overall mortality in a sample of individuals aged ≥65 years who were seen at the Outpatient Comprehensive Geriatric Assessment Unit, Clalit Health Services, Beer‐Sheva, Israel.

Methods

Individuals who were evaluated in the Outpatient Comprehensive Geriatric Assessment Unit between January 2005 and December 2015, and who had data on orthostatic hypotension were included in the study. The database included sociodemographic characteristics, body mass index, functional and cognitive state, geriatric syndromes reached over the course of the assessment, and comorbidity. Data on mortality were also collected.

Results

The study sample included 1050 people, of whom 626 underwent comprehensive geriatric assessment and 424 underwent geriatric consultation. The mean age was 77.3 ± 5.4 years and 35.7% were men. Orthostatic hypotension was diagnosed in 294 patients (28.0%). In univariate analysis, orthostatic hypotension was associated with overall mortality only in patients aged 65–75 years (HR 1.5, 95% CI 1.07–2.2), but in the multivariate model this association disappeared.

Conclusions

In older frail patients, orthostatic hypotension was not an independent risk factor for overall mortality. Geriatr Gerontol Int 2018; 18: 1009–1017.
Is anemia associated with cognitive impairment and delirium among older acute surgical patients?
Authors: Myint Phyo Kyaw , Owen Stephanie , McCarthy Kathryn , Pearce Lyndsay , Moug Susan J , Stechman Michael J , Hewitt Jonathan , Carter Ben
Published: March 2018

Aim

The determinants of cognitive impairment and delirium during acute illness are poorly understood, despite being common among older people. Anemia is common in older people, and there is ongoing debate regarding the association between anemia, cognitive impairment and delirium, primarily in non‐surgical patients.

Methods

Using data from the Older Persons Surgical Outcomes Collaboration 2013 and 2014 audit cycles, we examined the association between anemia and cognitive outcomes in patients aged ≥65 years admitted to five UK acute surgical units. On admission, the Confusion Assessment Method was carried out to detect delirium. Cognition was assessed using the Montreal Cognitive Assessment, and two levels of impairment were defined as Montreal Cognitive Assessment <26 and <20. Logistic regression models were constructed to examine these associations in all participants, and individuals aged ≥75 years only.

Results

A total of 653 patients, with a median age of 76.5 years (interquartile range 73.0–80.0 years) and 53% women, were included. Statistically significant associations were found between anemia and age; polypharmacy; hyperglycemia; and hypoalbuminemia. There was no association between anemia and cognitive impairment or delirium. The adjusted odds ratios of cognitive impairment were 0.95 (95% CI 0.56–1.61) and 1.00 (95% CI 0.61–1.64) for the Montreal Cognitive Assessment <26 and <20, respectively. The adjusted odds ratio of delirium was 1.00 (95% CI 0.48–2.10) in patients with anemia compared with those without. Similar results were observed for the ≥75 years age group.

Conclusions

There was no association between anemia and cognitive outcomes among older people in this acute surgical setting. Considering the retrospective nature of the study and possible lack of power, findings should be taken with caution. Geriatr Gerontol Int 2018; 18: 1025–1030.
Comparison of Continuous Core Profiles and Monitoring Wells for Assessing Groundwater Contamination by Agricultural Nitrate
Authors: Bourke Sarah A. , Turchenek Jonathan , Schmeling Erin E. , Mahmood F. Nessa , Olson Barry M. , Hendry M. Jim
Published: March 2018

Studies that assess groundwater contamination by agricultural nitrate (NO3−) commonly measure groundwater chemistry in samples collected from monitoring wells. This approach can be limited by coarse vertical resolution and aquifer heterogeneity. In this paper, we compare continuous core profiles against samples from monitoring wells for assessing agricultural nitrate contamination. Stable isotopes (δ2H and δ18O), chloride (Cl−), and NO3− were measured in four nested wells and continuous core collected to depths of up to 20 m on three different sampling dates at a site in Alberta, Canada. Continuous core profiles of stable isotopes are used to define solute transport zones (advection‐dispersion dominated vs. diffusion dominated), which then informs the interpretation of the Cl− and NO3− profiles. Data from monitoring wells were particularly useful for capturing the temporal dynamics near the water table, but could not be used to define the dominant transport zones. Given the temporal variation in mass input of agricultural NO3−, the increased spatial resolution of continuous core profiles provides an advantage over samples from monitoring wells to assess groundwater contamination by agricultural NO3−. The relatively fine spatial resolution of continuous core profiles is particularly useful for assessing rates of NO3− attenuation through denitrification. This benefit is offset by the need to resample the entire profile at each sampling time, in contrast to groundwater wells, which can be sampled repeatedly with time. Vertical profiling of continuous core is recommended in addition to monitoring wells to assess near‐surface groundwater contamination, particularly at sites where vertical heterogeneity in hydraulic conductivity on the scale of metres or less is likely.
Electrokinetic Migration of Nitrate Through Heterogeneous Granular Porous Media
Authors: Gill Richard T. , Thornton Steven F. , Harbottle Michael J. , Smith Jonathan W.N.
Published: March 2018

This study investigates and quantifies the influence of physical heterogeneity in granular porous media, represented by materials with different hydraulic conductivity, on the migration of nitrate, used as an amendment to enhance bioremediation, under an electric field. Laboratory experiments were conducted in a bench‐scale test cell under a low applied direct current using glass bead and clay mixes and synthetic groundwater to represent ideal conditions. The experiments included bromide tracer tests in homogeneous settings to deduce controls on electrokinetic transport of inorganic solutes in the different materials, and comparison of nitrate migration under homogeneous and heterogeneous scenarios. The results indicate that physical heterogeneity of subsurface materials, represented by a contrast between a higher‐hydraulic conductivity and lower‐hydraulic conductivity material normal to the direction of the applied electric field exerts the following controls on nitrate migration: (1) a spatial change in nitrate migration rate due to changes in effective ionic mobility and subsequent accumulation of nitrate at the interface between these materials; and (2) a spatial change in the voltage gradient distribution across the hydraulic conductivity contrast, due to the inverse relationship with effective ionic mobility. These factors will contribute to higher mass transport of nitrate through low hydraulic conductivity zones in heterogeneous porous media, relative to homogeneous host materials. Overall electrokinetic migration of amendments such as nitrate can be increased in heterogeneous granular porous media to enhance the in situ bioremediation of organic contaminants present in low hydraulic conductivity zones.
Monitoring In Situ Biodegradation of MTBE Using Multiple Rounds of Compound‐Specific Stable Carbon Isotope Analysis
Authors: Lu Jun , Muramoto Frank , Philp Paul , Kuder Tomasz
Published: March 2018

At a large industrial facility, methyl tert‐butyl ether (MTBE) was released to the subsurface and dispersed into the light, non‐aqueous phase liquids (LNAPL), in the first aquifer, with the LNAPL serving as a continuous source of MTBE in groundwater. Compound‐specific isotope analysis was conducted on both MTBE and tert‐butyl alcohol (TBA) in groundwater samples collected in 2008, 2011, and 2013 from wells located along and off the center line of the MTBE plume. The study demonstrated the onset and progress of biodegradation of MTBE between 2008 and 2013. The TBA observed in 2008 appears to be derived only in part from MTBE transformation while a significant portion of TBA might be contributed directly from LNAPL sources. In 2011 to 2013, the dominant source of TBA in the mid‐gradient plume was MTBE transformation. A contribution of an offsite LNAPL source, in particular to the down‐gradient area of the plume, is possible but could not be unequivocally confirmed. The time series provided direct evidence for MTBE biodegradation, but also a valuable insight on the sources of TBA.
Thermal DNAPL Source Zone Treatment Impact on a CVOC Plume
Authors: Heron Gorm , Bierschenk John , Swift Robin , Watson Robert , Kominek Michael
Published: March 2018

The tetrachloroethene (PCE) source zone at a site in Endicott, New York had caused a dissolved PCE plume. This plume was commingled with a petroleum hydrocarbon plume from an upgradient source of fuel oil. The plume required a system for hydraulic containment, using extraction wells located about 360 m downgradient of the source. The source area was remediated using in situ thermal desorption (ISTD). Approximately 1406 kilograms (kg) of PCE was removed in addition to 4082 kg of commingled petroleum‐related compounds. The ISTD treatment reduced the PCE mass discharge into the plume from an estimated 57 kg/year to 0.07 kg/year, essentially removing the source term. In the 5 years following the completion of the thermal treatment in early 2010, the PCE plume has collapsed, and the concentration of degradation products in the PCE‐series plume area has declined by two to three orders of magnitude. Anaerobic dechlorination is the suspected dominant mechanism, assisted by the presence of a fuel oil smear zone and a petroleum hydrocarbon plume from a separate source area upgradient of the PCE source. Based on the post‐thermal treatment groundwater monitoring data, the hydraulic containment system was reduced in 2014 and discontinued in early 2015.
Field Tracer Test for the Design of LNAPL Source Zone Surfactant Flushing
Authors: Robert Thomas , Martel Richard , Lefebvre René , Lauzon Jean‐Marc , Morin Annie
Published: March 2018

A field tracer test was carried out in a light nonaqueous phase liquid (LNAPL) source zone using a well pattern consisting of one injection well surrounded by four extraction wells (5‐spot well pattern). Multilevel sampling was carried out in two observation wells located inside the test cell characterized by heterogeneous lithology. Tracer breakthrough curves showed relatively uniform flow within soil layers. A numerical flow and solute transport model was calibrated on hydraulic heads and tracer breakthrough curves. The model was used to estimate an average accessible porosity of 0.115 for the swept zone and an average longitudinal dispersivity of 0.55 m. The model was further used to optimize the relative effects of viscous forces versus capillary forces under realistic imposed hydraulic gradients and to establish optimal surfactant solution properties. Maximum capillary number (NCa) values between injection and extraction wells were obtained for an injection flow rate of 16 L/min, a total extraction flow rate of 20 L/min, and a surfactant solution with a viscosity of 0.005 Pa⋅s. The unconfined nature of the aquifer limited further flow rate or viscosity increases that would have led to unrealistic hydraulic gradients. An NCa range of 3.8 × 10−4 to 7.6 × 10−3 was obtained depending on the magnitude of the simulated LNAPL‐water interfacial tension reduction. Finally, surfactant and chase water slug sizing was optimized with a radial form of the simplified Ogata‐Banks analytical solution (Ogata and Banks 1961) so that injected concentrations could be maintained in the entire 5‐spot cell.
An Empirical Evaluation of the Influence of Ethanol on Natural Attenuation of Gasoline Constituents
Authors: O'Reilly Kirk , Espino Devine Catalina , Sihota Natasha , North Katharine
Published: March 2018

Since the 1990s, questions have arisen as to whether the release of ethanol‐blended fuel will inhibit natural attenuation of other gasoline constituents in groundwater. This study evaluated the hypothesis that ethanol affects hydrocarbon attenuation and whether the use of ethanol‐blended fuel alters the applicability of monitored natural attenuation (MNA) as an approach for managing risks at fuel‐release sites. Groundwater data from California's GeoTracker database were used to compare attenuation of benzene, toluene, methyl tert‐butyl ether (MTBE), and tert‐butyl alcohol (TBA) at sites with and without detections of ethanol. Excel‐based tools were developed to conduct attenuation evaluations on thousands of wells simultaneously. Ethanol was detected at least once in 4.5% of the wells and 0.6% of the samples of which it was analyzed. The distribution of Mann‐Kendall concentration trend analysis results and first‐order attenuation rates were essentially the same at sites with or without ethanol detections. Median plume lengths were shorter at sites where ethanol had not been detected compared to sites where ethanol was detected (36 vs. 43 m for benzene; 36 vs. 42 m for toluene; 43 vs. 52 m for MTBE; and 44 vs. 59 m for TBA). However, the distribution of plume lengths was similar irrespective of ethanol concentrations, suggesting other factors may influence plume elongation. Finally, while anaerobic ethanol degradation can result in methane generation, the distributions of methane concentrations were the same at sites with and without ethanol detections. These results suggest that the use of ethanol‐blended fuel should not limit the application of MNA at most biodegrading fuel‐release sites.
Comparison of Oil Transmissivity Methods Using Bail‐Down Test Data
Authors: Palmier Cédric , Dodt Matthew , Atteia Olivier
Published: March 2018

This paper evaluates the results from three methods commonly used to estimate oil transmissivity: the modified Cooper solution (Beckett and Lyverse 2002), the modified Bouwer and Rice method (Kirkman 2013), and the modified Jacob and Lohman method (Huntley 2000). Determining the validity of oil transmissivity values is important (e.g., when used in extraction system design and operation) and not straightforward as these methods are based on different assumptions and boundary conditions and introduce different simplifying assumptions to allow for estimating oil drawdown. Data from 289 bail‐down tests performed during an oil remediation project were used in this evaluation. Analysis of these tests produced realistic transmissivity values and good correlation between these three methods, giving the authors confidence in the oil transmissivity values as this correlation is reflected across a significant number of data sets. Secondly, the nature of oil and water recharge to the wells interpreted from Kirkman's J‐ratio values largely validates the Huntley (2000) simplifying assumption that the potentiometric surface will be relatively constant during the test, allowing the use of the modified Bouwer and Rice method. Finally, the impact of oil extraction on measured oil thickness and estimated oil transmissivity was also assessed. The study showed a clear general decrease in both measured oil thicknesses and estimated oil transmissivity during the oil recovery project. However, measured oil thickness and estimated oil transmissivity are not clearly correlated, and, as a consequence, the range of decrease in one parameter does not allow any prediction of the range of decrease in the second parameter.
Utility of Compound‐Specific Isotope Analysis for Vapor Intrusion Investigations
Authors: Beckley Lila , McHugh Thomas , Philp Paul
Published: March 2018

Different types of data can be collected to evaluate whether or not vapor intrusion is a concern at sites impacted with volatile organic compound (VOC) contamination in the subsurface. Typically, groundwater, soil gas, or indoor air samples are collected to determine VOC concentrations in the different media. Sample results are evaluated using a “multiple lines of evidence” approach to interpret whether vapor intrusion is occurring. Data interpretation is often not straightforward because of many complicating factors, particularly in the evaluation of indoor air. More often than not, indoor air sample results are affected by indoor or other background sources making interpretation of concentration‐based data difficult using conventional sampling approaches. In this study, we explored the practicality of compound‐specific isotope analysis (CSIA) as an additional type of evidence to distinguish between indoor sources and subsurface sources (i.e., vapor intrusion). We developed a guide for decision‐making to facilitate data interpretation and applied the guidelines at four different test buildings. To evaluate the effectiveness of the CSIA method for vapor intrusion applications, we compared the interpretation from CSIA to interpretations based on data from two different investigation approaches: conventional sampling and on‐site GC/MS analysis. Interpretations using CSIA were found to be generally consistent with the other approaches. In one case, CSIA provided the strongest line of evidence that vapor intrusion was not occurring and that a VOC source located inside the building was the source of VOCs in indoor air.
Cryogenic Core Collection (C3) from Unconsolidated Subsurface Media
Authors: Kiaalhosseini Saeed , Johnson Richard L. , Rogers Richard C. , Renno Maria Irianni , Lyverse Mark , Sale Thomas C.
Published: March 2018

We evaluated tools and methods for in situ freezing of cores in unconsolidated subsurface media. Our approach, referred to as cryogenic core collection (C3), has key aspects that include downhole circulation of liquid nitrogen (LN) via a cooling system, strategic use of thermal insulation to focus cooling into the core, and controlling LN back pressure to optimize cooling. Two cooling systems (copper coil and dual‐wall cylinder) are described. For both systems, the time to freeze a single 2.5‐foot (76‐cm) long by 2.5‐inch (63‐mm) diameter core is 5 to 7 min. Frozen core collection rates of about 30 feet/day (10 m/day) were achieved at two field sites, one impacted by petroleum‐based light nonaqueous phase liquids (LNAPLs) and the other by chlorinated solvents. Merits of C3 include (1) improved core recovery, (2) potential control of flowing sand, and (3) improved preservation of critical sediment attributes. Development of the C3 method creates novel opportunities to characterize sediment with respect to physical, chemical, and biological properties. For example, we were able to resolve water, LNAPL, and gas saturations above and below the water table. By eliminating drainage of water, gas and LNAPL saturations in the range of 6 to 23% and 1 to 3% of pore space, respectively, were measured in LNAPL‐impacted intervals below the water table.
Total Dissolved Gas Pressure Measurements for Assessing Contaminant Degradation Processes in Groundwater
Authors: Roy James W. , McLeod Heather C. , Suchy Martin , Smith James E.
Published: March 2018

The total dissolved gas pressure (PTDG) probe has been used in groundwater studies for over a decade, but rarely in assessing contaminant degradation, despite the many degradation reactions that produce or consume dissolved gases. Here we present three studies to demonstrate the application ofPTDGmeasurements to groundwater experiencing contaminant degradation, with discussion of its benefits and limitations. The first study is a pilot‐scale laboratory experiment simulating dissolved ethanol contamination of an anaerobic sand aquifer. Continuous monitoring ofPTDGshowed the rapid onset of microbial hydrocarbon degradation via denitrification and fermentation. The subsequent formation of a gas phase was revealed whenPTDGbegan mimicking the bubbling pressure (PG*; sum of hydrostatic and atmospheric pressure), fluctuating with atmospheric pressure. Some deviations ofPTDGabovePG* occurred also, which may hold promise for signalling substantial changes in the rate or type of degradation process (here, the onset of methanogenesis). In the second study, synoptic field measurements at a petroleum plume site demonstrated how elevatedPTDGcould identify wells with evidence of hydrocarbon degradation (denitrification and/or methanogenesis). And finally, combined field measurements ofdissolved oxygen (DO)andPTDGin monitoring wells of a nitrate‐contaminated aquifer (Abbottsford‐Sumas) revealed areas where denitrification was likely occurring. Limitations toPTDGuse identified in these studies included the masking of degradation processes by the presence of a gas phase, as when trapped following water table fluctuations or formed from rigorous degradation reactions, and confounded assessment ofPTDGpatterns from other natural or anthropogenic processes that can also influence groundwaterPTDG.
Bioaugmentation in a Well‐Characterized Fractured Rock DNAPL Source Area
Authors: Schaefer Charles E. , Lavorgna Graig M. , White Erin B. , Annable Michael D.
Published: March 2018

A field demonstration was performed at Edwards Air Force Base to assess bioaugmentation for treatment of a well‐characterized tetrachloroethene (PCE) dense nonaqueous phase liquid (DNAPL) source area in fractured rock. Groundwater recirculation was employed to deliver remedial amendments, including bacteria, to facilitate reductive dechlorination and enhance DNAPL dissolution. An active treatment period of 9 months was followed by a 10‐month posttreatment rebound evaluation. Dechlorination daughter products were observed in both the shallow and deep fracture zones following treatment. In the shallow fracture zone, the calculated DNAPL mass removed was approximately equal to the DNAPL mass estimated using partitioning tracer testing, and no rebound in chlorinated ethenes or ethene was observed during the posttreatment period. A maximum DNAPL dissolution enhancement factor of 5 was observed in the shallow fracture zone. In the deep fracture zone, only approximately 45% of the DNAPL mass—as estimated via partitioning tracer testing—was removed and rebound in the total molar chlorinated ethenes + ethene was observed. The difference in behavior between the shallow and deep fracture zones was attributed to DNAPL architecture and the fracture flow field.
Performance Assessment of Pump‐and‐Treat Systems
Authors: Truex Michael , Johnson Chris , Macbeth Tamzen , Becker Dave , Lynch Kira , Giaudrone Dominic , Frantz, Aaron , Lee Hope
Published: March 2018

Pump‐and‐treat (P&T) is a widely applied remedy for groundwater remediation at many types of sites for multiple types of contaminants. Decisions regarding major changes in the remediation approach are an important element of environmental remediation management for a site using P&T. While existing guidance documents provide information on design, operation, and optimization for P&T systems, these documents do not provide specific technical guidance to support remedy decisions regarding when to transition to a new remedy or to initiate closure of the P&T remedy. A structured approach for P&T performance assessment was developed and is described herein, using analysis of three example P&T systems. These examples highlight key aspects of the performance assessment decision logic and represent assessment outcomes associated with optimizing the P&T system, transitioning from P&T to natural attenuation, and supplementing P&T with another technology to hasten transition to natural attenuation.
Interface Treatment of Petroleum Hydrocarbon‐impacted Lower Permeability Layers by Activated Sodium Persulfate to Reduce Emissions to Groundwater
Authors: Cavanagh Bridget A. , Wilson Sean T. , Johnson Paul C. , Daniels Eric J.
Published: March 2018

Nonaqueous phase liquid (NAPL)‐impacted lower permeability layers in heterogeneous media are difficult to fully remediate and can act as persistent sources of groundwater contamination through diffusive emissions to transmissive aquifer zones. This work investigated the benefits of partial remediation involving treatment focused near the high‐low permeability interface, with the performance metric being emissions reduction. A sequential base‐activated persulfate (S2O8
2−) delivery treatment strategy was studied in this work, involving 13–14 d deliveries of 10% w/w sodium persulfate (Na2S2O8) and 14–28 d deliveries of 19 g/L sodium hydroxide (NaOH). Treatment and control experiments were conducted in 1.2‐m wide × 1.2‐m tall × 5‐cm thick physical model tanks containing two soil layers differing in hydraulic conductivity by three orders of magnitude. The top 10 cm of the lower permeability layers contained 7400–7800 mg‐NAPL/kg‐soil; the NAPL was comprised of benzene, toluene, ethylbenzene, p‐xylene, o‐xylene, n‐propylbenzene, and 1,3,5‐trimethylbenzene (TMB) mixed in octane. Approximately 0.1 g‐Na2S2O8 was delivered per cm2‐interface area over 13–14 d. The S2O8
2− and SO4
2− concentration profiles suggest higher oxidant reaction rates when NaOH is delivered prior to, rather than after Na2S2O8. After 264 d and two treatments, hydrocarbon emissions from the NAPL source were reduced by 60% to 73% compared to a no‐treatment control tank. The incremental benefit of the second treatment was only about 10% of the effect of the first treatment.