Rare Earth Element Adsorption to Clay Minerals: Mechanistic Insights and Implications for Recovery from Secondary Sources.

The energy transition will have significant mineral demands and there is growing interest in recovering critical metals, including rare earth elements (REE), from secondary sources in aqueous and sedimentary environments. However, the role of clays in REE transport and deposition in these settings remains understudied. This work investigated REE adsorption to the clay minerals illite and kaolinite through pH adsorption experiments and extended X-ray absorption fine structure (EXAFS). Clay type, pH, and ionic strength (IS) affected adsorption, with decreased adsorption under acidic pH and elevated IS. Illite had a higher adsorption capacity than kaolinite; however, >95% adsorption was achieved at pH ∼7.5 regardless of IS or clay. These results were used to develop a surface complexation model with the derived binding constants used to predict REE speciation in the presence of competing sorbents. This demonstrated that clays become increasingly important as pH increases, and EXAFS modeling showed that REE can exist as both inner- and outer-sphere complexes. Together, this indicated that clays can be an important control on the transport and enrichment of REE in sedimentary systems. These findings can be applied to identify settings to target for resource extraction or to predict REE transport and fate as a contaminant.

Exposure to Hydraulic Fracturing Flowback Water Impairs Mahi-Mahi (Coryphaena hippurus) Cardiomyocyte Contractile Function and Swimming Performance.

Publicly available toxicological studies on wastewaters associated with unconventional oil and gas (UOG) activities in offshore regions are nonexistent. The current study investigated the impact of hydraulic fracturing-generated flowback water (HF-FW) on whole organism swimming performance/respiration and cardiomyocyte contractility dynamics in mahi-mahi (Coryphaena hippurus-hereafter referred to as "mahi"), an organism which inhabits marine ecosystems where offshore hydraulic fracturing activity is intensifying. Following exposure to 2.75% HF-FW for 24 h, mahi displayed significantly reduced critical swimming speeds (Ucrit) and aerobic scopes (reductions of ∼40 and 61%, respectively) compared to control fish. Additionally, cardiomyocyte exposures to the same HF-FW sample at 2% dilutions reduced a multitude of mahi sarcomere contraction properties at various stimulation frequencies compared to all other treatment groups, including an approximate 40% decrease in sarcomere contraction size and a nearly 50% reduction in sarcomere relaxation velocity compared to controls. An approximate 8-fold change in expression of the cardiac contractile regulatory gene cmlc2 was also seen in ventricles from 2.75% HF-FW-exposed mahi. These results collectively identify cardiac function as a target for HF-FW toxicity and provide some of the first published data on UOG toxicity in a marine species.

Males and females exhibit similar muscle glycogen recovery with varied recovery food sources.

PURPOSE: Research has elucidated the impact of post-exercise carbohydrate nutrition and environmental conditions on muscle glycogen re-synthesis. However, research has minimally considered the implications of glycogen recovery in females and has mostly focused on commercial sport nutrition products. The purpose of this study was to determine the effects of varied mixed macronutrient feedings on glycogen recovery and subsequent exercise performance in both sexes. METHODS: Males (n = 8) and females (n = 8) participated in a crossover study. Subjects completed a 90-min cycling glycogen depletion trial, then rested for 4 h. Two carbohydrate feedings (1.6 g kg-1) of either sport supplements or potato-based products were delivered at 0 and 2 h post-exercise. Muscle biopsies (glycogen) and blood samples (glucose, insulin) were collected during the recovery. Afterwards, subjects completed a 20 km cycling time trial. RESULTS: There was no difference between sexes or trials for glycogen recovery rates (male: 7.9 ± 2.7, female: 8.2 ± 2.7, potato-based: 8.0 ± 2.5, sport supplement: 8.1 ± 3.1 mM kg wet wt-1 h-1, p > 0.05). Time trial performance was not different between diets (38.3 ± 4.4 and 37.8 ± 3.9 min for potato and sport supplement, respectively, p > 0.05). CONCLUSIONS: These results indicate that food items, such as potato-based products, can be as effective as commercially marketed sports supplements when developing glycogen recovery oriented menus and that absolute carbohydrate dose feedings (g kg-1) can be effectively applied to both males and females.

Toxicity in aquatic model species exposed to a temporal series of three different flowback and produced water samples collected from a horizontal hydraulically fractured well.

In the present study, we compared the toxicity and associated chemical characterizations of flowback and produced water (FPW) collected from a single horizontal hydraulically fractured well at different time points during FPW production. Since few studies on whole mixture toxicity related to FPW exist, our aims were to determine both overall toxicity of the FPW mixture in a suite of organisms (Daphnia magna, Lumbriculus variegatus, Danio rerio, and Oncorhynchus mykiss) and also determine if toxicity changes depending on variation in FPW chemical properties as a function of time sampled (1.33, 72, and 228 h FPW samples collected immediately post-well production onset were analyzed in current study). FPW chemical composition was determined via quadra-pole inductively coupled plasma - mass spectrometry/mass spectrometry (ICP-MS/MS), full-scan high performance liquid chromatography/Orbitrap mass spectrometry (HPLC/Orbitrap-MS), and gas chromatography-mass spectrometry (GC-MS). We observed that FPW sampled later in the production process contained higher ion and total dissolved solids concentrations, whereas the highest concentrations of dissolved organic compounds were observed in the earliest FPW sample analyzed. Toxicity associated with FPW exposure was deemed to be species-specific to a certain extent, but general trends revealed the earliest FPW sampled contained highest toxic potential. Accordingly, we theorize that although the saline conditions of FPW are the foremost toxicological drivers to freshwater organisms, dissolved organics associated with FPW significantly contribute to the overall toxicity of exposed organisms.

Thermodynamic Analysis of Nickel(II) and Zinc(II) Adsorption to Biochar.

While numerous studies have investigated metal uptake from solution by biochar, few of these have developed a mechanistic understanding of the adsorption reactions that occur at the biochar surface. In this study, we explore a combined modeling and spectroscopic approach for the first time to describe the molecular level adsorption of Ni(II) and Zn(II) to five types of biochar. Following thorough characterization, potentiometric titrations were carried out to measure the proton (H+) reactivity of each biochar, and the data was used to develop protonation models. Surface complexation modeling (SCM) supported by synchrotron-based extended X-ray absorption fine structure (EXAFS) was then used to gain insights into the molecular scale metal-biochar surface reactions. The SCM approach was combined with isothermal titration calorimetry (ITC) data to determine the thermodynamic driving forces of metal adsorption. Our results show that the reactivity of biochar toward Ni(II) and Zn(II) directly relates to the site densities of biochar. EXAFS along with FT-IR analyses, suggest that Ni(II) and Zn(II) adsorption occurred primarily through proton-active carboxyl (-COOH) and hydroxyl (-OH) functional groups on the biochar surface. SCM-ITC analyses revealed that the enthalpies of protonation are exothermic and Ni(II) and Zn(II) complexes with biochar surface are slightly exothermic to slightly endothermic. The results obtained from these combined approaches contribute to the better understanding of molecular scale metal adsorption onto the biochar surface, and will facilitate the further development of thermodynamics-based, predictive approaches to biochar removal of metals from contaminated water.

Sublethal and Reproductive Effects of Acute and Chronic Exposure to Flowback and Produced Water from Hydraulic Fracturing on the Water Flea Daphnia magna.

Hydraulic fracturing is an industrial process allowing for the extraction of gas or oil. To fracture the rocks, a proprietary mix of chemicals is injected under high pressure, which later returns to the surface as flowback and produced water (FPW). FPW is a complex chemical mixture consisting of trace metals, organic compounds, and often, high levels of salts. FPW toxicity to the model freshwater crustacean Daphnia magna was characterized utilizing acute (48 h median lethal concentrations; LC50) and chronic (21 day) exposures. A decrease in reproduction was observed, with a mean value of 18.5 neonates produced per replicate over a 21 day chronic exposure to 0.04% FPW, which was a significant decrease from the average of 64 neonates produced in the controls. The time to first brood was delayed in the highest FPW (0.04%) treatment. Neonates exhibited an LC50 of 0.19% of full-strength FPW, making them more sensitive than adults, which displayed an LC50 value of 0.75%. Quantitative PCR highlighted significant changes in expression of genes encoding xenobiotic metabolism (cyp4) and moulting (cut). This study is the first to characterize chronic FPW toxicity and will help with the development of environmental monitoring and risk assessment of FPW spills.

Targeting Wnt-driven cancer through the inhibition of Porcupine by LGK974.

Wnt signaling is one of the key oncogenic pathways in multiple cancers, and targeting this pathway is an attractive therapeutic approach. However, therapeutic success has been limited because of the lack of therapeutic agents for targets in the Wnt pathway and the lack of a defined patient population that would be sensitive to a Wnt inhibitor. We developed a screen for small molecules that block Wnt secretion. This effort led to the discovery of LGK974, a potent and specific small-molecule Porcupine (PORCN) inhibitor. PORCN is a membrane-bound O-acyltransferase that is required for and dedicated to palmitoylation of Wnt ligands, a necessary step in the processing of Wnt ligand secretion. We show that LGK974 potently inhibits Wnt signaling in vitro and in vivo, including reduction of the Wnt-dependent LRP6 phosphorylation and the expression of Wnt target genes, such as AXIN2. LGK974 is potent and efficacious in multiple tumor models at well-tolerated doses in vivo, including murine and rat mechanistic breast cancer models driven by MMTV-Wnt1 and a human head and neck squamous cell carcinoma model (HN30). We also show that head and neck cancer cell lines with loss-of-function mutations in the Notch signaling pathway have a high response rate to LGK974. Together, these findings provide both a strategy and tools for targeting Wnt-driven cancers through the inhibition of PORCN.

High-density lipoprotein cholesterol levels in middle-school children: association with cardiovascular risk factors and lifestyle behaviors.

To examine factors associated with low high-density lipoprotein cholesterol (HDL-C) levels among middle school children. HDL-C levels were the primary outcome of interest. A total of 1,104 middle-school children (mean age 11.6 years, 51.2% female) were included in this analysis, of whom 177 (16%) had an HDL-C level ≤40 mg/dL. More than half of those with low HDL-C were overweight or obese (62.2%) and had greater systolic and diastolic blood pressure, triglyceride (TRG) levels, and low-density lipoprotein cholesterol levels compared with children with an HDL-C level >40 mg/dL. Among those with an HDL-C ≤ 40 mg/dL, 35% also had body mass index ≥85% and TRG levels ≥150 mg/dL. Exercise habits were significantly associated with HDL-C level, whereas sedentary behaviors, such as screen time, were not significantly associated with HDL-C level. Fruit and vegetable intake was also not significantly associated with HDL-C level. Children with low HDL-C levels are more likely to be overweight and to have other physiological indicators of increased cardiovascular risk. Further research is needed to determine if school-based interventions can result in long-term improvements in HDL-C.

Spatial and temporal variation in toxicity and inorganic composition of hydraulic fracturing flowback and produced water.

Hydraulic fracturing for oil and gas extraction produces large volumes of wastewater, termed flowback and produced water (FPW), that are highly saline and contain a variety of organic and inorganic contaminants. In the present study, FPW samples from ten hydraulically fractured wells, across two geologic formations were collected at various timepoints. Samples were analyzed to determine spatial and temporal variation in their inorganic composition. Results indicate that FPW composition varied both between formations and within a single formation, with large compositional changes occurring over short distances. Temporally, all wells showed a time-dependent increase in inorganic elements, with total dissolved solids increasing by up to 200,000 mg/L over time, primarily due to elements associated with salinity (Cl, Na, Ca, Mg, K). Toxicological analysis of a subset of the FPW samples showed median lethal concentrations (LC50) of FPW to the aquatic invertebrate Daphnia magna were highly variable, with the LC50 values ranging from 1.16% to 13.7% FPW. Acute toxicity of FPW significantly correlated with salinity, indicating salinity is a primary driver of FPW toxicity, however organic components also contributed to toxicity. This study provides insight into spatiotemporal variability of FPW composition and illustrates the difficulty in predicting aquatic risk associated with FPW.

Enhancing teen pregnancy prevention in local communities: capacity building using the interactive systems framework.

Getting To Outcomes (GTO), an innovative framework for planning, implementing, evaluating, and sustaining interventions has been shown to be effective in helping community-based organizations (CBOs) introduce science-based approaches into their prevention work. However, the Interactive Systems Framework (ISF) suggests that adopting innovations like GTO requires a significant amount of capacity building through training and technical assistance (T/TA). In this study, 11 CBOs and three schools in South Carolina entered into a 3 year program of intense and proactive T/TA based on the ISF to learn how to apply an adaptation of GTO (Promoting Science-Based Approaches-Getting To Outcomes, PSBA-GTO) to their teen pregnancy prevention programs. Using semi-structured interviews, the partnering organizations were assessed at three points in time, pre-T/TA, 12 months, and post T/TA (30 months) for their performance of the steps of GTO in their work. The seven organizations which participated in T/TA until the end of the project received an average of 76 h of TA and 112 h of training per organization. Interview results showed increased performance of all 10 steps of PSBA-GTO by these organizations when conducting their teen pregnancy programs. These results suggest targeted and proactive T/TA can successfully bridge the gap between research and practice by using a three part delivery system, as prescribed in the ISF, which relies on an intermediary prevention support system to ensure accurate and effective translation of research to the everyday work of community-based practitioners.

Lead (Pb) sorption to hydrophobic and hydrophilic zeolites in the presence and absence of MTBE.

The co-contamination of the environment by metals and organic pollutants is a significant concern, and one such example is lead (Pb) and methyl tert-butyl ether (MTBE) due to their historic use as fuel additives. Clinoptilolite is an abundant and efficient zeolite for metal removal, but the potential interference of co-existing organic pollutants on metal removal, such as MTBE, have rarely been discussed. In this study, a combination of batch sorption tests and synchrotron-based X-ray absorption spectroscopic analyses were employed to investigate Pb sorption mechanism(s) onto clinoptilolite in the presence and absence of MTBE. A comparison was made to synthetic ZSM-5 zeolite to gain insights into differences in Pb binding mechanisms between hydrophilic (clinoptilolite) and hydrophobic (ZSM-5) zeolites. Site occupancy and surface precipitation contributed equally to Pb removal by clinoptilolite, while surface precipitation was the main Pb removal mechanism for ZSM-5 followed by site occupancy. Despite the negligible effect of 100 mg/L MTBE on observed Pb removal from solution by both zeolites, a surface-embedded Pb removal mechanism, through the Mg site on clinoptilolite surface, arises when MTBE is present. This study provides an understanding of atomic-level Pb uptake mechanisms on zeolites, with and without co-contaminating MTBE, which aids in their application in water treatment at co-contaminated sites.

Understanding the effects of hydraulic fracturing flowback and produced water (FPW) to the aquatic invertebrate, Lumbriculus variegatus under various exposure regimes.

Hydraulic fracturing of horizontal wells is a cost effective means for extracting oil and gas from low permeability formations. Hydraulic fracturing often produces considerable volumes of flowback and produced water (FPW). FPW associated with hydraulic fracturing has been shown to be a complex, often brackish mixture containing a variety of anthropogenic and geogenic compounds. In the present study, the risk of FPW releases to aquatic systems was studied using the model benthic invertebrate, Lumbriculus variegatus and field-collected FPW from a fractured well in Alberta. Acute, chronic, and pulse toxicity were evaluated to better understand the implications of accidental FPW releases to aquatic environments. Although L.variegatus is thought to have a high tolerance to many stressors, acute toxicity was significant at low concentrations (i.e. high dilutions) of FPW (48 h LC50: 4-5%). Chronic toxicity (28 d)of FPW in this species was even more pronounced with LC50s (survival/reproduction) and EC50s (total mass) at dilutions as low as 0.22% FPW. Investigations evaluating pulse toxicity (6 h and 48 h exposure) showed a significant amount of latent mortality occurring when compared to the acute results. Additionally, causality in acute and chronic bioassays differed as acute toxicity appeared to be primarily driven by salinity, which was not the case for chronic toxicity, as other stressors appear to be important as well. The findings of this study show the importance of evaluating multiple exposure regimes, the complexity of FPW, and also shows the potential aquatic risk posed by FPW releases.

Characterization and implications of solids associated with hydraulic fracturing flowback and produced water from the Duvernay Formation, Alberta, Canada.

Public concern is heightened around flowback and produced water (FPW) generated by the hydraulic fracturing process. FPW is a complex mix of organic and inorganic solutes derived from both the injected hydraulic fracturing fluid and interactions with the subsurface lithology. Few studies to date have systematically investigated the composition of FPW or its individual components. Here, we provide the first systematic characterization of the composition of the solids associated with FPW by analyzing samples from three wells drilled into the Duvernay Formation in Alberta, Canada. The FPW initially returned to the surface with high total dissolved solids (greater than 170 000 mg L-1) and enriched with Fe(ii), silica, sulfate, barium, and strontium. The solids form two distinct phases once the FPW reached the surface: (1) silica-enriched Fe(iii) oxyhydroxides, and (2) a barite-celestine solid solution. We hypothesize that the precipitation of the amorphous silica-enriched Fe(iii) oxyhydroxide is a two-step process, where first the silica precipitates as a function of the cooling of the FPW from elevated subsurface temperatures to ambient surface temperatures. Next, the silica acts as a template for the precipitation of Fe(iii) oxyhydroxide as the diffusion of oxygen into the subsurface causes oxidation of aqueous Fe(ii). The barite-celestine solid solution precipitates solely as a function of cooling. Elevated dissolved Fe concentrations in FPW and modeled saturation indices from five North American shale plays (Marcellus, Fayetteville, Barnett, Bakken, and Denver-Julesburg) indicate that solids similar to those found in Duvernay FPW, specifically Fe(iii) oxyhydroxides, barite and quartz, are likely to occur. With the solids known to carry a significant portion of FPW's toxicity and organic contaminant load, the development of new treatment technologies, such as the oxidation of the Fe(ii) in FPW, may increase FPW reuse and reduce the environmental risk posed by FPW.

Cadmium bioaccumulates after acute exposure but has no effect on locomotion or shelter-seeking behaviour in the invasive green shore crab (Carcinus maenas).

Cadmium (Cd2+) is a non-essential metal ubiquitous in the environment due to industrial processes. However, little is known regarding the ability of Cd2+ to impact the behaviour of aquatic animals in receiving environments. Green shore crabs (Carcinus maenas) were exposed to waterborne Cd2+ [control (no Cd2+), low (0.30 µmol/L), medium (3.3 µmol/L) and high (63 µmol/L)], for 24 h, then, crabs were placed in an open field and shelter test to determine potential changes in locomotion and preference for shelter. Tissues (gill, haemolymph, stomatogastric ganglion) were taken for bioaccumulation analysis of Cd2+ and ion content. Behavioural testing was recorded with a motion-tracking software system and showed no impact of Cd2+ on any variable in either of the tests used. All three tissues accumulated Cd2+ in a concentration-dependent manner. Crabs exposed to low Cd2+ showed a small but significant decrease in haemolymph Ca2+, however, this effect was not present at higher Cd2+ exposures. Overall, the results indicate that short-term Cd2+ exposure, and the resulting Cd2+ accumulation, had no effect on locomotor and anxiety-related behaviour of green shore crabs.

Chemical and toxicological characterizations of hydraulic fracturing flowback and produced water.

Hydraulic fracturing (HF) has emerged as a major method of unconventional oil and gas recovery. The toxicity of hydraulic fracturing flowback and produced water (HF-FPW) has not been previously reported and is complicated by the combined complexity of organic and inorganic constituents in HF fluids and deep formation water. In this study, we characterized the solids, salts, and organic signatures in an HF-FPW sample from the Duvernay Formation, Alberta, Canada. Untargeted HPLC-Orbitrap revealed numerous unknown dissolved polar organics. Among the most prominent peaks, a substituted tri-phenyl phosphate was identified which is likely an oxidation product of a common polymer antioxidant. Acute toxicity of zebrafish embryo was attributable to high salinity and organic contaminants in HF-FPW with LC50 values ranging from 0.6% to 3.9%, depending on the HF-FPW fractions and embryo developmental stages. Induction of ethoxyresorufin-O-deethylase (EROD) activity was detected, due in part to polycyclic aromatic hydrocarbons (PAHs), and suspended solids might have a synergistic effect on EROD induction. This study demonstrates that toxicological profiling of real HF-FPW sample presents great challenges for assessing the potential risks and impacts posed by HF-FPW spills.

Using data to improve fidelity when implementing evidence-based programs.

In fall 2011, the South Carolina Campaign to Prevent Teen Pregnancy (SC Campaign), with funding from Office of Adolescent Health, began replicating an evidence-based curriculum, It's Your Game, Keep It Real in 12 middle schools across South Carolina. Fidelity of the curriculum was monitored by the use of lesson fidelity logs completed by curriculum facilitators and lesson observation logs submitted by independent classroom observers. These data were monitored weekly to identify possible threats to fidelity. The innovative model Fidelity Through Informed Technical Assistance and Training was developed by SC Campaign to react to possible fidelity threats in real time, through a variety of technical assistance modalities. Fidelity Through Informed Technical Assistance and Training guided the 55 hours of technical assistance delivered by the SC Campaign during the first year of It's Your Game, Keep It Real implementation to 18 facilitators across 12 SC middle schools, and achieved 98.4% curriculum adherence and a high quality of implementation scores.

Genetic variation at the TNF-alpha promoter and malaria susceptibility in rhesus (Macaca mulatta) and long-tailed (Macaca fascicularis) macaques.

Polymorphisms within the promoter region of the TNF-alpha gene have been associated with altered expression of TNF-alpha and susceptibility to a variety of diseases in humans. Although macaques (Macaca spp.) are frequently used as models to study human diseases, little is known about the extent of genetic variation at the TNF-alpha locus and its consequences for disease susceptibility in these species. The TNF-alpha promoter region was sequenced in a sample of 40 macaques including five M. mulatta of Chinese and Indian ancestry and 35 M. fascicularis of Malaysian, Mauritian, Indonesian, and Philippine ancestry. These groups were chosen because they exhibit differences in their susceptibilities to severe malaria upon infection with Plasmodium parasites. Sequence analysis revealed a total of 14 single nucleotide polymorphisms (SNPs), five of which are newly described, and 20 unique haplotypes. In addition, the TFSEARCH program was used to investigate the potential of these polymorphisms to influence transcription factor binding. While both species exhibited a similarly high degree of genetic variability at the TNF-alpha promoter, AMOVA analysis and FST values indicated that most of the variation is shared between species and among populations. However, two of the most common haplotypes, describing 31.7% of the observed variation, and three potentially functional polymorphisms at positions -781, -535, and -10, were exclusive to M. fascicularis. Polymorphisms in the human ortholog of the TNF-alpha promoter which are known to be associated with malaria susceptibility in humans were not shared with macaques.

Characterization of two tetrachloroethene-reducing, acetate-oxidizing anaerobic bacteria and their description as Desulfuromonas michiganensis sp. nov.

Two tetrachlorethene (PCE)-dechlorinating populations, designated strains BB1 and BRS1, were isolated from pristine river sediment and chloroethene-contaminated aquifer material, respectively. PCE-to-cis-1,2-dichloroethene-dechlorinating activity could be transferred in defined basal salts medium with acetate as the electron donor and PCE as the electron acceptor. Taxonomic analysis based on 16S rRNA gene sequencing placed both isolates within the Desulfuromonas cluster in the delta subdivision of the Proteobacteria. PCE was dechlorinated at rates of at least 139 nmol min(-1) mg of protein(-1) at pH values between 7.0 and 7.5 and temperatures between 25 and 30 degrees C. Dechlorination also occurred at 10 degrees C. The electron donors that supported dechlorination included acetate, lactate, pyruvate, succinate, malate, and fumarate but not hydrogen, formate, ethanol, propionate, or sulfide. Growth occurred with malate or fumarate alone, whereas oxidation of the other electron donors depended strictly on the presence of fumarate, malate, ferric iron, sulfur, PCE, or TCE as an electron acceptor. Nitrate, sulfate, sulfite, thiosulfate, and other chlorinated compounds were not used as electron acceptors. Sulfite had a strong inhibitory effect on growth and dechlorination. Alternate electron acceptors (e.g., fumarate or ferric iron) did not inhibit PCE dechlorination and were consumed concomitantly. The putative fumarate, PCE, and ferric iron reductases were induced by their respective substrates and were not constitutively present. Sulfide was required for growth. Both strains tolerated high concentrations of PCE, and dechlorination occurred in the presence of free-phase PCE (dense non-aqueous-phase liquids). Repeated growth with acetate and fumarate as substrates yielded a BB1 variant that had lost the ability to dechlorinate PCE. Due to the 16S rRNA gene sequence differences with the closest relatives and the unique phenotypic characteristics, we propose that the new isolates are members of a new species, Desulfuromonas michiganensis, within the Desulfuromonas cluster of the Geobacteraceae.