Natural Attenuation of Trichloroethylene in Rhizosphere Soils at the Savannah River Site

Extensive trichloroethylene (TCE) groundwater contamination has resulted from discharges to a former seepage basin in the A/M Area at the Department of Energy's Savannah River Site. The direction of groundwater flow has been determined and a seep line where the contaminated groundwater is estimated to emerge as surface water has been identified in a region of the Southern Sector of the A/M Area. This study was undertaken to estimate the potential of four rhizosphere soils along the seep line to naturally attenuate TCE. Microcosms were setup to evaluate both biotic and abiotic attenuation of TCE. Results demonstrated that sorption to soil was the dominant mechanism during the first week of incubation, with as much as 90% of the TCE removed from the aqueous phase. Linear partitioning coefficients (K_d) ranged from 0.83 to 7.4?mL/g, while organic carbon partition coefficients (K_oc) ranged from 72 to 180?mL/gC. Diffu-sional losses from the microcosms appeared to be a dominant fate mechanism during the remainder of the experiment, as indicated by results from the water controls. A limited amount of TCE biodegradation was observed, and attempts to stimulate TCE biodegradation by either methanotrophic or methanogenic activity through amendments with methane, oxygen, and methanol were unsuccessful. The appearance of cis-1,2-dichloroethylene (c-DCE), and trans-1,2-dichloroethylene (t-DCE) confirmed the potential for anaerobic reductive dechlorination. However, these daughter products represented less than 5% of the initial TCE added. The sorption results indicate that natural attenuation may represent a viable remediation option for the TCE plume as it passes through the rhizosphere.     

Enhanced uptake of Cd by biofilm forming Cd resistant plant growth promoting bacteria bioaugmented to the rhizosphere of Vetiveria zizanioides

Abstract

Heavy metals are the major cause of pollution and cadmium is one among the highly toxic metals discharged into the environment from various industries. The current study was focused on the bioremoval of cadmium by phyto and rhizoremediation approach using Vetiveria zizanioides. The bacterial strains were isolated from wetland paddy rhizosphere soil and the isolate VITJAN13 was found to be a biofilm forming Cd resistant plant growth promoting rhizobacteria (PGPR). The 16S rRNA gene sequencing revealed VITJAN13 to be the closest neighbor of Aeromonas sp. and was submitted to Genbank with the accession number KX770741. Further, pot culture studies indicated that the treatments bioaugmented with VITJAN13 increased the root length and shoot height by 21.4 and 17.36%, respectively as compared to the non-augmented plants. Hence, bioaugmentation of Aeromonas sp. in the rhizosphere of Vetiveria zizanioides enhanced the uptake of cadmium by 67.7% in the soil treated with 15?mg/kg of Cd to that of the phytoremediation setup.     

Petroleum Degradation,Biosurfactant and Laccase Production by Fusarium neocosmosporiellum RH-10: A Microcosm Study

The aim of this study was to evaluate the potential of crude oil removal by fungal strains isolated from Arak refinery. The results showed that the RH10 strain is a potent strain as a surfactant producer and degrader of petrochemical hydrocarbons. The strain was identified as a Fusarium neocosmosporiellum and could degrade 58% of hydrocarbons in the minimal medium and reduce the surface tension from 45 to 26.5 mN m^?1. Moreover, residual crude oil analysis with Fourier transform infrared spectrophotometry showed that this strain was able to degrade 50% of aliphatic compounds. To investigate the mechanism of degradation, oxidase enzymes were assayed and it was found that F. neocosmosporiellum can produce 1.94 U L^?1 of laccase in 10 g L^?1 crude oil. Carbon, nitrogen, phosphorus and soil pattern optimization in a microcosm study showed that this strain removed 44% and 27% of the crude oil from contaminated soil in 1% and 5% crude oil concentrations, respectively. Under optimum condition, 9.66 g kg^?1 crude oil was removed by F. neocosmosporiellum when the initial oil concentration was 50 g kg^?1, at the end of 150 days microcosm experiment. The results demonstrated the promising potential of fungi strain for cleaning of contaminated soil.     

A Review of Processes Responsible for Metal Removal in Wetlands Treating Contaminated Mine Drainage

Many reports have documented wetlands removing a wide variety of contaminants in mine drainage, including aluminum, arsenic, cadmium, cobalt, copper, cyanide, iron, lead, manganese, nickel, selenium, uranium, and zinc. This article reviews biogeochemical processes responsible for their ability to transform and retain metals into insoluble forms. Shallow depth and large inputs of organic matter are key characteristics of wetlands that promote chemical and biological processes effecting metal removal. Aquatic macrophytes play an essential role in creating and maintaining this environment, but their uptake of metals usually accounts for a minor proportion of the total mass removed. Sorption onto organic matter is important in metal removal, particularly for copper, nickel, and uranium. Aluminum, iron, and manganese are often removed by hydrolysis, with the resulting acidification of water buffered by alkalinity produced in wetland sediments by anaerobic bacteria. Bacterial sulfate reduction accounts for much of this alkalinity. It can also contribute significantly to metal removal by formation of insoluble sulfides. Other important processes include the formation of insoluble carbonates, reduction to nonmobile forms, and adsorption onto iron oxides and hydroxides. Examples from field studies are presented throughout the review to illustrate these processes.     

从第五届国际湿地会议看湿地保护与研究趋势

从第五届国际湿地会议看湿地保护与研究趋势王仁卿刘纯慧晁敏（山东大学生命科学院生物系,济南２５０１００）ＷｅｔｌａｎｄＣｏｎｓｅｒｖａｔｉｏｎａｎｄＡｄｖａｎｃｅｓＤｅｒｉｖｅｄｆｒｏｍｔｈｅｆｉｆｔｈＩｎｔｅｒｎａｔｉｏｎａｌＷｅｔｌａｎｄｓＣｏｎｆ...     

A Novel,Open Access Method to Assess Sleep Duration Using a Wrist-Worn Accelerometer

Wrist-worn accelerometers are increasingly being used for the assessment of physical activity in population studies, but little is known about their value for sleep assessment. We developed a novel method of assessing sleep duration using data from 4,094 Whitehall II Study (United Kingdom, 2012–2013) participants aged 60–83 who wore the accelerometer for 9 consecutive days, filled in a sleep log and reported sleep duration via questionnaire. Our sleep detection algorithm defined (nocturnal) sleep as a period of sustained inactivity, itself detected as the absence of change in arm angle greater than 5 degrees for 5 minutes or more, during a period recorded as sleep by the participant in their sleep log. The resulting estimate of sleep duration had a moderate (but similar to previous findings) agreement with questionnaire based measures for time in bed, defined as the difference between sleep onset and waking time (kappa = 0.32, 95%CI:0.29,0.34) and total sleep duration (kappa = 0.39, 0.36,0.42). This estimate was lower for time in bed for women, depressed participants, those reporting more insomnia symptoms, and on weekend days. No such group differences were found for total sleep duration. Our algorithm was validated against data from a polysomnography study on 28 persons which found a longer time window and lower angle threshold to have better sensitivity to wakefulness, while the reverse was true for sensitivity to sleep. The novelty of our method is the use of a generic algorithm that will allow comparison between studies rather than a “count” based, device specific method.     

Characterization of Neutrophilic Fe(II)-Oxidizing Bacteria Isolated from the Rhizosphere of Wetland Plants and Description of Ferritrophicum radicicola gen. nov. sp. nov., and Sideroxydans paludicola sp. nov.

Iron deposits (Fe plaque) on wetland plant roots contain abundant microbial populations, including Fe(II)-oxidizing bacteria (FeOB) that have not been cultured previously. In this study, 4 strains of Fe plaque-associated FeOB were isolated from 4 species of wetland plants. All 4 isolates grew in tight association with Fe-oxides, but did not form any identifiable Fe-oxide structures. All strains were obligate lithotrophic Fe(II)-oxidizers that were microaerobic, and were unable to use other inorganic or organic energy sources. One strain, BrT, was shown to fix ¹⁴ CO ₂ at a rate consistent with its requirement for total cell carbon. The doubling times for the strains varied between 9.5 and 15.8 hours. The fatty acid methyl ester (FAME) profiles of 2 strains, BrT and CCJ, revealed that 16:0, 15:1 isoG, and 14:0 were dominant fatty acids. Phylogenetic analysis of the 16S rRNA gene indicated that all the strains were Betaproteobacteria. Two of the strains, BrT and Br-1 belong to a new species, Sideroxydans paludicola; a third strain, LD-1, is related to Sideroxydans lithotrophicus, a recently described species of FeOB. The fourth isolate, Ferritrophicum radicicola, represented a new genus in a new order of Betaproteobacteria, the Ferritrophicales. There are no other cultured isolates in this order. A small subunit rRNA gene-based, cultivation-independent analysis of Typha latifolia collected from a wetland revealed terminal restriction fragment profiles (tRFLP) consistent with the presence of these bacteria in the rhizosphere. These novel organisms likely play an important role in Fe(II) oxidation kinetics and Fe cycling within many terrestrial and freshwater environments.     

Effects of Indole-3-Acetic Acid (IAA), a Plant Hormone,on the Ryegrass Yield and the Removal of Fluoranthene from Soil

A soil culture experiment was conducted to determine whether a plant hormone, indole-3-acetic acid (IAA), could influence fluoranthene (Flu) removal from soil. Four treatments were utilized: (i) unplanted soil (CK), (ii) soil planted with ryegrass (P), (iii) soil planted with ryegrass and treated with 0.24 mg kg^?1 IAA (P+0.24), (iv) soil planted with ryegrass and treated with 2.4 mg kg^?1 IAA (P+2.4). The Flu initial concentration was 200 mg kg^?1. After 3 months, the percentage of Flu removal and plant root biomass were significantly increased under the P+2.4 and the removal rate was 35.68%. The total Flu content in plants was higher than that in the other treatments. The Flu concentration was significantly increased in the shoots, but not significantly altered in the roots. The highest translocation factor was observed in the P+2.4. Increase in number of bacteria, actinomycetes and fungi were observed in the planted treatments, and the amount of fungi was significantly increased in P+2.4. Flu removal was related to the Flu in ryegrass, and was insignificantly correlated with the stimulation of soil microflora, which suggesting that IAA may work mainly on improving plant growth, the Flu uptake, and eventually leading to enhanced remediation of Flu polluted soil.     

发现微生物药物的新途径:从基因到新化合物

本文介绍一种基于基因组扫描(鸟枪法)和生物信息学相结合的寻找微生物新化合物的平台.基因组扫描发现新的合成基因,通过对新的次生代谢产物合成途径基因的分析,预测化合物的结构、物理化学性质参数,指导该化合物的分离与纯化.     

Bioremediation and Biorestoration of a Crube Oil-Contaminated Freshwater Wetland on the St.Lawrence River

Biostimulation by nutrient enrichment and phytoremediation were studied for the restoration of an acutely stressed freshwater wetland experimentally exposed to crude oil. The research was carried out along the shores of the St. Lawarence River at Ste. Croix, Quebec, Canada. The research determined the effectiveness of fertilizer addition in enhancing the biodegradation rates of residual oil. It further examined the rate at which the stressed ecosystem recovered with and without the addition of inorganic fertilizers and the role of nutrients in enhancing wetland restoration in the absence of healthy wetland plants. Chemical analysis of integrated sediment core samples to the depth of oil penetration within the experimental plots indicated that addition of inorganic nutrients did not enhance the disappearance of alkanes or PAHs. In surface samples, however, hydrocarbon disappearance rates were higher when the metabolic activity of wetland plants was suppressed by the removal of emergent plant growth. These results suggest that oxygen limitation plays a major role in preventing rapid biodegradation of hydrocarbons in anoxic wetland sediment.     

Using the RESRAD Code to Assess Human Exposure Risk to 226Ra, 232Th,and 40K in Soil

This article evaluates the health risk raised by exposure to naturally occurring radionuclides in soil around Khak-Sefid, Ramsar, Iran, which is an area of high natural background radiation. A high purity germanium detector was used to determine levels of radionuclides in soil samples and the cancer morbidity risk for a hypothetical resident farmer was evaluated using the RESidual RADioactivity (RESRAD) code. The average activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 13,201 ± 391, 27.9 ± 2.4, and 415.5 ± 16 Bq/kg, respectively. The maximum assessed cancer morbidity risks were calculated from external and internal exposure pathways as 4.73 × 10^?2 and 3.40 × 10^?2 for ²²⁶Ra, 1.41 × 10^?4 and 7.88 × 10^?5 for ²³²Th, and 1.3 × 10^?4 and 4.233 × 10^?4 for ⁴⁰K. The RESRAD calculations also showed total cancer morbidity risks from external gamma and plant ingestion pathways were more important than from other exposure pathways. A sensitivity analysis was also performed to determine the input parameter values in the risk assessment process. In general, due to the high calculated risk of ²²⁶Ra compared with ²³²Th and ⁴⁰K it can be the major source of concern for human heath in the study area.     

PRISM: A Novel Research Tool to Assess the Prevalence of Pseudobulbar Affect Symptoms across Neurological Conditions

Background

Pseudobulbar affect (PBA) is a neurological condition characterized by involuntary, sudden, and frequent episodes of laughing and/or crying, which can be socially disabling. Although PBA occurs secondary to many neurological conditions, with an estimated United States (US) prevalence of up to 2 million persons, it is thought to be under-recognized and undertreated. The PBA Registry Series (PRISM) was established to provide additional PBA symptom prevalence data in a large, representative US sample of patients with neurological conditions known to be associated with PBA.

Methods

Participating clinicians were asked to enroll ≥20 consenting patients with any of 6 conditions: Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson’s disease (PD), stroke, or traumatic brain injury (TBI). Patients (or their caregivers) completed the Center for Neurologic Study−Lability Scale (CNS-LS) and an 11-point scale measuring impact of the neurological condition on the patient’s quality of life (QOL). Presence of PBA symptoms was defined as a CNS−LS score ≥13. Demographic data and current use of antidepressant or antipsychotic medications were also recorded.

Results

PRISM enrolled 5290 patients. More than one third of patients (n = 1944; 36.7%) had a CNS-LS score ≥13, suggesting PBA symptoms. The mean (SD) score measuring impact of neurological condition on QOL was significantly higher (worse) in patients with CNS-LS ≥13 vs <13 (6.7 [2.5] vs. 4.7 [3.1], respectively; P<0.0001 two-sample t-test). A greater percentage of patients with CNS−LS ≥13 versus <13 were using antidepressant/antipsychotic medications (53.0% vs 35.4%, respectively; P<0.0001, chi-square test).

Conclusions

Data from PRISM, the largest clinic-based study to assess PBA symptom prevalence, showed that PBA symptoms were common among patients with diverse neurological conditions. Higher CNS−LS scores were associated with impaired QOL and greater use of antipsychotic/antidepressant medications. These data underscore a need for greater awareness, recognition, and diagnosis of PBA.     

A Novel Algorithm for Movement Artifact Removal in ECG Signals Acquired from Wearable Systems Applied to Horses

This study reports on a novel method to detect and reduce the contribution of movement artifact (MA) in electrocardiogram (ECG) recordings gathered from horses in free movement conditions. We propose a model that integrates cardiovascular and movement information to estimate the MA contribution. Specifically, ECG and physical activity are continuously acquired from seven horses through a wearable system. Such a system employs completely integrated textile electrodes to monitor ECG and is also equipped with a triaxial accelerometer for movement monitoring. In the literature, the most used technique to remove movement artifacts, when noise bandwidth overlaps the primary source bandwidth, is the adaptive filter. In this study we propose a new algorithm, hereinafter called Stationary Wavelet Movement Artifact Reduction (SWMAR), where the Stationary Wavelet Transform (SWT) decomposition algorithm is employed to identify and remove movement artifacts from ECG signals in horses. A comparative analysis with the Normalized Least Mean Square Adaptive Filter technique (NLMSAF) is performed as well. Results achieved on seven hours of recordings showed a reduction greater than 40% of MA percentage (between before- and after- the application of the proposed algorithm). Moreover, the comparative analysis with the NLMSAF, applied to the same ECG recordings, showed a greater reduction of MA percentage in favour of SWMAR with a statistical significant difference (p–value < 0.0.5).     

Determining discharges from the Table Mountain Group (TMG) aquifer to wetlands in the Southern Cape, South Africa

The focus of this study was to determine whether coastal wetlands in lowland settings could be dependent on groundwater from the deep circulating confined Table Mountain Group (TMG) aquifer. Groundwater interactions with wetlands are normally perceived to be limited to primary aquifers. A comparative study was done between two endorheic coastal wetlands in the southern Cape. Earlier reports stated that these groundwater dependent wetlands were fed by discharges from the fixed dunes surrounding them. On the basis of a three-dimensional electrical conductivity (EC) interpolation for Groenvlei, a hydrological link between the TMG aquifer and Groenvlei and Van Kervelsvlei was investigated by measuring water level and quality of groundwater and surface water. Water quality parameters used were EC, pH, Na⁺, Fe²⁺ and Cl⁻. The results from this, and an accompanying study, on the basis of water quality and plant nutrient cycling assessments, indicated direct groundwater discharges from the TMG to at least Van Kervelsvlei, with Groenvlei receiving secondary discharges from the TMG via Van Kervelslvlei. These findings significantly affect the current knowledge on which water balance models are based for the determination of groundwater availability for the area. Handling editor: D. Hamilton The first author did the research as part of his PhD in the Department of Earth Sciences of the University of the Western Cape, Bellville, South Africa. Funding is quoted under acknowledgements.     

A Site-Specific Approach for the Evaluation of Natural Attenuation at Metals-Impacted Sites

Consideration of monitored natural attenuation (MNA) as a remedy component for metals-contaminated sites can be achieved using a site-specific screening approach, followed by application of one or a series of sequential extraction measurements. Hazardous waste sites contaminated with metals can be screened for the implementation of monitored natural attenuation on the basis of contaminant-specific soil chemical characteristics (i.e., K_d's, solubilities, and nonexchangeable sorbed fraction). Field cases are used to demonstrate the screening approach and to outline the primary considerations involved in accurately applying sequential extraction procedures to support the of MNA for site remediation. The results of these case studies provide strong evidence that site-specific screening and the use of sequential extraction procedures are effective methods for evaluating natural attenuation for metals impacted sites.     

Temporal hydrochemical and microbial variations in microcosm experiments from sites contaminated with chloromethanes under biostimulation with lactic acid

The aim of this research was to identify the sequence of degradation processes that leads to the selective enrichment of microorganisms involved in the degradation of carbon tetrachloride and chloroform under conditions of natural attenuation and lactic acid biostimulation. To this end, a comparative study using microcosm experiments was conducted to analyze these two scenarios. The authors used groundwater and sediment collected from a field site located at a petrochemical complex to create the microcosms. Chemical, compound-specific isotope and microbial analyses were performed. A significant finding of this work was the abiotic degradation of carbon tetrachloride. Another result was the identification of biotic reductive dechlorination of chloroform by a bacterium of the Clostridiales order. This study showed that biostimulation with lactic acid produced faster degradation rates of carbon tetrachloride and chloroform. Lactic acid acted as an electron donor and promoted a decrease in the concentration of other electron acceptors such as nitrate and sulfate, which competed with chloromethanes. Thus, biostimulation could be an efficient remediation strategy for sites contaminated with chloromethanes, especially when a site's complex pollution history results in chemical background concentrations that are high in compounds that could potentially reduce natural attenuation.     

Development of a PCR method for the detection and quantification of benzoyl-CoA reductase genes and its application to monitored natural attenuation

Benzoyl coenzyme A reductase (BCR) catalyzes dearomatization of benzoyl coenzyme A (benzoyl-CoA), which is the central step in the anaerobic degradative pathways for a variety of aromatic compounds. This study developed a PCR method for the detection and quantification of BCR genes in bacterial strains and environmental samples. PCR primers were designed by aligning known BCR genes in Thauera, Azoarcus and Rhodopseudomonas species, and their utility was assessed by amplifying BCR fragments from aromatic-hydrocarbon degrading anaerobes and other bacteria. BCR fragments with the expected sizes were obtained from denitrifying and phototrophic aromatics degraders. The positive signals were also obtained from Geobacter metallireducens and xylene-degrading sulfate-reducing bacterium (strain mXyS1) but not from other aromatics-degrading sulfate-reducing bacteria and aerobic bacteria. When the PCR was used for analyzing a natural attenuation (NA) site, the positive signal was obtained only from gasoline-contaminated groundwater; sequence analysis of these amplicons revealed that most of them exhibited substantial similarities to the known BCRs. Quantitative competitive PCR analysis estimated BCR-gene copies to account for 10–40% of bacterial 16S rRNA gene copies in the contaminated groundwater, indicating that bacteria possessing BCR genes were highly enriched in the contaminated groundwater. In microcosm bioremediation tests using the contaminated groundwater, the copy number of BCR gene was approximately 10-fold increased in the course of aromatics degradation under denitrifying conditions but not under sulfidogenic conditions. These results suggest the utility of the PCR method for assessing the potential of denitrifying bacteria for aromatic-compound degradation in groundwater.     

Structure of Cyl-2, a Novel Cyclotetrapeptide from Cylindrocladium scoparium

Fermentative production of pyruvic acid by yeasts was studied using extracts from citrus natsudaidai peel as a carbon source. Many yeasts showed good growth. Of these yeasts, Debaryomyces coudertii IFO 1381 produced pyruvic acid at high yield. Pretreatment of the peel extract with Amberlite IR-120B (Na⁺) led to increased production of pyruvic acid. Under optimum conditions, the accumulation of pyruvic acid reached a maximum of 970 mg/100ml at 48 hr-fermentation. The pyruvic acid from the fermentation broth was identified with lactic acid dehydrogenase and by comparisons of properties of its 2,4-dinitrophenylhydrazone with those of authentic pyruvic acid in paper chromatography, IR spectrometry and elemental analysis.