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Environmental Science. Processes & Impacts

Casey M Saup, Kenneth H Williams, Lucía Rodríguez-Freire, José M Cerrato, Michael D Johnston, Michael J Wilkins
The Gold King Mine spill in August 2015 released 11 million liters of metal-rich mine waste to the Animas River watershed, an area that has been previously exposed to historical mining activity spanning more than a century. Although adsorption onto fluvial sediments was responsible for rapid immobilization of a significant fraction of the spill-associated metals, patterns of longer-term mobility are poorly constrained. Metals associated with river sediments collected downstream of the Gold King Mine in August 2015 exhibited distinct presence and abundance patterns linked to location and mineralogy...
March 16, 2017: Environmental Science. Processes & Impacts
Nasifu Kerebba, Patrick Ssebugere, Justus Kwetegyeka, Kenneth Arinaitwe, John Wasswa
This study presents the levels and possible sources of selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Napoleon Gulf and Murchison Bay of Lake Victoria. Sediment samples were extracted and cleaned up for PAHs using UNEP, 1992, and EPA method 3630C protocols. The analysis of sample extracts was carried out using a gas chromatograph coupled to a mass spectrometer. Fifteen congeners, mostly the high molecular weight PAHs (HPAHs) (4-6 rings) were detected. Total (∑) concentrations varied from 44...
March 16, 2017: Environmental Science. Processes & Impacts
Tom M Nolte, Ad M J Ragas
Many organic chemicals are ionizable by nature. After use and release into the environment, various fate processes determine their concentrations, and hence exposure to aquatic organisms. In the absence of suitable data, such fate processes can be estimated using Quantitative Structure-Property Relationships (QSPRs). In this review we compiled available QSPRs from the open literature and assessed their applicability towards ionizable organic chemicals. Using quantitative and qualitative criteria we selected the 'best' QSPRs for sorption, (a)biotic degradation, and bioconcentration...
March 15, 2017: Environmental Science. Processes & Impacts
Kathrin Fenner, Paul G Tratnyek
No abstract text is available yet for this article.
March 15, 2017: Environmental Science. Processes & Impacts
Ye Li, Xinran Liu, Min Liu, Xiaofei Li, Qing Wang, Junmin Zhu, Abdul Qadeer
Polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and black carbon (BC) in the estuarine-coastal areas of the East China Sea (ECS) were investigated. The results showed that ∑PAH concentrations ranged from 61 to 355 ng g(-1) with a mean value of 146 ng g(-1). The contents of TOC and BC were in the range of 1.31-7.23 mg g(-1) and 0.52-5.60 mg g(-1), respectively. Data analyses showed that PAH concentrations had a positive linear relationship with TOC and with BC. In addition, the grain size of silts and clays had significant influence on the PAHs of sediments...
March 14, 2017: Environmental Science. Processes & Impacts
Lin Wang, Shengnan Xu, Bo Pan, Yu Yang
Triclosan (TCS), one of the most widely used antimicrobial agents, has been listed among the top 10 contaminants in US rivers. Environmental persistence, endocrine disruption effects, and the antibiotic resistance induction capacity of TCS attract interest in its environmental fate and degradation. Herein, we found that TCS can be anaerobically degraded at pH 9 by a metal-reducing bacterium, Shewanella putrefaciens CN32. The degradation was substantially facilitated by low-concentration (0-15 mg C per L) organic matter (OM) extracted from a peat soil, whereas TCS degradation was inhibited by further increased concentration (15-100 mg C per L) of OM...
March 14, 2017: Environmental Science. Processes & Impacts
H Ge, E Yamazaki, N Yamashita, S Taniyasu, A Ogata, M Furuuchi
Seasonal and local characteristics of perfluorinated alkylated substances (PFASs) were examined using size-segregated particles including an ultrafine range. The examination included sampling and analysis of ambient particles collected at four sites located in different environments in three different countries, Japan (Kanazawa and Okinawa), Hong Kong and India. To minimize the evaporation artefacts derived from PFASs during the sampling, an air sampler that permitted particles smaller than 0.1 μm (PM0.1) to be separated at a moderate pressure drop (<5-15 kPa), was used for all of the air sampling procedures...
March 9, 2017: Environmental Science. Processes & Impacts
Marcella L Card, Vicente Gomez-Alvarez, Wen-Hsiung Lee, David G Lynch, Nerija S Orentas, Mari Titcombe Lee, Edmund M Wong, Robert S Boethling
Chemical property estimation is a key component in many industrial, academic, and regulatory activities, including in the risk assessment associated with the approximately 1000 new chemical pre-manufacture notices the United States Environmental Protection Agency (US EPA) receives annually. The US EPA evaluates fate, exposure and toxicity under the 1976 Toxic Substances Control Act (amended by the 2016 Frank R. Lautenberg Chemical Safety for the 21(st) Century Act), which does not require test data with new chemical applications...
March 9, 2017: Environmental Science. Processes & Impacts
Paul G Tratnyek, Eric J Bylaska, Eric J Weber
Quantitative structure-activity relationships (QSARs) have long been used in the environmental sciences. More recently, molecular modeling and chemoinformatic methods have become widespread. These methods have the potential to expand and accelerate advances in environmental chemistry because they complement observational and experimental data with "in silico" results and analysis. The opportunities and challenges that arise at the intersection between statistical and theoretical in silico methods are most apparent in the context of properties that determine the environmental fate and effects of chemical contaminants (degradation rate constants, partition coefficients, toxicities, etc...
March 6, 2017: Environmental Science. Processes & Impacts
Hassan Waseem, Maggie R Williams, Tiffany Stedtfeld, Benli Chai, Robert D Stedtfeld, James R Cole, James M Tiedje, Syed A Hashsham
Virulence factor activity relationships (VFARs) - a concept loosely based on quantitative structure-activity relationships (QSARs) for chemicals was proposed as a predictive tool for ranking risks due to microorganisms relevant to water safety. A rapid increase in sequencing capabilities and bioinformatics tools has significantly increased the potential for VFAR-based analyses. This review summarizes more than 20 bioinformatics databases and tools, developed over the last decade, along with their virulence and antimicrobial resistance prediction capabilities...
March 6, 2017: Environmental Science. Processes & Impacts
Xiang Luo, Xianhai Yang, Xianliang Qiao, Ya Wang, Jingwen Chen, Xiaoxuan Wei, Willie J G M Peijnenburg
Reaction with hydroxyl radicals (˙OH) is an important removal pathway for organic pollutants in the aquatic environment. The aqueous reaction rate constant (kOH) is therefore an important parameter for fate assessment of aquatic pollutants. Since experimental determination fails to meet the requirement of being able to efficiently handle numerous organic chemicals at limited cost and within a relatively short period of time, in silico methods such as quantitative structure-activity relationship (QSAR) models are needed to predict kOH...
March 6, 2017: Environmental Science. Processes & Impacts
Daniel R S Middleton, Michael J Watts, Darren J Beriro, Elliott M Hamilton, Giovanni S Leonardi, Tony Fletcher, Rebecca M Close, David A Polya
Exposure to arsenic (As) via residential soil and dust is a global concern, in regions affected by mining or with elevated concentrations present in underlying geology. Cornwall in south west England is one such area. Residential soil (n = 127) and household dust (n = 99) samples were collected from across Cornwall as part of a wider study assessing exposure to environmental As. Samples were analysed for total As (soil and dust samples) and human ingestion bioaccessible As (soil samples from properties with home-grown produce)...
March 1, 2017: Environmental Science. Processes & Impacts
Elena Appiani, Rachele Ossola, Douglas E Latch, Paul R Erickson, Kristopher McNeill
The rate constant for the reaction between furfuryl alcohol (FFA) and singlet oxygen ((1)O2) in aqueous solution was measured as a function of temperature, pH and salt content employing both steady-state photolysis (β value determination) and time-resolved singlet oxygen phosphorescence methods. The latter provided more precise and reproducible data. The reaction rate constant, krxn,FFA, had a relatively small temperature dependence, no pH dependence and showed a small increase in the presence of high salt concentrations (+19% with 1 M NaCl)...
February 28, 2017: Environmental Science. Processes & Impacts
Mark T D Cronin
The current state of the art of (Quantitative) Structure-Activity Relationships ((Q)SARs) to predict environmental toxicity is assessed along with recommendations to develop these models further. The acute toxicity of compounds acting by the non-polar narcotic mechanism of action can be well predicted, however other approaches, including read-across, may be required for compounds acting by specific mechanisms of action. The chronic toxicity of compounds to environmental species is more difficult to predict from (Q)SARs, with robust data sets and more mechanistic information required...
February 28, 2017: Environmental Science. Processes & Impacts
Manuel Krapf, Lisa Künzi, Sandrine Allenbach, Emily A Bruns, Ilaria Gavarini, Imad El-Haddad, Jay G Slowik, André S H Prévôt, Luka Drinovec, Griša Močnik, Lutz Dümbgen, Matthias Salathe, Nathalie Baumlin, Constantinos Sioutas, Urs Baltensperger, Josef Dommen, Marianne Geiser
Residential wood burning is a major source of poorly characterized, deleterious particulate matter, whose composition and toxicity may vary with wood type, burning condition and photochemical age. The causative link between ambient wood particle constituents and observed adverse health effects is currently lacking. Here we investigate the relationship between chemical properties of primary and atmospherically aged wood combustion particles and acute toxicity in human airway epithelial cells. Emissions from a log wood burner were diluted and injected into a smog chamber for photochemical aging...
February 27, 2017: Environmental Science. Processes & Impacts
Reza Aalizadeh, Peter C von der Ohe, Nikolaos S Thomaidis
According to the European REACH Directive, the acute toxicity towards Daphnia magna should be assessed for any industrial chemical with a market volume of more than 1 t/a. Therefore, it is highly recommended to determine the toxicity at a certain confidence level, either experimentally or by applying reliable prediction models. To this end, a large dataset was compiled, with the experimental acute toxicity values (pLC50) of 1353 compounds in Daphnia magna after 48 h of exposure. A novel quantitative structure-toxicity relationship (QSTR) model was developed, using Ant Colony Optimization (ACO) to select the most relevant set of molecular descriptors, and Support Vector Machine (SVM) to correlate the selected descriptors with the toxicity data...
February 24, 2017: Environmental Science. Processes & Impacts
Zhe Li, Sarit L Kaserzon, Merle M Plassmann, Anna Sobek, María José Gómez Ramos, Michael Radke
Many transformation products (TPs) from organic micropollutants are not included in routine environmental monitoring programs due to limited knowledge of their occurrence and fate. An efficient method to identify and prioritize critical compounds in terms of environmental relevance is needed. In this study, we applied a strategic screening approach based on a case-control concept to identify TPs formed along wastewater-impacted rivers. Time-integrated samples were collected over one week at both ends of a river stretch downstream of a wastewater treatment plant (WWTP) outfall and were analyzed by ultrahigh performance liquid chromatography interfaced with quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS/MS)...
February 24, 2017: Environmental Science. Processes & Impacts
Sangavi Pari, Inger A Wang, Haizhou Liu, Bryan M Wong
Advanced oxidation processes that utilize highly oxidative radicals are widely used in water reuse treatment. In recent years, the application of sulfate radical (SO4˙(-)) as a promising oxidant for water treatment has gained increasing attention. To understand the efficiency of SO4˙(-) in the degradation of organic contaminants in wastewater effluent, it is important to be able to predict the reaction kinetics of various SO4˙(-)-driven oxidation reactions. In this study, we utilize density functional theory (DFT) and high-level wavefunction-based methods (including computationally-intensive coupled cluster methods), to explore the activation energies of SO4˙(-)-driven oxidation reactions on a series of benzene-derived contaminants...
February 23, 2017: Environmental Science. Processes & Impacts
Ania S Pavitt, Eric J Bylaska, Paul G Tratnyek
Phenols and anilines have been studied extensively as reductants of environmental oxidants (such as manganese dioxide) and as reductates (e.g., model contaminants) that are transformed by environmental oxidants (ozone, triple organic matter, etc.). The thermodynamics and kinetics of these reactions have been interpreted using oxidation potentials for substituted phenols and anilines, often using a legacy experimental dataset that is of uncertain quality. Although there are many alternative oxidation potential data, there has been little systematic analysis of the relevance, reliability, and consistency of the data obtained by different methods...
February 23, 2017: Environmental Science. Processes & Impacts
Diogo A R S Latino, Jörg Wicker, Martin Gütlein, Emanuel Schmid, Stefan Kramer, Kathrin Fenner
Developing models for the prediction of microbial biotransformation pathways and half-lives of trace organic contaminants in different environments requires as training data easily accessible and sufficiently large collections of respective biotransformation data that are annotated with metadata on study conditions. Here, we present the Eawag-Soil package, a public database that has been developed to contain all freely accessible regulatory data on pesticide degradation in laboratory soil simulation studies for pesticides registered in the EU (282 degradation pathways, 1535 reactions, 1619 compounds and 4716 biotransformation half-life values with corresponding metadata on study conditions)...
February 23, 2017: Environmental Science. Processes & Impacts
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