Complex Mixture Analysis of Emerging Contaminants Generated from Coal Tar- and Petroleum-Derived Pavement Sealants: Molecular Compositions and Correlations with Toxicity Revealed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

Pavement sealants are of environmental concern because of their complex petroleum-based chemistry and potential toxicity. Specifically, coal tar-derived sealants contain high concentrations of toxic/carcinogenic polycyclic aromatic hydrocarbons (PAHs) that, when weathered, can be transferred into the surrounding environment. Previous studies have demonstrated the effects of coal tar sealants on PAH concentration in nearby waterways and their harmful effects in aquatic ecosystems. Here, we investigate and compare the molecular composition of two different pavement sealants, petroleum asphalt- and coal tar-derived, and their photoproducts, by positive-ion (+) atmospheric pressure photoionization (APPI) and negative-ion (-) electrospray ionization (ESI) coupled with ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry to address species (high-boiling and/or high oxygen content) that lie outside the analytical window of other techniques due to ultra-high molecular complexity. In addition, we evaluate the toxicity of the water-soluble photoproducts by use of Microtox bioassay. The results demonstrate that the coal tar sealant contains higher amounts of PAHs and produces abundant water-soluble compounds, relative to unweathered materials, with a high abundance of PAH-like molecules of high toxicity. By comparison, the asphalt sealant produces fewer toxic water-soluble species, with molecular compositions that are consistent with natural dissolved organic matter. These results capture the mass, chemical diversity, toxicity, and source/photoproduct relationship of these compositionally complex emerging contaminants from the built environment.

Microscopy in addition to chemical analyses and ecotoxicological assays for the environmental hazard assessment of coal tar-polluted soils.

Chemical analysis of soils contaminated with coal tar indicated that most organic compounds, and particularly PAHs, were contained in coarser particles (> 200 µm). Microscopic observations of this fraction, carried out on polished sections, reported the presence of organic particles in addition to mineral particles. Some organic particles had a very low porosity, and their microstructure did not evolve during biotreatment. Alternatively, other organic particles had a large porosity composed of an interconnected pore network that was open to coal tar surface and thus in contact with soil water. Interconnected porosity seemed to increase during biotreatment in relation to a decrease in the amount of organic compounds. The amount of open porosity in contact with soil water was expected to increase the desorption rate of PAHs. Consequently, the environmental hazard could depend on the amount of open porosity in addition to chemical properties of organic particles, such as their concentration in PAHs. Thus, microscopy can be complementary to chemical analysis and ecotoxicological assays to assess the best strategy for remediation but also to follow the advancement of a biotreatment.

Smoldering Remediation of Coal-Tar-Contaminated Soil: Pilot Field Tests of STAR.

Self-sustaining treatment for active remediation (STAR) is an emerging, smoldering-based technology for nonaqueous-phase liquid (NAPL) remediation. This work presents the first in situ field evaluation of STAR. Pilot field tests were performed at 3.0 m (shallow test) and 7.9 m (deep test) below ground surface within distinct lithological units contaminated with coal tar at a former industrial facility. Self-sustained smoldering (i.e., after the in-well ignition heater was terminated) was demonstrated below the water table for the first time. The outward propagation of a NAPL smoldering front was mapped, and the NAPL destruction rate was quantified in real time. A total of 3700 kg of coal tar over 12 days in the shallow test and 860 kg over 11 days in the deep test was destroyed; less than 2% of total mass removed was volatilized. Self-sustaining propagation was relatively uniform radially outward in the deep test, achieving a radius of influence of 3.7 m; strong permeability contrasts and installed barriers influenced the front propagation geometry in the shallow test. Reductions in soil hydrocarbon concentrations of 99.3% and 97.3% were achieved in the shallow and deep tests, respectively. Overall, this provides the first field evaluation of STAR and demonstrates that it is effective in situ and under a variety of conditions and provides the information necessary for designing the full-scale site treatment.

Basics of compounding with tars.

Tar has been used throughout history for numerous purposes; from sealing the hulls of ships to sealing roofs of dwellings and even for medical purposes. Produced by destructive distillation, commonly used tars are prepared from coal and wood. Coal tar, juniper tar, and pine tar are used for various medical purposes as described in the article. Also presented are the various characteristics and uses of each tar, along with commercial products and numerous compounding formulas. Techniques used to compound with tars are also presented.

Separations of petroleum products involving supercritical fluid chromatography.

This paper gives a survey of the most attractive trends and applications of supercritical fluid chromatography in the petroleum industry: simulated distillation, group-type analysis and related applications including the implementation of multidetection in a so-called "hypernated" system, as well as the hyphenation to GC×GC for improved group-type separation, SFC×GC and first promising SFC×SFC results. Some specific technical information related to the use of capillary columns or conventional packed columns in combination with FID (or detectors that require decompression and in some instances splitting of the mobile phase prior detection) is also provided.

Comprehensive profiling of coal tar and crude oil to obtain mass spectra and retention indices for alkylated PAH shows why current methods err.

Investigators use C(1) to C(4) substituted polycyclic aromatic hydrocarbons (PAH) to assess ecological risk and to track fossil fuels and related pollutants in the environment. To quantify these compounds gas chromatography/mass spectrometry (GC/MS) is used. This work demonstrates single ion monitoring (SIM) or extraction (SIE) of full scan data produces inaccurate and imprecise concentration estimates due to incorrect homologue peak assignments. Profiling of coal tar and crude oil by automated sequential GC-GC/MS provided the retention windows and spectral patterns for each homologue to correctly quantify these compounds. Simultaneous pulsed flame photometric (sulfur-specific) detection differentiated PAH from polycyclic aromatic sulfur heterocycles and their alkylated homologues when they eluted within the same retention windows and had common ions. Differences between SIE and spectral deconvolution of GC/MS data based on multiple fragmentation patterns per homologue ranged from a few percent for C(1) compounds to hundreds of percent for the higher alkylated homologues. Findings show current methods produce poor quality data adversely affecting forensic investigations, risk assessments, and weathering studies.

Novel stain-free lecithinized coal tar formulation for psoriasis.

BACKGROUND: Coal tar has been a very popular traditional treatment for various types of psoriasis for over a century. It is the first-line treatment for scalp, hand, and foot psoriasis. However, the application of coal tar on hair invariably causes staining, which results in a high degree of patient non-compliance, especially in patients with non-black hair. Thus, the treatment of scalp psoriasis with a topical coal tar formulation requires that special concern be paid to product esthetics. OBJECTIVE: This study aimed to evaluate the hair-staining characteristics of a novel lecithinized coal tar (LCT) formulation on different types of mammalian hair. METHODS: Samples of hair from different mammals, including human, sheep, rabbit, and goat, were repeatedly exposed to the LCT formulation over 14 days. The color of hair samples treated with LCT was compared with that of untreated control hair samples. RESULTS: The study revealed the distinct non-staining potential of the LCT formulation. CONCLUSIONS: This LCT formulation lacks the propensity to stain hair and thus has excellent potential to be exploited in the treatment of scalp psoriasis.

A vacuum assisted dynamic evaporation interface for two-dimensional normal phase/reverse phase liquid chromatography.

A vacuum assisted dynamic solvent evaporation interface for coupling of two-dimensional normal phase/reverse phase liquid chromatography was developed and evaluated. A normal-phase liquid chromatographic (NPLC) column of a 250mmx4.6mm I.D. 5microm CN phase was used as the first dimension, and a reversed-phase liquid chromatographic (RPLC) column of 250mmx4.6mm I.D. 5micromC(18) phase was used as the second dimension. The eluent from the first dimension flowed into a fraction loop, and the solvent in the eluent was dynamically evaporated and removed by vacuum as it was entering the fraction loop of the interface. The non-evaporable analytes was retained and enriched in about 5-25microL solution within the loop. Up to 1mL/min of mobile phase from the first dimension can be evaporated and removed dynamically by the interface. The mobile phase from the second dimension then entered the loop, and dissolved the concentrated analytes retained inside the loop, and carried them onto the second dimension column for further separation. The operation conditions of the two dimensions were independent from each other, and both dimensions were operated at their optimal chromatographic conditions. We evaluated the interface by controlling the loop temperature in a water bath at normal temperature, and investigated the sample losses by using standard samples with different boiling points. It was found that the sample loss due to evaporation in the interface was negligible for non-volatile samples or for components with boiling point above 340 degrees C. The interface realizes fast solvent removal of mL volume of fraction and concentration of the fraction into tenth of microL volume, and injection of the concentrated fraction on the secondary column. The chromatographic performance of the two-dimensional LC system was enhanced without compromise of separation efficiency and selectivity on each dimension.

Extraction of bitumen, crude oil and its products from tar sand and contaminated sandy soil under effect of ultrasound.

In the present paper, the kinetics of the water extraction of bitumen from tar sand and crude oil or residual fuel oil from model contaminated soils under the effect of ultrasound is studied. The influence of process temperature, ultrasound power, the nature, and properties of the components of heterogeneous mixtures being separated, and the concentration of added alkaline reagents on the rate and degree of oil recovery is investigated. A functional form of the dependencies of separation efficiency on the mean size of solid particles and the temperature of a working medium is found. Optimum concentrations of reagents in the process solution are determined. It is shown that the spent solution of sodium silicate can be multiply used for separation, its reuse even speeding up the yield of oil in the initial period. Taking into account obtained results, a multipurpose pilot plant with a flow-type reactor for ultrasonic extraction of petroleum and its products from contaminated soils was manufactured and tested. During tests, the purification of sandy soil contaminated with residual fuel oil was carried out which verified the results of laboratory studies.

Size-exclusion chromatography of large molecules from coal liquids, petroleum residues, soots, biomass tars and humic substances.

Size-exclusion chromatography (SEC) using 1-methyl-2-pyrrolidinone (NMP) as eluent has been calibrated using various standard polymers and model compounds and applied to the analysis of extracts of coal, petroleum and kerogens, to petroleum vacuum residues, soots, biomass tars and humic substances. Three separate columns of different molecular mass (MM) ranges were used, with detection by UV absorption; an evaporative light scattering detector was used for samples with no UV absorption. Fractionation was useful to separate signal from the less abundant high-mass material, which was normally masked by the strong signal from the more abundant low-mass material in the absence of fractionation. Fractionation methods used to isolate high-mass materials before SEC analysis included planar chromatography, column chromatography and solvent solubility. The apparently large molecules were concentrated into the fractions not soluble in common solvents and were relatively immobile in planar chromatography. All samples and fractions contained some material excluded from the column porosity. Evidence from other techniques suggests that the excluded material is of different structures from that of the resolved material rather than consisting of aggregates of small molecules. We speculate that the excluded material may elute early because the structures of this material are three-dimensional rather than planar or near planar.