TY  - JOUR
AB  - Trichloroethylene (TCE) is a carcinogenic organic chemical impacting water resources worldwide. Its breakdown by reductive vs oxidative degradation involves different types of chemical bonds. Hence, if distinct isotope effects are reflected in dual element (carbon and chlorine) isotope values, such trends could help distinguishing both processes in the environment. This work explored dual element isotope trends associated with TCE oxidation by two pure bacterial cultures: Pseudomonas putida F1 and Methylosinus trichosporium OB3b, where the latter expresses either soluble methane-monooxygenase (sMMO) or particulate methane-monooxygenase (pMMO). Carbon and chlorine isotope enrichment factors of TCE (ϵ13C = -11.5, -2.4, and -4.2‰ ϵ37Cl = 0.3, -1.3, and -2.4‰, respectively) differed strongly between the strains. The dual element isotope trend for strain F1 (ϵ13C/ϵ37Cl = -38) reflected, as expected, primary carbon and negligible chlorine isotope effects, whereas unexpectedly large chlorine isotope effects became apparent in the trend obtained with strain OB3b (ϵ13C/ϵ37Cl = +1.7 for sMMO and pMMO). Therefore, although dual element isotope analysis partly reflects predicted differences in oxidative vs reductive (ϵ13C/ϵ37Cl = 3.4-5.7) degradation, the unexpected OB3b fractionation data may challenge field interpretation.
AU  - Gafni, A.*
AU  - Lihl, C.
AU  - Gelman, F.*
AU  - Elsner, M.
AU  - Bernstein, A.*
C1  - 53840
C2  - 45081
SP  - 202-208
TI  - δ13C and δ37Cl isotope fractionation to characterize aerobic vs. anaerobic degradation of trichloroethylene.
JO  - Environ. Sci. Technol. Lett.
VL  - 5
IS  - 4
PY  - 2018
SN  - 2328-8930
ER  - 

TY  - JOUR
AB  - A proton-transfer-reaction time-of-flight mass spectrometer combined with the novel CHARON (“chemical analysis of aerosol online”) aerosol inlet was used for characterization of submicrometer particulate organic matter in ship engine exhaust. Particles were sampled from diluted and cooled exhaust of a marine test bench engine that was operated on residual heavy fuel oil (HFO) and low-sulfur distillate marine gas oil (MGO), respectively. In both fuel operation modes, exhaust particle mass spectra were dominated by polycycloalkanes in the C20-to-C39 range, which are typical main constituents of lubricating oils. Exhaust particle mass spectra were closely reproduced when the engine’s lubricant oil was directly measured in aerosolized form. We report emission profiles of lubricant oil hydrocarbons as a function of their volatility and as a function of their carbon atom number. Total emissions of lubricant oil amounted to 183 and 74 mg kW-1 h-1 for HFO and MGO combustion, respectively. These values resemble typical oil loss rates of marine four-stroke trunk piston engines in which most of the lubricant is known to be lost through the combustion chamber and the tailpipe. We conclude that marine trunk piston engines are generally prone to high emissions of particles mainly composed of unburned lubricating oil.
AU  - Eichler, P.*
AU  - Müller, M.*
AU  - Rohmann, C.*
AU  - Stengel, B.*
AU  - Orasche, J.
AU  - Zimmermann, R.
AU  - Wisthaler, A.*
C1  - 50550
C2  - 42574
CY  - Washington
SP  - 54-58
TI  - Lubricating oil as a major constituent of ship exhaust particles.
JO  - Environ. Sci. Technol. Lett.
VL  - 4
IS  - 2
PB  - Amer Chemical Soc
PY  - 2017
SN  - 2328-8930
ER  -