Changes in Temperature Alter the Toxicity of Polycyclic Aromatic Compounds to American Lobster (Homarus americanus) Larvae

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Changes in Temperature Alter the Toxicity of Polycyclic Aromatic Compounds to American Lobster (Homarus americanus) Larvae

Temperature alters the toxicity of polycyclic aromatic compounds to Stage I American lobster larvae, and these temperature-based differences in toxicity are important data inputs for oil spill effects models.


Abstract

Polycyclic aromatic compounds (PACs) present in the water column are considered to be one of the primary contaminant groups contributing to the toxicity of a crude oil spill. Because crude oil is a complex mixture composed of thousands of different compounds, oil spill models rely on quantitative structure–activity relationships like the target lipid model to predict the effects of crude oil exposure on aquatic life. These models rely on input provided by single species toxicity studies, which remain insufficient. Although the toxicity of select PACs has been well studied, there is little data available for many, including transformation products such as oxidized hydrocarbons. In addition, the effect of environmental influencing factors such as temperature on PAC toxicity is a wide data gap. In response to these needs, in the present study, Stage I lobster larvae were exposed to six different understudied PACs (naphthalene, fluorenone, methylnaphthalene, phenanthrene, dibenzothiophene, and fluoranthene) at three different relevant temperatures (10, 15, and 20 °C) all within the biological norms for the species during summer when larval releases occur. Lobster larvae were assessed for immobilization as a sublethal effect and mortality following 3, 6, 12, 24, and 48 h of exposure. Higher temperatures increased the rate at which immobilization and mortality were observed for each of the compounds tested and also altered the predicted critical target lipid body burden, incipient median lethal concentration, and elimination rate. Our results demonstrate that temperature has an important influence on PAC toxicity for this species and provides critical data for oil spill modeling. More studies are needed so oil spill models can be appropriately calibrated and to improve their predictive ability. Environ Toxicol Chem 2023;00:1–11. © 2023 SETAC

Quantification of CO and Further CO2 Reduction Products by On‐line Mass Spectrometry

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Quantification of CO and Further CO2 Reduction Products by On-line Mass Spectrometry

Careful adjustment of ionization energy enables the specific quantification of carbon monoxide in gas mixtures containing CO2 and N2, both of which otherwise would cause interferences. This technique is applied for the analysis of CO2RR products, both for headspace gas analysis as well as in real-time analysis, also known as differential electrochemical mass spectrometry.


Abstract

The reduction of CO2 in water can yield a variety of volatile products mixed with the starting material and often dinitrogen as an inert gas. While mass spectrometry is ideally suited to the quantitative analysis of gases in low concentrations, the simultaneous detection is usually performed with a preliminary chromatographic separation. In its absence, the mass spectrometric signal at m/z=28 can be due to CO, CO2, and N2. Here, we demonstrate that ionizing the mixture of reaction products under 16 eV results in the selective detection of CO at m/z=28, at the complete exclusion of CO2 and N2. This method is applicable to headspace analysis after a bulk electrolysis and delivers product compositions as they depend on catalyst and applied potential. Furthermore, its immediate nature also enables the experimentalist to perform, in real time, a direct monitoring of the reaction products generated during cyclic voltammetry.