Description: Kanechlor-300, -400, -500 and -600, Phenoclor DP-3, -4, -5 and -6 and Sovol mixtures were analyzed for their chlorobiphenyl (CB) composition using high-resolution one-dimensional and multidimensional gas chromatography-electron capture detection (MDGC-ECD) techniques. The congener patterns of tested Kanechlor and Phenoclor mixtures resembled Aroclor 1016, 1242, 1254 and 1260. However, differences in the percentage contribution of minor constituents were noticed among these mixtures, which could be due to variations in the boiling-point fractionation of these commercial products. CB pattern of Sovol was different from the rest of the mixtures tested. It showed a composition in between ca. 30%, 40%, 50% and 60% overall chlorine levels. MDGC-ECD study showed the presence of hitherto unnoticed non-CB compounds coeluting with CBs in some commercial PCBs. The use of these mixtures as quantitation standards should be considered with caution. CB patterns of Sovol and a water extract of the Gulf of Finland matched closely, indicating a point source contamination to these waters.

Description: Accurate congener-specific determination of chlorobiphenyl congeners (all 209 congeners) is finally possible with the use of multidimensional gas chromatography-electron-capture detection techniques. The effectiveness of this technique for environmental analyses is enhanced by ultraclean laboratory practices, non-destructive extraction and clean-up steps and the use of low-volume, high-efficiency HPLC separation for various classes of organic contaminants. In the light of these new developments conventional procedures for chlorobiphenyl analysis are evaluated.

Description: Eine Analysenmethode, die für die organische Spurenstoff-Bestimmung im Meerwasser konzipiert ist, wurde auf die Analytik von Grund- und Trinkwasser übertragen. Es zeigte sich, daß mit den üblichen Meßmethoden keine ausreichenden Analysen möglich sind. Hauptprobleme sind zu geringe Probenvolumina (1-10 1), ungenügende Clean-up Methoden und unvollständige gaschromatographische Trennungen von koeluierenden Verbindungen. Die Konzentrationen an Chlorbiphenylen im untersuchten Trinkwasser lagen zwischen 0,1 und 50 pg/1 und somit weit unter den nach der Trinkwasserverordnung vom Dezember 1990 zulässigen Höchstmengen. Die Gehalte waren aber zum Teil höher als im Meerwasser der als sehr belastet angesehenen Nordsee und Ostsee. Unter diesen Gesichtspunkten, wie auch unter Berücksichtigung der unterschiedlichen Toxizitäten der Einzelkomponenten, erscheint der in der Trinkwasserverordnung vorgeschriebene Grenzwert viel zu hoch

Description: Gas chromatography-mass spectrometry (GC-MS) analyses of organic concentrates from eastern Mediterranean surface water show that dissolved fossil fuel residues are dominated by unsubstituted aromatic hydrocarbons and heterocyclic aromatics and thus resemble products of incomplete combustion. Deviating from this interpretation, preferential photochemical oxidation of alkyl-substituted aromatics is suggested as the principal causative mechanism, although, especially near land-based sources. the influence of combustion-derived unsubstituted aromatics is not defined. Total concentrations of dissolved aromatics as determined by GC-FID (flame ionization detection) and GC-MS from a limited data subset were in reasonable agreement with UV fluorescence measurements of dissolved/dispersed oil residues. The same preponderance of unsubstituted aromatics over their alkyl derivatives was found in extracts of the particulate phase, but concentrations were small relative to alkanes and/or alkenes of recent marine biosynthetic origin. CPI (carbon preference index) values of higher molecular weight n-alkanes indicated varying contributions of plant waxes to the particulate hydrocarbon pool. CPI values of corresponding dissolved n-alkanes were found to be near unity, indicating fossil fuel origin. Despite differences in higher molecular weight n-alkane CPI values and the predominance of recent biosynthetic aliphatics, the similarity of dissolved and particulate aromatic fractions suggests limited adsorption by particles of fossil fuel derived hydrocarbons and heterocyclics.

Description: Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000 km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited:on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote environments. Snow collected at various depths from a core of up to 7.7 m deep, at Mt. Tateyama (2450 m), Japan, showed the highest concentrations of PFASs in the surface layer and the concentrations decreased with increasing depth for most PFASs, except for perfluorobutanesulfonate (PFBS). Downward movement of highly water soluble PFASs such as PFBS, following melting and freezing cycles of snow, was evident from the analysis of snow core

Description: From October 2008 to November 2010, CH3I concentrations were measured in the Kiel Fjord together with potentially related biogeochemical and physical parameters. A repeating seasonal cycle of CH3I was observed with highest concentrations in summer (ca. 8.3 pmol L−1; June and July) and lowest concentrations in winter (ca. 1.5 pmol L−1; December to February). A strong positive correlation at zero lag between [CH3I] and solar radiation (R2 = 0.93) was observed, whereas correlations with other variables (SST, Chlorophyll a) were weaker, and they lagged CH3I by ca. 1 month. These results appear consistent with the hypothesis that SSR is the primary forcing of CH3I production in surface seawater, possibly through a photochemical pathway. A mass balance of the monthly averaged data was used to infer mean rates of daily net production (Pnet) and losses for CH3I over the year. The sea-to-air flux of CH3I in the Kiel Fjord averaged 3.1 nmol m−2 d−1, the mean chemical loss rate was 0.047 pmol L−1 d−1, and Pnet varied systematically from winter to summer (from 0 to 0.6 pmol L−1 d−1). Pnet was correlated at zero lag with SST, SSR, and Chla (R2 = 0.55, 0.67, and 0.73, respectively, p 〈〈 0.01). The lagged cross-correlation analysis indicated that SSR led Pnet by 1 month, whereas the strongest cross correlations with Chla were at lags of 0 to +1 month, and SST lagged Pnet by 1 month. The broad seasonal peak of Pnet makes it difficult to determine the key factor controlling CH3I net production using in situ concentration data alone.

Description: In order to investigate production pathways of methyl iodide and controls on emissions from the surface ocean, a set of repeated in vitro incubation experiments were performed over an annual cycle in the context of a time series of in situ measurements in Kiel Fjord (54.3°N, 10.1°E). The incubation experiments revealed a diurnal variation of methyl iodide in samples exposed to natural light, with maxima during day time and losses during night hours. The amplitude of the daily accumulation varied seasonally and was not affected by filtration (0.2 µm), consistent with a photochemical pathway for CH3I production. The methyl iodide loss rate at nighttime correlates with the concentration accumulated during daytime suggesting a first-order loss mechanism (R2 = 0.29, p 〈〈 0.01). Daily (24 h) net production (Pnet) was similar in magnitude between in vitro and in situ mass balances. However, the estimated gross production (Pgross) of methyl iodide ranged from −0.07 to 2.24 pmol L−1 d−1 and was up to 5 times higher in summer than Pnet calculated from the in situ study. The large excess of Pgross over Pnet in summer revealed by the incubation experiments is a consequence of large losses of CH3I by as-yet uncharacterized processes (e.g., biological degradation or chemical pathways other than Cl− substitution).