Anna Orlikowska

Environmental context: Halocarbons are trace gases important in atmospheric ozone chemistry whose biogenic production – among other factors – depends on light-induced stress of marine algae. Several studies have confirmed this effect in laboratory experiments but knowledge in natural systems remains sparse. In mesocosm experiments, which are a link between field and laboratory studies, we observed that the influence of natural levels of ultraviolet radiation on halocarbon dynamics in the marine surface waters was either insignificant or concealed by the complex interactions in the natural systems. The aim of the present study was to evaluate the influence of different light quality, especially ultraviolet radiation (UVR), on the dynamics of volatile halogenated organic compounds (VHOCs) at the sea surface. Short term experiments were conducted with floating gas-tight mesocosms of different optical qualities. Six halocarbons (CH3I, CHCl3, CH2Br2, CH2ClI, CHBr3 and CH2I2), known to be produced by phytoplankton, together with a variety of biological and environmental variables were measured in the coastal southern Baltic Sea and in the Raunefjord (North Sea). These experiments showed that ambient levels of UVR have no significant influence on VHOC dynamics in the natural systems. We attribute it to the low radiation doses that phytoplankton cells receive in a normal turbulent surface mixed layer. The VHOC concentrations were influenced by their production and removal processes, but they were not correlated with biological or environmental parameters investigated. Diatoms were most likely the dominant biogenic source of VHOCs in the Baltic Sea experiment, whereas in the Raunefjord experiment macroalgae probably contributed strongly to the production of VHOCs. The variable stable carbon isotope signatures (d13C values) of bromoform (CHBr3) also indicate that different autotrophic organisms were responsible for CHBr3 production in the two coastal environments. In the Raunefjord, despite strong daily variations in CHBr3 concentration, the carbon isotopic ratio was fairly stable with a mean value of –26 ‰. During the declining spring phytoplankton bloom in the Baltic Sea, the d13C values of CHBr3 were enriched in 13C and showed noticeable diurnal changes (–12 ‰ ± 4). These results show that isotope signature analysis is a useful tool to study both the origin and dynamics of VHOCs in natural systems.

Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr₃), dibromomethane (CH₂Br₂) and methyl iodide (CH₃I). The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface observations within the HalOcAt (Halocarbons in the Ocean and Atmosphere) database (https://halocat.geomar.de/). Global maps of marine and atmospheric surface concentrations are derived from the data which are divided into coastal, shelf and open ocean regions. Considering physical and biogeochemical characteristics of ocean and atmosphere, the open ocean water and atmosphere data are classified into 21 regions. The available data are interpolated onto a 1°×1° grid while missing grid values are interpolated with latitudinal and longitudinal dependent regression techniques reflecting the compounds' distributions. With the generated surface concentration climatologies for the ocean and atmosphere, global sea-to-air concentration gradients and sea-to-air fluxes are calculated. Based on these calculations we estimate a total global flux of 1.5/2.5 Gmol Br yr⁻¹ for CHBr₃, 0.78/0.98 Gmol Br yr⁻¹ for CH₂Br₂ and 1.24/1.45 Gmol Br yr⁻¹ for CH₃I (robust fit/ordinary least squares regression techniques). Contrary to recent studies, negative fluxes occur in each sea-to-air flux climatology, mainly in the Arctic and Antarctic regions. "Hot spots" for global polybromomethane emissions are located in the equatorial region, whereas methyl iodide emissions are enhanced in the subtropical gyre regions. Inter-annual and seasonal variation is contained within our flux calculations for all three compounds. Compared to earlier studies, our global fluxes are at the lower end of estimates, especially for bromoform. An under-representation of coastal emissions and of extreme events in our estimate might explain the mismatch between our bottom-up emission estimate and top-down approaches.

Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr₃), dibromomethane (CH₂Br₂) and methyl iodide (CH₃I). The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface observations within the HalOcAt (Halocarbons in the Ocean and Atmosphere) database (https://halocat.geomar.de/). Global maps of marine and atmospheric surface concentrations are derived from the data which are divided into coastal, shelf and open ocean regions. Considering physical and biogeochemical characteristics of ocean and atmosphere, the open ocean water and atmosphere data are classified into 21 regions. The available data are interpolated onto a 1°×1° grid while missing grid values are interpolated with latitudinal and longitudinal dependent regression techniques reflecting the compounds' distributions. With the generated surface concentration climatologies for the ocean and atmosphere, global sea-to-air concentration gradients and sea-to-air fluxes are calculated. Based on these calculations we estimate a total global flux of 1.5/2.5 Gmol Br yr⁻¹ for CHBr₃, 0.78/0.98 Gmol Br yr⁻¹ for CH₂Br₂ and 1.24/1.45 Gmol Br yr⁻¹ for CH₃I (robust fit/ordinary least squares regression techniques). Contrary to recent studies, negative fluxes occur in each sea-to-air flux climatology, mainly in the Arctic and Antarctic regions. "Hot spots" for global polybromomethane emissions are located in the equatorial region, whereas methyl iodide emissions are enhanced in the subtropical gyre regions. Inter-annual and seasonal variation is contained within our flux calculations for all three compounds. Compared to earlier studies, our global fluxes are at the lower end of estimates, especially for bromoform. An under-representation of coastal emissions and of extreme events in our estimate might explain the mismatch between our bottom-up emission estimate and top-down approaches.

Under a small project, one-year-old Scots Pine needles collected from 25 spatially distant sites were examined in monitoring the extent of environmental diffusion and possible sources of polychlorinated biphenyls (PCBs) in ambient air, their depositions and uptake by plants in Poland. The congener-specific determination of planar and non-planar chlorobiphenyls was achieved by isotope dilution HRGC-HRMS method after a highly refined extraction on multi-layer column of silica gel and alumina layer and clean-up, and fractionations, followed by Hypercarb-HPLC and PYE-HPLC sub-fractionation steps. Contents of 117 chlorobiphenyls determined in pine needles varied for the 25 sites studied and is between 2.7 and 49 ng/g wet weight. The PCBs pollution and congener-specific composition of pine needles to some degree varied according to the site or region surveyed depending on population density and industrialization. Many of the country-side areas showed lower concentrations between 2.7 and 8.9 ng/g ww. Pine needles in areas close to well populated and industrial regions of Opole, Kutno, Włocławek and Dębica showed the highest PCB pollution with concentrations varying between 30 and 49 ng/g ww. The Kutno site showed the highest pollution and this fact probably can be explained by possible emission from transformer manufactures located at some distance west of the Kutno area. Factor analysis (FA) and depending on the site revealed on relationship of PCBs composition of pine needles both with highly chlorinated PCB constituents of the mixtures such as Chlorofen, Aroclor 1254, Aroclor 1268 and Sovol but also of lower chlorinated PCB constituents of Aroclor 1242, Aroclor 1248, Clophen A40 or Delor 103. Thermal processes were considered a less significant source of PCBs in ambient air over Poland compared to evaporative sources related to technical PCB formulations. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Environmental Science and Health: Part A to view the free supplemental file.

Environmental context. Volatile organic compounds (VOCs) play a significant role in the global climate and are engaged in several atmospheric reactions. Relatively large amounts of VOCs are emitted from coastal waters, which is why these zones are expected to have significant impact on the atmospheric chemistry. The abundance of a single compound depends on its source and removal processes as well as on environmental parameters. Thus, seasonal changes can greatly affect the occurrence and behaviour of these trace gases. In order to investigate temporal changes in combination with the influence of different environmental parameters on the concentration and the composition of volatile organic compounds (VOCs), seawater samples from the coastal Baltic Sea were weekly measured from January to November 2008. In most cases, concentrations of VOCs varied seasonally and were influenced by changes in temperature and light conditions or biological species composition. A nearly two-fold increase in the mean concentration was noticed for isoprene, iodomethane and bromoform in the season with higher water temperature. The strongest flux of dimethylsulfide to the atmosphere appeared in May and July. Its high production was related to the presence of Prymnesiophyceae. The highest concentrations of diiodomethane and chloroiodomethane were observed with the spring and autumn phytoplankton bloom; their distribution was strongly controlled by light intensity. Flux calculations showed that coastal regions can affect local atmosphere, especially during biologically active periods. The strongest emission of bromoform and iodomethane was in July and August. The data presented here highlights the need to include seasonal cycles when calculating the global budgets and modelling sea–air fluxes of trace gases.

The Japanese Kanechlor technical PCB formulations such as KC-300, KC-400, KC-500, KC-600 and KC-1000 have been examined for possible contamination with by-side PCDD/Fs. 75 PCDDs and 135 PCDF have been determined using isotope dilution, separation and enrichment on silica gel impregnated with activated carbon, and final HRGC/HRMS measurement. MonoCDDs to OCDD were absent in KC-300, KC-600 and KC-1000. Tetra- and PentaCDDs occurred at > 1 ng/g in KC-400 and KC-500. The Kanechlors were contaminated with nearly all 135 PCDFsw. In parallel with an increasing degree of chlorination of a particular Kanechlor formulation examined increased also the content of more chlorinated PCDFs. In term of total dioxin-like toxicity and TEQ loads the KC-500 contained highly toxic PCDD/Fs at 270 ng TEQ/g and followed by KC-400 with 269 ng TEQ/g, KC-600 with 188 ng TEQ/g, KC-1000 with 164 ng TEQ/g and KC-300 with 79 ng TEQ/g. From 99.5 to 100% of PCDD/Fs toxicity found in the Kanechlors was from PCDFs.