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Anaerobic ammonium oxidation (anammox) involves the microbiological oxidation of ammonium with nitrite as the electron acceptor and dinitrogen gas as the main product. The Scalindua species, an anammox genus that dominates natural habitats, plays an important role in catalysing the loss of nitrogen from marine environments. Until now, a few Scalindua species have been reported to be enriched from sea sediments. The objective of this study is to enrich marine anammox bacteria with coastal sediments in Hiroshima Bay as the inocula. The enrichment was achieved using a continuous upflow column reactor with synthetic sea water containing ammonium and nitrite. After 48 days of incubation, a simultaneous decrease in ammonium and nitrite was observed. A total nitrogen removal rate of 1.16 kg-N m-3 day-1 was attained after 306 days of incubation when the nitrogen loading rate was 1.32 kg-N m-3 day-1. Phylogenetic analysis revealed that the sequence similarity between the marine anammox-like bacteria in this reactor and the unidentified Candidatus Scalindua sp. was 96-98%. We successfully enriched marine anammox bacteria in the sediments of Hiroshima Bay by using synthetic sea water. Further studies are needed to investigate the characteristics of marine anammox bacteria, including optimal pH, temperature, and nitrogen loading rate. [ABSTRACT FROM AUTHOR]

In order to consider the total atmospheric loadings of the PAHs (polycyclic aromatic hydrocarbons) from traffic activities, the emission factors of PAHs were estimated and from the obtained emission factors and vehicle transportation statistics, total atmospheric loadings were integrated and the loadings into the water body were estimated on a regional scale. The atmospheric concentration of PAHs was measured at the roadside of a road with heavy traffic in the Hiroshima area in Japan. The samplings were conducted in summer and winter. Atmospheric particulate matters (fine particle, 0.6-7 mm; coarse particle, over 7mm) and their PAH concentration were measured. Also, four major emission sources (gasoline and diesel vehicle emissions, tire and asphalt debris) were assumed for vehicle transportation activities, the chemical mass balance method was applied and the source partitioning at the roadside was estimated. Furthermore, the dispersion of atmospheric particles from the vehicles was modelled and the emission factors of the sources were determined by the comparison to the chemical mass balance results. Based on emission factors derived from the modelling, an atmospheric dispersion model of nationwide scale (National Institute of Advanced Industrial Science and Technology - Atmospheric Dispersion Model for Exposure and Risk assessment) was applied, and the atmospheric concentration and loading to the ground were calculated for the Hiroshima Bay watershed area. [ABSTRACT FROM AUTHOR]