Studies on the accumulation and transformation of arsenic in freshwater organisms II. Accumulation and transformation of arsenic compounds by Tilapia mossambica

Bioaccumulation and biotransformation of arsenic (As) compounds in freshwater Tilapia mossambica was investigated. The direct accumulation of As by T mossambica was proportional to the concentration of arsenicals in water. Small amounts of accumulated As were transformed to methylated As, including trimethylarsenic (TMA) species. Accumulation and transformation of As(III) by T. mossambica via freshwater food chain results in the transformation of As(III) to As(V) with little biomethylation of accumulated As. Approximately 90% of accumulated As was depurated to water.     

Long-Term Observation of Asian Dust in Changchun and Kagoshima

Monitoring of Asian dust at two stations in Changchun, Jilin Province in northeast China, and Kagoshima, southwest Japan, is discussed. In Changchun, interval records were made with digital and video cameras from 18 March 2003. In Kagoshima, a web camera system to monitor volcanic clouds has been working since December 2000, which also provides data for studies of dust. A heavy dust episode on 11 November 2002, affecting both stations, was detected using 11 and 12 μm channels of NOAA/AVHRR. We observed dust in Changchun on 26 March, 7, 14–16 April, 1–2, 8, 10, 19 May, 8, 23 June, and 12 July in 2003. The observed images corresponded well to NOAA/AVHRR imagery and with 8.6, 11 and 12 μm Terra/MODIS results, although conditions were too cloudy for satellite verification in some cases.     

Bioremediation of petroleum‐impacted soils from investigation‐derived wastes

Optimal conditions for bioremediation of investigation‐derived wastes from petroleum‐impacted soils (PIS) were determined through biotreatability experiments. The PIS was collected as extruded cores obtained during sample drilling. These samples were processed into workable media prior to treatment in bioreactors. Soil moisture content in the bioreactors was adjusted to 30 percent, 40 percent, 50 percent (control), and 60 percent, dry‐weight basis, and nutrient levels were adjusted by applying fertilizer, yielding carbon (C) to nitrogen (N) ratios of 20:1, 10:1, and 5:1, versus a control C:N ratio of 140:1. Temperature, pH, viable bacterial plate counts, contaminant degradation rate, and microbial respiration were monitored. Concentrations of three selected branched alkanes in the aviation fuel contaminant, measured by gas chromatography, decreased for most treatments. The greatest degradation occurred with a moisture content of 40 percent and C:N ratio of 5:1. Increased contaminant degradation was consistent with increased microbial activity measured by respiration. There was poorer correlation between contaminant degradation and viable plate counts, which suggests that respirometry is a better measure of activity of the microbial population responsible for contaminant degradation. General plate counts, which enumerate only a fraction of the total population, may not be a reliable quantitative indicator of the actual microorganism population that is responsible for degradation. © 2003 Wiley Periodicals, Inc.     

Temporal Trends of Non-sea Salt Sulfate and Nitrate in Wet Deposition in Japan

Temporal trends of non-sea salt (nss-) sulfate and nitrate were analyzed from nationwide precipitation chemistry measurements provided by the Ministry of the Environment (MOE) for the 1988–2002 fiscal years (April–March). The concentrations and deposition of nss-sulfate were found to be decreasing, and those of nitrate were stable or slightly increasing at most sites. These deposition trends were discussed from the viewpoint of emissions of SO₂ and NO_X during the period of interest. Because monitoring techniques have changed in the number of active sites, samplers, and analytical methods during the operation period, the median of all annual depositions measured in Japan in a specific year was selected as the annual representative. The contribution of specific emission sources was also calculated for 1990 on the basis of the nss-sulfate and nitrate deposition in Japan obtained with a model simulation in which the model did not include volcanic emissions from Mt. Oyama, Miyakejima Island, which began to erupt suddenly and violently in 2000. For nss-sulfate, the calculated deposition agrees well with the intensity and trends of the median up to 1999. After 2000, a higher deposition than calculated in the preceding years was evident, which is attributable to the volcanic SO₂ from Mt. Oyama. For nitrate, both the calculated and observed depositions were slightly increasing; however, the calculation was found to exceed the observation.