Aerosol chemical characteristics of an island site in the Bay of Bengal (Bhola-Bangladesh)

Aerosol constituents (elemental carbon, organic carbon, soluble ions including organic acids, and selected trace metals) were investigated from samples of a field campaign taking place at Bhola Island in the Bay of Bengal (Bangladesh). The campaign took place in the pre-monsoon season (May 2001) using low volume samplers. Carbonaceous material comprised the majority of the analysed components. The average concentrations of EC and OC were 2.8 and 4.6 microg m(-3), respectively. Oxalic acid was the most abundant dicarboxylic acid (average 268 ng m(-3)) followed by malonic and malic acid. The contribution of carboxylic acids-carbon to organic carbon was 2.0%. Average concentrations observed for sulfate and nitrate were 3.7 microg m(-3) and 1.5 microg m(-3). Two different types of aerosol were identified at the rural background site on Bhola Island during southerly synoptic flow by means of trajectory analysis: air masses were transported from the Bay of Bengal to the sampling site in all cases. However, during "Period 1" they experienced longer residence times over the Indian Ocean, while the "Period 2" trajectories came along the Indian coast or passed over the Indian continent. During Period 1 the concentration levels of soluble ions were a factor of 4-6 lower than during Period 2. The concentrations of EC, OC and K differed less than a factor of 1.5 between the two periods. The Period 1 aerosol showed similarities to the haze layers observed during winter-monsoon conditions south of India during the INDOEX experiment. Based on EC/TC and K/EC ratios we find that around 80% of the carbonaceous aerosol from Period 1 in Bhola is from fossil fuel and only around 50% from Period 2. Absolute concentrations of carbonaceous species, soluble ions and trace metals indicate that the background site on Bhola Island is affected by emissions from urbanized regions of Southeast Asia.     

Immunity in children with exposure to environmental lead: II. Effects on humoral immunity

Lead has been found to depress the immune system in animal studies at levels far below those responsible for overt toxicity. Literature studies in animal systems most clearly showed an effect of lead on response to a specific immunogenic stimulus. Data are sparse concerning the effects of lead on the immune system in the human population at greatest risk for exposure-children up to six years of age. This portion of the Phase I study reports concentrations of IgG, IgM, IgA, and IgE, as well as antibody titers to the specific antigenic stimuli provided by the vaccines against diphtheria, tetanus, and Rubella. The study population consisted of a group of 193 children, ages 9 months to 6 years, who participate in the WIC (Women, Infants and Children) and Lead Poisoning Prevention Programs in the urban area of Springfield-Greene County Missouri. Blood lead levels ranged from 1 to 50 g dL^–1. Total Ig levels were determined and the data were analysed. No consistent significant differences were observed among the risk categories in the five age groups examined. A single Ig class in each of three age groups showed apparent significant differences among the various risk categories, but these differences were not correlated with blood lead. An analysis of specific antibody titers to diphtheria, tetanus, and Rubella was performed. Regression analyses of current data in Phase I of this study suggest a detrimental effect of lead on the antibody titres to diphtheria and Rubella.     

Geochemical transformation of soil cover and vegetation in a drained floodplain lake affected by long-term discharge of effluents from rayon industry plants,lower Don River Basin,Southern Russia

Environmental Geochemistry and Health - Lake Atamanskoye is one of the most polluted aquatic environments in the South of Russia. This water body was affected by long-term pollution by effluent...     

Filamentous scum bacteria in activated sludge plants: detection and identification quality by conventional activated sludge microscopy versus fluorescence in situ hybridization.

Detection of filamentous bacteria morphotypes involved in scum formation in activated sludge wastewater treatment plants by conventional sludge microscopy is often doomed to fail because of morphological and taxonomical variations. The aim of this study is to compare detection, identification, and quantification quality of filamentous "scum bacteria" found by conventional activated sludge microscopy and fluorescence in situ hybridization (FISH). In the case of filamentous Microthrix parvicella and Eikelboom morphotypes 1863 and 1851, conventional activated sludge microscopy and FISH results correspond well. In contrast, conventional activated sludge microscopy overlooks nocardioform actinomycete and type 1863 single cells. On the other hand, FISH underestimates filamentous nocardioform actinomycetes and morphotypes 0041/0675 or 0092 because of insufficient cell wall permeability or because of their taxonomic variability, with a resulting inadequacy of previously published probes. Nostocoida limicola morphotype results are still inconclusive because of low bacteria numbers being available in situ and the enormous taxonomic variability within this group.