PM10-bound polycyclic aromatic hydrocarbons (PAHs) in the Greater Area of Athens, Greece

Polycyclic aromatic hydrocarbons (PAHs) associated to ambient PM10 were determined at four sites within the Greater Athens Area (GAA), Greece, during the period May 2001-June 2002. Daily average PM10 samples were collected using reference samplers installed in two urban locations (Maroussi, MAR and Aristotelous, ARI), a mixed urban-industrial location (Elefsina, ELE), and a background location (Thracomacedones, THR). Spatial and temporal variation of ambient PAH levels and possible relationships with conventional air pollutants and meteorological parameters were investigated. Moreover, source identification was attempted using diagnostic ratios. The PAH concentrations observed in this study, even in downtown Athens, were towards the lowest end of the range of values reported for other European urban locations. The mean concentration of the well known carcinogen B[alpha]Py was at all four sites below the proposed value of 1 ng m-3 (annual average assessment threshold). Automobile traffic was identified as the major PAH source in the GAA exhibiting greatest contribution in the urban sites.     

Growth of Azotobacter chroococcum in chemically defined media containing p-hydroxybenzoic acid and protocatechuic acid

Growth and utilization of different phenolic acids present in olive mill wastewater (OMW) by Azotobacter chroococcum were studied in chemically defined media. Growth and utilization of phenolic acids were only detected when the microorganism was cultured on p-hydroxybenzoic acid at concentration from 0.01% to 0.5% (w/v) and protocatechuic acid at concentration from 0.01% to 0.3% (w/v) as sole carbon sources suggesting that only these phenolic compounds could be utilized as a carbon source by A. chroococcum. Moreover when culture media were added with a mixture of 0.3% of protocatechuic acid and 0.3% p-hydroxybenzoic acid, the microorganism degradated in first place protocatechuic acid and once the culture medium was depleted of this compound, the degradation of p-hydroxybenzoic acid commenced very fast.     

Bioavailability of contaminants estimated from uptake rates into soil invertebrates

It is often argued that the concentration of a pollutant inside an organism is a good indicator of its bioavailability, however, we show that the rate of uptake, not the concentration itself, is the superior predictor. In a study on zinc accumulation and toxicity to isopods (Porcellio scaber) the dietary EC(50) for the effect on body growth was rather constant and reproducible, while the internal EC(50) varied depending on the accumulation history of the animals. From the data a critical value for zinc accumulation in P. scaber was estimated as 53 microg/g/wk. We review toxicokinetic models applicable to time-series measurements of concentrations in invertebrates. The initial slope of the uptake curve is proposed as an indicator of bioavailability. To apply the dynamic concept of bioavailability in risk assessment, a set of representative organisms should be chosen and standardized protocols developed for exposure assays by which suspect soils can be evaluated.     

Photocatalytic degradation of azo dyes by nitrogen-doped TiO2 nanocatalysts

This study examined the photocatalytic degradation of three azo dyes, acid orange 7 (AO7), procion red MX-5B (MX-5B) and reactive black 5 (RB5) using a new type of nitrogen-doped TiO2 nanocrystals. These newly developed doped titania nanocatalysts demonstrated high reactivity under visible light (lambda>390 nm), allowing more efficient usage of solar light. The doped titania were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Experiments were conducted to compare the photocatalytic activities of nitrogen-doped TiO2 nanocatalysts and commercially available Degussa P25 powder using both UV illumination and solar light. It is shown that nitrogen-doped TiO2 after calcination had the highest photocatalytic activity among all three catalysts tested, with 95% of AO7 decolorized in 1 h under UV illumination. The doped TiO2 also exhibited substantial photocatalytic activity under direct sunlight irradiation, with 70% of the dye color removed in 1h and complete decolorization within 3 h. Degussa P25 did not cause detectable dye decolorization under identical experimental conditions using solar light. The decrease of total organic carbon (TOC) and evolution of inorganic sulfate (SO4(2-)) ions in dye solutions were measured to monitor the dye mineralization process.     

Uptake of heavy metals and As by Brassica juncea grown in a contaminated soil in Aznalcóllar (Spain): the effect of soil amendments

Two crops of Brassica juncea (L.) Czern. were grown in a field experiment, at the site affected by the toxic spillage of acidic, metal-rich waste in Aznalcóllar (Seville, Spain), to study its metal accumulation and the feasibility of its use for metal phytoextraction. The effects of organic soil amendments (cow manure and mature compost) and lime on biomass production and plant survival were also assessed; plots without organic amendment and without lime were used as controls. Plots, with or without organic amendment, having pH < 5 were limed for the second crop. Soil acidification conditioned plant growth and metal accumulation. The addition of lime and the organic amendments achieved higher plant biomass production, although effects concerning metal bioavailability and accumulation were masked somewhat by pH variability with time and between and within plots. Tissue metal concentrations of B. juncea were elevated for Zn, Cu and Pb, especially in leaves of plants from plots with low pH values (maxima of 2029, 71 and 55 microg g(-1), respectively). The total uptake of heavy metals in the plants was relatively low, emphasising the problems faced when attempting to employ phytoextraction for clean-up of pluri-contaminated sites.     

Organochlorine residues in odontocete species from the southeast coast of India

Blubber from bottle-nose dolphins, spinner dolphins, humpback dolphin (Tursiops truncatus, Stenella longirostris and Sousa chinensis) were collected from the Bay of Bengal (southeast coast of India) and analyzed for the organochlorine pesticides hexachlorocyclohexane (HCHs), p,p'-dichlorodiphenyl trichloroethane (DDTs), and polychlorinated biphenyls (PCBs). All nine specimens analyzed contained considerable levels of all the three chemical classes where DDT was in the range of 3330-23330 ng/g; HCHs in the range of 95-765 ng/g; and PCBs in the range of 210-1220 ng/g (wet weight basis). The reasons for this and the variations in the isomer pattern of HCHs and DDT and its metabolites in marine mammal tissues are discussed.     

Halogenated compounds in a dated sediment core of the Teltow Canal, Berlin: time related sediment contamination

To study the recent contamination history of DDT (1,1,1-trichloro-2,2-bis(chlorophenyl)ethane) and its metabolites, as well as methoxychlor (1,1,1-trichloro-2,2-bis(p-methoxyphenyl)ethane), chlorfenson (4-chlorophenyl-p-chlorobenzenesulfonate), and further halogenated aromatics, a sediment core was collected from the Teltow Canal in Berlin (Germany). The sampling site is located nearby a former industrial point source, where recently analyses on pre-samples have indicated high concentrations of halogenated organic compounds. The deposition time of the investigated sediments was determined by gamma-spectrometrical dating. Pollution trends of selected contaminants were attributed to a time period between 5 and 10 years. Concentration profiles reflect not only the recent pollution history of these compounds, but also the time-depending effects of the ban, restriction and termination of DDT-production in the German Democratic Republic (GDR). DDT and other chlorinated aromatic compounds were produced onsite until the late 1980s. Maximum values of 133 mg kg(-1) (dry weight) for p,p'-DDD (1,1-dichloro-2,2-bis(chlorophenyl)ethane) and approximately 100 mg kg(-1) (dry weight) for p,p'-DDMS (1-chloro-2,2-bis(chlorophenyl)ethane), main metabolites of the anaerobic degradation of DDT, were determined. The occurrence of all selected contaminants, most of which have been banned more than 10 years ago, demonstrate recent contamination pathways, and the necessity of a continuous long-term monitoring of the affected environment.     

Photo-Fenton-assisted ozonation of p-Coumaric acid in aqueous solution

The degradation of p-Coumaric acid present in olive oil mill wastewater was investigated as a pretreatment stage to obtain more easily biodegradable molecules, with lower toxicity that facilitates subsequent anaerobic digestion. Thus, photo-Fenton-assisted ozonation has been studied and compared with ozonation at alkaline pH and conventional single ultraviolet (UV) and acid ozonation treatments. In the combined process, the overall kinetic rate constant was split into various components: direct oxidation by UV light, direct oxidation by ozone and oxidation by hydroxyl radicals. Molecular and/or radical ozone reaction was studied by conducting the reaction in the presence and absence of tert-butylalcohol at pHs 2, 7 and 9. Ozone oxidation rate increases with pH or by the addition of Fenton reagent and/or UV radiation due to generation of hydroxyl radicals, *OH. Hydrogen peroxide and ferrous ion play a double role during oxidation since at low concentrations they act as initiators of hydroxyl radicals but at high concentrations they act as radical scavengers. Finally, the additional levels of degradation by formation of hydroxyl radicals have been quantified in comparison to the conventional single processes and an equation is proposed for the reaction rate as a function of studied operating variables.     

The impact of pumped water from a de-watered Magnesian limestone quarry on an adjacent wetland: Thrislington, County Durham, UK

Although quarrying is often cited as a potential threat to wetland systems, there is a lack of relevant, quantitative case studies in the literature. The impact of pumped groundwater discharged from a quarry into a wetland area was assessed relative to reference conditions in an adjacent fen wetland that receives only natural runoff. Analysis of vegetation patterns at the quarry wetland site, using Detrended Correspondence Analysis and the species indicator values of Ellenberg, revealed a clear disparity between community transitions in the quarry wetland and the reference site. Limited establishment of moisture-sensitive taxa, the preferential proliferation of robust wetland species and an overall shift towards lower species diversity in the quarry wetland were explicable primarily by the physico-chemical environment created by quarry dewatering. This encompassed high pH (up to 12.8), sediment-rich effluent creating a nutrient-poor substrate with poor moisture retention in the quarry wetland, and large fluctuations in water levels.     

Environmental threats to buried archaeological remains

The last century's environmental pollution has created health problems, acidification of ground and lakes, and serious damage to our cultural heritage. Outdoor monuments suffer from this pollution, but so do buried archaeological remains. However, research on the deterioration of archaeological artifacts underground has so far been limited, and it is important to draw attention to this neglected field. This article presents results obtained at the Swedish National Heritage Board on the degradation of archaeological objects of bronze and iron and of bones from prehistoric graves, materials of which seem to be most affected by pollutants. The investigation methods, which were employed, are described. Other relevant studies are briefly reviewed. It is obvious that the deterioration rate of archaeological artifacts, especially of inorganic materials, has accelerated in recent years, and that this increased deterioration to a large part can be attributed to anthropogenic pollution. Regions that might be endangered are exemplified.