Dispersion of Pollutants in Street Canyon under Traffic Induced Flow and Turbulence

A 3-D Eulerian-Lagrangian approach to moving vehicles is presented that takes into account the traffic induced flow rate and turbulence. The method is applied to pollutants dispersion in a street canyon. The approach is based on CFD calculations using Eulerian approach to the continuous phase and Lagrangian approach to the "discrete phase" of moving objects - vehicles. A commercial CFD code StarCD was used into which the Lagrangian model was integrated. As an example a street canyon is taken into consideration. It has the length of 50 m and the aspect ratio of 1.27. The speed of wind was assigned values of 4, 7 and 12 m/s at the altitude of 300 m. The total height of the domain is 115 m. In the study different traffic situations are considered, namely one-way and two-way traffic with different traffic rates per lane. The predictions show that different traffic situations affect pollutants dispersion in the street canyon and that there are also differences in the pollutants dispersion in case of one- and two-way traffic.     

Heavy Metal Concentrations in and Around Households Near a Secondary Lead Smelter

Housedusts and garden soils were sampled in 14 houses in the vicinity of a secondary Pb smelter and analysed for concentrations of Pb, Zn, Cu, Cd, As, and Hg. Sixty-one topsoil samples were also taken from a 2 km² grid covering the smelter grounds and surrounding residential areas and analysed for concentrations of Pb, Zn, Cd and Cu. Contour maps generated from the grid data indicate significant contamination in the area (maximum Pb concentration 58 500 g g^-1), particularly down-wind of the smelter grounds. A geometric mean Pb concentration of 2225 g g^-1 was recorded in garden soil and similarly elevated levels were recorded for Zn, Cd, As and Sb. In housedusts, a geometric mean Pb concentration of 1668 g g^-1 was observed. Whilst housedust metal concentrations were generally elevated, compared to other urban or residential areas, there appears to be a large degree of attenuation of the metals between the exterior and interior environments of the homes studied. A significant correlation was not recorded between metal concentrations of garden soils and housedusts. There were significant correlations for: distance from the smelter against garden soil metal concentrations; garden soil metal concentrations against each other; housedust metal concentrations against each other; and house age against garden soil metal concentrations.     

Root uptake of atenolol,sulfamethoxazole and carbamazepine,and their transformation in three soils and four plants

Soils can be contaminated by pharmaceuticals. The aim of this study was to evaluate the impact of soil conditions (influencing sorption and persistence of pharmaceuticals in soils) and plant type on the root uptake of selected pharmaceuticals and their transformation in plant-soil systems. Four plants (lamb’s lettuce, spinach, arugula, radish) planted in 3 soils were irrigated for 20 days (26) with water contaminated by one of 3 pharmaceuticals (carbamazepine, atenolol, sulfamethoxazole) or their mixture. The concentrations of pharmaceuticals and their metabolites in soils and plant tissues were evaluated after the harvest. Sulfamethoxazole and atenolol dissipated rapidly from soils. The larger concentrations of both compounds and an atenolol metabolite were found in roots than in leaves. Sulfamethoxazole metabolites were below the limits of quantifications. Carbamazepine was stable in soils, easily uptaken, accumulated, and metabolized in plant leaves. The efficiency of radish and arugula (both family Brassicaceae) in metabolizing was very low contrary to the high and moderate efficiencies of lamb’s lettuce and spinach, respectively. Compounds’ transformations mostly masked the soil impact on their accumulation in plant tissues. The negative relationships were found between the carbamazepine sorption coefficients and its concentrations in roots of radish, lamb’s lettuce, and spinach.

     

The formation and fate of chlorinated organic substances in temperate and boreal forest soils

Background, aim and scope  Chlorine is an abundant element, commonly occurring in nature either as chloride ions or as chlorinated organic compounds (OCls). Chlorinated organic substances were long considered purely anthropogenic products; however, they are, in addition, a commonly occurring and important part of natural ecosystems. Formation of OCls may affect the degradation of soil organic matter (SOM) and thus the carbon cycle with implications for the ability of forest soils to sequester carbon, whilst the occurrence of potentially toxic OCls in groundwater aquifers is of concern with regard to water quality. It is thus important to understand the biogeochemical cycle of chlorine, both inorganic and organic, to get information about the relevant processes in the forest ecosystem and the effects on these from human activities, including forestry practices. A survey is given of processes in the soil of temperate and boreal forests, predominantly in Europe, including the participation of chlorine, and gaps in knowledge and the need for further work are discussed. Results  Chlorine is present as chloride ion and/or OCls in all compartments of temperate and boreal forest ecosystems. It contributes to the degradation of SOM, thus also affecting carbon sequestration in the forest soil. The most important source of chloride to coastal forest ecosystems is sea salt deposition, and volcanoes and coal burning can also be important sources. Locally, de-icing salt can be an important chloride input near major roads. In addition, anthropogenic sources of OCls are manifold. However, results also indicate the formation of chlorinated organics by microorganisms as an important source, together with natural abiotic formation. In fact, the soil pool of OCls seems to be a result of the balance between chlorination and degradation processes. Ecologically, organochlorines may function as antibiotics, signal substances and energy equivalents, in descending order of significance. Forest management practices can affect the chlorine cycle, although little is at present known about how. Discussion  The present data on the apparently considerable size of the pool of OCls indicate its importance for the functioning of the forest soil system and its stability, but factors controlling their formation, degradation and transport are not clearly understood. It would be useful to estimate the significance and rates of key processes to be able to judge the importance of OCls in SOM and litter degradation. Effects of forest management processes affecting SOM and chloride deposition are likely to affect OCls as well. Further standardisation and harmonisation of sampling and analytical procedures is necessary. Conclusions and perspectives  More work is necessary in order to understand and, if necessary, develop strategies for mitigating the environmental impact of OCls in temperate and boreal forest soils. This includes both intensified research, especially to understand the key processes of formation and degradation of chlorinated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on OCls, as management can be used to produce desired effects.     

Biodegradation potential of the genus Rhodococcus

A large number of aromatic compounds and organic nitriles, the two groups of compounds covered in this review, are intermediates, products, by-products or waste products of the chemical and pharmaceutical industries, agriculture and the processing of fossil fuels. The majority of these synthetic substances (xenobiotics) are toxic and their release and accumulation in the environment pose a serious threat to living organisms. Bioremediation using various bacterial strains of the genus Rhodococcus has proved to be a promising option for the clean-up of polluted sites. The large genomes of rhodococci, their redundant and versatile catabolic pathways, their ability to uptake and metabolize hydrophobic compounds, to form biofilms, to persist in adverse conditions and the availability of recently developed tools for genetic engineering in rhodococci make them suitable industrial microorganisms for biotransformations and the biodegradation of many organic compounds. The peripheral and central catabolic pathways in rhodococci are characterized for each type of aromatics (hydrocarbons, phenols, halogenated, nitroaromatic, and heterocyclic compounds) in this review. Pathways involved in the hydrolysis of nitrile pollutants (aliphatic nitriles, benzonitrile analogues) and the corresponding enzymes (nitrilase, nitrile hydratase) are described in detail. Examples of regulatory mechanisms for the expression of the catabolic genes are given. The strains that efficiently degrade the compounds in question are highlighted and examples of their use in biodegradation processes are presented.     

Chloride concentration affects soil microbial community

We studied the effect of increased inorganic chloride concentration on forest soil microflora in a laboratory experiment. Microbial DNA extracted from experimental soil samples was amplified with PCR using primer pairs specifically amplifying bacterial, eukaryotic and fungal DNA fragments. The resulting amplified DNA was further used for terminal restriction fragment length polymorphism (TRFLP) analysis. Our work revealed that chloride concentration affects the indigenous microbial community in experimental soil. This was documented on an unidentified microorganism whose DNA was detectable in soil high in chloride but was not found in soil with low chloride concentration. The presence of the organism responsive to increased chloride concentration was associated with the highest observed value of chlorination of humic acid, suggesting possible role of this organism in soil chlorine turnover. High chloride concentration in the soil tended to decrease the rate of degradation of trichloroacetic acid. The problems connected with measurement of chlorination rates in soil are discussed.     

Ex situ bioremediation of a soil contaminated by mazut (heavy residual fuel oil)--a field experiment

Mazut (heavy residual fuel oil)-polluted soil was exposed to bioremediation in an ex situ field-scale (600 m(3)) study. Re-inoculation was performed periodically with biomasses of microbial consortia isolated from the mazut-contaminated soil. Biostimulation was conducted by adding nutritional elements (N, P and K). The biopile (depth 0.4m) was comprised of mechanically mixed polluted soil with softwood sawdust and crude river sand. Aeration was improved by systematic mixing. The biopile was protected from direct external influences by a polyethylene cover. Part (10 m(3)) of the material prepared for bioremediation was set aside uninoculated, and maintained as an untreated control pile (CP). Biostimulation and re-inoculation with zymogenous microorganisms increased the number of hydrocarbon degraders after 50 d by more than 20 times in the treated soil. During the 5 months, the total petroleum hydrocarbon (TPH) content of the contaminated soil was reduced to 6% of the initial value, from 5.2 to 0.3 g kg(-1) dry matter, while TPH reduced to only 90% of the initial value in the CP. After 150 d there were 96%, 97% and 83% reductions for the aliphatic, aromatic, and nitrogen-sulphur-oxygen and asphaltene fractions, respectively. The isoprenoids, pristane and phytane, were more than 55% biodegraded, which indicated that they are not suitable biomarkers for following bioremediation. According to the available data, this is the first field-scale study of the bioremediation of mazut and mazut sediment-polluted soil, and the efficiency achieved was far above that described in the literature to date for heavy fuel oil.     

The effect of bee pollen on secretion activity, markers of proliferation and apoptosis of porcine ovarian granulosa cells in vitro

The general objective of this in vitro study was to examine the effect of bee pollen on the release of insulin-like growth factor I (IGF-I) and steroid hormone progesterone, and expression of markers of proliferation (PCNA) and apoptosis (caspase-3) in porcine ovarian granulosa cells. Concentrations of IGF-I and progesterone were determined by RIA method and expression of PCNA and caspase-3 by immunocytochemistry. Bee pollen addition at the dose of 10 ng/mL significantly (P<0.05) inhibited IGF-I release by porcine ovarian granulosa cells. This growth factor was not influenced by 100 and 1000 ng/mL doses of bee pollen. Progesterone release by cells was not influenced by bee pollen addition at the doses of 10, 100 and 1000 ng/mL as used in our study. Similarly expression of PCNA and caspase-3 was not affected by bee pollen addition. The present study shows dose-dependent regulation of IGF-I by experimental bee pollen addition in vitro. Progesterone release, expression of PCNA and caspase-3 in porcine ovarian granulosa cells was not induced by pollen. Our results contribute to new insights regarding the possible effect of bee pollen on IGF-I release, which is important for regulation of porcine ovarian functions.     

Sediment contact test with <Emphasis Type="Italic">Potamopyrgus antipodarum</Emphasis> in effect-directed analyses—challenges and opportunities

Background and scope  

Effect-directed analysis is increasingly used for the identification of key toxicants in environmental samples and there is a growing need for in vivo biotests as diagnostic tools. Within this study, we performed an in vivo sediment contact test, applicable on both native field samples and their extracts or fractions, in order to be able to compare the results from both field and laboratory studies.     

Uptake,translocation and fate of trichloroacetic acid in a Norway spruce/soil system

Trichloroacetic acid (TCA) is a secondary atmospheric pollutant formed by photooxidation of chlorinated solvents in the troposphere--it has, however, recently been ranked among natural organohalogens. Its herbicidal properties might be one of the factors adversely affecting forest health. TCA accumulates rapidly in conifer needles and influences the detoxification capacity in the trees. The aim of the investigations--a survey of which is briefly given here--was to elucidate the uptake, distribution and fate of TCA in Norway spruce. For this purpose young nursery-grown plants of Norway spruce (Picea abies (L.) Karst.) were exposed to [1,2-14C]TCA and the fate of the compound was followed in needles, wood, roots, soil and air with appropriate radio-indicator methods. As shown by radioactivity monitoring, the uptake of TCA from soil by roots proceeded most rapidly into current needles at the beginning of the TCA treatment and was redistributed at later dates so that TCA content in older needles increased. The only product of TCA metabolism/biodegradation found in the plant/soil-system was CO(2) (and corresponding assimilates). TCA biodegradation in soil depends on TCA concentration, soil humidity and other factors.