We investigated for the first time the occurrence, stability and antibiotic resistance of 593 enterococci in six samples collected from three urban sewage treatment plants (STPs) located in the north, south and west part of Tehran, Iran between October 2004 and September of 2005. Isolates were typed with a biochemical fingerprinting method (the PhPlate system) and tested for their resistance to six antibiotics. The most prevalent species in all three STPs were E. faecium followed by E. hirae and E. faecalis accounting for 93% of the total isolates examined. In all, 317 (55%) isolates were susceptible to all six antibiotics tested and the remaining isolates were resistant to between 1 and 6 antibiotics. Biochemical fingerprinting with PhPlate system showed a high diversity for E. faecalis (D i = 0.95), E. hirae (D i = 0.93) and E. faecium (D i = 0.95) populations with an overall diversity of D i = 0.97 for the whole enterococcal populations found in all three STPs. Our data indicate a high degree of polyclonality among the enterococci populations of human origin. This study suggest that the municipal wastewaters might be an important source of dissemination of antibiotic-resistant enterococci in Iran.

This study conducted a two-stage experiment. The first stage attempted to establish biostable filter beds. Two parameters, total bacterial count (TBC) and non-purgeable dissolved carbon (NPDOC), measured by passing through a 0.2 μm membrane filter, were selected to compare the difference of biostability of a filtration system with recirculation with different O₃-to-NPDOC ratios of filtered water. The excitation emission fluorescence matrix (EEFM) was used as an effective tool for understanding information regarding organic characteristics by comparing source filtered water before and after ozonation and the effluent during biostablizing filter. During the second stage, a biostable filter was used to compare differences in biodegradability of ozonated products sodium oxalate and sodium acetate. Experimental results demonstrate that both parameters, NPDOC removal and TBC, can be utilized to evaluate the biostabilty of a filter bed. With each parameter, a plateau was reached in roughly 20 days. The source water from Chen Ching Lake (CCL) contained a protein-like substance determined by the EEFM. This protein-like substance was also destroyed by O₃/NPDOC = 1.1. Soluble microbial products (SMPs) released from the biostablizing filter into the effluent have two peaks in the EEFM, identified as protein-like and humic-like acid. The NPDOC removal for the biostabilizing filter using O₃/NPDOC = 1.7 was less than that using O₃/NPDOC = 1.1. Bacterial counts in the effluent from the biostabilizing filter using O₃/NPDOC = 1.1 was better than that of O₃/NPDOC = 1.7. This difference can be explained by the high ratio of O₃/NPDOC producing by-products of ozonation that were easily utilized by microorganisms; however, filter bed also released relatively more SMPs owing to increased proliferation of microorganisms attached to glass pellets in the filter. Regarding the differences in decomposition of the by-products of ozonation by the biostable filter, such as sodium oxalate, the NPDOC removal at O₃/NPDOC = 1.1 was better than that at O₃/DOC = 1.7. This phenomenon can be explained as previously mentioned.

Scats of the European otter (Lutra lutra) were sampled along the Allier river (France) catchment for organochlorine toxic compounds (nine pesticides and 16 PCBs congeners) measurement. From early 2004 to June 2005, 90 sites of 40 rivers were twice investigated, and 71 scats samples collected, in four geographical areas being naturally re-colonized by the species since its legal protection. Detectable pesticides and PCBs were found in 100% of the samples. Mean values reached 2.72 and 13.58 mg kg-¹ (lipid weight) for pesticides and PCBs, respectively. Amounts were significantly different between the four areas investigated. A significant increase in medium and absolute values is noted by going downstream of the catchment. Potential medium- and long-term consequences on the observed population increase are discussed.

Manganese (Mn) contamination of drinking water may cause aesthetic and human health problems when concentrations exceed 50 and 500 μg l⁻¹, respectively. In the UK, the majority of Mn-related drinking water supply failures originate from unpolluted upland catchments. The source of Mn is therefore soil, but the exact mechanisms by which it is mobilised into surface waters remain unknown. Elevated Mn concentrations in surface waters have been associated with the rewetting of dried upland soils and with conifer afforestation. We investigated these hypotheses in a laboratory experiment involving the drying and rewetting of intact soil cores (1,900 cm³ volume) of horizons of four representative soil type-land use combinations from an upland water supply catchment in southwest Scotland. Although no statistically significant effect of land use or soil type was detected on Mn concentrations in soil water, Mn release occurred from three soil horizons upon rewetting. Soil water Mn concentrations in the moorland histosol H2 (10–30 cm), the histic podzol H and Eh horizons increased from means of 5.8, 6.2 and 0.6 μg l⁻¹ prior to rewetting to maxima of 90, 76 and 174 μg l⁻¹ after rewetting, respectively. The properties of these three horizons indicate that Mn release is favoured from soil horizons containing a mixture of organic and mineral material. Mineral material provides a source of Mn, but relatively high soil organic matter content is required to facilitate mobilisation. The results can be used alongside soil information to identify catchments at risk of elevated Mn concentrations in water supplies.

Surface water is frequently contaminated by the trace metals, in particular lead and zinc, produced by mining activities. The infiltration of this water is likely to pollute surface soils and ground water. The study of the transfer of trace elements, especially lead, under real conditions is difficult to carry out due to the physicochemical and hydrodynamic complexity of real soil (preferential flows, conditions of unsaturation...), of the presence of colloids and of many candidate elements. The objective of the present study was to gain a better understanding of the parameters influencing the migration processes of trace elements in simplified systems; it was based on the study of Pb transfer in laboratory columns filled with soil. The results showed that retention of lead in soil is strongly dependent on feed flow rate, particulate bed tortuosity, bed height, water-soil surface contact and volume of water. Increase in bed height, water-soil surface contact and particulate bed tortuosity leads to higher contact time thus higher lead retention by soil, whereas increase in feed flow rate and volume of water leads to lower contact time thus lower lead retention by soil.

The prevalence and diversity of antibiotic resistant enterococci populations in samples collected four times from urban sewage treatment plant in Tehran, Iran between June 2005 and July 2006 were studied. Filtered samples were grown on mEnterococci medium containing 4 μg/ml vancomycin after which the enterococci isolates were identified to the species level. All strains were then tested for their resistance against nine antibiotics. Of the 131 isolates, 98 (75%) isolates were identified as Enterococcus gallinarum, followed by 24 (18%) and 9 (7%) for E. faecium and E. casseliflavus, respectively. All E. gallinarum isolates carried vanC1 gene with 64 (65%) and 14 (14%) isolates concomitantly harboured either vanA or vanB gene, respectively. Some E. casseliflavus concomitantly harboured vanA and vanC2 or vanB and vanC2. Typing the total enterococci isolates with a high resolution biochemical fingerprinting method showed a high diversity (D i = 0.91). We have shown by biochemical fingerprinting the presence of highly diverse glycopeptide resistant E. gallinarum and E. casseliflavus that have captured vanA and vanB genetic determinants under natural conditions. To our knowledge this is the first report in this geographical region showing high frequency antibiotic resistant enterococcal populations in particular E. gallinarum carrying assorted vancomycin resistance genes.

The aim of this study is to determine the solubility rate of tantalum contained in pyrochlore, columbite-tantalite and columbite in simulant lung fluid. The International Commission on Radiological Protection (ICRP), in its recommendation for limiting intakes of radionuclide by workers, has consistently recognized that the biological behavior of any specific material after incorporation can significantly diverge from model prevision. Model parameters should be adjusted to adapt the model for each specific substance material in order to estimate the dose due to this element intake. The most recent ICRP publication 66, respiratory tract dosimetry model, point out that information as data like particle size, aerosols solubility and the material chemical compounds are important parameters in the dose coefficients calculation. This paper studies the solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles. For this study 3 minerals were selected: pyrochlore, columbite-tantalite and columbite. Tantalum dissolution in vitro samples were obtained using the Gamble solution and PIXE (Particle Induced X-ray Emission) as analytical technique. In order to characterize the worker exposure to Ta bearing particles, one Brazilian niobium mine was selected. The mineral dust particles were collected using a six-stage cascade impactor and the elemental mass concentrations and the MMAD (Mass Median Aerodynamic Diameter) were determined. Concentrations of radionuclides from natural series of thorium and uranium were also determined. The results show that the workers are exposed to Ta bearing particles in the respirable fraction of aerosols (aerodynamic diameter (d aer) <2.5 μm) during the mineral processing to obtain Fe-Nb alloy. The solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles depends on the mineral characteristics. The solubility half-time varies between 34 and 62 h depending on the associated mineral.

Sewage sludge is a cost-effective media for the production of Bacillus thuringiensis (Bt) based biopesticides. To enhance the entomotoxicity of the fermentation broth, pretreatments of sewage sludge by alkali and ultrasonic were applied in this study. Effects of alkaline and ultrasonic pretreatments on the soluble COD (SCOD) and total COD (TCOD) were evaluated by altering the alkali addition dose and the ultrasonic specific energy. Suitable pretreatment conditions were optimized with 5 g l-¹ sodium hydroxide (NaOH) for alkaline treatment and 1.2 x 10⁵ kJ kg-¹ of total solid for ultrasonic treatment. Fermentations of raw and pretreated sludge for biopesticides were carried out in a bench scale fermentor. Results revealed that both pretreatments were effective for Bt growth and metabolism. Higher viable cells (VC) and viable spores (VS) counts, δ-endotoxin yields and entomotoxicity were achieved in the pretreated sludge. The enhancement was attributed to more available nutrients and better oxygen transfer. Moreover, ultrasonic pretreated sludge was superior to alkaline pretreated sludge for δ-endotoxin production and entomotoxicity owing to its higher soluble C/N ratio and finer particles.

We studied the seasonal cycle of the coupling between atmospheric denoxification processes and in-situ daytime formation of gas phase HNO₃ using a photochemical air pollution model. The model is constrained with urban atmospheric boundary layer observations of O₃, NO₂ and NO made in Ciudad Real, central Spain. The highest daytime HNO₃ mixing ratio of 0.3 ppbv was predicted to occur in summer, following a modelled OH concentration peak of ∼1.4 × 10⁶ molecules cm⁻³ and subsequent reaction with NO₂. During winter, calculated values of HNO₃ are lower due to less incoming radiation and higher wet removal of atmospheric HNO₃. The predicted mixing ratios are in good agreement with observations of atmospheric HNO₃ at similar urban environments in central Spain. Additionally, a marked seasonal cycle is predicted with minimum HNO₃ concentrations occurring in winter, indicative that traffic emissions and photochemistry dominate the in-situ formation of gas phase HNO₃ at this location. This process has implications in the removal of NOₓ from the urban atmosphere.