BACKGROUND, AIM AND SCOPE: Metal pollution is a serious problem for environmental safety and programmes of monitoring and bioremediation are needed. Among the processes of bioremediation, the use of microbes to remove and degrade contaminants is considered a biotechnological approach to clean up polluted environments. AIM: The aim of this study was to evaluate the ability of Serratia marcescens in Pb, Cd and Cr removal and the potential use of these bacteria in toxic metal bioremediation from polluted environments. METHODS: A short-term study (120 min) was carried out to study the bacterial growth in the presence of sub-inhibitory concentrations of each metal analysed and the kinetics of metal biosorption in S. marcescens strain. In addition, metal influence on the biosynthesis of the red pigment ‘prodigiosina’ by S. marcescens was monitored. RESULTS: The results obtained in this study show metals biosorption by S. marcescens (range: 0.0133–0.213 μg/g for Pb; 0.097–0.1853 μg/g for Cd; and 0.105–0.176 μg/g for Cr) and confirm the possible use of this bacterium to realize bioremediation processes, especially for Pb removal, and as a bioindicator of metal pollution.

PURPOSE: Various publications indicate that the operation of laser printers and photocopiers may be associated with health effects due to the release of gaseous components and fine and ultrafine particles (UFP). However, only sparse studies are available that evaluate the possible exposure of office workers to printer emissions under real conditions. Therefore, the aim of our study was to assess the exposure of office workers to particulate matter released from laser printers and photocopiers. METHODS: Concentrations of fine particles and UFP were measured before, during, and after the operation of laser printing devices in 63 office rooms throughout Germany. Additionally, the particles were characterized by electron microscopy and energy-dispersive X-ray spectroscopy. RESULTS: A significant increase of fine particles and UFP was identified in ambient workplace air during and after the printing processes. Particle fractions between 0.23 and 20 μm emitted by the office machines significantly affect particle mass concentrations while printing 500 pages, i.e., during the printing process, PM0.23–20, PM2.5, and PM10 concentrations increased in 43 out of the evaluated 62 office rooms investigated. Additionally, a significant increase was observed in submicrometer particles, with median particle number concentrations of 6,503 particles/cm3 before and 18,060 particles/cm3 during the printing process. CONCLUSIONS: Our data indicate that laser printers and photocopiers could be a relevant source of fine particles and particularly UFP in office rooms.

PURPOSE: This study contains some new findings connected to the photolysis of the drug paracetamol (hereinafter APAP) especially in light of estimating natural conditions, and it will offer information to better evaluate environmental problems connected with this widely used analgesic agent. Only a few studies, so far, have focussed on the photodegradation process of APAP in the natural environment, and the question about the role of the colored/chromophoric dissolved organic matter (CDOM) and nitrate (NO 3 − ) as photoinductors is almost open. METHODS: APAP dissolved in freshwater and pure laboratory water in the presence and absence of CDOM and NO 3 − ions was irradiated using weak-energy photon energies simulating natural conditions. RESULTS: CDOM and NO 3 − as photoinductors produced only the slow phototransformation of APAP under weak energy radiation, and APAP seemed to be practically resistant to direct photolysis under weak radiant energies available in natural conditions. The estimated reaction efficiencies, in addition to half-lives, speak for that NO 3 − and CDOM do not act as quite independent photoinductors but their effect in conjunction (CDOM–NO 3 − –water) is stronger than the separate ones. The principal phototransformation intermediates of APAP were mono-hydroxy derivatives, depending on available photon energies formed via ortho- or meta-hydroxylation, possessing substantial power of resistance to further specific transformation reactions. CONCLUSIONS: The estimated half-life of the phototransformation of APAP in the natural aqueous environment and in the presence of suitable photoinductors will be about 30 days or more.

Perfluorooctane sulfonate (PFOS) (C₈F₁₇SO₃) and perfluorooctanoic acid (PFOA) (C₈HF₁₅O₂) are synthetic chemicals widely used in industrial applications for their hydrophobic and oleophobic properties. They are persistent, bioaccumulative, and toxic to mammalian species. Their widespread distribution on earth and contamination of human serum raised concerns about long-term side effects. They are suspected to be carcinogenic through a nongenotoxic mode of action, a mechanism supported by recent findings that PFOS induced cell transformation but no genotoxicity in Syrian hamster embryo (SHE) cells. In the present study, we evaluated carcinogenic potential of PFOA using the cell transformation assay on SHE cells. The chemical was applied alone or in combination with a nontransformant concentration of benzo[a]pyrene (BaP, 0.4 μM) in order to detect PFOA ability to act as tumor initiator or tumor promoter. The results showed that PFOA tested alone in the range 3.7 × 10⁻⁵ to 300 μM did not induce SHE cell transformation frequency in a 7-day treatment. On the other side, the combination BaP/PFOA induced cell transformation at all PFOA concentrations tested, which revealed synergistic effects. No genotoxicity of PFOA on SHE cells was detected using the comet assay after 5 and 24 h of exposure. No significant increase in DNA breakage was found in BaP-initiated cells exposed to PFOA in a 7-day treatment. The whole results showed that PFOA acts as a tumor promoter and a nongenotoxic carcinogen. Cell transformation in initiated cells was observed at concentrations equivalent to the ones found in human serum of nonoccupationally and occupationally exposed populations. An involvement of PFOA in increased incidence of cancer recorded in occupationally exposed population cannot be ruled out.

INTRODUCTION: Five liver samples of two different ray species (Gymnura altavela and Zapteryx brevirostris) off the coast of Rio de Janeiro, Brazil, were analyzed for their pollution with anthropogenic and naturally occurring organohalogen compounds. MATERIAL AND METHODS: The samples were extracted with accelerated solvent extraction, and after a clean-up procedure, organohalogen compounds were separated by a modified group separation on activated silica. Subsequent analyses were done by targeted and non-targeted gas chromatography–mass spectrometry in the electron capture negative ion mode. RESULTS AND DISCUSSION: “Classic” organohalogen compounds such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and technical 1,1,1-trichloro-2,2-di(4-chlorophenyl)ethane (DDT) were detected and quantified. PCBs generally exceeded the parts per million level and represented up to 90% of the total contamination of the ray livers. High concentrations were also detected for p,p′-DDE. Non-targeted full scan investigations lead to the detection of an abundant trichlorinated compound which was identified as a new DDT metabolite in biota. Different PBDE congeners and several halogenated natural products were quantified as well. In addition, polychlorinated terphenyls were identified and analyzed in the two species. Moreover, both ray species showed different fatty acid patterns and stable carbon isotope signatures. CONCLUSIONS: The two ray species showed high concentrations of organohalogen compounds in their liver tissue. Varied δ 13C values by up to 3.1‰ indicated that the two ray species were living in different habitats.

INTRODUCTION: This article recalls and demonstrates that heterogeneous photocatalysis belongs to heterogeneous catalysis according to its initial history. There are criteria, which have to be imperatively taken into account to deal with true (photo-)catalytic reactions. The photocatalytic activity, chosen as the reaction rate, is governed by five physical parameters (mass of catalyst, wavelength, initial concentrations (or pressures) of the reactants, temperature (around room temperature), and radiant flux). DISCUSSION: Once performed in optimal conditions, the reaction has to be characterized with (a) its quantum yield <QY> (ratio of the reaction rate to the incident photon flux), (b) the turnover number <TON> (number of molecules converted per active site during a given time), and (c) the turnover frequency <TOF> (<TON> per second). The true catalytic nature demands that the conversion provides a number of converted molecules higher than the “stoichiometric threshold” defined as the number of the active sites initially present on the catalyst, i.e., that <TON> be much greater than 1, and possibly than at least two or three orders of magnitude. Eventually, a complete mass balance determination should be established for all elements. It is shown that the main reaction intermediates are radicals. All these concepts and principles are illustrated by various examples (selective mild oxidation reactions, water pollutants elimination, and air purification), leading to a list of recommendations for performing really true catalytic reactions.

BACKGROUND AIM AND SCOPE: Though the tidal Anacostia River, a highly polluted riverine system, has been well characterized with regard to contaminants, its overall resident bacterial populations have remained largely unknown. Improving the health of this system will rely upon enhanced understanding of the diversity and functions of these communities. Bacterial DNA was extracted from archived (AR, year 2000) and fresh sediments (RE, year 2006) collected from various locations within the Anacostia River. Using a combination of metabolic and molecular techniques, community snapshots of sediment bacterial diversity and activity were produced. RESULTS: Employing Biolog EcoPlates, metabolic analysis of RE sediments from July revealed similar utilization of amines, amino acids, carbohydrates, carboxylic acids, and polymers at all sites. Normalized optical density measurements demonstrated that for most compounds, utilizations were similar though when differences did occur, the downstream site was enhanced compared to one or both of the upstream sites. Using denaturing gradient gel electrophoresis, bacterial diversity fingerprints of operational taxonomic units (OTUs) were obtained. Dendograms of the banding patterns revealed qualitative relationships as well as differences between replicate samples from similar sites. Replicates from the AR sites shared several common OTUs, while RE sites were more varied. Species richness and Shannon diversity indices generally increased with increasingly downstream locations, and were significant for the AR sediments (analysis of variance, P < 0.0001). Carbon and nitrogen content and concentration of fine grain sediment (<63 μm) were positively correlated with OTU richness (r 2 = 0.37, P = 0.0008; r 2 = 0.45, P < 0.0001; r 2 = 0.48, P = 0.001, respectively). CONCLUSIONS: This study demonstrated that the bacterial communities from all regions sampled were not only metabolically active with the capacity to utilize several different compounds as energy sources but also were genetically diverse. This study is the first to focus on the overall bacterial community, providing insight into this vital component of stream ecosystems. Understanding the bacterial components of aquatic systems such as the Anacostia River will increase our knowledge of the overall structure and function of the ecological communities in polluted systems, subsequently enhancing our ability to improve the health of this important tidal river.

Perfluorinated compounds (PFCs) are persistent and bioaccumulative organic compounds used as additives in many industrial products. After use, these compounds enter wastewater treatment plants (WWTP) and long-chain PFCs are primarily accumulated in sludge. The aim of this study was to determine the occurrence and behavior of five PFCs in sludge from 15 WWTP from Spain and Germany that receive both urban and industrial wastes. The PFCs studied were perfluorooctanesulfonate (PFOS), perfluorohexanesulfonate (PFHxS), perfluorobutanesulfonate (PFBS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA). One gram of freeze-dried, sieved, and homogenized sludge was extracted using an ultrasonic bath with methanol and glacial acetic acid. After that, the extract was recovered and evaporated to dryness with a TurboVap and then 1 mL of acetonitrile was added and the extract was cleaned up with black carbon. Liquid chromatography coupled to mass spectrometry operated in selected reaction monitoring was used to determine target compounds. Quality parameters are provided for the set of compounds studied. PFCs were detected in all samples. In Spanish sludge, ∑PFC ranged from 0.28 to 5.20 ng/g dry weight (dw) with prevalence of PFOS, while in German sludge, ∑PFC ranged from 20.7 to 38.6 ng/g dw and PFBS was the dominant compound. As a next step, the evolution of PFC concentrations within the sludge treatment steps (primary sludge, anaerobic digested sludge, and centrifuged sludge) was evaluated and differences among levels and patterns were observed and were attributed to the influent water quality and treatment used. Finally, we estimated the amount of PFCs discharged via sludge in order to determine the potential impact to the environment according to different sludge usage practices in the two regions investigated. This manuscript provided an intra-European overview of PFC distribution in sludge. Levels and compound distribution depend on the WWTP sampled. This study demonstrates that PFCs are persistent to sludge treatment and the loads in sludge may pose a future environmental risk, if not controlled.

INTRODUCTION: From December 2008 to November 2009, an investigation of water quality was performed in the 70-km long downstream from Gezhouba Dam in Yangtze River. METHODS: Twelve sites in all were chosen. Nine parameters of water quality including the total phosphorus, the total nitrogen, chlorophyll a (Chl.a), nitrite, nitrate, ammonia, water temperature, DO, and pH were monitored almost monthly. The multivariate statistical technique (cluster analysis) and the nonparametric method (Kruskal–Wallis Test and Spearman’s rank correlation) were applied to evaluate the spatiotemporal variations of water quality data sets. RESULTS AND DISCUSSION: According to the Chinese environmental quality standards for surface water (GB3838-2002), the water quality in the river section investigated can attain to the III water standards except total nitrogen. Further analysis indicated that there were no significant spatial differences in these parameters of water quality, but the sampling date had a significant effect. The temporal variation of water quality can be related to the discharge of Gezhouba Dam and moreover be affected by the reservoir regulation. During the discharge, the discharge increased the concentration of total phosphorus and then decreased the N:P ratio, which helps to the occurrence of algae blooms. The high consternation of phosphorus and the low N:P ratio show that the water body can be in the process of eutrophication during the discharge of Gezhouba Dam. In fact, Chl.a had begun to rise in the same period.

PURPOSE: This research was designed to investigate the feasibility of converting the dinitrotoluene sulfonates (DNTS) in TNT red water into the corresponding aromatic amino compounds using nanoscale zerovalent iron (NZVI). METHODS: NZVI particles were simultaneously synthesized and stabilized by sodium borohydride reduction in a nondeoxygenated system. The morphology, elemental content, specific surface area, and crystal properties of the NZVI were characterized before and after the reaction by environmental scanning electron microscope; energy dispersive X-ray; Brunauer, Emmett, and Teller; and X-ray diffraction, respectively. The reduction process was conducted at pH = 6.3 at ambient temperature. The efficiency of the NZVI-mediated DNTS reduction process was monitored by HPLC, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses. RESULTS: The properties of the NZVI particles prepared were found to be similar to those obtained through oxygen-free preparation and inert stabilization processes. Both 2,4-DNT-3-sulfonate (2,220 mg L−1) and 2,4-DNT-5-sulfonate (3,270 mg L−1) in TNT red water underwent a pseudo-first-order transformation when mixed with NZVI at room temperature and near-neutral pH. Their observed rate constants were 0.11 and 0.30 min−1, respectively. Within 1 h of processing, more than 99% of DNTS was converted by NZVI-mediated reduction into the corresponding diaminotoluene sulfonates. CONCLUSIONS: NZVI can be simultaneously prepared and stabilized in a nondeoxygenated system. NZVI reduction is a highly efficient method for the conversion of DNTS into the corresponding diaminotoluene sulfonates under near-neutral pH conditions. Therefore, NZVI reduction may be useful in the treatment of TNT red water and subsequent recovery of diaminotoluene from explosive wastewater.