Polycyclic aromatic hydrocarbons (PAHs) in soils of the Moscow Region--concentrations, temporal trends, and small-scale distribution

The knowledge of the environmental fate of polycyclic aromatic hydrocarbons (PAHs) is restricted to few climatic regions of the world almost excluding the Taiga. Our objectives were to (i) separate anthropogenic from background contributions to PAH concentrations and (ii) determine temporal trends in PAH concentrations during the last century including the change in distribution of PAHs in interior and exterior portions of aggregates in soils of the Moscow region. Along a southeast-bound transect from Moscow (windward in winter) and at a background location northeast of Moscow (leeward in winter), seven topsoil samples were collected in 1910-1954 and 35 in 1998-2003. We fractionated the soils in interior and exterior portions of aggregates > 10 mm and remaining soil without aggregates. The sum of 21 PAHs (sigma21PAHs) concentrations in recent bulk soil ranged from 59 to 1350 ng g(-1). The concentrations of all PAHs were lower outside than in Moscow. The range of the concentrations of the sigma21PAHs in archived soil samples (159-1280 ng g(-1)) was similar as in recent soils. In most recent and archived samples, naphthalene and phenanthrene, were most abundant. The concentrations of low-molecular-weight PAHs decreased during the last century at most sites; those of high-molecular-weight compounds increased. The sigma21PAHs concentrations were accumulated in the exterior of aggregates (109%) and depleted in the interior (95%) relative to the concentration in bulk soil (defined as 100%), which was similar to that in the soil without aggregates (99%). The differences between aggregate interior and exterior did not change during the last century. The dominance of naphthalene and phenanthrene is typical of remote regions. The urban influence on PAH concentrations in the last century was small.     

Bioproduction of ferric sulfate used during heavy metals removal from sewage sludge

Toxic metals removal from wastewater sewage sludge can be achieved through microbial processes involving Acidithiobacillus ferrooxidans. The oxidation of ferrous ions by A. ferrooxidans, cultured in sewage sludge filtrate, was studied in both batch and continuous flow stirred tank reactors. Sewage sludge filtrate containing natural nutrients (phosphorus and nitrogen) was recovered as effluent following the dehydration of a primary and secondary sludge mixture. Batch and continuous flow stirred tank reactor tests demonstrated that A. ferrooxidans were able to grow and completely oxidize ferrous iron in a culture medium containing more than 80% (v v(-1)) sewage sludge filtrate with 10 g Fe(II) L(-1) added. Toxic levels were reached when total organic carbon in the sewage sludge filtrate exceeded 250 mg L(-1). The ferric iron solution produced in the sludge filtrate by A. ferrooxidans was used to solubilize heavy metals in primary and secondary sludge. The solubilization of Cu, Cr, and Zn yielded 71, 49, and 80%, respectively. This is comparable with the yield percentages obtained using a FeCl(3) solution. The cost of treating wastewater sewage sludge by bioproducing a ferric ion solution from sewage sludge is three times less expensive than the conventional method requiring a commercial ferric chloride solution.     

Status and fuzzy comprehensive assessment of combined heavy metal and organo-chlorine pesticide pollution in the Taihu Lake region of China

The status of combined heavy metal and organo-chlorine pesticide (OCPs; i.e. HCH and DDT) pollution was investigated and the soil environmental quality of the Taihu Lake watershed, one of the most developed regions in China, was evaluated using a fuzzy comprehensive assessment. Statistical analyses showed the presence of combined pollution in the soil. At many sampling sites, heavy metal concentrations were above corresponding background values, indicating the effects of extraneous pollutants. It has been over 20 years since China banned the use of OCPs, but they can still be found in soil samples of this region. HCH levels at all investigated sites were below the Chinese Environmental Quality Standard for Soils. Fuzzy comprehensive assessment showed that the overall soil quality in this region could be categorized as class I. Nevertheless, the high coefficients of variation for levels of DDT, Cd and Hg indicated the existence of some point-source pollution. Continuous monitoring and further studies of the region are recommended to prevent pollution of farmland from these sources.     

Improvement of the BCR three step sequential extraction procedure prior to the certification of new sediment and soil reference materials

The Standards, Measurements and Testing Programme (formerly BCR) of the European Commission proposed a three-step sequential extraction procedure for sediment analysis, following extensive expert consultations and two interlaboratory studies. This scheme was recently used to certify the extractable trace element contents of a sediment reference material (CRM 601). Although this procedure offers a means to ensure the comparability of data in this field, some difficulties concerning the interlaboratory reproducibility still remain, and a new project is currently being conducted to determine the causes of poor reproducibility in the extraction scheme. The final objective of the project is the certification of new sediment and soil reference materials for their extractable contents of Cd, Cr, Cu, Ni, Pb and Zn. This paper presents the results of a small-scale interlaboratory study, which aimed to test a revised version of the extraction schemes by comparing the original and the modified protocols using the CRM 601 sample. This work offers an improvement to the BCR sequential extraction procedure through intercomparison exercises. This improved procedure will allow the obtaining of CRMs to validate analytical data in the analysis of soils and sediments, and it will also facilitate comparability of data in the European Union.     

Distribution, accumulation and mobility of mercury in superficial sediment samples from Tianjin, northern China

Seventeen sediment samples at three representative sites (the Yuqiao Reservoir, the Haihe River and the Haihe River Estuary) in Tianjin, northern China, were analyzed to investigate the pollution status, accumulation and mobility of mercury (Hg). The results show that the Haihe River has to be considered as moderate to strongly contaminated with Hg (2 < mean I(geo) = 2.35 < 3), where total Hg contents were ca. 3 to 24 orders of magnitude greater than the regional background value. The sediments collected near a coal-fired power plant in an urban area were found to have very high Hg concentrations, which were significantly related to Hg emissions from coal-fired utility boilers. In the Yuqiao Reservoir, the surface sediments have to be considered as unpolluted with Hg (mean I(geo) = -0.05 < 0) and the Haihe River Estuary sediments have to be considered as unpolluted to moderately polluted with Hg (0 < mean I(geo) = 0.18 < 1). Sediment-bound Hg in the Yuqiao Reservoir and the Haihe River Estuary was found to be predominantly associated with the organo-chelated phase of the sediment (38.3% and 50.5%, respectively). However, unlike the Yuqiao Reservoir and the Haihe River Estuary, Hg in the Haihe River sediments existed mainly as sulfide Hg and elemental Hg, which accounted for 54.2% and 30.7% of total Hg, respectively. The availability of this element seemed restricted. The majority of Hg contamination in the Haihe River sediments had been attributed to historic and modern atmospheric deposition and Hg released from the Haihe River sediments didn't seem to be an important pollutant pathway into the Haihe River Estuary. The results provide new insights into Hg contamination in this region.     

Integrated biomarker response index as a useful tool for environmental assessment evaluated using transplanted mussels

Mytilus galloprovincialis mussels from a clean area were transplanted from 2003 to 2005 to several stations in the Bay of Cannes (North-Western Mediterranean Sea) including a site considered as reference, for 1 month at the end of spring (May). Several biomarkers (AChE, GST and CAT activities, TBARS and MT concentrations) were measured in the transplanted organisms. The concentrations of metals (Cd, Cu and Zn) were determined in the transplanted mussels, PAH and PCB analyses were performed in the mussels caged in 2004. The integrated biomarker response (IBR) was calculated; pollutant concentrations in mussels were displayed as star plots and compared to IBR star plots. Visualization was thus possible between sites for comparison with exposure conditions. Results demonstrated that the mussels from the Old harbour site (VP) are characterized by elevated copper and PCB concentrations, those from Canto harbour (PC) presented high PCB contents and those from the mouth of the Siagne River (ES) high PAH concentrations compared to the animals transplanted in the reference site (IL). In 2003, there was a visual correlation between the copper gradient measured in the transplanted mussels and the IBR variation. In 2004, the agreement between the copper gradient and the PCB gradient measured in the caged mussels and the IBR variation was good whereas the PAH gradient did not seem to contribute to the IBR demonstrating that the chosen biomarkers did not respond to PAHs. In 2005, IBR showed that other contaminants, not measured might be present in VP, PC and ES compared to the reference station (IL).     

Potassium carbonate-based ternary transition temperature mixture (deep eutectic analogues) for CO2 absorption: Characterizations and DFT analysis

•Addition of hindered amine increased thermal stability and viscosity of TTTM. •Addition of hindered amine improved the CO₂ absorption performance of TTTM. •Good the CO₂ absorption of recycled solvents after two regenerations. •Important role of amine group in CO₂ absorption of TTTM confirmed by DFT analysis. Is it possible to improve CO₂ solubility in potassium carbonate (K₂CO₃)-based transition temperature mixtures (TTMs)? To assess this possibility, a ternary transition-temperature mixture (TTTM) was prepared by using a hindered amine, 2-amino-2-methyl-1,3-propanediol (AMPD). Fourier transform infrared spectroscopy (FT-IR) was employed to detect the functional groups including hydroxyl, amine, carbonate ion, and aliphatic functional groups in the prepared solvents. From thermogravimetric analysis (TGA), it was found that the addition of AMPD to the binary mixture can increase the thermal stability of TTTM. The viscosity findings showed that TTTM has a higher viscosity than TTM while their difference was decreased by increasing temperature. In addition, Eyring’s absolute rate theory was used to compute the activation parameters (ΔG*, ΔH*, and ΔS*). The CO₂ solubility in liquids was measured at a temperature of 303.15 K and pressures up to 1.8 MPa. The results disclosed that the CO₂ solubility of TTTM was improved by the addition of AMPD. At the pressure of about 1.8 MPa, the CO₂ mole fractions of TTM and TTTM were 0.1697 and 0.2022, respectively. To confirm the experimental data, density functional theory (DFT) was employed. From the DFT analysis, it was found that the TTTM+ CO₂ system has higher interaction energy (|ΔE |) than the TTM+ CO₂ system indicating the higher CO₂ affinity of the former system. This study might help scientists to better understand and to improve CO₂ solubility in these types of solvents by choosing a suitable amine as HBD and finding the best combination of HBA and HBD.     

Occurrence of PAHs, PCBs and organochlorine pesticides in the Tonghui River of Beijing, China

Tonghui River, a typical river in Beijing, People's Republic of China, was studied for its water and sediment quality, by determining the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides in water and sediment samples. Total PAHs, PCBs and organochlorine pesticides concentrations in water varied from 192.5 to 2651 ng/l, 31.58-344.9 ng/l and 134.9-3788 ng/l, respectively. The total PAHs, PCBs and organochlorine pesticides concentrations in surficial sediments were 127-928 ng/g, 0.78-8.47 ng/g and 1.79-13.98 ng/g dry weight, respectively. The results showed that the concentration of these selected organic pollutants in sediment was higher than those in surface water. It may be due to the fact that organic hydrophobic pollutants tend to stay in the sediments. The PAHs were dominated by 2-, 3-ring components in water samples and by 3- and 4-ring compounds in sediment. For organochlorines, alpha-HCH, delta-HCH, Heptachlor, Endosulfan II, DDT are the major organochlorine pesticides in water while Heptachlor, Dieldrin and DDE composed of 95% of total organochlorine pesticides in sediment. For HCHs (HCHs=alpha-HCH+beta-HCH+gamma-HCH+delta-HCH), the predominance of alpha-HCH of total HCHs were clearly observed in water and sediment. PCB18, PCB31 and PCB52 were predominant in water, on average these compounds collectively accounted for 67% of total PCBs. But in sediment, the predominant compounds were PCB28, PCB31 and PCB153, which accounted for 71% of total PCBs in sediment. The levels of micro pollutants in our study areas were compared with other studies.     

Xenoestrogens in the River Elbe and its tributaries

4-Alkylphenols, 4-alkylphenol ethoxylates, 4-alkylphenoxy carboxylates, bisphenol A, bisphenol F, 4-hydroxyacetophenon, 4-hydroxybenzoic acid and steroid hormones were analyzed in water samples of the River Elbe and its tributaries Schwarze Elster, Mulde, Saale, Havel and Schwinge. Additionally, freshly deposited sediments (FDS, composite samples) of the River Elbe and its tributaries were analyzed. The concentrations in water samples ranged from (in ng/l): bisphenol A 4 to 92, branched nonylphenol 13 to 87, branched nonylphenol ethoxylates <0.5 to 120, 4-tert. nonylphenoxy carboxylates <10 to 940 and 4-hydroxybenzoic acid 4 to 12. Steroid hormones were only detected in the Czech tributaries Jizera and Vltava in concentrations near the limit of quantification. In FDS samples the concentrations amounted to (in g/kg d.w.): bisphenol A 10-380, branched nonylphenol 27-430, branched nonylphenol ethoxylates 24-3700, nonylphenoxy carboxylates <50 and 4-hydroxybenzoic acid 23-4400. Increased bisphenol A concentrations were found in water and FDS samples taken from the Czech-German border at Schmilka and the mouth of the Schwinge (only water sample). According to studies conducted in the Elbe Estuary and the German Bight, the River Elbe must be considered as a major source of pollution for the North Sea in respect of the compounds analyzed. A comparison of bisphenol A concentrations, 4-alkylphenols and the corresponding ethoxylates analyzed in the River Elbe and its tributaries with those found in other German surface waters indicated a low level of contamination. The evaluation of the data based on LOEC-values indicated that the concentrations were well below the effectivity threshold for some 4-alkylphenols. According to recent ecotoxicological investigations, for example, with prosobranch snails, bisphenol A concentrations found in water samples of the River Elbe and its tributaries may well be detrimental to aquatic organisms. On the basis of the monitoring data and its implications for estrogenic potency the inclusion of bisphenol A in the list of priority substances (European Union Directive 2000/60/EC, Annex X) should be considered.     

Estimation and characterization of PCDD/Fs and dioxin-like PCBs from Chinese iron foundries

The iron foundry industry is considered to be a potential source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study investigated the emission factors and total emission amounts of PCDD/Fs and dioxin-like polychlorinated biphenyls (DL-PCBs) from iron foundries in China. The concentrations and the World Health Organization toxicity equivalents (WHO-TEQs) are presented and the congener profiles are discussed in this paper.In the present work, 26 fly ash samples were collected and tested to quantify the PCDD/Fs and DL-PCBs generated by 14 plants of different scales, and five stack gas samples were collected from two (named as EFG and LFG) of those plants. The emission levels of PCDD/Fs and DL-PCBs indicated that hot-air cupolas had lower emissions than cold-air cupolas. When iron ore lump and sinter were used as raw material, the emission factors were about 250 ng TEQ t⁻¹ of product. However, if the raw material was scrap, the emission factors varied owing to the different contents of organic materials in the raw materials. It was found that the mean WHO-TEQ values of PCDD/Fs and DL-PCBs were 144 and 34.2 pg Nm⁻³ in stack gas and 20.0 and 1.58 pg g⁻¹ in fly ash. In multiple tests, it was estimated that the mean emission factors of PCDD/Fs and DL-PCBs were 365 and 10.9 ng WHO-TEQ t⁻¹ released to residue and 2719 and 555 ng TEQ t⁻¹ released to air. The total emission amounts of PCDD/Fs and DL-PCBs from Chinese iron foundries with cupola furnaces released to residue and air were 16.8 and 146 g WHO-TEQ in 2008, respectively.