Total topsoil 50th percentile Cu, Pb and Zn concentrations (n = 491) in the Sydney estuary catchment were 23 μg g−1, 60 μg g−1 and 108 μg g−1, respectively. Nine percent, 6% and 25% of samples were above soil quality guidelines, respectively and mean enrichment was 14, 35 and 29 times above background, respectively. Soils in the south-eastern region of the catchment exhibited highest metal concentrations. The close relationship between soil metal and road network distributions and outcomes of vehicular emissions modelling, strongly suggested vehicular traffic was the primary source of metals to catchment soils. Catchment soil and road dust probably make an important contribution to contamination of the adjacent estuary. The concentration of soil metals followed the land use trend: industrial > urban > undeveloped areas. A high proportion (mean 45%, 62% and 42%, for Cu, Pb and Zn, respectively) of metals in the soils may be bioavailable.

Identifying the factors responsible for the diversity of responses of biota to industrial pollution is crucial for predicting the fates of polluted ecosystems. A meta-analysis based on 49 field studies conducted around 47 point polluters demonstrated that the individual (growth and reproduction) and community (abundance and species richness) characteristics of bryophytes in polluted habitats are reduced to about a half of the values observed in unpolluted sites. Non-ferrous smelters cause a stronger reduction in species richness and larger changes in species composition than other types of polluters. The magnitudes of the effects of pollution on the abundances of individual bryophyte species are not linked with their taxonomic position, life form or Ellenberg indicator values for light, moisture and nitrogen. The variation in species’ responses to pollution is mostly explained by differences in their reproductive characteristics; bryophyte species that possess special forms of vegetative reproduction and those that produce abundant sporophytes are more successful in polluted habitats. Ranking of bryophyte species according to their sensitivity to pollution is independent of the type of the polluter. Changes in bryophyte cover follow changes in tree cover, but not changes in the cover of the vascular field layer in the same pollution gradients. Pollution impacts cause stronger adverse effects on bryophytes in warmer climates.

Non-destructive measurements of contaminated soil core samples are desirable prior to destructive measurements because they allow obtaining gross information from the core samples without touching harmful chemical species. Medical X-ray computed tomography (CT) and time-domain low-field nuclear magnetic resonance (NMR) relaxometry were applied to non-destructive measurements of sandy soil core samples from a real site contaminated with heavy oil. The medical CT visualized the spatial distribution of the bulk density averaged over the voxel of 0.31 × 0.31 × 2 mm³. The obtained CT images clearly showed an increase in the bulk density with increasing depth. Coupled analysis with in situ time-domain reflectometry logging suggests that this increase is derived from an increase in the water volume fraction of soils with depth (i.e., unsaturated to saturated transition). This was confirmed by supplementary analysis using high-resolution micro-focus X-ray CT at a resolution of ∼10 μm, which directly imaged the increase in pore water with depth. NMR transverse relaxation waveforms of protons were acquired non-destructively at 2.7 MHz by the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence. The nature of viscous petroleum molecules having short transverse relaxation times (T2) compared to water molecules enabled us to distinguish the water-saturated portion from the oil-contaminated portion in the core sample using an M ₀-T2 plot, where M ₀ is the initial amplitude of the CPMG signal. The present study demonstrates that non-destructive core measurements by medical X-ray CT and low-field NMR provide information on the groundwater saturation level and oil-contaminated intervals, which is useful for constructing an adequate plan for subsequent destructive laboratory measurements of cores.

The global cycle of mercury (Hg) is reasonably well-understood, as are some of the natural and anthropogenic sources of Hg to the atmosphere. Less well understood are the regional and local characteristics of Hg deposition and subsequent watershed-scale transport, important parameters for assessing human risk to various avenues of Hg exposure. This study employed a two-part strategy for understanding coupled deposition and transport processes in central Indiana (USA), including Indianapolis, a typical large city with multiple coal-fired electric utilities and other Hg emission sources. A spatial analysis of Hg concentrations in surface soils revealed elevated Hg proximal to many of the large emission sources, with a distribution aligned along a southwest-northeast axis corresponding to the mean wind direction in this region. This soil distribution suggests some local depositional impact from local utilities, with wind modification affecting the regional pattern. Post-depositional transport of Hg was assessed using a series of streambank sampling arrays as the White River and various tributaries travelled through the urban core of Indianapolis. Streambank sediments had peak Hg concentrations in the urban core, where several local sources are present and where a number of subwatersheds join the main trunk of the White River, suggesting local emission and/or rapid Hg transport from urban subwatersheds due to their relatively high proportion of impervious surfaces. High Hg values persist in White River sediments into rural areas tens of kilometers south of Indianapolis, raising concerns for anglers collecting fish in this apparently “pristine” environment.

Fe3+ and Ce3+ codoped titanium dioxide films with high photocatalytic activity were successfully obtained via the improved sol–gel process. The as-prepared specimens were characterized using X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (FE-SEM), X-ray energy dispersive spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray photoelectron spectroscopy, photoluminescence (PL) spectra, and UV–Vis diffuse reflectance spectroscopy. The photocatalytic activities of the films were evaluated by degradation of various organic dyes in aqueous solutions. The results of XRD, FE-SEM, and BET analyses indicated that the TiO2 film had nanostructure. With the codoping of Fe3+ and Ce3+, TiO2 photocatalysts with smaller crystal size, larger surface area, and larger pore volume were obtained. Moreover, codoped ions could obviously not only suppress the formation of brookite phase but also inhibit the transformation of anatase to rutile at high temperature. Compared with pure TiO2 film, Fe3+ doped or Ce3+ doped TiO2 film, the Fe3+/Ce3+ codoped TiO2 film exhibited excellent photocatalytic activity. It is believed that the surface microstructure of the films and the doping methods of the ions are responsible for improving the photocatalytic activity.

Over the past decades, the global production of petroleum coke, a by-product of the oil sand industry, has increased with the growing importance of oil sands as a source of fossil fuels. A greenhouse study using Triticum aestivum and Deschampsia caespitosa was conducted to assess the growth and physiological effects of coke on plants. The plants were grown in cokes with or without a cap of peat–mineral mix and were compared to plants grown in a peat–mineral mix (control). Our results indicate that the selected plants can survive in coke; however, stress symptoms such as reductions in transpiration (45–91%) and stomatal conductance rates (44–92%) in T. aestivum, biomass in T. aestivum (5–83%) and D. caespitosa (43–90%), photosynthetic pigments in T. aestivum (32–68%) and D. caespitosa (33–44%) and proline concentrations in D. caespitosa (77–97%) were observed. Furthermore, potentially phytotoxic concentrations of nickel (47–69 μg g−1 in D. caespitosa) and vanadium (9.3–18.3 μg g−1 in T. aestivum and 4–27.8 μg g−1 in D. caespitosa) were found in some tissues while molybdenum accumulated in D. caespitosa shoots at concentrations reported, in other studies, to cause molybdenosis in ruminants. These results suggest that the plants growing in coke could experience multiple stresses including water stress, nutrient deficiencies and/or Ni and V toxicity. Capping coke with peat–mineral mix limited the stress symptoms and could improve revegetation success of coke impoundment sites. This study provides baseline data for future long-term field studies essential for developing coke management guidelines.

The assessment of metals dispersal in polluted mining areas is a very complex issue, usually needing data from several analytical techniques in a joint approach. The present work focuses on the impact of the mining activity on lowlands alluvial plain sediments from an ephemeral creek, their role as source or sink of pollution and the spatial distribution of metals within the zone. In-depth distribution of elements (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, S, Ti and Zn) coming from mining activities was investigated by using X-ray fluorescence techniques and their mineralogical form using X-ray diffraction. A 2-D electrical resistance tomography field survey was carried out throughout at the creek bed to interpret the potential relationships between chemical, mineralogical and geophysical parameters. The application of leaching procedure (DIN 38414-S4 test) allows us to know the sediment’s heavy metals hazard and their potential mobility when changing redox conditions. From the results it was found that redox process of sulphur and the presence of carbonate influence the distribution of metals along the profile. In the present work, the precipitation of carbonates seems the most important process, especially for elements such as Zn and Mn. Secondary precipitation of sulphides enables the trapping of metals at sulphur-rich levels.

Fly ash is one of the residues produced during combustion of coal, and its disposal is a major environmental concern throughout coal-based power-generated counties. Deficiencies of essential nutrients, low soil microbial activity, and high-soluble salt concentrations of trace elements are some of the concerns for reclamation of fly ash ponds. The effect of fly-ash-adapted arbuscular mycorrhizal (AM) fungi and phosphate solubilizing fungus Aspergillus tubingensis was studied on the growth, nutrient, and metal uptake of bamboo (Dendrocalamus strictus) plants grown in fly ash. Co-inoculation of these fungi significantly increased the P (150%), K (67%), Ca (106%), and Mg (180%) in shoot tissues compared control plants. The Al and Fe content were significantly reduced (50% and 60%, respectively) due to the presence of AM fungi and A. tubingensis. The physicochemical and biochemical properties of fly ash were improved compared to those of individual inoculation and control. The results showed that combination of AM fungi and A. tubingensis elicited a synergetic effect by increasing plant growth and uptake of nutrients with reducing metal translocation.

We report the isolation of a new bacterium species (named as DN-06) that degrades pyridine, a model compound containing both carbon and nitrogen, from the aerobic activated sludge in a coking wastewater treatment plant. DN-06 was identified as Achromobacter sp. using 16S rDNA sequence analysis. In batch culture, more than 95% of pyridine (500 mg/L) was degraded within 18 h by DN-06 grown at 35°C and pH 8 with agitation at 170 rpm. Degradation experiments of pyridine at different initial concentrations (50–4,300 mg/L) revealed that pyridine was an inhibitory substrate, and that neither yield coefficient Y nor endogenous decay coefficient K d was a constant. The values of Y and K d were 0.55–0.74 and 0.0032–0.0057 h−1, respectively. Five kinetic models (Haldane, Yano, Aiba, Webb, and Monod) were fitted to the experimental growth kinetic data. Models of Haldane and Yano (correlation coefficient R 2 = 0.929) were the most suitable models. For Haldane kinetic model, the values of μ max, K s, and K i were 0.161 h−1, 142.6 mg/L, and 4234.8 mg/L, respectively. The large values of Y and K i indicated that DN-06 had good tolerance against high pyridine concentrations. These results indicated possible future applications of Achromobacter sp. DN-06 in removing pyridine from industrial wastewaters, as well as in destroying pyridine in concentrated solutions during further treatment of trial water coupling with adsorption technology.

To date, numerous studies have employed single type nitrogen (N) addition methods in reporting influences of N deposition on soil extracellular enzymatic activities (EEA) during litter decomposition in forest ecosystems. As natural atmospheric N deposition is a set of complex compounds including inorganic N and organic N, it is essential for investigating responses of soil EEA to various mixed N fertilization. In a subtropical forest stand in Zijin Mountain, East China, various N fertilizers with different inorganic N and organic N ratios were added to soils monthly from 2008 to 2009. Samples were harvested from N fertilized and control plots every 4 months. Subsequently, six EEA were assayed. A laboratory experiment was also conducted simultaneously. Both field and laboratory experiments showed that various mixed N fertilizations revealed different influences on soil EEA. Acceleration of most soil EEA by mixed N fertilization was greater than that of single N fertilization. The majority of soil extracellular enzymes exhibited the highest activities under mixed N fertilization, with the ratio of inorganic N to organic N at 3:7. These results suggested that N type and ratio of inorganic N and organic N were important factors controlling soil EEA, and the 3:7 ratio of inorganic N and organic N may be the optimum for soil EEA.