The effect of humic acid (HA), on the adsorption and transport of arsenic (As) onto and within a model iron oxide-based adsorbent, iron oxide-coated diatomite (IOCD), is investigated. Experimental results indicate that the adsorption of both As and HA is highly pH-dependent. As uptake was suppressed by HA, with the level of suppression increasing with HA concentration. The suppression is attributed to the partial coverage of the adsorption sites, as confirmed by elemental analysis. Adsorption energy analysis indicates that for As(III), the main interaction with IOCD is physical adsorption, whereas for As(V), it is more likely ion exchange. The presence of HA may alter the adsorption energy and interaction of As with the adsorbent, particularly at higher HA concentrations. Kinetic results indicate that HA did not affect the diffusional transport of As in systems with both As and HA. However, for IOCD preloaded with HA, the adsorption kinetics of As was significantly slower, although the As uptake was similar to the conditions of co-sorption with HA. The slower kinetics and similar equilibrium uptake of As in the HA-preloaded IOCD system may be attributed to the partial blockage of the intraparticular pores within IOCD, which slowed down the diffusion of As.

Early-life exposure to pollutants, such as lead, may have long-lasting consequences on health, behavior, and cognition. However, experiments on delayed effects of specific pollutants are very rare in wild animals. We experimentally exposed wild nestling great tits (Parus major) to dietary lead (high, low, or control group) in levels relevant to exposure levels of wild populations in Europe and studied delayed effects on phenotypic and behavioral traits in captivity. We also included a group of birds from a vicinity of a copper smelter, exposed to a mixture of toxic metals and altered food supply during development. This experimental setup allowed us to compare the strength of direct (exposure to lead per se) and indirect (pollution-related changes in diet) effects of pollutants. Our experimental lead treatment significantly increased lead levels in bone and feces compared with controls. However, we found no carry-over effect of early-life dietary lead on morphology, plumage coloration, or heat shock proteins. Treatment did not affect activity, exploration, neophobia, or success in learning and spatial memory task. We conclude that with the exposure levels and relatively short exposure period used, delayed effects on the measured traits were not found. However, it is important to further study other types of behavioral traits and ultimately fitness effects.

This study assessed the suitability of passive sampler extracts for use with a GC-MS-database rapid screening technique for around 940 organic chemicals. Chemcatcher™ passive sampler systems containing either Empore™ SDB-XC or C18FF disks were deployed at 21 riverine sites in and near Melbourne, Victoria, Australia, for a period of 28 days during September–October 2008. Methanolic elution of the SDB-XC and C18FF disks produced an extract that, after evaporation and inversion into hexane, was compatible with the GC-MS-database method enabling over 30 chemicals to be observed. The sources of the non-agricultural chemicals are still unclear, but this study was conducted in a relatively dry season where total rainfall was approximately 40 % lower than the long-term mean for the catchment during the study period. Thus, the risks may be greater in wetter seasons, as greater quantities of chemicals are likely to reach waterways as the frequency, extent and intensity of surface run-off events increase. This study provides valuable information for policy and decision-makers, both in Australia and other regions of the world, in that passive sampling can be conveniently used prior to analysis by multi-residue techniques to produce data to assess the likely risks trace organic chemicals pose to aquatic ecosystems.

A coupling technique is developed to predict the behavior of a buoyant river plume in a lake. The model incorporates a 3D hydrodynamic model (POMGL) and a 3D particle tracking model (Partic3D) for the far-field transport computations. The source conditions for the particle tracking model are obtained from a near-field model derived from the characteristics of the plume analyzed from extensive field studies on the Grand River plume, Lake Michigan. The empirical near-field model was developed to predict the geometry of the plume, dilution, and centerline trajectory near the river mouth, and to provide the concentration and location of the particles to be released in the far field. The coupled empirical-numerical model shows improved predictions in the near field versus the single numerical model. The present results strongly advocate the use of model combinations in order to improve coastal diffusion and transport processes. The primary application of the technique is in recreational water early-warning and forecasting systems that will estimate the immediate and short-term risk of exceeding pathogen indicator concentration criteria in lakes and coastal areas.

Biofiltration of an air stream polluted with diffuse CH₄ concentrations of 0.19 % (v v⁻¹) was carried out. These emissions can be encountered at different industrial facilities such as wastewater treatment plants and landfills. The effect of ammonium supplied in the nutrient solution was studied in a range from 0 to 1 g N-NH₄ ⁺ L⁻¹, taking account its effect on CH₄ removal efficiency (RE), CO₂ production, ammonium conversion and the occurrence of exopolymeric substances. Additional batch assays were performed in order to evaluate the most suitable pH and temperature ranges for the biomass used as inoculum. A conventional biofilter was operated along 225 days achieving maximum CH₄ elimination capacities of up to 11.2 g CH₄ m⁻³ h⁻¹, corresponding to REs of 62 %, using 0.52 g N L⁻¹ of ammonia as nitrogen source in the nutrient solution and operating at an empty bed residence time of 4.4 min. CO₂ production values confirmed that most of this elimination was biological and not absorption into the liquid phase. The occurrence of instability periods resulted in a clear increase of the soluble microbial products (SMPs) contained in the liquid phase, especially in the protein fraction, which could be used as a monitoring tool to follow the stress conditions of the biofilter. Results indicate interesting links between the performance of the biofilter and the presence of extracellular polysaccharide and protein concentration in the liquid phase, with increasing concentrations detected when the process was not stable.

One of the most important particles of biological origin present in the air is pollen grains of plants. Having basic biological function in the process of pollination, pollen grains of some plant species can cause allergic reactions among 20–30 % of the human population and thus affect their health and overall quality of life. Bearing in mind the potential influence air pollutants and meteorological parameters may have on release of pollen and granules of allergen from pollen, concentrations of air pollutants and 26 different anemophilous aeropollen types as well as meteorological parameters were established in a 5-year period (2009–2013) in Subotica, Northern Serbia. Spearman’s rank correlation was made for statistical analysis of relationships between concentration of some air pollutants (sulphur dioxide, nitrogen dioxide, soot, particulate matter (PM)₁₀ and PM₂.₅), meteorological factors (temperature of air, humidity, wind speed, cloud index) and airborne pollen. In most of the examined years, significant positive correlations were determined between temperature and total pollen concentration, while significant negative correlations were established between humidity as well as cloud index and total pollen concentration, clearly proving the influence these meteorological parameters have on pollination of all examined species.

The removal efficiencies of four different parabens (methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP)) using Fenton reagent, UV irradiation, UV/H₂O₂, and UV/H₂O₂/Fe²⁺ were evaluated to assess the level of paraben degradation achieved using different advanced oxidation processes (AOPs). UV irradiation by itself provided paraben conversions between 27 and 38 % after a reaction time of 180 min. The UV/H₂O₂ system increased the paraben conversion to values between 62 and 92 %, and the Fenton process was revealed as inefficient in paraben degradation within the experimental conditions used. Photo-Fenton presented similar removal rates to the UV/H₂O₂ process. Among the four parabens studied, butylparaben was the most easily removed, and it was possible to attain degradations higher than 90 %. In the UV/H₂O₂ and photo-Fenton processes, the overall kinetic constant could be split into two main components: direct oxidation by UV radiation (photolysis) and oxidation by free radicals (mainly HO•) generated from the photodecomposition of H₂O₂. This work reveals that UV-driven oxidation processes can be widely used to remove parabens from contaminated aqueous solutions.

The performance of a laboratory-scale biofilter packed with a mixture of compost and woodchip on formaldehyde removal from polluted air streams was investigated. The reactor was inoculated with aerobic sludge as a source of bacteria, obtained from a municipal wastewater treatment plant. A nutrient solution was daily added to the reactor media. An airflow containing different concentrations of formaldehyde (from 20 ± 2 to 276 ± 5 mg m⁻³) was introduced into the reactor. In inlet formaldehyde concentration, an average removal efficiency and elimination capacity of 91 % and 0.36 g m⁻³ h⁻¹were attained, respectively, at180 s empty bed residence time (EBRT). After acclimatization of the system for increased formaldehyde concentrations of up to 276 ± 5 mg m⁻³and for EBRT of 180 s, those values were stabilized at around 72 % and 3.98g⁻³ h⁻¹, respectively. The experimental results showed that the system was effective for a high loading rate of formaldehyde with an acceptable EBRT. Compared to the application of compost alone as a media, a mixture of compost and woodchip (50/50 v/v%) enhanced the performance of the biofilter. The most predominant microorganism involved in the biodegradation of formaldehyde was a species of citrobacter called Citrobacter freundii, an aerobic gram-negative bacillus. Pressure drop of the reactor over the entire operations was about 1 mmH₂O m⁻¹.

The estimated diffusion fluxes of methane (CH₄) and carbon dioxide (CO₂) at the sediment–water interface in the Rzeszów Reservoir in southeastern Poland are presented. The relevant studies were conducted during 2009, 2010, and 2011. Calculated fluxes ranged from 0.01 to 2.19 mmol m⁻² day⁻¹and from 0.36 to 45.33 mmol m⁻² day⁻¹for methane and carbon dioxide, respectively. While the values for calculated diffusion fluxes of methane are comparable with those reported for other eutrophic reservoirs, much higher values were obtained here for carbon dioxide. The resulting values of δ¹³C-CH₄and the fractionation coefficients between methane and carbon dioxide (αCH₄-CO₂) suggest that methane in the sediment of the Rzeszów Reservoir is produced by acetate fermentation, while the hydrogenotrophic methanogenic process is of successively greater importance with increasing depth. In the top layer of the sediment, 24–72 % of CO₂came from methanogenesis, while the contribution made by the degradation of organic matter by methanogenesis to CO₂was greater in the deeper layer.

The behaviour of sulphate-reducing microbial community was investigated at the oxic–anoxic interface (0–2 cm) of marine sediments when submitted to oil and enhanced bioturbation activities by the addition of Hediste diversicolor. Although total hydrocarbon removal was not improved by the addition of H. diversicolor, terminal restriction fragment length polymorphism (T-RFLP) analyses based on dsrAB (dissimilatory sulphite reductase) genes and transcripts showed different patterns according to the presence of H. diversicolor which favoured the abundance of dsrB genes during the early stages of incubation. Complementary DNA (cDNA) dsrAB libraries revealed that in presence of H. diversicolor, most dsrAB sequences belonged to hydrocarbonoclastic Desulfobacteraceae, suggesting that sulphate-reducing microorganisms (SRMs) may play an active role in hydrocarbon biodegradation in sediments where the reworking activity is enhanced. Furthermore, the presence of dsrAB sequences related to sequences found associated to environments with high dinitrogen fixation activity suggested potential N₂ fixation by SRMs in bioturbated-polluted sediments.