Bacteria, fungi and viruses are often encountered in aerosols and they can be pathogenic or cause allergies following inhalation. Wastewater treatment facilities have been found to generate bioaerosols, which are transported by the prevailing winds downstream to areas that can be up to several hundred meters away. Bioaerosol formation has a significant effect on air quality in the vicinity of the treatment plants. The amount and characteristics of the formed bioaerosols depend on the aeration system employed at the aeration tank of the wastewater treatment facility. In this work we determined Enterobacteria in air and wastewater samples at the main wastewater treatment facility of the city of Chania (Crete, Greece). Concentrations of airborne bacteria were measured near the aeration and sedimentation tanks. Samples of airborne bacteria were taken by using Merck's MAS-100 bioaerosol collector followed by incubation and enumeration of the colonies. The use of different growth media enabled the separation and enumeration of several classes of microorganisms. As part of this study, Enterobacteria in air samples were also determined by filtration sampling followed by analysis of the collected microorganisms using DAPI staining to determine total cell counts (both viable and non-viable cells). Fluorescence in situ hybridization (FISH) with specific 23S rRNA probes was also used in order to identify specific groups of microorganisms (well known pathogens) present in the bioaerosols. The analysis was also performed in wastewater taken from the aeration and secondary sedimentation tanks in an effort to correlate the airborne bacteria with those in the wastewater.

A new approach to vapor phase elemental mercury capture has been explored; this approach exploits an ionic liquid coating layer to oxidize elemental mercury for subsequent immobilization by chelating ligands. The room temperature ionic liquid 1-butyl-1-methyl pyrrolidinium bis(trifluoromethane sulfonyl)imide (P₁₄) was selected for study based on its oxidation potential window, thermal stability, and low vapor pressure. Tests were also completed in which KMnO₄ was added to P₁₄ to form a new ionic liquid, P₁₄-KMnO₄, with a higher oxidation potential. In room-temperature bulk liquid phase capture experiments, 59% of the elemental mercury in the inlet gas was captured using P₁₄ alone; mercury capture using P₁₄-KMnO₄ was quantitative. P₁₄ and P₁₄-KMnO₄ coatings were successfully applied to mesoporous silica substrates and to silica substrates functionalized with mercury chelating ligands. The coating layers were found to be thermally stable up to 300°C. Fixed-bed tests of nonfunctionalized silica coated with P₁₄ showed an elemental mercury uptake of 2.7 mg/g adsorbent at 160°C; at the same temperature, functionalized silica coated with P₁₄-KMnO₄ showed an elemental mercury capacity of at least 7.2 mg/g adsorbent, several times higher than that of activated carbon. The empty bed gas residence time in these tests was 0.04 s. A chelating adsorbent incorporating P₁₄ in the coating layer, may be capable of simultaneous removal of elemental and oxidized mercury from coal combustion flue gases.

This study was conducted to investigate the relationship between ground-dwelling spider communities and the degree of soil contamination of heavy metals, Cd and Pb. Six sites were selected according to expected differences in Cd and Pb contamination levels in soil and similarity in vegetation composition. Ground-dwelling spiders were collected monthly in 2003 and 2004 by pitfall trapping. Species diversity of ground-dwelling spiders between unpolluted and moderately polluted sites was not significantly different although the value was higher in the unpolluted site. Species diversity tended to decrease with increasing Pb levels in soil although no statistical significance was obtained. No trend was shown between species diversity and Cd levels in soil. The community structure of ground-dwelling spiders was similar for the two types of sites. Overall ground-dwelling spider communities may be not sensitive enough to discriminate moderate heavy metal contamination levels in soil. However, among the dominant spider families, the composition and structure of Linyphiidae separated unpolluted and moderately polluted sites. Pardosa astrigera and P. laura (Lycosidae) have a potential as heavy metal accumulator indicator species and Oedothorax insulanus (Linyphiidae) has a potential as a heavy metal sentinel indicator species.

This paper presents an improved version of a general, process-based mass-balance model (LakeMab/LEEDS) for phosphorus in entire lakes (the ecosystem scale). The focus in this work is set on the boundary conditions, i.e., the domain of the model, and critical tests to reveal those boundary conditions using data from a wide limnological range. The basic structure of the model, and many key equations have been presented and motivated before, but this work presents several new developments. The LakeMab-model is based on ordinary differential equations regulating inflow, outflow and internal fluxes and the temporal resolution is one month to reflect seasonal variations. The model consists of four compartments: surface water, deep water, sediment on accumulation areas and sediment on areas of erosion and transportation. The separation between the surface-water layer and the deep-water layer is not done from water temperature data, but from sedimentological criteria (from the theoretical wave base, which regulates where wind/wave-induced resuspension of fine sediments occurs). There are algorithms for processes regulating internal fluxes and internal loading, e.g., sedimentation, resuspension, diffusion, mixing and burial. Critical model tests were made using data from 41 lakes of very different character and the results show that the model could predict mean monthly TP-concentrations in water very well (generally within the uncertainty bands given by the empirical data). The model is even easier to apply than the well-known OECD and Vollenweider models due to more easily accessed driving variables.

The European Union has introduced a new bathing water directive where future classification of recreational waters will be based on the microbial parameters Escherichia coli, and intestinal enterococci. Introduction of enterococci as a new quality parameter may pose a challenge in some areas because relatively less is known about these organisms compared to E. coli. In the present study, the relative abundance of intestinal enterococci, E. coli, and ten fecal sterol and stanol biomarkers were investigated in water and sediment at two estuarine beach sites affected by fecal pollution. In the bathing water, enterococci were relatively more abundant at low E. coli concentrations. In the sediment, enterococci were generally more abundant than E. coli with surface concentrations between 1.0 × 10² and 4.5 × 10³ CFU cm⁻³. Enterococci populations were relatively similar in water and sediment, and were phenotypically different from that of nearby pollution sources. The putative human specific genetic marker esp in Enterococcus faecium was not detected in water or sediment samples despite occasional inputs of human waste from storm water overflows. Sterol and stanol profiles suggested a direct link between water and sediment pollution profiles on days with wind conditions that facilitated resuspension. Sediment resuspension may occur at wind speeds exceeding 6–8 m s⁻¹, and could contribute significantly to enterococci concentrations in the overlying water. The study emphasized that recontamination of the water column due to wind induced resuspension should be considered when evaluating indicator levels and microbial hazards in estuarine recreational waters.

The paper describes a novel approach to reduce ammonia emissions from Concentrated Animal and Feeding Operations (CAFO) in general, and from poultry houses in particular. The approach is based on installing a dedicated air capturing system on the feeding infrastructure that draws air from close to the litter. Air at these locations has NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. Moreover, while the dedicated waste air drawing system can work continuously, the operation of the ventilation system is intermittent and directed towards maintaining the birds climatically-comfort. The NH₃₍g₎ rich waste air is conveyed to an acidic (0 < pH < ~5) bubble column reactor in which ammonia is converted to [Formula: see text]. The reactor operates in a batch mode, starting at pH 0 (1 N HCl solution) and is switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurs, at around pH 5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency is practically 100% throughout the process as long as the face velocity is below 4 cm/s. The advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product (a high concentration ammonia solution) and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. A larger scale pilot study is required for fine-tuned cost estimation.

This study presents the analysis of two series of concentrations of airborne particulate matter (APM) collected in two exploratory campaigns aimed at elucidating the source-receptor problem (SRP) in the metropolitan area of Buenos Aires. Although several techniques have been previously applied to interpret these measurements, we have almost exclusively used here the method of angular distances among objects (ADO) to discuss its advantages as a tool in understanding environmental questions within the source-receptor framework. We present a simple method of calculating the ADO, explain its chemical interpretation and the information that is possible to get by classifying the angular distances. A comparison among ADO with principal component analysis and Kohonen artificial neural networks is also discussed.

Littoral zones are characterized by gradients in depth and vegetation biomass, influencing nutrient retention capacity. A field experiment was conducted in a Phragmites australis dominated littoral zone to investigate nutrient retention and its effect on surface water quality. Measurements were done in mesocosms where water levels could be manipulated. Nutrient status was investigated along a gradient perpendicular to the shore during two growing seasons, one with a stable water level and one with a gradually decreasing water level. Nutrient concentrations in sediment, soil pore water and surface water were significantly lower in the vegetated than in the unvegetated zone. The negative correlations of nutrients in sediment and water, with nutrient contents of the vegetation suggest a direct effect of the vegetation. Nutrient uptake and biomass of the vegetation was higher in continuously flooded soils than in seasonally emerging sediments higher along the littoral gradient, probably due to the increased salinity in drained zones. Denitrification rate was highest in the unvegetated zone and was positively related to water level. Flooded littoral zones did result in a higher nutrient retention than drained zones. On small scale, for an optimal nutrient retention a fluctuating regime is not necessarily better suited than a stable water level, but on a larger scale it can substantially increase the width of the vegetated zone. It is important to optimize conditions for helophyte growth since the positive effect of vegetation on nutrient retention, at least at local scale, has been demonstrated in this study.

The aim of this in situ study was to investigate the fatty acid (FA) composition and content in roots and shoots of Lolium perenne and Trifolium repens, grown under heavy metal stress (Cd, Pb, Zn). The composition of FA was quite similar for the two plants and the two organs; main FA were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). For both plants, the major FA that characterized the roots was C18:2 whereas C18:3 was the prominent FA in shoots. For the first sampling (S1), in the roots of L. perenne and T. repens, polyunsaturated fatty acids (PUFA) were affected by metal contamination while, in the second sampling (S2), PUFA were affected in the shoots of the two plants. This alteration of PUFA was well correlated with the bioaccumulation factor of metals which decreased in roots and increased in shoots with the time. Moreover, a positive correlation was found between the PUFA decrease and the malondialdehyde (MDA) content, indicating the occurrence of a lipid peroxidation induced by the metal stress.

Water resources are threatened globally and declining water quality is primarily due to stormwater, agricultural, urban, and mining runoffs. Steamboat Creek in Nevada is the largest non point source (NPS) of pollution to the Truckee River. Treatment wetlands are a cost-effective and reliable technique to control NPS pollution, therefore, a large-scale wetland along Steamboat Creek has been proposed as a component of a regional watershed restoration plan. This study used ten parallel pilot-scale wetland mesocosms, and tested the effects of drying and rewetting, hydraulic retention time (HRT), and high nitrogen loading on the efficiency of nutrient and total suspended solids (TSS) removal. Drying and rewetting produced noticeable effects on nutrient retention, but the effect was short-lived. During longer HRT period nutrient removal in manipulated mesocosms with an 8 h HRT were higher than controls with a 4 h HRT. Reducing the HRT from 4 h to 30 min further decreased nutrient interception. During increased influent nitrogen loading (9.5 ± 2.4 mg l⁻¹), manipulated mesocosms functioned as sinks for total nitrogen (TN) with removal efficiency increasing from 45 ± 13% to 87 ± 9%. The average change in TN concentration was 9.1 ± 2.2 mg l⁻¹. Drying/rewetting and varying HRT influenced total phosphorus (TP) and TSS similarly, and TP removal was associated with TSS removal. Results can help make decisions regarding wetland construction, management, and operation more effective in order to reduce nutrient loads to the Truckee River.