Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)-containing wastewater using granular activated carbon (GAC)–biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC–biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k 2) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC–biofilm SBR system.

We assessed the suitability of two nonnative poeciliid fishes—western mosquitofish (Gambusia affinis) and sailfin mollies (Poecilia latipinna)—for monitoring selenium exposure in desert pupfish (Cyprinodon macularius). Our investigation was prompted by a need to avoid lethal take of an endangered species (pupfish) when sampling fish for chemical analysis. Total selenium (SeTot) concentrations in both poeciliids were highly correlated with SeTot concentrations in pupfish. However, mean SeTot concentrations varied among fish species, with higher concentrations measured in mosquitofish than in mollies and pupfish from one of three sampled agricultural drains. Moreover, regression equations describing the relationship of selenomethionine to SeTot differed between mosquitofish and pupfish, but not between mollies and pupfish. Because selenium accumulates in animals primarily through dietary exposure, we examined fish trophic relationships by measuring stable isotopes (δ 13C and δ 15N) and gut contents. According to δ 13C measurements, the trophic pathway leading to mosquitofish was more carbon-depleted than trophic pathways leading to mollies and pupfish, suggesting that energy flow to mosquitofish originated from allochthonous sources (terrestrial vegetation, emergent macrophytes, or both), whereas energy flow to mollies and pupfish originated from autochthonous sources (filamentous algae, submerged macrophytes, or both). The δ 15N measurements indicated that mosquitofish and mollies occupied similar trophic levels, whereas pupfish occupied a slightly higher trophic level. Analysis of gut contents showed that mosquitofish consumed mostly winged insects (an indication of terrestrial taxa), whereas mollies and pupfish consumed mostly organic detritus. Judging from our results, only mollies (not mosquitofish) are suitable for monitoring selenium exposure in pupfish.

Phenol is a typical contaminant of the environment generated by many industries. Several fungi had been reported to degrade phenol as the only source of carbon and energy, but many of them are not useful to apply in soil bioremediation process. In this work, we study the dynamics of phenol degradation by a Penicillium chrysogenum, isolated from soil. Degradation of phenol was studied at room temperature and resting mycelium conditions. High specific degradation rates were obtained. Inhibition was observed on the specific growth rate (30 mg l1) and the degradation rate (200 mg l−1). Experimental results were fitted to several models during exponential phase, with the Andrews-Haldane model given the best fit. Dynamic mass balance equations for biomass and phenol during the exponential and stationary growth phases were solved and compared very satisfactorily to experimental outcomes. P. chrysogenum degrades phenol completely during the exponential and stationary growth phases. The results obtained are relevant for its practical applications in soil decontamination processes. Model predictions were satisfactory. This is the first work which describes a kinetic model for phenol biodegradation using a filamentous fungus considering both, exponential and stationary phases, and the first one in which a Penicillium isolate is used.

This work was undertaken to study the influence of soil type and its physical and chemical properties on uranium sorption and bioavailability, in order to reduce the uncertainty associated with this parameter in risk assessment models and safe food production. The tests were conducted on three types of Serbian soils: alluvium, chernozem, and gajnjaca, from which 67 samples were taken. Dominant factors of uranium mobilisation: the specific content of total/available form of uranium and phosphorus, the degree of acidity (pHKCl), and humus content and their correlation, were analysed. Content of available uranium form, according to the type of soil decreases in the following order: gajnjaca > alluvium > chernozem. It was found the medium correlation between pH values and available content of uranium in chernozem and gajnjaca, statistically significant at the level of significance of 99% and the alluvium at the level of significance of 95%. Correlation coefficients in all cases were negative, indicating that the reduction in pH increases the mobility of uranium and thus its availability for the adoption of the plants. Soil pH was the only dominant factor that significantly controlled the uranium value with no further significant contribution of other soil parameters.

Three different solventless sample preparation techniques based on microextraction, membrane extraction, and headspace extraction have been developed and optimized for determination of trihalomethanes in drinking water by gas chromatography electron capture detector and mass spectrometry detection. The techniques employed were headspace (HS) solid-phase microextraction, hollow fiber liquid-phase microextraction (HFLPME) and HS extraction. All techniques used were optimized with different experimental designs in order to select the most relevant variables which significantly affect the different processes. The different analytical figures of merit such as limit of detection (LOD), limit of quantification, reproducibility, accuracy, and linear dynamic range were obtained. The new HFLPME method applied used a hollow fiber membrane of polypropylene and the optimized variables were extraction time, extraction temperature, and salting-out effect. The software MODDE 6.0 was used and its design was one central composite on face with a total of 17 runs. The best conditions for the HFLPME were 20 min, 40°C, and 10% NaCl, respectively. The LODs ranged from 0.018 μg·L−1 (for CHClBr2) to 0.049 μg·L−1 (for CHBr3), being this technique the most sensitive one among those studied. Finally, after having optimized the sample preparation techniques and chromatographic conditions, several water samples were taken in two different water treatment plants in Spain (Zaragoza) and Colombia (Viterbo, Caldas). The results obtained are shown and discussed.

To evaluate plant responses and compare metal uptake by different plants, several parameters and references have been used by researchers in the last few years. However, they express only the first-level comparison, i.e. biogeochemical comparison of different media (plant and soil) occurs in one place, at the same time and under the same circumstances. To integrate information about metal concentration in different media or plant organ and provide comparison of the process between control and treated cases, the second-level factors, the dynamic factors, are needed. Differently from the factors mentioned in the existing literature, they are able to show changes in processes under environmental changes rather than changes only in metal quantities. They are related both to internal (physiological) and external (ecological) factors. The paper introduces the use of dynamic factors for assessment of transfer and translocation of metals (Zn, Pb, Ni, Mn, Cu and Cr) in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula) and black alder (Alnus glutinosa). Factor values and their implications are discussed in the paper.

In epidemiological studies, ultrafine particle (UFP) data from a single monitoring site are generally used as a measure of population exposure potentially resulting in exposure misclassification. From August 2009 to October 2010, 1-week campaigns were conducted during each season. The temporal and spatial variations of UFP number size distributions were investigated at 12 monitoring sites distributed across a 9 × 9 km urban area in Rochester, New York using a Fast Mobility Particle SizerTM spectrometer. The overall average number concentrations of 5.6- to 560-nm particles in summer, winter, spring, and fall were 9,025, 10,939, 4,955, and 14,485 cm−3, respectively. Coefficients of divergence and correlation coefficients were calculated between site pairs to assess the spatial heterogeneity in the particle number size distributions. Moderate spatial divergence and uniform temporal variation were found for the chosen sites. Elevated UFP number concentrations were observed near highways, off-road diesel engines, and residential wood combustion sources, indicating significant contributions to the UFP exposure of people living adjacent to these sources. Our results suggest that one stationary monitoring site may not represent the actual human UFP exposure over a whole urban area.

Poultry litter leachate (PLL) is known to contain a variety of contaminants including endocrine disrupting compounds (EDCs). This study analyzed the presence of steroids and contaminants in samples of poultry litter from a broiler poultry operation in Maryland, USA. Litter samples were homogenized, hydrated, incubated for two time periods (4 and 24 h) at two temperatures (20°C and 37°C), filtered, and analyzed for steroids and anthropogenic contaminants. In addition, duplicate samples were spiked with 17‐β estradiol (E2) and testosterone (T), and β-glucuronidase and aryl sulfatase, to measure steroid recovery and the presence of conjugates, respectively. A steroid recovery rate of 71 and 73% was obtained from E2 and T spiked samples, respectively. Increased incubation duration demonstrated an increased trend in E2 and a decreased trend in androgen (T and/or dihydrotestosterone [DHT]) concentrations, regardless of temperature. In contrast, increased incubation temperature displayed different trends in E2 and androgen concentrations. High temperature with a 4-h incubation resulted in an increased trend in androgen with no effect on E2. However, after 24 h of incubation at high temperature, an increased trend in E2 was observed with no effect on androgen. The presence of de-conjugating enzymes resulted in a greatly increased trend in T concentrations with a slight increased trend of E2 concentrations. Trace amounts of several metals and anthropogenic compounds were detected. Arsenic, barium, endosulfan, and bis (2-ethylhexyl) phthalate were detected at quantifiable levels. This study demonstrates that PLL contains potential EDCs and contaminants that can be toxic to, and bioaccumulate in, aquatic fauna. Determination of EDC concentrations in environmental samples is important to elucidate potential detrimental effects of agricultural runoff on aquatic wildlife.

Faecal contamination of drinking water extracted from alluvial aquifers can lead to severe problems. River water infiltration can be a hazard for extraction wells located nearby, especially during high discharge events. The high dimensionality of river–groundwater interaction and the many factors affecting bacterial survival and transport in groundwater make a simple assessment of actual water quality difficult. The identification of proxy indicators for river water infiltration and bacterial contamination is an important step in managing groundwater resources and hazard assessment. The time resolution of microbial monitoring studies is often too low to establish this relationship. A proxy-based approach in such highly dynamic systems requires in-depth knowledge of the relationship between the variable of interest, e.g. river water infiltration, and its proxy indicator. In this study, continuously recorded physico-chemical parameters (temperature, electrical conductivity, turbidity, spectral absorption coefficient, particle density) were compared to the counts for faecal indicator bacteria, Escherichia coli and Enterococcus sp. obtained from intermittent sampling. Sampling for faecal indicator bacteria was conducted on two temporal scales: (a) routine bi-weekly monitoring over a month and (b) intense (bi-hourly) event-based sampling over 3 days triggered by a high discharge event. Both sampling set-ups showed that the highest bacterial concentrations occurred in the river. E. coli and Enterococcus sp. concentrations decreased with time and length of flow path in the aquifer. The event-based sampling was able to demonstrate differences in bacterial removal between clusters of observation wells linked to aquifer composition. Although no individual proxy indicator for bacterial contamination could be established, it was shown that a combined approach based on time-series of physico-chemical parameters could be used to assess river water infiltration as a hazard for drinking water quality management.

Four devices developed for measuring settling velocity distributions of combined sewer overflow (CSO) solids were applied to dry and wet weather flow samples from an urban area serviced by combined sewers (Welland, ON, Canada). The settling column-based methods (the Aston, Brombach and US Environmental Protection Agency columns) produced comparable results indicating minimal differences in settleability of dry and wet weather samples. The elutriation apparatus, which assessed settling velocities in a flowing medium, indicated higher settleabilities than the column methods. This was attributed to enhanced opportunities for particle coalescence in the flowing medium, which should better approximate actual sedimentation conditions. While the elutriation apparatus also indicated larger differences in settleabilities between dry and wet weather samples than the column methods, this difference was not statistically significant. Experimental distributions of particle settling velocities were approximated by a mathematical function, which was then used to estimate partial settling of total suspended solids (TSS) with settling velocities smaller than the clarifier overflow rate. The TSS removal target of 50%, which is applicable to CSOs in Ontario, could be met for overflow rates ranging from 4.7 to 6.8 m/h, for dry and wet weather flows, respectively, based on the average settling velocities measured. Experimental data collected in the study indicate that the design of CSO storage and settling facilities is affected, among other factors, by both the apparatus used to assess CSO settleability and the inter-event variability of CSO settling characteristics.