This study applied the Model of Acidification of Groundwater in Catchments (MAGIC) to estimate the sensitivity of 66 watersheds in the Southern Blue Ridge Province of the Southern Appalachian Mountains, United States, to changes in atmospheric sulfur (S) deposition. MAGIC predicted that stream acid neutralizing capacity (ANC) values were above 20 μeq/L in all modeled watersheds in 1860. Hindcast simulations suggested that the median historical acidification of the modeled streams was a loss of about 25 μeq/L of ANC between 1860 and 2005. Although the model projected substantial changes in soil and stream chemistry since pre-industrial times, simulated future changes in response to emission controls were small. Results suggested that modeled watersheds would not change to a large degree with respect to stream ANC or soil % base saturation over the next century in response to a rather large decrease in atmospheric S deposition. Nevertheless, the magnitude of the relatively small simulated future changes in stream and soil chemistry depended on the extent to which S emissions are reduced. This projection of minimal recovery in response to large future S emissions reductions is important for designing appropriate management strategies for acid-impacted water and soil resources. Exploratory analyses were conducted to put some of the major modeling uncertainties into perspective.

The presence of endocrine-disrupting chemicals (EDCs) in wastewater effluent is a major concern to the scientific community. This research effort was aimed at investigating Fenton-like degradation of two EDCs 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). The results of the study showed that E2 and EE2 were effectively removed by the Fenton-like oxidation process. Removal efficiencies of 95% and 98% at ferric concentration of 1 × 10−3 M (58.6 mg l−1) were achieved for E2 and EE2, respectively. The kinetics of Fenton-like degradation of E2 and EE2 were adequately described by the pseudo second order kinetic model. Values of 27.8 and 22.5 kJ mol−1 were obtained for the activation energy for E2 and EE2, respectively, from the Arrhenius-type plot, showing that the process does not just involve radical reactions but also intermediate reaction steps involving radical–molecule or ion–molecule reactions. The presence of high dissolved organics in wastewater significantly reduced the removal efficiencies. The reaction by-products for E2 and EE2 were more stable to the oxidation process and more readily biodegradable. Fenton-like oxidations therefore offers a promising alternative for the removal of these EDCs in wastewater treatment applications at the tertiary treatment stage.

Batch adsorption experiments were carried out to evaluate the effect of type of crop residues and chemical pretreatment solutions on the removal efficiency of heavy metal ions at different concentrations of synthetic wastewater solutions. Rice straw, cotton stalks, and maize stalks were pretreated with different solutions (i.e., sulfuric acid, oxalic acid, sodium hydroxide, and distilled water as the control treatment) in order to increase their metal-binding capacity. Results indicated that cotton stalks were the best biosorbent material according to their efficiency in removal of heavy metal ions. Sodium hydroxide was the best chemical pretreatment method for stimulating the biosorption capacity of crop residues. Ions of Pb2+ had the highest biosorption ratio among all competitive ions, whereas Mn2+ ions had the lowest. The removal efficiency decreased as the concentration of heavy metal ions increased in aqueous solutions. Sorption equilibrium isotherms could be described by the Langmuir model in most cases, whereas an isotherm of S shape was observed in other cases, which did not follow the Langmuir isotherm model. In conclusion, cotton stalks pretreated with sodium hydroxide could be used as an efficient technique for wastewater remediation prior to irrigation due to its low-cost, little processing, and high biosorption capacity.

The levels of 131I and six natural radionuclides (238U, 226Ra, 210Pb, 228Ra, 224Ra, and 40K) were determined in sewage sludge samples obtained from an urban wastewater treatment plant that services a medium-sized town in Spain. Secondary treatment of wastewater consisting of anaerobic, anoxic, and oxic stages is collectively called A2O processing. Radio analytical determinations were performed by gamma spectrometry using a high-purity germanium detector. This technique has proven useful in identifying local radioactive pollution. This type of pollution was consistently detected throughout the year, with several increases associated with authorized discharges from hospitals. Finally, we examined the radiation dose that workers are exposed to due to the presence of 131I in the sludge. We found inhalation risk to be negligible, with external radiation as the main source of exposure to 131I.

Carcinus maenas is an invasive species of recognised economical and ecological importance in which mercury accumulation could be a pathway for bioamplification through food webs. Little information is available about differential accumulation between crab sexes and morphotypes. Taking this in mind, a set of different industrial discharge scenarios were investigated in 96-h laboratory experiments for assessing the accumulation of inorganic mercury from contaminated seawater into the tissues of C. maenas. Three groups of crabs (green males, green and red females) where exposed to 5, 50 and 250 μg Hg L−1. Differences among sexes, morphotypes and tissues were detected, depending on the mercury concentration. The muscle did not show differential accumulation between sexes or morphotypes. For mercury-exposed crabs, the contaminant was accumulated preferably in the gills (more than 75%) while, in control experiments, it was in the internal organs, muscle and hepatopancreas, and gills corresponded to less than 31% of the total mercury quantified. The different tissue contamination seems dependent on the major pathway of exposure, diet or water. Mercury accumulation by the crab was a rapid process and could represent a risk for the environment only after 96 h. In a scenario of a discharge point of 250 μg L−1, all tissues of crabs exposed would attain a very close, or even exceed the threshold concentration value for human consumption (0.5 mg kg−1).

Coal carbonization by-products contain up to 10,000 aliphatic and aromatic compounds. Many of them show toxic, mutagenic, and carcinogenic character. In this study, we examined 51 pure bacterial cultures of their ability of coal tar constituent biodegradation. Bacterial cultures were isolated from both explosives and coal tar-contaminated areas. Among all of the investigated strains, 19 showed biodegradative activity. One of the isolates degraded 40% of the substrate in 14 days at a temperature of 15°C. The most active strain was identified by both classic and 16S ribosomal DNA sequencing methods and designated Rhodococcus erythropolis B10. The biodegradation of coal tar constituents, performed by identified strain, was assessed by GC/MS technique. The comparison of samples analyzed by GC/MS before and after biodegradation indicated high degradative potential of the chosen strain. It was able to degrade n-paraffins, n-olefins, benzene, alkylbenzenes, cadalene, and other PAHs, as well as recalcitrant heterocyclic compounds dibenzofuran and its methyl-substituted derivative. The B10 strain isolated and tested in this research shows promising possibilities to be used in field conditions. The biodegradation experiments indicated that satisfactory results may be obtained even in pure bacterial cultures.

Amycolatopsis tucumanensis, a recently recognized novel species showed remarkable copper resistance as well as efficient Specific Cupric Reductase Activity (SRACu) in both, copper adapted and non-adapted cells, under different temperatures of incubation. Its copper resistance strength was highlighted against other metal-resistant actinobacteria (Streptomyces sp. AB5A) and sensitive strains (Amycolatopsis eurytherma and Streptomyces coelicolor). Pre-adapted cells of A. tucumanensis displayed values of SRACu, on average, 65% higher than those obtained from non-adapted cells. In addition, preadaptation of A. tucumanensis improved the rate of Cu(II) reduction which was approximately, two-, seven- and ninefold higher than pre-adapted cells from Streptomyces sp. AB5A, A. eurytherma and S. coelicolor, respectively. A. tucumanensis showed the highest levels of SRACu at all temperatures and also the highest copper resistance profile, suggesting that these two abilities may be in close relationship. This ostensible versatility, related to the temperature, of adapted cells from A. tucumanensis might support the application of this strain under different bioremediation conditions. To our knowledge this is the first time that cupric reductase activity was demonstrated within the genus Amycolatopsis.

This study evaluated the effectiveness of a novel adsorbent (Fe(III)-AM-PGMACell), Iron(III)-coordinated amino-functionalized poly(glycidyl methacrylate)-grafted cellulose for the adsorption of arsenic(V) from aqueous solutions. The Fe(III)-AM-PGMACell was prepared through graft copolymerization of glycidyl methacrylate (GMA) onto cellulose (Cell) in the presence of N,N′-methylenebisacrylamide (MBA) as a cross linker using benzoyl peroxide initiator, followed by treatment with ethylenediamine and ferric chloride in the presence of HCl. Batch experiments were performed to evaluate the adsorption efficiency of Fe(III)-AM-PGMACell towards As(V) ions. The contact time to attain equilibrium and the optimum pH were 90 min and 6.0, respectively. More than 99.0% adsorption was achieved from an initial concentration of 25.0 mg/L. A two-step pseudo-first-order kinetic model agreed well with the dynamic behavior for the adsorption process. Equilibrium data fitted well with Sips isotherm model with maximum adsorption capacity of 78.8 mg/g at 30°C. The desorption of As(V) was achieved over 98.0% with 0.1 M NaCl solution.

This study assessed the foliar uptake of 15N-labelled nitrogen (N) originating from wet deposition along with leaf surface conditions, measured by wettability and water storage capacity. Foliar 15N uptake was measured on saplings of silver birch, European beech, pedunculate oak and Scots pine and the effect of nitrogen form (NH4 + or NO3 −), NH4 + to NO3 − ratio and leaf phenology on this N uptake was assessed. Next to this, leaf wettability and water storage capacity were determined for each tree species and phenological stage, and the relationship with 15NH4 + and 15NO3 − uptake was examined. Uptake rates were on average five times higher (p < 0.05) for NH4 + than for NO3 − and four times higher for deciduous species than for Scots pine. Developing leaves showed lower uptake than fully developed and senescent leaves, but this effect was tree species dependent. The applied NH4 + to NO3 − ratio did only affect the amount of N uptake by senescent leaves. The negative correlation between measured leaf contact angles and foliar N uptake demonstrates that the observed effects of tree species and phenological stage are related to differences in leaf wettability and not to water storage capacity.

Aqueous natural organic matter (NOM) impacted by two contrasting human impacts was analyzed using by multiresponse fluorescence, decoupled with the resolution routine PARAFAC. The first site is Chalk River, Ontario, Canada, near a pit formerly used to dispose low-level wastes. The second site is the Grand River in Cambridge, south-central Ontario, which is impacted by urban activities and agriculture. Our analysis included raw water, plus fractions from ultrafiltration and solid-phase extraction (SPE). The fluorescence spectra of the NOM, resolved with PARAFAC, showed three common features: humic-like components, at excitation/emission wavelengths 325-350/450-475 nm, fulvic-like components at 325/380-420 nm and protein-like components, at 275/300 nm. Ultrafiltration revealed that most of the NOM comprised fine material below 5,000 Da cut-off (<4% of the total) in the urban-impacted sites and the clean site at Chalk River, but the colloidal fraction (larger than 5,000 Da) was substantially higher in the contaminated water, with ∼18-26% of the total. The protein-like components in the contaminated Chalk River water were affected by ultrafiltration, but less so in the clean Chalk River sample and the urban-impacted waters. SPE preferentially removed the protein-like component in the contaminated Chalk River water (typically 89-95% signal decrease), but had a limited effect on humic- and fulvic-like components elsewhere. In conclusion, multiresponse fluorescence provided new information on the NOM quality from two contrasting sites, aided by ultrafiltration and SPE. These results are consistent with the in situ production of NOM in the Chalk River contaminated site, and natural production at the other sites.