Submerged harbor steel structures often employ cathodic protection using galvanic anodes to guard against corrosion. A laboratory experiment, with three different cathodic protection configurations by galvanic aluminum-based anodes, was performed to evaluate the potential metal transfer from the anodic alloy dissolution into the surrounding marine water. The anode dissolution rate is proportional to the imposed current demands and induced a significant Al, In, and Zn transfer in the dissolved and particulate fractions of the corrosion product layers covering the anode surface. These layers were poorly adherent, even under low hydrodynamic conditions. Consequently, at the anode vicinity, the suspended particle matter and dissolved fraction of surrounding marine waters showed strong enrichments in Al and Zn, respectively, the values of which could potentially affect the adjacent biota. After the anode activation period, however, the metal inputs from galvanic anode dissolution are rapidly diluted by seawater renewal. At regional scale, these metal fluxes should be negligible compared to river and wastewater fluxes. These results also showed that it is difficult to assess the impact of the anode dissolution on the concentrations of metals in the natural environment, especially for metals included in trace amounts in the anode alloy (i.e., Cu, Fe, In, Mn, and Si) in the aquatic compartment.

Surface water bodies can be impaired by turbidity and excessive sediment loading due to urban development, construction activities, and agricultural practices. Turbidity has been considered as a proxy for evaluating water quality, aquatic habitat, and aesthetic impairments in surface waters. The US Environment Protection Agency (USEPA) has listed turbidity and sediment as major pollutants for construction site effluent. Recently proposed USEPA regulations for construction site runoff led to increased interest in methods to predict turbidity in runoff based on parameters that are more commonly predicted in runoff–erosion models. In this study, a turbidity prediction methodology that can be easily incorporated into existing runoff–erosion models has been developed using fractions of sand, silt, and clay plus suspended sediment concentration of eight parent soils from locations in Oklahoma and South Carolina, USA.

Here, we report on the ability of two different water treatment residues, a Fe-based (Fe-WTR) and an Al-based (Al-WTR) ones, to accumulate Cd(II) and Zn(II) from aqueous solutions at different pH values (pH 4.5, 5.5, and 7.0). Fe-WTR showed a greater Zn(II) and Cd(II) sorption capacity than Al-WTR at all the pH values investigated, in particular at pH 7.0 (e.g., ∼0.200 and ∼0.100 mmol g⁻¹ of Me(II) sorbed by Fe- and Al-WTR at pH 7.0, respectively). The greater capacity of the Fe-WTR to accumulate Me(II) seems to be linked to its higher content of iron and manganese ions and to its higher CEC value compared to Al-WTR. The role of the inorganic and organic fractions of WTRs in metal sorption was also assessed. A higher affinity of Cd(II) with respect to Zn(II) toward functional groups of the organic matter of both WTRs was observed, while Zn(II) showed a stronger association with the inorganic phases. The sorption of both metal ions appeared mainly governed by the formation of inner-sphere surface complexes with the inorganic and organic phases of WTRs, as suggested by the sequential extraction data.

Pig farms have achieved importance in the last few decades from the perspective of environment protection as a consequence of the intensive rearing systems in livestock production. Ammonia (NH₃) and greenhouse gases (GHG), such as methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O), are emitted from slurry storage at farm prior to land application, but little is known about these losses under on-farm conditions in Spain. This study assessed the influence of management and environmental parameters on NH₃ and GHG emissions from slurry storage in spring and autumn. Gas emissions were measured in a commercial pig-fattening farm from two lagoons (1000 and 768 m³ capacity, respectively) during 30 days by the floating dynamic chamber system in spring and autumn 2011 (average temperature 19 and 9 °C, respectively). Low NH₃ and CH₄ emissions were registered in spring (range 10–406 and 3–17 mg m⁻² min⁻¹, respectively) probably as a result of low pH values of stored slurry (6.5 to 7.0) and rainfall. High variability on NH₃, CH₄, and CO₂ emissions was observed as a result of differences in temperature and rainfall. No NH₃ emission and low CH₄ and CO₂ emissions were observed in autumn (average 1.2 ± 0.9 and 27 ± 22 mg m⁻² min⁻¹, respectively). Slurry loading operations increased NH₃ losses from storage.

Upland swamps of the Blue Mountains are unique and legislatively protected peat swamp communities. This study investigated water chemistry of surface waters from seven Blue Mountains Upland Swamps (BMUS), four within urbanised catchments and three from naturally vegetated catchments. The purpose of the study was to investigate any ionic contamination from urban development. Water chemistry of non-urban BMUS was acidic (mean pH 4.7) and dilute (mean EC 26.6 μS/cm) and dominated by sodium and chloride ions with most other major ions at low concentrations, often below detection limits. In contrast, urban BMUS had higher pH (mean 6.6) and salinity (mean 153.9 μS/cm) and were dominated by calcium and bicarbonate ions. The results of this study support the hypothesis that urban concrete contamination is modifying the geochemistry of urban BMUS. Further research is required to investigate ecological implications of the contamination and also to explore measures to protect such sensitive wetlands of high conservation value from urban development.

Alkyl polyglucosides, due to their low toxicity and environmental compatibility, could be used in biodegradation of hydrophobic compounds. In this study, the influence of Lutensol GD 70 on the cell hydrophobicity and zeta potential was measured. The particle size distribution and surfactant biodegradation were also investigated. Microbacterium sp. strain E19, Pseudomonas stutzeri strain 9, and the same strain cultivated in stress conditions were used in studies. Adding surfactant to the diesel oil system resulted in an increase of the cell surface hydrophobicity and the formation of cell aggregates (a high polydispersity index). The correlation between cell hydrophobicity and zeta potential in examined samples was not found. The results showed a significant influence of Lutensol GD 70 on the changes in cell surface properties. Moreover, a high biodegradation of a surfactant (over 50 %) by tested strains was observed. The biodegradation of Lutensol GD 70 depends on the length of both polar and nonpolar chains. A long-term contact with diesel oil of stressed strain modifies not only cell surface properties but also its ability to a surfactant biodegradation.

Industrial production of manganese/silicon ore has generated a large number of tailing wastes which are difficult to dispose. A new method treating coking wastewater was proposed using the manganese/silicon tailing waste and demonstrated with good performances: the chemical oxygen demand (COD) removal rate was around 60 % without pH and temperature adjustment, with a reasonable reaction time of 2.5 h and tailing dosage of 0.2 g/L; while phenylamine was eliminated with a removal rate as high as 99 and 61.6 % for synthetic and real coking wastewater, respectively. Experimental results indicated that the removal of organic pollutants was mainly realized through chemical adsorption and/or oxidation by oxide components inside the tailing, rather than by physical adsorption. Operational parameters such as tailing dosage, reaction time, and temperature were optimized. Acid conditions were found to be favorable to remove the selected model organic pollutants, i.e., volatile phenols and phenylamine. Fortunately, the optimistic wastewater pH for COD removal was found to be around 7.0, right within the range of influent pH for real coking wastewater. The new method can treat coking wastewater and reuse mining tailing wastes simultaneously.

Microbial Cr(VI) reduction is a significant process in detoxification of Cr(VI) pollution. In this study, a new Cr(VI)-reducing bacterial strain, Cr-4, was isolated from soil around the chromium-containing slag. The analysis of the 16S ribosomal RNA (rRNA) gene sequence revealed that the newly isolated strain was closely related to Bacillus anthracis. The response to Cr(VI) stress and reduction capacity of the isolate were investigated. Cell growth decreased with the increase of Cr(VI) concentration. Cell morphology varied and cell growth was inhibited remarkably in the presence of 125 mg/L Cr(VI). The strain grew well and removed Cr(VI) effectively at a Cr(VI) concentration lower than 50 mg/L. Cr(VI)-reducing activity was inhibited by Zn²⁺, while significantly stimulated by Cu²⁺. The activity of Cr(VI) reduction by cell-free extract was demonstrated. Total chromium analysis and the energy-dispersive X-ray analysis (EDAX) spectrum revealed that Cr(VI) removal was caused mainly by microbial reduction rather than by biosorption and the main part of the reduced Cr(III) existed as soluble form in solutions.

Deterioration of natural water resources due to runoff from agricultural land is a major problem in the US Great Plains. Changes in earth climate can create heavy storms and alter precipitation patterns which would affect the element concentrations in runoff. A 2-year study (dry and wet years) was conducted to assess the impact of annual precipitation on element concentrations in runoff from soils and element loadings to Salt Creek in the Roca watershed, NE. Both dissolved and sediment-associated forms of five elements (Al, Fe, Mn, Cu, and Zn) were determined in runoff. The amount of dissolved element in runoff during the wet year was greater than the dry year. Except for Zn, the total amount of element associated with sediment was greater than that found in dissolved form. The Mehlich3 extraction was applied to determine the reactive fraction of element in sediment. A small fraction of element associated with sediment was in reactive form, ranging from 1 to 33 % of the total element content. The sum of both the reactive fraction of element in sediment and amount of element dissolved in water were used to calculate the total bioactive element concentration (BEC) in runoff. During the dry year, the total BEC in runoff was 424, 349, 387, 5.2, and 26.8 μg/L for Al, Fe, Mn, Cu, and Zn, respectively. The corresponding total BEC during the wet year was 622, 479, 114, 3.7, and 19.8 μg/L for Al, Fe, Mn, Cu, and Zn, respectively. Further, the bioactive element loading (BEL) into Salt Creek was greater during the wet year than the dry year. Aluminum, Fe, and Mn contributed to the greatest BEL into the surface water body while Zn and Cu had the least contribution. We concluded that greater precipitation during the wet year would increase the negative impact of runoff from soils and BEL to surface water systems in the US Great Plains.

The degradation of hexachlorobenzene (HCB) is of great concern and attracts considerable scientific and regulatory interests, due to the high toxicity, great bioaccumulation, and persistence of HCB in the environment. However, in the real HCB-contaminated soil, the effect of coexisting chlorobenzene congeners on the degradation capacity of HCB is poorly known. In this work, the anaerobic degradation behaviors of three coexisting chlorobenzene congeners pentachlorobenzene (PeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB), and 1,2,4-trichlorobenzene (1,2,4-TCB) and the influence of initial pH and reaction temperature on the dechlorination of HCB in HCB-contaminated soil from the dye plant were studied. The amount and extent of accumulated coexisting chlorobenzenes was analyzed under different environmental conditions. The results indicate that the concentrations of three coexisting chlorobenzene congeners change in the form of wave. The anaerobic degradation activity of HCB is reduced due to the feedback inhibition caused by accumulation of coexisting chlorobenzene congeners, and the feedback inhibition varies from environmental conditions.