A study on the surface modification of uncontaminated sediment dredged for new port development with surfactant was performed, and the effectiveness of surface modified sediment for in-situ capping to control pollutant (N, P) release from the contaminated coastal sediments into seawater was also investigated. From this experiment, the adsorbed amount of surfactants on the surface of sediment particles was increased with the increase in the surfactant concentration. A more feasible method for the sediment modification with surfactants was mechanical shaking for 3 h, compared to sonication for 30 min or microwave radiation for 3 min. The adsorption capacities of the sediments modified with cationic surfactant (hexadecyltrimethylammonium bromide [HDTMA]) were 40 mg g⁻¹ for ammonia-nitrogen, 16 mg g⁻¹ for nitrate-nitrogen, 31 mg g⁻¹ for phosphorus, which are higher those of the sediment modified with anionic (SDS) and nonionic surfactants (TX-100). The capping layer with the sediment modified with HDTMA in column experiment was effective for inhibiting the release of nitrogen and phosphorus from the contaminated sediment into overlying seawater, indicating that the cationic surfactant modified sediment is reusable as a good in-situ capping material for contaminated coastal sediment.

The Tubarão River rises in Santa Catarina, Brazil, and has been historically affected by coal mining activities around its springhead. To evaluate its water conditions, an investigation regarding a possible decontamination gradient associated with the increased river flow toward the estuary, as well as the influence of seasonality over this gradient was performed through a series of biomarkers (vitellogenin, comet assay, lipid peroxidation, protein carbonylation, gluthatione, gluthatione S-transferase, acetylcholinesterase, light microscopy in liver, and scanning electron microscopy in gills) and chemical analysis (polycyclic aromatic hydrocarbons (PAHs) in bile and metal analysis in sediment) in the cichlid Geophagus brasiliensis. Two collections (summer and winter) were made in four distinct sites along the river, while sediments were sampled between those seasons. As expected, the contamination linked exclusively to mining activities was not observed, possibly due to punctual inputs of contaminants. The decontamination gradient was not observed, although seasonality seemed to have a critical role in the responses of biomarkers and availability of contaminants. In the summer, the fish presented higher histopathological damages and lower concentrations of PAHs, while in the winter they showed both higher genetic damage and accumulation of PAHs. The Tubarão suffers impacts from diverse activities, representing health risks for wild and human populations.

The incineration fly ash (IFA), molten fly ash (MFA), thermal power plant fly ash (TPP-FA), and nonferrous metal processing plant ash (MMA) have been screened in terms of the following rare-termed metal contents: B, Ce, Co, Dy, Eu, Ga, Gd, Hf, In, Li, Lu, Mn, Nb, Nd, Ni, Pr, Rb, Sb, Se, Sm, Sr, Ta, Tb, Te, Ti, Tm, V, W, Y, and Yb. The pseudo-potential for recycling of the waste ashes, as compared to the cumulative concentration in the crust (mg kg⁻¹), was determined as follows: MMA > IFA > MFA > TPP-FA. The comparison with the crude ore contents indicates that the MMA is the best resource for reprocessing. The recovery of the target metals using aminopolycarboxylate chelants (APCs) has been attempted at varying experimental conditions and ultrasound-induced environment. A better APC-induced extraction yield can be achieved at 0.10 mol L⁻¹ concentration of chelant, or if the system temperature was maintained between 60 to 80 °C. Nevertheless, the mechanochemical reaction induced by the ultrasound irradiation has been, so far, the better option for rare metal dissolution with chelants as it can be conducted at a minimum chelant concentration (0.01 mol L⁻¹) and at room temperature (25 ± 0.5 °C).

In order to determine the pollution sources in a suburban area and identify the main direction of their origin, PM₂.₅ was collected with samplers coupled with a wind select sensor and then subjected to Positive Matrix Factorization (PMF) analysis. In each sample, soluble ions, organic carbon, elemental carbon, levoglucosan, metals, and Polycyclic Aromatic Hydrocarbons (PAHs) were determined. PMF results identified six main sources affecting the area: natural gas home appliances, motor vehicles, regional transport, biomass combustion, manufacturing activities, and secondary aerosol. The connection of factor temporal trends with other parameters (i.e., temperature, PM₂.₅ concentration, and photochemical processes) confirms factor attributions. PMF analysis indicated that the main source of PM₂.₅ in the area is secondary aerosol. This should be mainly due to regional contributions, owing to both the secondary nature of the source itself and the higher concentration registered in inland air masses. The motor vehicle emission source contribution is also important. This source likely has a prevalent local origin. The most toxic determined components, i.e., PAHs, Cd, Pb, and Ni, are mainly due to vehicular traffic. Even if this is not the main source in the study area, it is the one of greatest concern. The application of PMF analysis to PM₂.₅ collected with this new sampling technique made it possible to obtain more detailed results on the sources affecting the area compared to a classical PMF analysis.

In allocating the waste load of a river basin, the first priority is to achieve a given water quality goal for that river by utilizing several water quality management methods. Minimizing the waste load abatement cost within the river basin through appropriate, efficient water quality management is an important aspect of this process. In the past, it was common to concentrate on economic factors when constructing a waste load allocation (WLA) model. However, environmental resources (e.g., sub-basin area, population, wastewater flow, etc.) vary in each region of a river, and the fairness in the distribution of the treatment efforts among waste dischargers must be considered. The WLA model in this study was constructed as a multi-objective optimization problem and was established to achieve the economic goal of minimizing waste load abatement and to consider the inequality among waste dischargers. Two types of inequality were introduced into the WLA model. The first type is the inequality in the waste load discharge regarding the environmental resources in each region was computed with the environmental resource-based Gini coefficient. The second type of inequality is the fairness in the distribution of the treatment efforts among waste dischargers. The suitability of this WLA model was verified with its application in a heavily polluted total maximum daily load subject river in South Korea. Furthermore, Pareto-optimal solutions drawn from the multi-objective genetic algorithm were analyzed to infer the least cost solution, the least inequality solution, and the compromise solutions and to verify critical pollution sources.

In this study, we simulated heterotrophic CO₂(Rh) fluxes at six European peatland sites using the ECOSSE model and compared them to estimates of Rh made from eddy covariance (EC) measurements. The sites are spread over four countries with different climates, vegetation and management. Annual Rh from the different sites ranged from 110 to 540 g C m⁻². The maximum annual Rh occurred when the water table (WT) level was between −10 and −25 cm and the air temperature was above 6.2 °C. The model successfully simulated seasonal trends for the majority of the sites. Regression relationships (r²) between the EC-derived and simulated Rh ranged from 0.28 to 0.76, and the root mean square error and relative error were small, revealing an acceptable fit. The overall relative deviation value between annual EC-derived and simulated Rh was small (−1 %) and model efficiency ranges across sites from −0.25 to +0.41. Sensitivity analysis highlighted that increasing temperature, decreasing precipitation and lowering WT depth could significantly increase Rh from soils. Thus, management which lowers the WT could significantly increase anthropogenic CO₂, so from a carbon emissions perspective, it should be avoided. The results presented here demonstrate a robust basis for further application of the ECOSSE model to assess the impacts of future land management interventions on peatland carbon emissions and to help guide best practice land management decisions.

Surface mining for coal is responsible for widespread degradation of water resources and aquatic ecosystems in the Appalachian Region, USA. Because native topsoils are typically not retained on Appalachian mined sites, mine soils are usually composed of crushed overburden. This overburden tends to contribute high salinity loads to downstream aquatic systems. Also, loss of transpiration from forests and reduced infiltration associated with conventional reclamation procedures lead to altered water budgeting and stream morphology. To investigate the influence of the geologic composition of this overburden on water quality and tree growth, a series of experimental plots were constructed on a reclaimed surface mine site in eastern Kentucky, USA, in 2005. Treatments included unweathered GRAY sandstone, weathered BROWN sandstone, and MIXED sandstones and shale spoils. Plots were composed of end-dumped, uncompacted spoils and were designed to drain interflow through data acquisition stations for sampling purposes. Most water chemical parameters had stabilized across all treatments by 9 years after spoil placement. Discharge volume was not different among treatment types through the first 3 years after placement. However, 9 years after placement, seasonal variation in discharge on BROWN is more extreme than that on MIXED or GRAY. In addition, planted tree growth on BROWN has drastically outpaced growth on GRAY or MIXED, suggesting that evapotranspiration may be influencing seasonal variation in water discharged from BROWN. These results suggest that placement of brown weathered spoils when soil substitutes are required may lessen hydrologic impacts via improved tree growth and water utilization on surface-mined sites in Appalachia.

Reduction in the concentration of pharmaceuticals present in wastewater has been attributed to sorption and biodegradation. However, the contribution of these processes has not been fully characterized. Previous studies have reported varying effects of solution pH and concentration on sorption behavior of pharmaceuticals in different absorbents including activated carbon waste and zeolites. Here we report the pH and concentration effect on sorption of two common anti-inflammatory drugs, viz., ibuprofen and naproxen, on suspended solids in simulated domestic wastewater (SDWW). Batch experiments were conducted at various pH levels, viz., 3.5, 6.5, 7.5, and 8.5, and concentration, viz., 125, 250, 500, 750, and 1,000 μg L⁻¹. The results showed that both ibuprofen and naproxen have higher sorption at lower pH values and at higher concentration. It was found that the data were comparatively well fitted to the Redlich–Peterson isotherm. The study revealed that both ibuprofen and naproxen can be removed from wastewater by the sorption process achieved by lowering the pH to values lower than pKₐand maintaining the concentration at an optimal value.

Mutual sorption interactions between heavy metals, humic acids and fungi were evaluated in this article. While the relative amount of sorbed As(V), Sb(III) and Pb(II) slightly decreased or remained unchanged, the sorption capacity of Zn(II) increased significantly with increasing amounts of immobilized humic acids in the Ca-alginate beads. Therefore, zinc is most likely preferentially sorbed to functional groups provided by humic acids rather than carboxyl or hydroxyl groups of alginate, with an optimum pH for uptake between 4 and 6. Nevertheless, the removal efficiency of metal(loid)s by unmodified Ca-alginate beads or those with humic acids modification was highest for Pb(II), at up to 93.5 %. The pH value also affects humic acids sorption properties on microbial surfaces. While the highest humic acids sorption capacity of mycelial pellets prepared from Aspergillus niger occurred at pH 8.5 (231 mg g⁻¹), the pelletized Aspergillus clavatus biomass was more effective in acidic solution and 199 mg g⁻¹was recorded there at pH 5.5. The effect of mutual interactions between humic acids and mycelial pellets on Zn(II) immobilization indicates that zinc affinity is higher for the fungal surface than for humic acids which do not supply sufficient active sorption sites for zinc. This resulted in less sorption capacity of the mycelial pellets modified with humic acids compared to the unmodified biomass.

Phosphorus (P) loss from non-point sources is a main cause of freshwater eutrophication in agricultural regions. Knowledge-based watershed management plans, aimed at reducing the diffuse flux of phosphorus from specific land-use and site characteristics to freshwater resources, are needed in order to curb eutrophication in agriculture regions. In this context, the use of a phosphorus index provides a simple and practical method for identifying hot-spot source areas and to estimate their potential for contributing a flux of P to the surface waters. However, as a semi-quantitative tool, the P index is usually difficult to validate due to inadequate data representation relative to large spatial and temporal variation in P fluxes. An amended P index scheme is therefore developed and validated, based on comprehensive synoptic soil study and stream water monitoring as well as a previous study that had applied the former P index in the studied watershed in northern China (Zhang et al. 2003). The amendments include the use of data from the individual village units (mean area, ca. 30.6 ha), use of the degree of P saturation (DPS) in the source factor scheme, adoption of flow length factor and modified water course erosion factor into the P transportation scheme, and an adjustment of the organization structure of the P index scheme. The validation of the amended P schemes was performed by comparing the modeled average P index values with the corresponding measured P fluxes for 12 different sub-catchments. The results indicate an improved precision in the simulated potential for P loss using the refined P index scheme. Measured fluxes of total P (r = 0.825), particulate P (r = 0.867), and less-studied yet more relevant dissolved P (r = 0.627) all showed significant correlations with the modeled P index values in the amended P scheme. The primary direct finding of the current research is that the areas with close proximity to rivers and the reservoir, as well agricultural land around villages, are found to be the main hot-spot sources for P loss to the reservoir.