Perfluorinated chemicals (PFCs) are extremely persistent and have been found extensively in the environment and wildlife. Oceans are the final sink for many persistent organic pollutants (POPs) including PFCs. However, to date, there has been a lack of studies that investigated the environmental consequences of PFCs on marine organisms. To fill in this gap, environmental toxicity of two dominant PFCs, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), was examined in a sentinel species, green mussel Perna viridis, using a series of biomarkers corresponding to different biological levels (molecular, cellular, and physiological). Correlations among these biomarkers were also investigated. The results showed that the tested compounds can induce a series adverse effect at different biological levels, including oxidative stress, DNA damage, membrane instability, suppressed filtration rate, and reduced body weight. Correlation analysis revealed that excess production of reactive oxygen species could be the major toxic pathway. An indirect mode of toxic action was also explored where adverse impacts could be secondary effects of PFC exposure. The joint analysis of biomarkers from multiple biological levels resulted in a comprehensive understanding of how PFC exposure can influence the health of organisms. The correlations of these biomarkers also provided a new perspective of the ecological consequences of PFCs.

Treated and untreated rice straw extensively exists in the soil. In order to elucidate its possible effect on the fate of organic pollutants, sorption of pyrene by rice straw and its main constituents (lignin, cellulose, and hemi-cellulose) were studied, as single solute and in the presence of other co-existing organic pollutants, phenanthrene (Phen), benzo[a]pyrene (BaP), phenol, and pentachlorophenol (PCP). Pyrene showed the greatest sorption on lignin with greater aromaticity and smaller polarity, and the sorption coefficient was almost two orders of magnitude greater than those on cellulose and hemi-cellulose. Bi-solute sorption results showed that Phen, BaP and PCP exhibited apparent competitive sorption with pyrene on the four sorbents; while the existence of phenol promoted the sorption of pyrene on rice straw and lignin but inhibited the sorption on cellulose and hemi-cellulose. For the two polycyclic aromatic hydrocarbon (PAH) co-solutes and PCP, hydrophobicity and molecular size played important roles in competition, suggesting the direct competition for hydrophobic sorption sites and pore blockage mechanisms. In contrast, the polar co-solute, phenol showed different effects on pyrene sorption onto the four sorbents, suggesting that multiple interactions between polar organic compounds and sorbents are involved in the sorption.

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.

Aquatic weed Myriophyllum spicatum L. is one of the most invasive water plants known. In many countries, it is usually harvested and landfilled, where aerobic and anaerobic decomposition takes place. In this research, the kinetic, equilibrium, and desorption studies of biosorption of Pb(II), Cu(II), Cd(II), Ni(II), and Zn(II) ions onto compost of M. spicatum were investigated in batch experiments. Biosorbent was characterized by scaning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM analysis showed that ion exchange between divalent cations Ca(II) and selected metals takes place. The results of FTIR exposed that carbonyl, carboxyl, hydroxyl, and phenyl groups are main binding sites for those heavy metal ions. The rate of adsorption of the five heavy metals was fast, which achieved equilibrium in 40 min, and followed the pseudo-second-order model well. Langmuir, Freundlich, and Sips equilibrium adsorption models were studied, and Sips isotherm gave the best fit for experimental data. Desorption by 0.1 M HNO₃did not fully recover the metals sorbed onto the compost, indicating that reusing this material as biosorbent is not possible. Furthermore, the use of spent biosorbent as a soil fertilizer is proposed.

US National Ambient Air Quality Standards (NAAQS) are based on quantitative linkages between ambient air concentrations and an effects indicator. Critical loads (CLs) can provide quantitative information on safe levels of atmospheric deposition to aquatic systems, but CLs cannot be directly used in the NAAQS context because they are not expressed in terms of atmospheric concentrations. Here, we describe the aquatic acidification index (AAI) model that incorporates CL concepts and relates atmospheric nitrogen and sulfur concentrations to an acid neutralizing capacity (ANC) effects indicator (Fig. 1). The AAI estimates the potential surface water ANC associated with a set of atmospheric concentrations of nitrogen and sulfur and a region's biogeochemical and hydrological attributes by combining steady-state CL modeling with air quality modeling outputs. Initial applications of the AAI model yielded results consistent with well-recognized spatial patterns of acid-sensitive aquatic systems. Furthermore, the response of AAI predictions to future year changes in NO ₓ and SO ₓ emissions suggest that planned national emission reduction strategies designed to reduce ozone and particulate matter air pollution will produce increases in surface water ANC.

The influence of structure on degradation of five halogenated phenols (XPs) by UV/H₂O₂process was investigated. The combined influence of type or number of substituents and UV/H₂O₂process parameters (pH and [H₂O₂]) on the degradation kinetics of 2-fluorophenol (2-FP), 2-chlorophenol (2-CP), 2-bromophenol (2-BP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) was studied using modified miscellaneous 3³full factorial design and response surface modeling (RSM). Studied XPs obey first-order degradation kinetics within the investigated range of process parameters. Determined degradation rate constants (kₒbₛ) were correlated with process and structural parameters by the quadratic polynomial models. Analysis of variance (ANOVA) demonstrated RSM models’ accuracy and showed that, in addition to pH and [H₂O₂], model terms related with the pollutant structure are highly influential. kₒbₛof mono-XPs follow the decreasing order 2-FP, 2-CP, and 2-BP, while CPs follow the decreasing order 2-CP, 2,4-DCP, and 2,4,6-TCP. Biodegradability (biochemical oxygen demand (BOD)₅/chemical oxygen demand (COD)) and toxicity (TU) were evaluated prior to the treatment and at the reference time intervals. The observed differences are correlated with the structural characteristics of studied XPs.

The potential of the activated carbon prepared from the empty fruit bunch of oil palm wastes to remove bisphenol A (BPA) from aqueous media was investigated. The experiments were performed by varying the contact time, activated carbon dose, initial BPA concentration, and pH of the solution. The Langmuir, Freundlich, and Temkin isotherm models were employed to discuss the adsorption behavior. The equilibrium data were perfectly represented by the Langmuir isotherm with R²of 0.9985. The maximum monolayer adsorption capacity of the activated carbon was found to be 41.98 mg/g. Kinetic studies indicated that the adsorption process followed the pseudo-second-order kinetic with a rate constant of 0.3 × 10⁻³/min. The activated carbon was characterized by means of Fourier transform infrared spectrometry, Brunauer–Emmett–Teller, and field emission scanning electron microscopy analyses. The results of the present study indicate that the activated carbon prepared from the empty fruit bunch is a promising candidate as a low-cost bio-adsorbent for the removal of BPA from aqueous solution.

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.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are pollutants of significant global concern, and China is one of the main dioxin-emitting countries in the world. Facing increasing dioxin concentrations in the environment, the Chinese government set a mandatory goal of 10 % reduction in the rate of emission intensity by 2015 in an attempt to reduce dioxin emissions. In the study presented here, we estimated the outputs (or waste disposal capacities) of the four key dioxin-emitting industries in China in 2015. We then estimated that the total amount of dioxins released from these four industries was approximately 8.0 kg toxic equivalent (TEQ)/year. These results indicate that dioxin emissions in China have not decreased under the current plan, and the plan needs to be adjusted. A goal for a decrease in the total dioxin emissions in China is proposed, and several policies and measures aimed at allowing the target dioxin emission decrease to be achieved are recommended.

Sulfur hexafluoride (SF₆) has been evaluated by the Intergovernmental Panel on Climate Change (IPCC) as the substance with the highest global warming index. Because of its superior insulating and arc clearing capacities, it is commonly used as an insulator in electrical machines. SF₆waste products form in the process of storing, maintaining, and repairing the machines. SF₆emitted into the atmosphere remains for 3,200 years, causing global warming. Release into the mesosphere leads to photolysis and creation of highly toxic and corrosive by-products. A review of the literature related to the retrieval and separation of SF₆using a separating membrane indicates that research on the permeability of the separating membrane material is lacking. Additionally, research on the concentrations of the SF₆waste products and the separation/retrieval with operating conditions with optimal energy efficiency is only in the initial stages. Therefore, this research assessed the permeability of commercialized separation membranes polysulfone (PSf), polycarbonate (PC), and polyimide (PI) using the gases SF₆and N₂. Using an SF₆/N₂mixture with the same concentration as the SF₆waste products, we studied the separation and retrieval capacities of PSf, PC, and PI separation membranes under varying operating conditions. The permeability tests showed that the selective permeability of N₂/SF₆is highest for the PI membrane and lowest for the PC membrane. When the concentrations of SF₆retrieved from the mixture separation process were compared, the PC membrane was found to be the highest, with 95.6 % at 0.5 MPa. The retrieval percentage of SF₆was highest for PSf, with 97.8 % at an operating pressure of 0.3 MPa and a waste production of 150 cm³/min. The retrieval rates and retrieval failure rates have an inverse relationship. In total, 99 % of the supply of SF₆was identified via the retrieval rates and retrieval failure rates, so it could be confirmed that the separation of the SF₆/N₂mixture using a macromolecular hollow fiber separation membrane works properly.