Long-lived, upper trophic level marine mammals are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Internal tissues may accumulate and mobilize POP compounds at different rates related to the body condition of the animal and the chemical characteristics of individual POP compounds; however, collection of samples from multiple tissues is a major challenge to ecotoxicology studies of free-ranging marine mammals and the ability to predict POP concentrations in one tissue from another tissue remains rare. Northern elephant seals (Mirounga angustirostris) forage on mesopelagic fish and squid for months at a time in the northeastern Pacific Ocean, interspersed with two periods of fasting on land, which results in dramatic seasonal fluctuations in body condition. Using northern elephant seals, we examined commonly studied tissues in mammalian toxicology to describe relationships and determine predictive equations among tissues for a suite of POP compounds, including ΣDDTs, ΣPCBs, Σchlordanes, and ΣPBDEs. We collected paired blubber (inner and outer) and blood serum samples from adult female and male seals in 2012 and 2013 at Año Nuevo State Reserve (California, USA). For females (N = 24), we sampled the same seals before (late in molting fast) and after (early in breeding fast) their approximately seven month foraging trip. For males, we sampled different seals before (N = 14) and after (N = 15) their approximately four month foraging trip. We observed strong relationships among tissues for many, but not all compounds. Serum POP concentrations were strong predictors of inner blubber POP concentrations for both females and males, while serum was a more consistent predictor of outer blubber for males than females. The ability to estimate POP blubber concentrations from serum, or vice versa, has the potential to enhance toxicological assessment and physiological modeling. Furthermore, predictive equations may illuminate commonalities or distinctions in bioaccumulation across marine mammal species.

In this research, we examine the effects of PM10 and CO2 air pollutants on infant mortality and life expectancy at birth, in 60 developing countries during the period 1990–2010 by using unbalanced panel data and recursive simultaneous equations model. Our results show that the gains are obtained in the health status through the improvement in socio-economic conditions can be canceled by PM10 and CO2 air pollutants. Therefore, health policies which just focus on socio-economic aspects and ignore the adverse impacts of the air pollution may do little in efforts directed to improve the current health status of developing countries.

On January 31, 2014, an oil spill accident occurred in Yeosu, South Korea. A total 800–899kl of oil from the pipeline was spilled into the sea. After the oil spill, the KIOST (Korea Institute of Ocean Science & Technology) researched PAHs (polycyclic aromatic hydrocarbons) in various media, but sedimentary PAHs were not analyzed despite their longer persistency than in other media. Therefore, this study examined PAH levels in intertidal sediments around Gwangyang Bay and identified PAH sources using oil fingerprinting. PAH residual levels showed a dramatic decrease during the four months after the accident and then remained at a relatively constant level. Analysis through regression equations indicate that this study area is likely to be restored to the PAH levels prior to the accident. Furthermore, the source analysis and oil fingerprinting analysis showed that PAH contamination in this study was unlikely to have originated from the spilled oil.

A novel aerobic denitrification and biomineralization strain CN86 was isolated from the Qu Jiang artificial lake. Based on phylogenetic characteristics, the isolated strain was identified as Acinetobacter species. Strain CN86 was confirmed to have the ability to perform simultaneous denitrification and biomineralization. Exponential decay equation was used for the matching of kinetic processes on denitrification and biomineralization. A highest nitrate removal rate was achieved at the pH7.0, organic concentration of 1.5g/L and temperature of 30°C. An optimal hardness removal rate was obtained at the pH9.0, organic concentration of 2.0g/L and temperature of 30°C. Strain CN86 is a suitable candidate for the simultaneous removal of nitrate and hardness in groundwater treatment.

Nitrogen pollution in ground and surface water significantly affects the environment and its organisms, thereby leading to an increasingly serious environmental problem. Such pollution is difficult to degrade because of the lack of carbon sources. Therefore, an electrochemical and biological coupling process (EBCP) was developed with a composite catalytic biological carrier (CCBC) and applied in a pilot-scale cylindrical reactor to treat wastewater with a carbon-to-nitrogen (C/N) ratio of 2. The startup process, coupling principle, and dynamic feature of the EBCP were examined along with the effects of hydraulic retention time (HRT), dissolved oxygen (DO), and initial pH on nitrogen removal. A stable coupling system was obtained after 51 days when plenty of biofilms were cultivated on the CCBC without inoculation sludge. Autotrophic denitrification, with [Fe²⁺] and [H] produced by iron–carbon galvanic cells in CCBC as electron donors, was confirmed by equity calculation of CODCᵣ and nitrogen removal. Nitrogen removal efficiency was significantly influenced by HRT, DO, and initial pH with optimal values of 3.5 h, 3.5 ± 0.1 mg L⁻¹, and 7.5 ± 0.1, respectively. The ammonia, nitrate, and total nitrogen (TN) removal efficiencies of 90.1 to 95.3 %, 90.5 to 99.0 %, and 90.3 to 96.5 % were maintained with corresponding initial concentrations of 40 ± 2 mg L⁻¹ (NH₃–N load of 0.27 ± 0.01 kg NH₃–N m⁻³ d⁻¹), 20 ± 1 mg L⁻¹, and 60 ± 2 mg L⁻¹ (TN load of 0.41 ± 0.02 kg TN m⁻³ d⁻¹). Based on the Eckenfelder model, the kinetics equation of the nitrogen transformation along the reactor was N ₑ = N ₀ exp (−0.04368 h/L¹.⁸⁴³⁸). Hence, EBCP is a viable method for advanced low C/N ratio wastewater treatment.

Using ZnO nanoparticles, comparisons between sorption and sono-sorption efficiencies, equilibrium and kinetics in Direct Red 23 have been researched under the various experimental conditions. Pseudo-second-order model was practiced for the experimental data. The mechanism of the dye uptake was clarified based on the analyses of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Brunauer-Emmett-Teller (BET) surface area and total pore volume of the nanoparticles were obtained. The highest Direct Red 23 (DR23) removal efficiencies by sorption and sono-sorption processes were determined as 78.6 and 96.8 %, respectively. Experimental data have been evaluated according to Langmuir, Freundlich and Dubinin-Radushkevich. The mean energies of sorption and sono-sorption processes were calculated to be 16.22 and 25.41 kJ/mol, respectively. Arrhenius equation was used to calculate the activation energies. ΔH° and ΔG° values indicated that sorption and sono-sorption processes were endothermic processes. But, negative free energy values of ΔG° indicated that sorption and sono-sorption processes were favoured at high temperatures.

The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 (⁸⁸Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 (⁹⁰Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water containing known quantities of strontium. Based on the strontium content of that water, the plants were divided into five groups (treatments) and strontium content of the soil, and 30-day-old plants were determined by inductively coupled plasma atomic emission spectroscopy instrument (ICP-AES). Data on the strontium content of soil and plants enabled the development of a model using MATLAB, a mathematical software package, which included curve fitting and problem solving using regression equations and differential equations. Although strontium curves for leaves, stems, and roots of Chinese cabbage were not exactly the same, all showed a non-linear increase when compared with the increase in the content of strontium in soil. Strontium curves for leaves, stems, and roots of spinach were very similar and showed an initial increase followed by a decrease. Strontium concentrations in both Chinese cabbage and spinach were initially related to the concentrations of sodium and sulfur, the next two relevant nuclides being calcium and magnesium. The relationship between calcium and strontium in Chinese cabbage was different from that in spinach. By using ⁸⁸Sr to simulate the transfer of radionuclide ⁹⁰Sr from soil to a crop, the relevant data required to deal with accidental release of strontium can be obtained using a fitting curve and regression equations, thereby providing some experimental basis for evaluating the potential hazards posed by such accidents to the food chain.

Sorption equilibria of copper(II) ions onto palygorskite and sepiolite clay minerals were studied as a function of temperature. The experimental data were fitted to the Langmuir, Freundlich, Temkin, and R-D models to obtain the isothermal constants. van’t Hoff, Gibbs, Clausius–Clapeyron, and modified Arrhenius equations were also employed to evaluate the thermodynamic parameters involved in Cu sorption. The results showed that fibrous clay minerals exhibit enhanced Cu(II) sorption capacities at higher temperatures. Enthalpy changes (ΔH°) were found to be positive, confirming that the process of Cu(II) sorption on both palygorskite and sepiolite was endothermic. Positive values were also obtained for the entropy changes (ΔS°), which suggests increased randomness at the solid-solution interface during the sorption of Cu(II) ions on both fibrous clay minerals investigated. The free energy changes (ΔG°) were negative for all the different temperatures and initial Cu(II) concentrations tested, indicating that sorption on the minerals is spontaneous and favorable. It was, therefore, concluded that sorption of Cu(II) ions on fibrous clay minerals is entropically driven. The values of isosteric heat of sorption (∆H ₓ) decreased with increasing sorption density, which shows that the clay surface is heterogeneous in terms of the active sites available for Cu(II) retention. The values of activation energy (E ₐ) and sticking probability (S *) generally lied within the ranges associated with physisorption for palygorskite and chemisorptions for sepiolite. In conclusion, the thermodynamic parameters investigated revealed the higher tendency and capacity of sepiolite, compared to palygorskite, for the feasible, spontaneous, and endothermic retention of Cu(II). However, the intensity of Cu(II) interactions with the fibrous clay minerals was found to depend to a large extent on the temperature and the initial Cu loading of the systems.

The competitive/simultaneous adsorption of arsenite (As(III)) and arsenate (As(V)) onto ferrihydrite is one of main processes controlling the distribution of arsenic under oxidizing conditions in the natural environment. Adsorption reactions of As(III) and As(V) with ferrihydrite were investigated by employing a combination of batch adsorption experiments and Fourier transform infrared (FTIR) spectroscopy measurements in single and binary systems, i.e., both As species were present at the same time. Isotherm studies showed that the adsorption of As(III) in the binary system was less than that in single system, indicating that As(V) hindered As(III) adsorption. The presence of As(III) had almost no impact on As(V) adsorption at pH 5 in the binary systems. Freundlich model described the equilibrium data well (R ² > 0.94), and the adsorption affinity onto ferrihydrite was in the following order: As(III)-single > As(III)-binary > As(V)-single > As(V)-binary. Kinetic data of As(III) and As(V) from single and binary systems were both well described by pseudo-second-order equation (R ² > 0.98). FTIR showed that after adsorbing of either As species, a new peak occurred at 826 cm⁻¹ due to the formation of Fe-O-As bonds, indicating that competition between As(III) and As(V) could take place on the surface sites as a result of the formation of a similar surface complexes.

Adsorption of arsenic (III, V) from aqueous solution onto the synthesized α-Fe₂O₃/MCM-41 nanocomposite adsorbent, as function of contact time, initial concentration of the solution, temperature, pH, and presence of other anionic species, has been investigated. Characterization of adsorbent was performed via XRD, FT-IR, TGA, TEM, and N₂ adsorption–desorption techniques. The synthesized adsorbent belonged to the group of mesoporous materials with the mean pore diameter of 2.37 nm, specific surface area of 507.5 m² g⁻¹, and total pore volume of 0.571 cm³ g⁻¹. The experimental data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich (D–R) adsorption isotherms. Based on Langmuir isotherm, the maximum adsorption capacities at 298 K in the concentration range of 2–200 ppm were 133.3 and 102.1 mg g⁻¹ for As(ш) and As(v), respectively. The adsorption experiments at different contact times indicated that the kinetics of adsorption accurately followed the pseudo-second-order rate equation. Thermodynamics parameters were calculated, and it was found that the adsorption process was spontaneous, exothermic, and favored at lower temperatures. The capability of regeneration and reusability of adsorbent was also examined in alkaline solutions.