The effluents from bleached Kraft pulp mill (BKME) and paper industry are toxic to different aquatic organisms being an important source of contamination to aquatic environments due to the presence of several chemicals produced during the production of Kraft pulp. The main objective of the present study was to evaluate the exposure effects of a secondary-treated BKME in two different species of fish: Carassius auratus and Dicentrarchus labrax. Both species were exposed to different concentrations of secondary-treated effluent (1%, 10%, 25%, 50%, 100%) in semi-static tests under controlled laboratory conditions. At the end of the experimental period (21 days), samples of livers were collected for CYP1A determination and histopathological evaluation. The results show significant changes (p < 0.05) of CYP1A induction in carp exposed to 50% and in sea bass exposed to 25% of the effluent. Histopathological alterations were also observed according to the different concentrations of the tested effluent suggesting that tested BKME cause damage to exposed organisms.

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 Gorka pit lake was formed in an inactive Jurassic limestone quarry after cessation of open-pit dewatering. The main problem of the water quality in this area is linked to a large volume of extremely alkaline leachate disposed in the flooded quarry. The lake is meromictic due to a large density contrast between shallow and deep water layers. Water in the lake is of the Na-CO₃-OH type, pH is in the range from 11.5 to 13.3, and there are high concentrations of sulfate and several toxic elements (Al, As, Cr, Mo, P, and V). The chemical composition of the extremely alkaline leachate was formed as a result of the groundwater interaction with the industrial red mud wastes containing 5-10 wt.% of sodium carbonate. There is a trend of increasing concentrations and pH values with depth, mainly due to the in-gassing of atmospheric CO₂ into the surface layer and due to density stratification in the water column. Similar stratification is observed in groundwater wells around the lake. High dissolved concentrations of oxyanionic contaminants such as As, Cr, and V are caused by their high mobility and desorption under extremely alkaline conditions. In spite of reducing conditions at the bottom of the lake, caused by high concentrations of dumped organic matter, sulfate behaves conservatively because sulfate reducing bacteria do not survive in this pH range.

Photocatalytic degradation of bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA), a representative endocrine-disrupting compound, was carried out in the presence of the Ti-MCM-41 mesoporous molecular sieve in this investigation. The degradation rate was strongly dependent on those factors such as the catalyst, catalyst amount, radiation time, and pH value. The photolysis reaction was found to follow the Langmuir-Hinshelwood model. After the photocatalytic treatment, decomposition of BPA rendered five intermediates as follows: 2-methyl-2,3-dihydrobenzofuran, 4-hydroxyacetophenone, 1,1-diethoxyethane, isobutanol, and 3-methylbutanal, which could be the direct evidence supporting our proposal for the degradation mechanism.

The relationship between ambient concentrations of fine particulate matter and detrimental health effects remains a highly controversial issue. Increased incidence of mortality and morbidity due to cardiopulmonary complications has been associated with elevated levels of urban air particles with an aerodynamic of <2.5 μm (PM2.5). The main aim of this paper was to present the assessment of the temporal and spatial variations of the PM2.5 fraction and its contents in arsenic, cadmium, nickel and lead in order to identify possible emission sources of these pollutants. Daily ambient aerosol samples (PM2.5) were taken in the province of Castellón from 2008 to 2009. Particle concentration levels were determined by gravimetry, and the As, Cd, Ni and Pb levels in the samples were determined by inductively coupled plasma mass spectroscopy. The season variation of these pollutants differs according to the emission source and the factors involved in dispersion. In the weekly trend, there were no significant differences in levels among sampling sites in relation to the day activity (working vs. non-working) due to chemical pollutants that are found in fine particulate fractions residing in the atmosphere longer than coarse particles, resulting in a more homogeneous concentration of pollutants over time. In order to identify similar behaviour between chemical pollutants and PM2.5, an assessment of the correlation between them was carried out. This behaviour study shows whether the source of contaminants is the same. A statistical analysis of the levels of PM2.5 and the presence of As, Cd, Ni and Pb in the different sampling sites was performed in order to evaluate the influence of the sampling point on the concentrations of these pollutants.

In this study, the efficiency of chitin and chitosan toward the removal of ethylbenzene from aqueous solutions was investigated. Batch adsorption experiments of ethylbenzene-contaminated waters (5–200 mg/L) were carried out to evaluate the removal performance. Ethylbenzene uptake was determined from the changes in concentration, as the residual concentration was measured by gas chromatography with mass spectroscopy. The results indicated that the adsorption of ethylbenzene by chitin and chitosan were in agreement with the Langmuir isotherm, for two parameters model, and Redlich–Peterson isotherm, for three parameters model. A maximum removal percentage of 65% of ethylbenzene can be achieved using chitosan as adsorbent material. The adsorption capacity of ethylbenzene followed the order chitosan > chitin. The pseudo-second order rate model described best the adsorption kinetics of ethylbenzene for the two selected adsorbents. The kinetic studies also revealed that the pore diffusion is not the only rate controlling step in the removal of ethylbenzene. Overall, the study demonstrated that chitosan is a potential adsorbent for the removal of ethylbenzene at concentrations as high as 200 mg/L.

Over the past decades, the global production of petroleum coke, a by-product of the oil sand industry, has increased with the growing importance of oil sands as a source of fossil fuels. A greenhouse study using Triticum aestivum and Deschampsia caespitosa was conducted to assess the growth and physiological effects of coke on plants. The plants were grown in cokes with or without a cap of peat–mineral mix and were compared to plants grown in a peat–mineral mix (control). Our results indicate that the selected plants can survive in coke; however, stress symptoms such as reductions in transpiration (45–91%) and stomatal conductance rates (44–92%) in T. aestivum, biomass in T. aestivum (5–83%) and D. caespitosa (43–90%), photosynthetic pigments in T. aestivum (32–68%) and D. caespitosa (33–44%) and proline concentrations in D. caespitosa (77–97%) were observed. Furthermore, potentially phytotoxic concentrations of nickel (47–69 μg g−1 in D. caespitosa) and vanadium (9.3–18.3 μg g−1 in T. aestivum and 4–27.8 μg g−1 in D. caespitosa) were found in some tissues while molybdenum accumulated in D. caespitosa shoots at concentrations reported, in other studies, to cause molybdenosis in ruminants. These results suggest that the plants growing in coke could experience multiple stresses including water stress, nutrient deficiencies and/or Ni and V toxicity. Capping coke with peat–mineral mix limited the stress symptoms and could improve revegetation success of coke impoundment sites. This study provides baseline data for future long-term field studies essential for developing coke management guidelines.

The main goals of this study were (1) to standardize a simple and reliable embryotoxicity test for environmental contaminants and (2) to evaluate the presence and possible protective role of the multidrug resistance-associated (MRP) protein-mediated multixenobiotic defense in two Mediterranean sea urchin species, Paracentrotus lividus and Arbacia lixula. Toxic end-point used was the success of the first cell division in sea urchin embryos. Embryotoxicities of three environmentally relevant contaminants: mercuric chloride (HgCl2, 0.05–6 μM), trybutiltin (TBT, 2.5–500 nM), and oxybenzone (OXI, 0.1–100 μM); as well as seawater samples collected from the polluted and unpolluted locations, were determined and compared. A. lixula embryos were more sensitive to all three toxic compounds, and both P. lividus and A. lixula embryos were highly sensitive to TBT at nanomolar concentrations (EC50 49 ± 5 and 36.8 ± 3 nM, respectively). Inhibition of MRP protein by specific inhibitor MK571 caused significant increase in embryotoxic potency of HgCl2 (EC50 0.697 ± 0.03 and 0.245 ± 0.04 μM, respectively), TBT (EC50 24 ± 3 and 7.4 ± 1 nM, respectively) and polluted seawater sample, but not of OXI or unpolluted, natural seawater. Therefore, our results demonstrated for the first time the protective relevance of MRP proteins in early development of these two Mediterranean sea urchin species. Finally, the embryotoxicity protocol described in this study represents a simple and rapid bioassay for determination of environmentally relevant seawater contamination.

The efficiency of UV- and VUV-based processes (UV, VUV, UV/H2O2, and VUV/H2O2) for removal of sulfamethoxazole (SMX) in Milli-Q water and sewage treatment plant (STP) effluent was investigated at 20°C. The investigated factors included initial pH, variety of inorganic anions (NO3 − and HCO3 −), and humic acid (HA). The results showed that the degradation of SMX in Milli-Q water at both two pH (5.5 and 7.0) followed the order of VUV/H2O2 > VUV > UV/H2O2 > UV. All the experimental data well fitted the pseudo-first order kinetic model and the rate constant (k) and half-life time (t 1/2) were determined accordingly. Indirect oxidation of SMX by generated .OH was the main degradation mechanism in UV/H2O2 and VUV/H2O2, while direct photolysis predominated in UV processes. The quenching tests showed that some other reactive species along with .OH radicals were responsible to the SMX degradation under VUV process. The addition of 20 mg L−1 HA significantly inhibited SMX degradation, whereas, the inhibitive effects of NO3 − and HCO3 − (0.1 mol L−1) were observed as well in all processes except in UV irradiation for NO3 −. The removal rate decreased 1.7–3.6 times when applying these processes to STP effluent due to the complex constituents, suggesting that from the application point of view the constituents of these complexes in real STP effluent should be considered carefully prior to the use of UV-based processes for SMX degradation.

Pharmacologically active substances used in the treatment of human and animal illnesses may usually enter the aquatic environment via effluents from sewage treatment plants, as they are not completely biodegraded or removed during waste water treatment. 17β-Estradiol genotoxicity was evaluated in Oreochromis niloticus (family Cichlidae) using micronucleus test, other nuclear abnormalities assessment, and the comet assay with erythrocytes. Fish were exposed to aqueous systems contaminated with 6 ng/L 17β-estradiol for three periods: 24 h, 48 h, and 10 days. The results showed that 17β-estradiol has genotoxic potential in different periods, since significant differences (P = 0.036) were observed in the micronucleus frequencies of the 10-day exposure groups in relation to the control group. Also, the same was observed when comparing the nuclear abnormality frequencies (P = 0.018) of the 24-h exposure group with the negative control group, and when using comet assay (P < 0.001) for 48-h evaluations. The tested concentration of the 17β-estradiol gave rise to mutagenic and genotoxic effects on the blood cells of O. niloticus, therefore the substance being considered a clastogenic chemical contaminant on both acute and chronic exposures. The assessment using a combination of micronucleus test, nuclear abnormalities, and comet assays proved to be suitable and useful in the genotoxicity testing of 17β-estradiol at nanograms per liter.