It is suspected that drinking water containing fluoride and aluminum results in negative health effects especially on brain, liver, and kidney. In this investigation, the effect of F, Al, and AlFₓ complex on chronic kidney disease (CKD) was investigated. Mice were treated either with WHO recommended or slightly higher F and Al levels in drinking water. Treatment solutions contained 0.05–10.0 mg/L of F, 0.08–10.0 mg/L of Al, or 0.07–15 mg/L of AlFₓ, and the treatment period was 42 weeks. Blood urea level and creatinine levels were investigated as a measure of malfunction of kidneys. Histopathological evaluations of kidney tissues were carried out to assess the extent of damage that F, Al, and AlFₓ complex could cause. It was demonstrated that the treated drinking water containing F and Al with par with WHO or moderately above the WHO levels or AlFₓ in low level (0.07–15 mg/L) does not lead to CKD in mice.

Over the last several decades, ionic liquids have become a promising alternative to conventional organic solvents. Initially, ionic liquids were described as “environmentally friendly” substances. However, the results of numerous studies proved that the effects of these compounds on individual ecosystems might be adverse. The presented paper discusses the effect of ionic salts containing natural chiral substituent: (1R,2S,5R)-(−)-menthol in cation and a tetrafluoroborate anion of a general formula of [Cₙ-Im-Men][BF₄] of implementation into the soil on the growth of spring barley and common radish in their early development stages. The obtained results showed that the greatest phytotoxicity was exhibited by ionic liquids containing substituents with the smallest possible number of carbon atoms. The further increase in the length of the chain did not increase the toxicity of these salts for terrestrial plants. Moreover, a compound with a substituent having a chain length of 11 carbon atoms was found to be non-toxic to common radish. The experiment under discussion showed also the effect of these tetrafluoroborates, used in the form of spray, on the development of common sorrel, gallant soldier and white goosefoot. The tests carried out also showed that the most toxic were the compounds with 1 and 3 carbon atoms. The phytotoxicity of tetrafluoroborates was positively correlated with the concentration of these compounds in the soil and was dependent on the genetic features of the genres and varieties of plants used in the experiment.

Marine protected areas (MPAs) are vulnerable to many pressures, including pollution. However, environmental quality monitoring in these areas traditionally relies on only water chemistry and microbiological parameters. The goal of the current study was to investigate the role of a set of biomarkers in different target organs (liver, kidney, and gills) of fish in order to assess the environmental quality of an MPA (MTs, GPx, GST, GSH, DNA damage, LPO, AChE, and condition index). Chemical analyses were also performed on liver and muscle tissues to evaluate metal body burdens, and PAHs were identified in bile. A demersal fish (Cathorops spixii) that is widely consumed by the local population was used as bioindicator species, and the results were integrated using multivariate analysis. The use of the biomarker approach allowed for the identification of both seasonal and spatial variations in pollution sources around the Environmental Protected Area of Cananéia-Iguape-Peruíbe (APA-CIP). Higher metal body burdens associated with biological responses were found in the sites under the influence of urban areas during the dry season, and they were found in the sites under the influence of the Ribeira de Iguape River (RIR) during the rainy season. The liver was found to be more responsive in terms of its antioxidant responses, whereas gills were found to be more responsive to biomarkers of effect. These results show that this set of biomarker analyses in different organs of fish is a useful tool for assessing chemical pollution in an MPA.

Wind-induced sediment suspension and nutrient release is an important source for shallow eutrophic lakes. This work studies the quantitative relationship between wind speed and sediment release rate in Meiliang Bay of Lake Taihu, China, using field observations and indoor simulations. Natural wind, water flow, and water quality conditions were synchronously monitored to establish the relationship between wind speed and sediment release rate. Sediment suspension processes under different wind speeds were also simulated in a specially designed reactor. We then established the relationship between natural wind speed and indoor-simulated sediment release rate through hydrodynamic conditions (expressed using water shear stress). The indoor experiment was a supplement to the field observations. The results showed that (1) the critical wind speeds at which sediment became suspended and demonstrated maximum suspension were approximately 3–4 and 8 m s⁻¹, respectively; (2) the relationship between wind speed and suspended sediment (SS), total nitrogen (TN), and total phosphorous (TP) release rate could be expressed by exponential functions (SS release rate: y = 1.287e⁰.¹⁷⁷ˣ , R ² = 0.981; TN release rate: y = 37.55e⁰.³⁶³ˣ , R ² = 0.981; TP release rate: y = 0.381e⁰.¹⁸⁶ˣ , R ² = 0.945); and (3) the critical (wind speed, 8 m s⁻¹) release rates of SS, TN, and TP were 1000, 5.8, and 2.2 g m⁻² day⁻¹, while the maximum (wind speed, 16 m s⁻¹) rates were 5000, 24.7, and 5.4 g m⁻² day⁻¹, respectively.

Low-cost and environmentally friendly mediators could facilitate the application of laccase (EC 1.10.3.2) in variant biotechnological processes. Acetylacetone (AA) represents an inexpensive and low toxic small molecular diketone that has been proven as an effective mediator for laccase in free radical polymerization. However, the potential of AA as a mediator for laccase in pollutant detoxification and/or degradation is still unknown. In this work, the roles of AA in laccase-induced polymerization and transformation were investigated. AA was demonstrated to be a highly efficient mediator in the laccase-induced grafting copolymerization of acrylamide and chitosan. The efficacy of AA in the laccase-induced decoloration of malachite green (MG) was compared with that of the widely used 1-hydroxybenzotriazole (HBT). The laccase-AA system had the highest turnover number (TON, 39.1 μmol/U), followed by the laccase-only system (28.5 μmol/U), while the TON of the laccase-HBT system was the lowest (14.9 μmol/U). The pseudo-first-order transformation rate constant (k ₁) of MG in the laccase-AA system was up to 0.283 h⁻¹ under the given conditions, while the k ₁ of AA caused by laccase was only 0.008 h⁻¹. In the five-cycle run, the concentration of AA remained stable. The larger TON of the laccase-AA system and the stability of AA in the cycling runs demonstrate that AA was more recyclable than HBT in the LMS, leading to a prolonged serving life of laccase. These results suggest that AA might be a potential redox mediator for laccase.

Biofouling material samples from the Arabian (Persian) Gulf, used as inocula in batch cultures, brought about crude oil and pure-hydrocarbon removal in a mineral medium. Without any added nitrogen fertilizers, the hydrocarbon-removal values were between about 10 and 50 %. Fertilization with NaNO₃alone or together with a mixture of the vitamins thiamine, pyridoxine, vitamin B12, biotin, riboflavin, and folic acid increased the hydrocarbon-removal values, to reach 90 %. Biofouling material samples harbored total bacteria in the magnitude of 10⁷cells g⁻¹, about 25 % of which were hydrocarbonoclastic. These numbers were enhanced by NaNO₃and vitamin amendment. The culture-independent analysis of the total bacterioflora revealed the predominance of the gammaproteobacterial genera Marinobacter, Acinetobacter, and Alcanivorax, the Flavobacteriia, Flavobacterium, Gaetbulibacter, and Owenweeksia, and the Alphaproteobacteria Tistrella, Zavarzinia, and others. Most of those bacteria are hydrocarbonoclastic. Culture-dependent analysis of hydrocarbonoclastic bacteria revealed that Marinobacter hydrocarbonoclasticus, Dietzia maris, and Gordonia bronchialis predominated in the fouling materials. In addition, each material had several more-specific hydrocarbonoclastic species, whose frequencies were enhanced by NaNO₃and vitamin fertilization. The same samples of fouling materials were used in four successive crude-oil-removal cycles without any dramatic loss of their hydrocarbon-removal potential nor of their associated hydrocarbonoclastic bacteria. In the fifth cycle, the oil-removal value was reduced by about 50 % in only one of the studied samples. This highlights how firmly biofouling materials were immobilizing the hydrocarbonoclastic bacteria.

In vivo and in vitro exposures were used to investigate the genotoxicity of mercuric chloride (HgCl₂) to the marine snail, Planaxis sulcatus. The comet assay protocol was validated on gill cells exposed in vitro to hydrogen peroxide (H₂O₂, 0–50 μM). Snails were exposed in vivo for 96 h to HgCl₂ (10, 20, 50, and 100 μg/l). Our results showed significant concentration-dependent increase in the tail DNA (TDNA) and olive tail moment (OTM) in exposed snails for all doses compared with controls. In vitro exposure to HgCl₂ (10–100 μg/l) resulted in significantly higher values for TDNA at all concentrations. Our results showed that DNA damage increased in the gill cell with increasing exposure time. This study demonstrates the usefulness of comet assay for detection of DNA damage after exposure to HgCl₂ and the sensitivity of marine snail P. sulcatus as a good candidate species for metal pollution.

Discharge of dye-containing wastewater by the textile industry can adversely affect aquatic ecosystems and human health. Bioremoval is an alternative to industrial processes for detoxifying water contaminated with dyes. In this work, active and inactive biomass of the microalga Chlorella vulgaris was assayed for the ability to remove Congo Red (CR) dye from aqueous solutions. Through biosorption and biodegradation processes, Chlorella vulgaris was able to remove 83 and 58 % of dye at concentrations of 5 and 25 mg L⁻¹, respectively. The maximum adsorption capacity at equilibrium was 200 mg g⁻¹. The Langmuir model best described the experimental equilibrium data. The acute toxicity test (48 h) with two species of cladocerans indicated that the toxicity of the dye in the effluent was significantly decreased compared to the initial concentrations in the influent. Daphnia magna was the species less sensitive to dye (EC₅₀ = 17.0 mg L⁻¹), followed by Ceriodaphnia dubia (EC₅₀ = 3.32 mg L⁻¹). These results show that Chlorella vulgaris significantly reduced the dye concentration and toxicity. Therefore, this method may be a viable option for the treatment of this type of effluent.

The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC) × GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solid-phase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84–98.49 %, 80.75–97.11 %, and 78.27–97.08 % for BPA, o-NTP, and PCP, respectively) . The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.

The influence of Chlorella sorokiniana on drinking water’s biological denitrification was studied at two different initial nitrate concentrations, 50 and 100 mg/L, respectively. Sucrose and grape juice were used as carbon sources. The experiments showed that the denitrification process in the presence of algae was, even at low concentrations, i.e. 50 mg/L of nitrate, slower than without them, but yet still more than 95 % of nitrate was removed in 24 h. It was also discovered that, with the addition of ammonium and urea, the urea interfered much more with the denitrification process, as less than 50 % of the initial nitrate was removed. However, algae did not contribute to the nitrate and ammonium removals, as the final concentrations of both in the presence of algae were higher by approx 5 %. At 100 mg/L of initial nitrate, the denitrification kinetics in the presence of algae was apparently slower regarding those experiments at lower levels of nitrate and only 65–70 % of nitrate was removed over 24 h. Using grape juice instead of sucrose improved the nitrate removal slightly.