Soils and different vegetable species in Costa de Caparica (Portugal) are subject to the intensive use of inorganic fertilizers and pesticides. Thus, the concentrations of As, Cu, Fe, Mn, Pb, and Zn were evaluated. Lettuce, spinach, and potatoes collected in station 9 cause reason for concern due to their high Pb concentrations close to 20 μg g⁻¹ which is probably related to an intensive use of copper and iron sulphate fertilizers. Additionally, the consumption of Portulaca oleracea collected in stations 3 and 4 must be avoided due to the high concentrations of Zn, and even Cu. The derived estimated daily intake (EDI) dose of Zn will be a risk to human consumption if P. oleracea was the single basis of a soup, although the addition of other ingredients might lower the tolerable upper intake (TUI) value of 39 mg/day of P. oleracea, to admissible levels, i.e., not exceeding 25 mg/day. Pumpkin collected in station 1 contained 44.1 μg g⁻¹ Cu and a TUI value of 9.8 mg/day, when the recommendation must not exceed 5.0 mg/day. In this context, it is strongly advised to not include this vegetable in household menus.

One of the most common compounds in pesticide formulations, plastics, and papers is 4-nonylphenol (4-NP). It is contained in agricultural, industrial, and wastewater effluents, which when discharged into surface waters affect aquatic fauna. Therefore, the present study aimed to use Biomphalaria alexandrina snails to evaluate the chronic toxicity of 4-NP. Its concentrations in collected water samples from Giza Governorate ranged from 400 to 1600 μg/l. Based on these environmentally relevant concentrations, laboratory experiments were carried out using standard 4-NP to investigate the effect of three concentrations; namely 400, 750, and 1600 μg/l. Survival rate of the exposed snails to 4-NP concentrations was affected after 4 weeks. Reproduction of the exposed snails to 4-NP concentrations was lower than that of the control at 30 °C, while the exposed snails to 400 μg/l of 4-NP showed maximum reproduction at 15 °C. The lowest hatchability percentage was recorded with egg masses laid by the exposed snails to 400 and 1600 μg/l of 4-NP at 15 and 30 °C, respectively. Furthermore, the results showed fluctuated levels of progesterone, estradiol, and testosterone depending upon the concentration and the temperature, which played a key role in determining the degree of 4-NP toxicity.

Intensive anthropogenic activities may add to pollution risks to lakes and rivers, which can be revealed by the magnetic characteristics of sediments. The present study aims to assess the pollution status of the sediment of a typical reservoir in northwestern China by application of magnetic susceptibility. The values of magnetic susceptibility exhibited significant positive correlations with trace metals (Co, Cu, Mn, Ni, and V) and natural radionuclides (²³²Th and ⁴⁰K). Multivariate statistical analysis indicated common sources and similar deposition characteristics of magnetic particles and trace metals. It was conformed that magnetic susceptibility could be used as an indicator to identify industrial sources of trace metals, but was not suitable to indicate the traffic or natural sources. Linear regression equations between the low-frequency magnetic susceptibility and the integrated pollution index as well as annual effective dose rate indicated a potential for using magnetic susceptibility in semi-quantitative assessment of trace metal pollution and radiological hazard in sediments. A three-step procedure is proposed for the use of magnetic susceptibility in pollution monitoring, which provides a fast and effective method for estimating the pollution extent and tracing the major sources of trace metals in the sediment of lakes and rivers.

To conduct a comprehensive ecological analysis on the solid residues derived from the thermal disposal of hyperaccumulator Pteris vittata, this study focused on the behaviors of As and Pb and the characteristics of environmentally persistent free radicals (EPFRs) in the solid residues under different thermal treatment conditions. The analysis results revealed that the concentrations of As in the biochars and bio-slag were approximately 350 and 1100 mg/kg, respectively. Moreover, the concentrations of Pb in the solid residues varied from 34 to 1050 mg/kg. According to the results of the modified BCR sequential extractions, As is more stable in the biochar while Pb is more stable in the combustion slags. In addition, As showed a higher volatilization temperature compared with Pb. The ecological risk assessment indicated that the correlation index between the contamination factor (Cf) of As and the risk index (R² = 0.995) is considerably larger than the correlation index between the contamination factor of Pb and the risk index (R² = 0.117), which implies that the pyrolysis method should be selected at priority. Moreover, the EPFR concentrations of the biochar declined by approximately 75 times when the pyrolysis temperature increased from 500 to 600 °C. This behavior indicated that high-temperature pyrolysis (> 600 °C) could simultaneously control both the heavy metal behavior and EPFR concentrations.

An unsafe level of manganese (Mn) was detected in the drinking water in some arsenic (As)-contaminated areas in Bangladesh. Mn is an essential trace element; however, the intake of a higher level of Mn through the drinking water is associated with the development of toxicity in humans. This study was designed to evaluate the effects of As and Mn co-exposure on neurobehavioral and biochemical alterations in a mouse model. Sodium arsenite (10 mg/kg body weight) and manganese chloride tetrahydrate (10 mg/kg body weight) were given to mice individually and in combination with drinking water for 90 days. Results showed that individual As and Mn exposure as well as co-exposure of As and Mn significantly (p < 0.05) reduced the percent of time spent in the open arms when compared with that of control mice. In addition, percent of time spent in open arms significantly (p < 0.05) increased in co-exposed mice compared with As exposure in elevated plus maze (42.05 ± 1.10 versus 38.94 ± 0.66). In the Morris water maze test, the mean time latency to find the platform was longer in metal-treated mice in comparison to that of control mice (p < 0.05). Importantly, the co-exposed group had shorter time when compared with the As-exposed group during the training periods (p < 0.05). Moreover, co-exposed mice stayed significantly (p < 0.05) more time in the target quadrant in the probe trial in comparison with that of As-exposed mice (27.25 ± 1.21 versus 23.83 ± 0.87 s) but less time than control mice (27.25 ± 1.21 versus 43.17 ± 1.49 s). In addition, a significant (p < 0.05) alteration of biochemical parameters such as ALT, AST, ALP, BChE, and SOD as well as urea and creatinine levels were noted in the As-exposed group compared with the control group and Mn significantly (p < 0.05) attenuated the effects of As in co-exposed mice. Therefore, the results of this study suggest that As and Mn may have some antagonistic effect and Mn could attenuate the As-induced neurobehavioral and biochemical alterations in co-exposed mice.

Today, environmental pollution, especially heavy metal pollution, is known as a new and possibly more dangerous pollutant than other environmental ones. For this purpose, the uptake of four aquatic plants in different environments was chosen. In this experiment, four macrophytes, i.e., umbrella palm (Cyperus alternifolius), duckweed (Lemna minor), water hyacinth (Eichhornia crassipes), and canna (Canna × generalis), were studied in five contaminated aquatic environments, i.e., Gohar Rood river, Zarjoob river, Eynak lagoon, Anzali lagoon, and control solution (containing Cd, Cr, Pb, and Zn). The results showed that the highest uptake rates of cadmium, cobalt, vanadium, chromium, zinc, nickel, and lead were observed for duckweed fronds. The highest bioconcentration factor (BCF) of nickel was related to duckweed stem and water hyacinth root, and the highest BCF of cadmium belonged to duckweed fronds and canna root. The highest rate of uptake of cadmium, chromium, zinc, and lead was related to control. The least amount of uptake of several metals by plants was obtained from the water of Gohar Rood and Zarjoob. Generally, based on the results of this study, it can be stated that duckweed is suitable for the uptake of most heavy metals.

This study mainly focuses on the preparation, characterization, and sorption performance for Cu(II) and Zn(II) by using nano-alumina material (NA) synthesized through the sol-gel method. The SEM, EDS, FT-IR, and XRD analysis methods were implemented to identify the micromorphology and crystal structure of the synthesized NA absorbent and its structure after the adsorbing procedure. The effect of effective variables including various absorbent dose, contact time, initial ion concentration, and temperature on the removal of Cu(II) and Zn(II) from aqueous solution by using NA was investigated through a single factor experiment. Kinetic studies indicated that adsorption of copper and zinc ions by NA was chemical adsorption. The adsorption isotherm data were fitted by Langmuir (R²: 0.919, 0.914), Freundlich (R²: 0.983, 0.993), and Temkin (R²: 0.876, 0.863) isotherms, indicating that copper and zinc ions were easily adsorbed by NA with maximum adsorption capacities of 87.7 and 77.5 mg/g for Cu²⁺ and Zn²⁺, respectively. Thermodynamic parameters indicated that the adsorption of Cu²⁺ was spontaneous(G<0) and the adsorption of Zn²⁺ might not be spontaneous (G > 0) by NA. Graphical abstract ᅟ

Poly(L-lactic acid) (PLLA) can be used as an external electron donor in denitrification reactors to treat drinking water, aquaculture water, and industrial wastewater with an imbalanced carbon/nitrogen ratio. However, for PLLA to function in these applications, its chemical hydrolyzability requires improvement. Although the adjustment of the crystallinity (Xc) is effective in improving the hydrolyzability of PLLA, the condition for the Xc of PLLA, in which a sufficient amount of lactic acid is released for denitrification, must be clarified. Therefore, this study investigated the effective Xc range and optimal PLLA content as an electron donor for continuous nitrate removal in denitrification reactors. This study also explored the abundance, succession, and diversity of active denitrifying bacteria in denitrification reactors. The nitrate removal activity of activated sludge using the highly crystalline PLLA (Xc = 39.4%) was 1.8 mg NO₃⁻ -N g MLSS⁻¹ h⁻¹, which is 2.4 times higher than that using the nearly amorphous PLLA (Xc = 0.9%). During the 57 days of operation, the denitrification reactor with 3% (w/v) highly crystalline PLLA continued to completely remove nitrate, with a maximum nitrate removal activity of 22.8 mg NO₃⁻ -N g MLSS⁻¹ h⁻¹. The 16S rRNA amplicon sequencing and clone library analyses are using transcripts of two nitrite reductase genes, encoding cytochrome cd₁ nitrite reductase, and copper-containing nitrite reductase revealed that bacteria belonging to the families Comamonadaceae, Rhodocyclaceae, and Alcaligenaceae were active denitrifying bacteria in the denitrification reactor using PLLA.

Based on the compartment and exponential models, the distribution of Fukushima-derived ¹³⁷Cs was evaluated at four sampling dates in undisturbed coniferous forest soil. The compartment model was employed to evaluate the dynamic of ¹³⁷Cs in the three sub-sections of the forest floor (FF), namely undergrowth (UG), litter layer (OL), and fragmented litter layer (OF), while the exponential model was administrated to describe its distribution below the FF. According to the compartment model, the derived ecological half-life of ¹³⁷Cs in the UG, OL, and OF layers was 0.97, 1.1, and 4.9 years, respectively, indicating ¹³⁷Cs resides much longer in the OF layer. Hence, this soil section remains a potential source of radiation dose mainly due to its high ¹³⁷Cs content associated with low attenuation effect. Below the OF layer, the ¹³⁷Cs distribution was well described by exponential model and its derived relaxation lengths were in the range of 0.8–1.4 cm, implying the migration of ¹³⁷Cs in mineral soil is very slow and almost intact during the observation time. Collectively, our results highlighted that the compartment model for the FF and the exponential model for the soil below the FF are adequate enough to generate essential information. Thus, the potential decontamination measures should have to be chosen on their effect on the FF’s ¹³⁷Cs. Graphical abstract

The novel nano-flocculants were synthesized through a conjugation of dodecylamine with partly oxidized sodium alginate. The structures of the flocculants were characterized by FTIR, ¹HNMR, TGA, and EA. The flocculants possessed amphiphilic structures and formed nano-micelles through self-assembly in water. The nano-micelles showed rod-like shapes about 100 nm. Removal rates of the flocculants for Pb²⁺ and bisphenol A were determined under different conditions, showing the removal rates as high as 97.20% and 88.66% for Pb²⁺ and bisphenol A, respectively. The flocculation mechanisms were revealed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM), respectively. Isotherm adsorption studies indicated that the flocculation for Pb²⁺ accorded with the Langmuir single-layer adsorption model, and for bisphenol A accorded with the Freundlich multi-layer adsorption model. The quasi-second-order kinetic model was suitable for describing the adsorption kinetics. The new nano-flocculant was a promising agent for removing both heavy metal ions and organic pollutants of wastewater.