High concentration of fluorine (F) in agricultural soils has got significant attention considering its impacts on human health, but little information was available about F distribution in farmland soil profiles around phosphorous chemical industry factories. In present study, farmland soil profiles and relevant medium samples were collected from farmlands around a main phosphorous chemical base in southwest China. At 0–100-cm profiles, concentrations of soil total F (Ft, 400.9–1612.0 mg kg⁻¹) and water soluble F (Fw, 3.4–26.0 mg kg⁻¹) decreased with profile depth in industrial areas. Industrial activities enhanced F concentration in soil mainly at 0–40-cm profiles. No disparity for both Ft and Fw distributions in paddy-dry land rotation field and dry land indicates short-term land utilization could not affect the F distribution in soil profiles. Correlation analysis showed soil organic matter and wind direction were important factors influencing the distribution of F in soil profiles. The shutdown of factory and government control of industrial emissions effectively decreased the ambient air F (Fa) concentrations in industrial areas. In where Fa and dustfall F concentrations were high, high soil Ft, Fw, and crop edible part F concentrations were found.

Salts used in road de-icing during winter season inhibit the growth and development of lawn grass species. The mechanism of plant tolerance/sensitivity to such treatments is still not clear. Moreover, there is a lack of fast and non-invasive tool to detect the effect of these salts on plants growth. This study was designed to understand the tolerance mechanism of Kentucky bluegrass plants on salinity, based on some biometric and physiological parameters. In this experiment, we simulated the urban conditions where salts are used intensively for roads de-icing. Germination capacity was evaluated at five salt solutions of NaCl (0, 50, 100, 150 and 200 mM), and physiological parameters were measured during the tillering phase at salinity levels of 0, 150 and 300 mM of NaCl. Seeds of Kentucky bluegrass did not germinate under salinity. During tillering phase, salinity affected length, area and dry mass of roots as well as the relative water content of plants, negatively. Moreover, it influenced the maximum chlorophyll fluorescence yield, quantum yield of photosystem II and electron transport rate at early period of stress. This allows us to recommend these parameters for early detection of soil salinity effects on Kentucky bluegrass plants. It seems to be that the tolerance of this plant towards salinity is based on retaining water content in leaves that allow more efficient functioning of photosynthetic apparatus.

Highly porous biochar (BC) structures have been prepared from inexpensive biomasses like rice straw, bamboo, sugarcane waste, and corn cob via a slow pyrolysis technique in nitrogenous atmosphere. A surface engineering technique has been applied to enhance the surface-to-volume ratio of each biochar sample and finally compared its characteristics through standard surface and elemental characterization techniques, viz. CHN (carbon, hydrogen, and nitrogen), FTIR (Fourier transform infrared spectroscopy), BET (Brunauer–Emmett–Teller), and SEM (scanning electron microscopy). All the biochar samples were observed to be highly carbonized and aromatized. Exfoliated structures were found to contain more elemental carbon (34.14–77.32%) than its native form (30.92–74.46%). Aromatic hydrocarbon, aromatic C=C, aromatics, aliphatic C–O, aliphatic hydrocarbon, and H-bonded OH groups were found to predominate in the surface of biochar structures independent of their precursor composition and extent of exfoliation. SEM micrographic images clearly ensured about the unoriented sheets like the morphology of different biochar samples. Although no significant structural difference was found to exist depending on their precursor compositions, quantitative enhancement of porosity was found to be observed after exfoliation. Both native (240.65 m²/g) and exfoliated (712.89 m²/g) biochars derived from sugarcane wastes were observed to have a maximum surface area in comparison to the biochars derived from rice straw (native, 22.08 m²/g; exfoliated, 29.92 m²/g), bamboo (native, 42.08 m²/g; exfoliated, 248.38 m²/g), and corn cob (native, 136.62 m²/g; exfoliated, 221.71 m²/g). Exfoliated biochars were found to be consistently more potent in comparison to its native form as per our comparative characterizations performed so far.

The pyroligneous liquor is a product obtained during the production of charcoal, with well-known antimicrobial activity. In this work, we characterized the physical chemistry properties of a formulation composed of distilled pyroligneous liquor (DPL), obtained from Eucalyptus grandis, and chitosan. A good interaction between the polymer and the solvent was observed. Auto-supported films were prepared with these systems and characterized with respect to their structure and photo-protection properties, water vapor permeability, and resistance to water and to thermal degradation. They present a semi-crystalline structure and are hygroscopic, but are stable under immersion for up to 7 days. The swelling degree in water is 300% in weight and the permeability to water vapor was between 30 and 45 g m⁻¹ h⁻¹ (for films with 80 to 10 μm, respectively). The obtained films are able to efficiently block the incident UVB and UVC radiation; the molar absorptivity decreases exponentially with increasing wavelength and is stable up to 300 °C. These properties confer desirable properties to the films, obtained from these precursors of a renewable source, to be used as coatings.

Polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyl (dl-PCB) are groups of toxic compounds released into the environment as unintentional by-products of combustion. They persist, bioaccumulate through the food chain, and cause adverse health effects. This review attempts to collate available information on the release of PCDD/Fs and dl-PCBs and other critical data relevant to their monitoring in Africa during the existence of the Stockholm Convention (SC). Much as the implementation of the SC may be lagging, literature showed that there has been encouraging efforts that have been made with respect to PCDDs/Fs and dl-PCBs monitoring in Africa. Results from a global monitoring study showed that PCDD/Fs released to air in Africa stood at 18–532 fg WHO₉₈ TEQ/M³ while dl-PCBs were 7–278 fg WHO₉₈ TEQ/m³. In human milk, the total concentration of PCDD/Fs, i.e., WHO 2005 TEQ LB has been reported to range from 0.5 ng/g fat to 12 ng/g fat. Fourteen laboratories in Africa participated in inter-laboratory assessments of persistent organic pollutants (POPs) with two specifically for PCDD/Fs analysis. This shows that some efforts are being made to boost capacity in Africa. Levels of PCDDs/Fs and dl-PCBs in clay consumed by pregnant women have been reported in Cameroon, Democratic Republic of Congo (DRC), Nigeria, Zimbabwe, Ĉote d’Ivoire, and Uganda with a maximum concentration of 103 pg TEQ/g. This finding was very significant since women are the most impacted through exposure to POPs, a fact that is acknowledged by the SC.

Simulation and prediction of the pollution transport is one of the major problems in environmental and rivers engineering studies. The numerical tools have been used in simulation of the concentration profile transmission for description of river water quality. The one-dimensional advection-dispersion equation (ADE) is used in applied water quality modeling and requires the accurate estimation of longitudinal dispersion coefficient (Dₓ). This paper develops a hybrid numerical-intelligence model for dispersion modeling in open-channel flows. The main contribution of this paper is to improve the results of 1D numerical simulation of pollutant transport in steady flows by estimation of dispersion coefficient (Dₓ) based on artificial intelligence models and subset selection of maximum dissimilarity (SSMD). The developed hybrid model uses an intelligence module based on optimized adaptive neuro fuzzy inference system (ANFIS) and artificial neural networks (ANNs) for longitudinal dispersion estimation, in which their structures are optimized by genetic algorithm (GA). Intelligence estimates of Dₓ by ANN, ANFIS, ANFIS-GA, ANN-GA, multiple linear regression (MLR), and empirical equation are compared with observed values of Dₓ available in 505 river section, and the ANFIS-GA, as the most accurate, is incorporated and integrated with developed 1D-ADE numerical module. The numerical solution of 1D-ADE is done using physically influenced scheme (PIS) for face flux estimation in finite volume method. The performance of hybrid models PIS-ANFIS-GA, PIS-ANFIS, and PIS-empirical is compared using the R², RMSE, MAE, and NSE values in comparison with analytical solution and measured concentration hydrographs. The results revealed that the hybrid numerical-intelligence model is more accurate than the other classical methods for sediment/pollutant dispersion prediction in open-channel flows. The developed hybrid numerical-intelligence model can accurately simulate the dispersion processes in rivers and is a novel step in applicability of ANFIS-GA and ANN-GA models. Graphical abstract ᅟ

Moss and lichen bag technique (Dicranum sp., Hypnum sp., Polytrichum sp., Hypogymnia physodes) and activity of soil enzymes (urease, acid and alkaline phosphatase, fluorescein diacetate, ß-glucosidase) were used as bioindicators of air and soil pollution in Dubník former mining area (East Slovakia). Ten open mining pits and 8 heaps of waste material were chosen for the research purposes. Contamination factor (Cf), degree of contamination (Cd), and pollution load index (PLI) were used to evaluate the level of soil pollution and relative accumulation factor (RAF) expressed the level of air pollution by risk elements (As, Cd, Cu, Fe, Mn, Ni, Sb, Pb, Zn). Based the degree of contamination results, the study area was polluted by individual elements in the following order: Fe>Cd>As>Pb>Sb>Zn>Cu>Ni>Mn. The highest values of Mn and Ni and lower values of urease were determined in open mining pits comparing heaps of waste material. The results of PLI index confirmed extreme pollution at all sampling sites. Considering the average RAF values showed the decrease of accumulation abilities of evaluated taxa in the following order: Dicranum sp.>Hypnum sp.>Hypogymnia physodes>Polytrichum sp.

The surface soils were collected from four areas in the Yellow River Delta (YRD), including three functional areas in the natural reserve of the YRD (the core area, buffer area, and experimental area) and a neighboring area of the natural reserve. The total concentrations, speciations, contamination status, and health risk assessments of the mercury (Hg) and arsenic (As) in surface soils of the YRD were investigated. The average Hg concentration was about three times that of the background value, while As was just slightly higher than the background. Hg levels in the sites of experimental area were significantly higher than those in the core area and buffer area, which was consistent with the human activity intensities of the three functional areas. However, no significant differences of As levels were observed across different areas. According to the sequential extraction experiments, only less than 5% of Hg and As were associated with the exchangeable fraction, while over 80% of them were found in the residual fraction, indicating low mobility and bioavailability of both Hg and As. The soil contamination status assessments suggested a “good state,” and the health risk assessments indicated a “low risk” of Hg and As in the soils of YRD.

The original publication of this paper contains a mistake. Unfortunately, an author was inadvertently missed out, Constanza Arriagada had participated in the operation of the anaerobic digesters cited in the work and now as a PhD student, she is involved in the production of other publication

Plastics are recalcitrant and inert to degrade, and destabilization leads to accumulate in the terrestrial and marine ecosystems; need for the development of strategies for reducing these plastic wastes in a sustainable manner would be revolutionary. We studied the bacterial adherence, degradation and destabilization of polyvinylchloride (PVC), low-density polyethylene (LDPE), and high-density polyethylene (HDPE) by marine bacterial strain AIIW2 by a series of analytical and microscopic observations over 3 months. Based on 16S rRNA gene sequence and the phylogenetic analysis of the strain AIIW2, it showed 97.39% similarity with Bacillus species. Degradation of plastics was determined by the weight loss after 90 days with bacterial strain which detected up to 0.26 ± 0.02, 0.96 ± 0.02, and 1.0 ± 0.01% for PVC, LDPE, and HDPE films, respectively over initial weights. The mineralization of plastic film was found to be maximum in LDPE followed by HDPE and PVC. Bacterial interaction had increased roughness and deteriorated the surface of plastics which is revealed by the scanning electron microscope and atomic force microscope. Bending vibrations of the alkane rock chain (–CH₂ and –CH₃) and carbonyl (–CO) regions in LDPE and HDPE films, while there was slight stretching in the hydroxyl (–OH) regions of carboxylic acid in PVC which is evidenced through Fourier transform infrared spectral studies, suggested the oxidative activities of the bacteria. Though, the bacterial activity was higher on the LDPE and HDPE than PVC film which may be due to the presence of chlorine atom in PVC structure making it more versatile. The results of the present study revealed the ability of marine bacterial strain for instigating their colonization over plastic films and deteriorating the polymeric structure.