Clarifying the occurrence and morphological characteristics of petroleum hydrocarbons (PHs) in soil can facilitate a comprehensive understanding of their migration and transformation patterns in soil/sediment. Additionally, by establishing the dynamic transformation process of each occurrence state, the ecological impact and environmental risk associated with PHs in soil/sediment can be assessed more precisely. The adsorption experiments and closed static incubation experiments was carried out to explore the PHs degradation and fraction distribution in aged contaminated soil under two remediation scenarios of natural attenuation (NA) and bioaugmentation (BA) by exogenous bacteria through a new sequential extraction method based on Tenax-TA, Hydroxypropyl-β-cyclodextrin and Rhamnolipid (HPCD/RL), accelerated solvent extractor (ASE) unit and alkaline hydrolysis extraction. The adsorption experiment results illustrated that bioaugmentation could promote the desorption of PHs in the adsorption phase, and the soil-water partition coefficient Kd decreased from 0.153 L/g to 0.092 L/g. The incubation experiment results showed that compared with natural attenuation, bioaugmentation could improve the utilization of PHs in aged soil and promote the generation of non-extractable hydrocarbons. On the 90th day of the experiment, the concentrations of weakly adsorbed hydrocarbons in the natural attenuation and bioaugmentation experimental groups decreased by 46.44% and 87.07%, respectively, while the concentrations of strongly adsorbed hydrocarbons and non-extractable hydrocarbons increased by 77.93%, 182.14%, and 80.91%, and 501.19%, respectively, compared their initial values. We developed a novel dynamic model and inverted the kinetic parameters of the model by the parameter scanning function and the Markov Chain Monte Carlo (MCMC) method based on the Bayesian approach in COMSOL Multiphysics® finite element software combined with experimental data. There was a good linear relationship between experimental interpolation data and model prediction data. The R2 for the concentrations of weakly adsorbed hydrocarbons ranged from 0.9953 to 0.9974, for strongly adsorbed hydrocarbons from 0.9063 to 0.9756, and for non-extractable hydrocarbons from 0.9931 to 0.9982. These extremely high correlation coefficients demonstrate the high accuracy of the parameters calculated using the Bayesian inversion method.

In this work, soil samples were taken from 15 different sites and the contents of Cd, Cr, Cu, Ni, Pb, and Zn in the mobile and residual fractions of the soils formed from the volcanic materials were determined by the sequential extraction procedure. The mobility of each metal was revealed by analysing fractions. The order of heavy metals in each fraction of Karadağ samples was:Cd: Acid and Water Soluble > Reducible > Oxidizable > Residual; Cr: Residual > Oxidizable > Reducible > Acid and Water Soluble; Cu: Residual > Oxidizable > Reducible > Acid and Water Soluble; Ni: Residual > Reducible > Oxidizable > Acid and Water Soluble; Pb: Reducible > Residual > Oxidizable > Acid and Water Soluble; Zn: Residual > Reducible > Oxidizable > Acid and Water Soluble.According to the results, while the concentrations of Cd and Pb in the mobile fraction were higher than those in the residual fraction, Cr, Cu, Ni and Zn were higher in the immobile fraction. When the higher mobility levels of Cd and Pb are evaluated in terms of environmental pollution and toxicity in soil, these metals have been found to have a higher potential risk than other metals.Cd and Pb are likely to be in close contact with plant roots and thus could potentially affect soil fertility. To avoid threats to productivity and food security in the long term, further trace metal inputs to soils in these areas should be avoided by agricultural management or other means.

The management and prevention of environmental risks associated with spent telecommunications printed circuit boards (STPCBs) is a concerning issue worldwide. Recycling might be proposed as a proper method to overcome this issue. Despite knowing that, choosing a sustainable method is challenging because of STPCBs complexity. This problem was overcome by analyzing STPCBs using different analytical methods and metal speciation. Understanding these data is essential in selection strategies to maximize selective recycling of metals and to minimize environmental impact. This research focused on characterizing STPCBs based on their structural, morphological, physiochemical, surface, and thermal properties. The accurate measurement of metal contents, indicating 187,900 mg kg-1 Cu, 22,540 mg kg-1 Pb, 1320 mg kg-1 Ag, and 205 mg kg-1 Au elements, plus other base metals, revealed a remarkable potential value in STPCBs. The results of structural analyses indicated that the powder has a crystalline structure and consists of Cu, Sn and Pb phases as well as different functional groups. In addition, after evaluating the zeta potential of the sample, the isoelectric pH of the sample was observed to be 5.6, which indicates that the powder particles have a negative surface in an environment with a pH higher than this value. Further, the metal speciation via sequential extraction procedure was performed, which showed that a unique harsh recycling strategy is required due to the stable structure of STPCBs. According to the results of this analysis, the global contamination factor (GCF) value was 83.48, which indicates STPCBs have a high degree of contamination. Leaching tests and environmental criteria were also conducted on this waste. The findings suggest that STPCBs needs pretreatments before landfilling to lower the concentration of toxic metals. Also, waste extraction test was the most aggressive procedure to assess mobility. Achieving this information is considered an essential step to choosing the most efficient recycling methods that minimize environmental impact while maximizing selective recycling of metals.

Understanding the role of N-fixing leguminous trees for phosphorus (P) cycling in highly weathered tropical soils is relevant for the conservation of natural forests as well as the sustainable management of agroforests and forest plantations with low P input in the Brazilian Atlantic Forest region. We hypothesized that N-fixing leguminous trees can increase the availability of soil P by exploiting different P sources without causing a depletion of soil organic P due to efficient biogeochemical cycling, but empirical evidence remains scarce. For this purpose, 31P nuclear magnetic resonance spectroscopy (31P NMR) was used for quantifying soil P forms and the Hedley sequential extraction to determine soil P fractions. The studied sites were forestry systems with leguminous trees: mixed forest plantations with different proportions of fast-growing N-fixing leguminous trees; pure plantations, and agroforestry systems with leguminous trees. The results show that all N-fixing leguminous trees and N mineral fertilization positively affected the concentrations of available soil P in relation to the control treatments. There were increases of all P fractions through cycling in all forest sites. 31P NMR spectra clearly identified and quantified that a large amount of phosphomonoesters followed by phosphodiesters in the form of DNA, as well as high reserves of Pi species (ortho-P and pyrophosphate) in the first eleven years of growth at pure plantations, mixed plantations or agroforests. The relations between both ortho-P and DNA with the resin-Pi, NaHCO3-Pi and NaOH-Pi fractions suggest that both analysis methods provide complementary information about the soil P transformations. Thus, the paper highlights the importance of the use of different N-fixing leguminous tree species under different environmental conditions, production systems and management practices for recovering heavily degraded areas, which may be a suitable strategy through efficient management of P in highly weathered tropical soils in the Brazilian Atlantic Forest biome.

Heavy metals from mines affect the soil and groundwater, and cause and severely impact on the health of local residents. The soil samples were characterized for the distribution and by the chemical speciation method, and then estimated the human health risks of the two mineaffected soils after stabilization process.. Two extraction techniques (Tessier and Wenzel methods) were applied to fractionate metals, such as arsenic (As) and zinc (Zn), to quantify the chemical status of metals in the soils. The mobility of As and Zn was predicted using the ASTM test and sequential extraction (Tessier and Wenzel) method results. The correlation coefficients of As and Zn mobility prediction using Tessier and Wenzel Fraction 1 were 0.920 and 0.815, respectively. The sum of fractions F1 + F2 + F3 showed the highest correlation coefficients value and F value for mobility prediction of both As and Zn. The hazardous indices (HI) for non-carcinogenic risk and carcinogenic risk (CR) to humans were evaluated according to the pseudo-total concentrations of metal in soils. The CR values of carcinogenic for As were within the ranges from 1.38 × 10-4 to 1.25 × 10-3 and 3.71 × 10-4 to 3.35 × 10-3 for both Young Dong (YD) and Dea San (DS), respectively. The HI for non-carcinogenic risk was the highest for As in the YD (2.77) and DS (7.46) soils, which covered approximately 96 and 84% of HI, respectively. In summary, the contribution of As to risk from heavy metals was dominant.

Sedimentary As, Fe and Mn species in core sediments from the Danshuei Estuary, an anoxic estuary, were studied using a five-sequential extraction method followed by chemical analyses of these elements. The sediment texture, redox potential and dissolved concentrations of these elements in pore water were also determined. Dissolved As diffusion flux was also calculated. Higher concentrations of sedimentary As were found at the middle and lower estuary stations. The sedimentary As species in the samples were dominated by three fractions: amorphous and poorly-crystalline; and well crystallized hydrous oxides of Fe and Al; and residual phases, accounting for 90% of the total As pool. The geochemical behavior of sedimentary As in the Danshuei Estuary is strongly influenced by the redox potential and Fe oxides. The dissolved As concentrations in pore water correlated inversely with the redox potential. The sediment served as a source of dissolved As and the diffusion flux ranged from 0.047-0.35 μg cm(-2) y(-1).

The general aim of this work has been to check the ecological impact of metals on the Ebro river basin. In order to evaluate this, metal behavior considering water, sediment as well as metal bioaccumulation in fish has been studied. Total concentrations of metals, as well as the potentially bioavailable fraction of metals in sediment has also been analyzed by the application of the sequential extraction method (BCR method). In order to evaluate the influence of metal pollution on the river ecological status, according to the Water Framework Directive (WFD), diverse biological indices such as macroinvertebrates (IBMWP), diatoms (IPS) and macrophytes (IVAM), have been considered from an integrated point of view. Considering both water and sediment, metals which contributed in higher extend to the reduction of biological quality have been demonstrated to be Pb and Zn, as they presented a negative influence on macroinvertebrates, diatoms and macrophytes communities. As and Cr that seemed to have a significant influence on macroinvertebrates and diatoms too, while Ni negatively influenced only diatom communities. This study also demonstrated that monitoring programs only based on total metal determination in water are inefficient, as metals present even at undetectable concentrations in water are strongly accumulated in fish. Moreover, the high concentrations of Hg found in sediments indicated that this river basin may present pollution problems regarded to this metal, as demonstrated by the high Hg levels found in fish.

METHODS: The growing world population requires the exploration of new sustainable protein sources to ensure food security. Insects such as mealworm are promising candidates. For safety reasons, a risk assessment, including allergy risks, is needed. Since allergenicity can be influenced by thermal processing, it is highly important to take this into account.
RESULTS: Fresh mealworm was heat processed and extracted by a sequential extraction method using in succession Tris, urea, and a combined SDS/DTT buffer. Extracts were tested using immunoblot, basophil activation test and skin prick test in 15 shrimp allergic patients, previously indicated as population at risk for mealworm allergy. Immunoblots showed a difference in IgE binding between processed and unprocessed mealworm extracts. However, this was due to change in solubility. Some allergens were soluble in urea buffer, but became more soluble in Tris buffer and vice versa. IgE binding was seen for all extracts in blot and basophil activation test. The results from 13 skin prick tests showed a skin reaction similar between processed and unprocessed mealworm.
CONCLUSIONS: Thermal processing did not lower allergenicity but clearly changed solubility of mealworm allergens. A sequential extraction method allowed for assessment of a broader protein panel.

A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L(-1) for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013-0.800, 0.011-0.900 and 0.079-1.400 mg L(-1) for F1, F2, and F3, respectively. The precision of the automated MSFIA-HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L(-1) As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from an arsenic-contaminated mining zone to evaluate its extractability. The frequency of analysis of the proposed method was eight times higher than that of the conventional BCR method (6 vs 48 h), and the kinetics of lixiviation were established for each fraction.