Soil erosion constitutes a serious threat for sustainable agriculture in many countries. Magnetic susceptibility of soil is a fast, cheap, and non-destructive technique that could be used to quantify soil erosion or soil redistribution on a long-term scale. This study attempts to analyze the variation of magnetic susceptibility in soil profiles having the same lithology and climatic conditions, but different land uses and slope gradients in a subcatchment in northern Morocco. Soil cores were collected on forested, cultivated, and pasture lands. Each core was associated to a field unit (also called a homogeneous unit) characterized by a set of four cited erosion factors. The samples were measured for mass–specific low-frequency magnetic susceptibility (χₗf) and frequency-dependent magnetic susceptibility (χfd). The linear correlation of χₗf and χfd indicates the homogeneity of magnetic population in soil. It supports the use of empirical models based on comparisons of χₗf to predict the value of magnetic parameter after tillage homogenization and removal of soil material from the surface, and to estimate soil erosion or redeposition. The study built a methodology improving these empirical models and enabling a quantitative approach of the phenomenon. Two models, namely “tillage homogenization” (as improved in this study) and the proposed “simple correlation” result in globally similar estimates of erosion, while another model, the “simple proportional” model, underestimates it. The results give an estimate of long-term erosion (deposition) in sampled units and allow drawing of an areal soil redistribution map in the watershed.

The use of pesticides has been increasing in agriculture, leading to a public health problem. The aim of this study was to evaluate ototoxic effects in farmers who were exposed to cigarette smoke and/or pesticides and to identify possible classification patterns in the exposure groups. The sample included 127 participants of both sexes aged between 18 and 39, who were divided into the following four groups: control group (CG), smoking group (SG), pesticide group (PG), and smoking + pesticide group (SPG). Meatoscopy, pure tone audiometry, logoaudiometry, high-frequency thresholds, and immittance testing were performed. Data were evaluated by artificial neural network (ANN), K-nearest neighbors (K-NN), and support vector machine (SVM). There was symmetry between the right and left ears, an increase in the incidence of hearing loss at high frequency and of downward sloping audiometric curve configuration, and alteration of stapedial reflex in the three exposed groups. The machine-learning classifiers achieved good classification performance (control and exposed). The best classification results occur in high type (I and II) datasets (about 90% accuracy) in k-NN test. It is concluded that both xenobiotic substances have ototoxic potential; however, their combined use does not present additive or potentiating effects recognizable by the algorithms.

Dibutyl phthalate (DBP), a persistent environmental pollutant, can induce neural tube abnormal development in animals. The possible effects of DBP exposure on human neural tube defects (NTDs) remain elusive. In this study, the distribution of DBP in the body fluid of human NTDs was detected by GC-MS. Then, chick embryos were used to investigate the effects of DBP on early embryonic development. Oxidative stress indicators in chick embryos and the body fluid of human NTDs were detected by ELISA. The cell apoptosis and total reactive oxygen species (ROS) level in chick embryos were detected by whole-mount TUNEL and oxidized DCFDA, respectively. The study found that the detection ratio of positive DBP and its metabolites in maternal urine was higher in the NTD population than that in normal controls. 8-hydroxy-2 deoxyguanosine (8-OHDG) and malondialdehyde (MDA) were evidently upregulated and superoxide dismutase (SOD) was observably downregulated in amniotic fluid and urine. Animal experiments indicated that DBP treatment induced developmental toxicity in chick embryos by enhancing the levels of oxidative stress and cell apoptosis. MDA was increased and SOD was decreased in DBP-treated embryos. Interestingly, the supplement of high-dose choline (100 μg/μL), not folic acid, could partially restore the teratogenic effects of DBP. Our data collectively suggest that the incidence of NTDs is closely associated with DBP exposure. This study may provide new insight for NTD prevention.

Stabilization and solidification (s/s) of heavy metals by cementitious materials are one of the effective methods in hazardous waste management. In cement alkaline environment, Cr(VI) compounds appear in the form of chromate anion (CrO₄⁻²), which is highly soluble; it makes the implication of the s/s method challenging. Therefore, it is important to study the amount of chromium leaching from cementitious materials. The effects of Cr(VI) concentration and water-to-cement (w/c) ratio on the level of leaching of chromium from cement mortar (CM) were investigated in this study. Results indicated w/c not significantly affect the leaching of chromium in the age of 28-day but in the 90-day-old samples indicated a reduction in leaching of chromium from mortar with increasing w/c. Results from toxicity characteristic leaching procedure (TCLP) tests indicated that the efficiency of Cr(VI) stabilization was reduced with greater chromium content but was enhanced with increased w/c. In detail, results showed that only about 0.21% and 0.26% cement weight in TCLP and tank test of Cr(VI) was stabilized in CM, respectively. The results of X-ray diffraction (XRD) and scanning electron microscope (SEM/EDS) tests indicated that increasing the Cr(VI) content leads to changes in the formation of the cement main phases and microstructure of CM.

In this study, the efficiency of electrochemical oxidation to treat a sanitary landfill leachate was evaluated by the reduction in physico-chemical parameters and in ecotoxicity. The acute toxicity of the sanitary landfill leachates, before and after treatment, was assessed with the model organism Daphnia magna. Electrochemical oxidation treatment was effective in the removal of organic load and ammonium nitrogen and in the reduction of metal ions concentrations. Furthermore, a reduction of 2.5-fold in the acute toxicity towards D. magna after 36 h of treatment was noticed. Nevertheless, the toxicity of the treated leachate is still very high, and further treatments are necessary in order to obtain a non-toxic effluent to this aquatic organism. Toxicity results were also compared with others described in the literature for different leachate treatments and test organisms.

Cadmium (Cd) soil contamination poses a major hazard to safe food production throughout the world, calling upon actions for decontamination using environmentally friendly methods, such as phytoextraction. In this study, the capability of chive (Allium schoenoprasum L.) for phytoextracting Cd from contaminated soils was tested. Growth of chive was studied in a soil spiked with 0, 15, 30, 60, and 120 mg Cd/kg soil, and then, concentrations of Cd in soil, plant shoots, and roots were measured after harvest. Chive dry matter production was not affected significantly by the different Cd levels in soil, except from the maximum Cd concentration (120 mg Cd/kg soil), where dry matter was reduced by 77%. Cadmium accumulation occurred mostly in roots rather than in shoots, with maximum Cd concentrations 482.48 and 26.65 mg/kg of dry matter, respectively. Translocation factor (the proportion of Cd concentration in the aerial plant parts to that in the roots) was below 1 in all contaminated levels and decreased with increasing Cd concentrations in soil, indicating low Cd reallocation from roots to shoots. Maximum amount of Cd absorption (Cd concentration in shoots), maximum contaminant uptake rate, and minimum clean-up time were all observed in Cd concentration 60 mg/kg soil. Based on chive potential to acquire Cd in its roots and shoots, it can be designated as a convenient species for reducing Cd from contaminated soils up to concentrations of 60 mg Cd/kg soil.

As the largest oil field in China, Daqing oil field has been developed in the past six decades. The objectives of this study were to measure the levels of polycyclic aromatic hydrocarbons (PAHs) and assess their ecological risk of PAHs in vegetation soil and bare soil near oil well in Daqing and surrounding soil. Ten sites were selected from two types of soil in grassland: vegetation soil (VS, n = 5) and bare soil (BS, n = 5). The mean concentration of 16 PAHs (∑₁₆ PAHs) was 2240.2 μg/kg. The mean concentrations of eight carcinogenic PAHs (∑₈c PAHs) was 1312.3 μg/kg which accounts for 59% of ∑₁₆ PAHs. The sampling sites had higher proportions of high weight molecular ringed PAHs with higher proportions of benzo (a) pyren (BaP) and benzo (k) fluoranthene (BkF). The main source of PAHs was petroleum, coal/biomass combustion, and vehicular emission in these sampling sites. According to Canadian soil quality guidelines, 60% sites had a significant risk to human health. Moreover, 50% sites had high ecological risk and 30% sites were close to this critical value. Notably, PAH levels were significantly higher in VS than BS; moreover, VS had higher organic matter (OM) content, soil dehydrogenase (sDHA) activity, and lower pH and salt content. A structural equation model was established to explore the effects of soil properties on PAH concentration in VS. The result revealed that OM and sDHA were meaningful to enhance the adsorption and biological fixation of PAHs. This study will provide basic information on PAH level and potential application for phytoremediation.

Economic policy uncertainty (EPU) will affect the external business environment of economic entities, which in turn affects the decision-making of economic entities. Meanwhile, carbon emissions are closely related to the production decisions of microeconomic entities. Thus, studying the relationship between EPU and carbon emissions helps to clarify the impact of institutional factors behind carbon emissions, which is significant for achieving green development. Based on US sector data, we apply a novel parametric test of Granger causality in quantiles to analyze the relationship between EPU and carbon emissions (its growth and uncertainty). We find that there is an outstanding pattern of Granger-causality from the US EPU to the growth of carbon emissions in the tails of the growth distributions of carbon emissions in the industrial sector, residential sector, electric power sector, and transportation sector, except in the commercial sector. That is, carbon emissions are affected by EPU when the growth of carbon emissions is in a higher or lower growth period. Lastly, we find that the US EPU affects carbon emissions uncertainty over the entire conditional distribution for all sectors.

In this study, a sampling campaign was conducted for 29 buildings on the National Taiwan University (NTU) campus where lead pipes were present in 4 buildings. Total lead, soluble lead, and water quality parameters including pH, temperature, residual free chlorine, and total organic carbon were measured. Results from the first-round sequential sampling (10 × 100 mL) showed that the presence of lead pipe did not necessarily cause elevated lead levels. However, the highest lead concentration and the highest frequency of exceeding 10 μg/L were detected in a building with lead pipe. Faucet was identified to be a major lead source in at least 8 buildings. No significant correlations between lead levels and water parameters were found. The building showing the highest lead level in the first round was sampled for a second round using four different methods, namely, first draw sampling, random daytime sampling, sequential sampling (5 × 1 L), and flushing sampling. Lead levels in samples collected using the four sampling methods all exceeded 10 μg/L. The first draw sampling showed the highest lead level, followed by comparable levels for random daytime sampling and sequential sampling. Flush sampling yielded the lowest lead concentration. Particles collected from the faucet aerators in 14 buildings were also characterized for their compositions and lead contents.

Seedlings of ‘Shatian pummelo’ (Citrus grandis) and ‘Xuegan’ (Citrus sinensis) were supplied daily with nutrient solution at a concentration of 0.5 (control), 100, 200, 300, 400, or 500 μM CuCl₂ for 6 months. Thereafter, seedling growth; leaf, root, and stem levels of nutrients; leaf gas exchange; levels of pigments; chlorophyll a fluorescence (OJIP) transients and related parameters; leaf and root relative water content; levels of nonstructural carbohydrates; H₂O₂ production rate; and electrolyte leakage were comprehensively examined (a) to test the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth; (b) to establish whether the Cu-induced preferential accumulation of Cu in the roots is involved in Cu tolerance of Citrus; and (c) to elucidate the possible causes for the Cu-induced decrease in photosynthesis. Most of the growth and physiological parameters were greatly altered only at 300–500 μM (excess) Cu-treated seedlings. Cu supply increased the level of Cu in the roots, stems, and leaves, with a greater increase in the roots than that in the stems and leaves. Many of the fibrous roots became rotten and died under excess Cu. These findings support the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth, and the conclusion that the preferential accumulation of Cu in the roots under excess Cu is involved in the tolerance of Citrus to Cu toxicity. The lower CO₂ assimilation in excess Cu-treated leaves was caused mainly by nonstomatal factors, including structural damage to thylakoids, feedback inhibition due to increased accumulation of nonstructural carbohydrates, decreased uptake of water and nutrients, increased production of reactive oxygen species, and impaired photosynthetic electron transport chain. Also, we discussed the possible causes for the excess Cu-induced decrease in leaf pigments and accumulation of nonstructural carbohydrates in the roots and leaves.