Dibutyl phthalate (DBP), as a plasticizer, is widely used in China, and it is easily released into diverse environments. In this study, we have obtained a stable bacterial consortium (B1) enriched from municipal sewage treatment plant activated sludge. The obtained bacterial consortium B1 was capable of degrading DBP and was mainly composed of Pandoraea sp. and Microbacterium sp. From the initial concentrations of 35–500 mg L⁻¹, DBP was efficiently degraded by the consortium, with the degradation rates above 92% within 3 days. The optimal temperature for DBP degradation was 30 °C and consortium B1 could adapt to a wide range of pH (5.5–8.5). The analysis of Illumina sequencing further showed that the relative abundance of Pandoraea was increased at the beginning of the degradation, while Microbacterium was decreased. In the later stage of the degradation, the change of the relative abundance of Pandoraea and Microbacterium was opposite. Apart from DBP, consortium B1 could also utilize dimethyl phthalate (DMP), di-2-ethylhexyl phthalate (DEHP), and phthalic acid (PA) as the sole carbon. Moreover, adding B1 to DBP-contaminated soil could greatly improve the removal rate of DBP, suggesting that B1 has a great potential for the bioremediation of DBP-contaminated environments.

In this study, rapid decolorization of azo dyes was achieved by in situ-generated green tea extract-iron (GTE-Fe) chelate for the first time. When changing reaction conditions from the aerobic condition to the anaerobic condition, the decolorization efficiencies of two azo dyes, i.e., acid orange 7 (AO7) and acid black 1 (AB1), increased from 46.38 and 83.17 to 90.13 and 95.37%, respectively. The recalcitrant AO7 was then selected as the targeting pollutant in subsequent optimization and mechanism studies. Experimental evidences showed that the initial concentrations of AO7, Fe(III), and GTE are the key factors to optimize the decolorization efficiency. Further characterization studies by spectroscopic analysis, including FESEM, FTIR, and XPS, suggested that the major mechanism of AO7 decolorization is the nucleophilic attack of the oxygen in green tea polyphenols (GTP), and this attack could be facilitated by the organometal chelation. This study provided an efficient and environmental friendly strategy to decolorize azo dyes via in situ generation of the GTE-Fe chelate, as well as its mechanistic insights, shedding lights on in situ remediation of azo dye pollution. Graphical abstractᅟ

A dual-permeability hydro-biodegradation model is developed to describe the leachate flow in municipal solid waste (MSW) and predict the long-term settlement induced by biodegradation in bioreactor landfills. The model is verified against Hydrus-1D and a recirculation experiment conducted in a full-scale landfill. Preferential flow and mass transfer between fissure and matrix can be reasonably modeled by the proposed model. A higher recirculation flow rate can speed up the stabilization process of landfill. However, too much recirculation leachate is not economical and environmental friendly. A stabilization speed index and a leachate utilization index are adopted to evaluate the stabilization speed of bioreactor landfill and utilization rate of leachate, respectively, and the optimal recirculation flow rate is estimated. A flow rate of q = 5 × 10⁻⁵–5 × 10⁻⁴ m/h (equivalent to recirculation intensity of Q = 15–150 L/tonwₐₛₜₑ/year) is recommended for recirculation, which has been verified by the field data in numerous bioreactor landfills.

To explore the main controlling factors in soil and build a predictive model between the lead concentrations in earthworms (Pbₑₐᵣₜₕwₒᵣₘ) and the soil physicochemical parameters, 13 soils with low level of lead contamination were used to conduct toxicity experiments using earthworms. The results indicated that a relatively high bioaccumulation factor appeared in the soils with low pH values. The lead concentrations between earthworms and soils after log transformation had a significantly positive correlation (R² = 0.46, P < 0.0001, n = 39). Stepwise multiple linear regression analysis derived a fitting empirical model between Pbₑₐᵣₜₕwₒᵣₘ and the soil physicochemical properties: log(Pbₑₐᵣₜₕwₒᵣₘ) = 0.96log(Pbₛₒᵢₗ) − 0.74log(OC) − 0.22pH + 0.95, (R² = 0.66, n = 39). Furthermore, path analysis confirmed that the Pb concentrations in the soil (Pbₛₒᵢₗ), soil pH, and soil organic carbon (OC) were the primary controlling factors of Pbₑₐᵣₜₕwₒᵣₘ with high pathway parameters (0.71, − 0.51, and − 0.49, respectively). The predictive model based on Pbₑₐᵣₜₕwₒᵣₘ in a nationwide range of soils with low-level lead contamination could provide a reference for the establishment of safety thresholds in Pb-contaminated soils from the perspective of soil-animal systems.

We aimed to assess the relationship of urine phthalate metabolite concentrations with anthropometric indices, and blood pressure in first-grade children. We detected 11 phthalate metabolites in urine and estimated anthropometric indices, including skinfold measurements, waist circumference (WC), and body mass index (BMI) in 276 children aged 6–8 years. Multivariate linear regression models were used to assess the associations between urinary phthalate metabolite levels, and anthropometric and blood pressure indices in a gender-specific manner. In boys, a 1-ng/mL increase in monobenzyl phthalate (MBzP) concentration was associated with a 0.027-cm decrease in the skinfold measurement (95% confidence interval [CI], − 0.053 to 0.001), whereas a 1-ng/mL increase in mono-ethyl-phthalate (MEP) concentration was associated with a 0.016-mm Hg decrease in systolic blood pressure (95% CI, − 0.031 to 0.001). MBzP, mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and MEOHP concentrations were also inversely associated with WC. However, in girls, MEP concentrations were positively associated with chest measurements, but were inversely associated with WC. A 1-ng/mL increase in monomethyl phthalate concentrations was associated with a 0.039-cm increase in skinfold measurements (95% CI, 0.002 to 0.076), whereas a 1-ng/mL increase in MECPP concentrations was associated with a 0.050 cm decrease in skinfold measurements (95% CI, − 0.095 to − 0.005). In this exploratory, cross-sectional analysis, we identified various interesting associations between different phthalate metabolite levels and anthropometric indices, which suggest that some of phthalate metabolite should be considered in addition to the prevalence rates of overweight and obesity.

Lead (Pb) is a highly toxic metal that damages normal plant metabolism and often results in reduced crop growth and yield. To measure whether or not ultrasonic seed (US) treatment alleviates Pb stress in rice, the seeds of two rice cultivars, i.e., Guangyan1 and Huahang31, were exposed to 30 min of ultrasonic vibration and then the seedlings were transplanted to Pb-contaminated soil. Results revealed that the Pb contents in roots, stems, leaves, panicles (at heading), and brown rice (at maturity) were lower in US treatment than control (CK; without US treatment); the trend for accumulation of Pb in different plant parts was recorded as: root ˃ stems ˃ leaves ˃ panicles ˃ brown rice in both rice cultivars. Overall, the Pb contents in the brown rice of Huahang31 were higher than those in Guangyan1. Moreover, the contents of proline and soluble protein as well as the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were significantly higher while the malondialdehyde (MDA) contents were significantly reduced in US treatment compared to CK. The effective panicle number, seed set percentage, grains per panicle, 1000-grain weight, and grain yield were increased by 8.9%, 5.3%, 6.8%, 4.4%, and 26.6% in Guangyan1 and 3.2%, 5.7%, 5.7%, 5.0%, and 24.2% in Huahang31, respectively in US treatment compared to CK. Hence, seed treatment with ultrasonic waves could improve rice performance and reduce brown rice Pb accumulation under Pb-polluted soils.

The aim of this study was to evaluate the differences between concentrations of heavy metals (cadmium, copper, zinc, iron, and manganese) in terrestrial gastropods, Helix pomatia, collected in four different environment locations in Pančevo city, Serbia. Metal concentrations in the foot and in the digestive gland were measured. Heavy metals cadmium, copper, zinc, iron, and manganese were measured in triplicate by atomic absorption spectrophotometry. Also, this study investigated correlations between the trace element content in the soft tissues and different seasons (summer and fall). The results showed that heavy metal concentrations of the measured elements in both snail tissues were significantly higher in polluted sites when compared to the background levels in the city. In digestive gland tissues, the concentration of heavy metals was higher compared with that in foot tissues. The bioaccumulation (heavy metal concentrations in soft tissues) of heavy metals (Cd, Cu, Zn, Fe, and Mn) in snails, Helix pomatia, has been assessed and related to seasons and sites. Heavy metal accumulation in the soft tissues of snails could provide a powerful monitoring tool for the assessment of environmental heavy metal pollution.

Sponge iron particles modified with expanded graphite and Cu were used to purify solutions contaminated with aqueous Cr(VI). A removal mechanism that involved physical adsorption and a redox reaction is proposed. The reaction, which consisted of rapid adsorption, a desorption stage, and an adsorption–desorption equilibrium stage, corresponded to a first-order kinetic model. The properties of the adsorption materials before and after use were investigated by X-ray diffraction, scanning electron microscopy–energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray fluorescence spectroscopy, and surface area measurements. Changes in the surface properties, e.g., attachment of material to the surface and filling of pores with Cr, were clearly observed. The Langmuir model best described Cr(VI) adsorption on the sponge iron and its modified particles. Removal efficiencies of 98.7, 98.8, and 100% were achieved in 7 h at a Cr(VI) dosage of 10 mg/L. Sponge iron particles are therefore potential adsorbents and after modification give good removal of Cr(VI) ions from contaminated water.

Oestrogens participate in various biological processes such as oogenesis, vitellogenesis and testicular development, but studies regarding the distribution and protein levels of oestrogen receptors (ERα and ERβ) and aromatase (Cyp19) in testis are rarely investigated in fish species. The aim of the present study was to analyse the expression pattern of ERα, ERβ and Cyp19 in testis of Astyanax rivularis and, in addition, to verify if oestrogenic contamination interferes in the expression levels of these proteins. Quarterly, field samplings were carried out during a reproductive cycle in a stream of the Upper Velhas River with a good conservation status (site S1). In the gonadal maturation peak (June), when ripe stage was most abundant, fish collection was made in three streams: S1, reference site, and S2 and S3, sites contaminated by untreated sewage. The results of immunohistochemistry demonstrated labelling of Cyp19 in Leydig cells and acidophilic granulocytes, but spermatogonia, Sertoli cells, spermatids and spermatozoa were also labelled. ERα was more widely distributed than ERβ being found in all developmental germ cell phases. On the other hand, ERβ was found only in spermatogonia and spermatocytes. During testicular maturation, ELISA levels for Cyp19, ERα and ERβ followed the gonadosomatic index (GSI) with significant higher values in the ripe stage. Regarding to endocrine disruption, the males exposed to domestic sewage presented significant higher expression of Cyp19 and ERα when compared to the non-exposed fish. Together, our results demonstrate expression patterns of Cyp19, ERα and ERβ in the testis of A. rivularis. In addition, we indicate ERα and Cyp19 as sensitive biomarkers for monitoring of oestrogenic contamination in freshwater environments.

Initial point pollutant transport in wetland flows acts as a typical form in various applications. Accurate determination of the basic characteristics for dispersion fundamentally supports the predication of pollutant transport especially in the transient stage. This work analytically studies the transient dispersion of an initial point pollutant concentration in wetland flows through the phase average technique and the method of concentration moments. The characteristics including the vertical mass distribution, longitudinal displacement, dispersivity, skewness, and kurtosis corresponding to the zeroth- to fourth-order concentration moments are accurately illustrated in their full-time dependance for the first time. Present results show to be distinctive from those of initial uniform concentration in the transient dispersion process. The temporal evolutions of the five characteristics are all dependent of the initial point release position. The results further demonstrate that the timescale 3.0 as measured by the skewness, rather than 0.5 as measured by the dispersivity, should be characterized as the transient period for the dispersion of initial point concentration in comparison with that of initial uniform. Furthermore, the longitudinally distributed mean concentration is as well analyzed through the Hermite polynomials. The results imply that strict criteria for environmental and ecological implications should be established by further accounting for the five characteristics.