Conventional wastewater treatment plants (WWTPs) are not able to remove completely some emerging contaminants, such as residual pharmaceutical compounds (PCs) with potential ecotoxicity to water bodies. An advanced bio-oxidation process (ABOP) using white-rot fungi (WRF) has been proposed as alternative biological treatment for degradation of non-biodegradable compounds. A synthetic and real wastewater spiked with 12 PCs at 50 μg L⁻¹ was treated by means of ABOP based on WRF in a rotating biological contactor (RBC) at 1 day of hydraulic retention time (HRT). The ABOP achieved a remarkable biological performance in terms of TOC removal and reduction of N-NH₄⁺ and P-PO₄³⁻ nutrients. Likewise, 5 of the 12 PCs were eliminated with removal efficiencies ranging from 80 to 95%, whereas 6 of 12 PCs were eliminated with removal values ranging from 50 to 70%. The anaerobic digestion of the fungal sludge generated upon the treatment was also evaluated, obtaining a methane yield of 250 mL CH₄ gVS⁻¹. These results evidenced that the proposed ABOP is a promising alternative for the sustainable wastewater treatment of urban effluents, combining advanced oxidation with biological operation for the removal of emerging PCs and energy recovery.

Chromium (Cr) pollution is at a worrying level in a region of oilseed rape production in China. Sulfur (S) is an indispensable element for plants that has been confirmed to play an important role in regulating plant response to heavy metal stress. The present study was conducted to examine the role of S in alleviating Cr toxicity in oilseed rape. Cr stress strongly induced oxidative stress and inhibited plant growth. Application of S significantly enhanced the tolerance of oilseed rape exposed to Cr stress by activating several detoxification mechanisms including the ascorbate-glutathione (AsA-GSH) enzyme defense system and GSH production. The Cr and phytochelatins (PC) contents in the root under S treatment were markedly higher than those under Cr stress. The transcript abundances of the heavy metal transporters HMA2 and HMA4 were lower under S treatment than under Cr treatment. Most Cr was restricted to roots, and the translocation factor (TF) of Cr was markedly decreased in oilseed rape. In conclusion, our study revealed that S application is advantageous to oilseed rape defense against Cr toxicity and inhibits Cr translocation from roots to shoots.

Phosphorus (P) in sewage sludge (SS) has been a concern for decades. Sludge-borne P could exacerbate eutrophication problems once released to aquatic environments. Meanwhile, sludge-borne P would be a valuable alternative source to P minerals. A comprehensive understanding of the occurrence forms and fate of P in SS is required prior to the assessment of environmental implications of sludge-borne P. In the present study, we conducted a nationwide survey on speciation of phosphorus in the SS of China. The average concentration of total phosphorus (TP) in SS was 17.3 ± 5.1 g· kg⁻¹, of which 67.1 ± 8.9% occurred as inorganic forms. Non-apatite inorganic phosphorus constituted the major component (77.6 ± 11.4%) of inorganic phosphorus, with the rest minor portion occurring as apatite phosphorus. Organic P accounted for 26.8 ± 7.9% of TP in SS, showing an average concentration of 4.5 ± 4.2 g· kg⁻¹. Majority of phosphorus in the SS of China occurs as labile forms, suggesting that the environmental implications of SS disposal approaches should be assessed seriously. Sewage sludge produced by China contained 1.1 × 10⁵ t of TP in 2016, and the amount accumulated to 1.0 × 10⁶ t since 2001. Landfill sites are the single most important fate, receiving 8.1 × 10⁵ t of sludge-borne TP since 2001. Land application and building materials are the other two fates of sludge-borne phosphorus. Spatial-temporal variations of phosphorus in the SS of China were also discussed. Graphical abstract

In large urban centers, the toxicity of metal mixtures may be enhanced by physicochemical factors and environmental variables, including pH. Rio Grande, a municipality located in the extreme south of Brazil, has soils with high levels of contamination due to urban and industrial activities and a high prevalence of acid rain events. Previous studies have shown that contact with elutriate of these soils can cause physiological and reproductive changes. Thus, the objective of the present study was to evaluate, through animal experimentation, the effects of a metal-contaminated soil, acidified by hydrofluoric acid at two different pH values (5.2 and 3.6), on the health of offspring of rats exposed during gestation and lactation. Female Wistar rats were gavaged daily for 42 days (gestation and breastfeeding) with soil elutriate contaminated with metals, using solvent with different pH values (6.0, 5.2, and 3.6). The following parameters were evaluated in their offspring: body and organ weight, length, appearance of developmental characteristics, and swimming. Experimental groups in which the progenitors were exposed to the solution at pH 3.6 exhibited a delayed increase in weight as well as motor deficit, with a decreased weight (onset) and length (beginning and end), while exposure in association with soil was an aggravating factor for the damages to the body. Exposure to the solution at pH 5.2 decreased the initial weight of the animals, impaired some parameters of weight development, and caused motor deficit on the 14th day. These novel findings reveal that the exposure of progenitors to environmental stressors can compromise the health of the offspring. Special attention should be given to populations living in areas with high prevalence of acid rain.

Evaluation of oxygen distribution during aeration in landfill is significantly important to determine the design parameters of an injection well. A coupling model describing gas preferential transport in a landfill was developed, which linked the effect of advection–diffusion and oxidation reaction and mass exchange between the fracture and the matrix system. The quantitative simulation of the variation in gas distribution during vertical well aeration in short term was presented, combined with the typical cases in field site. The parameter sensitivity in the coupling model to gas transport was addressed. Simulation result of the oxygen and methane concentrations by using the dual advective–diffusive (DAD) model, which considered the immobile zone effect, was closer to the monitoring data than that by using single advective–diffusive model. The variation of the AR under aeration was presented with the key parameters to provide the theory evidence for gas well design in landfill. This study provided reference for the design of the gas injection well distribution in aerobic landfill.

We investigated physiological responses of 7-week-old Norway spruce seedlings to water deficits of different intensities. Hydroponically grown seedlings were subjected to mild (−0.15 MPa), strong (−0.5 and −1.0 MPa) and extreme (−1.5 MPa) water deficit induced by polyethylene glycol 6000, and their growth parameters, water status and physiological activity were analyzed. Seedlings effectively restricted water loss under drought, and even under extreme water deficit, shoot relative water content did not fall below 85%. Water stress induced substantial decreases in the osmotic potentials of root and needle cell sap, up to 0.3–0.4 MPa under extreme water deficit, though this did not result from water loss or accumulation of K⁺ and Na⁺ ions. Seedling growth was very susceptible to water stress because of poor capacity for cell wall adjustment. Water stress injured seedling roots, as evidenced by the loss of root cell physiological activity estimated by the ability to hydrolyse fluorescein diacetate and by increased root calcium content up to 8–10-fold under extreme water stress. At the same time, root hair growth was enhanced, especially under mild water deficit, which increased the root water-absorbing capacity. In summary, seedlings of Norway spruce were characterized by high susceptibility to water stress and concurrently by pronounced ability to maintain water status. These characteristics are fully consistent with spruce confinement to moist habitats.

Biochar application to soil is currently widely advocated for a variety of reasons related to sustainability. However, the synergistic effects of biochar combined with mineral or organic fertilizer on soil N₂O emissions, NH₃ volatilization, and plant N uptake are poorly documented. Field plot experiments planted with peanut were conducted under the application of biochar (derived from rice husk and cottonseed husk, 50 t ha⁻¹) with organic or mineral fertilizer. It was found that biochar increased soil nutrient availability and decreased surface soil bulk density, demonstrating that biochar could improve the soil quality especially in the 0–20-cm profile. The total N content of the plant changed little with treatments, but the kernel N concentration increased significantly when biochar was applied with organic fertilizer. Peanut yield increased with biochar amendment while no significant difference was observed in plant biomass, suggesting biochar had a positive effect on belowground biomass. Peanut N uptake was also increased following biochar amendment with either organic or mineral fertilizers. While biochar amendment had no significant effect on soil NH₃ volatilization, it did decrease the cumulative N₂O emission by 36.3% on average with organic fertilizer, and by 32.6% with mineral fertilizer, respectively (p < 0.05). The copy numbers of 16S rDNA, nifH, nirK, and nirS were not influenced by the application of biochar; however, the copy number of nosZ was significantly increased under biochar plus mineral fertilizer treatment. The results imply that biochar application can suppress N₂O emissions, as a result of abiotic factors and enhanced peanut N uptake rather than changes of denitrification genes.

Due to limits on available data, the effects of urban sprawl on regional nonpoint source pollution (NPS) have not been investigated over long time periods. In this paper, the characteristics of urban sprawl from 1999 to 2014 in Beijing were explored by analyzing historical land-use data. The Event Mean Concentration data have been collected from all available references, which were used to estimate the variation in urban NPSs. Moreover, the impacts of variation in urban sprawl on regional NPSs were qualified. The results indicated that the urbanization process showed different influences on pollutants, while COD and TN were identified as key NPS pollutants. Residential areas contributed more NPS pollutants than did roads, which played a tremendous role in the control of urban NPS. The results also suggested in part that the impact of urban sprawl on the variation of COD decreased while TN increased in Beijing during the study period. These results would provide insight into the impacts of urban sprawl on NPS variation over a long period, as well as the reference for reasonable urban planning directives.

Surface waters are likely to be contaminated by both pesticides and fertilizers. Such contamination can result in changes in community composition if there is differential toxicity to individual taxa. We conducted a fully factorial mesocosm experiment that examined the single and interactive effects of environmentally realistic concentrations of nitrate and malathion on zooplankton communities and phytoplankton productivity. Malathion significantly decreased the abundance of total zooplankton, cyclopoid copepods, copepod nauplii, and Ceriodaphnia, and increased the abundance of rotifers. Nitrate addition generally had no effect on zooplankton; however, Ceriodaphnia abundance was higher in control mesocosms than in nitrate-treated mesocosms. There was only one significant interaction between malathion and nitrate treatments: For Ceriodaphnia, the no malathion, no nitrate mesocosms had much higher abundances than all other combinations of treatments. Without nitrate addition, chl a levels were uniformly low across all malathion treatments, whereas in the presence of nitrate, there were differences among the malathion treatments. In conclusion, our results demonstrate that malathion contamination of aquatic ecosystems can result in changes in the abundance and composition of zooplankton communities. In contrast, nitrate contamination appeared to have much less potential impact on zooplankton communities, either on its own or in interaction with malathion. Our results reinforce the notion that the effects of contaminants on aquatic ecosystems can be complex and further research examining the single and interactive effects of chemical stressors is needed to more fully understand their effects.

There is growing interest in low-cost, efficient materials for the removal of organic contaminants in municipal and industrial effluents. In this study, the efficiency of biochar and activated biochar, as promising adsorbents for phenol removal, was investigated at high (up to 1500 mg L⁻¹) and low concentrations (0.54 mg L⁻¹) in synthetic and real effluents (from wood-residue deposits in Québec), respectively. The performance of both materials was then evaluated in batch adsorption experiments, which were conducted using a low solid/liquid ratio (0.1 g:100 mL) at different phenol concentrations (C₀ = 5–1500 mg L⁻¹), and at 20 °C. Activated biochars presented higher phenol adsorption capacity compared to biochars due to their improved textural properties, higher micropore volume, and proportion of oxygenated carbonyl groups connected to their surface. The sorption equilibrium was reached within less than 4 h for all of materials, while the Langmuir model best described their sorption process. The maximum sorption capacity of activated biochars for phenol was found to be twofold relative to biochars (303 vs. 159 mg g⁻¹). Results also showed that activated biochars were more effective than biochars in removing low phenol concentrations in real effluents. In addition, 95% of phenol removal was attained within 96 h (although 85% was removed after 4 h), thus reaching below the maximum authorized concentration allowed by Québec’s discharge criteria (0.05 mg L⁻¹). These results show that activated biochars made from wood residues are promising potential adsorbent materials for the efficient treatment of phenol in synthetic and real effluents.