With increasing concern related to sustainable chemistry, we investigated the biosorption of Pb²⁺ ions from aqueous medium using an environmental friendly and economic biosorbent Bougainvillea spectabilis (BS). The BS was modified effectively using citric acid by hydrothermal method. The biosorbent(s) was characterized by scanning electron microscope (SEM), energy dispersion X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and point of zero charge (pHₚzc). Various process parameters including biosorbent dosage, time of contact, temperature, solution pH, and initial Pb²⁺ ions concentration were studied in batch mode. Kinetic modeling was performed to evaluate the kinetic data and results showed that the studied process followed the pseudo second order (PSO) kinetics. Equilibrium modeling was done using famous equilibrium models, i.e., Langmuir, Freundlich, Dubinin-Kaganer-Radushkevish, and Temkin in non-linear fashion to evaluate equilibrium data by varying initial Pb²⁺ ions concentration from 20 to 180 mg/L. Based on RMSE values, Langmuir model fits best. This paper also discusses thermodynamic parameters (i.e., enthalpy, entropy, and free energy) showing that the process was spontaneous and endothermic in nature. In comparison with BS (B. spectabilis), an appreciable increase in uptake capacity of CABS (citric acid modified B. spectabilis) was observed in sequestration of Pb²⁺ ions from aqueous medium showing advantage of citric acid modification making it industrially favorable and socially acceptable biosorbent for efficient removal of lead from water.

Deca-bromodiphenyl ether (BDE-209) regulates various aspects of spermatogenesis and male fertility through its effect on estrogen receptor α (ERα), but the underlying mechanism remains unclear. Because molecular mechanisms such as remodeling of the blood-testis barrier (BTB) play crucial roles in spermatogenesis, we investigated the disruptive effects of ERα agonists on the BTB in spermatogenesis. In this study, 0, 300, and 500 mg/kg/day of BDE-209 were administered to pregnant adult mice by oral gavage from gestation day 7 to postnatal day 21. SerW3 cells were treated with methylpiperidino pyrazole (MPP) for 30 min before being treated with 50 μg/mL of BDE-209. BDE-209 increases ERα in time- and dose-dependent manners and decreases formin 1 and BTB-associated protein in F1 male mice. Furthermore, BDE-209 impairs the structure and function of the BTB. Activation of ERα signaling could disrupt the BTB, leading to spermatogenesis dysfunction. The results identified the role of ERα in BTB disruption during spermatogenesis and suggested that BTB disruption occurs because of exposure to BDE-209, which could potentially affect spermatogenesis. In conclusion, Sertoli cells seem to be the primary target of BDE-209 in the perinatal period, and this period constitutes a critical window of susceptibility to BDE-209. Also, the SerW3 cell model may not be a particularly useful cell model for studying the function of the cytoskeleton.

Many recent studies have focused on the influencing factors of the ecological footprint, but less attention has been given to human capital. Human capital, which is based on education and rate of return on education, may reduce the ecological footprint since environmental issues are human-induced. The current study investigates the impact of human capital on the ecological footprint in India for the period 1971 to 2014. The outcomes of the newly developed combined cointegration test of Bayer and Hanck disclose the long-run equilibrium relationship between variables. The findings reveal a significant negative contribution of human capital to the ecological footprint. The results of the causality test show that human capital Granger causes the ecological footprint without any feedback. In addition, energy consumption adds to the ecological footprint, while the relationship between economic growth and ecological footprint follows an inverted U-shaped pattern. The findings unveil the potential to reduce the ecological footprint by developing human capital.

Denitrifying bioelectrochemical system provided an alternative technology for nitrogen removal, even power recovery from wastewater, and its nitrogen removal performance and intermediate accumulation were affected by the extracellular electron transfer modes and rate-limiting steps in denitrifying biocathodes. In the current study, the extracellular electron transfer modes and rate-limiting steps for nitrate reduction and nitrite reduction of denitrifying biocathode were investigated through cyclic voltammetry. When the cathode potential swept from 0.003 to − 0.897 V (vs. Ag/AgCl), denitrifiers were indispensable for electrochemical denitrification. Three peak potentials were found in the cyclic voltammogram of denitrifying biocathode, where E₁ (− 0.471 to − 0.465 V) and E₂ (− 0.412 to − 0.428 V) represented respectively nitrate reduction and nitrite oxidation while E₃ (− 0.822 to − 0.826 V) represented nitrite reduction. Nitrate reduction involved the direct electron transfer mode while nitrite reduction involved the mediated electron transfer mode. Intracellular catalytic reaction was the rate-limiting step for nitrate reduction, independent on the electrochemical activity of denitrifying biocathode and the nitrate supply. The nitrate supply posed an effect on the rate-limiting step for nitrite reduction. The mediator transfer was the rate-limiting step for nitrite reduction in the absence of nitrate. But both mediator transfer and intracellular catalytic reaction became the rate-limiting steps for nitrite reduction in the presence of sufficient nitrate.

1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBP-TAZTO) is an emerging brominated flame retardant which is widely used in several plastic materials (electric and electronic equipment, musical instruments, automotive components). However, until today, no photochemical studies as well as the identification of possible phototransformation products (PTPs) were described in literature. Therefore, in this study, UV-(C) and simulated sunlight irradiation experiments were performed to investigate the photolytic degradation of TDBP-TAZTO and to identify relevant PTPs for the first time. The UV-(C) irradiation experiments show that the photolysis reaction follows a first-order kinetic model. Based on this, the photolysis rate constant k as well as the half-life time t₁/₂ were calculated to be k = (41 ± 5 × 10⁻³) min⁻¹ and t₁/₂ = (17 ± 2) min. In comparison, a minor degradation of TDBP-TAZTO and no formed phototransformation products were obtained under simulated sunlight. In order to clarify the photochemical behavior, different chemicals were added to investigate the influence on indirect photolysis: (i) H₂O₂ for generation of hydroxyl radicals and (ii) two quenchers (2-propanol, sodium azide) for scavenging oxygen species which were formed during the irradiation experiments. Herein, nine previously unknown PTPs of TDBP-TAZTO were detected under UV-(C) irradiation and identified by HPLC-(HR)MS. As a result, debromination, hydroxylation, and dehydrobromination reactions could be presumed as the main degradation pathways by high-resolution mass spectrometry. The direct as well as the OH radical-induced indirect photolysis were observed. Graphical abstract .

Exposure to complex organic substances present in textile wastewater has been considered a threat to human health and aquatic organisms. Development of appropriate treatment mechanisms, as well as sensitive monitoring assays, is considered important in order to safeguard and protect the delicate natural equilibrium in the environment. In this study, combined coagulation/flocculation and electrohydraulic discharge (EHD) system were explored for treatment of textile wastewater. Pre- and post-treatment samples were used to evaluate process efficiencies. Process efficiencies were evaluated using physicochemical characteristics, and cytotoxicity and inflammatory activities induced in macrophage RAW264.7 cell line. The RAW264.7 cell line was evaluated as an alternative to animals and human blood culture models, whose routine applications are hindered by stern ethical requirements. The toxicity of effluent was evaluated using WST-1 assay. The inflammatory activities were evaluated in RAW264.7 cell culture supernatant using nitric oxide (NO) and interleukin 6 (IL-6) as biomarkers of inflammation. The levels of NO and IL-6 were determined using the Griess reaction assay and double-antibody sandwich enzyme-linked immunoassay (DAS ELISA), respectively. Overall, the results of this study show that combined approaches and not the single EHD system are sufficient for complete removal of chemical oxygen demand (COD) and total organic carbon (TOC), toxicity and inflammatory activities in textile wastewater. The study shows that induction of NO and IL-6 secretions in macrophage RAW264.7 cells is a very sensitive model system to monitor the efficiency of textile effluent treatment processes.

Indirect potable reuse systems, which consist of wastewater treatment (WWT) and soil aquifer treatment (SAT), offer advantages such as their low cost and the underground storage of reuse water. In this study, the dissolved organic matter (DOM) profile of a sequential treatment system (i.e. WWT followed by SAT) was investigated using a pilot-scale SAT reactor. In addition, the biological DOM removal characteristics in the vadose zone of the SAT, which were found to play an important role in DOM removal for the entire SAT, were investigated using lab-scale reactors (LSRs). Composition of the removed DOM by WWT and SAT showed that the majority fraction of the removed DOM was different for the WWT (hydrophobic neutral 27.9%) and SAT (hydrophobic acids (HoA) 29.1%), suggesting that SAT exhibits unique DOM removal characteristics that contribute to water reclamation. Biological DOM removal was confirmed using the LSRs, and changes in the DOM removal characteristics 10–20 cm from the top of the vadose zone in the LSRs were revealed on the basis of the DOM fractionation and a BIOLOG assay, suggesting that microbial activity in the lower layer of the vadose zone contributed to the unique removal of the HoA fraction in the SAT.

Production, distribution, and disposal of pharmaceutical products, including beta-blockers, have become a global issue. Beta-blockers are known to persist in the environment months after their release and may result in the disruption of the homeostatic system in non-target organisms. Here, we study the bioconcentration of three of the most commonly used beta-blockers and their effect on the regeneration of Girardia dorotocephala, a freshwater brown planarian. Acute toxicity tests determined LC₅₀s for acebutolol, metoprolol, and propranolol to be 778 mg/L, 711 mg/L, and 111 mg/L, respectively. The quantification and analysis of beta-blocker bioconcentration during acute exposure were performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After 4 days of exposure to beta-blockers, the bioconcentration drastically decreased for all three beta-blockers at all exposure levels, suggesting that an effective mechanism to reduce uptake or excrete beta-blockers could be present. Additionally, Girardia dorotocephala were cut proximal to the head and the quality of regeneration was documented from each fragment daily. No significant difference was visually observed after 2 weeks of regeneration between the brown planarians placed in beta-blocker solution and those placed in control solution.

Traditional medicine (TM) including Ayurvedic medicines, traditional Chinese medicines and nutraceuticals are popular across the globe as dietary supplements and traditional and alternative medicines. Health risks from these remedies continue to present serious concerns, with occurrences of poisoning by metals and metalloids present at concentrations above acceptable regulatory standards. This review overviews the prevalence of TM use, cases of metal and metalloid poisoning following TM consumption, and forms of TM contamination and adulteration. The review summarises regulations by the World Health Organization (WHO) and other relevant bodies. Finally, the review recommends how to protect consumers.

Currently, the urgency of balancing rice production and environmental risk from nitrogen (N) fertilization is gaining scientific and public attention. As such, a field experiment was conducted to investigate the rice yield and the fate of applied-¹⁵N for Yangliangyou 6 (a two-line hybrid cultivar) and Lvdaoq 7 (an inbred cultivar) using 10 combinations of N rates and splitting ratios in the middle reaches of the Yangtze River. The results showed that N application primarily affected fertilizer N loss to the environment, followed by plant N absorption, but had little effect on grain yield. Generally, there was no significant increase in grain yield and N accumulation in the aboveground plant when N inputs surpassed 130 or 170 kg ha⁻¹. Fertilizer N residue in soil peaked at approximately 48 kg ha⁻¹ at an N rate of 170 kg ha⁻¹ for both varieties; however, a sharp increase of fertilizer N loss occurred with further incrementally increasing N rates. Although a higher ratio of panicle-N fertilizer together with a lower ratio of tillering-N fertilizer at rates of 130, 170, and 210 kg ha⁻¹ had no grain yield benefit, it promoted aboveground N accumulation and plant N accumulation derived from fertilizer, and it reduced the amount of N residue in soil and N loss to the environment. Overall, reducing tillering-N ratios and increasing panicle-N ratios at an N rate between 130 and 170 kg ha⁻¹ using fertilizer rates of 90–0–40 kg ha⁻¹ and 90–40–40 kg ha⁻¹ N at basal-tillering-panicle initiation stages could reduce the adverse environmental risks of chemical N from rice production without sacrificing rice yield.