This study examines the effect of financial development (FD) and foreign direct investment (FDI) on the environmental quality for the panel of 90 belt and road countries from 1990 to 2017. This study advances the knowledge of financial development by using the new comprehensive index, which is based on access, depth, and efficiency of financial markets and financial institutions and incorporated foreign direct investment as an important determinant of environmental quality. By applying the Driscoll-Kraay standard error pooled ordinary least square method, the empirical findings reveal that FD deteriorates the environmental quality by increasing the CO₂ emissions, while FDI improves environmental quality and the relationship between economic growth (EG) and CO₂ emissions is inverted U-shaped, i.e., presence of EKC hypothesis. The energy consumption and urbanization pollute the environment, while trade openness enhances the quality of the environment. Furthermore, the Dumitrescu-Hurlin (DH) panel causality test result confirms that the bidirectional causality exists among FD, trade openness, energy consumption, and urbanization with CO₂ emissions. The empirical results provide new insights for policymakers and also have several implications for the betterment of environmental quality.

The paper represents a scientometric analysis of a documentary array selected form Web of Science database on the issue “Oil and petroleum products in soil and groundwater.” The analysis of the array shows its positive dynamics since the mid-1990s and especially active growth recently; names of the countries and organizations most actively working on the aforementioned problem; authors leading by the number of publications; periodicals and serial publications with high publication activity; scientific meetings that discussed the problems of soils and groundwater contamination by oil and oil products; and the most cited publications. The authors carry out visualization of the scientific field “Oil and petroleum products in soil and groundwater” using CiteSpace software. Documents co-citation analysis with the CiteSpace revealed main research fronts: biotransformation, biodegradation of oil and oil products in the studied media, bioremediation of these media, new research trend related to unconventional methods of oil production. The CiteSpace also lets to identify within the document co-citation network prominent cited publications (according co-citation frequency, betweenness centrality, and the strength of citation bursts). The most prominent research direction—bioremediation—is identified.

This study investigates the performance of a sequential pyrite-Fenton and biological process for the treatment of 2-chlorophenol (2-CP) containing wastewater using pyrite-Fenton process as a pretreatment stage. Pyrite was tested as a catalyst material in Fenton reaction due to its low cost and high abundance in the environment. All experiments were run in batch mode. The biodegradation experiments were performed under aerobic conditions using glucose as the co-substrate with untreated or Fenton-pretreated 2-CP. Despite the 100% removal of 2-CP in batch pyrite-Fenton reactors, the total organic carbon (TOC) removal only approached 70%, implying the transformation of 2-CP into some chemically stable intermediate reaction by products during pyrite-Fenton oxidation. In systems with no pyrite-Fenton pretreatment, a combined effect of biotic and abiotic processes including biological degradation, sorption, and volatilization played a significant role on 2-CP removal. The pyrite-Fenton pretreatment of 2-CP significantly improved the performance of aerobic biological reactor relative to system with no pyrite-Fenton pretreatment by (1) reducing the toxicity of 2-CP on aerobic microbial cells and (2) enhancing cell growth. Overall, this study shows that pyrite-Fenton pretreatment coupled with aerobic biological degradation could provide a cost-effective solution for the treatment of wastewater containing low-biodegradable toxic compounds such as chlorophenols.

The levels of persistent organic pollutants, polychlorinated biphenyls (PCBs), were investigated in influent, effluent, and sludge of five wastewater treatment plants (WWTPs) in Jordan. Concentrations of 12 dioxin-like PCBs were determined. The extraction of PCBs from wastewater samples was done by solvent extraction using dichloromethane/hexane 1:1 mixture. The concentrated extracts were sequentially subjected to multilayer silica gel, basic alumina, and florisil chromatography columns for further cleanup. Sludge samples were extracted in a Soxhlet apparatus, using petroleum ether. PCB determination has been completed using gas chromatography equipped with mass spectrometry detector. The total concentrations of PCBs in influent samples ranged from 34.65 to 228.3 ng L⁻¹, in effluent samples from 16.1 to 123.88 ng L⁻¹, and in the sludge samples from 51.1 to 223.85 ng kg⁻¹. In three of the investigated wastewater treatment plants, the amount of PCBs in sludge exceeded the limit proposed by European Union legislation. The total removal efficiencies of the total PCBs were evaluated and ranged from 34.8 to 88.1% for Aqaba and Abu-Nsair WWTP, respectively. The values of incremental lifetime cancer risk due to exposure to PCBs in sludge samples were also estimated in this study, and they ranged from 2.415 × 10⁻⁷ to 1.193 × 10⁻⁶ for adults. The number of people suspected to have cancer due to the exposure to the sludge of the WWTPs in Jordan is between 4 and 20 out of ten million.

With the development of the boron industry, boron pollution is getting more and more serious, and excessive boron will harm human health. In this paper, graphene oxide was used as a template to prepare ZIF-67, and GO/ZIF-67 was successfully prepared. GO/ZIF-67 was used for the first time to remove boron from water. SEM, XRD, and other characterization methods were used to confirm the structure. The adsorption kinetics, adsorption isotherm, adsorption thermodynamics, and adsorption mechanism of boron by GO/ZIF-67 were studied in this paper. The adsorption capacity of GO/ZIF-67 for boron is up to 66.65 mg·g⁻¹ at 25 °C, and adsorption process reaches equilibrium in 400 min. Adsorption kinetics indicates that the adsorption process conforms to the pseudo-first-order kinetic model, and adsorption thermodynamics indicates that the adsorption process is a spontaneous endothermic process controlled by entropy change. The adsorption capacity of boron by GO/ZIF-67 does not decrease significantly after four cycles. The adsorption of boron by GO/ZIF-67 has both chemical and physical adsorption. From Zeta potential and adsorption kinetics, it can be seen that there is physical adsorption during the adsorption process and boron mainly has positive charge on the surface of GO/ZIF-67 and graphene oxide hydroxyl bonding. Based on the adsorption thermodynamics and XPS, it is known that there is chemisorption during the adsorption process, and mainly the combination of boron and cobalt sites.

The Cipeles watershed is the largest subsystem of the Cimanuk watershed, which is located in an agricultural area. Some segments of the Cipeles River are appropriate for aquatic life habitat. To assess the pollutant risk from heavy metals, which tend to accumulate in the environment, this study determined the heavy metal concentrations as a basic database, calculate the heavy metal pollution index (HMPI), and assess the correlation between heavy metals from the surface and pore waters of Cipeles River. Samples from 11 sampling stations at the end of the wet season were collected, preserved, and characterized using inductively coupled plasma mass spectrometry. The heavy metal concentrations were then plotted on a map using a geographic information system. As a result, the heavy metal occurrence in pore water was found to be Mn > Fe > Ba > Co > Zn > Cu > Pb > Cr in the order of abundance, while the order was slightly different in surface water, i.e., Fe > Mn > Zn > Ba > Cu > Pb > Co > Cr. Both pore and surface waters showed similar dominance for iron and manganese, where they mostly originated from the run-off water from the laterite and alluvial soils at the sampling locations. The other micro-concentrations of heavy metals indicate the anthropogenic source of pollutants. The HMPI indicated a low level in the upstream area, medium to high levels in the city center, and high levels in the downstream area. Moreover, there is a significant correlation between the heavy metal concentration at pore and surface waters, especially for Mn and Co in the city area and also Zn and Ba in the downstream area.

One of the most industrially affected rivers in Taiwan, the Houjing River, was studied in this research. The water and sediment samples were collected at five locations to measure the concentration of eight metals (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn). In order to assess the heavy metal contamination and its adverse biological effect, the heavy metal pollution index (HPI), the degree of contamination index (DC), the contamination factor (CF), the index of geo-accumulation (Igₑₒ), and hazard quotients (HQs) were employed. The results showed that the Houjing River’s water and sediment were contaminated with heavy metals. The annually averaged values of HPI (128.3) and DC (21.3) indicate that the water is unsafe for potable use and the sediment contamination level is at considerable degree of contamination. CF and Igₑₒ calculation show that Zn, Cu, and Cd are the three main metals contributing to heavy metal contamination in sediment. Evaluation of adverse biological effects suggests that Zn, Cu, and Ni are the major metals that cause adverse effects on organisms. This study provides an overview of the synergistic heavy metal contamination degree of the Houjing River and its adverse biological effects, which should be a reliable reference for future contamination control and management plans.

Humic acids (HA) are natural substances which exhibit a remarkable spectrum of health benefits, such as their role in chelation. This study aims to supplement the current knowledge on the chelating effects of HA in chronic lead intoxication in rat femurs and in liver, heart and kidney mitochondria in an experiment lasting 10 weeks. Lead acetate trihydrate was administered to rats for 5 weeks at a daily dose of 155.5 mg/kg body weight. At the same time, rats were given three concentrations of HA, with their effect measured over the following 5 weeks. Increased Pb concentrations were detected in the femur after the first week, while HA-administered groups showed a tendency towards inhibiting the increase in Pb deposition. After 5 weeks, Pb concentrations dropped significantly in the HA groups. At the same time, however, other elements were redistributed, with a decrease in Se and Zn being particularly noteworthy. While an increase in Pb concentrations was found after 5 weeks of Pb administration, a concentration of 1% HA resulted in the least significant increase in Pb as well as an increase/decrease in Se/Cu, respectively. In mitochondria, an increase in Pb content was detected after the first and fifth weeks with concomitant redistribution of other elements. At the end of the experiment, again in the 1% HA group, Pb concentrations remained higher only in the liver with the other elements sufficiently normalized, indicating this concentration to be useful in the treatment of Pb intoxication.

Bisphenol A (BPA) received heightened attention in the recent years due to humans continuously being exposed to it. This study explores the effect of taurine or curcumin on subacute BPA treatment-induced nephrotoxicity in rats (Rattus norvegicus). Forty-two adult albino male rats were exposed to BPA (130 mg/kg daily) for 28 days by gastric gavage. BPA led to lipid peroxidation, inhibiting antioxidant enzyme activities like catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST). BPA exposure also induced histopathological changes like tubular and glomerular degeneration, vascular congestion, and interstitial cell infiltration in kidney tissue. Cotreatment with taurine (100 mg/kg daily) or curcumin (100 mg/kg daily) alleviated the lipid peroxidation level and antioxidant enzyme activities and histological alterations brought about by BPA. In this study, curcumin and taurine application provided protection against renal toxicity caused by BPA but did not prevent toxic effect completely.

Sugarcane vinasse, also known as distillery wastewater, is a key by-product of the ethanol industry. Vinasse characteristics and their huge volume pose environmental concerns about the choice of treatment method. Microfiltration (MF) has been efficiently applied to vinasse clarification; however, it has been underexplored in the literature. In this context, the present study investigated the application of coagulation and cross-flow MF for vinasse clarification. To maximize the process efficiency, operational parameters were optimized using the one-factor-at-a-time method in batch tests. The optimal values were Superfloc C492 concentration of 5 mg L⁻¹, backpulsing frequency of 10 min, and vinasse temperature of 45 °C, which showed a removal of 35.0, 86.0, and 99.9% for chemical oxygen demand (COD), color, and turbidity, respectively. The optimization process significantly improved the vinasse flux but did not show any influence in the permeate quality. Optimal parameters were successfully applied to the continuous mode in the MF system, which operated during 164 h at an average flux of 21.6 L h⁻¹ m⁻². High removals were reached for color (79.3%) and turbidity (99.6%), and low removal was found for COD (31.6%), which are in agreement with the batch mode tests. This work showed the importance of operational optimization, and the results provide valuable support for establishing practical guidelines for vinasse clarification in the ethanol industry. Graphical Abstract