Side issues of economy development break out in China during recent decades, like environmental pollution or the widely ignored one, shadow economy. Using annual data for the three provinces at northeast China over the period 2000 to 2016, this paper examines the size of the shadow economy by MIMIC model first and then adopts the dynamic panel analysis to study the direct relationship between the shadow economy and pollution level. The major innovation point of this paper is the pioneering study of the impact from the pollution level on the size of shadow economy. We also employ various pollution descriptions from terrestrial, aquatic, and atmospheric ecosystems as the robustness check to make our following conclusions more comprehensive and credible: (1) shadow economy is a direct quality factor to the increase of the pollution level. (2) A positive effect from pollution to shadow economy also exists: the higher the pollution level is, the larger the size of shadow economy will be. In the end, this paper proposes several valuable information and suggestions to the government in economy development and pollution abatement.

Contamination by potentially toxic elements (PTEs) in children’s toys and jewelry is an ongoing problem, and there is evidence in the literature that the issue is shifting towards developing countries and small markets. The present research aims (1) to characterize total concentrations of eleven PTEs (As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn) in children’s jewelry and toys purchased from the Central Asian market (n = 65), and (2) to investigate the relationship between the extent of contamination and sample categories/properties. The laboratory analyses showed that the majority of the samples had PTEs above the total and soluble limits for PTEs stated in the USA, Canadian, and the EU legislation. Particularly for metallic toys and jewelry (n = 46), the total concentrations in 45 samples exceeded the EU migration limits for one or more PTEs. In particular, Cu and Zn concentrations were extremely high (up to 100%) in many samples and highly toxic Cd and Pb were present in elevated quantities in several articles. Contamination was also present, albeit to a much lesser extent, in other toy categories: brittle/pliable toys for Co and Cr, plastic toys and jewelry for Pb, and other toys for Co. Although average values and visual observations suggested evidence, no statistically significant relationship between PTE concentrations and sample properties (color, price, and degree of appeal) could be found. The findings supported the evidence that the contamination issue in children’s jewelry and toys by PTEs is an ongoing issue in developing countries. Very high total concentrations of PTEs particularly found in several metallic samples warrant further investigation of migratable concentrations. Thus, conducting bioaccessibility tests and a subsequent human health risk characterization is recommended. Overall, there is a potential risk for children in the case of exposure to PTEs from children’s jewelry and toys sold on the Central Asian market. More effective enforcement of legislation for consumer goods in the region and raising public awareness regarding chemicals in children’s products are recommended.

This study evaluates the inhibitory effect of a yeast strain, Aureobasidium pullulans KKUY0701, isolated from decayed cyanobacterial bloom against harmful cyanobacterium Microcystis aeruginosa and determines the ability of this strain to remove microcystin (MC) toxin from the water. The antialgal activity of this yeast strain was assayed by co-cultivation with M. aeruginosa, diatom, and green algal species. The MC adsorption experiment was conducted in the presence of living and heat-inactivated yeast cells. Both yeast cells and filtrates caused a rapid reduction in the growth of M. aeruginosa, with complete death and cell lysis occurring after 3 days. The yeast strain did not exhibit any inhibitory effect on either green algae or diatoms. Both living and heat-inactivated yeast cells were capable of adsorption of MC on their surfaces. Inactivated yeast exhibited higher adsorption capacity and lower intensity than living yeast for the adsorption of MC toxin. The results of this study suggest that this yeast strain could be employed to selectively reduce cyanobacterial blooms in freshwaters. Moreover, the application of heat-inactivated yeast’s biomass for toxin adsorption gives new possibilities in drinking water treatment plants.

Reduction of mercury emission from coal combustion is a serious task for public health and environmental societies. Herein, Ce-doped TiO₂ (Ce/TiO₂) catalyst coupling with a novel optical fiber monolith reactor was applied to efficiently remove elemental mercury (Hg⁰) from coal-fired flue gas. Under the optimal operation condition (i.e., 1.5 mW/cm² UV light, 90 °C), above 95% of Hg⁰ removal efficiency was attained over the optical fiber monolith reactor coating with 3.40 g/m² Ce/TiO₂ catalyst. The effects of flue gas compositions on Hg⁰ removal performance were clarified systematically. Gaseous O₂ replenished the surface oxygen, hence maintaining the production of free radicals and promoting the removal of Hg⁰. SO₂, HCl, and NO inhibited Hg⁰ removal in the absence of O₂ due to the competitive adsorption and consumption of free radicals. However, SO₂ and HCl significantly enhanced Hg⁰ removal with the participation of O₂, while NO exhibited obviously inhibitory effect even with the assistance of O₂. H₂O also decreased the Hg⁰ oxidation capacity owing to the competitive adsorption and reduction of HgO. The optical fiber monolith reactor exhibited much superior Hg⁰ removal capacity than the powder reactor. Utilization of Ce/TiO₂ catalyst coupling with an optical fiber monolith reactor provides a cost-effective method for removing Hg⁰ from coal-fired flue gas.

Fluoride is widely distributed in the environment and has been associated with the development of different health hazards in animals and humans. Argan oil (AO) is a natural vegetable oil with various beneficial pharmacological effects. This study was designed to investigate the potential protective effect of AO supplementation as pre-treatment or co-treatment on sodium fluoride (NaF)–induced nephrotoxicity in rats. Male Sprague Dawley rats (n = 50) were randomly assigned to one of five equal groups: control group, AO-treated group (6 ml/kg b.wt.), NaF-treated group (20 mg/kg b.wt.), pre-treated group, and co-treated group. All rats were daily administered by oral gavage for duration of 30 days. The results showed that AO administration significantly improved renal function and antioxidant status and decreased the lipid peroxidation in NaF-treated rats. Additionally, AO normalized the renal levels of inflammatory markers and mRNA expression level of the intermediate filament protein genes, indicating NaF-induced podocyte damage was ameliorated. Histopathological evaluation of the kidney confirmed the before mentioned biochemical results. AO counteracted the nephrotoxic effects of NaF in rats particularly at co-exposure. These results concluded that AO administration exhibited a significant nephroprotective effect against renal injury induced by NaF in rats.

Surfactants represent a billionaire market of amphiphilic molecules with worldwide applications in almost every branch of modern industry. The most common surfactants, available and currently used, are chemically produced. However, there is an urge to replace these chemical compounds with those obtained by mild and green technologies such as microbial biosurfactants produced by fermentative processes. Rhamnolipids are glycolipid biosurfactants that present highly effective surface-active properties and enormous market potential; nevertheless, their production costs remain not competitive. Here, we present a process of rhamnolipid production by static submerged cultivation using membranes of bacterial cellulose as substrate. The mixture of the rhamnolipid congeners was characterized showing effective surface-active properties and high amount of di-rhamnolipids (95.6%). Through this fermentative technology, 15.8 g/L of rhamnolipid was reach using a very simple and low-cost medium. The present process might decrease biosurfactant production cost, avoid foam formation, and finally make rhamnolipid production more viable.

The present study proposes the synthesis and characterization of graphene oxide (GO) and its application in the adsorption of the antibiotic cephalexin (CFX) in aqueous solution. The characterization of graphene oxide was obtained by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential. The influence of pH on the batch adsorption process was investigated by analysing adsorption equilibrium isotherms and adsorption kinetics. The images obtained by SEM and TEM presented the typical morphology attributed to GO sheets. The kinetic adsorption tests showed that equilibrium was reached in 420 min, and an adsorption capacity of 164 mg g⁻¹ was obtained. The models that best fit the experimental data were pseudo-second as well as the Langmuir isotherm. Therefore, GO was effective for removing the CFX antibiotic from aqueous solution by using a batch adsorption process.

In this paper, a simple hydrothermal method is employed to synthesize BiSI/BiOI/CNT nanocomposite with enhanced photocatalytic activity. The properties of the prepared samples were studied using nitrogen adsorption-desorption isotherm, photoluminescence, X-ray diffraction analysis (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), UV–vis diffuse reflectance spectroscopy (DRS), and electrochemical impedance spectroscopy (EIS). The loading amount of CNT had a significant influence on the photoactivity of the BiSI/BiOI/CNT composite. In this study, several BiSI/BiOI/CNT nanocomposite samples with various mass ratios of CNT were made-up for further investigation to scrutinize the influence of CNT content on the photocatalytic activity of the nanocomposite. Photocatalysis measurements revealed that 2% Wt of CNT possesses the highest photocatalytic activity in the visible light irradiation with 93.1% photodegradation of malachite green (MG) as a test dye. The enhanced photocatalytic performance can be due to the large surface area, excellent conductivity performance, and high absorption ability in the visible light region. The synergistic effect of the factors mentioned above makes BiSI/BiOI/CNT nanocomposite a high-performance photocatalyst under visible light irradiation. An appropriate reaction mechanism of dye photodegradation has suggested according to the result of active species trapping experiments.

Due to the effects of Hurricane Patricia (2015), the bulk freighter “El Llanitos” ran aground in the rocky intertidal zone of Colima, Mexico. We assessed the impact of this ship’s stranding on a population of the gastropod Plicopurpura pansa. Toxic elements, hydrocarbons, shell deformities, presence of tumors, imposex, and morphological relationships were analyzed. Two years after the stranding occurred, high cyanide concentrations (0.0363 mg/l) and Ni concentrations above permissible limits (3.35 mg/l) were found in surface seawater. Hydrocarbon concentrations were high in the aft zone of the ship and decreased towards the bow area of the freighter. The P. pansa specimens collected closest to the ship structure presented a high prevalence of tumorations in the structure of the foot and morphological anomalies in the shell structure; imposex was 32% and there was evidence of effects on the growth indicator. The evidence presented here supports the existence of a significant impact from the grounding of the ship on a protected gastropod species associated with the rocky intertidal zone on the coast of Colima. The potential of P. pansa as a bioindicator species of pollution caused by toxic elements and hydrocarbons associated with stranding events in the tropical Pacific is documented.

The effect of climate warming on soil organic carbon (SOC) of sediment in wetlands is important for accurately projecting SOC content. Thus, understanding the mechanism influencing SOC content under climate warming is necessary. Field investigation and a laboratory incubation experiment were conducted in Hulunbeier steppe wetland during 2016 and 2017. Four types of wetland were selected to incubate with ambient temperature and temperature increased by 2.5 °C. The results showed that SOC content was negatively affected by temperature warming. The SOC content reduction in sediment caused by increasing temperature was ranged from − 2.34 to 39.52%. In addition, the content of sand, silt, total phosphorus (TP), calcium phosphate tribasic (Ca-P), total nitrogen (TN), and sediment moisture (MC) should be considered in models of SOC content in steppe wetland. However, it requires further validation, in particular how SOC content varies with warming temperatures, the duration of incubation, and other abiotic and biotic factors. These findings provide evidence that both climate warming and original characteristics of sediment can control the SOC storage dynamics in the steppe wetland. Graphical abstract