Pollution of environmental endocrine disruptors has caused increasing concern globally. In the current study, a simple colorimetric method with high sensitivity and good selectivity for 17β-estradiol (E2) detection was developed, which employed gold nanoparticles (AuNPs) as colorimetric probe for specific recognition of shortening DNA aptamer. Visible color change from bright red to violet was observed for aggregation of AuNPs without the protection of DNA aptamer. After optimization, the method exhibited great performance for E2 detection with good linearity between E2 concentrations from 0.2 to 5 nM and the absorbance ratio at 620 and 523 nm, with the limit of detection of 0.1 nM. The method was also successfully applied to E2 determination in different spiked water samples including fishpond water, lake water, and tap water, in which good recoveries from 93.1 to 108.9% and acceptable relative standard deviations from 3.4 to 8.9% were obtained. This technique showed great potential for on-site fast determination of E2 in environmental water samples.

Cadmium and mercury are non-biodegradable toxic metals that may cause many detrimental effects to the thyroid gland and blood. Vitamin C has been found to be a significant chain-breaking antioxidant and enzyme co-factor against metal toxicity and thus make them less available for animals. The current study was performed to find the effect of individual metals (cadmium and mercury), their co-administration, and the ameliorative effects of vitamin C on some of the parameters that indicate oxidative stress and thyroid dysfunction. Cadmium chloride (1.5 mg/kg), mercuric chloride (1.2 mg/kg), and vitamin C (150 mg/kg of body weight) were orally administered to eight treatment groups of the rabbits (1. control; 2. Vit C; 3. CdCl₂; 4. HgCl₂; 5. Vit C + CdCl₂; 6. Vit C + HgCl₂; 7. CdCl₂ + HgCl₂, and 8. Vit C + CdCl₂ + HgCl₂). After the biometric measurements of all experimental rabbits, biochemical parameters viz. triidothyronine (T₃), thyroxine (T₄), thyroid-stimulating hormone (TSH), and triglycerides were measured using commercially available kits. The results exhibited significant decline (p < 0.05) in mean hemoglobin, corpuscular hemoglobin, packed cell volume, T₃ (0.4 ± 0.0 ng/ml), and T₄ (26.3 ± 1.6 ng/ml) concentration. While, TSH (0.23 ± 0.01 nmol/l) and triglyceride (4.42 ± 0.18 nmol/l) were significantly (p < 0.05) increased but chemo-treatment with Vit C reduces the effects of Cd, Hg, and their co-administration but not regained the values similar to those of controls. This indicates that Vit C had a shielding effect on the possible metal toxicity. The Cd and Hg also found to accumulate in vital organs when measured by atomic absorption spectrophotometer. The metal concentration trend was observed as follows: kidney > liver > heart > lungs. It was concluded that Cd and Hg are toxic and tended to bioaccumulate in different organs and their toxic action can be subdued by vitamin C in biological systems.

In this study, the cellulose nanocrystals (CNC) obtained by acid hydrolysis of microcrystalline cellulose (MCC) are customized by suspension to obtain a spherical CNC hydrogel. The N-(2-aminoethyl) (3-amino-propyl) methyldimethoxyansile (AEAPMDS) preparation was grafted to spherical CNC hydrogel using a water phase heat treatment. Finally, aerogel samples were obtained by tert-butanol replacement and freeze-drying. The test results confirmed that the aminosilane was grafted on CNC. Electron micrographs and N₂ sorption isotherms showed that the pores of the aerogel were partially blocked due to the introduction of AEAPMDS, and the specific surface area was decreased. Due to the presence of chemisorption, the amount of CO₂ adsorbed at a pressure of 3 bar by the modified aerogel (2.63 mmol/g) was greatly improved compared with the unmodified aerogel (0.26 mmol/g), and the adsorption results were fit well by the Langmuir model. Thus, our experiments provided the opportunity to develop a new CO₂ absorbent material.

In this study, the synthesis of iron oxide stabilized by chitosan was carried out for the application and optimization in the removal process of aqueous Cr(VI) by central composite design (CCD). The calculation of these effects allowed to know, quantitatively, the variables and the interaction between them that could affect the Cr(VI) removal process. It was also verified that the most favorable conditions for chromium removal were the following: pH 5.0, Cr(VI) concentration of 130 mg L⁻¹, adsorbent mass of 5 mg, and Fe(II) content of 45% (w/w) in the CT-Fe beads. The adsorption kinetics performed under these conditions showed that the chitosan/iron hybrid composite is an adsorbent material with high chromium removal capacity (46.12 mg g⁻¹). It was found that all variables were statistically significant. However, it was observed that the variable that most affected Cr(VI) removal was the pH of the solution, followed by the concentration of chromium ions in solution and the interaction between them. Therefore, the studied experimental conditions are efficient in chromium adsorption, besides the operational simplicity coming from statistical design. Theoretical calculations showed that the most stable chitosan was that with Fe(II) in the structure, that is, in the reaction mechanism, there is no competition of Fe(II) with Cr(III, VI) in the available sites of chitosan. Thus, the theoretical calculations show that the proposed Cr(VI) removal is effective.

Steady efforts in using ultrasonic energy to treat oil-contaminated sand started in the early 2000s until today, although pilot studies on the area can be traced to even earlier dates. Owing to the unique characteristics of the acoustic means, the separation of oil from sand has been showing good results in laboratories. This review provides the compilation of researches and insights into the mechanism of separation thus far. Related topics in the areas of oil-contaminated sand characterizations, fundamental ultrasonic cleaning, and cavitation effects are also addressed. Nevertheless, many of the documented works are only at laboratory or pilot-scale level, and the comprehensive interaction between ultrasonic parameters towards cleaning efficiencies may not have been fully unveiled. Gaps and opportunities are also presented at the end of this article.

This study investigated the effects of residual ozone on the performance of microorganisms treating petrochemical wastewater using batch experiments with low and high ozone dosages (5.0 mg/L and 50.0 mg/L, respectively). The results indicated that the low residual ozone concentration significantly increased COD removal by 24.21% in the biological process compared to control group with no ozone residual, while the high residual ozone concentration showed the opposite effect. In the reactor with low residual ozone concentration (0.45 mg/L), the amount of loosely bound (LB)-extracellular polymeric substances (EPS) in the activated sludge decreased by 23.23%, while the amount of tightly bound (TB)-EPS increased by 129.16% compared to the none-ozone residual reactor. In addition, the low residual ozone was found to improve the bioactivity of activated sludge by 139.73% in the first 30 min of the biological process. In the reactor with high residual ozone concentration (0.91 mg/L), both LB- and TB-EPS of the activated sludge increased, while bioactivity decreased. This implies that low residual ozone in a bio-reactor can enhance microbial activity by increasing contact between the pollutants and cells by removing LB-EPS covering the outer layer of the sludge. The microorganisms in the sludge samples could be classified into three groups representing those that are susceptible to ozone, tolerant to low dose of residual ozone, and resistant to high dose of residual ozone. The resistant bacteria Gemmatimonadaceae uncultured became predominant, with a relative abundance of 11.37%, under low residual ozone conditions, while it decreased at high ozone concentrations. The results showed that a certain amount of residual ozone could stimulate the activity of microorganisms by altering the EPS fraction and structure of the microbial community, and thus it is important for the removal of refractory organics from wastewater in the ozone-biological process.

This study was carried out to reveal the people’s knowledge level about the harmful effects of waste oils, especially waste cooking oil, on the environment. It also aims to understand the attitude and behavioural patterns related to the safe disposal of them. Istanbul is chosen because it represents the entire country with its diverse socio-demographic and socio-cultural structure. A total of 408 respondents were randomly chosen and interviewed in the designated regions. The research data were obtained by using a structured survey consisting demographic and Likert scale questions. SPSS 23.0 statistical software was used to analyse the survey data. Results suggest that despite the high educational level, participants did not know that household liquid waste has a negative impact on the environment. They disagreed on the statement that liquid waste can damage water resources. Public spots, and formal and informal education were not found effective and failed to make the desired impact. Majority of participants did not know their duties in the disposal of waste. They also did not know where the liquid waste collection units were and what projects were being implemented in their neighbourhood. Fewer participants were concerned at what point and how the hazardous liquid wastes collected by municipalities were disposed of after leaving their habitat and whether these methods were reliable or acceptable. This research concludes that user behaviour was disappointing in cooking oil usage and waste oil disposal. The collection of waste cooking oils remains far below the developed countries.

The increasing scarcity of arable land necessitates the development of effective decontamination techniques to re-gain contaminated areas and make them suitable for agricultural and other activities. Herein, we prepare a ferromanganese binary oxide-biochar composite (FMBC) and compare its potential for remediating Cd-contaminated red soil with that of biochar (BC), showing that (i) the obtained adsorption data are well described by the Langmuir model and (ii) Cd adsorption capacity increases with increasing adsorbent dosage. Specifically, the Cd adsorption capacity of FMBC-amended soil (6.72 mg g⁻¹) is demonstrated to significantly exceed that of BC-amended red soil (4.85 mg g⁻¹) and that of the control (2.28 mg g⁻¹) and increases with increasing temperature and pH, while the results of instrumental analyses indicate that Cd sorption on the soil surface occurs via the formation of CdO and Cd(OH)₂. Thus, FMBCs are concluded to play an important role in the adsorption of Cd, having the potential to prevent red soil acidification and improve soil quality, and are found to be promising remediation materials for mitigating the risks posed by Cd-contaminated red soil.

The removal behavior and characteristic of cadmium (Cd²⁺) on wheat straw char activated by CO₂ were investigated in this study. The equilibrium, kinetics, and removal isotherms were studied. The results of batch experiments revealed that the removal of Cd²⁺ was described well by pseudo-second-order and Langmuir models. The increase in activation time improved the removal of Cd²⁺, especially for the activation time of 84 min. The results suggested that chemisorption of Cd²⁺ on activated carbon was the main reaction mechanism. The maximum removal capacity of Cd²⁺ onto activated WSC-84 was 75.55 mg/g, which was much higher than other three samples activated by CO₂ with other amounts of time. According to the results of SEM, XPS, and FT-IR, complexation with surface oxygen-containing functional groups, ion exchange, and precipitation were the possible mechanisms of the removal process. It is suggested that the experimental results will enhance the comprehensive understanding of the activation of biomass and its utilization in the restoration of Cd-contaminated soil.

Lung cancer as one of the major causes of cancer mortality has been demonstrated to be closely related to the ambient atmospheric environment, but little has been done in the synthetic evaluation of the linkage between cancer mortality and combined impact of ambient air pollution and meteorological conditions. The present study determined the environmental suitability for female lung cancer mortality associated with air contaminants and meteorological variables. A novel fuzzy matter–element method was applied to identify the spatial distribution and regions for the environmental suitability for the female lung cancer mortality across China in 2013. The membership functions between the cancer mortality and 6 environmental factors, including PM₂.₅, NO₂, SO₂, PM₁₀, the annual mean wind speed, and mean temperature, were generated and the weights of each of the environmental factors were established by the maximum entropy (MaxEnt) model. We categorized the environmental suitability combined with GIS spatial analysis into three zones, including low-suitable, medium-suitable, and high-suitable region where the cancer mortality ranging from low to high rate was identified. These three zones were quantified by the MaxEnt model taking different air pollutants and meteorological variables into consideration. We identified that NO₂ was a most significant factor among the 6 environmental factors with the weight of 24.88%, followed by the annual mean wind speed, SO₂, and PM₂.₅. The high-suitable area, mainly in the North China Plain which is a most heavily contaminated region by air pollution in China, covers 1.6195 million square kilometers, accounting for 17.85% of the total area investigated in this study. Identification of the impact of various environmental factors on cancer mortality in the different suitable area provides a scientific basis for the environmental management, risk assessment, and lung cancer control.