Steroid estrogens, such as 17β-estradiol (E2), in animal manure pose a potential threat to the aquatic environment. The transport and estrogenicity of estrogens influence the sorption of estrogens to dissolved organic matter (DOM) in animal manure, and composting treatment alters the structure and composition of the manure. The objectives of the present study were to identify the contribution of the molecular composition of DOM of composted manure to the sorption of E2 and then elucidate the dominant mechanisms involved in the interaction of E2 with manure-derived DOM. The excitation–emission matrix (EEM) spectra and atomic force microscopy (AFM) showed that composting significantly altered the chemical composition and structure of DOM. A decrease in the atomic ratios of oxygen (O)/carbon (C) occurred in conjunction with the formation of DOM aggregates in the composted manure, indicating that the hydrophilicity and polarity of the DOM decreased after composting. Composting increased the sorption coefficients (KDOC₋E₂) for E2 to DOM, and KDOC₋E₂ was positively correlated with the proportion of the fulvic acid (FA)-like fraction and molecular weight (MW) fractions of the DOM (range of 1.0 × 10³–7.0 × 10³ Da and 7.0 × 10³–1.4 × 10⁴ Da). Specifically, E2 showed a tendency for sorption to medium-sized FA-like molecules of DOM aggregates in composted manure. Hydrophobic forces and π-π binding appeared to be the main mechanisms underlying the aforementioned interaction.

This study proposed an integrated modelling framework and a modified method for evaluating non-carcinogenic health risks from nonylphenol (NP)-contaminated food consumption. First, a fugacity-based multimedia model and a food web bioaccumulation model were adopted to predict the distribution of NP in the Can Giuoc river and the bioaccumulative concentrations in biota. Next, local people’s exposure to NP was quantified using the accumulative concentrations and the data of fishery products intake from a questionnaire survey distributed among 203 local people. Then, human health risk was evaluated in terms of fishery products intake and intake frequency which were each derived from the same survey. The study revealed that human health risk would exist, although the obtained bioaccumulation factors for the consumed organisms were lower than the bioaccumulation criteria. Consuming 141 g or more per serving of riverine food products resulted in an average NP intake exceeding 0.005 mg/kg of body weight per day among 45–73% of the local adults, of whom pregnant women or young and potential mothers accounted for 10–21%. Seventy-nine percent was the highest rate of the population to be at risk under medium river flow rate when food-intake amount and intake frequency were taken into account. Ingesting 70 g per serving of more contaminated species, such as whiteleg shrimp and small fish, less frequently could lead to less risk exposure than ingesting 267 g per serving of less contaminated species, such as sand goby and climbing pearch, more frequently. By coupling food intake with intake frequency, the modified method enables the studying of human health risk from NP-contaminated food consumption to be conducted with more care, and so benefits risk communication at local level.

Application of medicinal plant to cure ailments has been practiced by several civilizations. Nowadays, contamination of heavy metals and pesticide residues in medicinal plant is a serious concern, due to toxic effects on human health. The present study was designed with an aim to quantify the heavy metals and pesticide residues in the 20 medicinal herbs, frequently sold in the local market as raw material without any quality assurance. The concentrations of the elements are as follows: copper (2.42–19.14 μgg⁻¹), cadmium (0.01–2.10 μgg⁻¹), chromium (17.63–58.63 μgg⁻¹), iron (7.61–322.6 μgg⁻¹), and lead (13.00–54.47 μgg⁻¹), whereas total metal concentration ranged between 44.73 and 385.15 μgg⁻¹. Among the organic pesticides, HCH (1.63–6.44 μgg⁻¹) and DDT (0.63–7.14 μgg⁻¹) isomers were found to be present in medicinal plant material. Result showed that lead and chromium concentrations in the herbs were above the permissible limits set by WHO. These herbs should be regularly checked for quality assurance before using raw or as a herbal formulation to avoid chronic exposure of metal and pesticides to human being.

This study aims to determine the current remediation status of contaminated sites in China to support future decision-making for the cleanup of contaminated sites. A survey was conducted in which a questionnaire was administered to 76 remediation practitioners working across China. The major driving force behind remediation was the redevelopment of contaminated brownfield land for residential purposes, mostly funded by profit-driven developers, particularly in Beijing. A large proportion of brownfield sites have been contaminated with organic compounds, reflecting past land use by chemical plants. Risk assessments of contaminated sites are typically based on the guidelines from China’s Ministry of Ecology and Environment, the United States Environmental Protection Agency, and local governments. The most frequently used criteria to assess site contamination in China are environmental quality standards, screening values, or both. The majority of remediation efforts use low-technology approaches to treat contaminated soil (e.g., cement kiln, in situ and ex situ solidification/stabilization, landfill, and mechanical soil aeration), while sophisticated, high-technology approaches (e.g., in situ and ex situ thermal desorption, in situ chemical treatment, and bioventing) are less often used. The implementation of the latter, while limited, illustrates that the necessary technology exists to support optimal land remediation in China. In addition to high-technology remediation methods, 6W/1H ideology can be employed when assessing contaminated site for remediation. Graphical abstract ᅟ

Diclofenac (DCF), a prevalent anti-inflammatory drug, is frequently detected in aquatic organisms. However, little is known about the environmental factors that affect the bioconcentration of DCF in aquatic environments. Here, we firstly investigated the bioconcentration of DCF by crucian carp (Carassius auratus) following aqueous exposure (3.57, 14.5, and 71.8 μg L⁻¹) for 21 days. DCF can accumulate in crucian carp, and the maximum bioconcentration factors (BCFs) of 121 L kg⁻¹ in the liver, 52.3 L kg⁻¹ in the gills, and 46.8 L kg⁻¹ in the muscle were always found at 3.57 μg L⁻¹ after 14 days of exposure. Secondly, the influences of dissolved organic matter (DOM), feeding, and water flow on the bioconcentration of DCF were determined at the nominal concentration of 4 μg L⁻¹ for 14 days. The BCFs of DCF in various fish tissues decreased by 0.5–85% with the increasing DOM concentrations. Feeding also led to lower body burden of DCF in fish tissues (6–55%) with the increasing food amount. In hydrodynamic experiment, the BCFs of DCF decreased by15–57% at most in various fish tissues. Collectively, our results demonstrated the bioconcentration of DCF in fish can be influenced by various environmental factors, which should be considered in the risk assessment of pharmaceuticals.

Flotation waste of copper slag (FWCS), neutralization sludge (NS), and arsenic-containing gypsum sludge (GS), both of which are difficult to dispose of, are major solid wastes produced by the copper smelting. This study focused on the co-treatment of FWCS, NS, and GS for solidification/stabilization of arsenic and heavy metals with minimal cement clinker. Firstly, the preparation parameters of binder composed of FWCS, NS, and cement clinker were optimized to be FWCS dosage of 40%, NS dosage of 10%, cement clinker dosage of 50%, mill time of 1.5 h, and water-to-binder ratio of 0.25. On these conditions, the unconfined compressive strength (UCS) of the binder reached 43.24 MPa after hydration of 28 days. Then, the binder was used to solidify/stabilize the As-containing GS. When the mass ratio of binder-to-GS was 5:5, the UCS of matrix can reach 11.06 MPa after hydration of 28 days, meeting the required UCS level of MU10 brick in China. Moreover, arsenic and other heavy metals in FWCS, NS, and GS were effectively solidified or stabilized. The heavy metal concentrations in leachate were much lower than those in the limits of China standard leaching test (CSLT). Therefore, the matrices were potential to be used as bricks in some constructions. XRD analysis shows that the main hydration products of the matrix were portlandite and calcium silicate hydrate. These hydration products may play a significant role in the stabilization/solidification of arsenic and heavy metals.

Cadmium (Cd) is a toxic element that poses a great threat to human health, while silicon (Si) is a beneficial element and has been shown to have a mitigation effect on plants under Cd toxicity. However, the mechanisms underlying the role of Si in alleviating Cd toxicity are still poorly understood in wheat. Therefore, growth status, photosynthesis parameters, root morphology, antioxidant system, and Cd²⁺ uptake and flux under Cd toxicity were studied through hydroponic experiment, aiming to explore the mitigation of Si on Cd toxicity in wheat seedlings. The results showed that Si supply improved plant biomass as well as photosynthetic but had little effects on root morphology of seedlings under Cd stress. Si addition decreased Cd contents both in shoots and roots. In situ measurements of Cd²⁺ flux showed that Si significantly inhibited the net Cd²⁺ influx in roots of wheat. Si also mitigated the oxidative stress in wheat leaves by decreasing malondialdialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents as well as by increasing superoxide dismutase (SOD) and guaiacol peroxidase (POD) activity. Overall, the results revealed that Si could alleviate Cd toxicity in wheat seedlings by improving plant growth and antioxidant capacity and by decreasing Cd uptake and lipid peroxidation.

A simple, inexpensive, versatile, and environment-friendly extraction method, using low-temperature partitioning extraction (LTPE), was validated to quantify pharmaceutical-active compounds (PhACs) in surface water samples by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The PhACs analyzed were acetaminophen, bezafibrate, diclofenac, diltiazem, fluconazole, linezolid, miconazole, ondansetron hydrochloride, and trimethoprim. The detection and quantification limits ranged from 0.15 to 12.30 ng L⁻¹ and 0.43 to 40.60 ng L⁻¹, respectively. Recovery rates ranged from 46 to 135%, and relative standard deviation (RSD%) varied between 0.49 and 6.13%. This method was applied to monitor water contamination by PhACs in the Paraopeba River Basin (PRB), Minas Gerais state, Brazil. All PhACs, except linezolid which was not detected, were found in PRB water samples in concentrations that ranged from 2.6 ng L⁻¹ to 2.62 μg L⁻¹.

This study aimed to analyze the risk of infection (influenza and tuberculosis) for individuals participating in physical exercise. This was achieved by assessment of carbon dioxide (CO₂) concentrations, and examination of the physical characteristics of a number of gyms to determine whether there was a relationship to CO₂ levels. This study was performed in three different gyms ventilated with either split system or central system air conditioners. The risk of airborne infection (percent of susceptible persons infected) was estimated for each gym using the Wells-Riley model. The risk of infection increased during periods of peak occupancy where the ventilation required by occupants was greater. In each gym, the highest risk of infection occurred during the evening where occupancy and CO₂ levels were high. The infection risk for influenza was high in all situations due to the high quantum generation rate for this agent. This study suggests that inefficient ventilation in gyms is a significant problem, with high CO₂ concentrations resulting in impaired air quality and high health risks to users, including increased risk of infections such as influenza and tuberculosis.

This study aimed to determine the coupled effects of temperature and urea application rate on kinetic and thermodynamic parameters to supplement the mechanism of urea hydrolysis and modify the Arrhenius model to improve the prediction accuracy of urea content. Laboratory experiments were conducted for sandy loam soil under different temperatures (T) (288, 293, 298, and 308 K) and urea application rates (F) (247, 309, 371, and 433 mg kg⁻¹). Urea content was determined daily through high-performance liquid chromatography. Results showed that the interaction between temperature and urea application rate had a significant effect on reaction rate (Kᵤ) and half-life (H₁/₂), whereas no significant effect on activation degree (lgN), activation free energy (ΔG), activation enthalpy (ΔH), and activation entropy (ΔS). The new Kᵤ(T)-2 model with a determination coefficient (R²) = 0.990 was more accurate than the Arrhenius model with R² = 0.965. The new U(T, F) model with a mean absolute percentage error (MAPE) = 3.62% was more accurate than the traditional U(T) model with a MAPE = 6.38%. The effects of T and F were observed mainly during the preparatory stage and the most critical transition stage of the chemical reaction, respectively. The findings ΔH > 0, ΔG > 0, and ΔS < 0 indicated that urea hydrolysis was endothermic and controlled by enthalpy. These results supplemented the mechanism of urea hydrolysis and improved the prediction accuracy of urea content.