Science of the Total Environment最新文献

Polyhalogenated carbazoles (PHCZs) are emerging organic contaminants and have attracted extensive concern because of their widespread occurrence and dioxin-like toxicity. However, the distribution characteristics, environmental behavior, and fate of PHCZs are still poorly understood. In this study, 74 composite environmental samples from 21 Chinese cities were collected around industrial parks in the Yangtze River Delta. The PHCZ concentration ranges in sediment and soil samples were 12.7-5.21 × 10³ and 34.6-1.81 × 10³ ng/g, respectively, which is equivalent to or higher than those of well-known persistent organic pollutants in the similar areas. The dominant congeners of PHCZs in sediment and soil were 3-chlorocarbazole and 3,6-dichlorocarbazole. Industrial emissions, especially from printing and dyeing textiles, were the main contributors to the high PHCZ environmental concentrations. Potential toxic effects of the PHCZs were evaluated using the toxic equivalent (TEQ) method. The TEQs of PHCZs in sediment and soil were up to 550 and 554 pg TEQ/g dry weight, respectively. The estimated TEQ value of sediment and soil exceeded the corresponding safety guideline, which indicated that PHCZs in the Yangtze River Delta posed high health risks. This study provides an important theoretical basis for controlling and reducing the ecological risks of PHCZs in the chemical industry. At the same time, it also provides reference for the priority control and revision of discharge standards for PHCZs in sewage treatment plants in future.

Biochar application emerges as a valuable soil management strategy for enhancing crop yield; however, the mechanisms underlying the relationships between soil and plants remain unclear after biochar application. In this study, soil pore characteristics and maize yield were assessed in a five-year biochar-application experiment on the Loess Plateau of China, including four treatments: Control (no biochar), low-dose biochar application (LB, 3 t ha^-1), moderate-dose biochar application (MB, 6 t ha^-1), and high-dose biochar application (HB, 9 t ha^-1). Root growth traits were evaluated by cultivating maize in intact soil cores collected from field conditions using X-ray computed tomography. Our findings indicate that, compared to the Control, the HB treatment enhanced macroporosity (> 0.1 mm in diameter), porosity of 0.1-0.5 mm pores, and saturated water content, while reducing macropore connectivity and penetration resistance. However, biochar application treatments did not alter the water retention characteristics from field capacity to permanent wilting point or the plant-available water content (PAWC). Furthermore, the mean angle of primary and seminal roots as well as the length and surface area of entire roots increased in the HB treatment, showing a positive correlation with the porosity of 0.1-0.5 mm pores. The mean diameter of primary and seminal roots, leaf fresh and dry weights, and maize yield also increased in the HB treatment compared to the Control. Partial least squares path modeling analysis indicated that biochar application rates positively impacted on root growth and plant productivity through an indirect influence of soil pore size distribution, with 0.1-0.5 mm pores being particularly crucial for facilitating deeper root penetration and root elongation. These findings demonstrate that biochar application primarily augmented 0.1-0.5 mm pores, rather than affecting smaller pores capable of retaining plant-available water or larger macropores, enhancing deeper rooting and root elongation, thus improving plant productivity and crop yield.

Coking releases large quantities of multiple polycyclic aromatic hydrocarbons (PAHs), yet previous research has often focused on only a limited subset. This may not fully represent the overall risk posed by aromatic compounds. Here, a novel non-target analysis method was developed to identify more emerging PAHs and benzofuran derivatives. Beyond the 16 US Environmental Protection Agency priority PAHs (EPA PAHs), 56 emerging PAHs, 64 alkylated PAHs, and 32 furans were identified, with 69 compounds identified for the first time. The Σ₁₆ EPA PAHs, Σ₅₆ emerging PAHs, Σ₆₄ alkylated PAHs, and Σ₃₂ furans concentration ranges were 0.30-6910, 0.01-2187, 0.52-1649, and 0.06-588 μg/g, respectively. Emerging PAHs and furans had higher contributions in the plant area than the control area. Some PAHs and furans' concentrations were not significantly associated with the EPA PAHs; therefore, the EPA PAHs are insufficient to represent the totals PAHs concentration or risk. In the top 20 % of toxicological priority compounds, the emerging PAHs concentrations were 50 % of those of the EPA PAHs but posed 3.4 times the carcinogenic risk. Four of these compounds had higher carcinogenic risks than the EPA PAHs, while another nine had comparable risks. Thus, the risks of emerging PAHs cannot be ignored. Future monitoring and control of PAHs and furan emissions by the coking industry are highly recommended.

In the backdrop of China's 'Carbon peak, Carbon neutrality' goal, to reduce the pollution caused by carbon emissions to the atmosphere, this study investigates the supply of biomass briquette fuel. The supply of biomass briquette fuel is generally divided into two stages: the first stage involves the collection, storage, and transportation of biomass straw to the biomass briquette production base; the second encompasses the processing of the biomass straw into briquette fuel at the production base, followed by its transportation to the biomass boiler heating center for utilization. In this paper, a mathematical model is developed based on carbon emission and economic cost. The model is then calculated with an optimized intelligent algorithm, and the results are subjected to sensitivity analysis. The results demonstrate that: (1) Compared to the pre-optimization phase, the optimized model increases profits by 26.31 % and reduces carbon emissions by 12.64 %. (2) The adaptive genetic algorithm shows significantly better convergence speed and accuracy compared to the traditional genetic algorithm, making it more suitable for intelligent calculations of biomass briquette fuel supply. (3) As the weight coefficient of carbon emissions increases, economic costs continue to decrease with increasing sensitivity, while carbon emissions continue to decrease with decreasing sensitivity. These results provide references for further optimizing the weight coefficients of economic costs and carbon emissions in the supply of briquette fuel. This study contributes to reducing carbon emissions and provide references for the rational and intelligent supply of biomass briquette fuel.

To strengthen the control of pollution sources and promote soil pollution management of agricultural land, this study constructed a comprehensive source apportionment framework, which significantly improved the reliability of potential source analysis compared with the traditional single model. The spatial distribution pattern of agricultural soil heavy metals (SHMs) content in Lintong, a typical river valley city in China, was determined and the degree of contamination was evaluated. A scientific source apportionment methodological framework was constructed through correlation analysis methods together with multiple source apportionment receptor models. Finally, the Monte Carlo simulation method was used to derive the results of the human health risk assessment (HHRA). The results revealed the following: (1) Agricultural soils were moderately and mildly polluted, accounting for 28.8 % and 71.2 % of the total number of sampling points, respectively. (2) The overall correlation of heavy metals (HMs) was strong according to the coupling analysis of the SHMs, in which a strong correlation (0.8-1) was reached among Cu, Ni, Pb, Cr and Zn, indicating that these HMs were most likely homologous or composite. (3) Multimodel analysis of the SHMs sources revealed that the first and second principal components were agricultural (41.36 %) and industrial (19.69 %) sources, respectively, and the remaining principal components were road traffic, natural factors, and atmospheric deposition or surface runoff, respectively. (4) The average comprehensive noncarcinogenic health risk indices for adults and children were 4.2259E-02 and 1.4194E-01, respectively, which were within the slight risk range, indicating that the risk caused by SHMs to the human body can be almost negligible. This study adopted a mixed method to reveal the risk of SHMs pollution and its sources, which provides some reference and technical support for traceability analysis, zoning control, and health risk studies of regional pollutants and is helpful for formulating scientific management measures and targeting control policies.

Rapid and uncontrolled urbanization in sub-Saharan Africa has led to an increased production and expansion of synthetic chemicals, resulting in significant pollution of the aquatic environments, particularly by Emerging Organic Contaminants (EOCs). Due to the low income of the population in this region, there is often a lack of control over water and fishery resources prior to consumption. Therefore, the current study aims to use EOCs as markers of water resource quality degradation, and to assess the potential environmental risk of these compounds on some aquatic organisms. Among 120 targeted compounds, 66 were detected at 22 sites in Douala city, Cameroon, including 9 rivers and 13 groundwater samples. The detected EOCs were classified into three categories, including pharmaceuticals and personal care products (n = 55), lifestyle compounds (n = 7) and industrial compounds (n = 4). Surface water was highly impacted, with EOC total concentrations reaching 61,273 ng/L, versus 16,677 ng/L in groundwater. Contamination levels and the type of contaminants were closely linked to land use patterns in the study area. Contamination was mainly attributed to domestic, hospital and brewery's industry wastewaters, landfill and pit latrines. Consumption patterns and physicochemical properties of compounds, in particular their persistence, polarity and octanol/water gradient (Kow), explain their occurrence at high concentrations (up to μg/L) in groundwater. According to Risk Quotient (RQ) with a maximum of 93.4 in surface water and 8.5 in groundwater, about 1/3 of the identified compounds pose a serious threat to aquatic organisms, including algae, invertebrates and fish. For the first time in Central African, we revealed these high levels of water contamination by EOCs and identified the risk for the environmental health. Our study demonstrates the urgency to adopt sustainable water management strategies in large cities of the region.

Natural attenuation of naphthalene (NAP) in riverbank filtration zones is vital for maintaining water quality and is affected by dissolved organic matter (DOM) and iron minerals. However, the effects of DOM and iron minerals on the attenuation of NAP remain unclear. In this study, the attenuation mechanisms of NAP under the influence of DOM and iron minerals were explored in a riverside source area. Field dynamic monitoring data revealed that the NAP concentration in groundwater is mainly influenced by DOM, effective bound‑iron, and the intensity of river water infiltration recharge. Column experiments indicated that DOM with α-Fe₂O₃ or α-FeO(OH) reduced medium permeability by 8.16 % or 6.85 %, respectively, increasing water retention time. However, they had different effects on the attenuation of NAP. The coexistence of α-Fe₂O₃ and DOM enhanced NAP attenuation capacity by 9.13 %-45.91 %, while α-FeO(OH) and DOM reduced it by -13.25 % to -24.13 %. These effects were attributed to changes in the medium permeability, particle size, secondary mineral formation, and microbial community structure. Specifically, α-Fe₂O₃ and DOM reduced medium permeability, increasing the adsorption and biodegradation reaction time of NAP, and promoted secondary mineral (FeCO₃) formation, increasing the adsorption capacity of medium for NAP, while α-FeO(OH) and DOM underwent cementation, resulting in larger particles and reduced adsorption capacity for NAP. Additionally, α-FeO(OH) and DOM promoted Shewanlla growth, inhibiting NAP attenuation by competing with NAP-degrading bacteria. These findings improve the understanding of the natural attenuation of polycyclic aromatic hydrocarbons (PAHs) in riverbank filtration, offering a basis for evaluating and controlling PAH pollution risks.

Polymetallic nodules containing manganese, iron, and other metals are found in the seafloor. Leachates of polymetallic nodules can be discharged into seawater during ocean mining, disrupting marine ecosystems and causing adverse effects on marine organisms. Here, we investigate the acute and chronic effects of two polymetallic nodule leachates on the life-history parameters (mortality, development, and fecundity) and transcriptional differences of detoxification, antioxidant, and reproduction-related genes for cytochrome P450, glutathione S-transferase, and vitellogenin in the marine copepod Tigriopus koreanus. We also examine single and combined effects for six metals whose concentrations differ between the two leachates. No significant changes in mortality were observed, but developmental time was significantly shortened and fecundity increased in T. koreanus in response to exposure to the leachates. No adverse effects on physiological parameters were seen, but transcriptional differences by leachates were evident. In addition, manganese and iron in the leachates improved copepod development when they were combined with other metals. The findings of this study elucidate the potential impact of polymetallic nodule leachates on marine copepods.

Cadmium (Cd) is a toxic heavy metal widespread in rice paddies and threatens food safety and human health. Foliar exposure represents a cost-effective, simple, and time-independent approach to enhance rice resistance and minimize Cd accumulation. Herein, foliar spraying of carbon dots (CDs) was found to significantly reduce Cd accumulation in rice roots and shoots by 31.51 % and 17.93 %, respectively. Gene expression and mineral nutrient analyses indicated that CDs exposure inhibited Cd uptake by suppressing OsNramp1 and increasing competition of Fe and Mn with Cd for OsNramp5. Besides, CDs exposure down-regulated OsHMA2 for Cd transport from roots to aerial parts and up-regulated OsHMA3 for Cd vacuole sequestration. Additionally, CDs treatment promoted rice root development by increasing root biomass, cell walls, and mechanical resistance, which helped to anchor rice plants and impede Cd uptake. Furthermore, CDs spraying increased the organic carbon content and altered the microbial communities in the rice rhizosphere by increasing root exudation. This process facilitated the binding of dissolved Cd in pore water to organic matter and iron‑manganese oxides, ultimately reducing the bioavailability of Cd. This study underscores the effectiveness and mechanism of simple foliar spraying of CDs to mitigate Cd accumulation in rice.

Biochar is a carbonaceous material that can be amplified into nano-biochar (N-BC) using different physicochemical techniques. Contrary to bulk biochar, nano-biochar, and have better physicochemical characteristics, including a large specific surface area, pore properties, distinctive nanostructure, and high catalytic activity. The spotlight of this review is to contribute up-to-date information on the scaling up of biochar into nano-biochar through various sustainable techniques. This review paper is a compilation of research on nano-biochar from biochar including preparation, distinctive characteristics, and intended applications in the environmental and agricultural sectors, along with some other cutting-edge applications, which are all covered in detail in this review paper and also provides the knowledge gap that will be useful for future investigation and development.