This study investigated the polycyclic aromatic hydrocarbon (PAH) pollution in the reconstructed land of an abandoned industrial site: a coking plant in Beijing. To meet the needs of urban development, many factories have had to be relocated from city centers, and abandoned industrial sites often need to be transformed into residential land or urban green space through a series of restoration measures. It is necessary to study the level of residual pollutants and potential risks associated with industrial reconstructed land. The concentration of 16 PAHs in the study area ranged from 314.7 to 1618.3 µg/kg, and the average concentration was still at a medium pollution level; the concentration of PAHs in the original coking workshop had the highest levels (1350.5 µg/kg). The PAHs in the soil were mainly low-ring aromatics, especially naphthalene and phenanthrene. The isomer method and principal component analysis indicated that PAHs in the topsoil were the result of coal and biomass combustion. The seven carcinogenic PAHs were the main contributors to the total toxicity equivalence. The genetic toxicity of benzo[a]pyrene was relatively low, and the results were related to the concentration level. There were potential carcinogenic risks for people of varying ages in this residential area. In total, gender differences were small, and the comprehensive lifetime cancer risk level was still acceptable. For the remaining plots at the study site, the daily intake of PAHs by construction workers was between 0.74–2.31 ng/kg bw/day, which requires further evaluation about ignored area occupational exposure to environmental pollutants.

The genotoxicity, mutagenesis, and carcinogenic effects of polycyclic aromatic hydrocarbon (PAH) derivatives may exceed the parent PAHs. However, their influence on the soil environment has not been explored to a large extent. Oxygenated polycyclic aromatic hydrocarbons (OPAHs) and nitrated polycyclic aromatic hydrocarbons (NPAHs) are typical polar substituted compounds. We offer a review of the literature on the sources, quantification, incidence, toxicity, and transport of these compounds in soil. Although their environmental concentrations are lower than those of their parent compounds, they exert higher toxicity. Both types of substances are basically related to carcinogenesis. OPAHs are not enzymatically activated and can generate reactive oxygen species in biological cells, while NPAHs have been shown to be mutagenic, genotoxic, and cytotoxic. These compounds are largely derived from the transformation of PAHs, but they behave differently in soil because of their higher molecular weight and dissimilar adsorption mechanisms. Therefore, specialized knowledge of model derivatives is required. We also made recommendations for future directions based on existing research. It is expected that the review will trigger scientific discussions and provide a research basis for further study on PAH derivatives in the soil environment.

Oil spills in the ocean are becoming an increasingly serious problem and the search for an adsorption material that is effective and environmentally safe is a popular research topic. This study presents a sorbent micro-ball composed of poly-β-hydroxybutyrate. Field emission scanning electron microscopy was used to observe morphology of the micro-ball. Additionally, Fourier transform infrared spectroscopy was used to analyze the surface groups, and nitrogen adsorption was used to determine specific surface area and pore size distribution. The effects of such conditions as initial oil concentration, temperature, pH, and water salinity on the adsorption efficiency were studied. The results show that the equilibration time is 60 min. The adsorption isotherm experiments indicate that the Freundlich model fits the experimental data better than the Langmuir and Henry models, and the adsorption kinetics experimental results show that the pseudo-second-order model fits the experimental data well. The adsorption capacity is proportional to the initial oil concentration. The removal rate increases as the temperature increases, and the adsorption efficacy is highest at a temperature of 25°C. The adsorption capacity varies directly with pH value. Finally, the adsorption capacity of micro-balls increases with increasing seawater salinity.

The littoral width of lakeshores is crucial for maintaining and promoting plant diversity. However, it remains unclear how changes in seasonal water level affect littoral widths by regulating plant diversity and soil nutrient content. This study selected three elevation ranges in the lakeshore of Erhai: supralittoral, eulittoral, and infralittoral. We explored the effects of hydrological changes on littoral widths and their potential relationships by analyzing seasonal differences in plant communities and soil physicochemical properties during an extremely drought year. Our results indicated that the most significant seasonal differences in diversity indices, biomass, and soil physicochemical properties were observed in the eulittoral, followed by the infralittoral and supralittoral. The niche breadths of perennials was significantly decreased by 44.4% and the width of the eulittoral was significantly decreased by 48.6% during the winter. Generalized Additive Models (GAMs) were applied to analyze the elevation distribution ranges of dominant species. The results revealed that species with monotonically increasing distributions had the widest niche breadths, followed by symmetric unimodal species, while monotonically decreasing species exhibited the narrowest. Structural equation modeling revealed a positive and significant correlation between flooding days and soil water content and pH, and a negative correlation with plant parameters (species number, biomass, and coverage). Moreover, plant parameters showed a significant positive correlation with plant diversity. Importantly, plant diversity and soil nutrients were significantly positively correlated with littoral widths, suggesting their key roles in influencing littoral widths. This study highlights the significant impact of hydrological seasonal changes on the littoral widths of lakeshore zones, providing valuable guidance for managing wetland water levels in response to extreme drought events.

Anaerobic polycyclic aromatic hydrocarbons (PAHs) biodegradation is highly important for treating PAHs-contaminated aquifers without oxygen. The aim of this study was to investigate the biodegradation characteristics of benzo(a) pyrene (BaP) in aqueous solution by C. cellulans CWS2 under anaerobic conditions. The degradation characteristics include different temperatures (20–35°C), different pH values (7.0–12.0), and different BaP concentrations (0, 2.5, 5.0, 10.0, 25.0, 50.0 mg/L). The behavior after adding other PAHs and an additional carbon source was also evaluated. C. cellulans CWS2 could degrade BaP at a concentration of 25.0 mg/L in the temperature range of 20–35°C, and approximately 58% of the biodegradation was achieved at 35°C within 10 days at a natural pH. The alkaline conditions of 7.0–10.0 favor biodegradation and reached their highest point at pH 10.0. A BaP concentration of 10.0 mg/L with an initial value of 1.85 at OD600 nm for degradation of the BaP system and a pH of 7.0 was the most ideal condition for obtaining the highest degradation ratio, which was above 80% or higher. C. cellulans CWS2 could degrade phenanthrene and pyrene at the same time, and a low concentration of phenanthrene and pyrene did not reduce BaP degradation. BaP metabolism by C. cellulans CWS2 under anaerobic conditions was the sole carbon and energy source even when there was an additional available carbon source.

Oil spill issues are of great environmental concerns due to the carcinogenic, teratogenic and mutagenic properties of the pollutants such as polycyclic aromatic hydrocarbon (PAH). Biodegradable oil-absorbent microspheres derived from poly-β-hydroxybutyrate (PHB) were synthesized by the double emulsion- solvent (water-in-oil-in-water, W₁/O/W₂) evaporation techniques in this study. The urea-formaldehyde (UF) molar ratio of 4.63 was adopted in the preparation process to allow the nitrogen release at a low rate when they are applied in oil absorption practices. From the emission scanning electron microscopy (SEM) images, the microspheres were found to be porous spherical particles with diameters ranging from 3 to 100 nm. The Fourier transform infrared spectroscopy (FT-IR) spectrum of the oil-absorbent microspheres was proved to be in accordance with that of PHB. The adsorption capability of the microspheres on diesel oil was investigated initially with three serial oil concentrations in water within 240 min. The results showed that the equilibration time was around 60 min and the oil absorbed by the microspheres from oil-water mixture at concentrations of 18.78 and 11.47 mg/g are 53.52 and 49.48% of the adsorption saturation amount in 5 min respectively. The nitrogen release property from the absorbents was also examined and was compared with that of UF through the shaking water-extraction method. Both of the amount and the rate of nitrogen accumulative release were employed as indicators in the process and the maximum total nitrogen concentrations reached at 3 and 4 days for the absorbents and UF respectively.