Typical Persistent Organic Pollutants Research Articles

Insights into hydrangea-like NiCo2S4 activating peroxymonosulfate for efficient degradation of atrazine

Developing a highly efficient heterogeneous catalyst for activating peroxymonosulfate (PMS) in the degradation of persistent organic pollutants (POPs) remains a challenge, and transition bimetallic sulfide is considered a promising candidate. Herein, a hydrangea-like NiCo2S4 was designed for activating PMS in the removal of a typical POP (atrazine, ATZ), and the activation mechanism of the catalyst was elucidated. The hydrangea-like NiCo2S4 was successfully synthesized through sulfide ion-exchange with its oxide counterpart (NiCo2O4), showing much more excellent catalytic performance in activating PMS than NiCo2O4 for the degradation of ATZ. The ATZ (46 μM) degradation efficiency (RD) in the NiCo2S4/PMS system (40 mg L−1 catalyst and 0.4 mM PMS) achieves nearly 100 % within 10 min with an apparent rate constant (k) of 0.583 min−1, superior to those of NiCo2O4/PMS system with values of RD = 26.7 % and k = 0.033 min−1. The role of sulfur species was uncovered and the origin of the exceptional catalytic performance of NiCo2S4 was disclosed through various techniques. The results demonstrated that sulfur species not only accelerated electron transfer but also promoted the regeneration of reactive sites by facilitating the conversion of Co3+/Ni3+ to Co2+/Ni2+. More reactive oxygen species (ROSs), including sulfate radical (SO4•−), hydroxyl radical (•OH), superoxide radical (O2•−) and singlet oxygen (1O2) were produced for attacking ATZ molecules, leading to their degradation into the intermediates with reduced toxicity.

Design of Bi4O5Br2/g‐C3N4 heterojunction for efficient photocatalytic removal of persistent organic pollutants from water

AbstractDyes and antibiotics as typical persistent organic pollutants (POPs) are widely present in the environment, but can hardly be removed completely by traditional water treatment methods. Here, we designed Bi4O5Br2/g‐C3N4 composite nanosheets for efficient photocatalytic removal of POPs in water. The Bi4O5Br2/g‐C3N4 composite with a heterojunction structure exhibited high adsorption and photocatalytic activity for removal of tetracycline (TC) and ciprofloxacin (CIP) with excellent cyclic stability, owing to its large specific surface area as well as enhanced charge separation and visible light utilization. Our characterization revealed that h+ and ·OH are responsible for the photocatalytic degradation of TC and CIP. This work provides insights into the design of photocatalytic materials with synergy of adsorption and photocatalytic degradation, and offers a heterojunction construction strategy for addressing the increasingly severe environmental issues.

Cannabidiol alleviates perfluorooctane sulfonate-induced macrophage extracellular trap mediate inflammation and fibrosis in mice liver

As a new type of persistent organic pollutant, perfluorooctane sulphonate (PFOS) has received extensive attention worldwide. Cannabidiol (CBD) is a non-psychoactive natural cannabinoid extract that has been proved to have antioxidation, regulation of inflammation and other functions. However, the effects of PFOS on liver injury and whether CBD can alleviate PFOS-induced liver injury are still unclear. Therefore, in this study, we used CBD (10 mg/kg) and/or PFOS (5 mg/kg) to intraperitoneally inject mice for 30 days. We found that PFOS exposure led to inflammatory infiltration in the liver of mice, increased the formation of macrophage extracellular trap (MET), and promoted fibrosis. In vitro, we established a coculture system of RAW264.7, AML12 and LX-2 cells, and treated them with CBD (10 μM) and/or PFOS (200 μM). The results showed that PFOS could also induce the expression of MET, inflammation and fibrosis marker genes in vitro. Coiled-coil domain containing protein 25 (CCD25), as a MET-DNA sensor, was used to investigate its ability to regulate inflammation and fibrosis, we knocked down CCDC25 and its downstream proteins (integrin-linked kinase, ILK) by siRNA technology, and used QNZ to inhibit NF-κB pathway. The results showed that the knockdown of CCDC25 and ILK and the inhibition of NF-κB pathway could inhibit MET-induced inflammation and fibrosis marker gene expression. In summary, we found that PFOS-induced MET can promote inflammation and fibrosis through the CCDC25-ILK-NF-κB signaling axis, while the treatment of CBD showed a protective effect, and it is proved by Macromolecular docking that this protective effect is achieved by combining CBD with peptidylarginine deiminase 4 (PAD4) to alleviate the release of MET. Therefore, regulating the formation of MET and the CCDC25-ILK-NF-κB signaling axis is an innovative treatment option that can effectively reduce hepatotoxicity. Our study reveals the mechanism of PFOS-induced hepatotoxicity and provides promising insights into the protective role of CBD in this process.

Distribution, Source, and Ecological Risk Assessment of Persistent Organic Pollutants in Surface Sediments of Boao Coastal Waters

Persistent organic pollutants (POPs) in the environment have the characteristics of persistence, bioaccumulation, teratogenicity, carcinogenicity, and mutagenicity. Long-term exposure of low-content POPs will also have a certain impact on marine ecosystems and human beings. The contents of three typical persistent organic pollutants[polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polycyclic biphenyls (PCBs)] of surface sediments were analyzed using gas chromatography and mass spectrometry (GC-MS) to assess the pollution characteristics of persistent organic pollutants in Boao coastal waters. The distribution and source of persistent organic pollutants were analyzed in this study, and the ecological risk was assessed using three different methods:the effect interval low/median method (ERL/ERM), mean effect interval median quotient method (M-ERM-Q), and mean potential impact concentration quotient method (M-PEC-Q). The results indicated that the contents (measured by dry weight) of ΣPAHs, ΣOCPs, and ΣPCBs in the study area were 4.5-367.50, 3.99-175.30, and ND-2.89 ng·g-1, respectively, which were at a low level, and the overall distribution showed a trend of gradually increasing toward the sea. The results of POPs source analysis showed that the PAHs in the study area were mainly from the combustion of wood and coal. Among OCPs, the HCH was mainly from lindane, the historical land-based input had been completely degraded, and the DDT was mainly the traditional DDTs pesticides, with additional continuous DDT input. The PCBs were primarily pentachlorobiphenyls, which might have come from the release of paint on the bottom of the hull in the early stage of shipping and the peeling off of paint from old ships. The ecological risk assessment results showed that there was little difference among the assessment results of the three methods, which showed that only phenanthrene monomer of PAHs in the study area had a slight negative impact, and the DDT and the γ-HCH among PAHs would cause great ecological risk, whereas PCBs and other pollutants would not cause ecological risk. On the whole, the possibility of comprehensive ecological risk caused by the three pollutants was very small.

Regulation of friction pair to promote conversion of mechanical energy to chemical energy on Bi2WO6 and realization of enhanced tribocatalytic activity to degrade different pollutants

Recently, friction-induced tribocatalysis has received tremendous attention through converting mechanical energy to chemical energy. However, its efficiency is much lower than those of photocatalysis and piezocatalysis, and its environmental application is limited in dye degradation. Herein, we developed a facile approach to improve the tribocatalytic activity of Bi2WO6 via adding trace polymer powders to form friction pairs with Bi2WO6. Among various polymers, PTFE was demonstrated to be the best counterpart of Bi2WO6. Subsequently, the PTFE dosage, stirring rate, magnetic bar size and number, and stirring mode were further optimized. The PTFE-promoted Bi2WO6 tribocatalysis was verified to possess excellent performance not only for removing different dyes, but also for degrading chlorophenols that are typical persistent organic pollutants. Multiple uses of the recycled catalysts indicated its good stability and prominent tribocatalytic durability. EPR measurements suggested the generation of hydroxyl radical and superoxide radical, which were determined to be continuously generated within 12 h at the rates of 0.88 μM h−1 and 85 μM h−1, respectively. Subsequently, a possible mechanism was proposed to explain the enhanced performance of the PTFE-promoted Bi2WO6 tribocatalysis. Finally, on basis of the detected intermediates, the degradation pathways of Rhodamine B and 2,4-Dichlorophenol during tribocatalysis were suggested.

LEGAL REGULATIONS IN THE FIELD OF POLYCHLORINATED BIPHENYLS MANAGEMENT

Polychlorinated biphenyls are a type of persistent organic pollutants that have been produced all over the world due to their favorable physicochemical properties. After the prohibition of their production and use, they have become a serious problem in terms of the destruction of existing quantities bearing in mind their wide and varied application. They are still capable of being released into the atmosphere today. As they are still present in the environment, an important issue of the environmental protection policy is the legal regulation of polychlorinated biphenyls management. On the international level, the Stockholm, Basel and Rotterdam Conventions are particularly important. On the national level, the Law on Chemicals, the Law on Waste Management and the Rulebook on Restrictions and Prohibitions on the Production, Placing on the Market and Use of Chemicals are of particular importance in this area.

Amino Acid Transporter as a Potential Carrier Protein for the Root-to-Shoot Translocation of Polybrominated Diphenyl Ethers in Rice.

As typical persistent organic pollutants, polybrominated diphenyl ethers (PBDEs) tend to accumulate in edible parts of rice, posing great ecological and health risks. The translocation of PBDEs from underground to aboveground parts of rice is a crucial procedure to determine the final bioaccumulation level. Herein, this study aimed to identify the transporter proteins for PBDEs in rice plants in order to strengthen our understanding of the bioaccumulation mechanism and the potential prevention strategy of the PBDE risk. Similar time-dependent patterns were observed among the root-to-shoot translocation factors (TFs) of PBDEs, the expression of lysine histidine transporter (LHT) protein, and the relative levels of LHT substrates (phenylalanine or tyrosine), implying the potential co-transport of PBDEs, phenylalanine, and tyrosine by the carrier LHT. Fluorescence spectra and circular dichroism showed that PBDE congeners interfered with LHT via static fluorescence quenching and changes in the protein's secondary structure. The in vitro sorption fraction of LHT to PBDEs, as revealed by sorption equilibrium analysis, was comparable to the in vivo TF values. Knockout of OsLHT1 in rice using CRISPR/Cas9 technology caused a 48.2-78.4% decrease in PBDE translocation. Molecular docking simulation suggested that PBDEs, phenylalanine, and tyrosine were inserted into the same ligand-binding cavity of LHT, substantiating the potential carrier role of LHT for PBDEs from a conformational perspective. Quantitative structure activity relationship analysis demonstrated that the ether-bond oxygen and the carbons at the site 4 and 4' of PBDE molecules are significant determinants of the binding affinity with the LHT protein and in vivo translocation of PBDEs. In summary, this study discovered that LHT acts as the cellular carrier for PBDEs and offered a comprehensive molecular explanation for the bioaccumulation and translocation of PBDEs in rice plants, covering both biological and chemical perspectives. These findings fill in a knowledge gap on the endogenous transporter proteins for exogenous organic pollutants.

Insights into the effects of hydrogen peroxide and Fenton oxidation on PAHs removal and indigenous microorganisms in a coking-contaminated soil

Polycyclic aromatic hydrocarbons (PAHs) are typical persistent organic pollutants in the coking-contaminated soil, however, the effects of chemical oxidation on PAHs removal and the responses of indigenous microorganisms in slurry system has not been studied. In this study, the removal efficiency of PAHs and the responses of indigenous microorganisms treated by hydrogen peroxide (H2O2) and Fenton oxidation under different liquid-to-solid (L/S) ratio were investigated. The results showed that the highest removal efficiency of Σ PAHs treated by H2O2 oxidation was at the L/S ratio of 4:1. At such condition, the order of PAHs removal efficiency from high to low was 3-ring PAHs (69.7%–99.9%), followed by high ring PAHs (4-6 rings, 54.5%–95.5%), and 2-ring PAHs (38.1%–52.4%). However, Fenton oxidation had insignificantly increased the removal efficiency of PAHs, partly because the high content of metal cations (i.e., Fe2＋ and Mn2+) in coking contaminated soil. The number of soil microorganisms changed slightly during H2O2 and Fenton oxidation treatments (∼10 8 copies/g), while the bacterial diversity increased significantly. Microbial function analysis suggested that the carbohydrate metabolism, xenobiotics biodegradation and metabolism mainly contributed to the degradation of PAHs. Moreover, the function genes and pathways (i.e., amino sugar metabolism and citrate cycle) that involved in PAHs biodegradation increased, which can further promote the biological degradation of PAHs by indigenous microorganisms.

Estradiol protects female mice from hyperuricemia induced by PCB138 exposure

Polychlorinated biphenyls (PCBs) are a type of persistent organic pollutant (POP). Our previous study demonstrated that exposure to 0.5–50 μg/kg bw PCB138 during postnatal days (PND) 3–21 led to elevated serum uric acid (UA) levels and kidney injury in adult male mice. Given that the prevalence of hyperuricemia (HUA) is significantly lower in women than in men, it is worth investigating whether POP-induced HUA and its secondary kidney injury have sexual dimorphism. Herein, we exposed female mice to 0.5–50 μg/kg bw PCB138 during PND 3–21, resulting in elevated serum UA levels, but without causing significant kidney damage. Concurrently, we found a negative correlation between serum 17β-estradiol (E2) and serum UA levels. We also observed down-regulation of estrogen receptor (ER) protein levels in the kidneys of the PCB138-exposed groups. Furthermore, our study showed that E2 rescued the increased UA level and cytotoxicity caused by HUA in human renal tubular epithelial (HK-2) cells. Collectively, our findings suggest that E2 likely plays a crucial protective role in PCB138-induced HUA and kidney injury in female mice. Our research highlights the existence of sexual dimorphism in kidney injury secondary to HUA induced by POPs, which could provide guidance for individuals of different genders in preventing kidney injury caused by environmental factors.

Determining the degradation mechanism and application potential of benzopyrene-degrading bacterium Acinetobacter XS-4 by screening

In industrial wastewater treatment, organic pollutants are usually removed by in-situ microorganisms and exogenous bactericides. Benzo [a] pyrene (BaP) is a typical persistent organic pollutant and difficult to be removed. In this study, a new strain of BaP degrading bacteria Acinetobacter XS-4 was obtained and the degradation rate was optimized by response surface method. The results showed that the degradation rate of BaP was 62.73% when pH= 8, substrate concentration was 10 mg/L, temperature was 25 °C, inoculation amount was 15% and culture rate was 180 r/min. Its degradation rate was better than that of the reported degrading bacteria. XS-4 is active in the degradation of BaP. BaP is degraded into phenanthrene by 3, 4-dioxygenase (α subunit and β subunit) in pathway Ⅰ and rapidly forms aldehydes, esters and alkanes. The pathway Ⅱ is realized by the action of salicylic acid hydroxylase. When sodium alginate and polyvinyl alcohol were added to the actual coking wastewater to immobilize XS-4, the degradation rate of BaP was 72.68% after 7 days, and the removal effect was better than that of single BaP wastewater (62.36%), which has the application potential. This study provides theoretical and technical support for microbial degradation of BaP in industrial wastewater.

The fate of three typical persistent organic pollutants in bioretention columns as revealed by stable carbon isotopes

There is a lack of simple and effective methods to quantify the fate processes of persistent organic pollutants (POPs) in bioretention systems. In this study, the fate and elimination processes of three typical 13C-labeled POPs in regularly added bioretention columns were quantified using stable carbon isotope analysis techniques. The results showed that the modified media bioretention column removed more than 90% of Pyrene, PCB169 and p,p'-DDT. Media adsorption was the dominant removal mechanism for the reduction of the three exogenous organic compounds (59.1–71.8% of the input) although plant uptake (5.9–18.0%) was also important. Mineralization was effective in degrading pyrene (13.1%) but had a very limited effect on p,p'-DDT and PCB169 removal (<2.0%), the reason for which may be related to the aerobic conditions of the filter column. Volatilization was relatively weak and negligible (<1.5%). The presence of heavy metals inhibited the removal of POPs to some extent: media adsorption, mineralization and plant uptake were reduced by 4.3–6.4%, 1.8–8.3% and 1.5–3.6% respectively. This study suggests that bioretention systems are an effective measure for the sustainable removal of POPs from stormwater and that heavy metals can inhibit the overall performance of the system. Stable carbon isotope analysis techniques can help to investigate the migration and transformation of POPs in bioretention systems.

Hippocampal Proteomics Reveals the Role of Glutamatergic Synapse Activation in the Depression Induced by Perfluorooctane Sulfonate

Perfluorooctane sulfonate (PFOS), a new type of persistent organic pollutant in the environment of water, has drawn significant attention in recent years due to its widespread prevalence and high toxicity. Neurotoxicity is regarded as one of the major toxic effects of PFOS, while research studies on PFOS-induced depression and the underlying mechanisms remain scarce. In this study, behavioral tests revealed the depressive-like behaviors in PFOS-exposed male mice. Neuron damages including pyknosis and staining deepening were identified through hematoxylin and eosin staining. Then, we noticed the elevation of glutamate and proline levels as well as the decline of glutamine and tryptophan levels. Proteomics analysis identified 105 differentially expressed proteins that change in a dose-dependent manner and revealed that PFOS exposure activated the glutamatergic synapse signaling pathway, which were further confirmed by Western blot, and the data were consistent with the findings of the proteomics analysis. Additionally, the downstream signaling cyclic AMP-responsive element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) and synaptic plasticity-related postsynaptic density protein 95, synaptophysin, were downregulated. Our results highlight that PFOS exposure may inhibit the synaptic plasticity of the hippocampus via glutamatergic synapse and the CREB/BDNF signaling pathway to cause depressive-like behaviors in male mice.

BPDE exposure promotes trophoblast cell pyroptosis and induces miscarriage by up-regulating lnc-HZ14/ZBP1/NLRP3 axis

Environmental Benzo(a)pyrene (BaP) and its ultimate metabolite BPDE (benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide) are typical persistent organic pollutants and endocrine disrupting chemicals. BaP/BPDE exposure might cause human trophoblast cell dysfunctions and induce miscarriage. However, the underlying mechanisms remain largely elusive. In this study, we found that BPDE exposure induced human trophoblast cell pyroptosis by up-regulating NLRP3/Caspase1/GSDMD pathway. We also identified that lnc-HZ14 was highly expressed in BPDE-exposed trophoblast cells and in recurrent miscarriage (RM) vs healthy control (HC) villous tissues. Lnc-HZ14 promoted trophoblast cell pyroptosis by promoting IRF1-mediated ZBP1 transcription, increasing METTL3-mediated m6A methylation on NLRP3 mRNA and its stability, and also enhancing ZBP1/NLRP3 protein interactions. Knockdown of lnc-HZ14/ZBP1/NLRP3 axis could efficiently alleviate BPDE-induced trophoblast cell pyroptosis. Higher level of pyroptosis, as indicated by the up-regulation of lnc-HZ14/ZBP1/NLRP3 axis, was found in RM vs HC villous tissues. In BaP-exposed mouse model, BaP exposure induced placental tissue pyroptosis and miscarriage by up-regulating murine Zbp1/Nlrp3 axis, and knockdown of Nlrp3 could efficiently reduce placenta pyroptosis and alleviate BaP-induced mouse miscarriage. Serum IL-1β protein level might act as a promising indicator to predict the risk of miscarriage. These findings provided new insights into BaP/BPDE-induced trophoblast cell pyroptosis and miscarriage and might be helpful for further assessment of the toxicological effects of BaP/BPDE on the female reproduction.

The Spatial Distribution and Potential Risk Assessment of POPs in Farmland around a Typical E-Waste Dismantling Site.

Pollution from electronic-waste (E-waste) dismantling is of great concern. This study investigated the concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) in 253 cropland soil samples around an abandoned E-waste dismantling site in Taizhou city, Zhejiang province in China, using an analytical method which simultaneously extracted, purified and determined the identity and quantity of the three types of persistent organic pollutants. Meanwhile, their spatial distributions, pollution characteristics, and risk assessments were further analyzed. Total PCBs in the test soils ranged from below method detection limits (ND) to 2985.25μgkg-1 on a dry weight basis (d.w.), and the spatial distribution indicated a "hot spot" of PCBs pollution in the study area. The PAHs were detected in all samples with total concentrations ranging from 4.99 to 2723.06μgkg-1d.w. The distribution of PBDEs showed the pollution characteristics of "family-run workshops", with a total content range of ND ~ 899.34μgkg-1d.w., of which BDE209 was typically the dominant congener, accounting for 74.05% of the total PBDEs content in the test soils, with the highest content reaching 857.72μgkg-1d.w. Results showed that the ecological and lifetime carcinogenic risks of PCBs and PAHs were low in the study area, but the health risk caused by oral ingestion and dermal contact accounted for the highest proportion of the total exposure risks, while inhalation could be ignored. PBDEs in soils of the study area were a potential chronic non-carcinogenic risk, particularly for children. Therefore, in order to protect human health and environment, it is necessary to regulate the management of E-waste dismantling sites and pollution control.

DETERMINATION OF POLYCHLORINATED BIPHENYLS (PCBs) IN SURFACE WATER IN ONDO STATE NIGERIA

Polychlorinated biphenyl compounds (PCBs) were included to the Stockholm Convention's list of typical persistent organic pollutants on May 22, 2001. (POPs). Humans have produced PCBs, which are pervasive in the environment. They are a concern for people all around the world because of their toxic, bioaccumulative, long-lasting, hydrophobic, and transboundary characteristics. The study's goals included describing how PCBs are distributed in surface water and evaluating how certain physiochemical factors affect PCB concentrations. Five separate Okitipupa locations—OAUSTECH, Igodan, Okunmo, Idepe, and Lebi/Ofe River—had their water samples taken. The overall average concentration of PCBs discovered in the samples taken from five (5) distinct places was determined to be as follows: OAUSTECH (5.720.13), Igodan (5.520.00), Okunmo (3.480.03), Idepe (21.830.02), and Lebi/Ofe (0.160.00), with their combined probability being determined to be 0.001. Twenty-five (25) PCB congeners were examined using a gas chromatography-electron capture detector (GC-ECD). The majority of congeners were below the detection threshold at every site. Total PCB values varied from 0.16 g/L to 21.83 g/L. The correlation between the overall level of polychlorinated biphenyls and the total organic carbon was positive (0.214), but it was weak (PCBs) and pH, positive (0.096) but poor correlation between the electrical conductivity, and a positive (0.220). The levels found in this investigation, with the exception of one area, were obviously lower than the 0.5μg/l level advised by the WHO. The water's concentration of polychlorinated biphenyls (PCBs) is not significantly impacted by the physicochemical characteristics, and the water is safe to use for household purposes.

Effects of dibutyl phthalate on microbial community and the carbon cycle in salinized soil

Dibutyl phthalate (DBP), a typical persistent organic pollutant, is of extensive attention because of its universal detection in soils and its impact on soil ecology. However, the ecological effects of DBP on ecologically fragile salinized soils are unclear, especially as soil salinization can result in soil degradation and thus affect the soil carbon cycle. Therefore, in this study, a typical salinized soil (agricultural soil in the Yellow River Delta) was selected and treated with DBP at different doses (1.0, 10, and 50 mg kg−1) and incubated for 30 d. The results revealed that DBP exposure significantly decreased the abundance of soil microorganisms. Molecular ecological network analysis showed that some taxa related to the carbon cycle gradually became key taxa in the network, changing the composition and structure of the bacterial community. The decrease of cbbLG, cbbLR and cex, and the increase of sga, glx and mcrA functional gene abundance affected carbon conversion. Molecular docking indicated that DBP could bind to soil invertase and β-glucosidase proteins, and change the enzyme activity. These results emphasized the critical impact of DBP on microbial communities and carbon cycling in salinized soils, and will play an essential role in DBP ecological risk assessment.

Analysis of the Degradation of OCPs Contaminated Soil by the BC/nZVI Combined with Indigenous Microorganisms.

Organochlorine pesticides (OCPs) were typical persistent organic pollutants that posed great hazards and high risks in soil. In this study, a peanut shell biochar-loaded nano zero-valent iron (BC/nZVI) material was prepared in combination with soil indigenous microorganisms to enhance the degradation of α-hexachlorocyclohexane(α-HCH) and γ-hexachlorocyclohexane(γ-HCH) in water and soil. The effects of BC/nZVI on indigenous microorganisms in soil were investigated based on the changes in redox potential and dehydrogenase activity in the soil. The results showed as follows: (1) The specific surface area of peanut shell biochar loaded with nano-zero-valent iron was large, and the nano-zero-valent iron particles were evenly distributed on the peanut shell biochar; (2) peanut shell BC/nZVI had a good degradation effect on α-HCH and γ-HCH in water, with degradation rates of 64.18% for α-HCH and 91.87% for γ-HCH in 24 h; (3) peanut shell BC/nZVI also had a good degradation effect on α-HCH and γ-HCH in soil, and the degradation rates of α-HCH and γ-HCH in the 1% BC/nZVI reached 55.2% and 85.4%, second only to 1% zero-valent iron. The degradation rate was the fastest from 0 to 7 days, while the soil oxidation-reduction potential (ORP) increased sharply. (4) The addition of BC/nZVI to the soil resulted in a significant increase in dehydrogenase activity, which further promoted the degradation of HCHs; the amount of HCHs degradation was significantly negatively correlated with dehydrogenase activity. This study provides a remediation strategy for HCH-contaminated sites, reducing the human health risk of HCHs in the soil while helping to improve the soil and increase the activity of soil microorganisms.

Identification of key genes in hepatocellular carcinoma associated with exposure to TCDD and α-endosulfan by WGCNA

2,3,7,8-tet-rachlorodibenzo-p-dioxin (TCDD) and α-endosulfan are two typical persistent organic pollutants (POPs), both of which accumulate in the liver and have potential carcinogenic hepatic effects. The underlying molecular mechanisms of pathogenesis of hepatocellular carcinoma (HCC) remain elusive when exposure to POPs. The aim of this study is to explore the key genes involved in HCC when exposure to TCDD and α-endosulfan by weighted gene co-expression network analysis (WGCNA). First, we performed co-expressed analysis on HCC and normal condition, based on WGCNA. In results, seven co-expressed modules were identified from 56 human liver samples, and the brown module correlated with five stages of HCC. Subsequently, we predicted that human five liver diseases were associated with exposure to TCDD and/or α-endosulfan by Nextbio analysis. Functional enrichment analysis showed that the brown module enriched in oxidation-reduction process, DNA replication, oxidoreductase activity and aging, which were the same as the results when exposure to the mixture of TCDD and α-endosulfan. Lastly, based on the protein-protein interaction network, we identified three novel genes including HK2, EXO1 and PFKP as key genes in HCC associated with exposure to TCDD and α-endosulfan mixture. In addition, survival analysis of key genes in Kaplan-Meier plotter demonstrated that aberrant expression levels of all the three key genes were associated with poor prognosis of HCC. Finally, Western blot analysis confirmed that protein expression levels of PFKP and HK2 in the three exposed groups were significantly elevated, while EXO1 were significantly upregulated when exposure to TCDD and α-endosulfan mixture in HepaRG cells. This study provides a new perspective to the understanding of the genetic mechanism of HCC when exposure to POPs.

Pollution Characteristics and Risk Assessment of Typical Antibiotics and Persistent Organic Pollutants in Reservoir Water Sources

The major task of Chinese water governance has gradually shifted away from water environment protection to water ecology remediation, and the governance of trace organic pollutants, including persistent organic pollutants and antibiotics, has attracted growing concern. The present study examined the seasonal distribution and sources of typical persistent organic pollutants and antibiotics in six representative water sources in the lower reaches of the Yangtze River, as well as their ecological risk to the environment. Six representative surface water and surface sediment samples were collected at different time intervals, i.e., December 2018, March 2019, and June 2019, and the concentrations of nineteen organochlorine pesticides (OCPs), seventeen polychlorinated biphenyls (PCBs), and eight polybrominated diphenyl ethers (PBDEs) were analyzed by GC-MS. The major findings are listed below: ① Endosulfan sulfate, Beta-endosulfan, and methoxychlor were the major persistent organic pollutants (POPs) detected in the sediments from Gaoyou Lake, Gonghu Lake, and Gehu Lake, with concentrations ranging from 9.0 to 10.6 ng/g. ② The target antibiotics in water sources were at relatively low levels. Occurrences of sulfonamide antibiotics in water and surface sediments were NF~37.4 ng·L−1 and NF~47.3 ng·g−1. Concentrations of quinolone antibiotics in the two media were NF~5.3 ng·L−1, 0.4~32.5 ng·g−1. ③ The combined toxicity of antibiotics (risk quotient, RQ) in Lake Gehu was 0.18, which was at a moderate risk level. There was no obvious ecological risk in most water sources affected by POPs. However, there were certain ecological risks in the water sources of Gaoyou Lake, Gonghu Lake, and Sanjiangying, induced by OCPs and PCBs. This study provides a scientific basis for the treatment of antibiotics and organic pollutants in reservoir water sources.

Sewage discharge and organic matter affect the partitioning behaviors of different polycyclic aromatic hydrocarbons in a river surface sediment-pore water system

The partitioning behaviors of persistent organic pollutants (POPs) between sediments and water are significant for their transport and fate in aquatic environments; however, an in-depth understanding is still required. Herein, we studied partitioning coefficients, fugacity fractions (ff), and influencing factors of parent, nitrated, and oxygenated polycyclic aromatic hydrocarbons (PPAHs, NPAHs, and OPAHs, respectively), which are typical POPs composed of multiple aromatic rings, in the surface sediment-pore water system of the Haihe River. The logarithmic organic carbon normalized partitioning coefficient (lgKOC) of PPAHs (4.04 ± 0.80) was evidently greater than those of NPAHs (2.64 ± 1.30) and OPAHs (2.69 ± 0.77). Owing to the effects of the polar groups in NPAHs and OPAHs, their partitioning behaviors were different from that of PPAHs. ff values showed that most PAH species approached dynamic equilibrium. As an important source of riverine PAHs, sewage discharge affected PAHs partitioning, whereas dam interception exerted less impact in this study. lgKOC and ff were negatively correlated with sediment organic matter, represented by particulate organic carbon (POC) and n-alkanes, and positively correlated with the sand fraction in surface sediments. In addition, positive correlations of lgKOC and ff with pH and salinity were observed in pore waters. The results indicate appreciable impacts of sewage discharge and organic matter on the partitioning processes of different PAHs.