Di-n-butyl phthalate stress induces changes in the core bacterial community associated with nitrogen conversion during agricultural waste composting

Nitrogen (N) loss during composting reduces the quality of compost products and causes secondary environmental pollution. Phthalate esters (PAEs) are common pollutants in agricultural wastes. However, little information is currently available on how PAEs affect N conversion during agricultural waste composting. This research systematically analyzed the impact of di-n-butyl phthalate (DBP) pollution on the N conversion and its related microbial community during composting. Our results indicated that DBP stress results in a shorter thermophilic phase, and then slower compost maturation during composting. Notably, DBP stress inhibited the conversion of ammonia to nitrate, but increased the release of NH₃ and N₂O leading to an increased N loss and an elevated greenhouse effect. Furthermore, DBP exposure led to a reduction of bacteria related to NH₄⁺ and NO₃^- conversion and altered the network complexity of the bacterial community involved in N conversion. It also reduced the abundance of a major nitrification gene (amoA) (P < 0.01) and increased the abundance of denitrification genes (nirK and norB) (P < 0.05). Moreover, DBP affected the overall microbial community composition at all tested concentrations. These findings provide theoretical and methodological basis for improving the quality of PAE-contaminated agricultural waste compost products and reducing secondary environmental pollution.

Distribution, Source Apportionment and Risk Assessment of Phthalate Esters in the Overlying Water of Baiyang Lake, China

As a kind of endocrine disruptor compounds, the presence of phthalate esters (PAEs) has become a global concern. In this study, the pollution levels and spatial distribution of sixteen PAEs were investigated. Their potential sources and eco-environmental health risk were discussed in Baiyang Lake and its upstream rivers during different periods. PAEs were detected in all of samples, ranging from 1215 to 3014 ng·L-1 in October 2020 and 1384 to 3399 ng·L-1 in May 2021. Dibutyl phthalate (DBP) and di-isobutyl phthalate (DIBP) were the predominant monomers, with a detection rate of 100% and the highest concentrations in the overlying water. Restricted by multiple factors, the spatial distribution difference between Baiyang Lake and its upstream rivers in October was more significant than in May. The source apportionment revealed that agricultural cultivation and disorderly use and disposal of plastic products were the primary factors for the contamination. The human health risk assessment indicated that eight PAE congeners did not pose significant carcinogenic and non-carcinogenic harms to males, females and children. However, the ecological risks of DBP, DIBP and di (2-ethylhexyl) phthalate to algae, crustaceans and fish species were moderate or high-risk levels. This study provides an appropriate dataset for the assessment of the pollution of PEs to the water ecosystem affected by anthropogenic activities.

Maternal urine phthalate metabolite exposure and miscarriage risk: a nested case-control study of the Zunyi Birth Cohort

Phthalates (PAEs) are widespread persistent organic pollutants and endocrine disruptors. However, the associations between PAE exposure and the risk of miscarriage in humans are unclear, and an insufficient number of studies have evaluated the possible threshold or dose-dependent effects of first trimester PAE exposure on miscarriage risk. Our research measured the levels of mono-methyl phthalate (MMP), mono-ethyl phthalate, mono-isobutyl phthalate, MiBP mono-butyl phthalate (MBP), mono-octyl phthalate, mono-benzyl phthalate, mono(2-ethylhexyl) phthalate, mono(2-ethyl-5-oxohexyl) phthalate, and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) in maternal urine collected in early gestation between 150 pregnancies ending in miscarriage and 150 pregnancies with live birth. We also estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for miscarriage and each PAE as a continuous variable or quartile. A restrictive cubic splines was used to assess dose-dependent effects after controlling for maternal characteristics (e.g., age, educational level). we identified monotonically increasing dose-dependent effects of MEHHP and MMP on the risk of miscarriage. The largest effect estimates were approximately threefold higher for the highest MBP (OR = 2.57; 95% CI = 1.32-5.01) or MMP quartile (OR = 3.57; 95% CI = 1.82-7.00) and two-fold higher for the highest MEHHP quartile (OR = 2.12; 95% CI = 1.10-4.11). Our research preliminarily obtained possible thresholds of MBP, MEHHP, and MMP which were 18.07, 2.38, and 0.80 µg/g Cr for the risk of miscarriage, respectively. First-trimester exposure to MBP, MEHHP, and MMP exceeding certain thresholds increases the risk of miscarriage.

Degradation of dibutyl phthalate by ozonation in the ultrasonic cavitation-rotational flow interaction coupled-field: performance and mechanism

Dibutyl phthalate (DBP) is present in hydraulic fracturing flowback and produced water. Degradation of DBP in aqueous by means of ozonation in ultrasonic cavitation-rotational flow interaction coupled-field (UC-RF coupled-field) was studied. The effect of ozone dosage, ozone intake flow, operating temperature, initial pH, DBP initial concentration, liquid flow rate, and ultrasonic power on the DBP removal was investigated. Results indicated that the DBP degradation rate was strongly influenced by the liquid flow rate and the ultrasonic power over the range investigated. HCO₃^- and Cl^- revealed an inhibitory effect on the DBP removal. SO₄^2- seemed to have no effect on DBP removal. The ozone utilization efficiencies in the UC-RF coupled-field were 2.77 and 1.13 times higher than those in the conventional microporous aeration (CMA) and rotating-flow microbubble aeration (RFMA), respectively. The DBP degradation rate was diminished in the presence of tert-butyl alcohol. Cavitation bubbles are considered as innumerable microreactors. Degradation of DBP by direct ozonation, hydroxyl radical (·OH) oxidation, high pressure, and high-temperature pyrolysis was demonstrated. Finally, a possible degradation pathway of DBP is obtained on the basis of the main reaction intermediates.

Phthalates impact on the epigenetic factors contributed specifically by the father at fertilization

BACKGROUND

Preconception exposure to phthalates such as the anti-androgenic dibutyl-phthalate (DBP) impacts both male and female reproduction, yet how this occurs largely remains unknown. Previously we defined a series of RNAs expressly provided by sperm at fertilization and separately, and in parallel, those that responded to high DBP exposure. Utilizing both populations of RNAs, we now begin to unravel the impact of high-DBP exposure on those RNAs specifically delivered by the father.

RESULTS

Enrichment of RNAs altered by DBP exposure within the Molecular Signature Database highlighted cellular stress, cell cycle, apoptosis, DNA damage response, and gene regulation pathways. Overlap within each of these five pathways identified those RNAs that were specifically (≥ fivefold enriched) or primarily (≥ twofold enriched) provided as part of the paternal contribution compared to the oocyte at fertilization. Key RNAs consistently altered by DBP, including CAMTA2 and PSME4, were delivered by sperm reflective of these pathways. The majority (64/103) of overlapping enriched gene sets were related to gene regulation. Many of these RNAs (45 RNAs) corresponded to key interconnected CRREWs (Chromatin remodeler cofactors, RNA interactors, Readers, Erasers, and Writers). Modeling suggests that CUL2, PHF10, and SMARCC1 may coordinate and mechanistically modulate the phthalate response.

CONCLUSIONS

Mediated through a CRREW regulatory network, the cell responded to exposure presenting stressed-induced changes in the cell cycle-DNA damage-apoptosis. Interestingly, the majority of these DBP-responsive epigenetic mediators' direct acetylation or deacetylation, impacting the sperm's cargo delivered at fertilization and that of the embryo.

Simplified Unified BARGE Method to Assess Migration of Phthalate Esters in Ingested PVC Consumer Products

The unified bioaccessibility research group of Europe (BARGE) method (UBM) suggests using in vitro experimental conditions for simulating the release of chemicals from confined matrices, such as soils and sediments, in the human gastrointestinal tract. It contains comprehensive steps that simulate human digestion pathways and has good potential for application in the leaching of plastic additives from accidentally ingested plastic particles. However, its complexity could be a challenge for routine screening assessments of the migration of chemicals from consumer plastic products. In this study, the UBM was modified to assess the migration of plastic additives from consumer products with five model phthalate esters (i.e., dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DNOP)) from polyvinyl chloride (PVC). The migration of phthalate esters was observed in four digestive phases (saliva, gastric, duodenal, and bile). Three separate experiments were conducted with the addition of (1) inorganic constituents only, (2) inorganic and organic constituents, and (3) inorganic and organic constituents in combination with digestive enzymes. While using enzymes with the UBM solution, the migrated mass for leached compounds was comparatively low (0.226 ± 0.04 μg) in most digestion phases, likely due to a self-generated coating of enzymes on the plastic materials. However, higher mass migration (0.301 ± 0.05) was observed when phthalate esters were analyzed in the UBM solution, excluding the enzymes. A ring test among six independent laboratories confirmed the robustness of the modified method. Therefore, we propose a simplified version of the original UBM designed mainly for the migration of inorganic elements using only the inorganic and organic components of the solution throughout all phases of digestion.

First Data on PAE Levels in Surface Water in Lakes of the Eastern Coast of Baikal

The increasing consumption of phthalates (PAEs), along with their high toxicity and high mobility, poses a threat to the environment. This study presents initial data on the contents of six priority PAEs in the water of lakes located on the eastern shore of Lake Baikal-Arangatui, Bormashevoe, Dukhovoe, Kotokel, and Shchuchye. The mean total concentrations of the six PAEs in lakes Arangatui and Bormashevoe (low anthropogenic load) were comparable to those in Kotokel (medium anthropogenic load, 17.34 µg/L) but were significantly higher (p < 0.05) than in Dukhovoe and Shchuchye (high anthropogenic load, 10.49 and 2.30 µg/L, respectively). DBP and DEHP were the main PAEs in all samples. The DEHP content in lakes Arangatui and Bormashevoe was quite high, and at some sampling sites it exceeded the MACs established by Russian, U.S. EPA, and WHO regulations. The assessment showed that there is no potential risk to humans associated with the presence of PAEs in drinking water. However, the levels of DEHP, DBP, and DnOP in the water pose a potential threat to sensitive aquatic organisms, as shown by the calculated risk quotients (RQs). It is assumed that the origin of the phthalates in the studied lakes is both anthropogenic and biogenic.

Occurrences and potential lipid-disrupting effects of phthalate metabolites in humpback dolphins from the South China Sea

Phthalate esters (PAEs) are ubiquitous environmental contaminants, arising growing public concern. Nevertheless, information on the exposure and risks of PAEs in wildlife remains limited. Here, we conducted the first investigation of the occurrences, spatiotemporal trends, and potential risks of twelve metabolites of PAEs (mPAEs) in 74 humpback dolphins from the northern South China Sea during 2005-2020. All twelve mPAEs (∑₁₂mPAEs: 9.6-810.7 ng g^-1 wet weight) were detected in the dolphin liver, and seven major mPAEs showed increasing trends during the study period, indicating high PAE contamination in the coastal environment of South China. Monoethylhexyl phthalate accounted for over half of the ∑₁₂mPAE concentrations. The accumulation of mPAEs in the dolphins was neither age-dependent nor sex-specific. Compared to parent PAEs, mPAEs generally induced higher agonistic effects on the dolphin peroxisome proliferator-activated receptor alpha/gamma (PPARA/G) as master regulators of lipid homeostasis. Although short-term in vitro assays revealed no significant activation of dolphin PPARA/G by tissue-relevant doses of mPAEs, long-term in vivo evidence (i.e., correlations between hepatic mPAEs and blubber fatty acids) suggested that chronic exposure to mPAEs might have impacted lipid metabolism in the dolphin. This study highlighted the potential health risks of PAE exposure on marine mammals.

Recognition and quantitative analysis for six phthalate esters (PAEs) through functionalized ZIF-67@Ag nanowires as surface-enhanced Raman scattering substrate

A novel surface enhanced Raman scattering (SERS) method was developed based on Ag nanowires embedded into functionalized metal-organic framework ZIF-67 (ZIF-67@Ag NWs) composite as substrate, which was applied for rapid recognition and sensitive detection of six PAEs. The Raman signals for PAEs detection were gained at ZIF-67@Ag NWs substrate mainly due to the "sharp tip effect" of rough Ag nanowires and excellent absorptive capacity of ZIF-67 to capture targeted molecules into the electromagnetic field. Different structural PAEs, including carbon chain lengths, isomers, and substituents, were evaluated for SERS performance and characteristic peaks under the optimal conditions. The SERS spectra proved that different PAEs exhibited some typically characteristic peaks in favor of recognizing and distinguishing them. The ZIF-67@Ag NWs as SERS substrate was successfully applied to detect six PAEs and exhibited wide linear ranges, low detection limit (LOD), excellent repeatability and stability (such as dibutyl phthalate DBP: linear range of 10^-2 ∼ 10^-12 mol/L, LOD 3 × 10^-13 mol/L). The ZIF-67@Ag NWs substrate by SERS was implemented to determine trace DBP in plastics with satisfactory recoveries of 82.5 % ∼ 108.3 %. The proposed ZIF-67@Ag NWs substrate may provide an effective and promising SERS platform for recognition and quantitative determination of different structural PAEs in environment.

Major biotransformation of phthalic acid esters in Eisenia fetida: Mechanistic insights and association with catalytic enzymes and intestinal symbionts

Phthalic acid esters (PAEs) are an important group of organic pollutants that are widely used as plasticizers in the environment. The PAEs in soil organisms are likely to be biotransformed into a variety of metabolites, and the combined toxicity of PAEs and their metabolites might be more serious than PAEs alone. However, there are only a few studies on PAE biotransformation by terrestrial animals, e.g. earthworms. Herein, the key biotransformation pathways of PAEs and their association with catalytic enzymes and intestinal symbionts in earthworms were studied using in vivo and in vitro incubation approaches. The widely distributed PAE in soil, dibutyl phthalate (DBP), was proven to be biotransformed rapidly together with apparent bioaccumulation in earthworms. The biotransformation of PAE congeners with medium or long side chains appeared to be faster compared with those with short side chains. DBP was biotransformed into butyl methyl phthalate (BMP), monobutyl phthalate (MBP), and phthalic acid (PA) through esterolysis and transesterification. Besides, the generation of small quantities of low-molecular weight metabolites via β-oxidation, decarboxylation or ring-cleavage, was also observed, especially when the appropriate proportion of NADPH coenzyme was applied to transfer electrons for oxidases. Interestingly, the esterolysis of PAEs was mainly regulated by the cytoplasmic carboxylesterase (CarE) in earthworms, with a Michaelis constant (K_m) of 0.416 mM in the catalysis of DBP. The stronger esterolysis in non-intestinal tissues indicated that the CarE was primarily secreted by non-intestinal tissues of earthworms. Additionally, the intestinal symbiotic bacteria of earthworms could respond to PAE stress, leading to the changes in their diversity and composition. The enrichment of some genera e.g. Bacillus and Paracoccus, and the enhancement of metabolism function, e.g. amino acids, energy, lipids biosynthesis and oxidase secretion, indicated their important role in the degradation of PAEs.

Cord blood immune profile: Associations with higher prenatal plastic chemical levels

Prenatal exposure to plastic chemicals has been associated with alterations to early-life immune function in children. However, previous studies have generally been small and focused on limited repertoires of immune indices. In a large population-based pre-birth cohort (n = 1074), third-trimester measurements of eight phthalate metabolites and three analogues of bisphenols were used to estimate prenatal exposure to phthalate and bisphenol compounds. In cord blood, immune cell populations were measured by flow cytometry and an extensive panel of cytokines and chemokines were measured by multiplex immunoassay. We used these cord blood analytes to estimate "early life" immune profiles. The full study sample comprises data from 774 infants with prenatal plastic metabolite measurements and any cord blood immune data. Multiple linear regression analysis was used to evaluate whether prenatal phthalate and bisphenol exposure was prospectively associated with cord blood immune cell populations and cytokine and chemokine levels. Generally, inverse associations were observed between prenatal phthalate exposure and cord blood immune indices. Higher exposure to di-n-butyl phthalate was associated with lower cord blood levels of platelet-derived growth factor (PDGF) and interferon gamma-induced protein 10 (IP-10); higher exposure to the sum of dibutyl phthalates was associated with lower cord blood levels of IP-10; and higher exposure to benzyl butyl phthalate was associated with lower cord blood levels of interleukin 1 beta (IL-1β). There was less evidence of associations between bisphenols and cord blood immune indices. These results extend previous work examining prenatal plastic chemical exposure and early-life immune development and highlight the importance of further examination of potential associations with health-related outcomes.

Co-occurrence of light microplastics and phthalate esters in soils of China

The terrestrial environment is both a critical source and sink for microplastics (MPs). However, further efforts into the risk assessment, management, and mitigation activities of MPs in the terrestrial environment were limited by the scant data on their occurrence. In this study, we investigated the co-occurrence and correlations of light MPs and phthalate esters (PAEs) in the soils of China's hotspots and non-hotspot regions. Light MPs and PAEs were detected in all agricultural and urban soils (n = 125). In soils from hotspots (Shihezi, Xinjiang) where intense plastic mulching was used, the concentrations of MPs and phthalate diesters (di-PAEs) were 650-36,450 pcs kg^-1 and 55.60-1236.64 μg kg^-1, respectively. In hotspots but not in non-hotspot regions of China, a positive correlation between MPs and PAEs was established, suggesting PAEs may serve as an indicator of MP contamination in hotspots. High quantities of MPs (1143-5911 pcs kg^-1) and PAEs (67.3-1236.64 μg kg^-1) were also detected in urban park soils, demonstrating a need for future research on MP in urban soils. In addition, the ubiquitous co-occurrence of MPs and PAEs in all 125 investigated soils revealed that potential joint toxicity, co-transformation, and co-transportation of MPs and PAEs should not be disregarded.

Human exposure to phthalate esters in soils embodied in interregional food trade in China

The ubiquitous occurrence of phthalate esters (PAEs) in agricultural soil results in their inevitable accumulation in crops, potentially increasing the risk of human exposure to PAEs via daily food intake. Dietary health risk of PAEs not only depends on locally produced food but also the imported food from other regions. However, the impact of interregional food trade on human dietary exposure to PAEs has been seldom assessed. Herein, we investigated the impact of interregional food trade on the dietary exposure to PAEs that contributed from soil contamination in China. The average daily dietary intake of PAEs for the Chinese general population was 24.3 μg/kg/day when assuming the total consumption of crops from local market only, while the average daily dietary intake of PAEs for the Chinese general population was decreased by 2.9% when the effects of interregional food trade were involved into the calculation. Additionally, the interregional food trade remarkably increased the daily dietary intake of PAEs in the regions of Beijing-Tianjin region (47.8%), North (21.4%) and Central (4.26%). As a result, the hazard quotient value of PAEs in the regions of Beijing-Tianjin region, North and Central increased by 29.4%, 11.0% and 5.0%, respectively, owing to the consumption of imported crops from the highly PAEs contaminated regions. In contrast, the daily intake and hazard quotient value of PAEs in the regions of Central Coast, Northwest, Northeast and South Coast decreased due to the interregional trade. These results indicated that the interregional food trade promoted the transfer of PAEs between regions and thus altered the potential risk to the local population. Overall, this study highlights the importance of taking the interregional food trade into account to provide a more accurate risk assessment of dietary exposure to pollutants.

Estimated daily intake of phthalates, parabens, and bisphenol A in hospitalised very low birth weight infants

Very low birth weight infants (VLBW, birth weight (BW) < 1500 g) are exposed to phthalates, parabens and bisphenol A (BPA) early in life. We estimated daily intake (EDI) of these excipients in 40 VLBW infants the first and fifth week of life while hospitalised. Based on urinary samples collected in 2010, EDI was calculated and compared to the tolerable daily intake (TDI) with hazard quotients (HQs) evaluated. A HQ > 1 indicates that EDI exceeded TDI with increased risk of adverse health effects. EDI was higher in VLBW infants compared to term-born infants and older children. VLBW infants born at earlier gestational age (GA), or with lower BW, had higher EDI than infants born at later GA or with higher BW. First week median EDI for BPA was higher than TDI in 100% of infants, in 75% for di(2-ethylhexyl) phthalate (DEHP), 90% for the sum of butyl benzyl phthalate (BBzP), di-n-butyl phthalate (DnBP), DEHP and di-iso-nonyl phthalate (DiNP) = ∑BBzP+DnBP+DEHP+DiNP, and in 50% of infants for propylparaben (PrPa), indicating increased risk of adverse effects. Fifth week EDI remained higher than TDI in all infants for BPA, in 75% for DEHP and ∑BBzP+DnBP+DEHP+DiNP, and 25% of infants for PrPa, indicating prolonged risk. Maximum EDI for di-iso-butyl phthalate was higher than TDI suggesting risk of adverse effects at maximum exposure. VLBW infants born earlier than 28 weeks GA had higher EDI, above TDI, for PrPa compared to infants born later than 28 weeks GA. Infants with late-onset septicaemia (LOS) had higher EDI for DEHP, ∑BBzP+DnBP+DEHP+DiNP and BPA, above TDI, compared to infants without LOS. More 75% of the infants' EDI for DEHP and ∑BBzP+DnBP+DEHP+DiNP, 25% for PrPa, and 100% of infants' EDI for BPA, were above TDI resulting in HQs > 1, indicating increased risk of adverse health effects.

Impacts of dibutyl phthalate on biological municipal wastewater treatment in a pilot-scale A2/O-MBR system

Dibutyl phthalate (DBP) is a typical contaminant in pharmaceutical wastewater with strong bio-depressive properties which potentially affects the operation of municipal wastewater treatment systems. Based on a year-round monitoring of the quality of influent and effluent of a full-scale pharmaceutical wastewater treatment plant in Northeast China, the DBP was found to be the representative pollutant and its concentration in the effluent ranged 4.28 ± 0.93 mg/L. In this study, the negative effects of DBP on a pilot-scale A²/O-MBR system was investigated. When the influent DBP concentration reached 8.0 mg/L, the removals of chemical oxygen demand (COD) and total nitrogen (TN) were significantly inhabited (P < 0.01), with the effluent concentration of 54.7 ± 2.6 mg/L and 22.8 ± 3.7 mg/L, respectively. The analysis of pollutant removal characteristics of each process unit showed that DBP had the most significant effects on the removals of COD and TN in the anoxic tank. The α- and β-diversity in the system decreased significantly when the influent DBP concentration reached 8.0 mg/L. The impacts of DBP on known nitrifying bacteria, such as Nitrospira, and phosphorus accumulating organisms (PAOs), such as Cadidatus Accumulibacter, were not remarkable. Whereas, DBP negatively affected the proliferation of key denitrifying bacteria, represented by Simplicispira, Dechloromonas and Acinetobacter. This study systematically revealed the impacts of DBP on the pollutants removal performance and the bacterial community structure of the biological municipal wastewater treatment process, which would provide insights for understanding the potential impacts of residues in treated pharmaceutical wastewater on biological municipal wastewater treatment.

Development and application of tricolor ratiometric fluorescence sensor based on molecularly imprinted nanoparticles for visual detection of dibutyl phthalate in seawater and fish samples

A tricolor ratiometric fluorescence sensor was fabricated by mixing blue- and red-emission molecularly imprinted quantum dots (MIP-QDs) with green-emission quantum dots at the optimal ratio. The MIP-QDs were synthesized by coating CdSe/ZnS QDs in polymer by inverse microemulsion method. Compared with single-emission or dual-emission sensors, the tricolor ratiometric fluorescence sensor provided a wider range of color variations for visual DBP detection. The ratio fluorescence value I₅₃₀/(I₄₅₀ + I₆₃₀) of the tricolor ratiometric fluorescence sensor linearly changed within the concentration of 2.0-20.0 × 10³ μg/L DBP. The correlation coefficient was 0.9910, and the limits of detection were 1.0 μg/kg and 0.65 μg/L in fish and seawater, respectively. Meanwhile, the fluorescence color gradually changed from purple to plum to pink to salmon to yellowish green and finally to green. The recoveries of DBP in fish and seawater were 84.3 %-91.4 % and 88.3 %-110.3 %, respectively. Moreover, no obvious differences were observed between the detection results of the tricolor ratiometric fluorescence sensor and gas chromatography-tandem mass spectrometry. The tricolor ratiometric fluorescence sensor constructed herein provides an ideal choice for rapid and intuitive DBP detection in environmental and aquatic products.

Analysis of the performance of the efficient di-(2-ethylhexyl) phthalate-degrading bacterium Rhodococcus pyridinovorans DNHP-S2 and associated catabolic pathways

The widespread use of plastic has led to the global occurrence of phthalate esters (PAEs) pollution. PAEs can be effectively removed from polluted environments by microbe-mediated degradation. Di-(2-ethylhexyl) phthalate (DEHP) has the highest residual concentration in agricultural soil-contaminated areas compared to other PAEs in most of China. The Rhodococcus pyridinovorans DNHP-S2 microbial isolate identified was found to efficiently degrade DEHP. Within a 72 h period, the bacteria were able to degrade 52.47% and 99.75% of 500 mg L^-1 DEHP at 10 °C and 35 °C, respectively. Dimethyl phthalate (DMP) was first identified as an intermediate metabolite of DEHP, which is different from the previously reported DEHP catabolic pathway. Genomic sequencing of DNHP-S2 identified benzoate 1,2-dioxygenase and catechol 2,3/1,2-dioxygenase as potential mediators of DEHP degradation, consistent with the existence of two downstream metabolic pathways governing DEHP degradation. Three targets DEHP metabolism-related enzymes were found to be DEHP-inducible at the mRNA level, and DNHP-S2 was able to mediate the complete degradation of DEHP at lower temperatures, as confirmed via RT-qPCR. DNHP-S2 was also found to readily break down other PAEs including DMP, di-n-butyl phthalate (DBP), di-n-octyl phthalate (DnOP), and n-butyl benzyl phthalate (BBP). Together, these results thus highlight DNHP-S2 as a bacterial strain with great promise as a tool for the remediation of PAE pollution. In addition to providing new germplasm and genetic resources for use in the context of PAE degradation, these results also offer new insight into the potential mechanisms whereby PAEs undergo catabolic degradation, making them well-suited for use in PAE-contaminated environments.

Wide occurrence of seven phthalate plasticizers and two typical microplastics in pig feed

Plastics are widely used as packaging and engineering materials in feed processing, which leads to the potential contamination of plasticizers and microplastics (MPs) in animal feeds. In this study, the concentrations of two typical MPs, i.e., polyethylene terephthalate (PET) and polycarbonate (PC), and seven phthalates (PAEs) as well as their corresponding monoester metabolites (mPAEs) in 45 pig feed samples in China were analyzed by mass spectrometers. Among PAEs, dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) were detected in all samples, and DEHP showed the highest concentrations of 8.26-2464 μg/kg, which accounted for 65.6% of the total detected PAEs. PET MPs (<MDL-302 μg/kg) were detected in 97.8% of samples. Meanwhile, mPAEs were also detected in feed samples with high detection rates but of much lower concentrations. A significantly positive correlation was observed between DEHP and PET MPs. This indicates that the sources of DEHP and MPs in feeds are homologous, mainly from processing and packaging. Besides, the significantly positive correlations between DBP/DEHP and mBP/mEHP indicated the degradation of PAEs to mPAEs during feed production and transportation. The estimated daily intake (EDI) of PAEs and PET MPs were 2.40-70.3 and 0.800-7.79 μg/kg-bw-day, respectively. The results of this study provided new insight into the first evidence of the co-occurrence and risk of MPs, PAE, and mPAEs in pig feed.

Composting and green technologies for remediation of phthalate (PAE)-contaminated soil: Current status and future perspectives

Phthalate esters (PAEs) are hazardous organic compounds that are widely added to plastics to enhance their flexibility, temperature, and acidic tolerance. The increase in global consumption and the corresponding environmental pollution of PAEs has caused broad public concerns. As most PAEs accumulate in soil due to their high hydrophobicity, composting is a robust remediation technology for PAE-contaminated soil (efficiency 25%-100%), where microbial activity plays an important role. This review summarized the roles of the microbial community, biodegradation pathways, and specific enzymes involved in the PAE degradation. Also, other green technologies, including biochar adsorption, bioaugmentation, and phytoremediation, for PAE degradation were also presented, compared, and discussed. Composting combined with these technologies significantly enhanced removal efficiency; yet, the properties and roles of each bacterial strain in the degradation, upscaling, and economic feasibility should be clarified in future research.

Prioritization of micropollutants in municipal wastewater and the joint inhibitory effects of priority organic pollutants on Vibrio qinghaiensis sp.-Q67

Treatment of wastewater in municipal wastewater treatment plants has become a major barrier to organic pollutants entering the aquatic environment. In this study, qualitative screening of organic micropollutants was conducted in a typical municipal wastewater treatment plant (MWWTP) using gas chromatography-mass spectrometry (GC-MS). The identified compounds were prioritized according to their comprehensive scores ranked by detection frequency, semi-quantitative concentration, bioaccumulation, ecotoxicity, and biodegradability. The results showed dibutyl phthalate, antioxidant 2246, methyl stearate, 2,4,6-tri‑tert-butylphenol, and dioctyl phthalate had the top five scores and were ranked as priority organic pollutants in the municipal wastewater. The individual and joint toxicity determinations of the five compounds were carried out by a bioluminescence inhibition assay using Vibrio qinghaiensis sp.-Q67 (V. qinghaiensis). The individual toxicity assay results of these pollutants on V. qinghaiensis demonstrated that the order of the acute toxicity of the five priority organic pollutants was as follows: dioctyl phthalate> dibutyl phthalate> methyl stearate> antioxidant 2246> 2,4,6-tri‑tert-butylphenol. The joint toxicity showed partial addition or antagonism among these pollutants. The prediction results of the mixed toxicity were compared between the concentration addition model and the independent action model, indicating that a single traditional prediction model could not accurately predict the mixed toxicity of different types of organic pollutants, and that a comprehensive application of model prediction could improve the accuracy of mixed toxicity prediction. This method could provide a theoretical basis for systematic screening and toxicity prediction of pollutants in wastewater.

Fate of phthalates in a river receiving wastewater treatment plant effluent based on a multimedia model

Phthalic acid esters (PAEs) can enter environment media by secondary effluent discharge from wastewater treatment plants (WWTP) into receiving rivers, thus posing a threat to ecosystem health. A level III fugacity model was established to simulate the fate and transfer of four PAEs in a study area in Tianjin, China, and to evaluate the influence of WWTP discharge on PAEs levels in the receiving river. The results show that the logarithmic residuals of most simulated and measured values of PAEs are within one order of magnitude with a good agreement. PAEs in the study area were mainly distributed in soil and sediment phases, which accounted for 84.66%, 50.26%, 71.96% and 99.09% for dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), respectively. The upstream advection accounted for 77.90%, 93.20%, 90.21% and 90.93% of the total source of DMP, DEP, DBP and DEHP in the river water, respectively, while the contribution of secondary effluent discharge was much lower. Sensitivity analysis shows that emission and inflow parameters have greater influences on the multimedia distributions of PAEs than physicochemical and environmental parameters. Monte Carlo analysis quantifies the uncertainties and verifies the reliability of the simulation results.

Assessing microplastic ingestion and occurrence of bisphenols and phthalates in bivalves, fish and holothurians from a Mediterranean marine protected area

Microplastic (MP) ingestion, along with accumulated plasticizers such as bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS), and phthalates represented by diethyl phthalate (DEP), dibutyl phthalate (DBP) and bis (2-ethylhexyl) phthalate (DEHP), were quantified in bivalves, fish, and holothurians collected from a coastal pristine area at the western Mediterranean Sea. MP ingestion in sediment-feeders holothurians (mean value 12.67 ± 7.31 MPs/individual) was statistically higher than ingestion in bivalves and fish (mean 4.83 ± 5.35 and 3 ± 4.44 MPs/individual, respectively). The main ingested polymers were polyethylene, polypropylene, and polystyrene. The levels of BPS, BPF, and DEHP were highest in bivalves' soft tissue; BPA and DBP had the highest levels in the holothurians' muscle. In addition, the levels of all plasticizers assessed were lowest in fish muscle; only BPA levels in fish were higher than in bivalves, with intermediate values between those of bivalves and holothurians. This study provides data on exposure to MPs and plasticizers of different species inhabiting Cabrera Marine Protected Area (MPA) and highlights the differences in MP ingestion and levels of plasticizers between species with different ecological characteristics and feeding strategies.

Using fluorescence and circular dichroism (CD) spectroscopy to investigate the interaction between di-n-butyl phthalate and bovine serum albumin

The interaction between di-n-butyl phthalate (DBP) and bovine serum albumin (BSA) in physiological Tris-HCl buffer at pH 7.4 was investigated by fluorescence quenching technique. By analyzing the fluorescence spectrum and intensity, it was observed that the DBP had a strong ability to quench the intrinsic fluorescence of BSA through a static quenching procedure. The binding constants K and the number of binding sites n of DBP with BSA were calculated to be 0.11 × 10² L·mol^-1 and 0.52 at 298 K, respectively. The thermodynamic parameters of enthalpy change (ΔH) and entropy change (ΔS) were also calculated to be positive showing that hydrophobic forces might play a major role in the binding of DBP to BSA. The binding process was spontaneous in which Gibbs free energy change (ΔG) was negative. The distance (r) between the donor (BSA) and acceptor (DBP) was calculated to be 2.02 nm based on Forster's non-radiative energy transfer theory, which indicated that the energy transfer from BSA to DBP occurs with a high possibility. The synchronous fluorescence, three-dimensional fluorescence, and circular dichroism (CD) spectra showed that the binding of di-n-butyl phthalate to BSA induced conformational changes in BSA. The interaction between DBP and BSA can help researchers better understand the nature of poisons and serve people in the right way with first aid and detoxification.

Occurrence and Risk Assessment of Personal PM2.5-Bound Phthalates Exposure for Adults in Hong Kong

We performed personal PM_2.5 monitoring involving 56 adult residents in Hong Kong. Additionally, paired personal and residential indoor fine particle (PM_2.5) samples were collected from 26 homes and from 3 fixed monitoring locations (i.e., outdoor samples). Six PM_2.5-bound phthalate esters (PAEs)-including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)-were measured using a thermal desorption-gas chromatography/mass spectrometer method. Average ∑₆PAEs (i.e., summation of six PAE congeners) concentrations in personal PM_2.5 exposure (699.4 ng/m³) were comparable with those in residential indoors (646.9 ng/m³), and both were slightly lower than the outdoor levels. DEHP was the most abundant PAE congener (80.3%-85.0%) and found at the highest levels in different exposure categories, followed by BBP, DnBP, and DnOP. Strong correlations were observed between DEHP with DnBP (r_s: 0.81-0.90; p < 0.01), BBP (r_s: 0.81-0.90; p < 0.01), and DnOP (r_s: 0.87-0.93; p < 0.01) in each exposure category. However, no apparent intercorrelations were shown for PAE congeners. Higher indoor concentrations and a stronger correlation between DMP and DEP were found compared with outdoor concentrations. Principal component analysis affirmed heterogeneous distribution and notable variations in PAE sources across different exposure categories. The average daily intakes of ∑₆PAEs and DEHP via inhalation were 0.14-0.17 and 0.12-0.16 μg/kg-day for adults in Hong Kong. A time-weighted model was used to estimate PAE exposures incorporating residential indoor and outdoor exposure and time activities. The inhalation cancer risks attributable to measured and estimated personal exposure to DEHP exceeded the U.S. EPA's benchmark (1 × 10^-6). The results provide critical information for mitigation strategies, suggesting that PAEs from both ambient and indoor sources should be considered when exploring the inhalation health risks of PAEs exposure.

Effect of plastic pollution on freshwater flora: A meta-analysis approach to elucidate the factors influencing plant growth and biochemical markers

The deterioration in the water quality of urban water bodies through plastic contamination is emerging as a matter of serious concern. Microplastics (MPs) and nanoplastics (NPs) both affect the growth and productivity of aquatic flora. However, there have been a lot of variations in the reported studies which calls for revisiting the results with an analytical approach. Therefore, this study was designed to systematically evaluate the publications based on PRISMA (2020) guidelines. In this connection, 43 eligible articles were selected for meta-analysis followed by subgroup analysis to determine the impact of size, concentration, plastic polymers, and effect of plant classes on several physiological and biochemical parameters (growth, chlorophyll-a, carotenoids, protein, and antioxidant enzymes). The results indicated that the higher concentrations of plastics negatively affected the growth, and also enhanced the protein content and antioxidative enzyme activity. While, NPs were found to impart an inhibitory effect on pigment contents, along with a significant increase in protein content and antioxidative enzyme activity. Among the plastic polymers, dibutyl phthalate (DBP) showed a comparatively higher effect on growth, whereas the photosynthetic pigments were disrupted to a greater extent in the presence of polyvinyl chloride (PVC) plastics. Moreover, the growth parameters under plastic exposure were affected in the algal members to a greater extent in comparison to the other plant groups. Lastly, several plants like Komvophoron, Elodea, Myriophyllum, Nostoc, Raphidocelis, Scenedesmus, Utricularia, Dunaliella, and Lemna appeared to be more tolerant than others (Tolerance Index ≥ 0.8), showing a significantly minimal effect on growth inhibition.