Di-n-butyl Phthalate Concentration Research Articles

Mechanistic screening of reproductive toxicity in a novel 3D testicular co-culture model shows significant impairments following exposure to low-dibutyl phthalate concentrations

To improve the mechanistic screening of reproductive toxicants in chemical-risk assessment and drug development, we have developed a three-dimensional (3D) heterogenous testicular co-culture model from neonatal mice. Di-n-butyl phthalate (DBP), an environmental contaminant that can affect reproductive health negatively, was used as a model compound to illustrate the utility of the in vitro model. The cells were treated with DBP (1 nM to 100 µM) for 7 days. Automated high-content imaging confirmed the presence of cell-specific markers of Leydig cells (CYP11A1 +), Sertoli cells (SOX9 +), and germ cells (DAZL +). Steroidogenic activity of Leydig cells was demonstrated by analyzing testosterone levels in the culture medium. DBP induced a concentration-dependent reduction in testosterone levels and decreased the number of Leydig cells compared to vehicle control. The levels of steroidogenic regulator StAR and the steroidogenic enzyme CYP11A1 were decreased already at the lowest DBP concentration (1 nM), demonstrating upstream effects in the testosterone biosynthesis pathway. Furthermore, exposure to 10 nM DBP decreased the levels of the germ cell-specific RNA binding protein DAZL, central for the spermatogenesis. The 3D model also captured the development of the Sertoli cell junction proteins, N-cadherin and Zonula occludens protein 1 (ZO-1), critical for the blood–testis barrier. However, DBP exposure did not significantly alter the cadherin and ZO-1 levels. Altogether, this 3D in vitro system models testicular cellular signaling and function, making it a powerful tool for mechanistic screening of developmental testicular toxicity. This can open a new avenue for high throughput screening of chemically-induced reproductive toxicity during sensitive developmental phases.

Effects of D-allulose on di (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP)-induced toxicity in rats

Background: Oral exposure to high concentrations of DEHP and DBP causes testicular and hepatotoxicity in rodents. Phthalate metabolites such as mono (2-ethylhexyl) phthalate (MEHP) and mono-n-butyl phthalate (MBP) stimulate peroxisome proliferator-activated receptors and disrupts carbohydrate and lipid metabolism. The oxidative stress generated may be closely related to these toxicities. Method: To clarify the effects of the rare sugar D-allulose, a potent free radical scavenger, on testicular and hepatotoxicity induced by DEHP and DBP, rats were fed DEHP or DBP containing diet and D-allulose water. Result: Dietary exposure to DEHP and DBP induced a significant decrease in testicular weight and significant increase in liver weight. D-allulose treatment significantly inhibited the testicular weight loss. But D-allulose treatment did not significantly suppress the increase in liver weight. Plasma glucose levels were significantly lower in the DEHP- or DBP-only treated groups compared to controls, but were improved by D-allulose treatment. This suggests that D-allulose blocks DEHP- and DBP-induced glycemic suppression. Plasma lipid-related markers such as total cholesterol, high-density lipoprotein cholesterol, and triglycerides were lower than controls in all treatment groups on the DEHP and DBP diets, but showed a slight trend toward improvement with D-allulose. Conclusion: D-allulose reduced DEHP- and DBP-induced testicular toxicity and blood glucose suppression in rats, but did not improve liver hypertrophy. This effect may be due to the strong oxidant scavenging ability of D-allulose.

Effects of pH and Temperature on the Leaching of Di(2-Ethylhexyl) Phthalate and Di-n-butyl Phthalate from Microplastics in Simulated Marine Environment

This study aims to examine the influences of pH and temperature on the leaching of bis(2-ethylhexyl) (DEHP) and di-n-butyl phthalate (DBP) from microplastics in pseudo-seawater. This study consisted of two parts. In the first part, DEHP and DBP in three common microplastics (polyethylene (PE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC)) were experimentally leached into pseudo-seawater at pH values of 5, 7, and 9 respectively with simulated waves. High-performance liquid chromatography was used to detect the leached DBP and DEHP in the samples. The concentrations of DBP leached from PE, PVC and PET from Day-4 to Day-16 were in the ranges of 0.558 – 0.711 mg/L, 0.518 – 0.760 mg/L and 0.540 – 0.791 mg/L respectively. The effect of pH on the amount of DBP leached could not be concluded with different polymers having different optimal pH of leaching. In the second part, DEHP and DBP in six common microplastics (PE, PET, PVC, plastic wrap, disposable gloves, disposable plastic bag) were leached into pseudo-seawater at 25℃ and 45℃. DBP and DEHP were not detected at 25°C, and a small amount of DBP was detected at 45°C. Higher temperatures promoted the leaching of DBP. This study provides important insight into the leaching behaviors of phthalates from microplastics in the marine environment, which is currently understudied.

Phthalate pollution and migration in soil-air-vegetable systems in typical plastic agricultural greenhouses in northwestern China

Phthalate pollution in plastic greenhouses (PGs) has aroused concerns. However, mechanisms and factors of vegetables planted in PGs (VPGs) accumulating phthalates from soil and air are unclear. To fill the gap, 19 PGs in Shaanxi, the largest vegetable production province in northwestern China, were selected to probe this issue. 35 soil samples, 48 air samples, and 26 VPG samples were collected in winter and summer. Medians of sum of 7 phthalate concentrations (∑7 PAEs) in PG soil, air, and VPGs were 73.9 μg kg−1, 5300 ng m−3, and 1053 μg kg−1 dry weight, respectively. ∑7 PAE concentrations in PG environmental media in winter were higher than summer, with the significant difference in VPGs. Sum concentrations of bis (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) accounted for 76.8% and 82.3% of the ∑7 PAEs in soil and VPGs. DnBP and DEHP concentrations in VPGs were significantly correlated to those in air and soil, with correlation coefficients (R) of 0.89 and 0.96 to air and 0.68 and 0.59 to soil. Log-transformed soil-air partition coefficient (log KSA) and fugacity fraction (log ff) of DnBP decreased while log KSA and log ff of DEHP increased from winter to summer, though DnBP in soil volatilized to air while DEHP in air sank to soil within the year. These issues were caused by air temperature changes and the application of plastic films. Furthermore, DnBP concentrations in VPGs were positively correlated to KSA values of DnBP (R = 0.87) while those of DEHP were negative (R = −0.82). Therefore, VPGs could uptake more phthalates from air than from soil, especially for edible parts of leafy and solanaceous VPGs. Applying phthalates free agricultural films and precision management such as adjusting air temperature in PGs could be considered to ensure VPG safeties.

Potential risk of BPA and phthalates in commercial water bottles: a minireview

The global water bottling market grows annually. Today, to ensure consumer safety, it is important to verify the possible migration of compounds from bottles into the water contained in them. Potential health risks due to the prevalence of bisphenol A (BPA) and phthalates (PAEs) exposure through water bottle consumption have become an important issue. BPA, benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) can cause adverse effects on human health. Papers of literature published in English, with BPA, BBP, DBP and DEHP detections during 2017, by 2019 by liquid chromatography and gas chromatography analysis methods were searched. The highest concentrations of BPA, BBP, DBP and DEHP in all the bottled waters studied were found to be 5.7, 12.11, 82.8 and 64.0 μg/L, respectively. DBP was the most compound detected and the main contributor by bottled water consumption with 23.7% of the Tolerable Daily Intake (TDI). Based on the risk assessment, BPA, BBP, DBP and DEHP in commercial water bottles do not pose a serious concern for humans. The average estrogen equivalent level revealed that BPA, BBP, DBP and DEHP in bottled waters may induce adverse estrogenic effects on human health.

Impact of microplastic addition on degradation of dibutyl phthalate in offshore sediments

In this work, effects of microplastics (polypropylene and polystyrene) at four concentrations (0.2–10%, w/w) on di-n-butyl phthalate (DBP) degradation in offshore sediments were investigated. DBP degradation percentage was enhanced by 0.2% microplastics (7.3–11.0% increment) but was reduced by 2–10% microplastics (3.7–27.7% decrement). Meanwhile, addition of microplastics with higher sorption ability to DBP led to lower DBP degradation percentage. The initial concentration of bioavailable DBP in sediments decreased with the increase of microplastic sorption ability to DBP and microplastic concentration. Microbial community structure was more significantly influenced by microplastic type than by microplastic concentration. Significant positive correlation was observed between the total relative abundances of dominant DBP-degraders and DBP degradation percentage. The results indicated that the changes in DBP degradation percentage were related to both DBP bioavailability and the total relative abundances of dominant DBP-degraders. Hence, persistence of the pollutant in the coastal environment was microplastic type- and concentration-dependent.

Impacts of Endocrine Disruptor di-n-Butyl Phthalate Ester on Microalga Chlorella vulgaris Verified by Approaches of Proteomics and Gene Ontology.

Di-n-butyl phthalate (DBP) is an extensively used plasticizer. Most investigations on DBP have been concentrated on its environmental distribution and toxicity to humans. However, information on the effects of plasticizers on algal species is scarce. This study verified the impacts of endocrine disruptor di-n-butyl phthalate ester on microalga Chlorella vulgaris by approaches of proteomics and gene ontology. The algal acute biotoxicity results showed that the 24h-EC50 of DBP for C. vulgaris was 4.95 mg L−1, which caused a decrease in the chlorophyll a content and an increase in the DBP concentration of C. vulgaris. Proteomic analysis led to the identification of 1257 C. vulgaris proteins. Sixty-one more proteins showed increased expression, compared to proteins with decreased expression. This result illustrates that exposure to DBP generally enhances protein expression in C. vulgaris. GO annotation showed that both acetolactate synthase (ALS) and GDP-L-fucose synthase 2 (GER2) decreased more than 1.5-fold after exposure to DBP. These effects could inhibit both the valine biosynthetic process and the nucleotide-sugar metabolic process in C. vulgaris. The results of this study demonstrate that DBP could inhibit growth and cause significant changes to the biosynthesis-relevant proteins in C. vulgaris.

Chronic exposure to di‐n‐butyl phthalate causes reproductive toxicity in zebrafish

Di-n-butyl phthalate (DBP) is known to have adverse effects on reproduction in mammals and is pervasive in the aquatic environment. The objective of the present study was to investigate whether long-term exposure to low concentrations of DBP can affect fish reproduction. In this study, zebrafish (Danio rerio) embryos (F0 ) were exposed to low concentrations (4.9, 13.6 and 43.8 μg/L) of DBP from 2 hours post-fertilization until sexual maturation. The results demonstrate that chronic exposure to DBP (43.8 μg/L) impaired the reproductive function of zebrafish, as verified by reduced egg production and modifications to gonadal histology of the treated fish. Plasma 17β-estradiol levels in female zebrafish decreased significantly in a concentration-dependent manner, while testosterone levels in males increased significantly when fish were exposed to 43.8 μg/L DBP. Real-time polymerase chain reaction was performed to examine selected genes in the hypothalamic-pituitary-gonadal (HPG) axis and liver. Hepatic vitellogenin gene transcription was downregulated in both males and females, suggesting that DBP possesses anti-estrogenic activity. The disturbed steroid hormones were accompanied by the significant alterations in gene expression along the HPG axis. Additionally, parental exposure to DBP caused reduced hatching and survival rate as well as decreased growth in the F1 generation. Taken together, these results demonstrate that long-term exposure to low concentrations of DBP in zebrafish could cause reproductive toxicity, implying that DBP could have significant adverse effects on fish populations, particularly in a highly DBP-contaminated aquatic environment.

Analysis on organic compounds in water leachate from biomass

Water washing on biomass can effectively remove K, Na and Cl, which will cause serious problems such as fouling, slagging and corrosion during thermal conversion processes of biomass. But amounts of leachates remain to be disposed. Investigating the organics release will be helpful to the leachate disposal. In this study, four types of biomass are water washed at different temperatures. The organic species and DBP (di-n-butyl phthalate) concentrations in leachates are determined by GC-MS. The results show that organics tend to release in the high-temperature region (60–90 °C). At 90 °C, 80% of organic matters in the wheat straw leachate are AR (aromatic hydrocarbons) and AL (alkanes, cycloalkanes and heterocyclic hydrocarbons). The organics distributions in the rice hull leachate are relatively uniform, compared with other leachates. The DBP concentrations in four leachates at 90 °C are lower than that at 30 °C because of its volatility. DBP concentrations in rice hull and corn stalk leachates show a trend of “reduction−increase”, with minimum values of 0.0001 and 0.001 mg L−1 at 60 °C, respectively. Whereas in the sorghum stalk leachate, a tendency of “increase−reduction” is observed. The corresponding content achieves the maximum value of 0.024 mg L−1.

Di-n-butyl phthalate-induced phytotoxicity in Hordeum vulgare seedlings and subsequent antioxidant defense response

Di-n-butyl phthalate (DBP) is one of the frequently detected phthalates in environmental samples. The effects of phthalates are extensively studied in the animals but the effects on plants are scarce. Therefore, the present study is aimed to envisage the effects of DBP on the antioxidative defense system in Hordeum vulgare L. seedlings grown under laboratory conditions for 7 d. The activities of different antioxidative enzymes were enhanced in the shoots. In the roots, the activity of guaiacol peroxidase increased and the catalase activity decreased initially but increased at higher DBP concentrations, whereas the activities of superoxide dismutase, ascorbate peroxidase, and glutathione reductase declined. Furthermore, the content of polyphenols elevated after exposure of seedlings to DBP. The possible reason for these responses of barley seedlings is the oxidative burst, i.e., enhanced production of reactive oxygen species, which were confirmed using confocal microscopy in terms of loss in plasma membrane integrity. DBP also disturbed the normal stomatal morphology of barley seedlings. The study may help to provide insights into the defense of crop plants against phthalate stress.

Di-n-butyl phthalate (DBP) reduces epithelial-mesenchymal transition via IP3R in hypospadias during maternal exposure.

This study focused on the oxidative stress effect of di-n-butyl phthalate (DBP) on development of the urinary system. We examined the mRNA expression of genital tubercle (GT) in control and DBP induced hypospadias group by Affymetrix Rat 230 2.0 Array. Real-time PCR and Western Blot were used to detect the protein and mRNA expression levels of inositol-1,4,5-triphate-receptor (IP3R) and epithelial-mesenchymal-transition (EMT)-related molecular markers, such as E-cadherin, β-Catenin, Snail, N-cadherin, in the GT of hypospadiac male rats and controls. The results of array were further confirmed in vitro. The changes of intracellular calcium concentration in urethral epithelial cells were detected by Fluo-3-AM before and after DBP treatment. The levels of reactive oxygen species (ROS) in urethral epithelial cells were measured by DCFH-DA with different concentrations of DBP (0, 1, 10, 100μmol/L) treatment. The mRNA expression profiles of GT in control and DBP induced hypospadias group showed high expression of IP3R and the abnormalities of EMT. Compared to the control group, the expression levels of IP3R, E-cadherin and β-Catenin increased at both the protein and mRNA levels. However the expression levels of Snail and N-cadherin decreased. The intracellular calcium concentration increased significantly after DBP treatment. The effect of DBP on urethral epithelial cells was linked to the generation of oxidative stress. DBP can influence the development of GT through its oxidative stress effect, which significantly increases the concentration of calcium and inhibits EMT in urethral epithelial cells, and block the fusion process of urethral groove, causing the occurrence of hypospadias. This study provides a new understanding of DBP's molecular mechanisms on hypospadias and may lead to new treatment strategies for the disease.

Uptake and accumulation of di-n-butyl phthalate in six leafy vegetables under hydroponic conditions

The uptake and accumulation of di-n-butyl phthalate (DBP) in six leafy vegetables was investigated under hydroponic conditions. The test vegetables were six varieties of Brassica campestris ssp., including Kangresijiqing (KRSJQ), Xiadiqing (XDQ), Ziyoucai (ZYC), Aijiaohuang (AJH), Shanghaiqing (SHQ) and Gaogengbai (GGB). The root concentration factor (RCF), translocation factor (TF) and transpiration stream concentration factor (TSCF) were calculated in order to compare the difference of uptake and accumulation behaviours of DBP in vegetable varieties. The results showed that DBP was easily concentrated in vegetable roots, but was poorly translocated from the roots to the shoots. Among the six vegetables, the ability of concentrating DBP from the solution to shoots was the highest in GGB, followed by ZYC, KRSJQ, AJH, SHQ and XDQ. High concentrations of DBP (5.0 mg/L) seem to inhibit normal physiological activity in the vegetables, which resulted in a higher RCF and a lower TF and TSCF than in low-concentration treatment. The results will help to evaluate the safety of agricultural products and to provide evidence for screening DBP pollution-safe vegetable cultivars.Graphical abstract

Effects of rice straw biochar on sorption and desorption of di-n-butyl phthalate in different soil particle-size fractions

Sorption of organic contaminants by biochar greatly affects their bioavailability and fate in soils. Nevertheless, very little information is available regarding the effects of biochar on sorption and desorption of organic contaminants in different soil particle-size fractions. In this study, di-n-butyl phthalate (DBP), a prevalent organic contaminant in agricultural soils, was taken as a model contaminant. The effects of biochar on DBP sorption and desorption in six particle-size fractions (i.e., coarse sand, fine sand, coarse silt, fine silt, clay, and humic acid fractions) of paddy soil were investigated using batch sorption-desorption experiments. A straw-derived biochar with high specific surface area (116 m2/g) and high content of organic matter (OM) rich in aromatic carbon (67%) was prepared. Addition of this biochar (1% and 5%) significantly promoted the sorption and retention of DBP in all the paddy soil particle-size fractions at environmentally relevant DBP concentrations (2–12 mg/L) with 1.2–132-fold increase of the Kd values. With increasing addition rates of biochar, DBP retention by the biochar enhanced. The biochar’s effectiveness was remarkably influenced by the physicochemical properties of the soil particle-size fractions, especially, the OM contents and pore size showed the most striking effects. A parameter (rkd) reflecting the biochar’s effectiveness showed negative and positive correlations with OM contents and pore size of the soil particle-size fractions, respectively. Accordingly, strong effect of the biochar was found in the soil fractions with low OM contents and high pore size. The findings of this study gave insight into the effects and influencing factors of biochar on sorption and desorption of organic contaminants in soils at scale of various particle-size factions.

Transformation of di-n-butyl phthalate in an anaerobic/anoxic/oxic leachate treatment process

Transformation of di-n-butyl phthalate (DBP) was investigated in anaerobic/anoxic/oxic (A/A/O) leachate treatment processes. Good removal was achieved under A/A/O conditions. Although the DBP removal was affected by the initial DBP concentration, the overall DBP removal efficiencies for this system were high (> 94%). Only traces of DBP remained in the effluent. The results of mass balance calculations indicated that approximately 33.7–50.7% of the DBP was degraded by the activated sludge, 48.9–64.9% accumulated in the system, and 0.4–1.4% was contained in the final effluent. This confirms that biodegradation and adsorption to activated sludge are both major mechanisms for DBP removal from leachate. The results of correlations between the DBP removal efficiencies and leachate contaminants indicated that the total nitrogen (TN) and total phosphorus (TP) may be key factors influencing the biodegradation of DBP. Half of the DBP in the system adsorbs on the activated sludge. This differs from previous studies in which DBP was mostly biodegraded. DBP is not completely removed when it adsorbs onto sludge. Therefore, methods for decreasing DBP adsorption and increasing the biodegradation efficiencies of the leachate treatment processes should be investigated in future.

Reservoir bottom sediments as heterogeneous catalysts for effective degradation of a selected endocrine-disrupting chemical via a Fenton-like process

The work detailed here investigated the efficiency of Fenton-like processes in degrading endocrine-disrupting chemicals, as exemplified by di-n-butyl phthalate (DBP). Specifically, a heterogeneous Fenton process was applied, as catalyzed by natural or modified bottom sediments collected from Rzeszów and Solina Reservoirs (Poland). A number of sediments with different physicochemical properties and different contents of Fe, Mn and Cu were in fact obtained and used, with “modification” entailing ion-exchange reaction and impregnation. It thus proved possible to demonstrate the possibility and legitimacy of Fenton's reagent being modified by natural bottom sediments that may therefore be regarded as heterogeneous catalysts, given a status as endogenous sources of iron, manganese and copper ions. While the effectiveness of DBP degradation was indeed influenced by sediment type and composition (and modification thereof), it was also affected by the factors of time, pH, DBP concentration, sediment dose and H2O2. The use of natural bottom sediments in the role of solid catalysts in heterogeneous Fenton processes represents a promising alternative to environmental remediation technology, given their abundance, low cost and environment-friendly nature.

PM2.5 bound phthalates in four metropolitan cities of China: Concentration, seasonal pattern and health risk via inhalation

Phthalates (PAEs) are in a group of artificial chemicals with potential adverse effects to human health and they can be frequently detected in environmental matrices due to its extensive usage. However, seasonal patterns of concentrations in atmosphere and risks posed by PAEs in airborne PM2.5 to Chinese population have not been well characterized. During the period of November 2015 to March 2017, samples of fine particulate matter (PM2.5) were collected in four cities of Guangzhou, Shanghai, Beijing and Harbin, which are major metropolitan areas of various latitudes of China. Concentrations of fourteen PAEs in airborne PM2.5 were quantified using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Estimated daily intakes (EDIs), hazard quotients (HQs) and hazard index (HI) were calculated. Lifetime average daily doses (LADD) and incremental lifetime cancer risks (ILCR) of di(2-ethylhexyl) phthalate (DEHP) for four age groups, which divide with infant, toddler, adolescent and adult, by inhalation route were evaluated. Dimethyl phthalate (DMP), Diethyl phthalate (DEP), Di-n-butyl phthalate (DBP), and DEHP were the four major PAEs contaminants in these PM2.5 samples. The sum concentrations of DMP, DEP, DBP and DEHP in Guangzhou, Shanghai, Beijing and Harbin ranged from 32.5–76.1, 10.1–101, 8.02–107 and 13.5–622 ng/m3, with mean concentrations of 59.1, 50.8, 43.8 and 136 ng/m3, respectively. The concentration of total PAEs in PM2.5 from higher latitudes city (Harbin) was higher than those from lower latitudes cities (Guangzhou and Shanghai). Total concentrations of PAEs were significantly higher during warmer seasons than those during colder seasons among the four cities. Although the EDIs, HQs, and HI for all age groups were less than the threshold set by the U.S. Environmental Protection Agency (US EPA) and European Food Safety Authority (EFSA), the highest values of 70-years ILCR from Shanghai and Harbin were 1.2 × 10−6 and 1.3 × 10−6, which were slightly beyond the acceptable level of 10−6. These findings reveal that the cancer risks of DEHP bound to PM2.5 in these two cites should be of particular concern.

The role of ANXA5 in DBP-induced oxidative stress through ERK/Nrf2 pathway

Di-N-butylphthalate (DBP) have given rise to more and more attention due to its unique endocrine toxicity to male reproductive system. Our previous studies have demonstrated antioxidative Nrf2 (nuclear factor erythroid related factor 2) pathway play a vital role in DBP induced oxidative stress injury. ANXA5 (annexin A5), which is highly expressed in testicular Leydig and Sertoli cells, was found upregulated after DBP stimulation. Mouse Leydig and Sertoli cells were exposed to different concentration of DBP for 24 h to examine the ROS (Reactive oxygen species), MDA (Malondialdehyde), SOD (superoxide dismutase) level and ANXA5, Nrf2, NQO1 (NAD(P)H-quinone oxidoreductase 1), HO-1 (heme oxygenase 1) and ERK/P-ERK protein expression by DHE (Dihydroethidium) staining, ELISA (enzyme-linked immunosorbent assay) and Western blot respectively. Firstly, the oxidative stress injury induced by DBP was re-validated. Then, we confirmed the change of Nrf2 pathway and ANXA5 level after DBP exposure to testicular cells. Additionally, overexpressed ANXA5 could activate Nrf2/HO-1/NQO1 antioxidant pathway and significantly attenuate DBP-induced oxidative stress. Ultimately, we demonstrated ANXA5 could increase ERK phosphorylated level and the activated role of ANXA5 on ERK/Nrf2 pathway could be reversed by ERK inhibitor. Overall, this study illuminated that ANXA5 could defend testicle Leydig and Sertoli cells against DBP-induced oxidative stress injury through ERK/Nrf2 pathway.

The use of alternative catalysts in processes of the chemical degradation of di-n-butyl phthalate in aqueous solutions

The work detailed here investigated the efficiency of oxidising technologies in clearing aqueous solutions of di-n-butyl phthalate (DBP), a known endocrine-disrupting compound (EDCs). Specifically, this paper addresses the use of the classic Fenton process, and the development of a modification of Fenton's reagent targeted at the degradation of di-n-butyl phthalate in aqueous solution. The modification in question entailed the use of alternative catalysts or a mixture thereof. Hence oxidation by hydrogen peroxide (at various different concentrations), the classic Fenton process, was tested for the removal of DBP, alongside versions modified in terms of the quantitative and qualitative composition of a mixture of catalysts, and the presence of metal ions, as well as the factors of time, pH and initial DBP concentration. Given that it did not exceed 31%, the degradation of DBP we achieved using H2O2 could not be regarded as satisfactory. In contrast, the addition of 2.5 mM L−1 of Fe2+ was found to mediate almost complete elimination of the phthalate from the model solution. Also confirmed by experimentation were the benefits of using homogeneous catalysts (compounds of copper(II) and manganese(II)) as alternatives to Fe2+ in the Fenton reagent. A key experimental achievement was to confirm the applicability of a catalyst formed from a mixture of 2 or 3 types of transition metal ion. A Fenton reaction extended to ions like Mn2+ and Cu2+ in particular is seen to eliminate factors/parameters discouraging practical industrial use of the classic Fenton process.

Di-n-butyl phthalate degrading endophytic bacterium Bacillus amyloliquefaciens subsp. strain JR20 isolated from garlic chive and its colonization in a leafy vegetable

Di-n-butyl phthalate (DBP) is one of the primary PAEs (phthalate acid esters) pollutants. DBP can be absorbed by plants and threaten human health via the food chain. Some DBP-degrading bacteria have been successfully isolated from the environment (water, soil, etc.). However, only a few DBP-degrading plant endophytes have been isolated. In this study, an endophytic bacterium, Bacillus amyloliquefaciens subsp. strain JR20, which was found capable of degrading DBP, was isolated from garlic chive. We found that strain JR20 metabolized 89.74% of DBP at a 5 mg/L concentration within 4 d in liquid mineral salts medium (MSM). The optimized conditions for maximum removal of DBP were as follows: DBP concentration, 5 mg/L; pH, 7–8; temperature, 30–40 °C. The colonization of strain JR20 significantly improved the degradation rate of DBP in the roots, stems and leaves of leafy vegetables.

Effects of di-n-butyl phthalate on photosynthetic performance and oxidative damage in different growth stages of wheat in cinnamon soils

Herein, we investigated the effects of di-n-butyl phthalate (DBP) on photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) content, oxidative damage, and biomass accumulation of different tissues in wheat (Triticum aestivum L) planted in cinnamon soils. The photosynthetic or fluorescence parameters (except for the intercellular carbon dioxide concentration), chlorophyll content, RuBisCO content, and biomass of roots, stems, and leaves decreased at the seedling, jointing, and booting stages under the stress of DBP. Compared with the control, the content of superoxide anions and hydrogen peroxide in the roots, stems, and leaves increased with increasing DBP concentrations at the seedling, jointing, and booting stages. The activities of superoxide dismutase (SOD) and catalase (CAT) in the roots, stems, and leaves increased under the 10 and 20 mg kg−1 DBP treatments; however, no significant changes were observed under the 40 mg kg−1 DBP treatment at the seedling stage (except for the SOD activity in roots). The increase in SOD and CAT activities in the roots, stems, and leaves with increasing DBP concentration at the jointing and booting stages suggested that an increase in the activities of these antioxidant enzymes may play an important role in defending against excess reactive oxygen species under DBP stress. The biomass of wheat roots, stems, and leaves decreased with an increase in DBP concentration, which was presumably caused by a decrease in photosynthesis and RuBisCO. The effect of DBP on wheat roots, stems, and leaves decreased with wheat growth.