Di-(2-ethylhexyl) Phthalate Concentrations Research Articles

Occurrence and distribution of microplastic particles and the concentration of Di 2-ethyl hexyl phthalate (DEHP) in microplastics and wastewater in the wastewater treatment plant

Wastewater treatment plant (WWTP) is one of the significant sources of Microplastics (MPs) release to the environment. Di 2-ethyl hexyl phthalate (DEHP) is used as an additive for more flexibility of plastics. In this study, we determined the number, size, shape, and color distribution of MPs as well as the concentration of DEHP in MPs and wastewater during the wastewater treatment process in WWTP. Samples were collected from 4 stations of different treatment stages of WWTP. The microplastic particles and the concentration of DEHP were detected via the fluorescence and polarized light microscopy and GC/MS instrument, respectively. The number of MPs decreased from 9.2 (station 1) to 0.84 MP/L (the final treated effluent) during the wastewater treatment process. Also, the size of MPs at the last station was smaller than the other stations. The mean concentrations of DEHP in MPs in stations 1, 2, 3 and 4 had the respective values of 83.3, 61.05, 30.62 and 17.49 μg/g, while the mean concentrations of DEHP in wastewater in stations 1, 2, 3 and 4 were 30.08, 25.07, 9.56, and 8.13 μg/L, respectively. This study shows that despite the removal of high amounts of MPs and DEHP in the final effluent of WWTP, due to the high volume of this effluent (2.828 × 108 L/d), significant amount of MPs (2.419 × 107 MP/day) and DEHP enter the aquatic environment daily, which may threaten the health of the fish and aquatic organisms and ultimately on the health of the local population.

Occurrence, migration and health risk of phthalates in tap water, barreled water and bottled water in Tianjin, China

This study was to investigate the occurrence, migration and health risk of phthalic acid esters (PAEs) in tap water, barreled water and bottled water in Tianjin, China. Six priority controlled PAEs were measured, among which the detection frequency of butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) was 100%, while the others were not detected. The concentration of DEHP was higher than BBP and DBP in all the samples. The initial ∑3PAEs concentrations in tap water, barreled water and bottled water were 2.409 ± 0.391 μg/L, 1.495 ± 0.213 μg/L and 1.963 ± 0.160 μg/L, respectively. Boiling tap water could reduce the PAEs content to an extent, but they increased significantly in hot tap water contacting with disposable plastic cups. The migration of PAEs in barreled water and bottled water were positively correlated with storage time and temperature, which could be described by exponential models. The hazard indexes of PAEs in different types of drinking water were very low. However, the human carcinogenic risks of DEHP will reach the maximum acceptable risk level of 10−6 when bottled water is stored for 8.8 days at 40 °C, 7.7 days at 50 °C, or 6.1 days at 60 °C.

Endocrine Disruptors and Polycystic Ovary Syndrome: Phthalates

Objective:We aimed to investigate a possible role of the endocrine disruptors phthalates, di-2-ethylhexyl phthalate (DEHP) and mono (2-ethylhexyl) phthalate (MEHP), in polycystic ovary syndrome (PCOS) aetiopathogenesis. We also wished to evaluate the relationship between phthalates and metabolic disturbances in adolescents with PCOS.Methods:A total of 124 adolescents were included. Serum MEHP and DEHP levels were determined by high-performance liquid chromatography. Insulin resistance was evaluated using homeostasis model assessment-insulin resistance, quantitative Insulin Sensitivity Check Index, fasting glucose/insulin ratio, Matsuda index, and total insulin levels during oral glucose tolerance test. Participants were further subdivided into lean and obese subgroups according to body mass index (BMI).Results:Sixty-three PCOS and 61 controls, (mean age 15.2±1.5; range: 13-19 years) were enrolled. Serum DEHP and MEHP concentrations were not significantly different between PCOS and control groups. The mean (95% confidence interval) values of DEHP and MEHP were 2.62 (2.50-2.75) μg/mL vs 2.71 (2.52-2.90) μg/mL and 0.23 (0.19-0.29) μg/mL vs 0.36 (0.18-0.54) μg/mL in PCOS and the control groups respectively, p>0.05. Correlation analysis, adjusted for BMI, showed that both phthalates significantly correlated with insulin resistance indices and serum triglycerides in adolescents with PCOS.Conclusion:Serum DEHP and MEHP concentrations were not different between adolescents with or without PCOS. However, these phthalates are associated with metabolic disturbances such as dyslipidemia and insulin resistance, independently of obesity, in girls with PCOS.

DEHP-elicited small extracellular vesicles miR-26a-5p promoted metastasis in nearby normal A549cells.

Small extracellular vesicles (sEV) are small lipid bilayer particles released by cells. sEV have been shown to play critical roles in intercellular communication. Di (2-ethylhexyl) phthalate (DEHP), widely used as plasticizers, has been detected in the environment and human beings. DEHP was found to exist in the air particles and showed pulmonary toxicity. However, there's little knowledge about the role of sEV in mediating the toxicity of DEHP-induced lung toxicity. We hypothesized that sEV mediated the toxicity of DEHP through their cargo. To validate this, lung epithelial cells (A549) were exposed to various concentrations (0, 0.2, 2 and 20μM) of DEHP for 48h. sEV extracted from DEHP-exposed A549cells were cultured with unexposed A549cells. Results showed that DEHP induced the epithelial-mesenchymal transition (EMT) and promoted the migration and invasion ability of A549cells. The number of released sEV significantly increased in the culture media in DEHP-exposed groups compared to unexposed groups. The sEV can enter the unexposed A549cells and enhance its EMT and the ability of migration and invasion. Treatment with GW4869 in DEHP-exposed A549cells almost blocked the effects of DEHP-elicited sEV in normal A549cells. Sequencing and functional analysis showed that the enrichment of significantly differentially expressed sEV miRNAs were related to tumor etiology. MiR-26a-5p was significantly enriched in DEHP-elicited sEV. Inhibition of miR-26a-5p in DEHP-exposed cells led to the downregulation of miR-26a-5p in sEV, and thus abolished the effects of DEHP-elicited sEV in normal A549cells, whereas overexpression of miR-26a-5p restored the effects. The transcription factors twist is one of the downstream targets in the effects of sEV-miR-26a-5p on EMT process. In all, our results showed that DEHP exposure promoted the secretion of miR-26a-5p in sEV, which subsequently enhanced the EMT, migration and invasion ability in neighboring normal cells via the twist.

Multiple transcriptomic profiling: p53 signaling pathway is involved in DEHP-induced prepubertal testicular injury via promoting cell apoptosis and inhibiting cell proliferation of Leydig cells

Di(2-ethylhexyl) phthalate (DEHP) is a widely-used plasticizer and has long been recognized as an endocrine-disrupting chemical with male reproductive toxicities. DEHP exposure at the prepubertal stage may lead to extensive testicular injury. However, the underlying mechanisms remain to be elucidated. In the present study, we gavaged male C57BL/6 mice with different concentrations of DEHP (0, 250, and 500 mg/kg-bw·d) from postnatal day 22–35, and exposed TM3 Leydig cells with 0, 100, 200, 300, and 400 μM of MEHP (bioactive metabolite of DEHP) for 12–48 h. RNA sequencing was performed both in testicular tissue and TM3 cells. The results showed that DEHP disrupts testicular development and reduces serum testosterone levels in male prepubertal mice. Bioinformatic analysis and experimental verification have revealed that DEHP/MEHP induces cell cycle arrest in TM3 cells and increases apoptosis both in vivo and in vitro. Furthermore, the p53 signaling pathway was found to be activated upon DEHP/MEHP treatment. The inhibition of p53 by pifithrin-α significantly reduced MEHP-induced injuries in TM3 cells. Cumulatively, these findings revealed the involvement of the p53 signaling pathway in DEHP-induced prepubertal testicular injury by promoting cell apoptosis and inhibiting cell proliferation of Leydig cells.

Synthesis and Evaluation of Molecularly Imprinted Polymers for the Determination of Di(2-ethylhexyl) Phthalate (DEHP) in Water Samples.

A molecularly imprinted polymer for the selective determination of Di(2-ethylhexyl) phthalate (DEHP) in water was synthesized and evaluated. This was accomplished by the use of sodium methacrylate as the monomer, toluene as a porogen, ethylene glycol dimethacrylate as a crosslinker, azobisisobutyronitrile as initiator and DEHP as a template molecule to generate the selectivity of the polymer for the compound, as well as synthesizing non-imprinted polymers. Three different polymerization approaches were used, emulsion, bulk and co-precipitation, the polymers obtained by emulsion presented a high retention rate reaching 99%. The method was able to pre-concentrate DEHP in water samples up to 250 times. To evaluate the applicability of the method, concentrations in fortified and bottled water were assessed using our polymer and determining DEHP concentrations by gas chromatography with mass spectrometry. Reported concentrations in bottled water were 12.1µg/L, well above reference values established by the U.S. Environmental Protection Agency.

Associations between prenatal phthalate exposure and sex-typed play behavior in preschool age boys and girls

Phthalates, a class of chemicals found widely in consumer products including plastic toys, food contaminants and food packaging, personal care products, cosmetics, air fresheners, and some medications, have been shown to be anti-androgenic in numerous laboratory and epidemiological studies. In a prior cohort enrolled in 2000–2002, we observed associations between prenatal urinary concentrations of di-ethyl hexyl phthalate (DEHP) and dibutyl phthalate (DBP) metabolites and less male-typed play behavior in preschool age boys. The aim of this study was to examine phthalate exposure in pregnancy in relation to play behavior at age 4 years in a larger cohort of pregnant women enrolled in The Infant Development and the Environment Study (TIDES) between 2010 and 2012 at four study sites (Minneapolis, MN; Rochester, NY; San Francisco, CA; Seattle, WA). Maternal urinary metabolites of DEHP, DiBP, DnBP, BBzP, and DEP were measured during the first (n=498) and third trimester (n=468) and mothers completed the Preschool Activities Inventory (PSAI), a validated maternal questionnaire designed to assess child toy preference and sex-typed play behavior when children were 4–5 years of age. After adjusting for child age, maternal education, race, urine dilution, parental attitudes about opposite sex-typed play behavior, and presence of a same sex older sibling, we observed associations between first trimester (mean 10.7±2.1 weeks gestation) (log10) SpG-adjusted MnBP, MiBP, and MBzP and lower masculine scores in boys (β-coefficient [95% confidence intervals]: MnBP −2.18, [-4.16, −0.20]), MiBP −2.1[-4.3,0.1], and MBzP -2.42 [-4.12, −0.71]). In girls, first trimester maternal urinary MBzP was associated with lower masculine scores (-2.12 [-3.98,-0.25]), while third trimester (mean 32.8±3.0 weeks gestation) maternal urinary MiBP was associated with higher masculine scores (2.69 [0.68,4.70]). Third trimester maternal urinary phthalate levels were not associated with play behavior in boys. These findings in boys are largely consistent with previous studies that report that prenatal phthalate exposure is associated with less masculine play behavior. No associations in girls have been previously reported.

Stabilization of Lipid Membranes through Partitioning of the Blood Bag Plasticizer Di-2-ethylhexyl phthalate (DEHP).

The safe storage of blood is of fundamental importance to health care systems all over the world. Currently, plastic bags are used for the collection and storage of donated blood and are typically made of poly(vinyl chloride) (PVC) plasticized with di-2-ethylhexyl phthalate (DEHP). DEHP is known to migrate into packed red blood cells (RBC) and has been found to extend their shelf life. It has been speculated that DEHP incorporates itself into the RBC membrane and alters membrane properties, thereby reducing susceptibility to hemolysis and morphological deterioration. Here, we used high-resolution X-ray diffraction and molecular dynamics (MD) simulations to study the interaction between DEHP and model POPC lipid membranes at high (9 mol %) and low (1 mol %) concentrations of DEHP. At both concentrations, DEHP was found to spontaneously partition into the bilayer. At high concentrations, DEHP molecules were found to aggregate in the aqueous phase before inserting as clusters into the membrane. The presence of DEHP in the bilayers resulted in subtle, yet statistically significant, alterations in several membrane properties in both the X-ray diffraction experiments and MD simulations. DEHP led to (1) an increase of membrane width and (2) an increase in the area per lipid. It was also found to (3) increase the deuterium order parameter, however, (4) decrease membrane orientation, indicating the formation of thicker, stiffer membranes with increased local curvature. The observed effects of DEHP on lipid bilayers may help to better understand its effect on RBC membranes in increasing the longevity of stored blood by improving membrane stability.

Development of circuit models for electrochemical impedance spectroscopy (EIS) responses of interdigitated MEMS biochemical sensors

Abstract Biochemical sensors using electrochemistry impedance spectroscopy often exploit electrical circuits to explain the electrochemical phenomena in the sensor-solution systems such as charge transport, double-layer effect and diffusion. Interdigitated sensors presented in the literature use a variety of circuits with different components and configurations to express the electrochemistry of the system. This work provides a comprehensive analysis of different electrical circuits used to interpret the system's behavior. A MEMS interdigitated sensor is used to obtain Nyquist plots of different concentrations of di-ethylhexyl phthalate (DEHP) in deionized water. The experimental data are used to examine equivalent electrical circuits with different levels of circuit complexity and for different frequency ranges. A curve fitting software is used to fit the circuit model to the tested data, and the results show equivalent circuits that include different electrical components and configurations can successfully predict the behavior of the system and explain electrochemical phenomena in the sensor-solution system. The circuit designs show that more complicated circuit models, using separate interfacial components for each electrode, may provide more accurate results, but they also may create complications in the curve-fitting optimization process. The circuit models and analysis presented here can be utilized for different biochemical sensing applications.

The role of STAT3/p53 and PI3K-Akt-mTOR signaling pathway on DEHP-induced reproductive toxicity in pubertal male rat

Di (2-ethylhexyl) phthalate (DEHP) is a known environmental endocrine disruptor that impairs development of testis and spermatogenesis. This study aims to explore the effects of STAT3/p53 and PI3K-Akt-mTOR signaling pathway on DEHP-induced reproductive toxicity in pubertal male rat. 24 6-week-old male Sprague-Dawley rats were randomly divided into 4 groups (Control, low-dose, middle-dose and high-dose group) and were treated with increasing concentration of DEHP (0, 250, 500, 1000 mg/kg/day) respectively for 28 consecutive days by intragastric administration. Our results showed that DEHP exposure induced obvious morphological changes of testis, decreased organ coefficient of testis and sperm count, and increased testicular cell apoptosis in the 500 and 1000 mg/kg/day DEHP groups (p < .05). The serum testosterone decreased in a dose-dependent manner after treatment with DEHP. Furthermore, the exposure of DEHP elevated the levels of oxidative stress accompanied by upregulated expression of p53 and reduced expression of STAT3. In addition, compared with the control group, the expression of PI3K, p-Akt and p-mTOR proteins significantly decreased, whereas the downstream autophagy-related proteins phosphorylated ULK1, Beclin-1, Atg7, LC3-II obviously increased in the 250 mg/kg/day DEHP group (p < .05). The expression of p62 was reduced in DEHP-treated groups. Our data indicated that autophagy could be activated to protect testes from DEHP-induced reproductive damage by inhibiting PI3K-Akt-mTOR signaling pathway in the 250 mg/kg/day DEHP group. STAT3/p53-mediated mitochondrial apoptosis pathway might play a major role to cause testis injury and reproductive dysfunction in the 500 and 1000 mg/kg/day DEHP groups.

Gestational and pubertal exposure to low dose of di-(2-ethylhexyl) phthalate impairs sperm quality in adult mice

Di-(2-ethylhexyl)-phthalate (DEHP) is a compound widely used as a plasticizer, which can leach from plastics into the environment and thus influence human health. The aim of this study was to analyze whether exposure to an environmentally relevant dose of DEHP during mice fetal development or puberty can cause long-lasting changes detectable month/s after the last exposure. We used a DEHP concentration relevant to a daily human intake of 2.4–3 μg/kg of body weight/day. CD1 outbred mice were treated either in utero or postnatally during puberty and analyzed in adulthood. Analyzing fertility parameters using morphometric, histologic, genomic and proteomic methods we showed that DEHP exposure leads to decreased sperm concentration and quality, in both experimental groups. Moreover, the changes in anogenital distance, seminal vesicle weight, and testicular gene expression suggest a disturbance of androgen signaling in exposed animals. In conclusion, we hereby present, that the prenatal and pubertal exposure to a low dose of DEHP negatively influenced reproductive endpoints in male mice, and some of the effects were persistent until adulthood.

Pollution characteristics, spatial variation, and potential risks of phthalate esters in the water–sediment system of the Yangtze River estuary and its adjacent East China Sea

Spatiotemporal variability in seawater, spatial variation in sediment, pollution characteristics, and risks related to 16 phthalate esters (PAEs) were investigated in the Yangtze River estuary and its adjacent East China Sea. The total concentrations of ΣPAEs in surface water were 0.588–17.7 μg L−1 in summer, 2.63–22.9 μg L−1 in winter, and 1.93–20.7 μg L−1 in spring, with average values of 2.05, 10.2, and 4.89 μg L−1, respectively. PAE concentrations exhibited notable seasonal variations with the highest value in winter and the lowest value in summer. The seasonal variation in PAE concentrations may be influenced by runoff and diluted water from the Yangtze River. The chemical composition of PAEs showed that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP) had significantly higher (p < 0.05) concentrations than the other congeners and were the most abundant PAE species in sediment and seawater in all three seasons. In addition, DnBP and DiBP were the two main congeners in seawater, and DEHP concentrations were higher in sediment than in seawater. DEHP had higher potential risks to sensitive organisms in water environment than DnBP and DiBP, and DiBP and DnBP which presented high levels of risk in sedimentary environment. DMP and DEP in watery and sedimentary environments and DEHP in sedimentary environment showed no or low risks to sensitive organisms.

Bioremediation of di-(2-ethylhexyl) phthalate contaminated red soil by Gordonia terrae RL-JC02: Characterization, metabolic pathway and kinetics

Di-(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer and a representative endocrine disrupting chemical. The toxicological effects of DEHP on environmental and human health have been widely investigated. In this study, the DEHP-degrading bacterial strain RL-JC02 was isolated from red soil with long-term usage of plastic mulch, and it was identified as Gordonia terrae by 16S rRNA gene analysis coupled with physiological and biochemical characterization. The biodegrading capacity of different phthalic acid esters and related intermediates was investigated as well as the performance of strain RL-JC02 under different environmental conditions, such as temperature, pH, salinity and DEHP concentration. Specifically, strain RL-JC02 showed good tolerance to low pH, with 86.6% of DEHP degraded under the initial pH of 5.0 within 72 h. The metabolic pathway of DEHP was examined by metabolic intermediate identification via a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis in which DEHP was hydrolyzed into phthalic acid (PA) and 2-ethylhexanol (2-EH) via mono (2-ethylhexyl) phthalate (MEHP). PA and 2-EH were further utilized through the protocatechuic acid metabolic pathway and β-oxidation via protocatechuic acid and 2-ethylhexanoic acid, respectively. The application potential of strain RL-JC02 was confirmed through the bioremediation of artificial DEHP-contaminated red soil showing 91.8% DEHP degradation by strain RL-JC02 within 30 d. The kinetics analysis of DEHP degradation by strain RL-JC02 in soil demonstrated that the process followed the modified Gompertz model. Meanwhile, the cell concentration monitoring of strain RL-JC02 in soil with absolute quantification polymerase chain reaction (qPCR) suggested that strain RL-JC02 survived well during bioremediation. This study provides sufficient evidence of a robust degrader for the bioremediation of PAE-contaminated red soil.

Phthalates and non-phthalate plasticizers in sediment from Korean coastal waters: Occurrence, spatial distribution, and ecological risks

Due to regulations on phthalates, non-phthalate plasticizers (NPPs) are now used as an alternative. Limited studies have been conducted on the occurrence and distribution of NPPs. In this study, sediment samples were collected from 50 locations along the Korean coast to assess the occurrence, distribution, sources, and ecological risks of phthalates and NPPs. Phthalates and NPPs were detected in all sediments, indicating ubiquitous contamination of the coastal environment. Di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)terephthalate (DEHT) were dominant, suggesting that DEHT could be an emerging contaminant of concern. The highest concentrations of phthalates and NPPs were found in sediment samples from harbors, implying they are contaminated hotspots. Sedimentary organic carbon was a major factor governing the distribution of phthalates and NPPs. Significant correlations were observed among phthalates and NPPs, suggesting similar sources and geochemical behavior. DEHP concentration exceeded threshold values, indicating potential health risks to benthic organisms in sediments.

Uptake and toxicity of di-(2-ethylhexyl) phthalate in Brassica chinensis L

This work focuses on the bioaccumulation and toxic effects of di-(2-ethylhexyl) phthalate (DEHP) in the leafy vegetable Shanghaiqing (SHQ) (Brassica chinensis L.). The accumulated DEHP amount in the edible part and roots of SHQ increased as the DEHP concentration in the soil increased. DEHP accumulation was higher in the roots than in the edible part of the plant. The root concentration factors and bioaccumulation factors for DEHP in SHQ were 0.13–2.49 and 0.03–2.00, respectively. The DEHP translocation factors were below 1.0, indicating that DEHP preferentially accumulated in plant roots. The DEHP risk index in the edible part of SHQ in relation to the human body and in terms of dietary exposure risk assessment was also below 1.0, indicating a low health risk. High DEHP concentrations caused 1) inhibition of SHQ growth, 2) an increase in SHQ chlorophyll and malondialdehyde contents and 3) a decrease in soluble sugar and vitamin contents. Low DEHP concentrations stimulated total superoxide dismutase, peroxidase and catalase activities, while high DEHP levels showed an inhibitory effect. DEHP presence in soil affected not only SHQ growth but also quality. Our results provide the data needed for the proper assessment of food safety and the ecological impact of DEHP contamination in agricultural soils.

Correlation between urinary phthalate concentration and semen quality parameters

Objective To explore the correlation between urinary phthalate concentration and semen quality parameters. Methods A total of 112 males with infertility in our hospital were set as infertility group. Another 65 healthy males who had given birth during the same period in our hospital were selected as control group. The semen samples obtained by urine and masturbation were collected in all the subjects. The semen quality parameters were detected by automatic color sperm quality detection system, and the concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and Di 2-Ethyl Hexyl Phthalate (DEHP) in urine were measured by high performance liquid chromatography, and the correlation between concentrations of four phthalates and semen quality parameters was analyzed by spearman correlation coefficient. Results The concentrations of DMP, DEP, DBP, DEHP and total phthalate in infertility group were significantly higher than those in control group (P<0.05). The sperm density, sperm survival rate and ratios of a+ b level sperm and forward movement in infertility group were significantly lower than those in control group (P<0.05), and the ratio of abnormal sperm was significantly higher than that in control group (P<0.05). The concentrations of DMP, DEP, DBP and DEHP in urine were negatively correlated with sperm density, sperm survival rate and ratios of a+ b level sperm and forward movement (P<0.05), and were positively correlated with abnormal sperm ratio (P<0.05). Conclusions The concentration of phthalate is high in urine of infertile males, and its concentration is negatively correlated with semen quality. Phthalate accumulation may be one of the important reasons for male infertility. Key words: Urinalysis; Phthalate; Semen analysis; Infertility, male

Effects of bisphenol A, diethylhexyl phthalate and pentabrominated diphenyl ether 99 on steroid synthesis in cultured bovine luteal cells.

Bisphenol A (BPA), diethylhexyl phthalate (DEHP) and pentabrominated diphenyl ether 99 (PBDE 99) are environmental toxicants belonging to the endocrine disrupting compounds (EDCs). They exert adverse effects on the various physiological systems, especially the reproductive system of humans and animals. The aim of this study was to investigate the effects of BPA, DEHP and PBDE 99 on progesterone (P4) synthesis in cultured bovine luteal cells. The bovine luteal cells isolated from the mid-luteal corpora lutea were exposed to different concentrations of BPA (1, 3, 10 and 30µM), DEHP (1, 3, 10 and 30µM) and PBDE 99 (0.1, 0.3, 1 and 3µM) in a serum-free culture media for 48 and 96hr. At 48hr, the P4 level in the luteal cells decreased after treatment with all concentrations of BPA; 3, 10 and 30µM of DEHP; and 3µM of PBDE 99 compared to the control (p<.05). Treatment of cells with 3-30µM of BPA, 1-30µM of DEHP and 1-3µM of PBDE 99 for 96hr resulted in reduction in P4 synthesis (p<.05). However, lower concentrations of PBDE 99 (0.1 and 0.3µM) increased P4 levels at 48 and 96hr. Synthesis of P4 was lower at 96hr compared to the 48hr in the groups treated with BPA (30µM), DEHP (1-30µM), PBDE 99 (0.3-3µM) and control group. Our results showed that BPA, DEHP and PBDE 99 are able to alter luteal steroidogenesis in bovine cells and can disrupt hormonal balance in the ovary. However, it is necessary to evaluate the exact mechanism underlying these effects in future studies.

Spatial distribution of phthalate acid esters in sediments of the Laizhou Bay and its relationship with anthropogenic activities and geochemical variables

Spatial distribution and ecological risks of phthalate acid esters (PAEs) in sediments of the Laizhou Bay were investigated, and the relationships of PAEs with human activities and geochemical variables were studied in this work. Thirteen detectable PAEs were widespread occurrence, and the total PAE concentrations ranged from 813.1 to 11,975.6 μg/kg dry weight in sediments of the Laizhou Bay. Di-(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) were predominant and accounted for 51.9% of ΣPAEs. The major sources of PAEs with their characteristic PAE congeners or composition could be classified as riverine runoff from catchments of the Yellow River and the rivers Xiaoqing & Zhimai, and direct discharge from the west coast and Binhai Zone, according to continuous PAE spatial distribution patterns generated by GIS techniques. The concentrations of most PAEs gradually decreased from west inshore to east offshore in inverted S shapes, which was consistent with the tide field of the Laizhou Bay. There are negative correlations between sediment depth and all PAEs, and nine PAEs exhibited negative correlations with salinity using Pearson correlation analysis. Depth and salinity exerted negative influence on PAEs (contributions of 55.8% and 32.0%, respectively) according to redundancy analysis. The DBP concentrations of 15.1% sites exceeded the ERLs and only one site had the DEHP concentration exceeded environmental risk limits. The DBP risk quotient values of 11.3% (for algae), 3.8% (for crustaceans) and 43.4% (for fish) sites exceeded 1, and most of these sites are near to four major sources. These results might benefit the implementation of effective environmental management and remediation practices.

Trends for plasticizers in German freshwater environments – Evidence for the substitution of DEHP with emerging phthalate and non-phthalate alternatives

Plasticizers are marketed in high volumes and Di(2-ethylhexyl) phthalate (DEHP) is frequently detected in the environment and human populations. Industry had largely relied on DEHP until regulation started to restrict its marketing in 1999 due to environmental and human health concerns. The aim of this study was to obtain spatial-temporal trends for DEHP and its substitutes in German rivers. We have investigated suspended particulate matter (SPM) samples from the German Environmental Specimen Bank (ESB) for the presence of 23 plasticizers, i.e. 17 phthalates and 6 non-phthalates. The samples were collected in the last 10 years at 13 sites in large river basins in Germany such as the Rhine, Elbe and Danube. A decrease in DEHP concentrations was observed at all sampling sites between the mid-2000s and 2017. The maximum concentration for DEHP was determined in 2006 in samples from Rehlingen/Saar (6720 ng/g dry weight (dw)). By 2017, the DEHP concentration in Rehlingen had dropped to 2080 ng/g dw. Currently, Diisononyl phthalate (DINP) is the plasticizer with the highest levels in the SPM samples (maximum value 4150 ng/g dw in Rehlingen/Saar). Our results show that novel plasticizers such as Diisononylcyclohexane-1,2-dicarboxylate (DINCH) spread rapidly in surface waters after their market introduction. We have found several plasticizers of emerging concern in the environmental samples, the further use of which is currently under review under the EU chemicals regulation (REACH, registration, evaluation, authorisation and restriction of chemicals). In particular for Di(2-propylheptyl) phthalate (DPHP) a significant increase in concentration was observed at almost all sites between the mid-2000s and 2017, for example in Prossen/Elbe from 24 ng/g dw (2005) to 1380 ng/g dw (2017).

Enhanced biodegradation of an endocrine disrupting micro-pollutant: Di (2-ethylhexyl) phthalate using biogenic self-assembled monolayer of silver nanoparticles

Di (2-ethylhexyl) phthalate (DEHP) is one of the predominant plasticizer and an endocrine disrupting chemical occurring almost in all partitions of the environment. Though DEHP occur at lower concentration, reluctance arises due to their ability to disrupt endocrine system even lower concentration. In the present study, DEHP was assessed for degradation at minimal level (1–100 μg L−1) by a novel bacterial strain, Rhodococcus jostii PEVJ9. In the experimental design, significant variables were concentration of silver nitrate and DEHP, pH, temperature, time and agitation. Degradation without SAM-silver nanoparticles was 30–66% (predicted value = 30.8–66.8%, R2 = 99.7%) while, degradation in the presence of SAM-silver nanoparticles onto bacterial cells was 100% (predicted value = 98.4–102.1%, R2 = 99.6%) within 72 h. In short, this is the first report illustrating the experimental designs in biogenic synthesis of SAM-silver nanoparticles and enhanced degradation of DEHP at minimal level. The study overcomes poor bioavailability and assimilation of DEHP at lower concentration by the microbial population present in the environment. Thus, an efficient clean-up would prevent or minimize DEHP exposure at all trophic levels ranging from feminization of fishes to reproductive disorders in humans.