The potential health effects of phthalate esters in children's toys: a review and risk assessment

Two-Year Carcinogenicity Study of a Novel Plasticizer, bis(2-Ethylhexyl) Cyclohexane-1,4-Dicarboxylate (Eco-DEHCH), by Oral Diet in Han Wistar Rats

Plasticizers are necessary for the usability of various products, including food contact materials. Exposure to plasticizers is most commonly made through the oral route. Several plasticizers have been reported to have adverse effects on humans and the environment. Thus, the present study aimed to determine the long-term toxicity and carcinogenicity of a novel plasticizer called bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate (Eco-DEHCH), which is an ecofriendly and biologically less harmful replacer. Groups of 50 male and 50 female Han Wistar rats were fed Eco-DEHCH at daily doses of 1,600, 5,000, or 16,000 ppm in their diet for at least 104 weeks. The rats were regularly monitored for mortality, clinical signs, body weight, food consumption, food efficiency, and perceivable mass. All animals were subjected to complete necropsy and histopathological examination. The results indicate that the rats well tolerated chronic exposure to Eco-DEHCH at highest daily doses of 16,000 ppm, with was equivalent to 805.1 mg/kg/day in males and 1,060.6 mg/kg/day in females and did not show signs of toxicity or carcinogenicity. In conclusion, Eco-DEHCH could be a safe and promising alternative plasticizer.

Characteristics and health risks of population exposure to phthalates via the use of face towels

The production of face towels is growing at an annual rate of about 4% in China, reaching 1.13 million tons by 2021. Phthalates (PAEs) are widely used in textiles, and face towels, as an important household textile, may expose people to PAEs via the skin, further leading to health risks. We collected new face towels and analyzed the distribution characterization of PAEs in them. The changes of PAEs were explored in a face towel use experiment and a simulated laundry experiment. Based on the use of face towels by 24 volunteers, we calculated the estimated daily intake (EDI) and comprehensively assessed the hazard quotient (HQ), hazard index (HI), and dermal cancer risk (DCR) of PAEs exposure in the population. PAEs were present in new face towels at total concentrations of <MDL-2388 ng/g, with a median of 173.2 ng/g, which was a lower contamination level compared with other textiles. PAE contents in used face towels were significantly higher than in new face towels. The concentrations of PAEs in coral velvet were significantly higher than those in cotton. Water washing removed some PAEs, while detergent washing increased the PAE content on face towels. Gender, weight, use time, and material were the main factors affecting EDI. The HQ and HI were less than 1, which proved PAEs had no significant non-carcinogenic health risks. Among the five target PAEs studied, DEHP was the only carcinogenic PAE and may cause potential health risks after long-term exposure. Therefore, we should pay more attention to DEHP.

Evaluation of the 52-week chronic toxicity of a novel phthalate-free plasticizer, Eco-DEHCH (bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate), in Han Wistar rats

Phthalate esters (PEs) are the most widely used class of plasticizers. Several PEs, however, were found to have adverse effects on the health of animals. A new phthalate-free plasticizer, Eco-DEHCH (bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate), was recently developed as an ecofriendly replacement for phthalate plasticizers and to be less harmful to organisms. The present study evaluated the long-term toxicity of Eco-DEHCH in Wistar Han rats to explore adverse effects and predict hazardous potential to humans. Forty male and forty female Wistar Han rats were exposed to Eco-DEHCH in dietary feed for 52 weeks, and their hematologic, coagulation, and serum biochemical parameters were monitored. The rats were subjected to close clinical, ophthalmic, and histopathologic examinations and urinalysis throughout the consumption of Eco-DEHCH. The effects of this plasticizer on food consumption and organ weight were also determined. Chronic exposure to Eco-DEHCH was generally safe, although it also resulted in α_2u-globulin accumulation, a parameter with no human relevance. In conclusion, Eco-DEHCH can serve as a safe and promising alternative plasticizer.

An overview of organic contaminants in indoor dust, their health impact, geographical distribution and recent extraction/analysis methods

People spend a substantial proportion of their time indoors; therefore, exposure to contaminants in indoor dust is persistent and profuse. According to the findings of recent studies, contaminants such as flame retardants (FRs), organochlorines (OCs), and phthalate esters (PAEs) are more prevalent in indoor dust. The discrepancy in the geographical distribution of these chemicals indicates country-specific applications. However, many studies have revealed that chlorophosphates, polychlorinated biphenyls (PCBs) and di-2-ethylhexyl phthalate are frequently detected in indoor dust throughout the world. Although some chemicals (e.g., OCs) were banned/severely restricted decades ago, they have still been detected in indoor dust. These organic contaminants have shown clear evidence of carcinogenic, neurotoxic, immunogenic, and estrogenic activities. Recent extraction methods have shown their advantages, such as high recoveries, less solvent consumption, less extraction time and simplicity of use. The latest separation techniques such as two-dimensional gas/liquid chromatography, latest ionization techniques (e.g., matrix-assisted laser desorption/ionization (MALDI)), and modern techniques of mass spectrometry (e.g., tandem mass spectrometry (MS/MS), time-of-flight (TOF) and high-resolution mass spectrometry (HRMS)) improve the detection limits, accuracy, reproducibility and simultaneous detection of organic contaminants. For future perspectives, it is suggested that the importance of the study of dust morphology for comprehensive risk analysis, introducing standard reference materials to strengthen the analytical methods, adopt common guidelines for comparison of research findings and the importance of dust analysis in the developing world since lack of records on the production and usage of hazardous substances. Such measures will help to evaluate the effectiveness of prevailing legislations and to set up new regulations.

Mechanisms of MEHP Inhibitory Action and Analysis of Potential Replacement Plasticizers on Leydig Cell Steroidogenesis

Steroid production in Leydig cells is stimulated mainly by the pituitary luteinizing hormone, which leads to increased expression of genes involved in steroidogenesis, including the gene encoding the steroidogenic acute regulatory (STAR) protein. Mono(2-ethylhexyl)phthalate (MEHP), the active metabolite of the widely used plasticizer DEHP, is known to disrupt Leydig steroidogenesis but its mechanisms of action remain poorly understood. We found that MEHP caused a significant reduction in hormone-induced steroid hormone production in two Leydig cell lines, MA-10 and MLTC-1. Consistent with disrupted cholesterol transport, we found that MEHP represses cAMP-induced Star promoter activity. MEHP responsiveness was mapped to the proximal Star promoter, which contains multiple binding sites for several transcription factors. In addition to STAR, we found that MEHP also reduced the levels of ferredoxin reductase, a protein essential for electron transport during steroidogenesis. Finally, we tested new plasticizers as alternatives to phthalates. Two plasticizers, dioctyl succinate and 1,6-hexanediol dibenzoate, had no significant effect on hormone-induced steroidogenesis. Our current findings reveal that MEHP represses steroidogenesis by affecting cholesterol transport and its conversion into pregnenolone. We also found that two novel molecules with desirable plasticizer properties have no impact on Leydig cell steroidogenesis and could be suitable phthalate replacements.

Oxidative Stress and Cognitive Alterations Induced by Cancer Chemotherapy Drugs: A Scoping Review

Cognitive impairment is one of the most deleterious effects of chemotherapy treatment in cancer patients, and this problem sometimes remains even after chemotherapy ends. Common classes of chemotherapy-based regimens such as anthracyclines, taxanes, and platinum derivatives can induce both oxidative stress in the blood and in the brain, and these effects can be reproduced in neuronal and glia cell cultures. In rodent models, both the acute and repeated administration of doxorubicin or adriamycin (anthracyclines) or cisplatin impairs cognitive functions, as shown by their diminished performance in different learning and memory behavioural tasks. Administration of compounds with strong antioxidant effects such as N-acetylcysteine, gamma-glutamyl cysteine ethyl ester, polydatin, caffeic acid phenethyl ester, and 2-mercaptoethane sulfonate sodium (MESNA) counteract both oxidative stress and cognitive alterations induced by chemotherapeutic drugs. These antioxidant molecules provide the scientific basis to design clinical trials in patients with the aim of reducing the oxidative stress and cognitive alterations, among other probable central nervous system changes, elicited by chemotherapy in cancer patients. In particular, N-acetylcysteine and MESNA are currently used in clinical settings and are therefore attracting scientific attention.

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.

Sustainability Assessment with Integrated Circular Economy Principles: A Toy Case Study

When considering the sustainability of production processes, research studies usually emphasise environmental impacts and do not adequately address economic and social impacts. Toy production is no exception when it comes to assessing sustainability. Previous research on toys has focused solely on assessing environmental aspects and neglected social and economic aspects. This paper presents a sustainability assessment of a toy using environmental life cycle assessment, life cycle costing, and social life cycle assessment. We conducted an inventory analysis and sustainability impact assessment of the toy to identify the hotspots of the system. The main environmental impacts are eutrophication, followed by terrestrial eco-toxicity, acidification, and global warming. The life cycle costing approach examined the economic aspect of the proposed design options for toys, while the social assessment of the alternative designs revealed social impacts along the product life cycle. In addition, different options based on the principles of the circular economy were analysed and proposed in terms of substitution of materials and shortening of transport distances for the toy studied.

Detecting phthalate esters in sludge particulates from wastewater treatment plants

This study proposed a method for analysis of 10 phthalate esters compounds from wastewater treatment plant sludges. The analytical efficiency of GC-MS for of target compounds was verified by a standard mixture of phthalate esters. The response factors related to the respective internal standards from a five-point calibration curve quantified the phthalate esters in individual compounds. Based on the literature compiled by environmental agencies, new generation phthalate compounds have been developed, such as di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP), as alternative to conventional phthalates. The analytical results showed that the total PAEs concentration was in the range from 7.4 to 138.6 mg kg^-1 dw in these seven analyzed sludge samples. More, di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP) and bis(2-ethylhexyl) phthalate (DEHP) contributed to over 99% of PAEs in the sludge. The correlation between total PAEs concentration in household and sewage flow treated at seven WWTPs and concentrations of DEHP, DiNP and DiDP was significant.

Identification of plastic toys contaminated with volatile organic compounds using QCM gas sensor array

In this paper, we propose a fast and easy-to-use analytical method to identify the children toys contaminated with potentially dangerous substances from the class of volatile organic compounds (VOCs). It is shown that the use of cross-sensitive gas sensor array based on piezoelectric sensors, modified with different sorbents, allows reliable recognition of items with the elevated levels of VOCs. Applying chemometric methods for processing of the sensor array data, it is possible to classify the toys into clean and hazardous ones with sensitivity and accuracy around 96%. Taking into account the simplicity of the suggested procedure, it appears to be an attractive option for cost-effective pre-screening of potentially dangerous plastic toys in comparison with the expensive and time-consuming chromatographic methods.

Occurrence of phthalate esters in the eastern coast of Thailand

In this work, we investigated possible contamination of phthalates in seawater and sediment around the eastern coast of Thailand in the area of Chonburi, Rayong, and Chanthaburi. The main focus was on Pradu Bay east of Map Ta Phut, a well-known industrial and economic hub in Thailand. Among six selected phthalates of interest, diethyl phthalate (DEP), and benzyl butyl phthalate (BBP) were not found in any sample, while the concentrations of dimethyl phthalate (DMP) and dioctyl phthalate (DnOP) were very low or undetectable in most samples. In December 2014, the concentration of dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP) in Pradu Bay were 0.23-0.77 and 0.31-0.91 μg L^-1 in seawater, respectively and non-detected (ND)-0.80 and ND-1.65 μg g^-1 for 11 out of 20 sediment samples. DBP and DEHP were considered as the predominant congeners. A surface mapping system provided us an overview concentration distribution of DBP and DEHP congeners in seawater and sediment in Pradu Bay, showing a correlation between water and sediment and allowing a prediction of a possible point source. A comparison with the EU standard concentration limit in surface water confirmed that the phthalate concentration in this area was acceptable. However, continuous monitoring of phthalate congeners in the matrices should be done to detect a possible increase in their concentrations. To the best of our knowledge, this is the first study to determine concentrations of phthalates in seawater and sediment along the east coast of Thailand.

Migration and potential risk of trace phthalates in bottled water: A global situation

Increasing attention has been dedicated to trace phthalates in bottled water due to the serious concerns on public health, while there is still a lack of systematic analysis and assessment of current global situation. Through analyzing five representative phthalates in bottled water over 20 countries, this work clearly revealed the phthalates-associated potential risks in both human daily intake and estrogenic effect. In the risk assessment, the kinetic models were also developed to describe and predict phthalates migration. In more than three hundred brands of bottled waters from twenty one countries, the detection frequency of the five targeted phthalates was found to be in the order of dibutyl phthalate (DBP, 67.6%), di-2-(ethyl hexyl) phthalate (DEHP, 61.7%), diethyl phthalate (DEP, 47.1%), benzyl butyl phthalate (BBP, 36.9%), and dimethyl phthalate (DMP, 30.1%). Among the countries studied relating concentrations of DEHP in bottled waters, the top five countries ranked in the order of high to low were Thailand, Croatia, Czech Republic, Saudi Arabia and China with an average level of 61.1, 8.8, 6.3, 6.2 and 6.1 μg/L, respectively. The average levels of BBP, DBP, DMP and DEP in bottled water from Pakistan were high, in which DEP and DMP were ranked 1st among all countries with the average levels of 22.4 and 50.2 μg/L, while BBP and DBP were ranked 2nd and 3rd with the average levels of 7.5 and 17.8 μg/L, respectively. The human daily intake-based risk assessment revealed that phthalates in bottled waters studied would not pose a serious concern on public health. However, the adverse estrogenic effects of phthalates in bottled water from some countries appeared to be significant. This study just shed light on global situation of phthalates in bottled water, and more efforts should be needed to systematically examine the phthalates-related safety of bottled water.

Short-term toxicity of dibutyl phthalate to mice intestinal tissue

The objective of this study was to investigate changes in intestinal histopathology and expression of heat-shock proteins (HSPs) in the small intestinal tissue of mouse after acute exposure to dibutyl phthalate (DBP). Forty-eight 60-day-old Institute of Cancer Research (ICR) mice were administered DBP by gavage once a day for 10 days. The mice were divided into three groups of 16 mice each: the high-dose group was administered 500 mg/kg body weight (BW) DBP; the low-dose group was administered 50 mg/kg BW; and the control group was not administered DBP. Significant increases in the uterine index, ovary index, and testicular index were observed in the DBP-exposed groups compared to those in the control group. Villus height and V/ C ratio significantly increased ( p < 0.05) in the duodenum and decreased ( p < 0.05) in the jejunum after the administration of DBP. The goblet cell number decreased in both the duodenum and the jejunum of mice exposed to DBP ( p < 0.05) compared to the number in the control group mice. Damage to the structure of the small intestine was accompanied by a marked increase in HSP27 expression and a decrease in the expression of HSP70 and HSP90 in both high-dose and low-dose groups. These results indicate that elevated HSP27 levels in the duodenum and jejunum may be important markers for acute DBP exposure and that HSP27 may act as a protective protein involved in intestinal mucosa repair.

Lifetime cancer risk assessment for inhalation exposure to di(2-ethylhexyl) phthalate (DEHP)

The plasticizer di(2-ethylhexyl) phthalate (DEHP) is ubiquitous in the environment and considered as carcinogen; however, the carcinogenic risk of human exposure to DEHP in the air via inhalation is lacking. A probabilistic incremental lifetime cancer risk (ILCR) model was implemented to quantitatively estimate the potential cancer risk of DEHP via human inhalation by using Monte Carlo simulation. We assessed the cancer risk in different age groups (children, adolescents, and adults) exposed to different DEHP concentrations (background low, indoor moderate, and occupational high) for different durations (2, 8, and 20 years). Results showed that the cancer risk of exposure to DEHP was below the acceptable limit (10^-6) in the ambient air but was serious in indoor and occupational environments even at short exposure duration (2 years). The cancer risk of DEHP via inhalation in children was lower than that in adolescents and adults, but the risk in children via dermal and oral exposure to indoor dust and soft PVC toys should be considered. Sensitivity analysis indicated that the exposure concentration of DEHP was the strongest factor that influenced ILCR. Our work provides the evidence of cancer risk of DEHP via inhalation and highlights the risk in indoor and occupational environments.

Synthesis of phthalate-free plasticizers by hydrogenation in water using RhNi bimetallic catalyst on aluminated SBA-15

Phthalate was hydrogenated to phthalate-free product by RhNi nanoparticles on Al-SBA-15.

Solubility and Durability of Cardanol Derived Plasticizers for Soft PVC

The aim of this work is the analysis of the suitability of cardanol derivatives as primary plasticizer for polyvinyl chloride (PVC). Cardanol derived plasticizers (CDP) were obtained by acetylation of cardanol, followed by epoxidation of the side chain double bonds. The developed procedures allowed to achieve high yields of acetylated cardanol, whereas plasticizers characterized by different yields of epoxidation were obtained, according to the used synthesis procedure. Rheological analysis was used in order to study the gelation process of PVC plastisols with CDP. A comparison of commercial phthalate and natural derived plasticizers showed that the CDP are characterized by adequate gelation properties, involving a complete absorption of the plasticizers at relatively low temperatures. The gelation properties showed a strong dependence on the yield of the epoxidation. In particular, lower gelation temperatures, higher plasticizer absorption and faster gelation were observed for higher epoxy content in the plasticizer. Finally, ageing tests were performed on soft PVC produced by the CDP. The weight loss of soft PVC with CDP is comparable to that of commercial plasticizers, particularly at high yields of epoxidation.

Biodegradation of endocrine disruptor dibutyl phthalate (DBP) by a newly isolated Methylobacillus sp. V29b and the DBP degradation pathway

Bacteria of the genus Methylobacillus are methanotrophs, a metabolic feature that is widespread in the phylum Proteobacteria. The study demonstrates the isolation and characterization of a newly isolated Methylobacillus sp. V29b. which grows on methanol, protocatechuate, monobutyl phthalate, dibutyl phthalate, diethyl phthalate, benzyl butyl phthalate, dioctyl phthalate and diisodecyl phthalate. Methylobacillus sp. V29b was characterized with scanning electron microscopy, transmission electron microscopy, Gram staining, antibiotics sensitivity tests and biochemical characterization. It degrades 70 % of the initial DBP in minimal salt medium and 65 % of the initial DBP in samples contaminated with DBP. DBP biodegradation kinetics was explained by the Monod growth inhibition model. Values for maximum specific growth rate (µ_max) and half-velocity constant (K_s) are 0.07 h⁻¹ and 998.2 mg/l, respectively. Stoichiometry for DBP degradation was calculated for Methylobacillus sp. V29b. Four metabolic intermediates, dibutyl phthalate (DBP), monobutyl phthalate, phthalic acid and pyrocatechol, were identified. Based on the metabolic intermediates identified, a chemical pathway for DBP degradation was proposed. Six genes for phthalic acid degradation were identified from the genome of Methylobacillus sp. V29b.

Methods for the Determination of Endocrine-Disrupting Phthalate Esters

Phthalates are endocrine disruptors frequently occurring in the general and industrial environment and in many industrial products. Moreover, they are also suspected of being carcinogenic, teratogenic, and mutagenic, and they show diverse toxicity profiles depending on their structures. The European Union and the United States Environmental Protection Agency (US EPA) have included many phthalates in the list of priority substances with potential endocrine-disrupting action. They are: dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), diethylhexyl phthalate (DEHP), di-iso-nonyl phthalate (DINP), di-iso-decyl phthalate (DIDP), di-n-decyl phthalate (DnDP), and dioctyl phthalate (DOP). There is an ever-increasing demand for new analytical methods suitable for monitoring different phthalates in various environmental, biological, and other matrices. Separation and spectrometric methods are most frequently used. However, modern electroanalytical methods can also play a useful role in this field because of their high sensitivity, reasonable selectivity, easy automation, and miniaturization, and especially low investment and running costs, which makes them suitable for large-scale monitoring. Therefore, this review outlines possibilities and limitations of various analytical methods for determination of endocrine-disruptor phthalate esters in various matrices, including somewhat neglected electroanalytical methods.

The presence of macrophages and inflammatory responses in an in vitro testicular co-culture model of male reproductive development enhance relevance to in vivo conditions

Our 3-dimensional testis co-culture system (3D-TCS) represents a promising model of male reproductive toxicity which captures sensitive processes of male reproductive development and contains the main testes cell types (germ, Leydig and Sertoli cells). Macrophages are another cell type important for testicular function and help to modulate immuno-endocrine processes during testes development. Chemicals such as phthalate esters (PE's) affect macrophage function and testosterone production in the testes in vivo. The aim of this study was to determine whether macrophages were present in the 3D-TCS and investigate responses in our model that may be related to immuno-endocrine functions. We observed consistent expression of the resident macrophage marker ED2 as well as increases in inflammatory cytokines produced by macrophages and testes cells (IL-6, TNF-α and KC/GRO) after exposure to toxic PE's. Pathway analysis of gene expression changes after exposure to PE's showed that IL-6 and TNF-α signaling pathways were enriched after treatment with reproductively toxic, but not non-reproductively toxic phthalates. These results indicate that macrophages and inflammatory processes are captured in the 3D-TCS and that these processes are impacted by exposure to reproductive toxicants. These processes represent a major mode of action for in vivo testis toxicity for a variety of compounds and our novel in vitro model is able to capture toxicant perturbation of immune function.

The evaluation of possible role of endocrine disruptors in central and peripheral precocious puberty

Exposure to environmental chemicals can affect genetic and epigenetic molecular pathways and may cause altered growth and development. Among those exposures, endocrine-disrupting chemicals (EDCs) are of particular concern as humans are abundantly exposed to these chemicals by various means in every period of life. Several well-known environmental chemicals, including phthalates and bisphenol A (BPA), are classified as EDCs. These EDCs are suggested to play roles in early onset of puberty in girls. The aim of this study is to determine plasma phthalate (di(2-ethylhexyl)phthalate [DEHP] and its main metabolite mono(2-ethylhexyl)phthalate [MEHP]) and urinary BPA levels in girls with idiopathic central precocious puberty (CPP) and peripheral precocious puberty (PPP). This study was performed on newly diagnosed idiopathic central precocious puberty (CPP) patients (n = 42) and peripheral precocious puberty (PPP) (n = 42) patients, who were admitted to Keçiören Training and Research Hospital, Clinic of Pediatric Endocrinology between August 2012 and -July 2013. Nonobese healthy girls (n = 50) were used as the control group. Urinary BPA levels were not statistically different in control, PPP and CPP groups (medians 10.91, 10.63 and 10.15 μg/g creatinine, respectively; p > 0.05). Plasma DEHP levels were significantly higher in PPP group when compared to control. Plasma MEHP levels were not significantly different in control and PPP groups (p > 0.05). However, in CPP group, both plasma DEHP and MEHP levels were significantly higher than control and PPP groups. This study showed that phthalates might play a role in the occurence of CPP in girls.

Inhibitory mechanism of phthalate esters on Karenia brevis

The occurrence of phthalate esters (PAEs), a class of widely used and environmentally prevalent chemicals, raises concern to environmental and human health globally. The PAEs have been demonstrated to inhibit algae growth, but the underlying mechanisms remain unclear. In this research, diethyl ortho-phthalate (DEP), diallyl phthalate (DAP), di-n-butyl ortho-phthalate (DBP), di-iso-butyl ortho-phthalate, and benzyl-n-butyl ortho-phthalate (BBP) were screened from 11 species of PAEs to study their inhibitory effects on Karenia brevis and determine their target sites on algae. With increasing the alkyl chains of these five PAEs, the values of EC50,96h decreased. The content of malondialdehyde increased with the continuous accumulation of reactive oxygen species (ROS) in the algae cells. Moreover, the superoxide dismutase and catalase contents were first activated and then inhibited. The ultrastructures of Karenia brevis cells were detected by transmission electron microscopy, and cells treated with PAEs exhibiting distorted shapes and large vacuoles. Thus, the algae were damaged by ROS accumulation, resulting in lipid oxidation and algal growth inhibition. The inhibitors of the electron transport chain showed that the sites of ROS production and accumulation in K. brevis cells under DEP and BBP were the mitochondria and chloroplast, respectively. Moreover, the target sites of DAP and DBP were both the chloroplast and mitochondria. These results are useful for controlling PAEs contamination in and revealing the fate of PAEs in aquatic ecosystem.

Plasticizer endocrine disruption: Highlighting developmental and reproductive effects in mammals and non-mammalian aquatic species

Due to their versatility, robustness, and low production costs, plastics are used in a wide variety of applications. Plasticizers are mixed with polymers to increase flexibility of plastics. However, plasticizers are not covalently bound to plastics, and thus leach from products into the environment. Several studies have reported that two common plasticizers, bisphenol A (BPA) and phthalates, induce adverse health effects in vertebrates; however few studies have addressed their toxicity to non-mammalian species. The aim of this review is to compare the effects of plasticizers in animals, with a focus on aquatic species. In summary, we identified three main chains of events that occur in animals exposed to BPA and phthalates. Firstly, plasticizers affect development by altering both the thyroid hormone and growth hormone axes. Secondly, these chemicals interfere with reproduction by decreasing cholesterol transport through the mitochondrial membrane, leading to reduced steroidogenesis. Lastly, exposure to plasticizers leads to the activation of peroxisome proliferator-activated receptors, the increase of fatty acid oxidation, and the reduction in the ability to cope with the augmented oxidative stress leading to reproductive organ malformations, reproductive defects, and decreased fertility.

Occurrence, fate and effects of Di (2-ethylhexyl) Phthalate in wastewater treatment plants: a review

Phthalates, such as Di (2-ethylhexyl) Phthalate (DEHP) are compounds extensively used as plasticizer for long time around the world. Due to the extensive usage, DEHP is found in many surface waters (0.013-18.5 μg/L), wastewaters (0.716-122 μg/L), landfill leachate (88-460 μg/L), sludge (12-1250 mg/kg), soil (2-10 mg/kg). DEHP is persistent in the environment and the toxicity of the byproducts resulting from the degradation of DEHP sometime exacerbates the parent compound toxicity. Water/Wastewater treatment processes might play a key role in delivering safe, reliable supplies of water to households, industry and in safeguarding the quality of water in rivers, lakes and aquifers. This review addresses state of knowledge concerning the worldwide production, occurrence, fate and effects of DEHP in the environment. Moreover, the fate and behavior of DEHP in various treatment processes, including biological, physicochemical and advanced processes are reviewed and comparison (qualitative and quantitative) has been done between the processes. The trends and perspectives for treatment of wastewaters contaminated by DEHP are also analyzed in this review.

LC-TOF/MS determination of phthalates in edible salts from food markets in Korea

Residual quantities of 12 phthalates have been monitored in edible salts (raw salts, refined salts, refined salts with additives and baked salts) available in Korean food markets. Liquid-liquid extraction followed by liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS) was used to analyse the samples. The method was validated and showed linear correlation (R² > 0.996) in the range 0.5-100 ng g⁻¹ for all target analytes. Recoveries were 85.9-108.4%, except for diethyl phthalate (DEP). Relative standard deviations (RSDs) were 2.7-6.0% and the limits of detection (LODs) were 1.2-2.8 ng g⁻¹. Although the contamination of phthalates in salt would be trivial in comparison to those of other main foods and below the reference dose of the Chronic Oral Exposure recommended by US-EPA, the availability of reference data could be valuable for food chemists and salt manufacturers.

Sustainable and safe design of footwear integrating ecological footprint and risk criteria

The ecodesign of a product implies that different potential environmental impacts of diverse nature must be taken into account considering its whole life cycle, apart from the general design criteria (i.e. technical, functional, ergonomic, aesthetic or economic). In this sense, a sustainability assessment methodology, ecological footprint (EF), and environmental risk assessment (ERA), were combined for the first time to derive complementary criteria for the ecodesign of footwear. Four models of children's shoes were analyzed and compared. The synthetic shoes obtained a smaller EF (6.5 gm(2)) when compared to the leather shoes (11.1 gm(2)). However, high concentrations of hazardous substances were detected in the former, even making the Hazard Quotient (HQ) and the Cancer Risk (CR) exceed the recommended safety limits for one of the synthetic models analyzed. Risk criteria were prioritized in this case and, consequently, the design proposal was discarded. For the other cases, the perspective provided by the indicators of different nature was balanced to accomplish a fairest evaluation. The selection of fibers produced under sustainable criteria and the reduction of the materials consumption was recommended, since the area requirements would be minimized and the absence of hazardous compounds would ensure safety conditions during the use stage.

Assessing exposure to phthalates - the human biomonitoring approach

Some phthalates are developmental and reproductive toxicants in animals. Exposure to phthalates is considered to be potentially harmful to human health as well. Based on a comprehensive literature research, we present an overview of the sources of human phthalate exposure and results of exposure assessments with special focus on human biomonitoring data. Among the general population, there is widespread exposure to a number of phthalates. Foodstuff is the major source of phthalate exposure, particularly for the long-chain phthalates such as di(2-ethylhexyl) phthalate. For short-chain phthalates such as di-n-butyl-phthalate, additional pathways are of relevance. In general, children are exposed to higher phthalate doses than adults. Especially, high exposures can occur through some medications or medical devices. By comparing exposure data with existing limit values, one can also assess the risks associated with exposure to phthalates. Within the general population, some individuals exceed tolerable daily intake values for one or more phthalates. In high exposure groups, (intensive medical care, medications) tolerable daily intake transgressions can be substantial. Recent findings from animal studies suggest that a cumulative risk assessment for phthalates is warranted, and a cumulative exposure assessment to phthalates via human biomonitoring is a major step into this direction.

Biodegradation of a phthalate plasticizer, di-isononyl phthalate (DINP), by Sphingobium chungbukense

In this study, di-isononyl phthalate (DINP) was efficiently degraded by Sphingobium chungbukense KCTC 2955. The optimal conditions for DINP (100 mg L(-1)) degradation by S. chungbukense in a mineral salts medium were found to be pH 7.0, 30 degrees C, and stirring at 200 rpm. The maximum specific rate of DINP degradation was found to be concentration dependent, with a maximum of 4.12 mg DINP L(-1) h(-1). DINP was transformed rapidly by S. chungbukense, with the formation of monoisononyl phthalate (MIP) and phthalic acid, which subsequently degraded further. These results highlight the potential of this bacterium for removing DINP-contaminated waste in the environment.

Bacterial degradation of phthalate isomers and their esters

Phthalate isomers and their esters are used heavily in various industries. Excess use and leaching from the product pose them as major pollutants. These chemicals are toxic, teratogenic, mutagenic and carcinogenic in nature. Various aspects like toxicity, diversity in the aerobic bacterial degradation, enzymes and genetic organization of the metabolic pathways from various bacterial strains are reviewed here. Degradation of these esters proceeds by the action of esterases to form phthalate isomers, which are converted to dihydroxylated intermediates by specific and inducible phthalate isomer dioxygenases. Metabolic pathways of phthalate isomers converge at 3,4-dihydroxybenzoic acid, which undergoes either ortho- or meta- ring cleavage and subsequently metabolized to the central carbon pathway intermediates. The genes involved in the degradation are arranged in operons present either on plasmid or chromosome or both, and induced by specific phthalate isomer. Understanding metabolic pathways, diversity and their genetic regulation may help in constructing bacterial strains through genetic engineering approach for effective bioremediation and environmental clean up.

Baby care products: possible sources of infant phthalate exposure

OBJECTIVES

Phthalates are man-made chemicals found in personal care and other products. Recent studies suggest that some phthalates can alter human male reproductive development, but sources of infant exposure have not been well characterized. We investigated the relationship between phthalate metabolite concentrations in infant urine and maternal reported use of dermally applied infant care products.

METHODS

We measured 9 phthalate metabolites in 163 infants who were born in 2000-2005. An infant was considered to have been exposed to any infant care product that the mother reported using on her infant within 24 hours of urine collection. Results of multiple linear regression analyses are reported as the ratio of metabolite concentrations (with 95% confidence intervals) in exposed and unexposed infants. We standardized concentrations by forming z scores and examined combined exposure to multiple metabolites.

RESULTS

In most (81%) infants, > or = 7 phthalate metabolites were above the limit of detection. Exposure to lotion was predictive of monoethyl phthalate and monomethyl phthalate concentrations, powder of monoisobutyl phthalate, and shampoo of monomethyl phthalate. Z scores increased with number of products used. Most associations were stronger in younger infants.

CONCLUSIONS

Phthalate exposure is widespread and variable in infants. Infant exposure to lotion, powder, and shampoo were significantly associated with increased urinary concentrations of monoethyl phthalate, monomethyl phthalate, and monoisobutyl phthalate, and associations increased with the number of products used. This association was strongest in young infants, who may be more vulnerable to developmental and reproductive toxicity of phthalates given their immature metabolic system capability and increased dosage per unit body surface area.

Phthalate esters in human milk: concentration variations over a 6-month postpartum time

The present study investigated the levels of phthalate esters in a total of 86 human milk samples collected among 21 breast-feeding mothers over a 6-month postpartum time. Di(2-ethylhexyl) phthalate (DEHP) was the predominant ester with the arithmetic mean value of 222 ng g(-1) (range: 156-398 ng g(-1), 95% confidence limit), followed by dibutyl phthalate (DBP), 0.87 (range: 0.62-1.2) ng g(-1). Diethyl phthalate (DEP), with a mean of 0.31 ng g(-1), was detected in only a small number of samples. Weak correlations between lipid content and levels of phthalate esters were observed. The levels of phthalate esters in human milk fluctuated over the 6-month period; this may indicate a need for multiple sample collection, to calculate average concentrations over the feeding period. Multiple sample collection would provide a better estimate of the exposure of breast-fed infants to phthalate in human milk. For infants relying on breast-feeding, the mean daily intake over the first 6-month period considering a 7 kg infant consuming 750 g of milk was estimated at 167 microg d(-1) for DEHP and less than 1 microg d(-1) for DBP and DEP. While the nutritional and social benefits of breast-feeding are well established, the potential transfer of phthalate esters from mothers to breast-fed infants should also be recognized.

Urinary biomarkers of di-isononyl phthalate in rats

Commercial di-isononyl phthalate (DiNP) is a mixture of various branched-chain dialkyl phthalates mainly containing nine-carbon alkyl isomers. At high doses in rodents, DiNP is a carcinogen, and a developmental toxicant. After exposure, the diester isomers are de-esterified to form hydrolytic monoesters, monoisononyl phthalates (MiNP), which subsequently metabolize to form oxidative metabolites. These metabolites can be excreted in urine or feces. The urinary excretion of DiNP metabolites was monitored in adult female Sprague-Dawley rats after oral administration of a single dose (300 mg/kg) of commercial DiNP. The metabolites were extracted from urine, resolved with high performance liquid chromatography, analyzed by mass spectrometry, and tentatively identified based on their chromatographic separation and mass spectrometric fragmentation pattern. Because DiNP is an isomeric mixture, its metabolites were also isomeric mixtures that eluted from the HPLC column with close retention times. Mono(carboxy-isooctyl)phthalate (MCiOP) was identified as the major metabolite of DiNP; in addition, mono(hydroxy-isononyl)phthalate (MHiNP) and mono(oxo-isononyl)phthalate (MOiNP) were present. Furthermore, metabolites of di-isooctyl phthalate (DiOP) and di-isodecyl phthalate (DiDP) were also detected. Excretion toxicokinetics of the DiNP metabolites in urine followed a biphasic pattern with initial rapid decay in concentration. Despite potential differences in the metabolism of DiNP among species, MCiOP, MHiNP and MOiNP were detected in humans with no known exposure to DiNP at levels significantly higher than MiNP suggesting that these oxidative metabolites may be better urinary biomarkers of human exposure to DiNP than is MiNP.

Risk assessment of oral exposure to diisononyl phthalate from children's products

Dialkyl phthalates are plasticizers used in household products made from polyvinyl chloride (PVC). Diisononyl phthalate (DINP) is the principal phthalate in soft plastic toys. Because DINP is not tightly bound to PVC, it may be released when children mouth PVC products. The potential chronic health risks of phthalate exposure to infants have been under scrutiny by regulatory agencies in Europe, Canada, Japan, and the U.S. This report describes a risk assessment of DINP exposure from children's products, by the U.S. Consumer Product Safety Commission (CPSC) staff. This report includes the findings of a CPSC Chronic Hazard Advisory Panel (CHAP) which: (1) concluded that DINP is unlikely to present a human cancer hazard and (2) recommended an acceptable daily intake (ADI) level of 120 microg/kg-d, based on spongiosis hepatis in rats. The risk assessment incorporates new measurements of DINP migration rates from 24 toys and a new observational study of children's mouthing activities, with a detailed characterization of the objects mouthed. Probabilistic methods were used to estimate exposure. Mouthing behavior and, thus, exposure depend on the child's age. Approximately 42% of tested soft plastic toys contained DINP. Estimated DINP exposures for soft plastic toys were greatest among children 12-23 months old. The mean exposure for this age group was 0.08 (95% confidence interval 0.04-0.14) microg/kg-d, with a 99th percentile of 2.4 (1.3-3.2) microg/kg-d. The authors conclude that oral exposure to DINP from mouthing soft plastic toys is not likely to present a health hazard to children. The opinions expressed by the authors have not been reviewed or approved by, and do not necessarily reflect the views of, the U.S. Consumer Product Safety Commission. Because this material was prepared by the authors in their official capacity, it is in the public domain and may be freely copied or reprinted.

Interior and Interfacial Aqueous Solvation of Benzene Dicarboxylate Dianions and Their Methylated Analogues: A Combined Molecular Dynamics and Photoelectron Spectroscopy Study

Aqueous solvation of benzene dicarboxylate dianions (BCD(2-)) was studied by means of photoelectron spectroscopy and molecular dynamics simulations. Photoelectron spectra of hydrated o- and p-BCD(2-) with up to 25 water molecules were obtained. An even-odd effect was observed for the p-BCD(2-) system as a result of the alternate solvation of the two negative charges. However, the high polarizability of the benzene ring makes the two carboxylate groups interact with each other in p-BCD(2-), suppressing the strength of this even-odd effect compared with the linear dicarboxylate dianions linked by an aliphatic chain. No even-odd effect was observed for the o-BCD(2-) system, because each solvent molecule can interact with the two carboxylate groups at the same time due to their proximity. For large solvated clusters, the spectral features of the solute decreased while the solvent features became dominant, suggesting that both o- and p-BCD(2-) are situated in the center of the solvated clusters. Molecular dynamics simulations with both nonpolarizable and polarizable force fields confirmed that all three isomers (o-, m-, and p-BCD(2-)) solvate in the aqueous bulk. However, upon methylation the hydrophobic forces overwhelm electrostatic interactions and, as a result, the calculations predict that the tetramethyl-o-BCD(2-) is located at the water surface with the carboxylate groups anchored in the liquid and the methylated benzene ring tilted away from the aqueous phase.