Meta-analysis of environmental contamination by phthalates

Plastic additives as a new threat to the global environment: Research status, remediation strategies and perspectives

Discharge or leaching of plastic additives, which are an essential part of the plastic production process, can lead to environmental pollution with serious impacts on human and ecosystem health. Recently, the emission of plastic additives is increasing dramatically, but its pollution condition has not received enough attention. Meanwhile, the effective treatment strategy of plastic additive pollution is lack of systematic introduction. Therefore, it is crucial to analyze the harm and pollution status of plastic additives and explore effective pollution control strategies. This paper reviews the latest research progress on additives in plastics, describes the effects of their migration into packaged products and leaching into the environment, presents the hazards of four major classes of plastic additives (i.e., plasticizers, flame retardants, stabilizers, and antimicrobials), summarizes the existing abiotic/biotic strategies for accelerated the remediation of additives, and finally provides perspectives on future research on the removal of plastic additives. To the best of our knowledge, this is the first review that systematically analyzes strategies for the treatment of plastic additives. The study of these strategies could (i) provide feasible, cost-effective abiotic method for the removal of plastic additives, (ii) further enrich the current knowledge on plastic additive bioremediation, and (iii) present application and future development of plants, invertebrates and machine learning in plastic additive remediation.

Temporal evolution of plastic additive contents over the last decades in two major European rivers (Rhone and Rhine) from sediment cores analyses

Although global plastic distribution is at the heart of 21st century environmental concerns, little information is available concerning how organic plastic additives contaminate freshwater sediments, which are often subject to strong anthropogenic pressure. Here, sediment core samples were collected in the Rhone and the Rhine watersheds (France), dated using 137Cs and 210Pbxs methods and analysed for nine phthalates (PAEs) and seven organophosphate esters (OPEs). The distribution of these organic contaminants was used to establish a chronological archive of plastic additive pollution from 1860 (Rhine) and 1930 (Rhone) until today. Sediment grain size and parameters related to organic matter (OM) were also measured as potential factors that may affect the temporal distribution of OPEs and PAEs in sediments. Our results show that OPE and PAE levels increased continuously in Rhone and Rhine sediments since the first records. In both rivers, ∑PAEs levels (from 9.1 ± 1.7 to 487.3 ± 27.0 ng g-1 dry weight (dw) ± standard deviation and from 4.6 ± 1.3 to 65.2 ± 11.2 ng g-1 dw, for the Rhine and the Rhone rivers, respectively) were higher than ∑OPEs levels (from 0.1 ± 0.1 to 79.1 ± 13.7 ng g-1 dw and from 0.6 ± 0.1 to 17.8 ± 2.3 ng g-1 dw, for Rhine and Rhone rivers, respectively). In both rivers, di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAE, followed by diisobutyl phthalate (DiBP), while tris (2-chloroisopropyl) phosphate (TCPP) was the most abundant OPE. No relationship was found between granulometry and additives concentrations, while organic matter helps explain the vertical distribution of PAEs and OPEs in the sediment cores. This study thus establishes a temporal trajectory of PAEs and OPEs contents over the last decades, leading to a better understanding of historical pollution in these two Western European rivers.

The seasonal distribution of plasticizers in estuarine system: Controlling factors, storage and impact on the ecosystem

Plasticizers such as phthalate esters (PAEs) are commonly used in various consumer and industrial products. This widespread use raises valid concerns regarding their ubiquity in the environment and potential negative impacts. The present study investigates the distribution of eight common plasticizers in the largest European lagoon (Curonian Lagoon) located in the SE Baltic Sea. The concentration levels of plasticizers in the water column, containing both the dissolved and particulate-bound phases, and in sediments were evaluated to reveal seasonal patterns in distribution and potential effects on the lagoon ecosystem. A total of 24 water samples and 48 sediment samples were collected across all four seasons from the two dominant sedimentary areas within the lagoon. The average concentration of total PAEs in the water column ranged from 1 to 21 μg L-1, whereas sediment concentration varied from 5.0 to 250 ng g-1. The distribution of plasticizers was influenced by the patterns in hydrodynamics and water circulation within the lagoon. The confined south-central area contained a higher amount of PAEs in sediments, accounting for most of the lagoon's plasticizer accumulation. More than 7 tons of plasticizers are stored in the 5 upper centimetres of sediment, with over 3 tons persisting for more than five years. Di(2-ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DiBP), and Dibutyl phthalate (DnBP) were the most abundant PAE congeners, with DEHP posing the highest risk quotient to algae, based on water column concentration. Several other congeners demonstrated medium to high-risk levels for organisms living in the lagoon.

Coastal wastewater treatment plants as a source of endocrine disrupting micropollutants: a case study of Lithuania in the Baltic Sea

In temperate coastal areas, the resident population often increases during holidays. As a result, this can lead to higher wastewater production and release of pollutants. The connection between micropollutants such as plasticizers and hormones with the changing resident population along the Baltic Sea coast has yet to be thoroughly studied. Therefore, we have monitored the wastewater quality and specific micropollutants before and after treatment at wastewater treatment plants (WWTPs) at small and large seaside resorts. The findings indicate a strong link between tourism indicators and wastewater production during the summer months. The rise in different micropollutants, specifically plasticizers, during the summer demonstrates a link with tourism activity. Furthermore, we have identified a non-linear association between the tourism indicators and the total estrogenic equivalent (EEQ). Overall, this research particularly emphasizes the growing importance of wastewater quality in terms of conventional nutrient pollution and various micropollutants.

Association of co-exposure to polycyclic aromatic hydrocarbons and phthalates with oxidative stress and inflammation

Exposure to multiple environmental pollutants is ubiquitous and inevitable, but studies investigating their exposure effects on oxidative stress or inflammation have mainly been restricted to single-pollutant models. This study investigated the association of co-exposure to polycyclic aromatic hydrocarbons and phthalates with oxidative stress and inflammation. Using a cross-sectional study in adults, we measured urinary concentrations of metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) and phthalates (mPAEs), urinary oxidative stress biomarker 8-hydroxy-2'-deoxyguanosine, and 9 inflammatory biomarkers in paired blood samples. The associations of urinary OH-PAHs and mPAEs with oxidative stress and inflammation biomarkers were evaluated by different statistical models. The Bayesian kernel machine regression and quantile g-computation was used to examine the joint effects, and increased levels of urinary concentrations of OH-PAHs and mPAEs were associated with elevated 8-hydroxy-2'-deoxyguanosine level and white blood cell counts. Exposure to polycyclic aromatic hydrocarbons contributed more significantly to inflammation, while exposure to phthalates contributed more to oxidative stress. Monoisobutyl phthalate was identified as the most significant metabolite contributing to elevated oxidative stress levels. 1-Hydroxypyrene was negatively associated with platelet, and monomethyl phthalate was significantly positively associated with interleukin 6 in multivariate linear regression. The restricted cubic spline analysis revealed non-linear patterns of 3-hydroxyfluorene with white blood cell, lymphocyte, neutrophil, and C-reactive protein. The results indicated significant associations between increased co-exposure to polycyclic aromatic hydrocarbons and phthalates with elevated oxidative stress and inflammation. Further investigation is needed to elucidate the underlying biological mechanisms and to determine the potential public health implications.

A Review: Subcritical Water Extraction of Organic Pollutants from Environmental Matrices

Most organic pollutants are serious environmental concerns globally due to their resistance to biological, chemical, and photolytic degradation. The vast array of uses of organic compounds in daily life causes a massive annual release of these substances into the air, water, and soil. Typical examples of these substances include pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Since they are persistent and hazardous in the environment, as well as bio-accumulative, sensitive and efficient extraction and detection techniques are required to estimate the level of pollution and assess the ecological consequences. A wide variety of extraction methods, including pressurized liquid extraction, microwave-assisted extraction, supercritical fluid extraction, and subcritical water extraction, have been recently used for the extraction of organic pollutants from the environment. However, subcritical water has proven to be the most effective approach for the extraction of a wide range of organic pollutants from the environment. In this review article, we provide a brief overview of the subcritical water extraction technique and its application to the extraction of PAHs, PCBs, pesticides, pharmaceuticals, and others form environmental matrices. Furthermore, we briefly discuss the influence of key extraction parameters, such as extraction time, pressure, and temperature, on extraction efficiency and recovery.

Additives of plastics: Entry into the environment and potential risks to human and ecological health

A steep rise in global plastic production and significant discharge of plastic waste are expected in the near future. Plastics pose a threat to the ecosystem and human health through the generation of particulate plastics that act as carriers for other emerging contaminants, and the release of toxic chemical additives. Since plastic additives are not covalently bound, they can freely leach into the environment. Due to their occurrence in various environmental settings, the additives exert significant ecotoxicity. However, only 25% of plastic additives have been characterized for their potential ecological concern. Despite global market statistics highlighting the substantial environmental burden caused by the unrestricted production and use of plastic additives, information on their ecotoxicity remains incomplete. By focusing on the ecological impacts of plastic additives, the present review aims to provide detailed insights into the following aspects: (i) diversity and occurrence in the environment, (ii) leaching from plastic materials, (iii) trophic transfer, (iv) human exposure, (v) risks to ecosystem and human health, and (vi) legal guidelines and mitigation strategies. These insights are of immense value in restricting the use of toxic additives, searching for eco-friendly alternatives, and establishing or revising guidelines on plastic additives by global health and environmental agencies.

Reconnaissance Survey of Organic Contaminants of Emerging Concern in the Kabul and Swat Rivers of Pakistan

The Swat and Kabul rivers of northern Pakistan are within an important regional watershed that supports river-based livelihoods and is impacted by untreated effluent discharges and municipal solid waste. Evidence indicates that fish populations are decreasing in these rivers. One potential cause of poor aquatic health is pollution; therefore, we investigated the presence of contaminants of emerging concern (CECs) in the river systems. Water samples were collected in the Kabul River (n = 9) and Swat River (n = 10) during seasons of high (summer 2018) and low (winter 2019) river flow. Agrochemicals, pharmaceuticals, plasticizers, chemicals in personal care products, and hormones were quantified via liquid chromatography high-resolution mass spectrometry. In the Swat River, caffeine (18-8452 ng/L), N,N-diethyl-meta-toluamide (DEET; 16-56 ng/L), and plasticizers (13-7379 ng/L) were detected at all sites during both seasons, while butachlor (16-98 ng/L) was detected only during high flow. In the Kabul River, caffeine (12-2081 ng/L) and several plasticizers (91-722 ng/L) were detected at all sites during both seasons, while DEET (up to 97 ng/L) was detected only during high flow. During low flow, pharmaceuticals (analgesics and nonsteroidal anti-inflammatory drugs) were quantified in both rivers (up to 823 ng/L), with detection frequencies from 70% to 100% and 0% to 78% in the Swat and Kabul Rivers, respectively. Intermittent-use and natural seasonal processes (increased runoff and dilution from rainfall and snowmelt) yielded higher agrochemical concentrations and lower concentrations of continuous-use compounds (e.g., caffeine) during high flow. The present study provides the first insight into CEC concentrations in the Swat River, additional insight into the Kabul River stressors, and, overall, contaminant risks to aquatic life. Environ Toxicol Chem 2023;42:2599-2613. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Phthalate esters delivery to the largest European lagoon: Sources, partitioning and seasonal variations

Phthalate esters (PAEs) due to their ability to leach from plastics, widely used in our daily life, are intensely accumulating in wastewater water treatment plants (WWTP) and rivers, before being exported to downstream situated estuarine systems. This study aimed to investigate the external sources of eight plasticizers to the largest European lagoon (the Curonian Lagoon, south-east Baltic Sea), focusing on their seasonal variation and transport behaviour through the partitioning between dissolved and particulate phases. The obtained results were later combined with hydrological inputs at the inlet and outlet of the lagoon to estimate system role in regulating the transport of pollutants to the sea. Plasticizers were detected during all sampling events with a total concentration ranging from 0.01 to 6.17 μg L-1. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAEs and was mainly found attached to particulate matter, highlighting the importance of this matrix in the transport of such contaminant. Dibutyl phthalate (DnBP) and diisobutyl phthalate (DiBP) were the other two dominant PAEs found in the area, mainly detected in dissolved phase. Meteorological conditions appeared to be an important factor regulating the distribution of PAEs in environment. During the river ice-covered season, PAEs concentration showed the highest value suggesting the importance of ice in the retention of PAEs. While heavy rainfall impacts the amount of water delivered to WWTP, there is an increase of PAEs concentration supporting the hypothesis of their transport via soil leaching and infiltration into wastewater networks. Rainfall could also be a direct source of PAEs to the lagoon resulting in net surplus export of PAEs to the Baltic Sea.

Effects of Di-(2-Ethylhexyl) Phthalate (DEHP) on Gamete Quality Parameters of Male Koi Carp (Cyprinus carpio)

In this study, we evaluated gamete quality parameters of mature male koi carp (Cyprinus carpio) exposed to three different concentrations (1, 10, and 100 µg/L) of di-(2-ethylhexyl) phthalate (DEHP). After 60 days of exposure, there was a significant decrease in the gonadosomatic index (GSI) of males exposed to 10 and 100 µg/L of DEHP. Histological analysis of the testes revealed impaired histoarchitecture, including inflammatory cells, intratubular vacuoles, and swollen seminiferous tubules in treatment groups. Gamete quality parameters like sperm production, motility, spermatocrit, and sperm density values were significantly decreased at the 10 and 100 µg/L concentrations. Biochemical compositions, including glucose, cholesterol, and total protein levels, were significantly changed in the treatment groups. Similarly, the ionic compositions of seminal fluid (Na, K, Ca, and Mg) also varied in the treatment groups. Furthermore, the 11-ketotestosterone levels were decreased, and the 17-β estradiol levels were increased in the DEHP-treated groups. The mRNA expression levels of reproduction-related genes, including Fshr, Lhr, Ar, Erα, and Erβ, were significantly changed in the DEHP-treated males in a dose-dependent manner. In conclusion, the findings of this study confirmed that environmentally relevant exposure to DEHP may contribute to a decline in the gamete quality of male fishes.

Daphnia magna sub-lethal exposure to phthalate pollutants elicits disruptions in amino acid and energy metabolism

Phthalic acid esters (PAEs) are a class of chemicals that are usually incorporated as additives in the manufacturing of plastics. PAEs are not covalently bound to the material matrix and can, consequently, be leached into the environment. PAEs have been reported to act as endocrine disruptors, neurotoxins, metabolic stressors, and immunotoxins to aquatic organisms but there is a lack of information regarding the impact of sub-lethal concentrations to target organisms. The freshwater crustacean Daphnia magna, a commonly used model organism in aquatic toxicity, was exposed to four phthalate pollutants: dimethyl phthalate (DMP), diethyl phthalate (DEP), monomethyl phthalate (MMP), and monoethyl phthalate (MEP). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed in a targeted metabolomic approach to quantify polar metabolites extracted from a single Daphnia body. Individual metabolite percent changes and hierarchical clustering heatmap analysis showed unique metabolic profiles for each phthalate pollutant. Metabolite percent changes were mostly downregulated or presented opposing responses for the low and high concentrations tested. Meanwhile, pathway analyses suggest the disruption of related and unique pathways, mostly connected with amino acid and energy metabolism. The pathways aminoacyl-tRNA biosynthesis, arginine biosynthesis, and glutathione metabolism were disrupted by most selected PAEs. Overall, this study indicates that although phthalate pollutants can elicit distinct metabolic perturbations to each PAE, they still impacted related biochemical pathways. These chemical-class based responses could be associated with a common toxic mechanism of action. The reported findings show how targeted metabolomic approaches can lead to a better understanding of sub-lethal exposure to pollutants, revealing metabolomic endpoints do not hold a close relationship with traditional acute toxicity endpoints.

Non-persistent chemicals in polymer and non-polymer products can cause persistent environmental contamination: evidence with DEHP in Europe

Bis(2-ethylhexyl) phthalate (DEHP) is a plasticizer that has been massively used since the second part of the twentieth century by the plastic industry to provide softness properties to PVC. This chemical is considered as toxic to reproduction and endocrine disrupting, and a wide range of uses are now forbidden by the EU. Despite these regulations, DEHP is still found to be a widespread contaminant in watersheds in the EU. In this study, we calculate retrospective and prospective scenarios of past and future emissions of DEHP in the environment (water, soil, air) in the EU 28, taking into account the entire lifecycle of the substance, from its production and its inclusion in polymer (mainly PVC) and non-polymer products (adhesive and sealant, ceramic and printing ink) to the recycling and end of life of these products. We develop a stock and flow model based on dynamically estimating the stocks of DEHP present in products on the market. Our results show that the introduction of recent regulations to limit the use of DEHP (that bring a 70% reduction of DEHP contained in products placed on the market in 2020 and 75% in 2040) will not reduce significantly future emissions. This persistence of emissions is explained by the high stocks built in the economy and the long-term presence of soft PVC waste in landfills. Our results suggest that DEHP will remain a cause of environmental contamination many decades after uses have declined and even ceased, and it appears to be too late for market regulation at the market stage to offset the effect of past stock buildup and landfilling. It is likely that several chemicals that are not considered as persistent and therefore not the focus of international regulations could exhibit the same characteristics. Regulations should avoid possible use patterns that make hazardous chemicals persistent in products, because they have the potential to create long-term and almost irreversible environmental pollution and impacts.

DNA repair genes play a variety of roles in the development of fish embryos

Embryogenesis is one of the most important life stages because it determines an organism's healthy growth. However, embryos of externally fertilizing species, such as most fish, are directly exposed to the environment during development and may be threatened by DNA damaging factors (pollutants, UV, reactive oxygen species). To counteract the negative effects of DNA fragmentation, fish embryos evolved complex damage response pathways. DNA repair pathways have been extensively studied in some fish species, such as zebrafish (Danio rerio). Our literature review, on the other hand, revealed a paucity of knowledge about DNA damage response and repair in non-model aquaculture fish species. Further, several pieces of evidence underlie the additional role of DNA repair genes and proteins in organogenesis, spatiotemporal localization in different tissue, and its indispensability for normal embryo development. In this review, we will summarize features of different DNA repair pathways in course of fish embryo development. We describe how the expression of DNA repair genes and proteins is regulated during development, their organogenetic roles, and how the expression of DNA repair genes changes in response to genotoxic stress. This will aid in addressing the link between genotoxic stress and embryo phenotype. Furthermore, available data indicate that embryos can repair damaged DNA, but the effects of early-life stress may manifest later in life as behavioral changes, neoplasia, or neurodegeneration. Overall, we conclude that more research on DNA repair in fish embryos is needed.

Effects of aging on environmental behavior of plastic additives: Migration, leaching, and ecotoxicity

Microplastics (MPs), an emerging pollutant, are of global concern due to their wide distribution and large quantities. In addition to MPs themselves, various additives within MPs (such as plasticizers, flame retardants, antioxidants and heavy metals) may also have harmful effects on the environment. Most of these additives are physically bound to plastics and can therefore be leached from the plastic and released into the environment. Aging of MPs in the actual environment can affect the migration and release of additives, further increasing the ecotoxicological risk of additives to organisms. This work reviews the functions of several commonly used additives in MPs, and summarizes the representative characterization methods. Furthermore, the migration and leaching of additives in the human environment and marine environment are outlined. As aging promotes the internal chain breaking of MPs and the increase of specific surface area, it in turn stimulates the release of additives. The hazards of additive exposure have been elucidated, and various studies from the laboratory have shown that more toxic additives such as phthalates and brominated flame retardants can disrupt a variety of biological processes in organisms, including metabolism, skeletal development and so on. Increase of MPs ecological risk caused by the leaching of toxic additives is discussed, especially under the effect of aging. This study presents a systematic summary of various functional and environmental behaviors of additives in plastics, using weathering forces as the main factor, which helps to better assess the environmental impact and potential risks of MPs.

Occurrence, concentration, and distribution of 38 organic micropollutants in the filter material of 12 stormwater bioretention facilities

The increased use of bioretention facilities as a low impact development measure for treating stormwater runoff underscores the need to further understand their long-term function. Eventually, bioretention filter media must be (partly) replaced and disposed of at the end of its functional lifespan. While there are several studies of metal accumulation and distributions in bioretention media, less is known about organic pollutant pathways and accumulation in these filters. The present study considers the occurrence and accumulation of 16 polycyclic aromatic hydrocarbons, 7 polychlorinated biphenyls, 13 phthalates, and two alkylphenols throughout 12 older bioretention facilities (7-13 years old) used for stormwater treatment in Michigan and Ohio, USA. These pollutant groups appear to behave similarly, with greater instances of detection and higher concentrations in the upper media layers which decrease with increased depth from the surface. The patterns of detection and concentration in the filter material may be explained by characteristics of the pollutants, such as molecular structures and solubility that affect the removal of the organic pollutants by the filter material. There is also a large variation in concentration magnitudes between the bioretention sites, most likely due to differences in pollutant sources, contributing catchment size and/or land uses.

A global review of microplastics in wastewater treatment plants: Understanding their occurrence, fate and impact

Microplastics (MPs) are emerging as a serious environmental concern, with wastewater treatment plants (WWTPs) acting as the main entry routes for MPs into aquatic and terrestrial ecosystems. On a global scale, our literature review found that MP research in WWTPs has only been conducted on 121 WWTPs in 17 countries, with the majority of the work being done in Europe (53%), followed by the United States of America and Canada (24%), Asia (18%), and Australia (5%) in recent years. MPs in WWTPs are primarily derived from Personal Care and Cosmetic Products (PCCPs), which are primarily composed of polyethylene (PE) derivatives. Based on the studies, microfibers (57%) and fragments (47%) are observed to be the most common MP forms in influents and effluents of WWTPs. The chemical characterization of MPs detected in WWTPs, showed the occurrence of polyethylene (PE) (22%), polystyrene (PS) (21%), and polypropylene (13%). Although MP retention/removal efficiencies of different treatment technologies vary from medium to high, deliberations on sludge disposal on agricultural soils containing MPs and MP intrusion into groundwater are required to sustainably regulate MP contaminant transport. Thus, the development of efficient detection methods and understanding their fate are of immense significance for the management of MPs. Despite the fact that ongoing research in MPs and WWTPs has unquestionably improved our understanding, many questions and concerns remain unanswered. In this review, the current status of the detection, occurrence, and impact of MPs in WWTPs across the world are systematically reviewed to prioritize policy-making to recognize the WWTPs as global conduits of MPs.

Coupled Dynamic Material Flow, Multimedia Environmental Model, and Ecological Risk Analysis for Chemical Management: A Di(2-ethylhexhyl) Phthalate Case in China

Di(2-ethylhexhyl) phthalate (DEHP) is a widely used plasticizer that has adverse effects on ecosystems and human health. However, data about its stocks, flows, emission rates, as well as ecological risks are generally unknown in China, one of the world's largest producers of chemicals including DEHP, limiting sound management of chemicals. Herein, dynamic material flow analysis, coupled with a multimedia environmental model and ecological risk analysis, was performed to fill the data gap about DEHP in China mainland from 1956 to 2020. Results indicate that the in-use stocks of DEHP increased from 6.54 × 10⁶ kg in 1956 to 8.40 × 10⁹ kg in 2020. With growth in the emission rates, DEHP concentrations in air, soil, water, and sediment kept increasing from 1956 to 2010, which declined after 2010 and regrew after 2015. Sediment was a main sink of DEHP with the highest ecological risk quotient of >10 after 1999, necessitating measures for controlling the risk, for example, technology innovation to reduce DEHP emission rates, and substitution of DEHP with low-toxic alternatives. The coupled models that connect socio-economic data with ecological risk output may provide a systematic methodology for verification of the data necessary for risk control of chemicals.

Dibutyl phthalate-induced oxidative stress and apoptosis in swine testis cells and therapy of naringenin via PTEN/PI3K/AKT signaling pathway

Dibutyl phthalate (DBP) is a phthalic acid ester (PAE) that has posed a health hazard to the organisms. Naringenin (NRG) is a flavanone compound that has shown protection against several environmental chemicals through suppression of oxidative stress and activation of phosphatidylinositol 3-kinase/threonine kinase (PI3K/AKT) signaling pathway. Herein, swine testis (ST) cells were treated with 1.8 μM of DBP or/and 25.39 nM of NRG for 24 h, we described the discovery path of NRG inhibition on apoptosis in DBP-exposed ST cells through targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN). We first found that the anti-apoptosis effect of NRG is dependent on mitochondrial pathway through flow cytometry and related gene/protein expression, and then we detected PI3K/AKT pathway-related gene/protein expression, and established a computational docking assay between NRG and PTEN. We found that NRG specifically binds to three basic residues (His93, Lys125, Lys128) of P loop in PTEN, as well as phosphatase domains (Asp92, His93, Cys124, Lys125, Ala126, Lys128, and Arg130) in active dephosphorylation pockets, thereby reducing PTEN level and activating PI3K/AKT signaling pathway, and further inhibiting oxidative stress and mitochondrial pathway apoptosis. Taken together, our results push forward that NRG deserves further attention as a potential antagonistic therapy against DBP through targeting PTEN to inhibit oxidative stress and activate PI3K/AKT signaling pathway.

Simulated experimental investigation of microplastic weathering in marine environment

Microplastics act as a potential vector for a wide range of contaminants, which have emerged as a major environmental hazard in the modern world. Considering the seriousness of the problem, a simulated laboratory and field experiment were conducted to study the weathering of pristine microplastics following long-term exposure to natural background radiation and the marine environment after being disposed of in the open environment. For the study, polyethylene-originating (HDPE and LDPE) microplastics were chosen. The study revealed that radiation exposure causes surface roughness and cracks, leading to an increased surface area, which can invite a wide spectrum of pollutants to sorb on their surface. Furthermore, we report that the radiation-induced morphological changes favor microbial colonization on the microplastic surface when exposed to the marine environment. The growth of biofilms on the surface of microplastics reduces their hydrophobicity, which may attract a wide variety of polar contaminants. The study led to an interesting finding: that the HDPE microplastic surface is more conducive for biofilm growth in comparison to the LDPE surface.

Uptake of a plasticizer (di-n-butyl phthalate) impacts the biochemical and physiological responses of barley

BACKGROUND

DBP is one of the most commonly used plasticizers for imparting desirable properties to polymers. The introduction of phthalates is reported to have occurred in the late 1920s, and there has been a significant rise in their release into the environment in past decades due to a lack of covalent bonding with the parent matrix. Because of their numerous applications in day-to-day life, phthalates have become ubiquitous and also classified as endocrine disruptors. Hence, several studies have been conducted to investigate the phthalate-mediated toxicities in animals; however, plants have not been explored to the same amount.

METHODS

Therefore, in the present study, the accumulation and translocation along with morpho-physiological perturbations in barley plants after 15, 30, 60, and 120 days of exposure to di-n-butyl phthalate (DBP) are investigated using standard protocols.

RESULTS

The maximal accumulation and translocation of DBP in the roots and shoots of barley plants was observed after 60 days of exposure. The exposure of DBP from 15 to 120 days was recorded to decline all the morphological indices (i.e., dry weight, net primary productivity, seed number per spike, and seed weight) of barley plants. The pigments content declined under DBP treatment for all exposure durations except 120 days exposure. Carbohydrate content increased after 15-30 days of exposure afterward it was observed to be decreased under 60 and 120 days of exposure. The protein content was declined in DBP stressed plants for 15-120 days. Proline content was increased in all exposure durations and maximal percent increase was recorded in 120 days of exposure. MDA content showed an increase at earlier exposure durations then followed by a decline in long-term exposure. Hydrogen peroxide content increased at all exposure durations. There were significant alterations observed in the activities of all antioxidative enzymes in comparison to the control. Furthermore, DBP stressed plants after 60 days were analyzed for the macromolecular variations using Fourier transform infrared spectroscopy (FTIR).

CONCLUSION

Thus, the outcomes of the current work provide an appraisal of phthalates' uptake and translocation mediated phytotoxic responses in barley plants. These observations can help in developing genetically modified edible plants that are resistant to phthalates uptake, thereby ensuring food security.

Di-butyl phthalate (DBP) induces defects during embryonic eye development in zebrafish

Di-butyl phthalate (DBP) is a phthalate ester (PAEs) added during the manufacturing of plastics to make them stronger, yet more pliable. DBP is noncovalently bound to plastics resulting in leaching into the environment. Concerning concentrations of DBP have been noted in surface and groundwater, aquatic ecosystems, soil and atmospheric environments globally. Global production of phthalates and thus concomitant exposure has increased over the years making studies on the ecological and environmental safety needed. Most of the literature on DBP focuses on the endocrine disrupting properties of phthalate esters, but the developmental toxicity of DBP is an understudied area. Here, we treat gastrula staged zebrafish embryos with environmentally relevant concentrations of DBP (2.5 µM). We find defects in eye development at 96 h post fertilization including a decrease in the size of the lens and retina in DBP-treated embryos. Defects in eye vascularization as well as loss of the optic nerve and optic tectum were also noted. Here we conclude that exposure to environmentally relevant doses of DBP during early embryonic development is toxic to eye development.

Intrauterine exposure to di(2-ethylhexyl) phthalate (DEHP) disrupts the function of the hypothalamus-pituitary-thyroid axis of the F1 rats during adult life

INTRODUCTION

DEHP is an endocrine disruptor widely used in the production of malleable plastics. DEHP exposure was associated with altered hypothalamic-pituitary-thyroid (HPT) axis function. Although previous studies reported deleterious effects of DEHP exposure during the intrauterine period, few studies have evaluated the direct effects triggered by this endocrine disruptor on the offspring animals' thyroid function. This study aimed to investigate the impact of intrauterine exposure to DEHP on the HPT axis function programming of the offspring animals during adulthood.

METHODS

Pregnant Wistar rats were orally treated with corn oil or corn oil supplemented with DEHP (0.48 or 4.8 mg/kg/day) throughout the gestational period. The offspring rats were euthanized on the 90th postnatal day. Hypothalamus, pituitary, thyroid, and liver were collected to analyze gene expression and protein content through qPCR and Western Blot. Blood was collected to determine TSH and thyroid hormone levels through fluorometric or chemiluminescence immunoassays.

RESULTS

In the adult F1 female rats, the highest dose of DEHP decreased TSH serum levels. In the thyroid, DEHP reduced the gene expression and/or protein content of NIS, TSHR, TG, TPO, MCT8, NKX2.1, PAX8, and FOXE1. These data are consistent with the reduction in T4 serum levels of the F1 DEHP-exposed female rats. In the liver, DEHP exposure increased the mRNA expression of Dio1 and Ttr, while the highest dose of DEHP reduced the mRNA expression of Ugt1a1 and Ugt1a6. Conversely, in the F1 male adult rats, TSHB expression and TSH serum levels were increased in DEHP-exposed animals. In the thyroid, except for the reduced protein content of TSHR, none of the evaluated genes/proteins were altered by DEHP. TH serum levels were not changed in the DEHP-exposed F1 male rats compared to the control group. Additionally, there were no significant alterations in the expression of hepatic enzymes in these animals.

DISCUSSION/CONCLUSIONS

Our results demonstrated, for the first time, that intrauterine exposure to DEHP disrupts the HPT axis function in male and female offspring rats and strongly suggest that DEHP exposure increases the susceptibility of the offspring animals to develop thyroid dysfunctions during adulthood.

Impact of phthalates and bisphenols plasticizers on haemocyte immune function of aquatic invertebrates: A review on physiological, biochemical, and genomic aspects

The invertebrate innate immunity is a crucial characteristic that represents a valuable basis for studying common biological responses to environmental pollutants. Cell defence mechanisms are key players in protecting the organism from infections and foreign materials. Many haemocyte-associated immunological parameters have been reported to be immunologically sensitive to aquatic toxins (natural or artificial). Environmental plastic pollution poses a global threat to ecosystems and human health due to plastic vast and extensive use as additives in various consumer products. In recent years, studies have been done to evaluate the effects of plasticizers on humans and the environment, and their transmission and presence in water, air, and indoor dust, and so forth. Hence, the development of biomarkers that evaluate biological responses to different pollutants are essential to obtain important information on plasticizers' sublethal effects. This review analyses the current advances in the adverse effects of plasticizers (as emerging contaminants), such as immunological response disruption. The review also shows a critical analysis of the effects of the most widely used plasticizers on haemocytes. The advantages of an integrative approach that uses chemical, genetic, and immunomarker assays to monitor toxicity are highlighted. All these factors are imperative to ponder when designing toxicity studies to recognize the potential effects of plasticizers like bisphenol A and phthalates.

Remediation of Diethyl Phthalate in Aqueous Effluents with TiO2-Supported Rh0 Nanoparticles as Multicatalytic Materials

An innovative “domino” process, based on an arene hydrogenation followed by a photocatalytic step, was designed for the remediation of endocrine disrupting compounds, in highly concentrated aqueous effluents. The novelty relies on the use of TiO2-supported zerovalent Rh nanoparticles as multicatalytic materials (MCMs) for this two-step treatment, applied on diethyl phthalate, which is a model aromatic pollutant frequently present in aquatic environments. This nanocomposite advanced material, which was easily prepared by a green, wet impregnation methodology, proved to be active in the successive reactions, the reduction in the aromatic ring, and the photodegradation step. This sustainable approach offers promising alternatives in the case of photoresistive compounds.

Detrimental effects induced by diisononyl phthalate on development and behavior of Drosophila larva and potential mechanisms

Diisononyl phthalate (DINP) as one of the most commonly used phthalates, has been found in various environmental samples and is considered to have potential risks to ecosystem. Till now, DINP has no clear effect consensus on insects from development to behavior and even mechanisms. Here, Drosophila melanogaster was selected as model organisms and the toxic effects of DINP (0.1%, 0.2%, 0.5% and 1.0%) (v/v) on its metamorphosis, crawling behavior, intestinal cells and cellular redox balance were investigated. During metamorphosis process, lower hatching rate, longer development time, lighter body weight and malformation were observed at high concentration groups. The crawling ability of larvae was severely inhibited by DINP and the movement distance was drastically reduced. DINP could cause severe damage to the larval intestinal cells in the dose-dependent and time-dependent manners. DINP was found to induce redox imbalance with activities of two important antioxidant enzymes (catalase (CAT) and superoxide dismutase (SOD)) increasing, and reactive oxygen species (ROS) level fluctuation in larvae. Our findings provide theoretical basis and data support for scientific management of DINP to reduce ecological risk.

The oxidative stress responses caused by phthalate acid esters increases mRNA abundance of base excision repair (BER) genes in vivo and in vitro

The base excision repair (BER) pathway is an important defense response to oxidative DNA damage. It is known that exposures to phthalate esters (PAEs), including Dibutyl phthalate (DBP), Mono-(2-ethylhexyl) phthalate (MEHP), and Di-(2-ethylhexyl) phthalate (DEHP), cause reactive oxygen species-induced DNA damage and oxidative stress. Here, we determined the mRNA levels of BER pathway-related genes (ogg1, nthl1, apex1, parp1, xrcc1, lig3, ung, pcna, polb, pold, fen1, and lig1), pro-apoptotic gene (bax), and apoptotic suppressor gene (bcl2) in different PAEs-exposed zebrafish larvae and HEK293T cells. Further investigations were performed to examine reactive oxygen species (ROS) accumulation, superoxide dismutase (SOD) activity, developmental toxicity, and cell viability after PAEs exposure in vivo and in vitro. The results showed that PAEs exposure can induce developmental abnormalities in zebrafish larvae, and inhibit cell viability in HEK293T cells. Additionally, we found that PAEs exposure results in the accumulation of ROS and the inhibition of SOD activation in vivo and in vitro. Notably, the mRNA levels of BER pathway-related genes (OGG1, NTHL1, APEX1, XRCC1, UNG, POLB, POLD, FEN1) were significantly upregulated after DBP or MEHP exposure, whereas the mRNA levels of NTHL1, UNG, POLB, POLD, and FEN1 were significantly altered in DEHP-treated HEK293T cells. In zebrafish, the mRNA levels of ogg1, pcna, fen1 and lig1 genes were increased after DBP or DEHP exposure, whereas the mRNA levels of nthl1, apex1, parp1, lig3, pcna and polb were decreased after MEHP exposure, respectively. Thus, our findings indicated that PAEs exposure can induce developmental toxicity, cytotoxicity, and oxidative stress, as well as activate BER pathway in vivo and in vitro, suggesting that BER pathway might play critical roles in PAEs-induced oxidative stress through repairing oxidative DNA damage.

The Assessment of the Sewage and Sludge Contamination by Phthalate Acid Esters (PAEs) in Eastern Europe Countries

Phthalate acid esters (PAEs) are widely used as raw materials for industries that are well known for their environmental contamination and toxicological effects as “endocrine disruptors”. The determining of PAE contamination was based on analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), dicyclohexyl phthalate (DCHP) and di(2-ethylhexyl) phthalate (DEHP) in wastewater and sediment samples collected from city sewer systems of Lithuania and Poland, and Denmark for comparison. The potential PAE sources as well as their concentrations in the wastewater were analyzed and discussed. The intention of the study was to determine the level and key sources of pollution by phthalates in some Eastern European countries and to reveal the successful managerial actions to minimize PAEs taken by Denmark. Water and sludge samples were collected in 2019–2020 and analyzed by gas chromatography-mass spectrometry. The highest contamination with phthalates in Lithuania can be attributed to DEHP: up to 63% of total PAEs in water samples and up to 94% of total PAEs in sludge samples, which are primarily used as additive compounds to plastics but do not react with them and are gradually released into the environment. However, in water samples in Poland, the highest concentration belonged to DMP—up to 210 μg/L, while the share of DEHP reached 15 μg/L. The concentrations of priority phthalate esters in the water samples reached up to 159 μg/L (DEHP) in Lithuania and up to 1.2 μg/L (DEHP) in Denmark. The biggest DEHP concentrations obtained in the sediment samples were 95 mg/kg in Lithuania and up to 6.6 mg/kg in Denmark. The dominant compounds of PAEs in water samples of Lithuania were DEHP > DEP > DiBP > DBP > DMP. DPP and DCHP concentrations were less than 0.05 μg/L. However, the distribution of PAEs in the water samples from Poland was as follows: DMP > DEHP > DEP > DBP, and DiBP, as well as DPP and DCHP, concentrations were less than 0.05 μg/L. Further studies are recommended for adequate monitoring of phthalates in wastewater and sludge in order to reduce or/and predict phthalates’ potential risk to hydrobiots and human health.

Effects of Di-Isononyl Phthalate (DiNP) on Follicular Atresia in Zebrafish Ovary

Di-isononyl phthalate (DiNP) is a plasticizer reported to elicit hormone-like activity and disrupt metabolism and reproduction in fish and other vertebrates. In general, phthalates have been used at high concentrations beyond reported environmental levels to assess their adverse effects on fish gonadal physiology. The present study exposed adult female zebrafish to a wide range of DiNP concentrations [0.42 µg L^-1 (10^-9 M), 4.2 µg L^-1 (10^-8 M), and 42 µg L^-1 (10^-7 M)] for 21 days. We evaluated gene expression profiles related to apoptosis, autophagy, and oxidative stress; DNA fragmentation (TUNEL assay: terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase activity (CAS3) were also examined. Exposure to 0.42 and 4.2 µg L^-1 upregulated the genes coding for tnfa and baxa, sod1, prkaa1, respectively. CAS3 immunohistochemistry revealed a higher number of positive vitellogenic oocytes in ovaries exposed to 0.42 µg L^-1. Subsequently, we examined the relationship between CAS3 signaling and DNA fragmentation. Accordingly, DNA fragmentation was observed in vitellogenic follicles of fish exposed to 0.42 and 4.2 μg L^-1. Our results demonstrate that follicular atresia can occur after exposure to environmental levels of DiNP for 21 days, which may adversely affect the reproductive performance of female zebrafish in a non-monotonic manner.

Effects of Environment and Lifestyle Factors on Premature Ovarian Failure

Premature ovarian insufficiency (POI) or primary ovarian failure is defined as a cessation of the menstrual cycle in women younger than 40 years old. It is strictly defined as more than 4 months of oligomenorrhea or amenorrhea in a woman <40 years old, associated with at least two follicle-stimulating hormone (FSH) levels >25 U/L in the menopausal range, detected more than 4 weeks apart. It is estimated that POI was affected 1 and 2% of women. Although 80% of POI cases are of unknown etiology, it is suggested that genetic disorder, autoimmune origin, toxins, and environmental factors, as well as personal lifestyles, may be risk factors of developing POI. In this section, we will discuss the influences of environmental and lifestyle factors on POI. Moreover updated basic research findings regarding how these environmental factors affect female ovarian function via epigenetic regulations will also be discussed.

Perinatal DEHP exposure induces sex- and tissue-specific DNA methylation changes in both juvenile and adult mice

Di(2-ethylhexyl) phthalate (DEHP) is a type of phthalate plasticizer found in a variety of consumer products and poses a public health concern due to its metabolic and endocrine disruption activities. Dysregulation of epigenetic modifications, including DNA methylation, has been shown to be an important mechanism for the pathogenic effects of prenatal exposures, including phthalates. In this study, we used an established mouse model to study the effect of perinatal DEHP exposure on the DNA methylation profile in liver (a primary target tissue of DEHP) and blood (a common surrogate tissue) of both juvenile and adult mice. Despite exposure ceasing at 3 weeks of age (PND21), we identified thousands of sex-specific differential DNA methylation events in 5-month old mice, more than identified at PND21, both in blood and liver. Only a small number of these differentially methylated cytosines (DMCs) overlapped between the time points, or between tissues (i.e. liver and blood), indicating blood may not be an appropriate surrogate tissue to estimate the effects of DEHP exposure on liver DNA methylation. We detected sex-specific DMCs common between 3-week and 5-month samples, pointing to specific DNA methylation alterations that are consistent between weanling and adult mice. In summary, this is the first study to assess the genome-wide DNA methylation profiles in liver and blood at two different aged cohorts in response to perinatal DEHP exposure. Our findings cast light on the implications of using surrogate tissue instead of target tissue in human population-based studies and identify epigenetic biomarkers for DEHP exposure.

Exposure evaluation of diisononyl phthalate in the adults of Drosophila melanogaster: Potential risks in fertility, lifespan, behavior, and modes of action

Diisononyl phthalate (DINP) as a phthalate plasticizer is widely used in daily life and production, which shows endocrine disruption effects and has several adverse effects on the normal physiological function. Here, the effects of DINP (0.1%, 0.2%, 0.5%, and 1.0%) (v/v) on the fertility, lifespan, climbing behavior, anti-starvation ability of Drosophila melanogaster and the potential modes of action were investigated. The results showed that DINP impaired fertility in a dose-dependent manner and smaller ovarian volume, lower hatching rate, and fewer offspring was observed at higher concentrations. The effect of DINP on the lifespan showed gender-specific, and mortality was increased after exposure above 0.2% DINP. The climbing ability increased at 0.1% DINP compared with the vehicle group, while it manifested a dose-dependent decrease at higher concentrations. The anti-starvation ability exhibited hormesis after short-term culture and reduced as culture time extending. By measuring the redox status (catalase (CAT) and reactive oxygen species (ROS)) of adult flies after two exposure methods, it was found that DINP induced redox instability, which may explain the above effects at the molecular level. This study provides data to support a comprehensive analysis of DINP potential toxicity and to guide its rational use and management better.

A Visual Leaf Zymography Technique for the In Situ Examination of Plant Enzyme Activity under the Stress of Environmental Pollution

This study established a high-efficiency fluorescence quenching approach for the in situ visualization and modeling of the spatial distribution of xylanase, β-glucosidase, and phosphatase activities in plant leaves under pollution stress (namely, the leaf zymography technique, LZT). In the LZT, a membrane saturated with an enzyme-specific fluorescent substrate on the leaf surface was incubated and the fluorescence image generated on the membrane under ultraviolet light was recorded. An image-based modeling method for restoring the morphological traits of the true image by reducing noise was developed to ensure the accurate estimation of enzyme activities. The LZT could simultaneously measure 48 samples within 2 h, with good reproducibility. The results obtained by the LZT were comparable to those obtained by a conventional biochemical analysis method and presented low-cost and convenient advantages. This paper explains the theoretical basis required to investigate the realistic application of the LZT for assessing ecotoxicity in large-scale monitoring.

A Relevant Screening of Organic Contaminants Present on Freshwater and Pre-Production Microplastics

Microplastics (MPs) have recently been discovered as considerable pollutants of all environmental matrices. They can contain a blend of chemicals, some of them added during the manufacture of plastic to improve their quality (additives) and others adsorbed from the surrounding environment. In light of this, a detailed study about the identification and quantification of target organic pollutants and qualitative screening of non-target compounds present on MPs was carried out in different types of samples: environmental MPs, collected from an Italian river, and pre-production MPs, taken from the plastic industry. Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs) were chosen as target compounds to be quantified by Gas Chromatography-Mass Spectrometry (GC–MS), while the non-target screening was carried out by High Resolution Gas Chromatography-Mass Spectrometry (HRGC–MS). The target analysis revealed concentrations of 16 priority Polycyclic Aromatic Hydrocarbons by Environmental Protection Agency (EPA-PAHs) in the range of 29.9–269.1 ng/g; the quantification of 31 PCBs showed values from 0.54 to 15.3 ng/g, identifying CB-138, 153, 180, 52, and 101 primarily; and the detected OCPs (p,p’-DDT and its metabolites) ranged between 14.5 and 63.7 ng/g. The non-target screening tentatively identified 246 compounds (e.g., phthalates, antioxidants, UV-stabilizers), including endocrine disruptors, toxic and reprotoxic substances, as well as chemicals subjected to risk assessment and authorisation. The large assortment of plastic chemicals associated with MPs showed their role as a presumable source of pollutants, some of which might have high bioaccumulation potential, persistence, and toxicity.

Updates on molecular and environmental determinants of luteal progesterone production

Progesterone, a critical hormone in reproduction, is a key sex steroid in the establishment and maintenance of early pregnancy and serves as an intermediary for synthesis of other steroid hormones. Progesterone production from the corpus luteum is a tightly regulated process which is stimulated and maintained by multiple factors, both systemic and local. Multiple regulatory systems, including classic mediators of gonadotropin stimulation such as the cAMP/PKA pathway and TGFβ-mediated signaling pathways, as well as local production of hormonal factors, exist to promote granulosa cell function and physiological fine-tuning of progesterone levels. In this manuscript, we provide an updated narrative review of the known mediators of human luteal progesterone and highlight new observations regarding this important process, focusing on studies published within the last five years. We will also review recent evidence suggesting that this complex system of progesterone production is sensitive to disruption by exogenous environmental chemicals that can mimic or interfere with the activities of endogenous hormones.

Effects of DEHP on the ecdysteroid pathway, sexual behavior and offspring of the moth Spodoptera littoralis

Bis(2-ethylhexyl) phthalate (DEHP) is a widely produced plasticizer that is considered to act as an endocrine-disrupting chemical in vertebrates and invertebrates. Indeed, many studies have shown that DEHP alters hormonal levels, reproduction and behavior in vertebrates. Few studies have focused on the effects of DEHP on insects, although DEHP is found almost everywhere in their natural habitats, particularly in soils and plants. Here, we investigated the effects of DEHP on the sexual behavior and physiology of a pest insect, the noctuid moth Spodoptera littoralis. In this nocturnal species, olfaction is crucial for sexual behavior, and ecdysteroids at the antennal level have been shown to modulate sex pheromone detection by males. In the present study, larvae were fed food containing different DEHP concentrations, and DEHP concentrations were then measured in the adults (males and females). Hemolymphatic ecdysteroid concentrations, the antennal expression of genes involved in the ecdysteroid pathway (nuclear receptors EcR, USP, E75, and E78 and calmodulin) and sexual behavior were then investigated in adult males. The success and latency of mating as well as the hatching success were also studied in pairs consisting of one DEHP male and one uncontaminated female or one DEHP female and one uncontaminated male. We also studied the offspring produced from pairs involving contaminated females to test the transgenerational effect of DEHP. Our results showed the general downregulation of nuclear receptors and calmodulin gene expression associated with the higher concentrations of DEHP, suggesting peripheral olfactory disruption. We found some effects on male behavior but without an alteration of the mating rate. Effects on offspring mortality and developmental rates in the N + 1 generation were also found at the higher doses of DEHP. Taken together, the results of the study show for the first time that larval exposure to DEHP can induce delayed endocrine-disruptive effects in the adults of a terrestrial insect as well as effects on the next generation. To date, our study is also the first description of an impact of endocrine disrupter on olfaction in insects.

Effect of environmental contamination on female and male gametes - A lesson from bovines

Endocrine-disrupting compounds (EDCs) and foodborne contaminants are environmental pollutants that are considered reproductive toxicants due to their deleterious effects on female and male gametes. Among the EDCs, the phthalate plasticizers are of growing concern. In-vivo and in-vitro models indicate that the oocyte is highly sensitive to phthalates. This review summarizes the effects of di(2-ethylhexyl) phthalate and its major metabolite mono(2-ethyhexyl) phthalate (MEHP) on the oocyte. MEHP reduces the proportion of oocytes that fertilize, cleave and develop to the blastocyst stage. This is associated with negative effects on meiotic progression, and disruption of cortical granules, endoplasmic reticulum and mitochondrial reorganization. MEHP alters mitochondrial membrane polarity, increases reactive oxygen species levels and induces alterations in genes associated with oxidative phosphorylation. A carryover effect from the oocyte to the blastocyst is manifested by alterations in the transcriptomic profile of blastocysts developed from MEHP-treated oocytes. Among foodborne contaminants, the pesticide atrazine (ATZ) and the mycotoxin aflatoxin B1 (AFB1) are of high concern. The potential hazards associated with exposure of spermatozoa to these contaminants and their carryover effect to the blastocyst are described. AFB1 and ATZ reduce spermatozoa's viability, as reflected by a high proportion of cells with damaged plasma membrane; induce acrosome reaction, expressed as damage to the acrosomal membrane; and interfere with mitochondrial function, characterized by hyperpolarization of the membrane. ATZ and AFB1-treated spermatozoa show a high proportion of cells with fragmented DNA. Exposure of spermatozoa to AFB1 and ATZ reduces fertilization and cleavage rates, but not that of blastocyst formation. However, fertilization with AFB1- or ATZ-treated spermatozoa impairs transcript expression in the formed blastocysts, implying a carryover effect. Taken together, the review indicates the risk of exposing farm animals to environmental contaminants, and their deleterious effects on female and male gametes and the developing embryo.

The association between environmental endocrine disruptors and cardiovascular diseases: A systematic review and meta-analysis

BACKGROUND

Except for known cardiovascular risk factors, long-term exposure to environmental endocrine disruptors (EEDs) - a class of exogenous chemicals, or a mixture of chemicals, that can interfere with any aspect of hormone action - has been shown to increase the risk of cardiovascular diseases (CVDs), which are still controversial.

OBJECTIVE

To conduct a comprehensive systematic review and meta-analysis to estimate the association between EEDs, including nonylphenol (NP), bisphenol A (BPA), polychlorinated biphenyl (PCB), organo-chlorine pesticide (OCP) and phthalate (PAE) exposure and CVD risk.

METHODS

The heterogeneity between different studies was qualitatively and quantitatively evaluated using Q test and I² statistical magnitude, respectively. Subgroup analysis was performed using chemical homologs - a previously unused grouping method - to extract data and perform meta-analysis to assess their exposure to CVD.

RESULTS

Twenty-nine literatures were enrolled with a total sample size of 88891. The results indicated that exposure to PCB138 and PCB153 were the risk factors for CVD morbidity (odds ratio (OR) = 1.35, 95% confidence interval (CI): 1.10-1.66; OR = 1.35, 95% CI: 1.13-1.62). Exposure to organo-chlorine pesticide (OCP) (OR = 1.12, 95% CI: 1.00-1.24), as well as with phthalate (PAE) (OR = 1.11, 95% CI: 1.06-1.17) and BPA (OR = 1.19, 95% CI: 1.03-1.37) were positively associated with CVD risk, respectively. BPA exposure concentration had no correlation with total cholesterol (TC), or low-density lipoprotein (LDL), but exhibited a correlation with gender, waist circumference (WC), high-density lipoprotein (HDL), age, and body mass index (BMI) (standardized mean difference (SMD)) = 1.51; 95% CI: =(1.01-2.25); SMD = 0.16; 95% CI: (0.08-0.23); SMD = -0.19; 95% CI: (-0.27-0.12); SMD = -0.78; 95% CI: (-1.42-0.14); SMD = 0.08; 95% CI: (0.00-0.16).

CONCLUSIONS

EED exposure is a risk factor for CVD. Long-term exposure to EEDs can influence cardiovascular health in humans. A possible synergistic effect may exist between the homologs. The mechanism of which needs to be further explored and demonstrated by additional prospective cohort studies, results of in vitro and in vivo analyses, as well as indices affecting CVD.

Distribution and risk assessment of phthalates in water and sediment of the Pearl River Delta

Phthalate esters (PAEs) are widely used industrial raw materials that are well known for their environmental contamination and toxicological effects as "endocrine disruptors." In this study, environmental levels of PAEs and eco-toxicological risk assessments were determined in the eight estuaries of the Pearl River (Estuaries), main upstream tributary (Xijiang River), urban river network (River network), and nature reserve reservoir (Reservoirs). Water and sediment samples from the above water systems were collected during the low-water period (May) and the high-water period (August) between 2012 and 2014. Solid phase and ultrasonic methods were used to extract 14 different PAEs that were analyzed by gas chromatography. The analytical average recovery of PAEs in water and sediment was 75.4% ± 4.9% and 121.5% ± 8.9%, respectively. The results showed that PAEs were detected in all of the samples, and the di-n-butyl phtalate (DBP) and benzyl butyl phthalate (BBP) monomers had a detection rate of 100% in water. Similarly, in sediment samples, the detection rates of diisobutyl phthalate (DiBP), DBP, dimethoxyethyl phthalate (DMEP), BBP, di-n-octyl phthalate (DnOP), and DNP ranged from 66.7 to 100%. Among these, in sediment samples, di(2-ethylhexyl) phthalate (DEHP) and phthalic acid bis(2-butoxyethyl) ester (DBEP) had detection rates of 95.8% to 100% in the Estuaries, Xijiang River, and River network. The concentrations of Σ₁₄PAEs in water samples and sediments ranged from 12.95 ± 1.97 to 6717.29 ± 112.37 ng/L and 71.99 ± 8.72 to 17,340.04 ± 227.83 ng/g-dw, respectively. During the low-water period, the average concentration of Σ₁₄PAEs in water and sediment was 1159.58 ± 97.22 ng/L and 2842.50 ± 178.21 ng/g-dw, respectively, and during the high-water period, 822.83 ± 53.19 ng/L and 1936.42 ± 111.31 ng/g-dw, respectively. In water, the average concentration of Σ₁₄PAEs in 2013 and 2014 was 963.39 ± 19.55 ng/L and 2815.35 ± 176.32 ng/L, respectively. In sediment, the average concentrations of Σ₁₄PAEs in 2012 to 2014 were 990.10 ± 23.33 ng/g-dw, 1084.20 ± 112.12 ng/g-dw, and 1816.89 ± 79.97 ng/g-dw, respectively, with concentrations showing an increasing trend year after year (2014 > 2013 > 2012). Potential risk assessment of water ecological, the results show that exceeding environmental risk level (ERL) value in higher molecular weight plasticizer (DEHP, DMEP, DNOP, DNP) was mainly distributed in water, the lower molecular weight plasticizer (BMP, DiBP) was mainly distributed in sediment.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Prenatal exposure to a phthalate mixture leads to multigenerational and transgenerational effects on uterine morphology and function in mice

Phthalates are commonly used plasticizers and additives that are found in plastic containers, children's toys and medical equipment. Phthalates are classified as endocrine-disrupting chemicals and exposure to phthalates has been associated with several human health risks including reproductive defects. Most studies focus on a single phthalate; however, humans are exposed to a mixture of phthalates daily. We hypothesized that prenatal exposure to an environmentally relevant phthalate mixture would lead to changes in uterine morphology and function in mice in a multi-generational manner. To test this hypothesis, pregnant CD-1 dams were orally dosed with vehicle or a phthalate mixture (20 μg/kg/day, 200 μg/kg/day, 200 mg/kg/day, and 500 mg/kg/day) from gestational day 10.5 to parturition. The mixture contained 35 % diethyl phthalate, 21 % di-(2-ethylhexyl) phthalate, 15 % dibutyl phthalate, 15 % diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. The F1 pups were maintained and mated to produce two more generations (F2 and F3). At the age of 13 months, all females were euthanized and tissue samples were collected in diestrus. Our results showed that exposure to a phthalate mixture caused a decrease in progesterone levels in the treated groups in the F2 generation. The 200 mg/kg/day treatment group showed a decreased and increased luminal epithelial cell proliferation in the F1 and F2 generations respectively. In addition, these mice in the F2 generation had reduced Hand2 expression in the sub-epithelial stroma compared to the controls. A higher incidence of multilayered luminal epithelium and large dilated endometrial glands were observed in the phthalate mixture exposed groups in all generations. The mixture also caused a higher incidence of smooth muscle actin expression and collagen deposition in the endometrium compared to controls. Collectively, our results demonstrate that prenatal exposure to an environmentally relevant phthalate mixture can have adverse effects on female reproductive functions.

A Detailed Review Study on Potential Effects of Microplastics and Additives of Concern on Human Health

The distribution and abundance of microplastics into the world are so extensive that many scientists use them as key indicators of the recent and contemporary period defining a new historical epoch: The Plasticene. However, the implications of microplastics are not yet thoroughly understood. There is considerable complexity involved to understand their impact due to different physical-chemical properties that make microplastics multifaceted stressors. If, on the one hand, microplastics carry toxic chemicals in the ecosystems, thus serving as vectors of transport, they are themselves, on the other hand, a cocktail of hazardous chemicals that are added voluntarily during their production as additives to increase polymer properties and prolong their life. To date, there is a considerable lack of knowledge on the major additives of concern that are used in the plastic industry, on their fate once microplastics dispose into the environment, and on their consequent effects on human health when associated with micro and nanoplastics. The present study emphasizes the most toxic and dangerous chemical substances that are contained in all plastic products to describe the effects and implications of these hazardous chemicals on human health, providing a detailed overview of studies that have investigated their abundance on microplastics. In the present work, we conducted a capillary review of the literature on micro and nanoplastic exposure pathways and their potential risk to human health to summarize current knowledge with the intention of better focus future research in this area and fill knowledge gaps.

Transcriptomic analysis reveals potential mechanisms of toxicity in a combined exposure to dibutyl phthalate and diisobutyl phthalate in zebrafish (Danio rerio) ovary

Phthalate esters (PAEs), which are notable plasticizers, can be prolific contaminants in aquatic environments, and have been shown to induce reproductive toxicity. However, the studies concerning their toxicity towards aquatic species are based on individual chemicals, and the combined toxicity of PAEs to aquatic organisms remains unclear. The aim of this study was to explore the potential toxicity mechanisms associated with combined exposure to dibutyl phthalate (DBP) and diisobutyl phthalate (DiBP) in adult female zebrafish ovaries. Zebrafish were exposed to DBP, DiBP and their mixtures for 30 days, and their effects on ovarian histology, plasma sex hormones and ovarian transcriptomics were investigated. Plasma estradiol (E2) levels were significantly decreased by 38.9% in the DBP-1133 exposure group and 41.0% in the DiBP-1038 exposure group. The percentage of late/mature oocytes was also significantly decreased by 17.3% under DBP-1133 exposure and 16.2% under DiBP-1038 exposure, while that under combined exposure was not significantly affected. Nevertheless, transcriptome sequencing revealed 2564 differentially expressed genes (DEGs) in zebrafish ovaries after exposure to the mixtures. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the DEGs were involved in the neuroactive ligand-receptor interaction, GnRH, progesterone-mediated oocyte maturation, oocyte meiosis and steroid hormone biosynthesis signaling pathways. These results revealed that combined exposure exerts potential reproductive toxicity at the molecular level.

The relationships between urinary phthalate metabolites, reproductive hormones and semen parameters in men attending in vitro fertilization clinic

Evidence from previous studies has shown that phthalates may play a role in male reproductive function; however, results are still inconclusive, and the mechanism remains unclear. In this study, we first assessed whether exposure to phthalates is associated with altered reproductive hormones and semen parameters in 599 men attending an in vitro fertilization clinic. Secondly, we evaluated whether reproductive hormones could play a mediating role in the association between phthalates and sperm parameters. Eight phthalate metabolites were measured in two different spot urine samples: mono‑n‑butyl phthalate, mono-isobutyl phthalate (MiBP), monoethyl phthalate (MEP), monobenzyl phthalate, and four oxidative metabolites of di‑(2‑ethylhexyl) phthalate (DEHP) [i.e., mono‑(2‑ethylhexyl) phthalate (MEHP), mono‑(2‑ethyl‑5‑hydroxyhexyl) phthalate (MEHHP), mono‑(2‑ethyl‑5‑oxohexyl) phthalate (MEOHP), and mono‑(2‑ethyl‑5‑carboxypentyl) phthalate (MECPP)]. Semen parameters (concentration, volume, motility, and morphology) and reproductive hormones, i.e., follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone, estradiol (E₂), testosterone (TEST) and prolactin (PROL) were also determined and considered the main study outcomes. Separate multivariate linear regression was used to assess associations between levels of each urinary phthalate metabolite, molar sum of DEHP metabolites (∑DEHP), percentage of MEHP to ∑DEHP (%MEHP), and each outcome (natural log-transformed). Inverse associations were observed between TEST and MiBP (β = -0.099), FSH and MEHHP (β = -0.087), and PROL and MEOHP (β = -0.102), while a positive relationship was seen between E₂ and MEP (β = 0.098). %MEHP was associated positively with FSH (β = 0.118) and LH (β = 0.099), but negatively with TEST/LH (β = -0.086) and TEST/E₂ (β = -0.109). Sperm concentration was associated positively with MECPP (β = 0.131), MEHHP (β = 0.117), MEOHP (β = 0.107) and ∑DEHP (β = 0.111), but negatively with %MEHP (β = -0.135). All p-values were <0.05. Sobel's test indicated that FSH mediated significantly up to 60% of the positive relationship between sperm concentration and MEHHP, while FSH and LH mediated respectively 15 and 12% of the inverse association between sperm concentration and %MEHP. Further research on this topic is warranted.

Effects of diisononyl phthalate (DiNP) on the endocannabinoid and reproductive systems of male gilthead sea bream (Sparus aurata) during the spawning season

Diisononyl phthalate (DiNP) is a plasticizer used to improve plastic performance in a large variety of items which has been reported as an endocrine-disrupting chemical (EDC) in several organisms. The endocannabinoid system (ECS) is a cellular signaling system, whose functionality is tightly involved with reproductive function. The aim of the present study was the assessment of the effects of DiNP on the gonadal ECS and on the reproductive function of male gilthead sea bream Sparus aurata, an important marine aquacultured species in Europe, during the reproductive season. Fish were fed for 21 days with two diets contaminated with different nominal concentrations of DiNP (DiNP LOW at 15 µg DiNP kg^-1 bw day^-1 and DiNP HIGH at 1500 µg DiNP kg^-1 bw day^-1), based on the tolerable daily intake (TDI) ruled by the European Food Safety Authority for humans. The transcription of several genes related to the ECS was affected by the DiNP. Specifically, DiNP reduced the levels of endocannabinoids and endocannabinoid-like mediators, concomitant with the increase of fatty acid amide hydrolase (FAAH) activity. At the histological level, DiNP LOW induced the highest occurrence of individuals with regressed testes. Steroidogenesis was affected significantly, since plasma 11-ketotestosterone (11-KT), the main active androgen in fish, was significantly decreased by the DiNP HIGH treatment, while plasma 17β-estradiol (E₂) levels were raised, associated with an increase of the gonadosomatic index (GSI). Additionally, the level of testosterone (T) was significantly increased in the DiNP LOW group, however, the same DiNP concentration reduced the levels of 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P). The production of sperm was in general not affected, since spermiation index, sperm density, survival and the duration of forward motility did not exhibit any changes compared to controls. However, computer-assisted sperm analysis (CASA) showed that DiNP reduced the percentage of motile cells. The results clearly suggest a negative effect of DiNP via the diet on the male endocrine system of gilthead sea bream during the reproductive season.

Physiological responses of wheat planted in fluvo-aquic soils to di (2-ethylhexyl) and di-n-butyl phthalates

Di (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) are important pollutants that contaminate agricultural soils. We determined the effects of di (2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) on the production of reactive oxygen species, photosynthesis, and activity of antioxidant enzymes in wheat planted in fluvo-aquic soils. DBP- and DEHP-induced oxidative stress decreased the values of the photosynthetic/fluorescence parameters (except for intercellular carbon dioxide concentration) and chlorophyll content at the seedling, jointing, and booting stages. Moreover, the non-stomatal factor responsible for the net decrease in photosynthetic efficiency was identified as the decrease in fluorescence resulting from the decreased amount of chlorophyll a returning from the excited to the ground energy state. The content of superoxide anions and hydrogen peroxide in wheat leaves and roots increased with increasing DBP and DEHP supplementation, compared to the control. Antioxidant enzyme activities in the leaves and roots at the seedling stage increased at DBP and DEHP levels of 10 and 20 mg kg^-1, respectively, and the enzyme activities at the jointing and booting stages increased with increasing concentrations of the chemicals, compared to the control. These results demonstrated that increased levels of antioxidant enzymes play a significant role in protecting plant growth under DBP and DEHP stress.

Effects of DEHP on post-embryonic development, nuclear receptor expression, metabolite and ecdysteroid concentrations of the moth Spodoptera littoralis

Di (2-ethylhexyl) phthalate (DEHP) is recognized in vertebrates as an Endocrine Disrupting Chemical (EDC). DEHP can alter steroid hormones production, development, reproduction and behavior in vertebrates. Only few studies investigated DEHP effects on insects. However, some recent studies on aquatic insects showed that DEHP could also act as an EDC by interfering with the signaling pathways of ecdysteroids, the main hormones involved in the control of insect post-embryonic development and physiology. The aim of the study was to investigate (1) the fate of DEHP within a terrestrial insect species by exposing larvae to food containing a wide range of DEHP concentrations and (2) the effects of this chemical on their post-embryonic development and metamorphosis, by using a multi-level approach. DEHP was shown to be present both in larvae and resulting stages, with higher concentrations in chrysalises and adults than in larvae. DEHP concentrations also decreased at the end of the last larval instar, suggesting the metabolic transformation or excretion of this chemical during this time. Only the two highest DEHP doses induced higher insect mortality, whereas low and intermediate concentrations increased larval food consumption without affecting body weight. Metabolic profiles showed that in control insects, the last three days before metamorphosis correspond to a metabolic transition, but with time-dependent changes in treated insects. Interestingly, DEHP treatments also alter both hemolymphatic ecdysteroid titers and expression levels of ecdysteroid response genes. These results confirm that DEHP can alter insect post-embryonic development and metamorphosis, by interfering with ecdysteroid pathways.