Nonylphenol: Properties, legislation, toxicity and determination

Predictive modeling for the adsorptive and photocatalytic removal of phenolic contaminants from water using artificial neural networks

Numerous harmful phenolic contaminants are discharged into water that pose a serious threat to environment where two of the most important purification methodologies for the mitigation of phenolic contaminants are adsorption and photocatalysis. Besides cost, each process has drawbacks in terms of productivity, environmental impact, sludge creation, and the development of harmful by-products. To overcome these limitations, the modeling and optimization of water treatment methods is required. Artificial Intelligence (AI) is employed for the interpretation of treatment-based processes due to powerful learning, simplicity, high estimation accuracy, effectiveness, and improvement of process efficiency where artificial neural networks (ANNs) are most frequently employed for predicting and analyzing the efficiency of processes applied for the mitigation of these phenolic contaminants from water. ANNs are superior to conventional linear regression models because the latter are incapable of dealing with non-linear systems. ANNs can also reduce the operational cost of treating phenol-contaminated water. A correlation coefficient of >0.99 can be achieved using ANN with enhanced phenol mitigation percentage accuracy generally ranging from 80 % to 99.99 %. Using ANN optimization, the maximum phenol mitigation efficiencies achieved were 99.99 % for phenol, 99.93 % for bisphenol A, 99.6 % for nonylphenol, 97.1 % for 2-nitrophenol, 96.6 % for 4-chlorophenol and 90 % for 2,6-dichlorophenol. In numerous ANN models, Levenberg-Marquardt backpropagation algorithm for training was employed using MATLAB software. This study overviews their employment and application for optimization and modeling of removal processes and explicitly discusses the important input and output parameters necessary for better performance of the system. The comparison of ANNs with other AI techniques revealed that ANNs have better predictability for mitigation of most of the phenolic contaminants. Furthermore, several challenges and future prospects have also been discussed.

ERβ activation improves nonylphenol-induced depression and neurotransmitter secretion disruption via the TPH2/5-HT pathway

The aim of this study is to investigate the role of estrogen receptor β (ERβ) in nonylphenol (NP) - induced depression - like behavior in rats and its impact on the regulation of the TPH2/5-HT pathway. In the in vitro experiment, rat basophilic leukaemia cells (RBL-2H3) cells were divided into the four groups: blank group, NP group (20 μM), ERβ agonist group (0.01 μM), and NP＋ERβ agonist group (20 μM＋0.01 μM). For the in vivo experiment, 72 adult male Sprague-Dawley rats were randomly divided into following six groups: the Control, NP (40 mg/kg) group, ERβ agonist (2 mg/kg, Diarylpropionitrile (DPN)) group, ERβ inhibitor (0.1 mg/kg, 4-(2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl) phenol (PHTPP)) group, NP+ERβ agonist (40 mg/kg NP ＋ 2 mg/kg DPN) group, and NP+ERβ inhibitor (40 mg/kg NP + 0.1 mg/kg PHTPP) group, with 12 rats in each group. Each rat in drug group were given NP by gavage and/or received a single intraperitoneal injection of DPN 2 mg/kg or PHTPP 0.1 mg/kg. Both in vivo and in vitro, NP group showed a decrease in the expression levels of ERβ, tryptophan hydroxylase (TPH1), and tryptophan hydroxylase-2 (TPH2) genes and proteins, and reduced levels of DA, NE, and 5-hydroxytryptophan (5-HT) neurotransmitters. RBL-2H3 cells showed signs of cell shrinkage, with rounded cells, increased suspension and more loosely arranged cells. The effectiveness of the ERβ agonist stimulation exhibited an increase exceeding 60% in RBL-2H3 cells. The application of ERβ agonist resulted in an alleviation the aforementioned alterations. ERβ agonist activated the TPH2/5-HT signaling pathways. Compared to the control group, the NP content in the brain tissue of the NP group was significantly increased. The latency to eat for the rats was longer and the amount of food consumed was lower, and the rats had prolonged immobility time in the behavioral experiment of rats. The expression levels of ERβ, TPH1, TPH2, 5-HT and 5-HITT proteins were decreased in the NP group, suggesting NP-induced depression-like behaviours as well as disturbances in the secretion of serum hormones and monoamine neurotransmitters. In the NP group, the midline raphe nucleus showed an elongated nucleus with a dark purplish-blue colour, nuclear atrophy, displacement and pale cytoplasm. ERβ might ameliorate NP-induced depression-like behaviors, and secretion disorders of serum hormones and monoamine neurotransmitters via activating TPH2/5-HT signaling pathways.

Nonylphenol ethoxylate degradation in detergents during shelf time, a new exposure pathway, and a perspective on their substitution

Detergents are highly produced pollutants with environmental problems like foam generation and toxic effects in biota. Nonylphenol ethoxylates (NPEs) are efficient, economical, and versatile surfactants, used in detergents for more than 40 years due to their detergency capacity. In the environment, NPE biodegrades into the metabolite nonylphenol (NP), classified as an endocrine disruptor. The identification and quantification of 4-NP in a designed detergent and 30 commercially available detergents were performed to prove the degradation of NPE into 4-NP during storage time. This investigation introduces the first evidence of NPE degradation during storage in commercially available detergents, demonstrating a novel exposure pathway in humans that has not been explored before, representing potential human health risks. Therefore, simple, easy, low-cost, and available approaches to remove and substitute NP is paramount. Alkyl polyglucoside (APG) was assessed as a substitute, and the feasibility of this substitution was proven according to physical and chemical properties, cleaning performance, and antimicrobial properties. NPE substitution in detergents is demonstrated as a viable strategy to minimize exposure risks in humans and the environment.

Isomer-specific analysis of nonylphenol and their transformation products in environment: A review

Nonylphenols (NPs) are crucial fine chemicals widely employed in producing industrial and consumer surfactants that ultimately enter the environment through various pathways, leading to environmental pollution. NPs are suspected endocrine-disrupting chemicals that may accumulate in the body over time, resulting in unusual reproductive function. Due to limitations in analytical methods, NPs have typically been quantified as a whole in some studies. However, NPs are a mixture of multibranched structures, and different NP isomers exhibit distinct environmental behaviors and toxic effects. Therefore, it is critical to analyze environmental and human biological samples at the isomer-specific level to elucidate the contamination characteristics, human exposure load, and toxic effects of NPs. Accurately analyzing NP samples with various isomers, metabolites, and transformation products presents a significant challenge. This review summarizes recent advances in analytical research on NPs in technical products, environmental, and human biological samples, particularly emphasizing the synthesis and separation of standards and the transformation of NP homolog isomers in samples. Finally, the review highlights the research gaps and future research directions in this domain.

Molecularly imprinted polymers (MIPs) as efficient catalytic tools for the oxidative degradation of 4-nonylphenol and its by-products

Water pollution is a current global concern caused by emerging pollutants like nonylphenol (NP). This endocrine disruptor cannot be efficiently removed with traditional wastewater treatment plants (WTPs). Therefore, this work aimed to evaluate the adsorption influence of molecularly imprinted polymers (MIPs) on the oxidative degradation (ozone and ultraviolet irradiations) of 4-nonylphenol (4-NP) and its by-products as a coadjuvant in WTPs. MIPs were synthesized and characterized; the effect of the degradation rate under system operating conditions was studied by Box-Behnken response surface design of experiments. The variables evaluated were 4-NP concentration, ozone exposure time, pH, and MIP amount. Results show that the MIPs synthesized by co-precipitation and bulk polymerizations obtained the highest retention rates (> 90%). The maximum adsorption capacities for 4-NP were 201.1 mg L-1 and 500 mg L-1, respectively. The degradation percentages under O3 and UV conditions reached 98-100% at 120 s of exposure at different pHs. The degradation products of 4-NP were compounds with carboxylic and ketonic acids, and the MIP adsorption was between 50 and 60%. Our results present the first application of MIPs in oxidation processes for 4-NP, representing starting points for the use of highly selective materials to identify and remove emerging pollutants and their degradation by-products in environmental matrices.

Alkylphenols cause cytotoxicity and genotoxicity induced by oxidative stress in RTG-2 cell line

Alkylphenols ethoxylates are industrial surfactants, and the release in the environmental matrices produces degraded products, of which nonylphenol (NP) and octylphenol (OP) were the most common. They can be classified as endocrine disruptors since the estrogenic potential is widely recognized, but some others toxic aspects are in discussion. This study aimed to evaluate the toxicity of NP, OP, and mixtures of both through cellular, biochemical and genetic biomarkers in fish gonadal cell line RTG-2 exposed to nominal concentrations of 0.05; 0.5; 5; 50, and 100 μg mL^-1 of each chemical and their mixtures of 0.05, 0.5; 5 μg mL^-1 concentrations. After 24 h, the cells were collected for cytotoxic (neutral red - NR; crystal violet - CV, resazurin assay - RA and lactate-dehydrogenase - LDH), antioxidant system (glutathione-s-transferase - GST; superoxide-dismutase - SOD; glutathione-peroxidase - GPx and malondialdehyde - MDA) and genotoxic assays (alkaline comet assay and Fpg-modified alkaline comet assay). The chemicals and their mixtures were cytotoxic at 50 and 100 μg mL^-1, in general aspect, but LDH showed cytotoxicity since 0.05 μg mL^-1. The GST and SOD showed an activity increase trend in most tested groups, while GPx decreased at 5 μg mL^-1 of the mixture. The MDA increase in all groups resulted in lipid peroxidation. The reactive oxygen species caused DNA damage for all groups. The tested chemicals and concentrations have been found in the freshwater systems. They can induce cell toxicity in several parameters that could impair the gonadal tissues considering the RTG-2 responses.

Novel nonylphenol-degrading bacterial strains isolated from sewage sludge: Application in bioremediation of sludge

Nonylphenol (NP) is an anthropogenic pollutant frequently found in sewage sludge due to the insufficient degrading effectiveness of conventional WWTPs and has attracted attention as an endocrine disruptor. The aim of this study was to isolate specific NP-degrading bacteria from sewage sludge to be used in the degradation of this contaminant through bioaugmentation processes in aqueous solution and sewage sludge. Up to eight different bacterial strains were isolated, six of them not previously described as NP degraders. Bacillus safensis CN12 presented the best NP degradation in solution, and glucose used as an external carbon source increased its effect, reaching DT₅₀ degradation values (time to decline to half the initial concentration of the pollutant) of only 0.9 days and a complete degradation in <7 days. Four NP metabolites were identified throughout the biodegradation process, showing higher toxicity than the parent contaminant. In sewage sludge suspensions, the endogenous microbiota was capable of partially degrading NP, but a part remained adsorbed as bound residue. Bioaugmentation was used for the first time to remove NP from sewage sludge to obtain more environmentally friendly biosolids. However, B. safensis CN12 was not able to degrade NP due to its high adsorption on sludge, but the use of a cyclodextrin (HPBCD) as availability enhancer allowed us to extract NP and degrade it in solution. The addition of glucose as an external carbon source gave the best results since the metabolism of the sludge microbiota was activated, and HPBCD was able to remove NP from sewage sludge to the solution to be degraded by B. safensis CN12. These results indicate that B. safensis CN12 can be used to degrade NP in water and sewage sludge, but the method must be improved using consortia of B. safensis CN12 with other bacterial strains able to degrade the toxic metabolites produced.

4-[1-Ethyl-1-methylhexy]-phenol induces apoptosis and interrupts Ca2+ homeostasis via ROS pathway in Sertoli TM4 cells

Biological effect of an individual nonylphenol (NP) isomer extremely relies upon the side chain structure. This research was designed to evaluate the impact of NP isomer, 4-[1-ethyl-1-methylhexy]-phenol (NP₆₅), on Sertoli cells in vitro. Sertoli TM4 cells were exposed to various concentration (0, 0.1, 1, 10, or 20 μM) of NP₆₅ for 24 h, and the outcomes indicated that treatment of NP₆₅ induced reactive oxygen species (ROS) generation, oxidative stress, and apoptosis for Sertoli TM4 cells. In addition, it was found that NP₆₅ exposure affected homeostasis of Ca²⁺ in Sertoli TM4 cells by increasing cytoplasm [Ca²⁺]i, inhibiting Ca²⁺-ATPase activity and decreasing cyclic adenosine monophosphate (cAMP) concentration. Pretreatment with ROS scavenger, N-acetylcysteine (NAC), attenuated NP₆₅-induced oxidative stress as well as apoptosis for TM4 cells. Furthermore, NAC blocked NP₆₅-induced disorders of Ca²⁺ homeostasis by attenuating the growth of intracellular [Ca²⁺]i and the inhibition of Ca²⁺-ATPase and cAMP activities. Thus, we have demonstrated that NP₆₅ induced apoptosis as well as acted as a potent inhibitor of Ca²⁺-ATPase activity and resulted in disorder of Ca²⁺ homeostasis in Sertoli TM4 cells; ROS participated in the process. Our results supported the view that oxidative stress acted an essential role within the development of apoptosis and Ca²⁺ overload in TM4 cells as a consequence of NP₆₅ stimulation.

Reproductive Toxicity and Recovery Associated With 4-Non-ylphenol Exposure in Juvenile African Catfish (Clarias garepinus)

Although, the effects of 4-non-ylphenol (4-NP) on fish's reproductive hormones were assessed in several studies using adult models, however, the effect of this endocrine disruptor on immature fish's reproductive hormones was not addressed commonly. We aimed to study the apoptosis induction, hematotoxicity, reproductive toxicity, and the recovery associated with 4-NP exposure in juvenile African catfish [Clarias garepinus) using some hormones [17β-estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] and gonad histology as biomarkers. The toxic effects of 4-NP have been studied in many animal models, but there is still limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. A healthy juvenile C. gariepinus was categorized into four groups (n = 3/group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1, 0.2, and 0.3 mg/L for 15 days; they were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between the treatment groups and the control (P < 0.05), which were evident in E2 and T-values, whereas FSH, LH, total protein, and lipid peroxidation values showed non-significant differences among all groups at P < 0.05. Such a situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP treated in gonad tissues were recorded in juvenile C. gariepinus, reflecting their sensitivity to 4-NP estrogenic-like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-NP in juvenile C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in hematological parameters except for hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The parameters exhibiting significance decreased with such increased doses [red blood cells (RBCs), hematocrit (Hct), and white blood cells (WBCs)]. Similar patterns of significant variations toward the increase or decrease were recorded following the 15-day recovery period. Apoptotic frequency in erythrocytes and brain cells has increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

Ecotoxicological impacts caused by high demand surfactants in Latin America and a technological and innovative perspective for their substitution

Nowadays, water pollution represents a great concern due to population growth, industrialization, and urbanization. Every day hazardous chemical products for humans and aquatic organisms are disposed of arbitrarily from homes and industries. Even though detergents are considered an essential market, there is evidence of environmental impacts caused by surfactants like nonylphenol ethoxylate (NPE) and linear alkylbenzene sulfonates (LAS). Regulations about maximum allowable concentrations in sewage, surface water, and drinking water are scarce or null, mostly in developing countries like Latin American countries. Therefore, this review explores these two common toxic surfactants (NPE and LAS) and proposes a technological, innovative, and ecological perspective on detergents. Also, it establishes a starting point for industries to minimize adverse effects on humans and environmental health caused by these compounds.

Effects of 4-nonylphenol on adipogenesis in 3T3-L1 preadipocytes and C3H/10T1/2 mesenchymal stem cells

Obesogens are a subset of endocrine disruptor chemicals (EDCs) that cause obesity. The typical EDC 4-nonylphenol (4-NP) has been identified as an obesogen. However, the in vitro effects of 4-NP on adipogenesis remain unclear. In this study, 3T3-L1 preadipocytes and C3H/10T1/2 mesenchymal stem cells (MSCs) were used to investigate the influence of 4-NP on adipogenesis. The differentiation protocols for 3T3-L1 preadipocytes and C3H/10T1/2 MSCs took 8 and 12 days, respectively, beginning at Day 0. In differentiated 3T3-L1 preadipocytes, 20 μM 4-NP decreased cell viability on Days 4 and 8. Exposure to 4-NP inhibited triglyceride (TG) accumulation and adipogenic marker expression on Days 0-8, but the inhibitory effects were weaker on Days 2-8. The protein expression of pSTAT3 or STAT3 decreased on Days 0-8 and 2-8. Conversely, 4-NP promoted TG accumulation and the adipogenic marker expression in C3H/10T1/2 adipocytes. The opposing effects were attributed to physiological differences between the two cell lines. The 3T3-L1 preadipocytes are dependent on mitotic clonal expansion (MCE) to drive differentiation, while C3H/10T1/2MSCs and human preadipocytes are not. Additionally, 4-NP downregulated β-catenin expression in C3H/10T1/2 adipocytes. Accordingly, we hypothesized that 4-NP promotes adipogenesis. The role of the canonical Wnt pathway in the promotion of adipogenesis by 4-NP requires further validation. This study provides new insights into the mechanisms and appropriate risk management of 4-NP.

Pilot-scale evaluation of ozone as a polishing step for the removal of nonylphenol from tank truck cleaning wastewater

The presence of nonylphenol (NP) in the wastewater of the tank truck cleaning industry is a major concern because of its endocrine disruptive properties. In this paper, the use of ozone for degrading NP from tank truck cleaning wastewater was investigated by operating a pilot-scale biological wastewater treatment in combination with an ozonation unit. The impact of the added ozonation step on the removal of NP, soluble chemical oxygen demand (sCOD) and total organic carbon (TOC) was monitored over one year. sCOD and TOC removal were not significantly enhanced, but the NP peak concentrations in the effluent were significantly lower than those obtained after biological treatment only: a relatively low NP concentration was observed, even when peak loads were present in the influent of the pilot-scale biological wastewater treatment plant (influent_bio). Contrariwise, the effluent of the sole biological treatment follows the peak load trends of the influent_bio. During the ozonation period, the average NP concentration in the combined biological-ozone unit was 0.29 μg/L, compared to 1.89 μg/L for the effluent obtained after a sole biological treatment, resulting in an improved average removal efficiency of 32%.

Multigenerational reproduction and developmental toxicity, and HPG axis gene expression study on environmentally-relevant concentrations of nonylphenol in zebrafish

Nonylphenol (NP) is a toxic xenobiotic compound, which is persistent in the aquatic environment and is extremely toxic to aquatic organisms. Although the exact molecular mechanisms of its toxic effect are well understood, the multigenerational reproduction and multigenerational - gene expression changes caused by NP still remain unclear. The following work investigated the effect of NP on four consecutive generations of zebrafish by examining their growth and several reproductive parameters, the degree of gonad damage, and the expression of related reproduction related genes. The results showed that high concentrations (20 and 200 μg·L^-1) of NP could decrease growth and induce gonad damage in zebrafish. In addition, gnrh2 and gnrh3 genes were up-regulated, and fshβ and lhβ genes were downregulated in the hypothalamus in male zebrafish; while in female fish, the fshβ and lhβ were upregulated in P and F1 generations, and then down-regulated in the F2 generation. Meanwhile, the cyp19a1a gene was downregulated in the gonad of male fish, while the genes of fshr, lhr and esr showed a downward trend in females. Compared to P generation, F2 generation was more tolerant to higher NP concentrations (20 and 200 μg·L^-1), as was also more sensitive to lower concentrations of NP (2 μg·L^-1). Consequently, stress and damage caused by environmentally-relevant concentrations of aquatic pollutants in a vertebrate model were measured and predicted. Prevention and control measures can be actively and effectively proposed, which might be transversal to other exposed organisms, including humans. After several generations, typical transgenerational genetic phenomena might occur, which should be addressed by further studies.

Dose- and time-effects responses of Nonylphenol on oxidative stress in rat through the Keap1-Nrf2 signaling pathway

Nonylphenol (NP) is a representative environmental endocrine-disrupting compound that can induce oxidative stress in organisms. The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway acts an important role in preventing oxidative stress. The aim of this study was to investigate the influence of oxidative stress caused by NP on Keap1-Nrf2 pathway in rats. Rats were treated with NP (30, 90, 270 mg/kg) for different exposure time (7, 14 and 28 days). The levels of reactive oxygen species (ROS) in serum and glutathione S-transferase (GST), UDP-Glucuronosyl Transferase (UGT) in liver were detected by ELISA kits. Western blot was used to detect Keap1, Nrf2 protein expression in liver and cerebral cortex. The results showed that 28 days of NP exposure significantly increased ROS levels in NPH group. And 14 days exposure to NP significantly enhanced the levels of GST and UGT, while 28 days of exposure showed a suppressive effect. In liver, Keap1 levels was upregulated at 7, 14 and 28 days of NP exposure, while nuclear Nrf2 levels decreased at 7 and 28 days but increased at 14 days. In cerebral cortex, Keap1 and Nrf2 expression increased at 14 days but decreased at 28 days. Besides, with the prolongation of NP exposure time, the GST and UGT levels in NPM and NPH groups were increased firstly and then decreased, while Keap1 and Nrf2 protein levels were constantly decreased in liver and cerebral cortex. In conclusion, the lower dose and shorter exposure time of NP activated the Keap1-Nrf2 pathway that may reduce the damage of oxidative stress, but when further exposed to NP at higher dose and time, the pathway could be inhibited.

The development of isomer-specific analysis of branched 4-nonylphenol in food for dietary exposure - a critical review of analytical methods and occurrence in foodstuffs

4-Nonylphenol (4-NP) is a para-substituted phenolic compound comprising a straight or branched carbon chain group while branched 4-NP consists of 211 possible structural isomers. NP is recognised as an environmental pollutant and exists ubiquitously in both the environment and in food. 4-NP, especially branched 4-NP, has been shown to have the potential role of endocrine disruptor and xeno-oestrogen. Moreover, different NP isomers also exhibit different oestrogen-like activities. Recently, it was reported that the isomer-specific profile of 4-NP in foodstuffs varies greatly between and within food groups. Hence, risk assessment based on total branched 4-NP cannot reflect dietary risk. This study reviews the analytical methods applicable to conduct an isomer-specific analysis of 4-NP and its occurrence in foodstuffs. Lastly, research gaps are identified for future research.

Investigation of micropollutants removal from landfill leachate in a full-scale advanced treatment plant in Istanbul city, Turkey

Although the levels of micropollutants in landfill leachate and municipal wastewater are well-established, the individual removal mechanisms and the fate of micropollutants throughout a landfill leachate treatment plant (LTP) were seldom investigated. Therefore, the determination of the removal efficiencies and the fates of micropollutants in a full-scale leachate treatment plant located in the largest city of Turkey were aimed in this study. Some important processes, such as equalization pond, bioreactor, ultrafiltration (UF) and nanofiltration (NF), are being operated in the treatment plant. Landfill leachate was characterized as an intense pollution source of macro and micropollutants compared to other water types. Chemical oxygen demand (COD), NH₃, suspended solids (SS) and electrical conductivity (EC) values of the landfill leachate (and their removal efficiencies in the treatment plant) were determined as 18,656 ± 12,098 mg/L (98%), 3090 ± 845 mg/L (99%), 4175 ± 1832 mg/L (95%) and 31 ± 2 mS/cm (51%), respectively. Within the scope of the study, the most frequently and abundantly detected micropollutants in the treatment plant were found as heavy metals (8 ± 1.7 mg/L), VOCs (38 ± 2 μg/L), alkylphenols (9 ± 3 μg/L) and phthalates (8 ± 3 μg/L) and the overall removal efficiencies of these micropollutants ranged from -11% to 100% in the treatment processes. The main removal mechanism of VOCs in the aerobic treatment process has been found as the volatilization due to Henry constants greater than 100 Pa·m³/mol. However, the molecular weight cut off restriction of UF membrane has caused to less or negative removal efficiencies for some VOCs. The biological treatment unit which consists of sequential anoxic and oxic units (A/O) was found effective on the removal of PAHs (62%) and alkylphenols (87%). It was inferred that both NO₃ accumulation in anoxic reactor, high hydraulic retention time (HRT) and sludge retention time (SRT) in aerobic reactor provide higher biodegradation and volatilization efficiencies as compared to the literature. Membrane processes were more effective on the removal of alkylphenols (60-80%) and pesticides (59-74%) in terms of influent and effluent loads of each unit. Removal efficiencies for Cu, Ni and Cr, which were the dominant heavy metals, were determined as 92, 91 and 51%, respectively and the main removal mechanism for heavy metals has thought to be coprecipitation of suspended solids by microbial biopolymers in the bioreactor and the separation of colloids during membrane filtration. Total effluent loads of the LTP for VOCs, semi volatiles and heavy metals were 1.0 g/day, 5.2 g/day and 1.5 kg/day, respectively. It has been concluded that the LTP was effectively removing both conventional pollutants and micropollutants with the specific operation costs of 0.27 $/(kg of removed COD), 0.13 $/(g of removed VOCs), 0.35 $/(g of removed SVOCs) and 2.6 $/(kg of removed metals).

Emerging pollutants (EPs) in Latin América: A critical review of under-studied EPs, case of study -Nonylphenol

Emerging contaminants (EPs) represent a significant risk to human, ecological and environmental health. Although progress has been made in establishing monitoring in environmental matrices, health effects, legislation and control, there are still problems associated with regional bias and the types of EPs commonly assessed, which may underestimate the risk to health. In Latin America there are limited reports on environmental monitoring of EPs and it is generally focused on wastewater. This review identifies the current research deficiencies for emerging contaminants in the Latin American region, and we address the case of nonylphenol as an under-studied EP in the region. Nonylphenol is a degradation product of nonylphenol ethoxylate, which is a surfactant widely used in the manufacture of detergents in Latin America, environmental concentrations have been reported, predominantly in water, and the possible effects on species in this region have been also described. The importance of the review of this compound in the region lies in the fact that the Rotterdam Convention has catalogued nonylphenol as a severely restricted compound, so it is necessary to establish measures for its restriction and change to a sustainable technology. Finally, the example of NP presented in this review highlights the lack of regulation in Latin America regarding to EPs, resulting in the contamination of wastewater, effluents, rivers and drinking water. It is imperative to determine the potential effects, occurrence and concentration levels to improve the regulation of these pollutants in a timely manner.

Development and validation of an analytical method for detection and quantification of benzophenone, bisphenol A, diethyl phthalate and 4-nonylphenol by UPLC-MS/MS in surface water

Guandu River is the main water source for 9 million inhabitants in Rio de Janeiro city and some others included in the metropolitan region of the Rio de Janeiro State, Brazil. Here, the development of a chromatographic method and its application to assess the occurrence of 4-nonylphenol (4NP), benzophenone (BP), bisphenol A (BPA) and diethyl-phthalate (DEP), known as endocrine disruptors (EDs), is reported. Sample were prepared by solid phase extraction (SPE) with C18 cartridge and methanol as elution solvent. Validation of analytical method followed the United States Environmental Protection Agency protocol (USEPA 8000D guide) and selectivity, matrix effect, linearity, precision, accuracy, robustness, limit of detection (LOD) and limit of quantification (LOQ) were evaluated. The recovery was greater than 90%, accuracy was found between 80% and 115% and relative standard deviation (RSD) below 11.03%. LOQ ranged from 10.0 to 50.0 ng L−1, while the LOD ranged from 0.87 to 5.72 ng L−1. The coefficients of determination (R2) were greater than 0.99 for all compounds within a linear ranges of 10.0 to 500 ng L−1 for 4NP and BP and 50.0 to 500 ng L−1 for BPA and DEP. The method was therefore considered selective and robust for all micropollutants. Matrix effect was observed for BP, 4NP and DEP. The developed method was applied to analyze five samples collected monthly during 2018 at a selected sampling point of a river in Rio de Janeiro State. The maximum concentrations found for BPA, BP, DEP and 4NP were 182.04, 286.20, 2.56×103 and 13.48 ng L−1 respectively. These values are high enough to justify an investigation on the presence of these micropollutants in drinking water as well as to extend the monitoring for the search of similar pollutants and their metabolites.

Intergenerational toxicity of nonylphenol ethoxylate (NP-9) in Caenorhabditis elegans

The ethoxylated isomers of nonylphenol (NPEs, NP-9) are one of the main active ingredients present in nonionic surfactants employed as herbicides, cosmetics, paints, plastics, disinfectants and detergents. These chemicals and their metabolites are commonly found in environmental matrices. The aim of this work was to evaluate the intergenerational toxicity of NP-9 in Caenorhabditis elegans. The lethality, length, width, locomotion and lifespan were investigated in the larval stage L4 of the wild strain N2. Transgenic green fluorescent protein (GFP) strains were employed to estimate changes in relative gene expression. RT-qPCR was utilized to measure mRNA expression for neurotoxicity-related genes (unc-30, unc-25, dop-3, dat-1, mgl-1, and eat-4). Data were obtained from parent worms (P0) and the first generation (F1). Lethality of the nematode was concentration-dependent, with 48 h-LC₅₀ values of 3215 and 1983 μM in P0 and F1, respectively. Non-lethal concentrations of NP-9 reduced locomotion. Lifespan was also decreased by the xenobiotic, but the negative effect was greater in P0 than in F1. Non-monotonic concentration-response curves were observed for body length and width in both generations. The gene expression profile in P0 was different from that registered in F1, although the expression of sod-4, hsp-70, gpx-6 and mtl-2 increased with the surfactant concentration in both generations. None of the tested genes followed a classical concentration-neurotoxicity relationship. In P0, dopamine presented an inverted-U curve, while GABA and glutamate displayed a bimodal type. However, in F1, inverted U-shaped curves were revealed for these genes. In summary, NP-9 induced intergenerational responses in C. elegans through mechanisms involving ROS, and alterations of the GABA, glutamate, and dopamine pathways.

Nonylphenol induced individual and population fluctuation of Caenorhabditis elegans: Disturbances on developmental and reproductive system

The environmental risks that have arisen from endocrine disruption compounds (EDCs) have become global challenges, especially for persistent bio-accumulated xenobiotic chemicals, such as nonylphenol (NP). In the present study, the population dynamics of Caenorhabditis elegans (C. elegans) were systemically investigated by conducting developmental and reproductive bioassays under the exposure of NP, which has been widely detected in actual aquatic environments. The results revealed that under NP exposure (400 μg L^-1 NP), developmental indictors of C. elegans, including the body length and width were significantly inhibited at different life stages of L1 and L4 larva, and the growth curves were further adversely affected. In addition, abnormalities in reproductive systems were also observed under NP exposure. Such abnormalities obeyed a dose-dependent relationship with NP levels, which were closely related to the delayed spawning time and decreased reproductive rates. Moreover, the results from global genome expression analysis for nematodes revealed that the most significant enriched GO terms could be predominantly responsible for the dysregulation of growth and reproductive system. The population's parameters, including age composition and intrinsic growth rate (r_m d^-1), displayed significant changes, with a suppressed potentiality of population growth. Those data elucidated that NP exhibited a profound impact on the dynamic stability of the population, even with no obvious effect on certain biochemical markers.

Occurrence of selected endocrine disrupting compounds in the eastern cape province of South Africa

Endocrine-disrupting compounds are attracting attention worldwide because of their effects on living things in the environment. Ten endocrine disrupting compounds: 4-nonylphenol, 2,4-dichlorophenol, estrone, 17β-estradiol, bisphenol A, 4-tert-octylphenol, triclosan, atrazine, imidazole and 1,2,4-triazole were investigated in four rivers and wastewater treatment plants in this study. Rivers were sampled at upstream, midstream and downstream reaches, while the influent and effluent samples of wastewater were collected from treatment plants near the receiving rivers. Sample waters were freeze-dried followed by extraction of the organic content and purification by solid-phase extraction. Concentrations of the compounds in the samples were determined with ultra-high performance liquid chromatography-tandem mass spectrometry. The instrument was operated in the positive electrospray ionization (ESI) mode. The results showed that these compounds are present in the samples with nonylphenol > dichlorophenol > bisphenol A > triclosan > octylphenol > imidazole > atrazine > triazole > estrone > estradiol. Nonylphenol has its highest concentration of 6.72 μg/L in King Williams Town wastewater influent and 2.55 μg/L in midstream Bloukrans River. Dichlorophenol has its highest concentration in Alice wastewater influent with 2.20 μg/L, while it was 0.737 μg/L in midstream Bloukrans River. Uitenhage wastewater effluent has bisphenol A concentration of 1.684 μg/L while it was 0.477 μg/L in the downstream samples of the Bloukrans River. Generally, the upstream samples of the rivers had lesser concentrations of the compounds. The wastewater treatment plants were not able to achieve total removal of the compounds in the wastewater while runoffs and wastes dump from the cities contributed to the concentrations of the compounds in the rivers.

Mixture toxicity of chlorpyrifos-methyl, pirimiphos-methyl, and nonylphenol in Atlantic salmon (Salmo salar) hepatocytes

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Shotgun lipidomics points to combined effects on 18:0 and 18:1 lipid species.

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Combined effects seen on membrane phospholipids and TAG in salmon hepatocytes.

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Inhibited stearoyl CoA desaturase (SCD) and increased Δ6 desaturase (D6D) activity.

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Adjuvants may amend toxicity of active ingredient in pesticide formulations.

Pesticide formulations typically contain adjuvants added to enhance the performance of the active ingredient. Adjuvants may modify the bioavailability and toxicity of pesticides. In this study, the aim was to examine to which degree nonylphenol (NP) may interfere with the toxicity of two organophosphorus pesticides found in aquafeeds, chlorpyrifos-methyl (CPM) and pirimiphos-methyl (PPM). Atlantic salmon liver cells were exposed to these compounds singly or in combinations for 48 h using 3D cell cultures. Cytotoxicity, gene expression (RT-qPCR), and lipidomics endpoints were used to assess toxicity. The dose-response assessment showed that NP was the most toxic compound at equimolar concentrations (100 μM). Shotgun lipidomics pointed to a general pattern of elevated levels of saturated 18:0 fatty acids and declined levels of 18:1 monounsaturated fatty acids by the combined treatment. All three compounds had a distinct effect on membrane phospholipids, in particular on phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Lipid species patterns predicted inhibited stearoyl CoA desaturase (SCD) activity and increased Δ6 desaturase (D6D) activity in co-treated cells. While all three compounds alone mitigated increased triacylglycerol (TAG) accumulation, combined treatment resulted in lower total TAG in the cells. Multivariate analysis with PLS regression showed significant combined effects for nine genes (d5d, d6d, scd, srebf2, vtg, esr1, cyp1, ugt1a, and cat) and four lipid species (FFA 22:5, LPC 18:0, TAG52:1-FA16:0, and TAG52:1-FA18:0). In summary, this study demonstrates that the adjuvant can be the main contributor to the toxicity of a mixture of two organophosphorus pesticides with relatively low toxicity in fish cells.

Occurrence and Risk Assessment of Steroidal Hormones and Phenolic Endocrine Disrupting Compounds in Surface Water in Cuautla River, Mexico

In this study, two hormones 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), and three phenolic compounds, bisphenol A (BPA), 4-N-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP), were determined in surface water in the Cuautla River at the State of Morelos during the dry-season in Mexico. The endocrine disrupting compounds (EDCs) were extracted from water samples using solid-phase extraction (SPE) with end-capped C18, and then the extracts were chemically derivatized to TMS (trimethylsylane)-compounds and analyzed by gas chromatography coupled to mass spectrometry (GCMS). The most abundant compound was BPA (22.46 ± 30.17 ng L−1), followed by 4-t-OP (11.24 ± 11.76 ng L−1), 4-NP (7.53 ± 14.88 ng L−1), EE2 (2.37 ± 4.36 ng L−1) and E2 (0.97 ± 1.82 ng L−1). The residual amounts of target compounds could either reach stream surface water from direct domestic wastewater discharges, conventional wastewater treatment plant or can be a result from the use of agrochemicals in crop areas. The EDCs in Cuautla River exerted a high pressure on the aquatic ecosystem because their presences in surface water caused medium and high potential ecological risk. Besides, it was found that aquatic organisms were exposed to estrogenic activity.

Occurrence, fate and toxic effects of the industrial endocrine disrupter, nonylphenol, on plants - A review

Nonylphenol (NP) and its detrimental effects on the environment, humans, wildlife, fish and birds is an increasingly important global research focus. The number of investigations on the toxicity and metabolic fate of NP in plants is however limited. This paper reviews the prevalence and source of NP in plants and the effect it has on its morphological, physiological and ultrastructural status. Fruit and vegetables have been found to contain levels of NP that is twenty-fold exceeding the no observable effect level (NOEL) of freshwater algae. Apart from the potential risk this poses to the health of consumers, it can overburden the plant's natural defence system, leading to growth disorders. Plants exposed to NP show signs of overall growth reduction, changes in organelle structure and oxidative damage. These adverse effects may exacerbate the food security dilemma faced by many countries and impede their progress towards attaining the sustainable development goals.

Gonadal, body color, and genotoxic alterations in Lithobates catesbeianus tadpoles exposed to nonylphenol

Endocrine disrupting chemicals are one of the most important factors contributing to worldwide amphibian decline. The 4-nonylphenol (NP) is a degradation product of several compounds, such as detergents and pesticides, affecting the aquatic environment. Here, we test whether treatment with NP has an effect on developing ovarian tissue, nuclear abnormalities in erythrocytes, and body darkness in pre-metamorphic tadpoles of the bullfrog Lithobates catesbeianus. Tadpoles were exposed for 14 days to three different concentrations of NP (1, 10, and 100 μg/L) besides the control group, which was maintained only with water. After determining body coloration, animals were euthanized and gonads and blood were collected and processed for histology and genotoxic analysis. Even though most animals were females, intersex tadpoles were observed in control and treated groups and there were no males in any group. The highest concentration of NP showed an increase in atretic oocytes, but the area corresponding to somatic compartment and early and late germ cells were not affected. Furthermore, all treated groups presented higher amount of nuclear abnormalities in erythrocytes and body darkening when compared with the control group. These results suggest that NP causes genetic damage and morphological alterations in L. catesbeianus tadpoles by disrupting oogenesis, inducing genotoxicity and increasing body coloration. Its effects on gonadal development could cause future impairments in reproduction, while its deleterious effects on genotoxicity and body pigmentation could be used as a biomarker of effect to this compound.