Toxicity of methylparaben to green microalgae species and derivation of a predicted no effect concentration (PNEC) in freshwater ecosystems

Effects of the Pesticide Carbofuran on Two Species of Chlorophyceae (Desmodesmus communis and Pseudopediastrum boryanum) and Their Pesticide Bioremediation Ability

Carbofuran is one of the most toxic broad-spectrum pesticides. We evaluated the effects of carbofuran on two species of microalgae, Pseudopediastrum boryanum and Desmodesmus communis, through measurements of cell viability, biomass, chlorophyll content, and the production of reactive oxygen species (ROS). The ability of these algae to remove carbofuran dissolved in the media was also determined. For the evaluations, both microalgae species were exposed to carbofuran (FURADAN 350 SC®) at concentrations of 100, 1000, and 10,000 µg L-1 for 7 days. Algae cell viability and chlorophyll-a concentration were not affected by the presence of carbofuran. Both species grew when exposed to the pesticide; however, the microalgae D. communis grew less than its respective control when exposed to the highest concentration (10,000 µg L-1 of carbofuran), indicating an adverse effect of the pesticide on this species. A significant increase in ROS production was observed in D. communis and P. boryanum when exposed to the highest concentration tested. The microalgae P. boryanum completely removed carbofuran in the media within 2 days, regardless of the concentration, whereas D. communis achieved the same result only after 5 days of exposure. Growth inhibition was observed only until the disappearance of carbofuran from the media. The present study suggests the use of microalgae, mainly P. boryanum, as potential tools for the remediation of environments contaminated by carbofuran because of their resistance to the insecticide and their ability to remove it rapidly from water. Environ Toxicol Chem 2024;00:1-12. © 2023 SETAC.

Toxicity of benzyl paraben on aquatic as well as terrestrial life

Parabens are derivatives of alkyl esters of p-hydroxybenzoic acid and come in different classes. These compounds are primarily used as antimicrobial preservative agents in many commercial products, including cosmetics and pharmaceuticals. Accordingly, Benzyl paraben (BeP) is known to be a potential endocrine disruptor. The aim of this study was to determine the toxicity of benzyl paraben (BeP) on aquatic and terrestrial organisms, specifically Scenedesmus sp., Moina macrocopa, and Eisenia fetida. All the organisms were treated with different concentrations of BeP (0.025 mg/L and 1000 mg/L), and LC25, LC50, and LC90 values were used to measure the toxicity levels. Results showed the LC values of BeP for M. macrocopa (3.3 mg/L, 4.7 mg/L, 7.3 mg/L) and E. fetida (173.2 mg/L, 479.8 mg/L, 1062 mg/L), respectively. Toxicity tests on green algae (Scenedesmus sp.) were conducted, the green algae were subjected to various BeP concentration. At 50 mg/L of BeP, cell viability was reduced to 56.2% and the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay indicated 35.4% viable cells. The chlorophyll value and the biochemical parameters of the algal cells were corroborative with the cell viability test. Lethal indices (LC50) for M. macrocopa and E. fetida were evaluated for their toxicity on biochemical properties and were found to be catalase (0.111 mg/L, 0.5 mg/L), lipid peroxidation (0.072 mg/L, 0.056 mg/L), and total protein (0.309 mg/L, 0.314 mg/L), respectively. Overall, this study demonstrated the toxic impact of BeP on non-target aquatic as well as terrestrial species.

Different isoforms of parabens into marine environment: Biological effects on the bacterium Aliivibrio fischeri and the marine mussel Mytilus galloprovincialis

Different isoforms of alkyl esters of p-Hydroxybenzoic acid, also known as parabens, are of great concern due to their widespread presence into the aquatic environment, their high concentrations in wastewater discharges, as well as their ability to induce adverse effects on aquatic organisms. Considering the imperative need for assessing their fate and risk to aquatic environment, the present study investigated the biological effects of two isoforms of parabens, methyl- (MeP) and propyl- (PrP), on the bacterium Aliivibrio fischeri (using the Bioluminescence Inhibition/Microtox® bioassay) and the mussel Mytilus galloprovincialis (in terms of mussel mortality, cellular, oxidative and genotoxic stress indices). The assessment of MeP and PrP behavior into aquatic media (artificial sea water/ASW and 2 % NaCl), primarily performed by UHPLC-UV-MS analysis, showed only a slight hydrolysis of PrP to 4-Hydrobenzoic acid (4-HBA). Furthermore, exposure of both species to different concentrations of each paraben revealed differences among their toxic potential, as well as their ability to cause cellular, oxidative and genotoxic effects on hemocytes of challenged mussels. Interestingly, the Microtox® bioassay showed that PrP mediated toxicity in A. fischeri were more pronounced than MeP, as revealed by the estimated toxic endpoints (in terms of concentration that promote 50 % of bioluminescence inhibition, EC50). Similarly, in challenged mussels, a significant disturbance of mussel hemocytes' lysosomal membrane integrity, as well as enhanced levels of superoxides, nitric oxides, lipid peroxidation byproducts, and micronuclei formation were observed. These findings are of great interest, since MeP and PrP differential toxic potential, as well their ability to induce pre-pathological alterations in marine species, like mussels, give new evidence for their risk to aquatic biota.

Methylparaben toxicity and its removal by microalgae Chlorella vulgaris and Phaeodactylum tricornutum

The widespread occurrence of methylparaben (MPB) has aroused great concern due to its weak estrogenic endocrine-disrupting property and potential toxic effects. However, the degradation potential and pathway of MPB by microalgae have rarely been reported. Here, microalgae Chlorella vulgaris and Phaeodactylum tricornutum were used to investigate their responses, degradation potential and mechanisms towards MPB. MPB showed low-dose stimulation (by 86.02 ± 0.07% at 1 mg/L) and high-dose inhibition (by 60.17 ± 0.05% at 80 mg/L) towards the growth of C. vulgaris, while showed inhibition for P. tricornutum (by 6.99 ± 0.05%-20.14 ± 0.19%). The degradation efficiencies and rates of MPB were higher in C. vulgaris (100%, 1.66 ± 0.54-5.60 ± 0.86 day^-1) than in P. tricornutum (4.3-34.2%, 0.04 ± 0.01-0.08 ± 0.00 day^-1), which could be explained by the significantly higher extracellular enzyme activity and more fluctuation of the protein ratio for C. vulgaris, indicating a higher ability of C. vulgaris to adapt to pollutant stress. Biodegradation was the main removal mechanism of MPB for both the two microalgae. Furthermore, two different degradation pathways of MPB by the two microalgae were proposed. MPB could be mineralized and completely detoxified by C. vulgaris. Overall, this study provides novel insights into MPB degradation by microalgae and strategies for simultaneous biodegradation and detoxification of MPB in the environment.

Disparate toxicity mechanisms of parabens with different alkyl chain length in freshwater biofilms: Ecological hazards associated with antibiotic resistome

As emerging organic pollutants, parabens are of global concern because of their ubiquitous presence and adverse effects. However, few researchers have addressed the relationship between parabens' structural features and toxicity mechanisms. This study conducted theoretical calculations and laboratory exposure experiments to uncover the toxic effects and mechanisms of parabens with different alkyl chains in freshwater biofilms. The result demonstrated that parabens' hydrophobicity and lethality increased with their alkyl-chain length, whereas the possibility of chemical reactions and reactive sites were unchanged despite the alkyl-chain length alteration. Due to the hydrophobicity variation, parabens with different alkyl-chain presented different distribution patterns in cells of freshwater biofilms and consequently induced distinct toxic effects and led to diverse cell death modes. The butylparaben with longer alkyl-chain preferred to stay in the membrane and altered membrane permeability by non-covalent interaction with phospholipid, which caused cell necrosis. The methylparaben with shorter alkyl-chain preferred to enter into the cytoplasm and influence mazE gene expression by chemically reacting with biomacromolecules, thereby triggering apoptosis. The different cell death patterns induced by parabens contributed to different ecological hazards associated with antibiotic resistome. Compared with butylparaben, methylparaben was more likely to spread ARGs among microbial communities despite its lower lethality.

Butylparaben disordered intestinal homeostasis in Chinese striped-necked turtles (Mauremys sinensis)

Butylparaben (BuP) is regarded as a widespread pollutant, which has potential risk to aquatic organisms. Turtle species are an important part of aquatic ecosystems, however, the effect of BuP on aquatic turtles is not known. In this study, we evaluated the effect of BuP on intestinal homeostasis of Chinese striped-necked turtle (Mauremys sinensis). We exposed turtles to concentrations of BuP (0, 5, 50, and 500 μg/L) for 20 weeks, then investigated the composition of gut microbiota, the structure of intestine, and the inflammatory and immune status. We found BuP exposure significantly changed the composition of gut microbiota. Specially, the unique genus in three concentrations of BuP-treated groups mainly was Edwardsiella, which was not present in control group (0 μg/L of BuP). In addition, the height of intestinal villus was shortened, and the thickness of muscularis was thinned in BuP-exposed groups. Particularly, the number of goblet cells obviously decreased, the transcription of mucin2 and zonulae occluden-1 (ZO-1) significantly downregulated in BuP-exposed turtles. Meanwhile, neutrophils and natural killer cells in lamina propria of intestinal mucosa increased in BuP-treated groups, especially in high concentration of BuP (500 μg/L). Moreover, the mRNA expression of pro-inflammatory cytokines, especially IL-1β showed a significant upregulation with BuP concentrations. Correlation analysis indicated the abundance of Edwardsiella was positively correlated with IL-1β and IFN-γ expression, whereas its abundance was negatively correlative with the number of goblet cells. Taken together, the present study demonstrated BuP exposure disordered intestinal homeostasis through inducing dysbiosis of gut microbiota, causing inflammatory response and impairing gut physical barrier in turtles, which emphasized the hazard of BuP to health of aquatic organism.

Novel method in emerging environmental contaminants detection: Fiber optic sensors based on microfluidic chips

Recently, human industrial practices and certain activities have caused the widespread spread of emerging contaminants throughout the environmental matrix, even in trace amounts, which constitute a serious threat to human health and environmental ecology, and have therefore attracted the attention of research scholars. Different traditional techniques are used to monitor water pollutants, However, they still have some disadvantages such as high costs, ecological problems and treatment times, and require technicians and researchers to operate them effectively. There is therefore an urgent need to develop simple, inexpensive and highly sensitive methods to sense and detect these toxic environmental contaminants. Optical fiber microfluidic coupled sensors offer different advantages over other detection technologies, allowing manipulation of light through controlled microfluidics, precise detection results and good stability, and have therefore become a logical device for screening and identifying environmental contaminants. This paper reviews the application of fiber optic microfluidic sensors in emerging environmental contaminant detection, focusing on the characteristics of different emerging contaminant types, different types of fiber optic microfluidic sensors, methodological principles of detection, and specific emerging contaminant detection applications. The optical detection methods in fiber optic microfluidic chips and their respective advantages and disadvantages are analyzed in the discussion. The applications of fiber optic biochemical sensors in microfluidic chips, especially for the detection of emerging contaminants in the aqueous environment, such as personal care products, endocrine disruptors, and perfluorinated compounds, are reviewed. Finally, the prospects of fiber optic microfluidic coupled sensors in environmental detection and related fields are foreseen.

Assessing the potential for nevirapine removal and its ecotoxicological effects on Coelastrella tenuitheca and Tetradesmus obliquus in aqueous environment

Remediation of the antiretroviral (ARV) drug, nevirapine (NVP) has attracted considerable scientific attention in recent years due to its frequent detection and persistence in aquatic environments and potential hazards to living organisms. Algae-based technologies have been emerging as an environmentally friendly option for the removal of pharmaceutical compounds, but their ARV drug removal potential has not been fully explored yet. This study aimed to explore the ecotoxicity and removal potential of NVP by two microalgal species, Coelastrella tenuitheca and Tetradesmus obliquus. Lower environmental concentrations (up to 200 ng L^-1) of NVP enhanced the microalgal growth, and the highest dry cell weight of 941.27 mg L^-1 was obtained in T. obliquus at 50 ng L^-1 NVP concentration. Both microalgae showed varying removal efficiencies (19.53-74.56%) when exposed to NVP concentration levels of up to 4000 ng L^-1. At the late log phase (day 8), T. obliquus removed the highest percentage of NVP (74.56%), while C. tenuitheca removed 48% at an initial NVP concentration of 50 ng L^-1. Photosynthetic efficiency (Fv/Fm and rETR) of the two microalgal species, however, was not affected by environmental concentrations of NVP (up to 4000 ng L^-1) at the mid log phase of growth. SEM analysis demonstrated that both algal species produced distinct ridges on their cell surfaces after NVP uptake. In the ecotoxicity study, the calculated IC₅₀ values of NVP (0-100 mg L^-1) after 96 h of exposure were 23.45 mg L^-1 (C. tenuitheca) and 18.20 mg L^-1 (T. obliquus). The findings of the present study may contribute to a better understanding of the environmental hazards associated with NVP and the efficacy of microalgae in removing this pharmaceutical from aquatic environments.

The distinct resistance mechanisms of cyanobacteria and green algae to sulfamethoxazole and its implications for environmental risk assessment

Cyanobacteria and green algae are the OECD recommended test organisms for environmental toxicity assessments of chemicals. Whether the differences in these two species' responses to the identical chemical affect the assessment outcomes is a question worth investigating. Firstly, we investigated the distinct resistance mechanisms of Synechococcus sp. (cyanobacteria) and R. subcapitata (green algae) to sulfamethoxazole (SMX). The antioxidant system analysis demonstrated that R. subcapitata mainly relies on enhancing the activity of first line defense antioxidants, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), which is the most powerful and efficient response to get rid of ROS, whereas Synechococcus sp. depends upon increasing the activity of glutathione-S-transferase (GST) and GPx to resist oxidative stress. Besides, a total 7 transformation products (TPs) of SMX were identified in R. subcapitata culture medium. The analysis of conjectural transformation pathways and the predicted toxicity indicates that R. subcapitata could relieve SMX toxicity by degrading it to low eco-toxic TPs. Additionally, we summarized numerous exposure data and assessed the environmental risk of various antibiotics, revealing an inconsistent result for the same type of antibiotic by using cyanobacteria and green algae, which is most likely due to the different resistance mechanisms. In the future, modified indicators or comprehensive assessment methods should be considered to improve the rationality of environmental toxicity assessments.

Cosmetic Preservatives: Hazardous Micropollutants in Need of Greater Attention?

In recent years, personal care products (PCPs) have surfaced as a novel class of pollutants due to their release into wastewater treatment plants (WWTPs) and receiving environments by sewage effluent and biosolid-augmentation soil, which poses potential risks to non-target organisms. Among PCPs, there are preservatives that are added to cosmetics for protection against microbial spoilage. This paper presents a review of the occurrence in different environmental matrices, toxicological effects, and mechanisms of microbial degradation of four selected preservatives (triclocarban, chloroxylenol, methylisothiazolinone, and benzalkonium chloride). Due to the insufficient removal from WWTPs, cosmetic preservatives have been widely detected in aquatic environments and sewage sludge at concentrations mainly below tens of µg L^-1. These compounds are toxic to aquatic organisms, such as fish, algae, daphnids, and rotifers, as well as terrestrial organisms. A summary of the mechanisms of preservative biodegradation by micro-organisms and analysis of emerging intermediates is also provided. Formed metabolites are often characterized by lower toxicity compared to the parent compounds. Further studies are needed for an evaluation of environmental concentrations of preservatives in diverse matrices and toxicity to more species of aquatic and terrestrial organisms, and for an understanding of the mechanisms of microbial degradation. The research should focus on chloroxylenol and methylisothiazolinone because these compounds are the least understood.

Probabilistic Risk Assessment of Polycyclic Aromatic Hydrocarbons in a Colombian Reservoir

The purpose of this research was to evaluate the concentrations, sources and ecological risk assessment of sixteen polycyclic aromatic hydrocarbons (PAHs) present in water from the La Fe reservoir, Colombia in the months of October and November of 2017 and 2018. Concentrations of PAHs in water were measured with semipermeable membrane devices (SPMD) which allow obtaining the dissolved concentrations of the PAHs in the reservoir, emphasizing the reactivity and bioavailability in the environment. The PAHs analyses were carried out by means of gas chromatography, coupled with tandem mass spectrometry (GC/MS-MS) with triple quadrupole (QqQ). The environmental risk assessment using the estimation of risk quotient with deterministic and probabilistic method, the predictive no-effect concentration (PNEC) and environmental exposure concentration (EEC) in water indicate a negligibe risk for probabilistic method for all PAHs evaluated (RQ < 0.1).

Differential Effects of Atrazine on Chlorophyceae Species and Association with Morphology, Photosynthesis, Chlorophyll Content, and Glutathione-S-Transferase Activity

Atrazine is a herbicide widely used in the control of weeds in crops such as corn, sugar cane, and sorghum. It is often found in aquatic environments, where it can potentially endanger nontarget organisms such as microalgae. The present study evaluated atrazine toxicity to seven different species of Chlorophyceae and the tolerance of the species to the herbicide was related to morphological, photosynthetic, chlorophyll-a content and the activity of the glutathione-S-transferase enzyme (GST). The comparison of median effect concentration (EC50) values for growth inhibition indicates higher toxicity of atrazine for Pseudopediastrum boryanum and Desmodesmus communis, intermediate toxicity for Ankistrodesmus densus, Chlamydomonas puliminiorfes, and Raphidocelis subcapitata, and lower toxicity for Kirchneriella lunaris and Ankistrodesmus falcatus (EC50: 38, 42, 66, 103, 248, 1004, and 1585 µg L^-1 atrazine, respectively). Principal component analysis (PCA) with algal characteristics suggested that the atrazine-sensitive algae P. boryanum and D. communis were positively associated with photosynthetic levels and negatively associated with GST activity and chlorophyll-a concentration. The PCA also suggested that the atrazine-tolerant algae A. falcatus and K. lunaris were positively associated with morphological parameters, where the larger the cell size, the more tolerant. Although it is difficult to associate a single characteristic of algae as the key factor determining the tolerance to atrazine, results presented in this work indicate that the cell area, the photosynthetic parameters (mainly saturating irradiance), chlorophyll-a content, and the biotransformation by GST in combination may be potential predictors for the differential tolerance of Chlorophyceae species to the herbicide. Environ Toxicol Chem 2022;41:1675-1685. © 2022 SETAC.

Ecotoxicological Consequences of the Abatement of Contaminants of Emerging Concern by Ozonation—Does Mixture Complexity Matter?

Ozonation has been used to degrade persistent water contaminants, namely, pharmaceuticals and personal care products (PPCPs). However, ozonation can lead to by-products that can be more toxic than the parent compounds. This work aims to assess whether the ecotoxicological effects of ozonation are modified as the initial matrix being treated increases in complexity, considering mixtures of 2, 3, 4 and 5 PPCPs. The following PPCPs were used: two parabens (metylparaben (MP) and propylparaben (PP)), paracetamol (PCT), sulfamethoxazole (SMX) and carbamazepine (CBZ). The following model species were used to assess toxicity: the crustacean Daphnia magna, the microalgae Raphidocelis subcapitata, the macrophyte Lemna minor and the watercress Lepidium sativum. There was a trend of increased toxicity with increasing mixture complexity of the untreated samples, except for D. magna. The same was observed after ozonation with the exception of the mixture MP+PP, which showed high toxicity to all the tested species, namely 100% immobilization of D. magna. The toxicity of SMX to the primary producers decreased pronouncedly after ozonation, except for L. minor. This study highlights the importance of considering the complexity of the matrix being treated and of using an ecotoxicological test battery with a wide diversity of species for assessing ozonation efficiency.

Emerging contaminants of high concern for the environment: Current trends and future research

Wastewater is contaminated water that must be treated before it may be transferred into other rivers and lakes in order to prevent further groundwater pollution. Over the last decade, research has been conducted on a wide variety of contaminants, but the emerging contaminants are those caused primarily by micropollutants, endocrine disruptors (EDs), pesticides, pharmaceuticals, hormones, and toxins, as well as industrially-related synthetic dyes and dye-containing hazardous pollutants. Most emerging pollutants did not have established guidelines, but even at low concentrations they could have harmful effects on humans and aquatic organisms. In order to combat the above ecological threats, huge efforts have been done with a view to boosting the effectiveness of remediation procedures or developing new techniques for the detection, quantification and efficiency of the samples. The increase of interest in biotechnology and environmental engineering gives an opportunity for the development of more innovative ways to water treatment remediation. The purpose of this article is to provide an overview of emerging sources of contaminants, detection technologies, and treatment strategies. The goal of this review is to evaluate adsorption as a method for treating emerging pollutants, as well as sophisticated and cost-effective approaches for treating emerging contaminants.

Environmental risk assessment of parabens in surface water from a Brazilian river: the case of Mogi Guaçu Basin, São Paulo State, under precipitation anomalies

Parabens are preservatives widely used by industry since these compounds have antifungal properties, relative low cost, and stability over a wide pH range. This study aims to quantify and assess the environmental risks of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in surface water from a Brazilian River, Mogi Guaçu. The State of São Paulo, including the Mogi Guaçu River region, suffered from a period of intense drought and high temperatures, which caused anomalies in river flows and water supply problems. The water samples were collected from 14 locations, along 300 km of river extension, at four different seasons. Samples were previously extracted and pre-concentrated by dispersive liquid-liquid microextraction (DLLME) and later analyzed by ultra-performance liquid chromatography coupled with electrospray ionization in tandem with mass spectrometry (UPLC-ESI-MS/MS) detector. During the sampling period, PP was detected in 89.3% of the water samples, MP in 87.5%, EP in 73.2%, and BP in 48.2%. The sum of parabens' average levels was 42.2 μg L^-1 in Winter, 41.5 μg L^-1 in Summer, 36.6 μg L^-1 in Autumn, and 31.5 μg L^-1 in Spring. These levels can be attributed to the smaller dilution effect caused by the drought period. Also, ecological risk assessment indicated that parabens could take a low, medium, and high risk for target organisms in the measured aquatic environments, especially considering Pimephales promelas where 15% of the samples do not present potential risk, 84% of samples can present medium risk and only 1% have low risk. Besides, the risks for BP are also considerably higher, when almost 40% presents for high risks and 60% for medium risks. The present study indicates worrisome threats to the water source and to allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect.

A new insight into the ARG association with antibiotics and non-antibiotic agents-antibiotic resistance and toxicity

Although concerns have been raised about co-selection for antibiotic resistance and various antibiotics and non-antibiotic agents, the data on their association in urban sludge is still limited. In addition, antibiotic contamination can result in not only the toxicity but also the antibiotic resistance. In this study, the first large-scale identification of antibiotics and non-antibiotic agents concern for co-selection of resistance against antibiotics was conducted in urban sludge. Co-occurrence analysis showed that antibiotic resistance genes (ARGs) had no significant correlation with the corresponding antibiotics. Therefore, the results of co-occurrence analysis based on antibiotic concentration and ARG abundance were always ambiguous and difficult to interpret. However, antibiotic resistance was positively correlated with highly toxic compounds such as diclofenac, enrofloxacin and nicotine, suggesting that environmental contaminants might influence antibiotic resistance while exerting toxicity through mechanisms such as changes in microbial community and enzyme activity. The close correlation between class 1 integrase gene (intI1) and diclofenac/enrofloxacin indicated that the co-selection scenario between environmental contaminants and ARGs was likely mediated via intI1. In total, the derived co-occurrence patterns improve our understanding of the co-selection between ARGs, antibiotics and non-antibiotic agents, and also reaffirm the importance of potential role of non-antibiotic agents in the global spread of antibiotic resistance.

Toxicity and removal of parabens from water: A critical review

Parabens are biocides used as preservatives in food, cosmetics and pharmaceuticals. They possess antibacterial and antifungal activity due to their ability to disrupt cell membrane and intracellular proteins, and cause changes in enzymatic activity of microbial cells. Water, one of our most valuable natural resource, has become a huge reservoir for parabens. Halogenated parabens from chlorination/ozonation of water contaminated with parabens have shown to be even more persistent in water than other types of parabens. Unfortunately, there is dearth of data on their (halogenated parabens) presence and fate in groundwater which serves as a major source of drinking water for a huge population in developing countries. An attempt to neglect the presence of parabens in water will expose man to it through ingestion of contaminated food and water. Although there are reviews on the occurrence, fate and behaviour of parabens in the environment, they largely omit toxicity and removal aspects. This review therefore, presents recent reports on the acute and chronic toxicity of parabens, their estrogenic agonistic and antagonistic activity and also their relationship with antimicrobial resistance. This article further X-rays several techniques that have been employed for the removal of parabens in water and their drawbacks including adsorption, biodegradation, membrane technology and advanced oxidation processes (AOPs). The heterogeneous photocatalytic process (one of the AOPs) appears to be more favoured for removal of parabens due to its ability to mineralize parabens in water. However, more work is needed to improve this ability of heterogeneous photocatalysts. Perspectives that will be relevant for future scientific studies and which will drive policy shift towards the presence of parabens in our drinking waters are also offered. It is hoped that this review will elicit some spontaneous actions from water professionals, scientists and policy makers alike that will provide more data, effective technologies, and adaptive policies that will address the growing threat of the presence of parabens in our environment with respect to human health.

Toxicity and sublethal effects of methylparaben on zebrafish (Danio rerio) larvae and adults

Among the parabens, methylparaben (MeP) is the most commonly found in personal care products. Due to the continuous use of MeP and low removal efficiency by wastewater treatment plants (WWTPs), it reaches aquatic environments, where it is incorporated by organisms inhabiting these waters. The present study aimed to evaluate the effects of MeP on the zebrafish Danio rerio larvae and adults through toxicity tests and physiological and biochemical biomarkers in order to assess possible harmful effects of MeP. For biomarker measurements, fish were exposed to the environmental concentration of 30 μg/L of MeP and the non-effect concentration (NOEC) estimated for larvae (60 mg/L) and adult (50 mg/L) in toxicity tests. The median lethal concentration (LC₅₀) of MeP was 105.09 mg/L for adults and 211.12 mg/L for larvae. These values unexpectedly indicated that adults were more sensitive to MeP compared to larvae. In adult fish, exposure to 50 mg/L MeP induced a significant decrease in phase 1 biotransformation (ethoxyresorufin O-deethylase activity) and an increase in lipoperoxidation (LPO) in gills, as well as an increase in frequency of micronuclei in erythrocytes of these fish. Biomarkers results were integrated (integrated biomarker response [IBR] index), and it observed lower IBR scores in tissues of fish exposed to MeP, suggesting a suppression of biological responses. In addition, LPO contributed mostly to the IBR score estimated for gills of fish exposed to 50 mg/L MeP. Based on LPO quantity, sublethal exposure of MeP (30 μg/L and 60 mg/L) did not cause toxicity to larvae. Hence, we investigated whether the difference in sensitivity between adults and larvae could be associated with the antimicrobial action of MeP that could affect the intestinal microbiota of adults. We only found an increase in the number of carbon sources consumed by them without effects on diversity and abundance. This outcome can be considered an adaptation to environmental stress, but not a negative effect. However, the LPO and genotoxicity caused by MeP to zebrafish adults call direct attention to the importance of regulating the presence of this compound in the environment and improve cleaning processes adopted by WWTP.

A review on effective removal of emerging contaminants from aquatic systems: Current trends and scope for further research

Wastewater is water that has already been contaminated by domestic, industrial and commercial activity that needs to be treated before it could be discharged into some other water bodies to avoid even more groundwater contamination supplies. It consists of various contaminants like heavy metals, organic pollutants, inorganic pollutants and Emerging contaminants. Research has been doing on all types of contaminates more than a decade, but this emerging contaminants is the contaminants which arises mostly from pharmaceuticals, personal care products, hormones and fertilizer industries. The majority of emerging contaminants did not have standardized guidelines, but may have adverse effects on human and marine organisms, even at smaller concentrations. Typically, extremely low doses of emerging contaminants are found in the marine environment and cause a potential risk to the aquatic animals living there. When contaminants emerge in the marine world, they are potentially toxic and pose many risks to the health of both man and livestock. The aim of this article is to review the Emerging contaminate sources, detection methods and treatment methods. The purpose of this study is to consider the adsorption as a beneficial treatment of emerging contaminants also advanced and cost effective emerging contaminates treatment methods.

Contamination, source and potential risks of pharmaceuticals and personal products (PPCPs) in Baiyangdian Basin, an intensive human intervention area, China

The presence of pharmaceuticals and personal care products (PPCPs) has become a global concern, as it poses a threat to the environment, especially to the aquatic ecosystem. This study focused on 30 PPCPs found in the Baiyangdian basin of the Xiong'an New Area, in the core of Beijing-Tianjin-Hebei region, with intensive human interventions during two seasons. In general, 30 PPCPs were all frequently detected, ranging from 42.3 to 7710 ng/L in May and 48.9 to 1300 ng/L in November. Sulfamethoxazole, ofloxacin, anhydro-erythromycin, carbamazepine, caffeine, and were screened as the predominant PPCPs. The rivers input was an essential source of PPCPs. The source apportionment with a series of analytical methods revealed that domestic sewage was the primary source, and untreated water also crucial for PPCPs contamination. The risk assessment suggested carbamazepine, caffeine, ofloxacin, and anhydro-erythromycin exhibited relatively high ecological risks for protecting most species such as algae, fish, and flowers in the aquatic ecosystem, especially near the outlet of WWTPs. Thus, management strategies for such PPCPs will be needed. Intensive human interventions, including a prohibition of fish breeding, water diversion project, and wastewater treatment in villages, were having an effective role in alleviating PPCPs contamination.