Estrogenic activity, chemical levels and health risk assessment of municipal distribution point water from Pretoria and Cape Town, South Africa

Estrogenic compounds in drinking water: A systematic review and risk analysis

Estrogenic compounds are the endocrine disruptors that receive major attention because of their ability to imitate the natural female hormone, 17β-estradiol and cause adverse effects on the reproductive system of animals. The presence of estrogenic compounds in drinking water is a warning to assess the risks to which human beings are exposed. The present work has the objectives of carrying out a systematic review of studies that investigated estrogenic compounds in drinking water around the world and estimate the human health and estrogenic activity risks, based on the concentrations of each compound reported. The systematic review returned 505 scientific papers from the Web of Science®, SCOPUS® and PubMED® databases and after careful analysis, 45 papers were accepted. Sixteen estrogenic compounds were identified in drinking water, from the classes of hormones, pharmaceutical drugs and personal care products, plasticizers, corrosion inhibitors, pesticides and surfactants. Di-(2-ethylhexyl) phthalate (DEHP) was the compound found at the highest concentration, reaching a value of 1.43 mg/L. Non-carcinogenic human health risk was classified as high for 17α-ethynilestradiol and DEHP, medium for dibutyl phthalate, and low for bisphenol A. The estrogenic activity risks were negligible for all the compounds, except DEHP, with a low risk. None of the estrogenic compounds presented an unacceptable carcinogenic risk, due to estrogenic activity. However, the risk assessment did not evaluate the interactions between compounds, that occurs in drinking water and can increase the risks and adverse effects to human health. Nonetheless, this study demonstrates the need for improvement of drinking water treatment plants, with more efficient technologies for micropollutant removal.

Emerging organic contaminants in drinking water systems: Human intake, emerging health risks, and future research directions

Few earlier reviews on emerging organic contaminants (EOCs) in drinking water systems (DWS) focused on their detection, behaviour, removal and fate. Reviews on multiple exposure pathways, human intake estimates, and health risks including toxicokinetics, and toxicodynamics of EOCs in DWS are scarce. This review presents recent advances in human intake and health risks of EOCs in DWS. First, an overview of the evidence showing that DWS harbours a wide range of EOCs is presented. Multiple human exposure to EOCs occurs via ingestion of drinking water and beverages, inhalation and dermal pathways are discussed. A potential novel exposure may occur via the intravenous route in dialysis fluids. Analysis of global data on pharmaceutical pollution in rivers showed that the cumulative concentrations (μg L-1) of pharmaceuticals (mean ± standard error of the mean) were statistically more than two times significantly higher (p = 0.011) in South America (11.68 ± 5.29), Asia (9.97 ± 3.33), Africa (9.48 ± 2.81) and East Europe (8.09 ± 4.35) than in high-income regions (2.58 ± 0.48). Maximum cumulative concentrations of pharmaceuticals (μg L-1) decreased in the order; Asia (70.7) had the highest value followed by South America (68.8), Africa (51.3), East Europe (32.0) and high-income regions (17.1) had the least concentration. The corresponding human intake via ingestion of untreated river water was also significantly higher in low- and middle-income regions than in their high-income counterparts. For each region, the daily intake of pharmaceuticals was highest in infants, followed by children and then adults. A critique of the human health hazards, including toxicokinetics and toxicodynamics of EOCs is presented. Emerging health hazards of EOCs in DWS include; (1) long-term latent and intergenerational effects, (2) the interactive health effects of EOC mixtures, (3) the challenges of multifinality and equifinality, and (4) the Developmental Origins of Health and Disease hypothesis. Finally, research needs on human health hazards of EOCs in DWS are presented.

Ecotoxicological evaluation of surface waters in Northern Namibia

The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them.

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.

Prevalence of Endocrine Disrupting Chemicals in the urban wastewater treatment systems of Dehradun, India: Daunting presence of Estrone

We quantified the occurrences and seasonal variations of the target endocrine disrupting chemicals (EDCs) at four (two major municipals, and two academic institutions) WWTPs in Dehradun city, Uttarakhand, India. The results showed estrone in higher concentrations at μgL-1 levels in influent among the WWTPs, compared to triclosan (TCS) at ngL-1 levels. An astounding concentration of 123.95 μgL-1 was recorded for the estrone in the influent, which is to date the highest ever recorded, globally. Statistical data treatment was performed to test the distribution of the data (Shapiro-Wilk, Anderson-Darling, Lilliefors, and Jarque-Bera tests), and the significant difference between the mean of the wastewater sample population (ANOVA: F statistics, p values, Mann-Whitney test, Tukey's and Dunn's post hoc analysis). Statistical data treatment indicated EDCs concentration with a bi-modal distribution. The Shapiro-Wilk, Anderson-Darling, Lilliefors, and Jarque-Bera tests elucidate a non-normal distribution for the EDCs sample data. A statistically significant difference (F = 8.46; p < 0.0001) in the seasonal data for the abundance of the target EDCs at the WWTPs have been observed. Highest and significantly different mean EDCs concentrations were recorded during the monsoon, compared to the spring (p = 0.025) and summer (p = 0.0004) seasons in the influent waters. The mean influent concentrations of TCS and estrone in monsoon were 66.45 ngL-1 and 78.02 μgL-1, respectively. Maximum removals were recorded for TCS, while maximum negative removal of ∼293% was observed for estrone in the WWTPs. Particularly, the high levels of estrone in the wastewater pose a significant threat as estrone presence could be led to feminization, dysregulation of reproduction in organisms, and carcinogenesis processes in the environment. This study critically highlights the limitation of the WWTPs in the treatment, degradation, and assimilation of EDCs leading to their hyperaccumulation at WWTP effluents, thereby posing a substantial threat to nearby aquatic ecosystems, human health, and the ecological balance of the region.

Assessment of endocrine disruptor pollutants and their metabolites in environmental water samples using a sustainable natural deep eutectic solvent-based analytical methodology

In this work, an evaluation of the occurrence of fifteen phthalates, four metabolites and one adipate in different groundwater, seawater and wastewater samples has been carried out due to their relevance on human health as they act as endocrine disruptors. For this purpose, a sustainable, fast and easy-handling vortex-assisted liquid-liquid microextraction method using a natural hydrophobic deep eutectic solvent based on menthol and carvacrol as extraction agent, combined with ultra-high performance liquid chromatography-mass spectrometry technique, has been developed and applied for the first time. An optimization was performed to evaluate four important factors affecting the extraction performance, and an analytical validation was carried out in terms of matrix effect, linearity, extraction efficiency, and sensitivity. Recovery values were obtained in the range 72-119% for all analytes (except for monoethyl phthalate: 61.1-72.3%) with relative standard deviation values lower than 17%. Limits of quantification were found between 0.91 and 8.09 μg L-1. As a result of the assessment of 31 different environmental water samples, monoethyl phthalate, diethyl phthalate, dibutyl phthalate and bis (2-ethylhexyl) phthalate were detected and quantified at different concentrations in the range 2.59-21.17 μg L-1 in 6 samples, and diallyl phthalate, butyl benzyl phthalate, dipentyl phthalate, dicyclohexyl phthalate, dihexyl phthalate and bis (2-ethylhexyl) adipate were detected in 20 more, showing the exposition of the population to these hazardous substances.

Microbial degradation and transformation of PPCPs in aquatic environment: A review

The Pharmaceuticals and Personal Care Products (PPCPs) presence at harmful levels has been identified in aquatic ecosystems all over the world. Currently, PPCPs are more common in aquatic regions and have been discovered to be extremely harmful to aquatic creatures. Waste-water treatment facilities are the primary cause of PPCPs pollution in aquatic systems due to their limited treatment as well as the following the release of PPCPs. The degree of PPCPs elimination is primarily determined by the method applied for the remediation. It must be addressed in an eco-friendly manner in order to significantly improve the environmental quality or, at the very least, to prevent the spread as well as effects of toxic pollutants. However, when compared to other methods, environmentally friendly strategies (biological methods) are less expensive and require less energy. Most biological methods under aerobic conditions have been shown to degrade PPCPs effectively. Furthermore, the scientific literature indicates that with the exception of a few extremely hydrophobic substances, biological degradation by microbes is the primary process for the majority of PPCPs compounds. Hence, this review discusses about the optimistic role of microbe concerned in the degradation or transformation of PPCPs into non/less toxic form in the polluted environment. Accordingly, more number of microbial strains has been implicated in the biodegradation/transformation of harmful PPCPs through a process termed as bioremediation and their limitations.

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.

Endocrine-disrupting substances: I. Relative risks of PFAS in drinking water

Concentrations of per and polyfluorinated alkyl substances (PFAS) in drinking water are significantly lower than in vivo levels of the native target hormone. These concentrations are orders of magnitude lower than the hormone in question, particularly when corrected for transactivation. A pregnant woman can excrete about 7,000 μg/day of total estrogens. A low-dose oral contraceptive pill contains 20 μg estradiol. Soy-based baby formula contains phytoestrogens equivalent to a low-dose oral contraceptive pill. A woman on a low-dose oral hormone replacement therapy consumes about 0.5-2 mg/day of one or more estrogens. The levels of endocrine-disrupting substances (EDSs) exposure by oral, respiratory, or dermal routes have the potential to make removing PFAS from drinking water due to its estrogenic activity divert valuable resources. These levels become even less of a threat when their estrogenic potencies are compared with those of the target hormones present as contaminants in water and even more so when compared with levels commonly present in human tissues. The fact that PFAS constitute a tiny fraction compared to exposure to phytoestrogens makes the effort even more insignificant. If PFAS are to be removed from drinking water, it is not due to their estrogenic activity.

Bottled water contaminant exposures and potential human effects

BACKGROUND

Bottled water (BW) consumption in the United States and globally has increased amidst heightened concern about environmental contaminant exposures and health risks in drinking water supplies, despite a paucity of directly comparable, environmentally-relevant contaminant exposure data for BW. This study provides insight into exposures and cumulative risks to human health from inorganic/organic/microbial contaminants in BW.

METHODS

BW from 30 total domestic US (23) and imported (7) sources, including purified tapwater (7) and spring water (23), were analyzed for 3 field parameters, 53 inorganics, 465 organics, 14 microbial metrics, and in vitro estrogen receptor (ER) bioactivity. Health-benchmark-weighted cumulative hazard indices and ratios of organic-contaminant in vitro exposure-activity cutoffs were assessed for detected regulated and unregulated inorganic and organic contaminants.

RESULTS

48 inorganics and 45 organics were detected in sampled BW. No enforceable chemical quality standards were exceeded, but several inorganic and organic contaminants with maximum contaminant level goal(s) (MCLG) of zero (no known safe level of exposure to vulnerable sub-populations) were detected. Among these, arsenic, lead, and uranium were detected in 67 %, 17 %, and 57 % of BW, respectively, almost exclusively in spring-sourced samples not treated by advanced filtration. Organic MCLG exceedances included frequent detections of disinfection byproducts (DBP) in tapwater-sourced BW and sporadic detections of DBP and volatile organic chemicals in BW sourced from tapwater and springs. Precautionary health-based screening levels were exceeded frequently and attributed primarily to DBP in tapwater-sourced BW and co-occurring inorganic and organic contaminants in spring-sourced BW.

CONCLUSION

The results indicate that simultaneous exposures to multiple drinking-water contaminants of potential human-health concern are common in BW. Improved understandings of human exposures based on more environmentally realistic and directly comparable point-of-use exposure characterizations, like this BW study, are essential to public health because drinking water is a biological necessity and, consequently, a high-vulnerability vector for human contaminant exposures.

Emerging contaminants migration from pipes used in drinking water distribution systems: a review of the scientific literature

Migration of emerging contaminants (ECs) from pipes into water is a global concern due to potential human health effects. Nevertheless, a review of migration ECs from pipes into water distribution systems is presently lacking. This paper reviews, the reported occurrence migration of ECs from pipes into water distribution systems in the world. Furthermore, the results related to ECs migration from pipes into water distribution systems, their probable sources, and their hazards are discussed. The present manuscript considered the existing reports on migration of five main categories of ECs including microplastics (MPs), bisphenol A (BPA), phthalates, nonylphenol (NP), perfluoroalkyl, and polyfluoroalkyl substances (PFAS) from distribution network into tap water. A focus on tap water in published literature suggests that pipes type used had an important role on levels of ECs migration in water during transport and storage of water. For comparison, tap drinking water in contact with polymer pipes had the highest mean concentrations of reviewed contaminants. Polyvinyl chloride (PVC), polyamide (PA), polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) were the most frequently detected types of microplastics (MPs) in tap water. Based on the risk assessment analysis of ECs, levels of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) were above 1, indicating a potential non-carcinogenic health risk to consumers. Finally, there are still scientific gaps on occurrence and migration of ECs from pipes used in distribution systems, and this needs more in-depth studies to evaluate their exposure hazards on human health.

Occurrence of legacy and replacement plasticizers, bisphenols, and flame retardants in potable water in Montreal and South Africa

The occurrence of thirty-nine contaminants including plasticizers, bisphenols, and flame retardants in potable water from Montreal and South Africa was analyzed to determine their presence and concentrations in different water sources. In Montreal, five bottled water (BW) brands and three drinking water treatment plants (DWTP) were included. In South Africa, water was sampled from one urban DWTP located in Pretoria, Gauteng, and one rural DWTP located in Vhembe, along with water from the same rural DWTP which had been stored in small and large plastic containers. A combination of legacy compounds, typically with proven toxic effects, and replacement compounds was investigated. Bisphenols, Dechlorane-602, Dechlorane-603, and s-dechlorane plus (s-DP) were not detected in any water samples, and a-dechlorane plus (a-DP) was only detected in one sample from Pretoria at a concentration of 1.09 ng/L. Lower brominated polybrominated diphenyl ethers (PBDE)s were detected more frequently than higher brominated PBDEs, always at low concentrations of <2 ng/L, and total PBDE levels were statistically higher in South Africa than in Montreal. Replacement flame retardants, organophosphate esters (OPEs), were detected at statistically higher concentrations in Montreal's BW (68.56 ng/L), drinking water (DW) (421.45 ng/L) and Vhembe (198.33 ng/L) than legacy PBDEs. Total OPE concentrations did not demonstrate any geographical trend; however, levels were statistically higher in Montreal's DW than Montreal's BW. Plasticizers were frequently detected in all samples, with legacy compounds DEHP, DBP, and replacement DINCH being detected in 100 % of samples with average concentrations ranging from 6.89 ng/L for DEHP in Pretoria to 175.04 ng/L for DINCH in Montreal's DW. Total plasticizer concentrations were higher in Montreal than in South Africa. The replacement plasticizers (DINCH, DINP, DIDA, and DEHA) were detected at similar frequencies and concentrations as legacy plasticizers (DEHP, DEP, DBP, MEHP). For the compounds reported in earlier studies, the concentrations detected in the present study were similar to other locations. These compounds are not currently regulated in drinking water but their frequent detection, especially OPEs and plasticizers, and the presence of replacement compounds at similar or higher levels than their legacy compounds demonstrate the importance of further investigating the prevalence and the ecological or human health effects of these compounds.

Towards regulation of Endocrine Disrupting chemicals (EDCs) in water resources using bioassays - A guide to developing a testing strategy

Endocrine disrupting chemicals (EDCs) are found in every environmental medium and are chemically diverse. Their presence in water resources can negatively impact the health of both human and wildlife. Currently, there are no mandatory screening mandates or regulations for EDC levels in complex water samples globally. Bioassays, which allow quantifying in vivo or in vitro biological effects of chemicals are used commonly to assess acute toxicity in water. The existing OECD framework to identify single-compound EDCs offers a set of bioassays that are validated for the Estrogen-, Androgen-, and Thyroid hormones, and for Steroidogenesis pathways (EATS). In this review, we discussed bioassays that could be potentially used to screen EDCs in water resources, including in vivo and in vitro bioassays using invertebrates, fish, amphibians, and/or mammalians species. Strengths and weaknesses of samples preparation for complex water samples are discussed. We also review how to calculate the Effect-Based Trigger values, which could serve as thresholds to determine if a given water sample poses a risk based on existing quality standards. This work aims to assist governments and regulatory agencies in developing a testing strategy towards regulation of EDCs in water resources worldwide. The main recommendations include 1) opting for internationally validated cell reporter in vitro bioassays to reduce animal use & cost; 2) testing for cell viability (a critical parameter) when using in vitro bioassays; and 3) evaluating the recovery of the water sample preparation method selected. This review also highlights future research avenues for the EDC screening revolution (e.g., 3D tissue culture, transgenic animals, OMICs, and Adverse Outcome Pathways (AOPs)).

Assessing a co-culture fungal granule ability to remove pharmaceuticals in a sequencing batch reactor

Biodegradation of carbamazepine (CBZ), diclofenac sodium (DCF) and ibuprofen (IBP) was evaluated through fungal granules development in a sequencing batch reactor (SBR). Fungal granules were developed in co-culture of T. polyzona, A. niger, T. longibrachiatum, M. circinelloides and R. microsporus at a retention time (RT) of 2 days and 1 day. Ligninolytic enzymes [laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP)] were determined. Removal of pharmaceuticals was assessed and metabolites identified using the SPE-UPLC-QToF/MS methods. A pH range of 3-4.6 was found to improve the granulation development from day 6 and the production of ligninolytic enzymes [MnP (253.00 ± 14.19 U/L), Lac (111.58 ± 10.00 U/L) and LiP (95.25 ± 8.22 U/L)]. At steady-state, a removal of 97.41±0.25%, 99.83±0.14%, and 99.91±0.08 were achieved at an RT of 2 days for CBZ, DCF, and IBP, respectively, and of 91.94±0.05%, 99.31±0.12% and 97.72±0.23% at an RT of 1 days for the same PhCs. A variety of chemical reactions have been proposed for degradation pathways catalysed by enzyme-producing fungi, generating fragment ions of intermediate compounds. This study is highly relevant for cost-effective and environmentally friendly wastewater treatment processes in water scare countries.

Pollution Characteristics and Risk Prediction of Endocrine Disruptors in Lakes of Wuhan

As a new and ubiquitous trace organic pollutant, endocrine-disrupting compounds (EDCs) can cause endocrine-disrupting effects on organisms even at low levels. However, little information is available on the resource and assessment of EDC risks in the water environment. The study area was selected based on the paucity of information on the pollution status of inland lakes. Wuhan has numerous and diverse types of lakes which receive micropollutants from different pathways. In this study, the spatial distribution, occurrence, quantity and ecological risks of EDCs in 12 lakes were investigated. Five EDCs, including 17-alpha-ethinylestradiol (17α-EE₂), estrone (E₁), β-estradiol (β-E₂), estriol (E₃) and bisphenol A (BPA) were detected in surface waters. The distribution of EDC content in the lakes was ordered as follows: exurban zone < suburban area < urban areas. The pollution sources in remote lakes mainly included agricultural and aquaculture wastewater, while those in suburban and urban areas included domestic or industrial wastewater. Areas with higher EDC content were frequently related to agricultural activities, aquaculture water or dense populations. Water quality parameters, including dissolved oxygen, pH and water temperature, were significantly related to the occurrence and distribution of EDCs in the lakes. Risk assessment demonstrated that the occurrence of EDCs posed minimum to medium risk to aquatic organisms in the lakes. The results showed that the lakes faced a threat hormone pollution though it was at lower doses and, thus, the ecological risk of EDCs should be considered in future environmental policies and decisions in China.

Phthalate Esters in Tap Water, Southern Thailand: Daily Exposure and Cumulative Health Risk in Infants, Lactating Mothers, Pregnant and Nonpregnant Women

Human exposure to phthalate esters (PAEs) via drinking water has generated public health concerns due to their endocrine disruptive abilities. This study reports on the occurrence and fate of six PAEs in raw and tap water samples collected from provincial waterworks located in Songkhla Province, Southern Thailand. In addition, the daily exposure and cumulative health risk of susceptible populations due to drinking tap water were evaluated by using four different reference dose (RfDs) sources. The maximum concentrations of PAEs in raw water were between 1.68 and 4.84 and 0.52 and 1.24 µg/L in tap water. Moreover, the levels of PAEs in the tap water samples indicated the poor PAEs removal efficiency of the conventional treatment process (59.9-69.1%). The contribution of water to the daily intake of PAEs did not exceed 0.37% in all the groups. Furthermore, both the individual and cumulative risk assessment showed negligible noncarcinogenic and antiandrogenic risk for all the groups. Nevertheless, the cumulative risk showed an increasing trend in the order of infants > lactating mothers > pregnant women > nonpregnant women, suggesting that infants are more vulnerable. In additional, the newly proposed RfDAA yielded higher hazard quotient and hazard index estimates, which indicates it is a more sensitive tool than other RfDs for the assessment of the individual and mixture risk of pollutants. The carcinogenic risk of DEHP was acceptable in every group. However, we recommend a future cumulative risk assessment of vulnerable groups considering their simultaneous exposure to all chemicals that have antiandrogenic effects via tap water.

Assessing the Fungal Simultaneous Removal Efficiency of Carbamazepine, Diclofenac and Ibuprofen in Aquatic Environment

Unused pharmaceutical compounds (PhCs) discharged into the aquatic environment have been regarded as emerging pollutants due to potential harmful effects on humans and the environment. Microbial bioremediation is considered as a viable option for their removal from wastewater. The aim of this study was to assess the simultaneous removal of carbamazepine (CBZ), diclofenac (DCF) and ibuprofen (IBP) by previously isolated fungi (Aspergillus niger, Mucor circinelloides, Trichoderma longibrachiatum, Trametes polyzona, and Rhizopus microsporus). The tolerance to PhCs was conducted by tracking the fungal mycelium mat diameters in solid media and its dry biomass in liquid media, at the drug concentration range of 0.1 to 15 mg/L. The fungal enzymatic activities were determined for lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac), respectively. The PhC removal efficiency of the fungi was assessed in aerated batch flasks and the drug concentrations and intermediate compounds formation were determined by using SPE-UPLC/MS. A tolerance over 70% was recorded for all the fungi at drug concentration of 0.1 mg/L. Manganese peroxidase was produced by all the fungi with very low amount of LiP, while all the enzymes were produced by T. polyzona. The pH of 4.3, temperature 37 ± 1.5°C and incubation time of 6 days were the optimum parameters for the fungal enzymatic activities. The best removal of CBZ (87%) was achieved by R. microsporus after 10 days. Between 78 and 100% removal of DCF was observed by all the fungi after 24 h, while 98% of IBP was removed after 2 days by M. circinelloides. Only a few intermediate compounds were identified after 3 days and disappeared after 10 days of incubation. This study demonstrated that apart from the basidiomycetes, the ascomycetes and zygomycetes are also producers of ligninolytic enzymes and have the ability to biodegrade emerging pollutants such as PhCs.

Water intake meets the Water from inside the human body – physiological, cultural, and health perspectives - Synthetic and Systematic literature review

Background. The average adult human body of 70 kilograms consists in about 67.85% water distributed evenly to an average of 70 % in all major organs of the body: skin, muscles, brain, spinal cord, liver, heart, lungs, spleen, kidneys, pancreas and gastro-intestinal tract. A smaller percentage is found in the bones (30%), teeth (5%) and fat tissue (50%). Objective. This review article attempts to present different perspectives on the physiological properties of water in the human body. We describe from the ancient Chinese medicine theory about water being one of the 5 elements of nature and its harmonious interrelation with the other elements in order to balance the human body, to the successful experiments of researchers which demonstrated waters’ capability to change its molecular structure based on feelings, intentions and energy it was exposed to. We briefly describe the role of water for the human body and what effects can the lack of it have, especially dehydration with all the phases of severity. Also, we present the health benefits of drinking water and which type of water is best to consume. We shorty review the different types of natural mineral waters in Romania and the importance of the Romanian researches for balneology and how the waters cand be administrated in crenotherapy for different types of pathologies. Methods. To elaborate our systematic review, we have searched for relevant open access articles and review articles in ISI Web of Science, published from January 2017 until August 2021. The terms used were water AND health in the title. Articles were excluded in the second phase if they did not reach the relevance citation criterion. The eligible articles were analyzed in detail regarding water importance for human health. Results. Our search identified, first, 548 articles. After applying a PEDro like selection filter and, we selected 93 articles with a minimum of 8 points on our PEDro like filtering scale (good, very good, and excellent articles with a minimum of 5 citations per year). Detailed analysis of the 93 selected articles has conducted us to the elimination of 33 of them as being on a different subject than that of our article. To the 60 full articles retained for this systematic and synthetic article, we have added 10 articles found through a separate Google search, as being considered of high relevance for our subject and necessary to be included. Conclusions. Water is essential for the entire planet and also indispensable for the survival of the human body. Keywords: water intake, water balance, body water, water molecular structure, dehydration, crenotherapy

Bisphenol A in Africa: A review of environmental and biological levels

Bisphenol A (BPA) is a synthetic ubiquitous environmental toxicant present in many industrial and consumer products. BPA is recognized as an endocrine-disrupting chemical (EDC), and its mechanisms of perturbation of the physiological process include interference with hormone pathways and epigenetic modifications. An increase in industrial productions and food packaging across Africa has resulted in increased utilization of BPA-containing products with a concomitant increase in environmental bioaccumulation and human exposure. In order to assess the extent of this bioaccumulation, we identified, collated, and summarized the levels of BPA that have been reported across Africa. To achieve this aim, we performed a systematic search of four indexing databases to identify articles and extracted the necessary data from the selected articles. Of the 42 publications we retrieved, 42% were on water samples, 22% on food, 20% on human biological fluids, 10% on sediments, soils, and sludge and 6% on consumer and personal care products (PCPs). The highest level of BPA reported in literature across Africa was 251 ng/mL, 384.8 ng/mL, 937.49 ng/g, 208.55 ng/mL, 3,590 μg/g, and 154,820 μg/g for water, wastewater, food, biological fluids, consumer and PCPs, and semisolids, respectively. This review presented a comparative perspective of these levels relative to regulatory limits and levels reported from other continents. Finally, this review highlighted critical needs for the regulation of BPA across Africa in order to stem its environmental and toxicological impact. We hope that this review will stimulate further research in understanding the impact of BPA on health outcomes and wellbeing across Africa.

Legislation against endocrine-disrupting compounds in drinking water: essential but not enough to ensure water safety

Since the last several decades, there has been a growing concern on the presence of endocrine-disrupting compounds (EDCs) in potable water due to their negative impacts on public health of mankind. As such, more and more EDCs have been regulated in many national drinking water quality standards. Given this situation, this work attempted to deliberately offer new insights into some remaining scientific challenges, i.e., (1) what should the allowable EDC concentration be in drinking water?; (2) should the main chlorinated byproducts of EDCs be regulated in potable water?; and (3) what concentration should be regulated for each chlorinated EDC? It is expected that these could help to better design the water quality regulations for EDCs.

Emerging contaminants in South African water environment- a critical review of their occurrence, sources and ecotoxicological risks

The release of emerging contaminants (ECs) to the environment is a serious concern due to its health implications on humans, aquatic species, and the development of anti-microbial resistance. This review focuses on the critical analysis of available literature on the prevalence of ECs in the aquatic environment and their removal from wastewater treatment plants (WWTPs) in South Africa. Besides, a risk assessment is performed on the reported ECs from the South African surface water to augment the knowledge towards mitigation of EC pollution, and prioritisation of ECs to assist future monitoring plans and regulation framework. A zone wise classification approach was carried out to identify the spatial inferences and data deficiencies that revealed a non-uniformity in the monitoring of ECs throughout South Africa, with few zones rendering no data. The overarching data mining further revealed that unmanaged urine diverted toilets could be a potential source of EC pollution to groundwater in South Africa. Based on the available literature, it can be deduced that the complete adoption of EC management practices from developed countries might only contribute partly in the mitigation of EC pollution in South Africa. Therefore, an EC monitoring programme specific to the country is recommended which should be based on their occurrence levels, sources and removal in WWTPs.

Endocrine-disruptive chemicals as contaminants of emerging concern in wastewater and surface water: A review

Population growth followed by rapid development of industrialisation has caused serious environmental pollution with contaminants of emerging concern found in wastewater and surface water. As one of the most important resources for human survival, water is daily polluted by endocrine-disruptive chemicals (EDCs) including pharmaceuticals and personal care products, organic pollutants and heavy metals. Even at low concentrations in water bodies, chronic exposure to EDCs can cause adverse effects on human and environment health. The main concern with EDCs is the diseases they can generate in humans or wildlife by affecting the function of hormones in the body. Problems in the reproductive system, thyroid problems, Alzheimer's, cancer and obesity are some of the major effects of EDCs in humans. In wildlife, the reproductive system may be affected, including its levels of hatchability and vitellogenin. The efforts of the present review are on emphasising on the environmental concern on the occurrence and risk assessment of EDCs, their harmful effects in the ecosystem, human life, and wildlife, as a result of their incomplete removal from wastewater treatment plants. The review focuses on studies conducted in South Africa highlights the use of fungal bioreactors as a low-cost and eco-effective environmentally friendly wastewater treatment processes.

Screening of estrogenic endocrine-disrupting chemicals in meat products based on the detection of vitellogenin by enzyme-linked immunosorbent assay

Vitellogenin (VTG) is typically produced by females but when present in males can indicate contamination with estrogenic endocrine-disrupting chemicals (EDCs). Here we used primary hepatocytes isolated from male crucian carp uncontaminated with estrogenic EDCs as a culture model. Nine EDCs were used for validation, and an enzyme-linked immunosorbent assay (ELISA) was used to quantify VTG production by primary hepatocytes. The lower limit of detection of 17β-E2, DES, and HES using the method was 10^-12 M. Fresh pork was roasted, and non-hydrolytic acetonitrile-vortexing was used to extract potential estrogenic EDCs. The extracted substances were separated by thin-layer chromatography (TLC), and dimethyl terephthalate present in roast pork was found to induce high VTG concentrations. Therefore, the detection of VTG by ELISA provides a sensitive and reliable method for detecting known and unknown estrogenic EDCs in food products.

Agrochemicals in freshwater systems and their potential as endocrine disrupting chemicals: A South African context

South Africa is the largest agrochemical user in sub-Saharan Africa, with over 3000 registered pesticide products. Although they reduce crop losses, these chemicals reach non-target aquatic environments via leaching, spray drift or run-off. In this review, attention is paid to legacy and current-use pesticides reported in literature for the freshwater environment of South Africa and to the extent these are linked to endocrine disruption. Although banned, residues of many legacy organochlorine pesticides (endosulfan and dichlorodiphenyltrichloroethane (DDT)) are still detected in South African watercourses and wildlife. Several current-use pesticides (triazine herbicides, glyphosate-based herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and chlorpyrifos) have also been reported. Agrochemicals can interfere with normal hormone function of non-target organism leading to various endocrine disrupting (ED) effects: intersex, reduced spermatogenesis, asymmetric urogenital papillae, testicular lesions and infertile eggs. Although studies investigating the occurrence of agrochemicals and/or ED effects in freshwater aquatic environments in South Africa have increased, few studies determined both the levels of agricultural pesticides present and associated ED effects. The majority of studies conducted are either laboratory-based employing in vitro or in vivo bioassays to determine ED effects of agrochemicals or studies that investigate environmental concentrations of pesticides. However, a combined approach of bioassays and chemical screening will provide a more comprehensive overview of agrochemical pollution of water systems in South Africa and the risks associated with long-term chronic exposure.

Pharmaceuticals and personal care products in water and wastewater: a review of treatment processes and use of photocatalyst immobilized on functionalized carbon in AOP degradation

The presence of emerging contaminants such as pharmaceutical and personal care products in many aqueous matrices have been reported. One of such matrix is streams of wastewater, including wastewater treatment plants inflows and outflows and wastewater flow by-passing wastewater treatment plants. Their persistence arises from their resistant to breakdown, hence they may remain in the environment over long time, with a potential to cause adverse effects including endocrine disruption, gene toxicity, the imposition of sex organs, antibiotic resistance and many others in some aquatic organisms exposed to arrays of residues of pharmaceutical and personal care products. Among the treatment techniques, advanced oxidation processes have been reported to be a better technique through which these PPCPs can be degraded in the WWTPs. Heterogeneous photocatalysis using various photocatalyst immobilized on solid support such as activated carbon, graphene and carbon nanotubes in AOPs have been shown to be a viable and efficient method of PPCPs degradation. This is because, the performance of most WWTPs is limited since they were not designed to degrade toxic and recalcitrant PPCPs. This review highlight the occurrence, concentration of PPCPs in wastewater and the removal efficiency of heterogeneous photocatalysis of TiO2 immobilized on solid supports.

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.

Environmental Health Research in Africa: Important Progress and Promising Opportunities

The World Health Organization in 2016 estimated that over 20% of the global disease burden and deaths were attributed to modifiable environmental factors. However, data clearly characterizing the impact of environmental exposures and health endpoints in African populations is limited. To describe recent progress and identify important research gaps, we reviewed literature on environmental health research in African populations over the last decade, as well as research incorporating both genomic and environmental factors. We queried PubMed for peer-reviewed research articles, reviews, or books examining environmental exposures and health outcomes in human populations in Africa. Searches utilized medical subheading (MeSH) terms for environmental exposure categories listed in the March 2018 US National Report on Human Exposure to Environmental Chemicals, which includes chemicals with worldwide distributions. Our search strategy retrieved 540 relevant publications, with studies evaluating health impacts of ambient air pollution (n=105), indoor air pollution (n = 166), heavy metals (n = 130), pesticides (n = 95), dietary mold (n = 61), indoor mold (n = 9), per- and polyfluoroalkyl substances (PFASs, n = 0), electronic waste (n = 9), environmental phenols (n = 4), flame retardants (n = 8), and phthalates (n = 3), where publications could belong to more than one exposure category. Only 23 publications characterized both environmental and genomic risk factors. Cardiovascular and respiratory health endpoints impacted by air pollution were comparable to observations in other countries. Air pollution exposures unique to Africa and some other resource limited settings were dust and specific occupational exposures. Literature describing harmful health effects of metals, pesticides, and dietary mold represented a context unique to Africa. Studies of exposures to phthalates, PFASs, phenols, and flame retardants were very limited. These results underscore the need for further focus on current and emerging environmental and chemical health risks as well as better integration of genomic and environmental factors in African research studies. Environmental exposures with distinct routes of exposure, unique co-exposures and co-morbidities, combined with the extensive genomic diversity in Africa may lead to the identification of novel mechanisms underlying complex disease and promising potential for translation to global public health.

Occurrence and treatment of contaminants of emerging concern in the African aquatic environment: Literature review and a look ahead

Awareness about the rising detection and reported (eco)toxicological effects of contaminants of emerging concern (CECs, e.g. pharmaceuticals and personal care products - PPCPs - and modern pesticides) in the aquatic environment is growing. CECs are increasingly reported in the African aquatic environment, although the amount of data available is still limited. In this work, a comprehensive review is presented on the occurrence of CECs in wastewater, sludge, surface water, sediment, groundwater and drinking water of Africa. Further attention is given to the performance of wastewater stabilization ponds (WSPs) and trickling filters (TF) with respect to CECs removal. For the first time, we also look at the state of knowledge on the performance of point-of-use technologies (POUs) regarding the removal of CECs in drinking water. Generally, CECs in Africa occur at the same order of magnitude as in the Western world. However, for particular groups of compounds and at specific locations such as informal settlements, clearly higher concentrations are reported in Africa. Whereas antiretroviral and antimalarial drugs are rarely detected in the Western world, occurrence patterns in Africa reveal concentrations up to >100 μg L^-1. Removal efficiencies of WSPs and TFs focus mainly on PPCPs and vary significantly, ranging from no removal (e.g. carbamazepine) to better than 99.9% (e.g. paracetamol). Despite the rising adoption of POUs, limited but promising information is available on their performance regarding CECs treatment in drinking water, particularly for the low-cost devices (e.g. ceramic filters and solar disinfection - SODIS) being adopted in Africa and other developing countries.

Analysis, occurrence and removal of pharmaceuticals in African water resources: A current status

Pharmaceuticals are organic compounds used in medicines for alleviation of pain. Since 2017, there has been a steady increase on the availability of information on contamination of water resources caused by pharmaceuticals in some African countries. Thus far, most environmental monitoring studies of pharmaceuticals are conducted in South Africa while there is still no available data in majority of the African countries. Therefore, the knowledge on the presence of pharmaceuticals in African water resources is still lacking. In an attempt to provide more information in this aspect, this review article seeks to critically evaluate the progress made thus far by the African scientists in the environmental monitoring and assessment of pharmaceuticals. The most studied groups of pharmaceuticals in Africa are non-steroidal anti-inflammatory drugs, antibiotics, antiretroviral drugs and steroid hormones. Various remediation studies for selected pharmaceuticals in Africa are documented in literature. In the present review, the challenges facing the African researchers or countries on providing more scientific data on the occurrence of pharmaceuticals in water are discussed. Furthermore, the gaps and recommendations for future work are given.

Data on UPLC/MS method validation for the biodegradation of pharmaceuticals and intermediates by a fungal consortium and on T47DK-Bluc reporter gene assay to assess the reduction of their estrogenic activity

In term of pharmaceutical and their intermediate compounds analysis, UPLC/MS method is a valuable equipment to achieve better confirmation on their biodegradation by fungi. The T47D-KBluc reporter gene assay is an appropriate tool to investigate to removal of estrogenic and antiestrogenic activities of pharmaceuticals and their metabolites from a synthetic wastewater. A consortium of isolated South African indigenous fungi Aspergillus niger, Mucor circinelloides, Trichoderma longibrachiatum, Trametes polyzona and Rhizopus microspores was found to perform a removal of pharmaceuticals and their metabolites and to reduce their estrogenic activity below the limit of detection in a sequencing batch reactor. Here are presented data regarding the phenolic compounds list and the method validation for UPLC/MS analysis used for selected pharmaceutical compounds namely carbamazepine, diclofenac, ibuprofen and their metabolites, as well as the T47D-KBluc bioassay using as positive control, the agonist E₂ for estrogenic activity and the antagonist ICI 182,780 for antiestrogenic activity. For better understanding of the data presented in this paper, please see the research paper “Removal of pharmaceutical’ estrogenic activity of sequencing batch reactor effluents assessed in the T47DK-Bluc reporter gene assay” [1].

Removal of pharmaceutical' estrogenic activity of sequencing batch reactor effluents assessed in the T47D-KBluc reporter gene assay

Various water treatment processes may be ineffective to remove pharmaceutical compounds (PhCs) and their by-products, leading to endocrine-disruptive activity that might be detrimental to wildlife and human health. This study investigated the degradation of carbamazepine (CBZ), diclofenac (DCF), ibuprofen (IBP), and their intermediates, as well as estrogenic activity that is not effectively removed by conventional methods. A consortium of isolated South African indigenous fungi A. niger, M. circinelloides, T. polyzona, T. longibrachiatum and R. microsporus, was used in a sequencing batch reactor (SBR) to remove PhCs, their intermediates and strongly reduce their estrogenic activity. The fungal ligninolytic enzymatic activity was determined for laccase (Lac), manganese peroxidase (MnP) and lignin peroxidase (LiP) using a spectrophotometric method. The biodegradation of PhCs and their intermediates was monitored by SPE-UPLC/MS. The in vitro estrogenic activity was assessed in the T47D-KBluc reporter gene assay. Lac, MnP and LiP production appeared to be biomass growth dependent. During a lag phase of growth, a constant biomass of about 122.04 mg/100 mL was recorded with average enzymatic activity around 63.62 U/L for Lac, 151.91 U/L for MnP and 42.12 U/L for LiP. The exponential growth phase from day 7 to day 17, was characterised by a biomass increase of 124.46 units, and an increase in enzymatic activity of 9.91 units for Lac, 99.03 units for MnP and 44.24 units for LiP. These enzymes played an important synergistic role in PhCs degradation in the cytochrome P450 system. A decrease of 13.89%, 29.7% and 16.15% in PhC concentrations was observed for CBZ, DCF and IBP, respectively, and their intermediates were identified within 4 h of incubation. The removal efficiency achieved after 24 h in the SBR was about 89.77%, 95.8% and 91.41% for CBZ, DCF and IBP, respectively. The estradiol equivalent (EEq) values of 1.71 ± 0.30 ng/L and 2.69 ± 0.17 ng/L were recorded at the start-up time and after 4 h, respectively. The presence of intermediates was found to induce estrogenic activity. The EEq values after 24 h incubation was found to be below the LoQ and below the LoD of the assay. None of the samples exhibited any anti-estrogenic activity. The fungal consortium inoculum was found to induce toxicity at a 0.4× concentration, as observed under a microscope. This study revealed that the use of the fungal consortium can remove the estrogenic activity of pharmaceutical metabolites, which appeared to be the most significant contributors to the endocrine-disrupting activity of the wastewater treatment plant effluents.

Risk-based approach in the revised European Union drinking water legislation: Opportunities for bioanalytical tools

A plethora of in vitro bioassays are developed in the context of chemical risk assessment and clinical diagnostics to test effects on different biological processes. Such assays can also be implemented in effect-based monitoring (EBM) of (drinking) water quality alongside chemical analyses. Effects-based monitoring can provide insight into risks for the environment and human health associated with exposure to (unknown) complex, low-level mixtures of micropollutants, which fits in the risk-based approach that was recently introduced in the European Drinking Water Directive. Some challenges remain, in particular those related to selection and interpretation of bioassays. For water quality assessment, carcinogenesis, adverse effects on reproduction and development, effects on xenobiotic metabolism, modulation of hormone systems, DNA reactivity, and adaptive stress responses are considered the most relevant toxicological endpoints. An evaluation procedure of the applicability and performance of in vitro bioassays for water quality monitoring, based on existing information, has been developed, which can be expanded with guidelines for experimental evaluations. In addition, a methodology for the interpretation of in vitro monitoring data is required, because the sensitivity of specific in vitro bioassays in combination with sample concentration may lead to responses of chemicals (far) below exposure concentrations that are relevant for human health effects. Different approaches are proposed to derive effect-based trigger values (EBTs), including EBTs based on (1) relative ecotoxicity potency, (2) health-based threshold values for chronic exposure in humans and kinetics of reference chemicals, and (3) read-across from (drinking) water guideline values. Effects-based trigger values need to be chosen carefully in order to be sufficiently but not overly conservative to indicate potential health effects. Consensus on the crucial steps in the selection and interpretation of in vitro bioassay data will facilitate implementation and legal embedding in the context of water quality monitoring of such assays in EBM strategies. Integr Environ Assess Manag 2019;15:126-134. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

N-propyl functionalized spherical mesoporous silica as a rapid and efficient adsorbent for steroid estrogen removal: Adsorption behaviour and effects of water chemistry

To achieve an enhanced and selective adsorption of steroid estrogens, the n-propyl functionalization was applied to the mesoporous silica material (MCM-41) according to the physico-chemical property analysis of steroid estrogens. Adsorption behaviour and water chemistry effects were evaluated with the most concerned steroid estrogens: estrone (E1), 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2) based on the materials characterization. The results showed the uptakes of E1, E2, and EE2 onto the modified MCM-41 were enhanced and accelerated by the n-propyl functionalization, which was positively correlated with the hydrophobicity of the synthesized materials. Kinetic data fitted the pseudo-second-order model well. Based on the Langmuir model, the maximum adsorption capacities of the n-propyl modified MCM-41 were up to 119.87, 88.38, and 86.91 mg g^-1 for EE2, E1, and E2, respectively. Importantly, both acid and neutral solutions were beneficial to estrogen removal, but ionic strength and humic acid did not affect the estrogen adsorption. The above results suggested that the n-propyl functionalized MCM-41 would be a promising adsorbent for the rapid and efficient removal of estrogens with the selectivity from natural organic matter like humic acid. Mechanism analysis showed the key role of hydrophobic interaction, and it also confirmed the contribution of the carbonylic lone pair electrons of E1, which helped the formation of stronger hydrogen bonds with silicon hydroxyls and enhanced the dipole-dipole interaction between E1 and the synthesized materials.

Endocrine-disrupting metabolites of alkylphenol ethoxylates - A critical review of analytical methods, environmental occurrences, toxicity, and regulation

Despite the fact that metabolites of alkylphenol ethoxylates (APEO) are classified as hazardous substances, they continue to be released into the environment from a variety of sources and are not usually monitored. Their wide use has led to an increase in the possible exposure pathways for humans, which is cause for alarm. Moreover, there is a lack of knowledge about the behaviour of these metabolites with respect to the environment and toxicity, and their biological effects on human health. The aim of this work is to give an overview of the APEO metabolites and their analysis, occurrences and toxicity in various environmental and human samples. APEO metabolites have adverse effects on humans, wildlife, and the environment through their release into the environment. Currently, there are some reviews available on the behaviour of alkylphenols in soil, sediments, groundwater, surface water and food. However, none of these articles consider their toxicity in humans and especially their effect on the nervous and immune system. This work summarises the environmental occurrences of metabolites of APEOs in matrices, e.g. water, food and biological matrices, their effect on the immune and nervous systems, and isomer-specific issues. With that emphasis we are able to cover most common occurrences of human exposure, whether direct or indirect.