New challenges in environmental analytical chemistry: Identification of toxic compounds in complex mixtures

Environmental health science research: opportunities and challenges for some developing countries in Africa

Due to ongoing developmental projects, there is a need for regular monitoring of the impact of pollutants on the environment. This review documented the challenges and opportunities in the field of environmental health sciences in some African countries. A systematic review was used to investigate opportunities and challenges in the field of environmental health science in Africa by examining published work with a specific focus on Africa. The reports showed that funding and infrastructure as the major problems. The study also highlighted recruiting study participants, retention, and compensation as a bane in the field in Africa. The absence of modern equipment also hinders research. The review, however, noted research collaboration from the region including studies on emerging pollutants such as pharmaceuticals, per and polyfluoroalkyl substances (PFAS), and microplastic (MPs) as great opportunities. The study concluded that collaboration with other continents, exchange programs and improved governmental interventions may help.

Macroinvertebrate communities respond strongly but non-specifically to a toxicity gradient derived by effect-based methods

Chemical pollution is one of the most important threats to freshwater ecosystems. The plethora of potentially occurring chemicals and their effects in complex mixtures challenge standard monitoring methods. Effect-based methods (EBMs) are proposed as complementary tools for the assessment of chemical pollution and toxic effects. To investigate the effects of chemical pollution, the ecological relevance of EBMs and the potential of macroinvertebrates as toxicity-specific bioindicators, ecological and ecotoxicological data were linked. Baseline toxicity, mutagenicity, dioxin-like and estrogenic activity of water and sediment samples from 30 river sites in central Germany were quantified with four in vitro bioassays. The responses of macroinvertebrate communities at these sites were assessed by calculating 16 taxonomic and functional metrics and by investigating changes in the taxonomic and trait composition. Principal component analysis revealed an increase in toxicity along a joint gradient of chemicals with different modes of action. This toxicity gradient was associated with a decrease in biodiversity and ecological quality, as well as significant changes in taxonomic and functional composition. The strength of the effects suggested a strong impact of chemical pollution and underlined the suitability of EBMs in detecting ecological relevant effects. However, the metrics, taxa, and traits associated with vulnerability or tolerance to toxicity were found to also respond to other stressors in previous studies and thus may have only a low potential as toxicity-specific bioindicators. Because macroinvertebrates respond integratively to all present stressors, linking both ecological and environmental monitoring is necessary to investigate the overall effects but also isolate individual stressors. EBMs have a high potential to separate the toxicity of chemical mixtures from other stressors in a multiple stressor scenario, as well as identifying the presence of chemical groups with specific modes of action.

Developing an Approach for Integrating Chemical Analysis and Transcriptional Changes to Assess Contaminants in Water, Sediment, and Fish

Pharmaceuticals in aquatic environments pose threats to aquatic organisms because of their continuous release and potential accumulation. Monitoring methods for these contaminants are inadequate, with targeted analyses falling short in assessing water quality's impact on biota. The present study advocates for integrated strategies combining suspect and targeted chemical analyses with molecular biomarker approaches to better understand the risks posed by complex chemical mixtures to nontarget organisms. The research aimed to integrate chemical analysis and transcriptome changes in fathead minnows to prioritize contaminants, assess their effects, and apply this strategy in Wascana Creek, Canada. Analysis revealed higher pharmaceutical concentrations downstream of a wastewater-treatment plant, with clozapine being the most abundant in fathead minnows, showing notable bioavailability from water and sediment sources. Considering the importance of bioaccumulation factor and biota-sediment accumulation factor in risk assessment, these coefficients were calculated based on field data collected during spring, summer, and fall seasons in 2021. Bioaccumulation was classified as very bioaccumulative with values >5000 L kg-1, suggesting the ability of pharmaceuticals to accumulate in aquatic organisms. The study highlighted the intricate relationship between nutrient availability, water quality, and key pathways affected by pharmaceuticals, personal care products, and rubber components. Prioritization of these chemicals was done through suspect analysis, supported by identifying perturbed pathways (specifically signaling and cellular processes) using transcriptomic analysis in exposed fish. This strategy not only aids in environmental risk assessment but also serves as a practical model for other watersheds, streamlining risk-assessment processes to identify environmental hazards and work toward reducing risks from contaminants of emerging concern. Environ Toxicol Chem 2024;00:1-22. © 2024 SETAC.

Innovative analytical methodologies for characterizing chemical exposure with a view to next-generation risk assessment

The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies. The use of less-conventional sampling strategies and integration of full-scan, high-resolution mass spectrometry and effect-directed analysis in environmental and human monitoring programmes have the potential to enhance the screening and identification of a wider range of chemicals of known, emerging or potential future concern. Here, we outline the key needs and recommendations identified within the European Partnership for Assessment of Risks from Chemicals (PARC) project for leveraging these innovative methodologies to support the development of next-generation chemical risk assessment.

Field-portable seawater toxicity monitoring platform using lens-free shadow imaging technology

The accidental spill of hazardous and noxious substances (HNSs) in the ocean has serious environmental and human health consequences. Assessing the ecotoxicity of seawater exposed to various HNS is challenging due to the constant development of new HNS or mixtures, and assessment methods are also limited. Microalgae viability tests are often used among the various biological indicators for ecotoxicity testing, as they are the primary producers in aquatic ecosystems. However, since the conventional cell growth rate test measures cell viability over three to four days using manual inspection under a conventional optical microscope, it is labor- and time-intensive and prone to subjective errors. In this study, we propose a rapid and automated method to evaluate seawater ecotoxicity by quantification of the morphological changes of microalgae exposed to more than 30 HNSs. This method was further validated using conventional growth rate test results. Dunaliella tertiolecta, a microalgae species without rigid cell walls, was selected as the test organism. Its morphological changes in response to HNS exposure were measured at the single cell level using a custom-developed device that uses lens-free shadow imaging technology. The ecotoxicity evaluation induced by the morphological change could be available in as little as 5 min using the proposed method and device, and it could be effective for 20 HNSs out of 30 HNSs tested. Moreover, the test results of six selected HNSs with high marine transport volume and toxicity revealed that the sensitivity of the proposed method extends to half the maximum effective concentration (EC50) and even to the lowest observed effective concentration (LOEC). Furthermore, the average correlation index between the growth inhibition test (three to four days) and the proposed morphology changes test (5 min) for the six selected HNSs was 0.84, indicating great promise in the field of various point-of-care water quality monitoring. Thus, the proposed equipment and technology may provide a viable alternative to traditional on-site toxicity testing, and the potential of rapid morphological analysis may replace traditional growth inhibition testing.

Evaluation of double-tuned single-sided planar microcoils for the analysis of small 13 C enriched biological samples using 1 H-13 C 2D heteronuclear correlation NMR spectroscopy

Microcoils provide a cost-effective approach to improve detection limits for mass-limited samples. Single-sided planar microcoils are advantageous in comparison to volume coils, in that the sample can simply be placed on top. However, the considerable drawback is that the RF field that is produced by the coil decreases with distance from the coil surface, which potentially limits more complex multi-pulse NMR pulse sequences. Unfortunately, ¹ H NMR alone is not very informative for intact biological samples due to line broadening caused by magnetic susceptibility distortions, and ¹ H-¹³ C 2D NMR correlations are required to provide the additional spectral dispersion for metabolic assignments in vivo or in situ. To our knowledge, double-tuned single-sided microcoils have not been applied for the 2D ¹ H-¹³ C analysis of intact ¹³ C enriched biological samples. Questions include the following: Can ¹ H-¹³ C 2D NMR be performed on single-sided planar microcoils? If so, do they still hold sensitivity advantages over conventional 5 mm NMR technology for mass limited samples? Here, 2D ¹ H-¹³ C HSQC, HMQC, and HETCOR variants were compared and then applied to ¹³ C enriched broccoli seeds and Daphnia magna (water fleas). Compared to 5 mm NMR probes, the microcoils showed a sixfold improvement in mass sensitivity (albeit only for a small localized region) and allowed for the identification of metabolites in a single intact D. magna for the first time. Single-sided planar microcoils show practical benefit for ¹ H-¹³ C NMR of intact biological samples, if localized information within ~0.7 mm of the 1 mm I.D. planar microcoil surface is of specific interest.

Toxicity of gabapentin-lactam on the early developmental stage of zebrafish (Danio rerio)

Gabapentin-lactam (GBP-L) is a transformation product (TP) of gabapentin (GBP), a widely used anti-epileptic pharmaceutical. Due to its high persistence, GBP-L has been frequently detected in the surface water. However, the effects of GBP-L on aquatic organisms have not been thoroughly investigated. In the present study, zebrafish (Danio rerio) embryos as a model organism were used to study the impacts of GBP-L in terms of embryos LC₅₀, spontaneous movement at 24 hpf (hours post fertilization), heartbeat rates at 48 hpf, and body length at 72 hpf, with the concentrations of GBP-L down to 0.01 μg/L, covering its environmental concentrations. Various biomarkers from nervous, antioxidant and immune systems of zebrafish larvae were analyzed, including acetylcholinesterase, acetylcholine, dopamine, gamma-aminobutyric acid, superoxide dismutase, catalase, glutathione S-transferase, C reactive protein, and lysozyme, to assess its toxicity on these systems. RT-qPCR was then used to further verify the results and explain the toxicological mechanism at the gene level. The results demonstrated that GBP-L is much more toxic than its parent compound, and could lead to adverse impacts on the aquatic organisms even at every low concentrations.

Tebuconazole-induced toxicity and the protective effect of Ficus carica extract in Neotropical fruit-eating bats

Tebuconazole (TEB) is a triazole fungicide widely used in agriculture known to cause metabolic and endocrine disorders in mammals. Several plant extracts have shown to be beneficial against pesticide effects due to their hepatoprotective, antioxidant and anti-inflammatory properties. As fruit bats play a critical role in rainforest regeneration and are constantly exposed to pesticides, we aimed at evaluating TEB-induced toxicity and the possible protective effect of the Ficus carica plant extract in Neotropical fruit-eating bats (Artibeus lituratus). Bats were captured and assigned to 4 experimental groups, offered: 1) CTL (n = 6): papaya; 2) DMSO (n = 6): papaya treated with 1.25% dimethyl sulfoxide (DMSO); 3) TEB (n = 6): papaya treated with tebuconazole (commercial formulation) 0.1%; and 4) TEBFC (n = 6): papaya treated with tebuconazole 0.1% and Ficus carica extract (20%) in DMSO (1.25%). After seven days of exposure, TEB bats showed increased lipid peroxidation, increased superoxide dismutase (SOD) and catalase (CAT) activities, vascular congestion and inflammatory infiltrate in the liver, and increased serum transaminase enzyme activities. We found the same alterations in oxidative stress parameters in the breast muscles of TEB-exposed bats. In the testes, all oxidative stress markers were increased in TEB bats and corroborate findings of histopathological and increased serum testosterone levels observed following TEB exposure. The co-administration of the fungicide with the F. carica plant extract attenuated most oxidative stress markers in exposed bats' liver and testes and decreased liver damage, but failed to revert the steroid imbalance caused by the fungicide exposure.

Treatment of a clinical analysis laboratory wastewater from a hospital by photo-Fenton process at four radiation settings and toxicity response

The photo-Fenton process was performed with four radiation settings to treat clinical analysis laboratory wastewater (CALWW) from a hospital, with the aim of evaluating its treatability and acute toxicity response in Daphnia magna and Lactuca sativa. The experiments were performed in a borosilicate bench-scale conventional reactor for 320 min. The light radiation was suspended 13 cm from the CALWW surface for mild radiation or immersed into the matrix for intense radiation. All photo-Fenton experimental conditions were set at pH 3.0, 15 mg L^-1 of Fe²⁺, and initial H₂O₂ of 300 mg L^-1. The initial Fe²⁺ concentration was converted to Fe³⁺ ion in the first 15 min of photooxidation for all processes. Furthermore, the intense radiation processes regenerated Fe²⁺ faster than other systems. Neither mild UVA-Vis nor mild UVC-Vis radiation significantly treated the organic matter or phenols. However, mild UVC-Vis resulted in a higher biodegradability transformation rate (biochemical oxygen demand/chemical oxygen demand 0.51), indicating that it could treat more recalcitrant organic matter than mild UVA-Vis. Intense radiation proved to be more efficient, with a chemical oxygen demand removal rate of 95% for intense UVA-Vis and 99% for intense UVC-Vis treatments. All treatments reduced acute toxicity in D. magna. Moreover, photo-Fenton treatment by intense UVA-Vis decreased toxicity ~98%, compared to mild and intense UVC-Vis, ~75%. Both of the mild radiation treatments inhibited the germination of L. sativa seeds. The intense UVA-Vis photo-Fenton treatment was the only setting that removed phytotoxicity, resulting in a non-significant effect, and the intense UVC-Vis treatment inhibited the seed growth.

Emerging contaminants in the water bodies of the Middle East and North Africa (MENA): A critical review

Many emerging contaminants (ECs) are not currently removed by conventional water treatment methods and consequently, often reach the aquatic environment. In the absence of proper management strategies, ECs can accumulate in water bodies, which poses potential environmental and health risks. This paper critically reviews, for the first time, the reported occurrence and treatment of ECs in the Middle Eastern and North Africa (MENA) region. The paper also provides recommendations to properly manage EC risks. In the MENA region, pharmaceuticals and personal care products (PPCPs) have been detected in surface water, seawater, groundwater, and wastewater treatment plants. A focus on surface water in the published literature suggests that studies are skewed towards worldwide trends, whereas studies on ECs in seawater are of great importance in the study region. The types of PPCPs detected in the MENA region vary, but anti-inflammatories and antibiotics dominate. In comparison, microplastics have mainly been studied in surface waters and seawater with much less focus on drinking water. The majority of microplastics in the region are secondary types resulting from the degradation of larger plastic debris; polyethylene (PE) and polypropylene (PP) fibers are the most frequently detected polymers, which are indicative of local anthropogenic sources. Research progress on ECs varies between countries, having received more attention in Iran and Tunisia. Most MENA countries have now begun monitoring water bodies for ECs; however, studies are still lacking in some countries including Sudan, Djibouti, Syria, Ethiopia, and Bahrain. Based on this review, critical knowledge gaps and research needs are identified. Countries in the MENA region require further research on a broader range of EC types. Overall, water pollution due to the use and release of ECs can be tackled by improving public awareness, public campaigns, government intervention, and advanced monitoring and treatment methods.

Reclaimed wastewater as a viable water source for agricultural irrigation: A review of food crop growth inhibition and promotion in the context of environmental change

The geographical and temporal distribution of precipitation has and is continuing to change with changing climate. Shifting precipitation will likely require adaptations to irrigation strategies, and because 35% of rainfed and 60% of irrigated agriculture is within 20 km of a wastewater treatment plant, we expect that the use of treated wastewater (e.g., reclaimed wastewater) for irrigation will increase. Treated wastewater contains various organic and inorganic substances that may have beneficial (e.g., nitrate) or deleterious (e.g., salt) effects on plants, which may cause a change in global food productivity should a large change to treated wastewater irrigation occur. We reviewed literature focused on food crop growth inhibition or promotion resulting from exposure to xenobiotics, engineered nanoparticles, nitrogen, and phosphorus, metals, and salts. Xenobiotics and engineered nanoparticles, in nearly all instances, were detrimental to crop growth, but only at concentrations much greater than would be currently expected in treated wastewater. However, future changes in wastewater flow and use of these compounds and particles may result in phytotoxicity, particularly for xenobiotics, as some are present in wastewater at concentrations within approximately an order of magnitude of concentrations which caused growth inhibition. The availability of nutrients present in treated wastewater provided the greatest overall benefit, but may be surpassed by the detrimental impact of salt in scenarios where either high concentrations of salt are directly deleterious to plant development (rare) or in scenarios where soils are poorly managed, resulting in soil salt accumulation.

Prioritization of pharmaceuticals in water environment in China based on environmental criteria and risk analysis of top-priority pharmaceuticals

Numerous studies have shown that a wide range of pharmaceuticals are present in the environment and many of their adverse biological effects on the aquatic ecosystem and human health are unknown. Due to the high population density and large number of pharmaceuticals produced and consumed in China, a systematic approach is needed to identify pharmaceuticals that require greater attention. The present study provides a ranking of pharmaceuticals in China in terms of their occurrence (O), persistence, bioaccumulation, and toxicity (PBT) based on the predicted environmental concentration (PEC). The total and partial ranking method implemented in the decision analysis by ranking techniques (DART) tool was used, which is an easy-to-use tool for the analysis of datasets. Using the DART approach, 10 pharmaceuticals were selected as priority compounds. These pharmaceuticals included antibiotics, anti-inflammatory and antilipidemic. In order to identify the characteristics of the priority pharmaceuticals, ecotoxicological endpoints were considered. The results of this study and the priority list facilitate the selection of candidate pollutants in future monitoring studies.

Metoprolol and metoprolol acid degradation in UV/H2O2 treated wastewaters: An integrated screening approach for the identification of hazardous transformation products

Advancements on analytical strategies to determine the chemicals present in treated wastewater are necessary to clearly link their occurrence with the ecotoxicity of such effluents. This study describes the development of an integrated screening approach to determine the highest number of pharmaceutical transformation products (TPs) in a single run. The identification of TPs was based on the comparison of detected features with literature sources, compound prediction tools, in-house libraries and reference standards using high-resolution mass spectrometry (HRMS). This integrated approach allowed a better estimation (in silico) of the ecotoxicological contribution of the individual TPs identified. As a proof of concept, this methodology was applied for identification of the TPs generated from metoprolol and its main human metabolite (metoprolol acid) in pure water, hospital wastewater and industrial wastewater treated by UV/H₂O₂. Twenty-four TPs with potential ecotoxicological implications were identified and their presence was pinpointed as a function of the treated wastewater. An integrated screening approach has been developed using four different screening methodologies in the same run. Additionally, the metabolite MTPA has been considered as a target pollutant in UV/H₂O₂ experiments.

Nontarget analysis: A new tool for the evaluation of wastewater processes

Strategies to determine the removal efficiency of micropollutants in wastewater treatment plants (WWTPs) are widely discussed. Especially the evaluation of the potential benefit of further advanced treatment steps such as an additional tertiary treatment based on ozonation or activated carbon have come into focus. Such evaluation strategies are often based on the removal behavior of known micropollutants via target or suspected analysis. The utilization of nontarget analysis is considered to lead to a more comprehensive picture as also unknown or not expected micropollutants are analyzed. Here, the results of an evaluation via target and nontarget analysis were compared for biological treatment (BT) processes of eleven full-scale WWTPs and three different post-treatments (PTs): one sand filter (SF) and two granular activated carbon (GAC) filters. The similarity of the determined removals from target and nontarget analysis of the BTs increased significantly by excluding easily degradable "features" from the nontarget evaluation. A similar ranking of the removal trends for the BTs could also be achieved by comparing this new subset of nontarget features with a set of nine readily to moderately biodegradable micropollutants. This observation suggests that a performance ranking of BTs based either on target or nontarget analysis is plausible. In contrast to the BTs, the evaluation of the three PTs revealed that the difference of feature removal between SF and the two GACs was small, but large for the target analytes with substantially higher removal effciencies for the GACs compared to the SF. In addition to the removal behavior, the nontarget analysis provided further information about the number and quantity of transformation products (TPs) in the effluent from the BTs. For all BTs more than half (55-67%) of the features detected in the effluent were not found in the influent. A comparable proportion of TPs was also detected after GAC and sand filtration due to their microbial activities.

Landfill leachates and wastewater of maritime origin as possible sources of endocrine disruptors in municipal wastewater

In this study, wastewater from municipal services, such as a port wastewater reception facility (PRF-WW) and a municipal solid waste plant (MSWP), was tested for the presence of the suspected endocrine-disrupting compounds phthalates (PAEs) and bisphenol A (BPA). PAEs and BPA were found in this study in high concentrations in raw wastewater obtained from passenger ships (RMT-WWs) (up to 738 μg/L and 957 μg/L, respectively) collected in the Port of Gdynia and in landfill leachates (LLs) (up to 536 μg/L and up to 2202 μg/L, respectively) from a MSWP located near Gdynia. In particular, the presence of reprotoxic di(2-ethylhexyl) phthalate (DEHP, up to 536 μg/L in LLs and up to 738 μg/L in RMT-WWs) requires further action because if this compound, as well as other PAEs and BPA, is not degraded by activated sludge microorganisms, it may reach receiving waters and adversely impact aquatic organisms. Therefore, PAEs and BPA should be removed either during the onsite pretreatment of tested industrial wastewater or during tertiary treatment at municipal wastewater treatment plants (WWTPs, representing end-of-pipe technology). Graphical abstract.

Occurrence of PPCPs in a Brazilian water reservoir and their removal efficiency by ecological filtration

The presence of PPCPs (Pharmaceuticals and Personal Care Products) in water sources and drinking water has concerned researchers in recent times. This study was carried out to evaluate the occurrence of 6 PPCPs (namely paracetamol, diclofenac, naproxen, ibuprofen, benzophenone-3 and methylparaben) in the Lobo reservoir, their degradation products, and how efficiently they were removed by 22 ecological filters, considering individual and mixture of compounds. There were 3 spiking events of PPCPs (2 μg L^-1) in the ecological filter influents conducted with a lag period of 15 days between spikes. Water samples were collected from the influent and effluent of the filters at 3, 6 and 24 h after each spiking event. All target PPCPs were identified in the Lobo reservoir water in the range of μg L^-1. The personal care products were detected with 100% frequency in the samples, and in higher concentrations compared to the pharmaceuticals. Degradation products of diclofenac and benzophenone-3 were identified in the water samples. Results of this investigation show that ecological filtration was an effective process (70-99%) to remove 2 μg L^-1 of the selected PPCPs, and demonstrated that the filters were resilient to individual compounds and to their mixtures.

An integrative approach combining passive sampling, bioassays, and effect-directed analysis to assess the impact of wastewater effluent

Wastewater treatment plant (WWTP) effluents are major sources of endocrine-disrupting chemicals (EDCs) and other chemicals of toxicological concern for the aquatic environment. In the present study, we used an integrated strategy combining passive sampling (Chemcatcher®), developmental toxicity, and mechanism-based in vitro and in vivo bioassays to monitor the impacts of a WWTP on a river. In vitro screening revealed the WWTP effluent as a source of estrogen, glucocorticoid, and aryl hydrocarbon (AhR) receptor-mediated activities impacting the downstream river site where significant activities were also measured, albeit to a lesser extent than in the effluent. Effect-directed analysis of the effluent successfully identified the presence of potent estrogens (estrone, 17α-ethinylestradiol, and 17β-estradiol) and glucocorticoids (clobetasol propionate and fluticasone propionate) as the major contributors to the observed in vitro activities, even though other unidentified active chemicals were likely present. The impact of the WWTP was also assessed using zebrafish embryo assays, highlighting its ability to induce estrogenic response through up-regulation of the aromatase promoter-dependent reporter gene in the transgenic (cyp19a1b-green fluorescent protein [GFP]) zebrafish assay and to generate teratogenic effects at nonlethal concentrations in the zebrafish embryo toxicity test. The present study argues for the use of such an integrated approach, combining passive sampling, bioassays, and effect-directed analysis, to comprehensively identify endocrine active compounds and associated hazards of WTTP effluents. Environ Toxicol Chem 2018;37:2079-2088. © 2018 SETAC.

Evaluating porewater polycyclic aromatic hydrocarbon-related toxicity at a contaminated sediment site using a spiked field-sediment approach

Although the complexity of contaminant mixtures in sediments can confound the identification of causative agents of adverse biological response, understanding the contaminant(s) of primary concern at impacted sites is critical to sound environmental management and remediation. In the present study, a stock mixture of 18 polycyclic aromatic hydrocarbon (PAH) compounds was prepared to reflect the variety and relative proportions of PAHs measured in surface sediment samples collected from discrete areas of a historically contaminated industrial estuary. This site-specific PAH stock mixture was spiked into nontoxic in-system and out-of-system field-collected reference sediments in dilution series spanning the range of previously measured total PAH concentrations from the region. Spiked sediments were evaluated in 10-d Leptocheirus plumulosus tests to determine whether toxicity in laboratory-created PAH concentrations was similar to the toxicity found in field-collected samples with equivalent PAH concentrations. The results show that toxicity of contaminated sediments was not explained by PAH exposure, while indicating that toxicity in spiked in-system (fine grain, high total organic carbon [TOC]) and out-of-system (course grain, low TOC) sediments was better explained by porewater PAH concentrations, measured using an antibody-based biosensor that quantified 3- to 5-ring PAHs, than total sediment PAH concentrations. The study demonstrates the application of site-specific spiking experiments to evaluate sediment toxicity at sites with complex mixtures of multiple contaminant classes and the utility of the PAH biosensor for rapid sediment-independent porewater PAH analysis. Environ Toxicol Chem 2018;37:893-902. © 2017 SETAC.

The impact of pesticides on oxidative stress level in human organism and their activity as an endocrine disruptor

Pesticides cause serious environmental and health problems both to humans and animals. The aim of this review is to discuss selected herbicides and fungicides regarding their mode of action and their influence on basic oxidative stress parameters and endocrine disruption properties tested in selected cell cultures in vitro. Because of numerous difficulties which animal studies are subject to, cell cultures are an excellent experimental model reflecting human exposure to different pesticides through all relevant routes. This experimental model can be used to monitor aggregate and cumulative pesticide exposures.

Root-level exposure reveals multiple physiological toxicity of triazine xenobiotics in Arabidopsis thaliana

Herbicides are pollutants of great concern due to environmental ubiquity resulting from extensive use in modern agriculture and persistence in soil and water. Studies at various spatial scales have also highlighted frequent occurrences of major herbicide breakdown products in the environment. Analysis of plant behavior toward such molecules and their metabolites under conditions of transient or persistent soil pollution is important for toxicity evaluation in the context of environmental risk assessment. In order to understand the mechanisms underlying the action of such environmental contaminants, the model plant Arabidopsis thaliana, which has been shown to be highly responsive to pesticides and other xenobiotics, was confronted with varying levels of the widely-used herbicide atrazine and of two of its metabolites, desethylatrazine and hydroxyatrazine, which are both frequently detected in water streams of agriculturally-intensive areas. After 24h of exposure to varying concentrations covering the range of triazine concentrations detected in the environment, root-level contaminations of atrazine, desethylatrazine and hydroxyatrazine were found to affect early growth and development in various dose-dependent and differential manners. Moreover, these differential effects of atrazine, desethylatrazine and hydroxyatrazine pointed to the involvement of distinct mechanisms directly affecting respiration and root development. The consequences of the identification of additional targets, in addition to the canonical photosystem II target, are discussed in relation with the ecotoxicological assessment of environmental xenobiotic contamination.

Evaluation of AhR-agonists and AhR-agonist activity in sediments of Liaohe River protected areas, China

A total of 9 sediment samples of Liaohe River protected areas were collected to evaluate aryl hydrocarbon receptor agonists (AhR-agonists) and AhR-agonist activity via chemical analysis and in vitro H4IIE cell bioassay. Results indicated that bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) ranged from 89.1 to 251.1pg/g dry weight. Concentrations of 16 EPA polycyclic aromatic hydrocarbons (PAHs), 12 dioxin-like polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) ranged from 256.8 to 560.1ng/g, 79.2 to 416.2pg/g, and 199.6 to 538.4pg/g, respectively. According to potency balance analysis, TEQ_chems based on PAHs, PCBs, and PCDD/Fs could contribute 16.56% to 26.11% of Bio-TEQs. This could be explained by the potential existence of unidentified AhR-agonists and the potential non-additive interactions among AhR-agonists in sediment extracts. Through the different contributions to Bio-TEQs, this study confirms that PCDD/Fs were the main pollutants that induced significantly AhR-agonist activity in sediments of Liaohe River protected areas.

Evaluation of an extraction method for a mixture of endocrine disrupters in sediment using chemical and in vitro biological analyses

Aquatic sediments are contaminated by a wide diversity of organic pollutants such as endocrine-disrupting chemicals (EDCs) which encompass a broad range of chemical classes having natural and anthropogenic origins. The use of in vitro bioassays is now widely accepted as an alternative method for their detection in complex samples. However, based on the diversity of EDC chemical properties, their common extraction is difficult and comprehensive validation of extraction methods for a bioanalysis purpose is still weakly documented. In this study, we compared the performance of several organic solvents, i.e., acetone, methanol, dichloromethane, heptane, dichloromethane/acetone (50:50, v/v), dichloromethane/methanol (50:50, v/v), heptane/acetone (50:50, v/v), and heptane/methanol (50:50, v/v), to extract a diversity of active chemicals from a spiked sediment matrix using pressurized liquid extraction. For this purpose, we defined a mixture of 12 EDCs with a wide range of polarity (2 < log Kow < 8) (i.e., estrone, 17β-estradiol, bisphenol A, o,p'DDT, 4-tert-octylphenol, fenofibrate, triphenyl phosphate, clotrimazole, PCB-126, 2,3,7,8 TCDD, benzo[k]fluoranthene, and dibenzo[a,h]anthracene). Working concentrations of each individual compound in the mixture were determined as equipotent concentrations on the basis of the concentration-addition (CA) model applied to in vitro estrogenic, dioxin-like, and pregnane X receptor (PXR)-like activities. Extraction efficiencies based on both chemical and biological analyses were assessed in triplicate in artificial blank sediment spiked with this mixture and in natural sediment contaminated by native EDCs. In both spiked and natural sediment, MeOH/DCM yields the best recovery while heptane was the least efficient solvent. Our study provided the validation of a sediment extraction methodology for EDC bioanalysis purposes, which can be used for comprehensive environmental contamination characterization.

Dose-response behavior of the bacterium Vibrio fischeri exposed to pharmaceuticals and personal care products

The presence of pharmaceuticals and personal care products (PPCPs) in the environment has become a real and widespread concern in recent years. Therefore, the primary goal of this study was to investigate 20 common and widely used PPCPs to assess their individual and combined effect on an important species in one trophic level, i.e., bacteria. The ecotoxicological effects of PPCPs at two different concentration ranges were determined in the bacterium Vibrio fischeri using Microtox(®) and were statistically analyzed using three models in the GraphPad Prism 6 program for Windows, v.6.03. A four-parameter model best fit the majority of the compounds. The half maximal effective concentration (EC50) of each PPCP was estimated using the best-fitting model and was compared with the results from a recent study. Comparative analysis indicated that most compounds showed the same level of toxicity. Moreover, the stimulatory effects of PPCPs at environmental concentrations (low doses) were assessed. These results indicated that certain compounds have traditional inverted U- or J-shaped dose-response curves, and 55% of them presented a stimulatory effect below the zero effect-concentration point. Effective concentrations of 0 (EC0), 5 (EC5) and 50% (EC50) were calculated for each PPCP as the ecotoxicological points. All compounds that presented narcosis as a mode of toxic action at high doses also exhibited stimulation at low concentrations. The maximum stimulatory effect of a mixture was higher than the highest stimulatory effect of each individually tested compound. Moreover, when the exposure time was increased, the hormetic effect decreased. Hormesis is being increasingly included in dose-response studies because this may have a harmful, beneficial or indifferent effect in an environment. Despite the results obtained in this research, further investigations need to be conducted to elucidate the behavior of PPCPs in aquatic environments.

Genome-Wide Transcriptional Profiling and Metabolic Analysis Uncover Multiple Molecular Responses of the Grass Species Lolium perenne Under Low-Intensity Xenobiotic Stress

Lolium perenne, which is a major component of pastures, lawns, and grass strips, can be exposed to xenobiotic stresses due to diffuse and residual contaminations of soil. L. perenne was recently shown to undergo metabolic adjustments in response to sub-toxic levels of xenobiotics. To gain insight in such chemical stress responses, a de novo transcriptome analysis was carried out on leaves from plants subjected at the root level to low levels of xenobiotics, glyphosate, tebuconazole, and a combination of the two, leading to no adverse physiological effect. Chemical treatments influenced significantly the relative proportions of functional categories and of transcripts related to carbohydrate processes, to signaling, to protein-kinase cascades, such as Serine/Threonine-protein kinases, to transcriptional regulations, to responses to abiotic or biotic stimuli and to responses to phytohormones. Transcriptomics-based expressions of genes encoding different types of SNF1 (sucrose non-fermenting 1)-related kinases involved in sugar and stress signaling or encoding key metabolic enzymes were in line with specific qRT-PCR analysis or with the important metabolic and regulatory changes revealed by metabolomic analysis. The effects of pesticide treatments on metabolites and gene expression strongly suggest that pesticides at low levels, as single molecule or as mixture, affect cell signaling and functioning even in the absence of major physiological impact. This global analysis of L. perenne therefore highlighted the interactions between molecular regulation of responses to xenobiotics, and also carbohydrate dynamics, energy dysfunction, phytohormones and calcium signaling.

The mussel caging approach in assessing biological effects of wastewater treatment plant discharges in the Gulf of Finland (Baltic Sea)

Biological effects of wastewater treatment plant (WWTP) effluents were investigated in Baltic mussels (Mytilus trossulus) caged for one month 800m and 1100m from the WWTP discharge site and at a reference site 4km away. Significant antioxidant, genotoxic and lysosomal responses were observed close to the point of the WWTP discharge. Passive samplers (POCIS) attached to the cages indicated markedly higher water concentrations of various pharmaceuticals at the two most impacted sites. Modeling the dispersal of a hypothetical passive tracer compound from the WWTP discharge site revealed differing frequencies and timing of the exposure periods at different caging sites. The study demonstrated for the first time the effectiveness of the mussel caging approach in combination with passive samplers and the application of passive tracer modeling to examine the true exposure patterns at point source sites such as WWTP pipe discharges in the Baltic Sea.

Occurrence of pharmaceutical compounds and pesticides in aquatic systems

This paper deals with the detection and quantification of APIs and other priority substances in the Arade River estuary (Portugal) providing the usefulness of Polar Organic Compound Integrative Samplers (POCIS). Thirteen APIs were detected whose variation was site and time dependent. Caffeine was at the highest concentration (804±209 ng/L) followed by theophylline (184±44 ng/L). Other APIs were analgesic, anticonvulsant, non-steroidal anti-inflammatory drugs, anti-lipidemic, anxiolytic and antidepressants. Twenty pesticides comprising atrazine, diuron, isoproturon, terbutryn and simazine included in the Water Framework Directive priority list were also site and time dependent. Carbendazim occurred at the highest concentration (45±18 ng/L at site 1) but atrazine, diuron, isoproturon and simazine levels were below the Environmental Quality Standards. Although the summer impact was unclear, the results highlighted POCIS suitability for profiling these contaminants. This is to our knowledge the first study concerning APIs and pesticides in this area.

Metabolic profiling of Lolium perenne shows functional integration of metabolic responses to diverse subtoxic conditions of chemical stress

Plant communities are confronted with a great variety of environmental chemical stresses. Characterization of chemical stress in higher plants has often been focused on single or closely related stressors under acute exposure, or restricted to a selective number of molecular targets. In order to understand plant functioning under chemical stress conditions close to environmental pollution conditions, the C3 grass Lolium perenne was subjected to a panel of different chemical stressors (pesticide, pesticide degradation compound, polycyclic aromatic hydrocarbon, and heavy metal) under conditions of seed-level or root-level subtoxic exposure. Physiological and metabolic profiling analysis on roots and shoots revealed that all of these subtoxic chemical stresses resulted in discrete physiological perturbations and complex metabolic shifts. These metabolic shifts involved stressor-specific effects, indicating multilevel mechanisms of action, such as the effects of glyphosate and its degradation product aminomethylphosphonic acid on quinate levels. They also involved major generic effects that linked all of the subtoxic chemical stresses with major modifications of nitrogen metabolism, especially affecting asparagine, and of photorespiration, especially affecting alanine and glycerate. Stress-related physiological effects and metabolic adjustments were shown to be integrated through a complex network of metabolic correlations converging on Asn, Leu, Ser, and glucose-6-phosphate, which could potentially be modulated by differential dynamics and interconversion of soluble sugars (sucrose, trehalose, fructose, and glucose). Underlying metabolic, regulatory, and signalling mechanisms linking these subtoxic chemical stresses with a generic impact on nitrogen metabolism and photorespiration are discussed in relation to carbohydrate and low-energy sensing.

Identification of thyroid-receptor antagonists in water from the Guanting Reservoir, Beijing, China

Thyroid hormone (TH) has long been known to be essential for normal brain development in both humans and animals, and increasing evidence suggests that environmental components may disrupt TH signaling. In the present study, two-hybrid yeast bioassay and chemical analysis were used to evaluate and identify thyroid-receptor (TR) disruptors in water from the Guanting Reservoir, Beijing, China. Modified yeast bioassay showed that the water samples could affect TH signaling. The bioassay-derived amiodarone hydrochloride equivalents ranged from 33.8 ± 3.3 to 308.5 ± 31.8 µg/L. Solid-phase extraction was used to separate the organic extracts, which were subjected to bioassay and chemical analysis. The organic extracts significantly antagonized the TR, which accounted for >86.0 % of the total effects. Thus, organic extracts may play a major role in the TR-disruption activity of the water. Phenols, organochlorine pesticides, and phthalate esters were detected in the organic extracts. Chemical analysis and toxic-equivalent calculation showed that a major cause of the TR antagonism of the water was dibutyl phthalate (80.1 to 122.7 %).

UV light and urban pollution: bad cocktail for mosquitoes?

Mosquito breeding sites consist of water pools, which can either be large open areas or highly covered ponds with vegetation, thus with different light exposures combined with the presence in water of xenobiotics including polycyclic aromatic hydrocarbons (PAHs) generated by urban pollution. UV light and PAHs are abiotic factors known to both affect the mosquito insecticide resistance status. Nonetheless, their potential combined effects on the mosquito physiology have never been investigated. The present article aims at describing the effects of UV exposure alongside water contamination with two major PAH pollutants (fluoranthene and benzo[a]pyrene) on a laboratory population of the yellow fever mosquito Aedes aegypti. To evaluate the effects of PAH exposure and low energetic UV (UV-A) irradiation on mosquitoes, different parameters were measured including: (1) The PAH localization and its impact on cell mortality by fluorescent microscopy; (2) The detoxification capacities (cytochrome P450, glutathione-S-transferase, esterase); (3) The responses to oxidative stress (Reactive Oxygen Species-ROS) and (4) The tolerance of mosquito larvae to a bioinsecticide (Bacillus thuringiensis subsp. israelensis-Bti) and to five chemical insecticides (DDT, imidacloprid, permethrin, propoxur and temephos). Contrasting effects regarding mosquito cell mortality, detoxification and oxidative stress were observed as being dependent on the pollutant considered, despite the fact that the two PAHs belong to the same family. Moreover, UV is able to modify pollutant effects on mosquitoes, including tolerance to three insecticides (imidacloprid, propoxur and temephos), cell damage and response to oxidative stress. Taken together, our results suggest that UV and pollution, individually or in combination, are abiotic parameters that can affect the physiology and insecticide tolerance of mosquitoes; but the complexity of their direct effect and of their interaction will require further investigation to know in which condition they can affect the efficacy of insecticide-based vector control strategies in the field.

Ranking of concern, based on environmental indexes, for pharmaceutical and personal care products: an application to the Spanish case

A wide range of Pharmaceuticals and Personal Care Products (PPCPs) are present in the environment, and many of their adverse effects are unknown. The emergence of new compounds or changes in regulations have led to dynamical studies of occurrence, impact and treatment, which consider geographical areas and trends in consumption and innovation in the pharmaceutical industry. A Quantitative study of Structure-Activity Relationship ((Q)SAR) was performed to assess the possible adverse effects of ninety six PPCPs and metabolites with negligible experimental data and establish a ranking of concern, which was supported by the EPA EPI Suite™ interface. The environmental and toxicological indexes, the persistence (P), the bioaccumulation (B), the toxicity (T) (extensive) and the occurrence in Spanish aquatic environments (O) (intensive) were evaluated. The most hazardous characteristics in the largest number of compounds were generated by the P index, followed by the T and B indexes. A high number of metabolites has a concern score equal to or greater than their parent compounds. Three PBT and OPBT rankings of concern were proposed using the total and partial ranking method (supported by a Hasse diagram) by the Decision Analysis by Ranking Techniques (DART) tool, which was recently recommended by the European Commission. An analysis of the sensibility of the relative weights of these indexes has been conducted. Hormones, antidepressants (and their metabolites), blood lipid regulators and all of the personal care products considered in this study were at the highest levels of risk according to the PBT and OPBT total rankings. Furthermore, when the OPBT partial ranking was performed, X-ray contrast media, H2 blockers and some antibiotics were included at the highest level of concern. It is important to improve and incorporate useful indexes for the predicted environmental impact of PPCPs and metabolites and thus focus experimental analysis on the compounds that require urgent attention.

Low environmentally relevant levels of bioactive xenobiotics and associated degradation products cause cryptic perturbations of metabolism and molecular stress responses in Arabidopsis thaliana

Anthropic changes and chemical pollution confront wild plant communities with xenobiotic combinations of bioactive molecules, degradation products, and adjuvants that constitute chemical challenges potentially affecting plant growth and fitness. Such complex challenges involving residual contamination and mixtures of pollutants are difficult to assess. The model plant Arabidopsis thaliana was confronted by combinations consisting of the herbicide glyphosate, the fungicide tebuconazole, the glyphosate degradation product aminomethylphosphonic acid (AMPA), and the atrazine degradation product hydroxyatrazine, which had been detected and quantified in soils of field margins in an agriculturally intensive region. Integrative analysis of physiological, metabolic, and gene expression responses was carried out in dose-response experiments and in comparative experiments of varying pesticide combinations. Field margin contamination levels had significant effects on plant growth and metabolism despite low levels of individual components and the presence of pesticide degradation products. Biochemical and molecular analysis demonstrated that these less toxic degradation products, AMPA and hydroxyatrazine, by themselves elicited significant plant responses, thus indicating underlying mechanisms of perception and transduction into metabolic and gene expression changes. These mechanisms may explain observed interactions, whether positive or negative, between the effects of pesticide products (AMPA and hydroxyatrazine) and the effects of bioactive xenobiotics (glyphosate and tebuconazole). Finally, the metabolic and molecular perturbations induced by low levels of xenobiotics and associated degradation products were shown to affect processes (carbon balance, hormone balance, antioxidant defence, and detoxification) that are likely to determine environmental stress sensitivity.

Distribution of steroid- and dioxin-like activities between sediments, POCIS and SPMD in a French river subject to mixed pressures

The contamination of aquatic systems by endocrine disrupting chemicals (EDCs) is now a widely established fact. Nevertheless, there is still a scarcity of knowledge concerning the source, transport, fate and bioavailability of such active compounds. In the present study we assessed the distribution of estrogenic, (anti-)androgenic, pregnane X receptor-like (PXR) and dioxin-like activities between sediment and water compartments using a polar organic compound integrative sampler (POCIS) and a semi-permeable membrane device (SPMD) passive sampler in a river where sediment has been previously described as highly and multi-contaminated. We first confirmed the contamination pattern of this river sediment between 2004, 2009 and 2010 samples, suggesting that this river is subject to a constant high contamination level. However, we showed a different distribution pattern of these activities between compartments: estrogenic activity was mainly detected in POCIS extracts and to a lesser extent in sediment and SPMD extracts; anti-androgenic activities were mainly detected in SPMD and sediment extracts while no activity was detected in POCIS extracts; PXR-like activity was detected in all three investigated compartments, with POCIS > SPMD > sediment; dioxin-like activity was mainly found in the sediment and the SPMD extracts. Overall, partitioning of the biological activities was in accordance with physicochemical properties (e.g., log K ow) of typical known active chemicals in each bioassay. Furthermore, in order to establish whether the chemicals involved in these activities were similar between the compartments, we fractionated sediment, POCIS and SPMD extracts using a multi-step fractionation procedure. This highlighted differences in the nature of active chemicals between compartments. Altogether, our results support the need to consider different compartments in order to enhance exposure assessment.

Effect-directed analysis of endocrine-disrupting compounds in multi-contaminated sediment: identification of novel ligands of estrogen and pregnane X receptors

Effect-directed analysis (EDA)-based strategies have been increasingly used in order to identify the causative link between adverse (eco-)toxic effects and chemical contaminants. In this study, we report the development and use of an EDA approach to identify endocrine-disrupting chemicals (EDCs) in a multi-contaminated river sediment. The battery of in vitro reporter cell-based bioassays, measuring estrogenic, (anti)androgenic, dioxin-like, and pregnane X receptor (PXR)-like activities, revealed multi-contamination profiles. To isolate active compounds of a wide polarity range, we established a multi-step fractionation procedure combining: (1) a primary fractionation step using normal phase-based solid-phase extraction (SPE), validated with a mixture of 12 non-polar to polar standard EDCs; (2) a secondary fractionation using reversed-phase-based high-performance liquid chromatography (RP-HPLC) calibrated with 33 standard EDCs; and (3) a purification step using a recombinant estrogen receptor (ER) affinity column. In vitro SPE and HPLC profiles revealed that ER and PXR activities were mainly due to polar to mid-polar compounds, while dioxin-like and anti-androgenic activities were in the less polar fractions. The overall procedure allowed final isolation and identification of new environmental PXR (e.g., di-iso-octylphthalate) and ER (e.g., 2,4-di-tert-butylphenol and 2,6-di-tert-butyl-α-methoxy-p-cresol) ligands by using gas chromatography coupled with mass spectrometry with full-scan mode acquisition in mid-polar fractions. In vitro biological activity of these chemicals was further confirmed using commercial standards, with di-iso-octylphthalate identified for the first time as a potent hPXR environmental agonist.

AhR-mediated potency of sediments and soils in estuarine and coastal areas of the Yellow Sea region: a comparison between Korea and China

Extracts of sediments (n = 45) and soils (n = 37) collected from the coast of the Yellow Sea, in Korea and China, were screened for their ability to induce dioxin-like gene expression in vitro using the H4IIE-luc, transactivation bioassay. Significant dioxin-like potency was observed except for a few soils from Korea. Concentrations of TCDD-EQ (2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents) in sediments were comparable between Korea and China, but concentrations of TCDD-EQ in soil were 2-fold greater from Korea. Mass balance analysis indicated that concentrations of TCDD-EQ were to some degree chemical- and/or matrix-dependent, but were much more site-specific. For example, the proportion of the TCDD-EQ that could be identified varied among locations, which suggests different sources. Unidentified AhR-active compounds represented a greater proportion of the TCDD-EQ in samples from Korea, which suggests that sources in Korea were more complex than those in China. Potential sources of TCDD-EQ were investigated by considering land-uses and local activities.

Effects of anticholinesterase drugs on biomarkers and behavior of pumpkinseed, Lepomis gibbosus (Linnaeus, 1758)

The presence of pharmaceutical residues in the aquatic environment has recently received great attention, as potential adverse effects may arise from their presence. Inhibition of cholinesterases (ChE) has been widely used as an environmental biomarker of exposure to organophosphates (OP) and carbamate (CB) pesticides. However, other widespread anthropogenic contaminants - including pharmaceutical drugs - can exert toxic effects through ChE inhibition. Studies with aquatic species have shown that inhibition of ChE is associated with behavioral changes. Bearing this in mind, this work aimed to study the effects on individual behavior and acetylcholinesterase (AChE) activity of selected tissues of Lepomis gibbosus, after exposure to the anticholinesterasic drugs neostigmine and pyridostigmine. Results revealed that neostigmine significantly decreased the activity of AChE in the head (LOEC = 100 mg L(-1)), but not in dorsal muscle. On the other hand, pyridostigmine significantly decreased the activity of AChE in both the head (LOEC = 0.001 mg L(-1)) and dorsal muscle homogenates (LOEC = 100 mg L(-1)). The impairment of this enzymatic form was attained at ecologically relevant concentrations (in the case of pyridostigmine, for head AChE), which is an interesting finding, specially considering that these toxic effects occurred for a pharmaceutical compound. Contrarily, there were no significant differences in the behavior of L. gibbosus in any parameter, for neither drug. These results suggest that the behavioral parameters analyzed (scototaxis and lethargy) in L. gibbosus could not be regarded as suitable markers to assess the effects of drugs such as neostigmine and pyridostigmine. In contrast, the pattern of response elicited by cholinesterasic inhibition showed the usefulness of this toxicological parameter for the assessment of pharmaceuticals in the environment, namely anticholinesterasics.