Microplastic pollution and its environmental consequences have been a research topic for decades. Alongside sewage sludge and compost, mulch films are one of the most important sources of organic matter in agricultural soils. As microplastics accumulate in these environments, they increasingly interact with other agrochemical contaminants, such as pesticides. The consequences of the combined presence of mulch film microplastic and pesticides, especially on bioavailability and toxicity, still need to be understood. We investigated the interaction of pesticides with polyethylene mulch films by choosing the neonicotinoid Thiacloprid and the fungicide Tebuconazole in their commercial formulations as plant protection products, serving as representative hydrophobic and hydrophilic substances. The impact of PE microplastic (150 mg/kg) on both pesticides' extractability and earthworm mortality was determined. The hypothesis is that microplastics reduce pesticide bioavailability in soil. Hence, reduced earthworm toxicity might be observed. Acute toxicity testing with Eisenia fetida showed a slight decrease in toxicity while MPP was present, shifting the LC50 from 110.3 to 120.6 mg/kg (Tebuconazole) and 20.3-22.6 mg/kg (Thiacloprid). The chemical analysis after two-time extraction of test soil with CaCl2 and then solvents confirmed the reduced availability of pesticide in the presence of MPP. Our research shows that microplastic at application-relevant concentrations can retain pesticides and reduce pesticide toxicity. These findings impact pesticide efficiency in soils that accumulate microplastic, potentially requiring the adaptation of agricultural practices. This study underscores the need for further research and mitigation strategies as our understanding of the interactions between pesticides and microplastics in soil evolves.

Crude oil can affect the normal eye development and swimming behavior of fish embryos. In this study 0-4 hours post fertilization (hpf) zebrafish ( Danio rerio ) embryos were exposed to low, sublethal concentrations of water-accommodated fractions (WAF) of a naphthenic North Sea crude oil alone and in combination with a third-generation chemical dispersant. Effects on eye development and function at the transcript, histological, morphological, and behavioral level were assessed relative to untreated control specimen at 119 hpf. Exposed embryos swam significantly less during the dark phases of the light/dark transition test. Eye size of zebrafish embryos was significantly smaller in groups exposed to crude oil WAFs. Zebrafish retina histology revealed that, among other structural alterations, the outer nuclear layer, containing photoreceptor cells relevant for normal visual functioning, was significantly thinner in exposed embryos. Transcriptome analysis revealed that several genes involved in eye development and function (opsins and crystallins) were dysregulated upon oil exposure. The molecular effects on gene expression and eye histology results form a novel line of evidence that explains the observed effects of crude oil on the swimming activity of exposed fish embryos. The present study is in line with recent findings highlighting the importance of ocular toxicity in developing embryos exposed to petroleum samples at environmentally relevant and non-lethal concentrations without visible malformations. The study suggests that oculotoxicity should be considered as a major toxicity pathway alongside to the well-established cardiotoxicity.### Competing Interest StatementThe authors have declared no competing interest.

Ecotoxicological assays have traditionally focused on the effects of chemicals at the individual level by exploiting mortality and reproduction as endpoints. Although these two parameters are ecologically relevant, they rarely provide information regarding the elemental toxic mechanisms. Obviously, the number of xenobiotics used has been rapidly increased. Thus, any established measurement that shortens the actual outcome and, simultaneously provides information about toxic mechanisms is desirable. This research focused on the study of oxidative stress response as a biomarker in the eukaryotic model organism, Saccharomyces cerevisiae. For this, yeast cells were exposed to a set of selected environmentally relevant chemicals via different approaches, including cellular diagnostics, gene expression analysis and chemo-genetic screening. The results demonstrated that at the cellular level, model organisms reacted to different chemicals in distinct manner. For each xenobiotic, the correlation between toxic response of molecular and cellular levels are presented. Namely, the expression of target genes after chemical exposure affected the cellular alteration as evidenced by an elevated level of superoxide dismutase and a reduced amount of glutathione. Furthermore, the results derived from chemo-genetic screening, in which mutants lacking of gene of interest were employed, exhibited more susceptibility to test chemicals in comparison to the wildtype. The response of oxidative stress upon chemical exposure in budding yeast from this study is potentially useful for an establishment of a proper bio-test system which can eventually be linked to adverse effects at an individual level in higher eukaryotes.

Chemical pollution resulting from pesticide usage has been a continuous issue since the 1960s, despite comprehensive European Union legislation designed to safeguard human health and the environment from the adverse effects of pesticides. While regulatory risk assessments primarily focus on the active ingredients, recent research indicates ecotoxicological impacts of commercial preparations on non-target organisms, particularly within the soil ecosystem where key species such as earthworms play a vital role in maintaining soil quality and fertility. Therefore, the aim of this study was the assessment of the long-term effects of the following respective commercial preparations: the insecticides Sumialfa (esfenvalerate) and Calypso (thiacloprid), as well as the herbicides Frontier (dimethenamid-p) and Filon (prosulfocarb) on the earthworm Eisenia andrei in standardized soil during long-term exposures of 7, 14, and 28 days. To study the possible effects on different levels of biological organization, enzymatic biomarkers: acetylcholinesterase (AChE), carboxylesterase (CES) glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx); non-enzymatic biomarkers: multixenobiotic resistance activity (MXR), levels of glutathione (GSH), and reactive oxygen species (ROS) as well as reproductive success were investigated. While Calypso appeared to be the least toxic substance, all pesticides showed significant effect on multiobiomarker response in E. fetida. That being said, the response of MXR activity was significantly altered by all tested pesticides indicating MXR being the most sensitive endpoint of the present research. Recovery of MXR was observed after 28 days, however, only in case of exposure to Filon, while the recovery of CAT activity was recorded after 28 days as well, subsequent to Sumialfa exposure. Reproductive success was negatively impacted regarding the Frontier and Sumialfa exposure at the highest concentration (100 mg/kg) reflected in reduced number of cocoons, while only the exposure to Frontier (100 mg/kg) reduced the number of juveniles. Based on the results, it is important to include commercial pesticide formulations in pesticide risk assessments. The toxicity classifications of the studied pesticides suggest the potential detrimental consequences to the key soil species in terrestrial ecosystems at various concentrations. Future studies should include other soil species as well as investigation of higher levels of biological organization, i.e., behavioral endpoints, to determine the potential risks to terrestrial ecosystems.

Earthworms are key organisms of the soil ecosystem and bioindicators for soil quality. While pesticides are used for the improvement of crop yields, they also present a burden for soil organisms. To understand the complex effects of pesticides on soil organisms, it is important to test these effects in soil exposures to include influences of the soil matrix on the toxicity. Therefore, the aim of this study was the assessment of the effects pesticides on earthworm Eisenia andrei. In an initial screening, active ingredients and commercial preparations were tested for comparison. Since the commercial preparations showed a higher toxicity, all further investigations (biomarkers, multixenobiotic resistance (MXR) activity, and avoidance behavior) were performed using the commercial pesticide formulations only: Sumialfa (esfenvalerate), Calypso (thiacloprid), Frontier (dimethenamid-p), and Filon (prosulfocarb). Significant differences in avoidance behavior were observed for Filon and Frontier. All pesticides inhibited the MXR activity and affected oxidative stress-related markers. Frontier was the only pesticide that did not affect enzymatic biomarkers related to neurotransmission. The results show the potential hazards associated with the usage of the tested pesticides and the importance of evaluating the effects of commercial pesticide preparations for a more realistic insight into the adverse effects on the environment.

The pollution state in the German Bight was investigated by determination of pollutant concentrations of sediment samples using equilibrium passive sampling. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAH) were determined in the pore water of North Sea sediment. The freely dissolved pore water concentration (Cfree) was measured applying Solid Phase Microextraction (SPME) by using PDMS-coated glass fibers. The obtained results show that the North Sea contamination level with the investigated pollutants is relatively low. However, the stations close to the sediment-dumping site were higher contaminated. A macrofauna analysis showed that bioturbation activities were mostly present in the upper sediment layers, but a direct bioturbation influence on the sediment concentration distribution could not be shown. Overall, the contamination load was below baseline toxicity, but considering that several other priority pollutants will also make a contribution to the baseline toxicity, it can be counted as relatively high.

The assessment of the exposure of aquatic wildlife to complex environmental mixtures of chemicals originating from both point and diffuse sources and evaluating the potential impact thereof constitutes a significant step towards mitigating toxic pressure and the improvement of ecological status. In the current proof-of-concept study, we demonstrate the potential of a novel Aggregated Biomarker Response (ABR) approach involving a comprehensive set of biomarkers to identify complex exposure and impacts on wild brown trout (Salmo trutta fario). Our scenario used a small lowland river in Germany (Holtemme river in the Elbe river catchment) impacted by two wastewater treatment plants (WWTP) and diffuse agricultural runoff as a case study. The trout were collected along a pollution gradient (characterised in a parallel study) in the river. Compared to fish from the reference site upstream of the first WWTP, the trout collected downstream of the WWTPs showed a significant increase in micronucleus formation, phase I and II enzyme activities, and oxidative stress parameters in agreement with increasing exposure to various chemicals. By integrating single biomarker responses into an aggregated biomarker response, the two WWTPs' contribution to the observed toxicity could be clearly differentiated. The ABR results were supported by chemical analyses and whole transcriptome data, which revealed alterations of steroid biosynthesis and associated pathways, including an anti-androgenic effect, as some of the key drivers of the observed toxicity. Overall, this combined approach of in situ biomarker responses complemented with molecular pathway analysis allowed for a comprehensive ecotoxicological assessment of fish along the river. This study provides evidence for specific hazard potentials caused by mixtures of agricultural and WWTP derived chemicals at sublethal concentrations. Using aggregated biomarker responses combined with chemical analyses enabled an evidence-based ranking of sites with different degrees of pollution according to toxic stress and observed effects.

Green toxicology is a novel approach increasingly applied for the development of materials and chemicals that are more benign to the environment and human health than their conventional counterparts. It includes predictive eco-toxicological assessments of chemicals during the early developmental process to exclude adverse effects. In the present study, two guanidine zinc catalysts for the ring-opening polymerization of lactide were investigated using eco-toxicological tools. Namely, the fish embryo toxicity assay for teratogenic effects, the ER (α) CALUX assay for endocrine activity and the Ames fluctuation assay for mutagenic potential were applied. Both complexes showed no endocrine activity, mutagenicity or acute aquatic toxicity, however a delayed hatch could be observed, therefore suggesting potential effects on a molecular level. This proof-of-concept study aims to assess the toxicity of guanidine zinc catalysts and is a first step towards the incorporation of toxicological assessments into chemical developmental processes to achieve a sustainable and safe production of catalysts.

The increasing concern over bisphenol A (BPA) has directed much attention toward bisphenol F (BPF) and bisphenol S (BPS) as BPA alternatives for the development of "BPA-free" products. Consequently, BPS and BPF were frequently detected in surface water, sediment, sewage effluent, indoor dust, and even in food and biological fluids in humans. Thus, environmental researches start to focus on the potential environmental risks of BPA alternatives. While the estrogenically active metabolites and the specific estrogenically active structure are still unknown. In this study, the MTT assay on acute cytotoxicity and the recombinant transactivation assay were carried out to determine whether BPF and BPS are suitable alternatives to BPA. Our results show that the cytotoxic and estrogenic activities of BPS and BPF are lower than those of BPA. However, after the addition of a rat liver homogenate to simulate mammal metabolism, BPF exhibited higher estrogenic activity than BPA. To identify the chemical structures and estrogen receptor binding affinities of active estrogenic metabolites, LC-MS, MetaPrint2D(-React), and VirtualToxLab were integrated. The observed results indicated that the para-hydroxylated BPF and BPF-OCH3 might have strong ER binding affinities. These results demonstrate that metabolization is important to consider upon investigating endocrine disruption of chemicals getting into contact with humans, such as in dental sealing or food packaging. Alternatives to potentially hazardous substances should be thoroughly tested prior to use.

A possible way to alleviate the public skepticism toward regulatory science is to increase transparency by making all data and value judgments used in regulatory decision making accessible for public interpretation, ideally early on in the process, and following the concepts of Open Science. This paper discusses the opportunities and challenges in strengthening Open Science initiatives in regulatory environmental risk assessment (ERA). In this discussion paper, we argue that the benefits associated with Open Science in regulatory ERA far outweigh its perceived risks. All stakeholders involved in regulatory ERA (e.g., governmental regulatory authorities, private sector, academia, and nongovernmental organizations), as well as professional organizations like the Society of Environmental Toxicology and Chemistry, can play a key role in supporting the Open Science initiative, by promoting the use of recommended reporting criteria for reliability and relevance of data and tools used in ERA, and by developing a communication strategy for both professionals and nonprofessionals to transparently explain the socioeconomic value judgments and scientific principles underlying regulatory ERA. Integr Environ Assess Manag 2021;17:1229–1242. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

A key aspect of the transformation of the economic sector towards a sustainable bioeconomy is the development of environmentally friendly alternatives for hitherto used chemicals, which have negative impacts on environmental health. However, the implementation of an ecotoxicological hazard assessment at early steps of product development to elaborate the most promising candidates of lowest harm is scarce in industry practice. The present article introduces the interdisciplinary proof-of-concept project GreenToxiConomy, which shows the successful application of a Green Toxicology strategy for biosurfactants and a novel microgel-based pesticide release system. Both groups are promising candidates for industrial and agricultural applications and the ecotoxicological characterization is yet missing important information. An iterative substance- and application-oriented bioassay battery for acute and mechanism-specific toxicity within aquatic and terrestrial model species is introduced for both potentially hazardous materials getting into contact with humans and ending up in the environment. By applying in silico QSAR-based models on genotoxicity, endocrine disruption, skin sensitization and acute toxicity to algae, daphnids and fish, individual biosurfactants resulted in deviating toxicity, suggesting a pre-ranking of the compounds. Experimental toxicity assessment will further complement the predicted toxicity to elaborate the most promising candidates in an efficient pre-screening of new substances.

Around the world, many ambitious environmental conventions and regulations have been implemented over recent decades. Despite this, the environment is still deteriorating. An increase in the volume and diversity of chemicals is one of the main drivers of this deterioration, of which biodiversity loss is a telling indicator. In response to this situation, in October 2020, a chemicals strategy for sustainability (CSS) was published in the EU. The CSS is the first regional framework aiming to address chemical pollution in a holistic manner. The CSS covers the complete lifecycle of a chemical, including the design of better substances and remediation options, to remove chemicals from the environment. The strategy contains terms, such as a “toxic‐free environment,” for which no clear definition exists, potentially hampering the implementation of the CSS. In this paper, a definition for a “toxic‐free environment” is proposed on the basis of a survey and a discussion held at the 2020 SETAC Europe Annual Meeting. In addition, key issues that are absent from the CSS but are considered to be key for the realization of a toxic‐free environment are identified. To achieve the policy goals, it is recommended to align the definition of risk across the different chemical legislations, to establish a platform for open data and data sharing, and to increase the utility and use of novel scientific findings in policymaking, through the development of a strong science to regulation feedback mechanism and vice versa. The paper concludes that environmental scientists have the tools to address the key challenges presented in the CSS. However, an extra step is needed by both policymakers and scientists to develop methods, processes and tools, to increase the robustness and transparency of deliberation processes, and the utility of science. Integr Environ Assess Manag 2021;17:1105–1113. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Environmental risk perception of stakeholders for various human activities is germane to the sustainable development of a society. In urban Africa, rising population rates pose environmental challenges for the management of aquatic resources. Examples of two metropolitan cities in urban Africa are Lagos and Ogun states, Nigeria, with their teeming populations. The proximity of the Lagos lagoon and Ogun River to human settlements predisposes their use as sinks for disposal of wastewatersWastewaters \b from potentially polluting activities such as sawmills and livestock processing (abattoirs). This chapter evaluates the environmental risk perception of specific stakeholders in the states whose activities result in potential adverse impact on aquatic ecosystems and associated ecosystem services. Copies of a structured questionnaire were administered to stakeholders at selected anthropogenic sites, i.e. Okobaba Sawmills and Kara Cow Market, in Lagos and Ogun states respectively. At the Okobaba sawmills adjoining the Lagos lagoon, respondents stated that sawdust is the major (84%) waste generated, most (90%) of which is burnt. Over half (51–90%) of the respondents noted that air quality, water quality and aquatic animals are adversely impacted by the sawmill activities. At Kara Cow Market, which adjoins Ogun River, respondents reported that they utilise the river for domestic activities, such as source of drinking water and for washing of cows. Most respondents (70–82%) acknowledged that the river is polluted, wastes are deliberately disposed into the river and wastewater from the abattoir is never treated. It is suggested that stakeholder environmental education, advocacy, risk communication, as well as demand for, and implementation of, evidence-based policies for the management of these ecosystems are crucial steps to be taken in addressing the situation. Further, the planning of human settlements near aquatic ecosystems should be considered alongside the sustainability of aquatic resources and ecosystem services in urban Africa, given the need to support life below water (UN SDG 14).

Genotoxicity assessment is of high relevance for crude and refined petroleum products, since oil compounds are known to cause DNA damage with severe consequences for aquatic biota as demonstrated in long-term monitoring studies. This study aimed at the optimization and evaluation of small-scale higher-throughput assays (Ames fluctuation, micronucleus, Nrf2-CALUX®) covering different mechanistic endpoints as first screening tools for genotoxicity assessment of oils. Cells were exposed to native and chemically dispersed water-accommodated fractions (WAFs) of three oil types varying in their processing degree. Independent of an exogenous metabolic activation system, WAF compounds induced neither base exchange nor frame shift mutations in bacterial strains. However, significantly increased chromosomal aberrations in zebrafish liver (ZF-L) cells were observed. Oxidative stress was indicated for some treatments and was not correlated with observed DNA damage. Application of a chemical dispersant increased the genotoxic potential rather by the increased bioavailability of dissolved and particulate oil compounds. Nonetheless, the dispersant induced a clear oxidative stress response, indicating a relevance for general toxic stress. Results showed that the combination of different in vitro assays is important for a reliable genotoxicity assessment. Especially, the ZF-L capable of active metabolism and DNA repair seems to be a promising model for WAF testing.

In situ burning (ISB) is discussed to be one of the most suitable response strategies to combat oil spills in extreme conditions. After burning, a highly viscous and sticky residue is left and may over time pose a risk of exposing aquatic biota to toxic oil compounds. Scientific information about the impact of burn residues on the environment is scarce. In this context, a comprehensive ISB field experiment with approx. 1000L IFO 180 was conducted in a fjord in Greenland. The present study investigated the toxicity of collected ISB residues to early life stages of zebrafish ( Danio rerio ) as a model for potentially exposed pelagic organisms. The toxicity of ISB residues on zebrafish embryos was compared with the toxicity of the initial (unweathered) IFO 180 and chemically dispersed IFO 180. Morphological malformations, hatching success, swimming behavior, and biomarkers for exposure (CYP1A activity, AChE inhibition) were evaluated in order to cover the toxic response on different biological organization levels. Across all endpoints, ISB residues did not induce greater toxicity in zebrafish embryos compared with the initial oil. The application of a chemical dispersant increased the acute toxicity most likely due to a higher bioavailability of dissolved and particulate oil components. The results provide insight into the adverse effects of ISB residues on sensitive life stages of fish in comparison with chemical dispersant application.

Bioanalytical equivalents (BEQs) of mixtures and environmental samples are widely used to reflect the potential threat of pollutants in the environment and can be obtained by bioassays or using chemical analysis combined with relative potencies (REPs). In this study, the relationships between bioassay-detected BEQs (Bio-BEQs) and chemically analyzed BEQs (Chem-BEQs) were studied. BEQs and REPs are correlated with effect level and the concentration-response curves of the reference standard and sample. Thus, effect level (e.g., EC10, EC25 and EC50) should be addressed for the BEQ values obtained from bioassays or chemical analyses. The previous prerequisites for REPs application (i.e., curves that are parallel and have the same maximum response) are redundant, and the use of REPs for the calculation of BEQs or in risk assessment should instead be based on the same effect level. For a complex mixture with many components, all active components can be regarded as dilutions of a standard compound for inducing a specific effect. Relative toxicity estimates based on EC50 ignore the contribution of weak-active components with maximum response below EC50 of the reference standard, especially in complex mixtures or environmental samples. REPs based on an effect level EC10 that can be clearly discriminated from background response are recommended for BEQ calculation. As an example, the aryl hydrocarbon receptor (AhR)-mediated activity of US EPA priority polycyclic aromatic hydrocarbons (PAHs) in RTL-W1 cells was used to assess the reliability of REPs for mixture toxicity prediction based on the effect level EC10.

Microplastic pollution has drawn the attention of both scientists and the public regarding their potential ecotoxicological risks. In the present study, we carried out aqueous exposure experiments to adult zebrafish with polystyrene microplastics (5 μm) at a wide range of concentrations (0.001-20 mg/L, equals to 14.5∼2.9 × 105 particles/mL). Our results showed the gastrointestinal tract (GIT) was the dominant microplastic accumulation site in zebrafish, followed by the gill, whereas no microplastics were detected in the brain or muscle. Microplastic accumulation in GIT did not cause obvious damages to intestinal villi in general. However, the thickness of muscularis layer in the foregut reduced by 32% after 1 mg/L (1.45 × 104 particles/mL) microplastic exposure. As there were no signs of oxidative stress or other histological changes found in the fish, we further investigated the energy-supplying influential factors. We found that the zebrafish became hyperactive after microplastic exposure, whose swimming distance had increased to 1.3-2.4 folds than that of control, and also stayed at manic and active states much longer. The fish behavioural alteration is probably attributed to the particulate matter stimulation and the up-regulation of estrogen contents. Results also showed that the excessive movements of zebrafish also led to decreased glucose and acetaldehyde metabolite contents and increased amino acid amounts, which further proved the shortage of energy-supplying substances. Therefore, the present study suggests that micro-sized microplastics can induce obvious behavioural abnormality at concentrations that some other toxicological endpoints may not warn effects.

Pharmaceuticals in surface waters have raised significant concern in recent years for their potential environmental effects. This study identified that at present a total of 477 substances (including 66 metabolites and transformation products) have been analyzed in European surface waters. Around 60% (284) of these compounds belonging to 16 different therapeutic groups were positively detected in one or more of 33 European countries. To conveniently and effectively prioritize potential high-risk compounds, an optimized method that considers the frequency of concentrations above predicted no effects levels was developed on the basis of the traditional method, and it was then used to identify and screen candidate priority pollutants in European surface waters. The results proved the feasibility and advantages of the optimized method. Pharmaceuticals detected in European surface waters were classified into 5 categories (high, moderate, endurable, negligible and safe) depending on their potential environmental effects and the distribution of pharmaceuticals. Circa 9% (45 out of 477) analyzed compounds showed a potential environmental risk to aquatic ecosystems. Among these 45 compounds, 12 compounds were indicated to have high environmental risk in aquatic environments, while 17 and 7 compounds showed moderate and small-scale environmental risks, respectively.

Endocrine disrupting compounds (EDCs) emerged as a major concern for water quality in the last decade and have been studied extensively since. Besides typical natural and synthetic estrogens also petroleum product compounds such as some PAHs have been identified as potential EDCs, revealing endocrine disruption to be a relevant mode of action for crude oil toxicity. Hence, in the context of a comprehensive retro- or prospective risk assessment of oil spills the implementation of mechanism-specific toxicity such as endocrine disruption is of high importance. To evaluate the exposure risk for the aquatic biota, research focuses on water-soluble fractions underlying an oil slick that could be simulated via water-accommodated fractions (WAF). Against this background human (ERα-CALUX®) and yeast based (A-YES®) reporter gene bioassays were successfully optimized for the application in estrogenicity evaluation of the water-accommodated fraction (WAF) from a crude oil. Combining different approaches, the estrogenicity of the WAFs from a naphthenic North Sea crude oil was tested with and without the addition of a chemical dispersant addressing specific aspects of estrogenicity including the influence of biotransformation capacities and different salinity conditions. Both the WAF free from droplets (LEWAF) as well as the chemically dispersed WAF (CEWAF) gave indications of an ER-mediated estrogenicity with much stronger ERα agonists in the CEWAF treatment. Resulting estradiol equivalents of the WAFs were above the established effect-based trigger values for both bioassays. Results indicate that the dispersant rather increased the fraction of ER-activating crude oil compounds instead of interacting with the receptor itself. Only slight changes in estrogenic responses were observed when cells capable of active metabolism (T47D) were used instead of cells without endogenous metabolism (U2-OS) in the recombinant ER transactivation CALUX assay. With the yeast cells a higher estrogenic activity was observed in the experiments under elevated salinity conditions (6‰), which was in contrast to previous expectations due to typical decrease in dissolved PAH fraction with increasing salinity (salting-out effect) but might be related to increased cell sensitivity.

Zebrafish have been increasingly used for monitoring and assessing the effects of different contaminants in the aquatic environments. In the present study, zebrafish embryos and larvae were used to study the effects of the insecticide diazinon and the herbicide diuron in regard to occurrence of oxidative stress-related cellular responses, multixenobiotic resistance (MXR)-related efflux transporter activity—which represents the first line of defense against xenobiotics in many aquatic organisms—and responses of different molecular and biochemical biomarkers.