Assessment of hormonal activities and genotoxicity of industrial effluents using in vitro bioassays combined with chemical analysis

Chemical safety screening of products - better proactive

The increasing pressure to ensure product safety in a global market comes up against the current practice of targeting only known hazardous compounds in product safety analysis. However, product safety refers not only to known but also to unknown or hidden hazards that are very important to know and avoid. Shortcomings and limitations of currently used technologies seem to cause an obvious discrepancy between intended and actual consumer protection. Products are not as safe as claimed by stakeholders. An existing but overlooked proactive safety screening with a prioritization strategy is brought into focus as it offers a unique solution. It can handle the complexity of a product with thousands of compounds of unknown identity and unknown toxicity and can figure out the important hazardous compounds, both known and unknown. Using hardly any sample preparation and the effect detection at an early position in the workflow is a game changer not to overlook hazardous compounds. All analytical technologies are needed, but the key is the re-arrangement of the instrument order, i.e. firstly hazard-related screening (effect first) and secondly, focus on identification of prioritized hazardous compounds. Such a proactive safety screening revealed previously unknown hazardous compounds in products on the market claimed to be safe. The highly sustainable, affordable, and all-in-one 2LabsToGo-Eco with easy-to-use planar bioassays empowers stakeholders to implement proactive safety screening and dynamic risk management. The transition to greater efficacy in consumer protection needs incentives and the critical review aims to stimulate a debate.

Impact of sample acidification and extract storage on hormone receptor-mediated and oxidative stress activities in wastewater

An underemphasized aspect of sampling strategies in effect-based in vitro testing is to determine suitable collection and preparation techniques. In the current study, the impact of sample acidification on bioactivities was assessed using in vitro bioassays for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and the oxidative stress response (Nrf2 activity). Sampling was conducted at a recently upgraded Swedish wastewater treatment plant. Future plans for the treated wastewater include reuse for irrigation or as a potential drinking water source. In the AR and Nrf2 assays, acidification decreased bioactivities in the wastewater influent sample extracts, whereas acidification increased bioactivities following further treatment (disc filtration). In the ER assay, acidification had no impact on the observed bioactivities in the sample extracts. A secondary objective of the study was to assess the stability of the sample extracts over time. Lower activities were detected in the ER and AR assays in all extracts after storage for approximately 1 year. Nrf2 activities did not decrease over time, but rather increased in some of the acidified sample extracts. Overall, the findings suggest that sampling strategies involving acidification may need to be tailored depending on the selected bioassay(s) and the type of wastewater treatments being assessed.

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

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

Risk assessments of emerging contaminants in various waters and changes of microbial diversity in sediments from Yangtze River chemical contiguous zone, Eastern China

Over recent decades, increasing chemical contamination has greatly affected aquatic life and human health, even though most contaminants are present at low concentrations. The large-scale chemical industrial parks (CIPs) concentrated in the Yangtze River Delta account for over half of the total in China, and Jiangsu Province occupies one fifth of the Yangtze River Delta. Inevitably, the ecosystems could be affected by these CIPs. In this study, we collected 35 water and 12 sediment samples from the Yangtze River (Taizhou section) surrounding waters adjacent to concentrated CIPs and determined their cumulative chemical levels to be 0.2 to 28.4 μg/L and cumulative detections to be 11 to 39 contaminants with a median of 20 contaminants. 61 out of 153 screened chemicals were detected from at least one sampling site, and 6 contaminants, mostly semi-volatile organic compounds, appeared at all sites. Among these detected chemicals, di-n-octyl phthalate and dibutyl phthalate were at the highest levels. Ecological assessment revealed that 4-chloroaniline, phenol and dibutyl phthalate possibly would induce adverse effects on Yangtze River (Taizhou) ecosystems. Further aided with an evaluation of integrated biomarker response (IBR) index, it was found that site W06 (downstream of Binjiang CIP wastewater inlet) was the location in greatest need of urgent action. As a result, the microbial diversity of sediments in the Yangtze River mainstream was significantly higher than that of tributaries, where CIPs wastewater entered.

Profile and removal of bisphenol analogues in hospital wastewater, landfill leachate, and municipal wastewater in South China

The presence of bisphenol analogues (BPs) in wastewater can have adverse effects to organisms in the environment. However, knowledge of the wastewater sources, such as hospitals and landfills, as well as the removal of BPs are still limited. Fifteen BPs were investigated in hospital, landfills, and municipal wastewater treatment plants (WWTPs) in South China. Eleven BPs were detected in various source wastewaters, and bisphenol A (BPA) is generally the dominant pollutant. In 4 hospitals, the total concentrations of BPs (∑BPs) in hospital wastewater and treated wastewater ranged from 122 to 1040 ng/L. In the landfill, ∑BPs in leachate and treated leachates were 32,130 and 145 ng/L, respectively. In 5 municipal WWTPs, ∑BPs was up to 17,200 ng/L in influents, 502 ng/L in effluents, and 291 ng/g in sludges. The modified A²/O process exhibited best removal profile for BPs, while the UNITANK process had no advantages. The annual mass load estimates of hospital treated wastewater, landfill treated leachate, and WWTP effluents in Guangdong Province, South China, were 630, 9.46, and 4697 kg/y, respectively. The risk quotient values in source effluents revealed low to medium estrogenic risks to receiving rivers. Control measures should be applied to further remove BPs not only from WWTP effluents but also from other sources.

Variation and comparison of biotoxicity during typical biological treatment of dyeing wastewater

In present study, dyeing wastewater samples were collected from three typical dyeing wastewater treatment plants in Wujiang, Shengze and Shanghai, China. Physicochemical properties and biotoxicity indicators (luminescent bacteria acute toxicity and umu genotoxicity) were tested and the relationships among them were analyzed. The results revealed that two biotoxicity indicators varied significantly among different treatment units of three plants. After treatment by plant A, luminescent bacteria acute toxicity of dyeing wastewater reduced effectively, while umu genotoxicity increased significantly. Two biotoxicity indicators exhibited decrease and increase trends during the treatment processes of plant B and plant C, respectively. Correlation analysis indicated that there was little correlation among biotoxicity indicators and physicochemical properties, meanwhile two kinds of biotoxicity indicators were relatively independent. Therefore, it was recommended that comprehensive evaluation of dyeing wastewater toxicity needs the combination of various biotoxicity indicators, and the relationship among biotoxicity indicators and physicochemical properties of dyeing wastewater should be established individually. The results of this study would offer a general understanding and evaluation of biotoxicity during actual dyeing wastewater treatment processes and provide database for toxicity reduction and management of dyeing wastewater.

Distribution and mass loads of xenoestrogens bisphenol a, 4-nonylphenol, and 4-tert-octylphenol in rainfall runoff from highly urbanized regions: A comparison with point sources of wastewater

This study pays a special attention to three phenolic endocrine disrupting compounds (EDCs), - bisphenol A (BPA), 4-nonylphenol (4-NP), and 4-tert-octylphenol (4-t-OP) - that are present in urban environments, resultant of several anthropogenic activities that can be also carried through rainfall runoff. We investigated the distributions of BPA, 4-NP, and 4-t-OP in Pearl River basin and estimated the mass loads in rainfall runoff, wastewater treatment plant (WWTP) effluents, and industrial wastewater from urbanized Huizhou and Dongguan regions. These three phenolic EDCs were detected frequently in tributaries and mainstream of Dongjiang River with the maximum 4-NP concentrations of 14,540 ng/L in surface waters and 3088 ng/g in sediments. BPA showed high concentrations in rainfall runoff samples with maximum concentrations of 5873 and 2397 ng/L in Huizhou and Dongguan regions, respectively, while concentrations for 4-NP and 4-t-OP were detected at tens to hundreds of nanograms per liter. Mass loads of phenolic EDCs from rainfall runoff were 3-62 times higher than those of WWTP effluents, suggesting rainfall runoff is an important source of phenolic EDCs into receiving waters. Sources and tributaries showed median to high estrogenic risks, while low to median risks were found in mainstream, implying the source control should be focused.

Identification of (anti-)androgenic activities and risks of sludges from industrial and domestic wastewater treatment plants

The annual production of sludges is significant all over the world, and large amounts of sludges have been improperly disposed by random dumping. The contaminants in these sludges may leak into the surrounding soils, surface and groundwater, or be blown into the atmosphere, thereby causing adverse effects to human health. In this study, the (anti-)androgenic activities in organic extracts of sludges produced from both industrial and domestic wastewater treatment plants (WWTPs) were examined using reporter gene assay based on MDA-kb2 cell lines and the potential (anti-)androgenic risks were assessed using hazard index (HI) based on bioassays. Twelve of the 18 samples exhibited androgen receptor (AR) antagonistic activities, with AR antagonistic equivalents ranging from 1.2 × 10² μg flutamide/g sludge to 1.8 × 10⁴ μg flutamide/g sludge; however, no AR agonistic activity was detected in any of the tested samples. These 12 sludges were all from chemical WWTPs; no sludges from domestic WWTPs displayed AR antagonistic activity. Aside from wastewater source, treatment scale and technology could also influence AR antagonistic potencies. The HI values of all the 12 sludges exceeded 1.0, and the highest HI value was above 3.0 × 10³ for children; this indicates that these sludges might cause adverse effects to human health and that children are at a greater risk than adults. The anti-androgenic potencies and risks of the subdivided fractions were also determined, and medium-polar and polar fractions were found to have relatively high detection rates and contribution rates to the AR antagonistic potencies and risks of the raw sample extracts.

Occurrence, mass loads and risks of bisphenol analogues in the Pearl River Delta region, South China: Urban rainfall runoff as a potential source for receiving rivers

Bisphenol (BP) analogues are widely used as industrial materials and various product additives and are inevitably released into environment. However, knowledge on the sources of different BPs, especially those from urban rainfall runoff to the receiving rivers is very limited. In this study, 15 BPs were determined in surface water, sediments, wastewater treatment plant (WWTP) and rainfall runoff samples in the Pearl River region, South China. Eleven BPs were detected in surface water and sediments of the Pearl Rivers. BPA was the dominant compound up to 2080 ng/L in surface and 1970 ng/g in sediments, followed by BPF, BPS, BPTMC and BPAF. In WWTPs, 10, 9 and 8 BPs were detected in influents, effluents and excess sludges, respectively, with total BPs (ΣBPs) concentrations in effluents still at thousands ng/L, suggesting incompletely removal of BPs. Five BPs were detected in urban rainfall runoff samples, with the ΣBPs concentrations up to 7740 ng/L. Mass loads of ΣBPs from the rainfall runoff (5800 kg/y) were almost equivalent to the source from WWTPs (7370 kg/y) in the region, implying that the urban rainfall runoff was a potential source for BPs into the receiving river. The calculated estrogenic activity contributed by BPs showed low to median risks in sources and receiving rivers. But BPs are always as mixtures with other potential endocrine disrupting chemicals (EDCs) which probably pose high estrogenic activity risks. Hence, effective measures should be taken to decrease the input of EDCs from sources to receiving rivers.

Global review of phthalates in edible oil: An emerging and nonnegligible exposure source to human

This work investigated the presence of seven major phthalates in nine different kinds of edible oils (i.e. olive, rapeseed, peanut, sesame, tea seed, corn, soybean, sunflower, and blended oil) and their potential impacts on human. The respective total average phthalates concentrations in the oils studied were found to be 6.01, 2.79, 2.63, 2.03, 1.73, 1.66, 1.57, 1.26, and 0.72 mg/kg. On the other hand, the seven main phthalates in the edible oils with the average concentration ranked from high to low were in order of DiNP, DEHP, DiDP, DBP, DiBP, DEP, and BBP, with 0.90, 0.81, 0.79, 0.71, 0.22, 0.17, and 0.10 mg/kg, respectively. The estimated maximum human daily intakes (EDI) of DEHP, DBP, DiBP, DiNP, BBP, DEP, and DiDP via edible oils were determined to be 552, 2996, 121, 356, 268, 66, and 563 μg/p/d, respectively. It was further revealed that the maximum human EDI of DEHP, DBP, BBP, and DiBP through consumption of edible oils were 2.92, 6.79, 1.24, and 1.06 times higher than those via bottled water. The calculated average estrogenic equivalence (EEQ) values of the seven major phthalates in edible oils fell into the range of 2.7-958.1 ng E₂/L, which were 45-396 times of those in bottled water. With published works, the complete distributions of 15 phthalates in nine kinds of edible oils were established and assessed for the health risks based on EDI and EEQ. This work provided the first evidence that edible oil is a potential source of phthalates, thus the potential adverse estrogenic effects on human health should need to be assessed in a holistic manner.

Toxicological and ecotoxicological evaluation of the water quality in a large and eutrophic freshwater lake of China

Effect-based methods (EBMs) are recommended as holistic approach for diagnosis and monitoring of water quality; however, the application of EBMs is still scare in China. In the present study, water quality of the freshwater lake Taihu (China) was investigated by EBMs. Different types of water samples were collected from three bays of the lake during 2015, 2016 and 2017. A battery of seven effect-based bioassays, including both specific and non-specific toxicity assays, was used. The bioassay battery was recently suggested based on joint activities of the EU project SOLUTIONS and the NORMAN network on emerging pollutants and is also under discussion for being implemented into monitoring activities in the context of the European Water Framework Directive (WFD). Adverse effects were observed towards the primary producer, primary consumer and fish, indicating the potential ecotoxicity of water in Taihu Lake. Mutagenic and estrogenic effects were found in the Ames fluctuation assay and ERα CALUX (Chemically Activated Luciferase Gene-eXpression) assay, respectively, highlighting the potential risks on human health. Algal growth inhibition and mutagenic effects can be observed during each of the three years. Acute toxicity towards Daphnia magna and estrogen receptor agonistic effects were found in at least one of the samples collected in 2016 and 2017, but not in 2015. The endpoints for fish toxicity in the Danio rerio fish embryo test included both lethal and additionally several sublethal effects (only for samples from 2017) and were not compared between years. Algal growth inhibition, fish embryo toxicity, mutagenic effect and estrogenicity were observed in each of the three bays, while Daphnia acute toxicity was only found in Zhushan Bay. Taking together, this study provides a big picture on the water quality of Taihu Lake. The battery of effect-based tools is promising to be a routine for water quality monitoring in China.

Do progestins contribute to (anti-)androgenic activities in aquatic environments?

Unknown compounds with (anti-)androgenic activities enter the aquatic environment via municipal wastewater treatment plants (WWTPs). Progestins are well-known environmental contaminants capable of interfering with androgen receptor (AR) signaling pathway. The aim of the present study was to determine if 15 selected progestins have potential to contribute to (anti-)androgenic activities in municipal wastewaters and the respective recipient surface waters. AR-specific Chemically Activated LUciferase gene eXpression bioassay in agonistic (AR-CALUX) and antagonistic (anti-AR-CALUX) modes and liquid chromatography tandem atmospheric pressure chemical ionization/atmospheric photoionization with hybrid quadrupole/orbital trap mass spectrometry operated in high resolution product scan mode (LC-APCI/APPI-HRPS) methods were used to assess (anti-)androgenic activity and to detect the target compounds, respectively. The contribution of progestins to (anti-)androgenic activities was evaluated by means of a biologically and chemically derived toxicity equivalent approach. Androgenic (0.08-59 ng/L dihydrotestosterone equivalents - DHT EQs) and anti-androgenic (2.4-26 μg/L flutamide equivalents - FLU EQs) activities and progestins (0.19-75 ng/L) were detected in selected aquatic environments. Progestins displayed androgenic potencies (0.01-0.22 fold of dihydrotestosterone) and strong anti-androgenic potencies (9-62 fold of flutamide). Although they accounted to some extent for androgenic (0.3-29%) and anti-androgenic (4.6-27%) activities in influents, the progestins' contribution to (anti-)androgenic activities was negligible (≤2.1%) in effluents and surface waters. We also tested joint effect of equimolar mixtures of target compounds and the results indicate that compounds interact in an additive manner. Even if progestins possess relatively strong (anti-)androgenic activities, when considering their low concentrations (sub-ng/L to ng/L) it seems unlikely that they would be the drivers of (anti-)androgenic effects in Czech aquatic environments.

Effect-based trigger values for in vitro and in vivo bioassays performed on surface water extracts supporting the environmental quality standards (EQS) of the European Water Framework Directive

Effect-based methods including cell-based bioassays, reporter gene assays and whole-organism assays have been applied for decades in water quality monitoring and testing of enriched solid-phase extracts. There is no common EU-wide agreement on what level of bioassay response in water extracts is acceptable. At present, bioassay results are only benchmarked against each other but not against a consented measure of chemical water quality. The EU environmental quality standards (EQS) differentiate between acceptable and unacceptable surface water concentrations for individual chemicals but cannot capture the thousands of chemicals in water and their biological action as mixtures. We developed a method that reads across from existing EQS and includes additional mixture considerations with the goal that the derived effect-based trigger values (EBT) indicate acceptable risk for complex mixtures as they occur in surface water. Advantages and limitations of various approaches to read across from EQS are discussed and distilled to an algorithm that translates EQS into their corresponding bioanalytical equivalent concentrations (BEQ). The proposed EBT derivation method was applied to 48 in vitro bioassays with 32 of them having sufficient information to yield preliminary EBTs. To assess the practicability and robustness of the proposed approach, we compared the tentative EBTs with observed environmental effects. The proposed method only gives guidance on how to derive EBTs but does not propose final EBTs for implementation. The EBTs for some bioassays such as those for estrogenicity are already mature and could be implemented into regulation in the near future, while for others it will still take a few iterations until we can be confident of the power of the proposed EBTs to differentiate good from poor water quality with respect to chemical contamination.

17β-Estradiol induces cyto-genotoxicity on blood cells of common carp (Cyprinus carpio)

17β-Estradiol, a natural hormone present at high concentrations in aquatic ecosystems, affects and modifies endocrine function in animals. In recent years research workers have expressed concern over its potential effects on aquatic organisms; however, little is known about its capacity to induce genetic damage or the pro-apoptotic effects of such damage on fish. Therefore, this study aimed to evaluate 17β-estradiol-induced cyto-genotoxicity in blood cells of the common carp Cyprinus carpio exposed to different concentrations (1 ng, 1 μg and 1 mg L^-1). Peripheral blood samples were collected and evaluated by comet assay, micronucleus test, determination of caspase-3 activity and TUNEL assay at 12, 24, 48, 72 and 96 h of exposure. Increases in frequency of micronuclei, TUNEL-positive cells and caspase-3 activity were observed, particularly at the highest concentration. In contrast, the comet assay detected significant increases at 24 and 96 h with the 1 μg and 1 ng L^-1 concentrations respectively. The set of assays used in the present study constitutes a reliable early warning biomarker for evaluating the toxicity induced by this type of emerging contaminants on aquatic species.

Advanced Approaches to Model Xenobiotic Metabolism in Bacterial Genotoxicology In Vitro

During the past 30 years there has been considerable progress in the development of bacterial test systems for use in genotoxicity testing by the stable introduction of expression vectors (cDNAs) coding for xenobiotic-metabolizing enzymes into bacterial cells. The development not only provides insights into the mechanisms of bioactivation of xenobiotic compounds but also evaluates the roles of enzymes involved in metabolic activation or inactivation in chemical carcinogenesis. This review describes recent advances in bacterial genotoxicity assays and their future prospects, with a focus on the development and application of genetically engineering bacterial cells to incorporate some of the enzymatic activities involved in the bio-activation process of xenobiotics. Various genes have been introduced into bacterial umu tester strains encoding enzymes for genotoxic bioactivation, including bacterial nitroreductase and O-acetyltransferase, human cytochrome P450 monooxygenases, rat glutathione S-transferases, and human N-acetyltransferases and sulfotransferases. Their application has provided new tools for genotoxicity assays and for studying the role of biotransformation in chemical carcinogenesis in humans.

Vitellogenin induction and reduced fecundity in zebrafish exposed to effluents from the City of Bulawayo, Zimbabwe

Industrial and municipal effluents regularly pollute water bodies and cause various toxic effects to aquatic life. Because of the diverse nature of industrial processes and domestic products, urban effluents are often tainted with various anthropogenic endocrine disrupting chemicals that may interfere with the reproductive physiology of aquatic fauna. In this study, we tested effluents from the City of Bulawayo for the presence of estrogenic endocrine disrupting chemicals and their effects on fish gonads and fecundity. Effluents were collected from two sewage treatment plants (STPs), which receive largest volume of industrial effluents from the City, and from a textile factory. Male and female zebrafish (Danio rerio) were exposed to effluents and analyzed for vitellogenin induction, gonad alterations, and fertility. Male zebrafish exposed to effluent from Thorngrove STP had significantly higher (p ≤ 0.05) vitellogenin compared to control. Textile effluent caused adverse gonad alterations such as oocyte atresia (females) and increased proportion of spermatogonia (males) which could lead to reduced fertility. Textile effluent (5% v/v) and Thorngrove effluent also caused a decline in fertilization success of breeding groups of zebrafish. The results of this study show the potential effects of effluent pollution and the occurrence of EDCs in developing countries. This underscores the need to effectively prevent pollution of environmental water bodies from industrial and municipal sewage treatment plant effluents. We recommend a follow-up study to monitor the effects of the effluents on feral fish in effluent polluted downstream dams of Bulawayo.

Raw and biologically treated paper mill wastewater effluents and the recipient surface waters: Cytotoxic and genotoxic activity and the presence of endocrine disrupting compounds

Paper mill effluents are complex mixtures containing different toxic compounds including endocrine-disrupting (EDCs) and genotoxic compounds. In the present study non-concentrated raw and biologically treated wastewaters from two paper mill plants with different paper production technologies i) Paper mill A uses virgin fibres, and ii) Paper mill B uses recycled fibres for paper production and the corresponding receiving surface waters, were assessed for their cytotoxic/genotoxic activity with SOS/umuC, Ames MPF 98/100 Aqua, and comet assay with human hepatoma HepG2 cells. In addition the levels of seven selected EDCs were quantified in wastewater samples and receiving surface waters. All investigated EDCs were confirmed in raw and biologically treated effluents from both paper mills with concentrations being markedly higher in Paper mill B effluents. In the receiving surface waters three of the studied EDCs were determined downstream of both paper mills effluent discharge. The wastewater samples and the recipient surface water samples from Paper mill A were not mutagenic for bacteria and did not induce DNA damage in HepG2 cells. On the contrary, half of the raw wastewater samples from Paper mill B were mutagenic whereas biologically treated wastewater and the recipient surface water samples were negative. In HepG2 cells most of the raw and biologically treated wastewater samples from Paper mill B as well as surface water samples collected downstream of Paper mill B effluent discharge induced DNA damage. The results confirmed that genotoxic contaminants were present only in wastewaters from Paper mill B that uses recycled fibres for paper production, and that the combined aerobic and anaerobic wastewater treatment procedure efficiently reduced contaminants that are bacterial mutagens, but not those that induce DNA damage in HepG2 cells. This study highlights that in addition to chemical analyses bioassays are needed for a comprehensive toxicological evaluation of complex wastewater samples.

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore, to identify causative pollutants with harmful biological effects, chemical analyses for the pollutants listed in water quality standards is not sufficient, and single-endpoint bioassays may underestimate adverse effects. Thus, a battery of bioassays based on different MOAs is required for the comprehensive detection of harmful biological effects. In conclusion, for genotoxicity screening of surface waters, the SOS/umu test system by using different strains combined with the CBMN assay was a useful approach.

Pesticide Mixture Toxicity in Surface Water Extracts in Snails (Lymnaea stagnalis) by an in Vitro Acetylcholinesterase Inhibition Assay and Metabolomics

Many chemicals in use end up in the aquatic environment. The toxicity of water samples can be tested with bioassays, but a metabolomic approach has the advantage that multiple end points can be measured simultaneously and the affected metabolic pathways can be revealed. A current challenge in metabolomics is the study of mixture effects. This study aims at investigating the toxicity of an environmental extract and its most abundant chemicals identified by target chemical analysis of >100 organic micropollutants and effect-directed analysis (EDA) using the acetylcholinesterase (AChE) bioassay and metabolomics. Surface water from an agricultural area was sampled with a large volume solid phase extraction (LVSPE) device using three cartridges containing neutral, anionic, and cationic sorbents able to trap several pollutants classes like pharmaceuticals, pesticides, PAHs, PCBs, and perfluorinated surfactants. Targeted chemical analysis and AChE bioassay were performed on the cartridge extracts. The extract of the neutral sorbent cartridge contained most of the targeted chemicals, mainly imidacloprid, thiacloprid, and pirimicarb, and was the most potent AChE inhibitor. Using an EDA approach, other AChE inhibiting candidates were identified in the neutral extract, such as carbendazim and esprocarb. Additionally, a metabolomics experiment on the central nervous system (CNS) of the freshwater snail Lymnaea stagnalis was conducted. The snails were exposed to the extract, the three most abundant chemicals individually, and a mixture of these. The extract disturbed more metabolic pathways than the three most abundant chemicals individually, indicating the contribution of other chemicals. Most pathways perturbed by the extract exposure overlapped with those related to exposure to neonicotinoids, like the polyamine metabolism involved in CNS injuries. Metabolomics for the straightforward comparison between a complex mixture and single compound toxicity is still challenging but, compared to traditional biotesting, is a promising tool due to its increased sensitivity.

Causes of endocrine disrupting potencies in surface water in East China

Surface water is essential for human health and ecological diversity, but some endocrine disrupting chemicals are detectable. Both thyroid receptor (TR) and androgen receptor (AR) agonistic/antagonistic potencies in grade II surface water in East China were investigated using reporter gene assays. While none of the water exhibited agonistic potency, significant AR and TR antagonistic potencies were detectable. TR antagonistic equivalents (TR-AntEQ) and AR antagonistic equivalents (AR-AntEQ) ranged from 3.6 to 76.1 μg dibutyl phthalate/L and from 2.3 to 242.6 μg flutamide/L, respectively. The TR and AR antagonistic potencies in the Yangtze River watershed were highlighted, with equivalents greater than the lowest observable effect concentration (LOEC) of dibutyl phthalate and flutamide, respectively. Phthalate esters (PAEs) being the most abundant explained most of the TR antagonistic potency, contributing more than 65% of the TR-AntEQ and diisobutyl phthalate (DiBP) was the major contributor. In most surface waters studied, PAEs contributed little of the AR-AntEQ, but the frequently detected octylphenol, nonylphenol and benzo[a]pyrene might be responsible.

Characteristics of estrogenic/antiestrogenic activities during the anoxic/aerobic biotreatment process of simulated textile dyeing wastewater

HOA and HON were key fractions involved in increasing antiestrogenic activity and humic/fulvic acid in them could mask estrogenic activity.

Understanding the implications of dissolved organic carbon when assessing antagonism in vitro: An example with an estrogen receptor assay

Both estrogenic and anti-estrogenic activity has been observed in water samples. Some studies have suggested that dissolved organic carbon (DOC), which can be co-extracted during sample enrichment, contributes to the apparent antagonistic effect. DOC has a high sorption capacity for the estrogen receptor (ER) agonist 17β-estradiol, which may reduce the available 17β-estradiol concentration in the antagonist testing mode and potentially lead to apparent antagonism. The aim of the study was to determine the influence of DOC when assessing antagonism in an ER reporter gene assay. The presence of DOC shifted the 17β-estradiol concentration-effect curve to higher concentrations, increasing the nominal EC50 value by up to 0.3 log units. However, this shift was within the usual variability associated with repeated measurements of concentration-effect curves. This shift was not due to DOC being an antagonist itself or interfering with fluorescence measurements, but was due to DOC reducing the bioavailability of 17β-estradiol. This was demonstrated by modelling the DOC sorption corrected 17β-estradiol concentration using experimental DOC-water partition coefficients (KDOC). While the shift in the 17β-estradiol concentration-effect curve was minor, sorption of 17β-estradiol to DOC can have an impact when assessing antagonism. At the EC50 agonist concentration, both modelled and experimental results showed that DOC at concentrations similar to that co-extracted in water samples caused suppression of the agonist at levels that would be classified as antagonism. The suppression was less pronounced at the EC80 agonist concentration, hence this is recommended when assessing antagonism of DOC rich samples, such as surface water and wastewater.

Estrogenic activity and identification of potential xenoestrogens in a coking wastewater treatment plant

In this study, the estrogenic activities in influent and effluents of coking wastewater from different treatment stages were studied using Yeast Estrogen Screen (YES) bioassays. Raw extracts were further fractioned to identify the potential xenoestrogens combined with YES bioassays and gas chromatography-mass spectrometry analysis. Influent, primary effluent, and anaerobic effluent showed high estrogenic activities, with potencies of 1136±269, 1417±320, and 959±69 ng/L of 17β-estradiol (E2) equivalent (EEQ), respectively. The potency of estrogenic activity was gradually removed through the treatment processes. In the final effluent, the estrogenic activity was reduced to 0.87 ng EEQ/L with a total removal efficiency of more than 99%, suggesting that the estrogenic activity was almost completely removed in the coking wastewater. For the fractions of raw extracts, bioassay results showed that the estrogenic activities were mostly present in the polar fractions. Correlation analysis between estrogenic activities and responses of identified chemicals indicated that potential xenoestrogens were the derivatives of indenol, naphthalenol, indol, acridinone, fluorenone, and carbazole. The estrogenic activity in the final effluent was higher than the predicted no effect concentration (PNEC) for E2, implying that the discharged effluent would probably exert estrogenic activity risk to the aquatic ecosystem in "the worst-case scenario."

Using combined bio-omics methods to evaluate the complicated toxic effects of mixed chemical wastewater and its treated effluent

Mixed chemical wastewaters (MCWW) from industrial park contain complex mixtures of trace contaminants, which cannot be effectively removed by wastewater treatment plants (WWTP) and have become an unignored threat to ambient environment. However, limited information is available to evaluate the complicated toxic effects of MCWW and its effluent from wastewater treatment plant (WTPE) from the perspective of bio-omics. In this study, mice were exposed to the MCWW and WTPE for 90 days and distinct differences in the hepatic transcriptome and serum metabolome were analyzed by digital gene expression (DGE) and proton nuclear magnetic resonance ((1)H-NMR) spectra, respectively. Our results indicated that disruption of lipid metabolism in liver and hepatotoxicity were induced by both MCWW and WTPE exposure. WTPE is still a health risk to the environment, which is in need of more attention. Furthermore, we demonstrated the potential ability of bio-omics approaches for evaluating toxic effects of MCWW and WTPE.

Occurrence and potential causes of androgenic activities in source and drinking water in China

The increased incidences of disorders of male reproductive tract as well as testicular and prostate cancers have been attributed to androgenic pollutants in the environment. Drinking water is one pathway of exposure through which humans can be exposed. In this study, both potencies of androgen receptor (AR) agonists and antagonists were determined in organic extracts of raw source water as well as finished water from waterworks, tap water, boiled water, and poured boiled water in eastern China. Ten of 13 samples of source water exhibited detectable AR antagonistic potencies with AR antagonist equivalents (Ant-AR-EQs) ranging from <15.3 (detection limit) to 140 μg flutamide/L. However, no AR agonistic activity was detected in any source water. All finished water from waterworks, tap water, boiled water, and poured boiled water exhibited neither AR agonistic nor antagonistic activity. Although potential risks are posed by source water, water treatment processes effectively removed AR antagonists. Boiling and pouring of water further removed these pollutants. Phthalate esters (PAEs) including diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) were identified as major contributors to AR antagonistic potencies in source waters. Metabolites of PAEs exhibited no AR antagonistic activity and did not increase potencies of PAEs when they coexist.