Determination of the soil hazardous concentrations of bisphenol A using the species sensitivity approach

Evaluation of Bisphenol S (BPS) toxicity on the reproductive system of Channa striatus: Insights for environmental risk assessment

Aquatic ecosystems face significant exposure to endocrine-disrupting chemicals (EDCs), which can mimic, block, or alter the synthesis of endogenous hormones. Bisphenol A (BPA), a widely known EDC, has been phased out from consumer products due to concerns about its potential impacts on human health. In its place, bisphenol S (BPS), an organic compound, has been increasingly used in the production of polycarbonate plastics, epoxy resins, thermal receipt papers, and currency. Vitellogenin (Vtg), a yolk precursor protein synthesized in the liver and present in oviparous fish, particularly males, serves as a pertinent biomarker for studying the effects of estrogenic EDCs on fish. This study aimed to assess the impact of BPS on reproductive parameters and hepatic vitellogenin expression in Channa striatus. The LC50 of BPS was determined to be 128.8 mg/L. Experimental groups included control and BPS-exposed fish, with sub-lethal concentrations of BPS (1 mg/L, 4 mg/L, and 12 mg/L) administered and effects monitored at seven- and twenty-one-day intervals. Significant decreases in gonadosomatic index (GSI), ova diameter, and fecundity were observed in BPS-exposed Channa striatus. Hepatic Vtg mRNA expression was downregulated in female and upregulated in male following BPS exposure. Serum hormone analysis confirmed the estrogenic activity of BPS. These findings underscore BPS's ability as an endocrine disruptor to interfere with hormone synthesis and disrupt spermatogenesis and oogenesis processes in Channa striatus. This research contributes to understanding the endocrine-disrupting effects of BPS on aquatic organisms, highlighting potential ecological implications and the need for continued monitoring and regulatory considerations.

Intermediate-tier options in the environmental risk assessment of plant protection products for soil invertebrates-Synthesis of a workshop

The European environmental risk assessment (ERA) of plant protection products follows a tiered approach. The approach for soil invertebrates currently consists of two steps, starting with a Tier 1 assessment based on reproduction toxicity tests with earthworms, springtails, and predatory mites. In case an unacceptable risk is identified at Tier 1, field studies can be conducted as a higher-tier option. For soil invertebrates, intermediate tiers are not implemented. Hence, there is limited possibility to include additional information for the ERA to address specific concerns when the Tier 1 fails, as an alternative to, for example, a field study. Calibrated intermediate-tier approaches could help to address risks for soil invertebrates with less time and resources but also with sufficient certainty. A multistakeholder workshop was held on 2-4 March 2022 to discuss potential intermediate-tier options, focusing on four possible areas: (1) natural soil testing, (2) single-species tests (other than standard species), (3) assessing recovery in laboratory tests, and (4) the use of assembled soil multispecies test systems. The participants acknowledged a large potential in the intermediate-tier options but concluded that some issues need to be clarified before routine application of these approaches in the ERA is possible, that is, sensitivity, reproducibility, reliability, and standardization of potential new test systems. The definition of suitable assessment factors needed to calibrate the approaches to the protection goals was acknowledged. The aims of the workshop were to foster scientific exchange and a data-driven dialog, to discuss how the different approaches could be used in the risk assessment, and to identify research priorities for future work to address uncertainties and strengthen the tiered approach in the ERA for soil invertebrates. This article outlines the background, proposed methods, technical challenges, difficulties and opportunities in the ERA, and conclusions of the workshop. Integr Environ Assess Manag 2024;20:780-793. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Ethylene and ROS mediate root growth inhibition induced by the endocrine disruptor bisphenol A (BPA)

Bisphenol A (BPA) functions as a detrimental substance that disrupts the endocrine system in animals while also impeding the growth and development of plants. In our previous study, we demonstrated that BPA hinders the growth of roots in Arabidopsis by diminishing cell division and elongation, which is ascribed to the increased accumulation and redistribution of auxin. Here, we examined the mediation of ROS and ethylene in BPA-induced auxin accumulation and root growth inhibition. BPA enhanced ROS levels, and ROS increased auxin contents but reduced cell division activity and the expression of EXPA8 involved in root elongation. ROS scavenger treatment reversed BPA-triggered root growth retardation, auxin accumulation, and cell division inhibition. In addition, BPA induced ethylene, and ethylene synthesis inhibitor treatment reversed BPA-triggered root growth retardation and auxin accumulation. Taken together, ROS and ethylene are involved in BPA-inhibited cell elongation and cell division by mediating auxin accumulation and redistribution.

Analysis of impacts of exogenous pollutant bisphenol-A penetration on soybeans roots and their biological growth

Bisphenol A (BPA) is a common chemical used in plastic production. BPA, which has the potential to be poisonous to plants, has lately emerged as a serious environmental concern owing to its extensive usage and release patterns. Prior study has only looked at how BPA affects plants up to a certain stage in their growth. The precise mechanism of toxicity, penetration of BPA, and damage to internal root tissues remains unknown. Therefore, the goal of this study was to examine the hypothesized mechanism for BPA-induced root cells by studying the effects of bisphenol A (BPA) on the ultrastructure and function of root tip cells of soybean plants. We looked at plant changes in root cell tissues after BPA exposure. Further, the biological characteristics that responded to BPA stress were investigated, and the accumulation of BPA in the root, stem, and leaf of the soybean plant was systematically investigated by using FTIR and SEM analysis. The uptake of BPA is a key internal factor that contributes to changes in biological characteristics. Our findings provide insight into how BPA could alter plant root growth, which might contribute new knowledge toward a better scientific appraisal of the possible dangers of BPA exposure for plants.

Phytoremediation potential, antioxidant response, photosynthetic behavior and rhizosphere bacterial community adaptation of tobacco (Nicotiana tabacum L.) in a bisphenol A-contaminated soil

Bisphenol A (BPA) is an emerging organic pollutant, widely distributed and frequently detected in soil in recent years. BPA toxicity is a problem that needs to be solved in terms of both human health and agricultural production. Up to now, the toxic effect of BPA and its mechanism of action on plants, as well as the possibility of using plants to remediate BPA-contaminated soil, remain to be explored. In this study, six treatment groups were set up to evaluate the effects of different concentrations of BPA on the germination and growth of tobacco (Nicotiana tabacum L.) by medium experiments. Furthermore, the representative indexes of photosynthetic and antioxidant system were determined. Meanwhile, tobacco seedlings were cultivated in soil to further explore the effects of BPA on rhizosphere soil enzyme activity and bacterial community structure with or without 100 mg/kg BPA exposure. The enhancement of BPA removal efficiency from soil by phytoremediation using tobacco plants would also be estimated. Our results showed that high doses of BPA in solid medium remarkably inhibited tobacco seedling growth, and its toxicology effect was positively correlated with BPA concentration, while lower BPA exposure (< 20 mg/L) had little limitation on tobacco growth and induced hormesis effect, which was reflected mainly in the increase of root length. In pot experiments, the reducing of chlorophyll content (36.4%) and net photosynthetic rate (41.2%) meant the inhibition of tobacco photosynthetic process due to high concentration of BPA exposure (100 mg/kg) in soil. The increase of H2O2 and O2- content suggested that BPA could destroy the balance of reactive oxygen species (ROS) in plants. However, tobacco plants still presented a high removal efficiency of BPA at the concentration of 100 mg/kg in soil, which could reach to 80% within 30 days. Furthermore, it was indicated that tobacco cultivation changed the structure of rhizosphere soil bacterial communities and the relative abundance of some valuable strains, including Proteobacteria, Acidobacteria and other strains, which might be participated in the BPA removal process. In addition, the tobacco-soil microbial system had the potential to reverse the negative effects caused by BPA through stimulating microorganism associated with soil nutrient cycling. In summary, tobacco is a competitive plant in phytoremediation of BPA-contaminated soil, though the growth of tobacco could be inhibited at high concentration of BPA. Moreover, tobacco might promote the removal efficiency of BPA by regulating the rhizosphere bacteria communities.

Ecological risk assessment for perfluorohexanesulfonic acid (PFHxS) in soil using species sensitivity distribution (SSD) approach

Perfluorohexanesulfonic acid (PFHxS) is one of the persistent organic pollutants that has been recommended to be listed in Annex A of the Stockholm Convention. It has gained increasing attention in recent years due to its toxic effects. The guideline values of PFHxS are commonly associated with PFOS in various countries and regulatory agencies. In this study, multispecies bioassays were conducted to determine the ecological toxic effects of PFHxS, including plants, soil invertebrates, and soil microorganisms, which indicated the EC10/NOEC values ranged from 2.9 to 250 mg/kg. Where possible, logistic models were used to calculate the EC30 values for various endpoints. The species sensitivity distributions were employed to estimate the ecological investigation levels for PFHxS contamination in soils using toxicity results from literature and this study. The calculation using EC10/NOEC values from both literature and this study indicated a most conservative HC5 as 1.0 mg/kg (hazardous concentration for 5 % of the species being impacted). However, utilisation of EC30 values derived from this study resulted in a much higher HC5 for PFHxS in contaminated soils (13.0 mg/kg) which is at the higher end of the existing guideline values for PFOS for protecting ecological systems. The results obtained in this study can be useful in risk assessment processes to minimize any uncertainty using combined values with PFOS.

Species sensitivity distributions for ethylparaben to derive protective concentrations for soil ecosystems

Ethylparaben is used as an antifungal preservative. Although some countries have implemented regulations for human exposure to parabens, environmental regulations for ethylparaben have not been established. This study provides new toxicological data for ethylparaben, for which data regarding soil organisms were previously lacking. Although ethylparaben toxicity has been reported in other species, we present herein the first comprehensive study of its toxicity in soil organisms. We used 12 test species (Lycopersicon esculentum, Vigna radiata, Hordeum vulgare, Oryza sativa, Eisenia andrei, Folsomia candida, Lobella sokamensis, Caenorhabiditis elegans, Chlamydomonas reinhardtii, Chlorococcum infusionum, Chlorella sorokiniana, Chlorella vulgaris) from eight taxonomic groups for acute bioassays and nine test species (L. esculentum, V. radiata, H. vulgare, O. sativa, C. reinhardtii, C. infusionum, C. sorokiniana, and C. vulgaris) from five taxonomic groups for chronic bioassays. A suite of acute and chronic toxicity tests, using 21 soil species, was conducted to estimate EC₅₀ values, which facilitated the construction of species sensitivity distributions (SSDs) and the calculation of protective concentrations (PCs). Acute and chronic PC₉₅ values (protective concentration for 95% of species) for ethylparaben were estimated to be 14 and 5 mg/kg dry soil, respectively. To the best of our knowledge, this is the first study to evaluate the toxicity of ethylparaben to soil species and derive PCs for soil ecosystems based on SSDs. Therefore, the data presented in this study can be used as a basis for further investigations of paraben toxicity to the soil environment.

Thermal paper as a potential source of bisphenol A for humans and the environment: migration and ecotoxicological impact

The objective of this work was to evaluate thermal paper (TP) tickets used in Argentina as a potential source of bisphenol A (BPA) that could impact humans and the environment. BPA in TP was measured by HPLC ranging from 11.1 to 30.5 mg BPAg^-1. In order to estimate the impact on humans, dermal BPA estimated daily intake was calculated as being 79.3 ± 19.5 μgd^-1 for workers and 1.6 ± 0.4 μgd^-1 for the general population. To evaluate TP's impact on the environment, BPA migration from TP to water and soil was studied. In the case of water, 99.6% of the BPA tickets content migrated in 30 h, while 78.0% moved into the soil in 96 h. BPA degradation kinetics in soil and water were also carried out; while in soil 61.9% of BPA degraded in 120 h, no degradation was observed up to 120 h in tap or river water.Additionally, ecotoxicological effects of BPA on the earthworm Eisenia andrei, a representative terrestrial indicator, were studied performing bioassays on lethality, avoidance, and reproductive and enzymatic activity. BPA showed to be very toxic to E. andrei (LC₅₀ value in contact paper test of 17 μgcm^-2, 95% confidence interval 6-46 μgcm^-2, 24 h exposure) and also caused an increase of total cocoons for earthworms exposed to 10 and 50 mg BPA kg^-1 soil. Evasion response was observed at a concentration of 50 mg BPA kg^-1 soil, while no effect was observed on cholinesterases, carboxylesterases, and glutathione S-transferases activities (1, 10, and 50 mg BPA kg^-1 soil). Finally, a simple BPA degradation technology using water peroxide and radish (Raphanus sativus) tissue as catalyst was explored as a simple and domestic potential treatment to avoid BPA migration to the environment.

Exposure of preschool-aged children to highly-concerned bisphenol analogues in Nanjing, East China

Bisphenol analogues (BPs) have already attracted wide concern owing to the environmental and health risks they pose. The exposure pathways and health risk of preschool-aged children to BPs, however, are still poorly understood. In this study, we choose population survey with 184 preschool-age children from a suburb of Nanjing, eastern China, further reveal the internal and external exposures concentrations, distribution profiles, potential sources and eventually assess health risk of preschool-age children to eight kinds of BPs. The results verify that the 95th percentile (P95) concentrations of Ʃ8BPs ranged from 0.27 to 41.6 ng/mL, with a median concentration of 7.83 ng/mL in the urine samples. BPA, and BPF were the predominant BPs in urine, accounting for 67.3%, and 18.0% of Ʃ8BPs. The urine-based estimated daily intake (EDI) of Ʃ8BPs was 187 ng/kg body weight/day. Similarly, BPA, and BPF were the main BPs in the environmental exposure sources, accounting for 80.8%, and 11.7% of the total BPs. Moreover, the total external exposure dose of Ʃ8BPs via the environmental sources was 68.1 ng/kg body weight/day, including BPA (56 ng/kg body weight/day), BPF (7.68 ng/kg body weight/day) and BPB (2.62 ng/kg body weight/day). The oral intake of drinking water and food (vegetables and rice) was the main exposure pathways of BPs in preschool-age children. Furthermore, the hazard quotient (HQ) of BPs have been evaluated and the results show no occurrence of high risk. Additionally, the urine-based EDI was significantly higher than the total external exposure dose, suggesting the existence of other pathways of BP exposure to be further explored. To the best of our knowledge, this is the first study to conduct both an internal and external exposure assessment of BPs.

Sex-specific effects of bisphenol S with tissue-specific responsiveness in adult zebrafish: The antiandrogenic and antiestrogenic effects

This study investigates the adverse effects and the associated underlying mechanism of bisphenol S (BPS) exposure on reproductive endocrine activity in adult zebrafish. Fish were exposed for 21 days to different BPS concentrations (0, 8, 40, and 200 µg/mL) determined via the lowest observed adverse effect level (LOAEL, i.e., < EC₁₅ = 250 µg/mL) for zebrafish embryos. Exposure to 200 µg/mL BPS in female zebrafish in the absence of vitellogenic oocytes or the presence of degenerated oocytes in the ovary significantly decreased the biosynthesis of hepatic vitellogenin (VTG) mRNA, while hepatic VTG mRNA in male fish abundance was significantly elevated (P < 0.05). The levels of gonadal steroids were significantly increased in female zebrafish, while in male zebrafish, the levels of endogenous androgens were reduced (P < 0.05). However, the activities of 17β-estradiol and aromatase in male zebrafish were significantly elevated in all BPS exposure groups in male zebrafish (P < 0.05). Interestingly, thyroid hormone levels and residual whole-body BPS levels increased in female and male zebrafish with increasing exposure concentrations. A novel finding is that the response to BPS depends on zebrafish sex and tissue-specific responsiveness to the accumulation of BPS, suggesting that BPS may cause long-term environmental problems in adult zebrafish through tissue-specific suppression and hormonal imbalance.

Perspectives on microalgae as model organisms toward the standardization of soil algal toxicity test methods

When considering test species for soil ecotoxicity, the development of new model organisms is often suggested to increase the reliability of ecological risk assessments. Ubiquitous soil algae could offer potential test species for assessing various soil pollution levels. Currently, there are few reviews offering comprehensive perspectives on stressors-based toxicological studies using microalgae in soil media, with the majority of scholarly attention paid to the toxicological effects of freshwater algae or marine algae in aquatic ecosystems. In this review, we focus on current toxicological studies of microalgae assessed in soil-related media and suggest considerations for using microalgae in soil toxicity tests based on 22 publications (1998-2021). In addition, we analyzed characteristics of soil algae based on criteria for selecting test species and suggest that future research should be directed toward the standardization of soil algal toxicity test methods. This review discusses a promising method using soil algae as new test species for soil toxicity assessment as cost-effective and environmentally sound soil quality bioindicators. The review also addresses the lack of understanding behind how soil algae can serve as important test species for soil ecotoxicity.

Effects of endogenous and exogenous dissolved organic matter on sorption behaviors of bisphenol A onto soils

The transport of organic contaminants in groundwater might be greatly affected by coexistence of dissolved organic matter (DOM) from different sources. In this study, the effects of endogenous and exogenous DOMs (referred to as DOM_en and DOM_ex, respectively) on sorption behavior of bisphenol A (BPA) onto two reference soils were investigated by batch experiments and microscopic characterization. The results showed that BPA sorption onto soils was dominated by soil organic matter content and affected by DOM properties. The effect of DOM_en on BPA sorption was also related to the inorganic components of the two soils. The decrease of organic matter content reduced the sorption capacity of fluvo-aquic soil. However, because the content of available inorganic components in black soil was high, after removing DOM_en, more inorganic sites were exposed to increase the sorption capacity. In addition, DOM_en could form complexes with BPA in solution, thus the removal of DOM_en promoted BPA sorption onto black soil. Under the experimental conditions, contribution of DOM_ex to the total sorption of BPA onto both soils was not more than 30%. Results of dialysis experiments and soil sorption experiments indicated that effects of coexisting DOM_ex on BPA sorption was related to the affinity of DOM_ex to soils and complexation of BPA and DOM_ex. Since the affinity of DOM_ex to fluvo-aquic soil was relatively low, the complex of BPA and DOM_ex in solution was the main inhibition mechanism for BPA sorption. For black soil, higher complexation proportion of BPA with DOM_ex adsorbed onto soil which promoted BPA sorption onto soil. The findings are of significance for understanding the co-migration of DOM with BPA through soils.

Exposure to perfluorooctanesulfonate (PFOS) but not perflurorooctanoic acid (PFOA) at ppb concentration induces chronic toxicity in Daphnia carinata

Widespread environmental contamination of per- and polyfluoroalkyl substances (PFAS) is well established. Nevertheless, few studies have reported on the aquatic toxicity of PFAS, especially in indicator species such as Daphnia. In this study, the toxicity of two major PFAS, namely perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), was investigated on water flea (Daphnia carinata) using a battery of comprehensive toxicity tests, including a 48 h acute and a 21-day chronic assays. The survival, growth, and reproduction of D. carinata were monitored over a 21-day life cycle. PFOS exhibited higher toxicity than PFOA. The 48 h LC₅₀ values (confidence interval) based on acute toxicity for PFOA and PFOS were 78.2 (54.9-105) mg L^-1 and 8.8 (6.4-11.6) mg L^-1, respectively. Chronic exposure to PFOS for 21 days displayed mortality and reproductive defects in D. carinata at a concentration as low as 0.001 mg L^-1. Genotoxicity assessment using comet assay revealed that exposure for 96 h to PFOS at 1 and 10.0 mg L^-1 significantly damaged the organism's genetic makeup. The results of this study have great implications for risk assessment of PFOS and PFOA in aquatic ecosystems, given the potential of PFOS to pose a risk to Daphnia even at lower concentrations (1 μg L^-1).

UV Stimulated Manganese Dioxide for the Persulfate Catalytic Degradation of Bisphenol A

One of the most commonly produced industrial chemicals worldwide, bisphenol A (BPA), is used as a precursor in plastics, resins, paints, and many other materials. It has been proved that BPA can cause long-term adverse effects on ecosystems and human health due to its toxicity as an endocrine disruptor. In this study, we developed an integrated MnO2/UV/persulfate (PS) process for use in BPA photocatalytic degradation from water and examined the reaction mechanisms, degradation pathways, and toxicity reduction. Comparative tests using MnO2, PS, UV, UV/MnO2, MnO2/PS, and UV/PS processes were conducted under the same conditions to investigate the mechanism of BPA catalytic degradation by the proposed MnO2/UV/PS process. The best performance was observed in the MnO2/UV/PS process in which BPA was completely removed in 30 min with a reduction rate of over 90% for total organic carbon after 2 h. This process also showed a stable removal efficiency with a large variation of pH levels (3.6 to 10.0). Kinetic analysis suggested that 1O2 and SO4•− played more critical roles than •OH for BPA degradation. Infrared spectra showed that UV irradiation could stimulate the generation of –OH groups on the MnO2 photocatalyst surface, facilitating the PS catalytic degradation of BPA in this process. The degradation pathways were further proposed in five steps, and thirteen intermediates were identified by gas chromatography-mass spectrometry. The acute toxicity was analyzed during the treatment, showing a slight increase (by 3.3%) in the first 30 min and then a decrease by four-fold over 2 h. These findings help elucidate the mechanism and pathways of BPA degradation and provide an effective PS catalytic strategy.

Pregnancy-specific physiologically-based toxicokinetic models for bisphenol A and bisphenol S

Predictions from physiologically based toxicokinetic (PBTK) models can help inform human health risk assessment for potentially toxic chemicals in the environment. Bisphenol S (BPS) is the second most abundant bisphenol detected in humans in the United States, after bisphenol A (BPA). We have recently demonstrated that BPS, much like BPA, can cross the placental barrier and disrupt placental function. Differences in physicochemical properties, toxicokinetics, and exposure outcomes between BPA and other bisphenols prevent direct extrapolation of existing BPA PBTK models to BPS. The current study aimed to develop pregnancy-specific PBTK (p-PBTK) models for BPA and BPS, using a common p-PBTK model structure. Novel paired maternal and fetal pregnancy data sets for total, unconjugated, and conjugated BPA and BPS plasma concentrations from three independent studies in pregnant sheep were used for model calibration. The nine-compartment (maternal blood, liver, kidney, fat, placenta and rest of body, and fetal liver, blood and rest of body) models simulated maternal and fetal experimental data for both BPA and BPS within one standard deviation for the majority of the experimental data points, highlighting the robustness of both models. Simulations were run to examine fetal exposure following daily maternal exposure to BPA or BPS at their tolerable daily intake dose over a two-week period. These predictive simulations show fetal accumulation of both bisphenols over time. Interestingly, the steady-state approximation following this dosing strategy achieved a fetal concentration of unconjugated BPA to levels observed in cord blood from human biomonitoring studies. These models advance our understanding of bisphenolic compound toxicokinetics during pregnancy and may be used as a quantitative comparison tool in future p-PBTK models for related chemicals.

Rapid isolation and determination of bisphenol A in complicated matrices by magnetic molecularly imprinted electrochemical sensing

Because of its widespread distribution in the environment, bisphenol A (BPA) has become a global concern as an endocrine disruptor and a threat to human health through the food chain. Thus an efficient determination method is urgently needed for monitoring the levels of BPA. Herein, a novel electrochemical technique for the detection of BPA was performed by synchronous extraction and pre-concentration of BPA onto magnetic molecularly imprinted polymer (BMMIP), with subsequent readout on a magneto-actuated glassy carbon electrode (MGCE) by differential pulse voltammetry. Compared to the current methods of BPA determination, this BMMIP-based electrochemical sensor (BMMIPs@MGCE) not only simplifies the sample handling procedures substantially, without filtration, centrifugation, or other complex operations, but also can be easily renewed by a controllable magnetic field. As a sensor component, the core-shell BMMIPs exhibited excellent binding capacity (Q_e = 82.5 mg g^-1), short adsorption equilibrium time (30 s), and outstanding selectivity (k' = 7.239) towards BPA, as well as stability and recyclability. Importantly, the BMMIPs@MGCE sensor was successfully applied for the on-site monitoring and rapid detection of BPA in complicated real-world specimens, with good recoveries (81.31-119.77%) and a low limit of detection (0.133 μmol L^-1). Therefore, the stable and low-cost BMMIPs@MGCE sensor provides a new approach for the rapid determination of BPA in the field of environmental control and food safety. Graphical abstract.

Development of a new bisphenol A electrochemical sensor based on a cadmium(ii) porphyrin modified carbon paste electrode

In this study, the (5,10,15,20-tetrakis[(4-methoxyphenyl)]porphyrinato)cadmium(ii) complex ([Cd(TMPP)]) was successfully used as a modifier in a carbon paste electrode (CPE) and exploited for bisphenol A (BPA) detection. Analytical performance revealed two linear ranges from 0.0015-15 μM and 0.015-1.5 mM with a detection limit of 13.5 pM. The proposed method was implemented in water samples, which resulted in quantitative signals over the range 6.5-1000 μM with recoveries between 92.6 and 107.7% for tap water and between 96.6 to 106.0% for mineral water.

Different interaction performance between microplastics and microalgae: The bio-elimination potential of Chlorella sp. L38 and Phaeodactylum tricornutum MASCC-0025

Microplastics have recently been identified as an important emerging global problem which affects marine organisms and even humans. As a green and cost-effective environmental purification alternative, microalgae have attracted more and more attention. In this work, the interaction between microplastics (PP, PE, PET and PVC) and microalgae (Chlorella sp. L38 and Phaeodactylum tricornutum MASCC-0025) has been investigated. In addition, SEM and TEM characterization were also carried out to observe interactions between microplastics and microalgae. Experimental results indicated that there was an obvious inhibition effect of microplastics on Phaeodactylum tricornutum MASCC-0025 growth with inhibition ratio up to 21.1%. By contrast, Chlorella sp. L38 presented strong adaptive capacity to microplastics. The key active enzymes concentration variation and characterization (SEM and TEM) images also verified the toxic effect of tested microplastics on Chlorella sp. L38 and Phaeodactylum tricornutum MASCC-0025. The toxic effect might be explained by the possible leaching of additives of four tested microplastics. It could also be observed that microalgae have a potential to be used as an alternative bio-solution for microplastics treatment.

Hazards of bisphenol A (BPA) exposure: A systematic review of plant toxicology studies

The widespread use of bisphenol A (BPA) has led to its ubiquity in the natural environment. Thus, BPA is considered as a contaminant of emerging concern. Due to its widespread use, BPA has been detected in a range of soils and surface waters. This is of concern because BPA has been shown to elicit slight to moderate toxicity to plants. Based on current research and our own work, this paper reviews the toxic effects of BPA on plant growth and development, including effects at the macroscopic (e.g. seed germination, root, stem, and leaf growth) and microscopic (photosynthesis, uptake of mineral nutrient, hormone secretion, antioxidant systems, and reproductive genetic behavior) levels. Furthermore, this paper will discuss effects of BPA exposure on metabolic reactions in exposed plant species, and explore the use of high-efficiency plants in BPA pollution control (e.g. phytoremediation). Finally, this paper proposes some ideas for the future of BPA phytotoxicity research.

Ecological risk assessment for perfluorooctanoic acid in soil using a species sensitivity approach

Perfluorooctanoic acid (PFOA) is one of the persistent organic pollutants that has been listed in Annex A of the Stockholm Convention and has attracted attention owing to its endocrine-disrupting properties. However, there is currently little information available regarding the soil ecotoxicity of PFOA and the associated ecological risks. Accordingly, in this study, we sought to assess the soil ecological risk of PFOA based on a probabilistic approach using data obtained from multispecies bioassays and soil toxicity assessments, from which we generated soil species sensitivity distributions and estimated soil protective concentrations for PFOA. Using the latter distributions, we also undertook a probabilistic ecological risk assessment. On the basis of acute and chronic toxicity estimates obtained from bioassays involving eight soil-associated organisms from six diverse taxonomic groups, we could deduce that PFOA poses a negligible risk to soil ecosystems. However, we also found that this chemical may be more toxic than some of the established endocrine-disrupting chemicals such as bisphenol A, nonylphenol, and methylparaben, thereby indicating that further in-depth studies would be necessary to obtain a better understanding of the toxic potential of this chemical in the soil environment.

Evaluation of single and combined toxicity of bisphenol A and its analogues using a highly-sensitive micro-biosensor

Bisphenol analogues have been developed as alternatives to bisphenol A (BPA), a common chemical with potential adverse effects on human health. It is imperative to perform a fast and sensitive evaluation for the toxicity of these bisphenol analogues. This study introduces a label-free electrochemical biosensor based on a screen-printed electrode modified with the carboxylated multi-walled carbon nanotube/rhodamine B/gold nanoparticle. Ctenopharyngodon idella kidney (CIK) cells were used as the biological recognition agent to detect changes in electrochemical signals and indicate the cell viability. Only 20 μL of sample was required for detection, which was much lower than that of other conventional electrochemical methods (≥ 1 mL). This biosensor was examined for the cytotoxicity of BPA, bisphenol AF (BPAF), bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) to CIK cells. The half inhibition concentration (IC₅₀) values after 48 h of exposure indicated that the rank order of cytotoxicities was BPAF > BPB > BPA > BPF > BPS. The morphological changes in CIK cells after treatment with various bisphenols were investigated, and the combined toxicities of the binary bisphenol mixtures were determined. Potentially synergistic and additive effects were observed. These findings provide new insights into the cytotoxicity of bisphenol analogues.

Responses of seeds of typical Brassica crops to tetracycline stress: Sensitivity difference and source analysis

Antibiotics can induce adverse effects on plants. Brassica crop seeds, for their advantages, are used widely in seed germination test to investigate phytotoxicity of substances. However, their performances on evaluating antibiotics remain to be studied to select sensitive species for control of potential risks. In this work, common species of Chinese cabbage (Brassica rapa L.), edible rape (Brassica napus L.), and cabbage (Brassica oleracea L.) with three cultivars each were selected to compare and analyze the sensitivity difference of their seeds to tetracycline (TC) stress. Results showed that the ratio of axis to cotyledon (RAC) by fresh weight was an alternative endpoint besides radicle length (RL) in the test. The species sensitivity distribution (SSD) based on the effective concentrations causing x% inhibition (EC_x) in RL of seeds exposed to TC was applied to compare the sensitivity of seeds and estimate the hazardous concentration for x% species (HC_x). From the species-dependent sensitivity and the sensitivity difference of cultivars in the same species of seeds to TC, the performance of Chinese cabbage was the best in the study. The sensitivity of seeds to TC could be evaluated by EC₂₀ related to seed physical traits and germination indices, while the extent of seeds affected by TC could be evaluated by EC₅₀ related to the composition of seed storage reserves. We recommended that it was a new idea to analyze responses of different seeds to TC at large scale according to seed innate characteristics.

Quantitative assessment of photosynthetic activity of Chlorella (Class Trebouxiophyceae) adsorbed onto soil by using fluorescence imaging

In the present study, we evaluate our previously developed non-destructive soil algal toxicity method using species from a different class of algae; Class Trebouxiophyceae (Chlorella vulgaris and Chlorella sorokiniana), and directly measure the photosynthetic activity of these species adsorbed onto the soil as a new toxicity endpoint. This study shows that non-destructive soil algal toxicity method is applicable to non-specific test species, including those of Class Trebouxiophyceae as well as Class Chlorophyceae (Chlorococcum infusionum and Chlamydomonas reinhardtii). Furthermore, by performing photosynthesis image analysis, we verify that it is possible to measure the photosynthetic activity of soil algae Chlorella vulgaris adsorbed onto soils without the need to extract algal cells from the soil. We propose that the non-destructive soil algal toxicity method represents a novel technique for 1) evaluating pollutants in soil using non-specific algae and 2) conveniently and rapidly assessing the photosynthetic activity of soil algae Chlorella vulgaris adsorbed onto soil as a new toxicity endpoint.

Ultrasonic energy-assisted in-situ synthesis of Ru0/PANI/g-C3N4 nanocomposite: Application for picomolar-level electrochemical detection of endocrine disruptor (Bisphenol-A) in humans and animals

Bisphenol A (BPA) is an endocrine-disrupting chemical which resembles structurally the hormone estrogen. Even a trace amount of BPA can bind estrogen receptors resulting in the inducement of reproductive disorders, cancers and problems related to sexual growth such as manliness in female and womanliness in male. So the determination of BPA in human and animal bodies is very essential. For this purpose, a new nanocomposite composed of ruthenium nanoparticles, polyaniline and graphitic carbon nitride (Ru⁰/PANI/g-C₃N₄) has been synthesized ultrasonically (40 ± 3 kHz, 200 W). A modification on glassy carbon electrode (GCE) with the nanocomposite detects BPA in human and animal urine samples with wide linear range (0.01-1.1 µM) and the limit of detection is pico molar-level. The synthesized nanocomposite was characterized by Ultraviolet-Visible and Fourier Transform-Infra Red spectroscopies, thermo gravimetric analysis, transmission electron microscopy, X-ray diffraction study, energy dispersive X-ray analysis, and elemental mapping analysis. This sensing system is selective, stable and reusable, by which the detection of BPA in various physiological fluids is very much possible.

Effects of micro-sized polyethylene spheres on the marine microalga Dunaliella salina: Focusing on the algal cell to plastic particle size ratio

There is increasing concern about how microplastics (MPs) are impacting marine ecosystems. In particular, studies on how MPs impact microalgae are required because of the abundance of MPs and importance of green microalgae as primary producers. This study investigated how MPs that are larger (200 μm) than algal cells impact them, using the marine microalga Dunaliella salina as the test species. The microalga was exposed to polyethylene MPs for 6 days. Of interest, the growth and photosynthetic activity of D. salina was enhanced with exposure to MPs, while cell morphology (size and granularity) was not impacted. This phenomenon might be explained by trace concentrations of additive chemicals (endocrine disruptors, phthalates, stabilizers) that possibly leached from MPs promoting the growth and photosynthetic activity of D. salina. We also confirmed that MP size contributes towards determining how plastics affect microalgae. Specifically, as MP size shrinks compared to algal cell size, MPs have increasingly adverse effects. MPs of very small size (like nanoplastics) induce particularly adverse effects on algae. Further studies are required to establish the relationship between algal cell size and MP size.

Soil algae pipe assay: ex situ method for the evaluation of soil quality based on soil algae and its application to the pot test

We aimed to develop an ex situ method for evaluating soil quality using soil algae. The soil algae pipe assay involves application and sampling of algae and flow cytometry. As it can be performed in a greenhouse, the assay was effective for pot tests and conducive for soil quality assessment. This novel assay will enable broader toxicity testing.

The occurrence, potential toxicity, and toxicity mechanism of bisphenol S, a substitute of bisphenol A: A critical review of recent progress

Bisphenol S (BPS) has been introduced into the industry as a safer alternative to bisphenol A (BPA). The distribution of BPS has recently become an important issue worldwide, but investigations on the toxicity and mechanisms of BPS remain limited. A review of the literature reveals that BPS has widespread presence in environmental media, such as indoor dust, surface water, sediments, and sewage sludge. It has been detected in plants, paper products, some food items, and even in the human body. In addition, compared to BPA, BPS has a lower acute toxicity, similar or less endocrine disruption, similar neurotoxicity and immunotoxicity, and lower reproductive and developmental toxicity. The mechanisms underlying BPS toxicity may be related to the chemical properties of BPS in the human body, including interactions with estrogen receptors, and binding to DNA and some proteins, subsequently including exerting oxidative stress. However, further investigation on the potential risks of BPS to humans and its mechanisms of toxicity should be conducted to better understand and control the risks of such novel chemicals.

Effects of exogenous bisphenol A on the function of mitochondria in root cells of soybean (Glycine max L.) seedlings

Bisphenol A (BPA), a contaminant of emerging concern, can affect plant root growth by changing various physiological processes. Mitochondria are critical organelles that produce energy for growth. However, how BPA affects the function and ultrastructure of mitochondria and then plant root growth remains unclear. Here, we evaluated the lethality of BPA to root tip cells, investigated the energy production process of mitochondria, observed mitochondrial ultrastructure, and measured reactive oxygen species (ROS) and lipid peroxidation levels in mitochondria of soybean seedlings roots exposed to exogenous BPA. We found that low-dose BPA (1.5 mg/L) exposure induced limited toxicity in root tip cells, increased the activities of key enzymes (citrate synthase, succinate dehydrogenase, malate dehydrogenase and cytochrome C oxidase) involved in tricarboxylic acid cycle and oxidative phosphorylation, promoted adenosine triphosphate (ATP) synthesis, and increased ROS production in mitochondria. Higher doses of BPA (6.0, 17.2 mg/L) exposure caused massive cell death in root tips, decreased the above key enzyme activities and ATP production, and destroyed mitochondrial ultrastructure; meanwhile, these doses also significantly increased mitochondrial ROS and membrane lipid peroxidation levels. In conclusion, we found that mitochondria were significant subcellular sites through which BPA can damage plant roots. BPA-induced excessive ROS destroyed mitochondrial ultrastructure and inhibited key enzyme activities in energy production, resulting in decreased ATP synthesis and cell death in root tips. Our results demonstrated the effects of BPA on mitochondrial function and structure in plant root cells, providing new insights into understanding the underlying mechanisms of BPA affecting plant root growth.

Soil ecotoxicity study of DEHP with respect to multiple soil species

Di (2-ethylhexyl) phthalate or DEHP is classified as an endocrine-disrupting chemical. It is used as a plasticizer and pesticide additive. Moreover, it has a half-life of about 150-300 days. Thus, it is present in the soil environment and soil risk assessments for DEHP are needed. However, a number of studies have focused on the effects of DEHP in a single soil species. In this study, we conducted acute and chronic toxicity testing for DEHP using varied soil species, including plants, earthworms, soil algae, Collembola, and soil nematodes. In the plant toxicity test, no effect was observed at very high concentration except at some endpoints, and no effect was observed in the earthworm toxicity test. However, there were adverse effects on soil algae, Collembola, and nematodes. Notably, in the Collembola assays, the survival of adults decreased significantly at very high concentrations, whereas reproduction was hindered at low concentrations. Similar inhibition of reproduction was noted in the soil nematode assay. This suggests that DEHP has a greater influence on fertility than survival in the adult test species. However, besides hindered reproduction, no effect was observed on soil species at environmentally relevant concentrations.

Integrating bioavailability and soil aging in the derivation of DDT criteria for agricultural soils using crop species sensitivity distributions

Although the agricultural use of dichlorodiphenyltrichloroethane (DDT) has been banned for decades in many countries around the world, the detection of DDT and its metabolites in soils is very common due to their persistence. DDTs (sum of DDT and its metabolites) in farmland soils can be absorbed by crops at different levels and accumulate in the edible parts of agricultural products, posing threats to the health of human being. However, no information on the species sensitivity distribution (SSD) of crops with regard to DDTs has been reported due to the lack of enough bioavailability data and models to normalize the bioavailability data from different sources. Based on the bioconcentration factors of 17 crop species in Chinese soils obtained from previous studies, the criteria of DDTs in soils was derived according to the quality standard of agricultural products using the SSD method. Corrections for water content and aging time were conducted to normalize the data from different sources. The risk values of agricultural products at different concentration levels of DDTs in soils were also evaluated. It was found that oil crops are able to take up more DDTs than non-oil crops, so the soil criteria were calculated separately for oil crops and non-oil crops, which were 0.083 mg/kg and 0.29 mg/kg, respectively. With the residual concentrations of DDTs in soils at the range of 0.01-0.5 mg/kg, 0-8% of the agricultural products exceeded the permissible limits for DDTs which were set in the National Food Safety Standard of China. The results also demonstrated the feasibility for applying SSDs to derive the soil criteria of DDTs in order to ensure the safety of agricultural products. This work will provide information for the risk assessment and the establishment of soil environmental quality standards to ensure safe agricultural production.

Estimation of the soil hazardous concentration of methylparaben using a species sensitivity approach

Methylparaben, which is known to be an endocrine-disrupting chemical, is added to various personal care products, including cosmetics, and is also used as a food preservative and in pharmaceuticals. However, information on the toxicity of methylparaben in soil ecosystems is limited. Furthermore, unlike other substances such as metals and pesticides, there is no regulation of levels or safe concentrations of methylparaben in soil ecosystems. Therefore, the aims of this study were to evaluate the toxicity of methylparaben on soil species and to derive hazardous concentration (HC) values with respect soil ecosystem protection. We conducted acute bioassays on eight species within six taxonomic groups and chronic bioassays on five species within four taxonomic groups. On the basis of the results obtained, we derived an acute HC₅ value of 44 mg/kg soil and a corresponding chronic value of 27 mg/kg soil for methylparaben using species sensitivity distribution methodology following Australian and New Zealand guidelines. Given that there has been no proposed standard value for methylparaben in soil in any country, it was not possible to compare the HC values calculated in this study with regulation standard levels. Nevertheless, to our knowledge, this study is first to assess the toxicity of methylparaben against soil-inhabiting species and to estimate acute and chronic HCs for soil fauna and flora. The results of this study will provide valuable fundamental data for the establishment of acceptable levels of methylparaben in soil.

Impacts of exogenous pollutant bisphenol A on characteristics of soybeans

Bisphenol A (BPA) is an endocrine disruptor that is ubiquitous in the environment. Previous studies have focused on the effects of BPA on plants to assess the ecological risk of BPA in the environment. To evaluate the effects of BPA on plant biological characters more systematically, we investigated the biological characters of above-ground and under-ground organs of soybean plants exposed to BPA. Meanwhile, the mechanisms for the observed changes were also analyzed from the view of hormone levels and photosynthesis. The results showed that after exposure to 0.8 mg L-1 BPA for three days, indole-3-acetic acid (IAA) and gibberellic acid levels in roots increased significantly, and the IAA level increased in leaves, so the character indices of roots and leaves both increased. The IAA and ethylene levels in stems increased, but the character indices of stems did not increased. With higher BPA concentrations, especially exposure to 17.2 mg L-1 BPA, the levels of IAA, gibberellic acid, and zeatin decreased (except for the increased zeatin in leaves), and abscisic acid and ethylene levels increased; thus, all of the character indices significantly decreased. By comparing the changes in various biological characters, we found that leaf area, root surface area, and root length changed most significantly. In addition, changes in photosynthetic parameters provided initial causes for plant growth changes, and impacted biological characters. The changes of character indices were stronger when the BPA exposure time was prolonged, and after the removal of BPA, the character indices showed some recovery. Therefore, BPA exposure can regulate the changes in plant characters by influencing hormone levels and photosynthesis, and root surface area, root length, and leaf area were the most sensitive to BPA.

Species Sensitivity Distributions for Nonylphenol to Estimate Soil Hazardous Concentration

Nonylphenol is an endocrine-disrupting chemical that mimics estrogenic activity. Few studies have investigated the soil ecotoxicity of nonylphenol in the environment, based on probabilistic approaches. The present study generated soil toxicity data for nonylphenol through bioassays that determined the acute and chronic species sensitivity distributions and estimated the hazardous concentrations of nonylphenol in soil in order to protect soil ecosystems. We used eight soil-based organisms from six taxonomic groups for acute assays and five soil-based organisms from four taxonomic groups for chronic assays. The hazardous concentration values of nonylphenol in soil, based on acute and chronic species sensitivity distributions, were estimated using compiled data from the present study, as well as previous studies. This is the first study that generated sufficient data to develop species sensitivity distributions for nonylphenol in soil, and to determine hazardous concentrations of nonylphenol for soil environments.