Environmentally relevant bisphenol A concentrations effects on the seagrass Cymodocea nodosa different parts elongation: perceptive assessors of toxicity

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Bisphenol A and its substitutes in the aquatic environment: Occurrence and toxicity assessment

Bisphenol A is classified as a high production volume chemical commonly used in the manufacture of polycarbonate plastics, epoxy resins and thermal paper. The endocrine disrupting properties of this xenobiotic have led to the restriction and prohibition of its use in many consumer products. To date, many chemical compounds with a chemical structure similar to bisphenol A have been used in consumer products as its replacement. The ubiquitous occurrence of bisphenol A and its substitutes in the environment and their endocrine activity as well as adverse effects on aquatic organisms is a global concern, especially because many available literature reports show that many substitutes (e.g. bisphenol AF, bisphenol AP, bisphenol B, bisphenol C, bisphenol F, bisphenol G, bisphenol FL, tetrabromobisphenol A) exert adverse effects on aquatic organisms, similar to, or even stronger than bisphenol A. Therefore, the objective of this paper is to provide a comprehensive overview of the production, sources, occurrence and associated toxicity, as well as the endocrine activity of bisphenol A and its substitutes on aquatic species. The environmental levels and ecotoxicological data presented in this review allowed for a preliminary assessment and prediction of the risk of bisphenol A and its substitutes for aquatic organisms. Furthermore, the data collected in this paper highlight that several compounds applied in bisphenol A-free products are not safe alternatives and regulations regarding their use should be introduced.

Impacts of bisphenol A on growth and reproductive traits of submerged macrophyte Vallisneria natans

Bisphenol A (BPA) is considered a contaminant of emerging concern and interferes with the normal activities of living organisms. The toxicity of BPA is evident in animals and terrestrial plants. However, the response of aquatic plants to low BPA concentrations is still unclear. In the present study, effects of varying BPA loadings (targeting at 0.01, 0.1, and 1 mg/L) on the growth and reproductive traits of the dioecious annual submerged macrophyte Vallisneria natans were assessed through a 5-month experiment. The results showed that BPA inhibited the elongation of V. natans leaves but resulted in an increase in leaf number and ramet number under the highest BPA loading treatment (targeting at 1 mg/L). In addition, detectable biochemical changes in the total carbon and soluble sugar contents were found, which both were significantly higher at the highest BPA loading treatment. However, the total biomass did not alter significantly after the BPA treatments, indicating that BPA did not induce direct toxic effects on the growth of V. natans. At the highest BPA loading treatment, female individuals of V. natans allocated less number for ramet than male ones, showing a clear sexual dimorphism. No significant differences between the five treatments were found for the flower or fruit traits, while the germination rate was significantly inhibited for the seeds collected from the highest BPA loading treatment. In conclusion, V. natans tolerated low concentrations of BPA by making a trade-off between ramet (leaf) number and leaf elongation, as well as modulating the total carbon and soluble sugar contents. However, serious consequence of decline in seed viability implied that the impact of BPA on plant reproduction were usually underestimated.

Bisphenol A in the environment and recent advances in biodegradation by fungi

Bisphenol A (BPA) is a compound used in the manufacture of a wide variety of everyday materials that, when released into the environment, causes multiple detrimental effects on humans and other organisms. The reason for this review is to provide an overview of the presence, distribution, and concentration of BPA in water, soil, sediment, and air, as well as the process of release and migration, biomagnification, and exposure mechanisms that cause various toxic effects in humans. Therefore, it is important to seek efficient and economic strategies that allow its removal from the environment and prevent it from reaching humans through food chains. Likewise, the main removal techniques are analyzed, focusing on biological treatments, particularly the most recent advances in the degradation of BPA in different environmental matrices through the use of ligninolytic fungi, non-ligninolytic fungi and yeasts, as well as the possible routes of metabolic processes that allow their biotransformation or biodegradation due to their efficient extracellular enzyme systems. This review supports the importance of the application of new biotechnological tools for the degradation of BPA.

Copper uptake kinetics and toxicological effects of ionic Cu and CuO nanoparticles on the seaweed Ulva rigida

Copper ion (Cu²⁺) and copper oxide (CuO) nanoparticle (NP) ecotoxicity are of increasing concern as they are considered to be a potential risk to marine systems. This study represents the first attempt to evaluate CuO NP impacts on the seaweeds and Cu²⁺ on the chlorophyte Ulva rigida. Effects on oxidative stress, antioxidant defence markers, photosystem II function, thalli growth, and cell viability in U. rigida exposed for 4 up 72 h to1 and 5 mg L^-1 Cu²⁺ and CuO NPs were examined. Hydrogen peroxide (H₂O₂) generation, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and growth inhibition seemed to be reliable and early warning markers of toxicity. The most important variables of the principal component analysis (PCA): H₂O₂ generation, antioxidant stress markers, and growth-based toxicity index, were higher at 1 mg L^-1 CuO NPs compared to CuSO₄ and at 5 mg L^-1 CuSO₄ compared to CuO NPs. Intracellular uptake kinetics fit well to the Michaelis-Menten equation. The higher toxicity at 5 mg L^-1 CuSO₄ compared to 1 mg L^-1 was due to the higher Cu uptake with increasing concentration, suggesting and higher accumulation ability. On the contrary, 1 mg L^-1 CuO NPs induced more strongly toxicity effects than 5 mg L^-1. The relatively stronger effect of CuO NPs at 1 mg L^-1 than the respective CuSO₄ concentration could be attributed to the higher rate of initial uptake (V_c) and the mean rate of Cu uptake [C_max/(2 × K_m)] at CuO NP treatment. The intracellular seaweed experimental threshold of Cu, which coincided with the onset of oxidative stress, was within the Cu concentration range recorded in Mediterranean Ulva spp., indicating that it may pose a substantial risk to marine environments.

Genotoxic potential of bisphenol A: A review

Bisphenol A (BPA), as a major component of some plastic products, is abundant environmental pollutant. Due to its ability to bind to several types of estrogen receptors, it can trigger multiple cellular responses, which can contribute to various manifestations at the organism level. The most studied effect of BPA is endocrine disruption, but recently its prooxidative potential has been confirmed. BPA ability to induce oxidative stress through increased ROS production, altered activity of antioxidant enzymes, or accumulation of oxidation products of biomacromolecules is observed in a wide range of organisms - estrogen receptor-positive and -negative. Subsequently, increased intracellular oxidation can lead to DNA damage induction, represented by oxidative damage, single- and double-strand DNA breaks. Importantly, BPA shows several mechanisms of action and can trigger adverse effects on all organisms inhabiting a wide variety of ecosystem types. Therefore, the main aim of this review is to summarize the genotoxic effects of BPA on organisms across all taxa.

The Enzymatic and Non-Enzymatic Antioxidant System Response of the Seagrass Cymodocea nodosa to Bisphenol-A Toxicity

The effects of environmentally relevant bisphenol A (BPA) concentrations (0.3, 1 and 3 μg L⁻¹) were tested at 2, 4, 6 and 8 days, on intermediate leaves, of the seagrass Cymodocea nodosa. Hydrogen peroxide (H₂O₂) production, lipid peroxidation, protein, phenolic content and antioxidant enzyme activities were investigated. Increased H₂O₂ formation was detected even at the lowest BPA treatments from the beginning of the experiment and both the enzymatic and non-enzymatic antioxidant defense mechanisms were activated upon application of BPA. Elevated H₂O₂ levels that were detected as a response to increasing BPA concentrations and incubation time, led to the decrease of protein content on the 4th day even at the two lower BPA concentrations, and to the increase of the lipid peroxidation at the highest concentration. However, on the 6th day of BPA exposure, protein content did not differ from the control, indicating the ability of both the enzymatic and non-enzymatic mechanisms (such as superoxide dismutase (SOD) and phenolics) to counteract the BPA-derived oxidative stress. The early response of the protein content determined that the Low Effect Concentration (LOEC) of BPA is 0.3 μg L⁻¹ and that the protein content meets the requirements to be considered as a possible early warning “biomarker” for C. nodosa against BPA toxicity.

Growth, pigment changes, and photosystem II activity in the aquatic macrophyte Lemna minor exposed to bisphenol A

As a result of its high production, bisphenol A (BPA) has become ubiquitous in aquatic and terrestrial habitats. In this study, we investigated the toxicity of BPA at 10 mg L^-1 on Lemna minor after 7 days of exposure under controlled conditions according to ISO 20079. BPA statistically reduced the total frond number and frond area, while frond number per colony was significantly elevated in BPA-treated group. However, no change was recorded in root number, while root length was significantly reduced by BPA. BPA also decreased the content of Chl a, Chl b, Chl a + b, and carotenoid by 36%, 44%, 38%, and 32%, respectively, versus the control leading to a decrease in the quantum yield of photosystem II. In addition, non-photochemical quenching (NPQ) values were 2.4- and 4.5-fold higher in light than in dark conditions for control and BPA-treated plants, respectively. Thus, there is a significant activation (61.8%; p<0.01) of PSII photoprotection mechanism (NPQ) in BPA-treated plants compared to control but without removing the negative effect of BPA on PSII. The total amount of soluble sugars was reduced by 40% compared to control, and starch accumulation was mainly observed in fronds exposed to BPA. Even if the response patterns of Lemna minor based on fresh and dry weight measurements were less sensitive in our experiment conditions, further studies should be addressed since BPA represents a threat to the dynamic equilibrium governing aquatic ecosystems.

Comparative studies on the response of Zostera marina leaves and roots to ammonium stress and effects on nitrogen metabolism

Coastal eutrophication has resulted in the rapid loss and deterioration of seagrass beds worldwide. The high concentration of ammonium in eutrophic aquatic environments has been invoked as the main cause. In this study, leaves and roots of the seagrass Zostera marina were treated with simulated eutrophic seawater with elevated ammonium concentrations. The tolerance to ammonium stress and mechanism of nitrogen metabolism detoxification in different tissues were investigated. The results showed that high ammonium stress significantly affected the growth of leaves and had a negative effect on photosynthesis. The root activity of Z. marina was not inhibited at ammonium concentrations of ≤100 mg/L, indicating that the roots exhibited tolerance to ammonium stress. Increasing ammonium concentrations led to a higher increase of ammonium and free amino acid (FAA) contents in leaves than in roots. However, nitrogen storage decreased in Z. marina leaves after high ammonium treatments. The enzyme activity and gene expression of glutamine synthetase (GS) in roots were significantly higher than in the leaves even under ammonium stress. Meanwhile, ammonium stress increased the enzyme activities and gene expression of glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) in roots, which suggested that the roots had a strong ability to assimilate ammonium under ammonium stress. In contrast, although the GOGAT and GDH activity and gene expression in the leaves were initially increased, they significantly decreased when the ammonium concentration exceeded 100 mg/L. These results indicated that the concentration of 100 mg/L might be a threshold marking a transition from tolerance to toxicity for the leaves. Our study demonstrates that Z. marina leaves could be prone to higher damage than roots because the mechanism of ammonium assimilation in leaves is more susceptible to ammonium toxicity.

Evaluation of the spatiotemporal effects of bisphenol A on the leaves of the seagrass Cymodocea nodosa

The organic pollutant bisphenol A (BPA) causes adverse effects on aquatic biota. The present study explored the toxicity mechanism of environmentally occurring BPA concentrations (0.03-3 μg L^-1) on the seagrass Cymodocea nodosa intermediate leaf photosynthetic machinery. A "mosaic" type BPA effect pattern was observed, with "unaffected" and "affected"" leaf areas. In negatively affected leaf areas cells had a dark appearance and lost their chlorophyll auto-fluorescence, while hydrogen peroxide (H₂O₂) content increased time-dependently. In the "unaffected" leaf areas, cells exhibited increased phenolic compound production. At 1 μg L^-1 of BPA exposure, there was no effect on the fraction of open reaction centers (q_P) compared to control and also no significant effect on the quantum yield of non-regulated non-photochemical energy loss in PSII (Φ_ΝΟ). However, a 3 μg L^-1 BPA application resulted in a significant Φ_ΝΟ increase, even from the first exposure day. Ultrastructural observations revealed electronically dense damaged thylakoids in the plastids, while effects on Golgi dictyosomes and the endoplasmic reticulum were also observed at 3 μg L^-1 BPA. The up-regulated H₂O₂ BPA-derived production seems to be a key factor causing both oxidative damages but probably also triggering retrograde signalling, conferring tolerance to BPA in the "unaffected" leaf areas.

Hydrogen Peroxide Production by the Spot-Like Mode Action of Bisphenol A

Bisphenol A (BPA), an intermediate chemical used for synthesizing polycarbonate plastics, has now become a wide spread organic pollutant. It percolates from a variety of sources, and plants are among the first organisms to encounter, absorb, and metabolize it, while its toxic effects are not yet fully known. Therefore, we experimentally studied the effects of aqueous BPA solutions (50 and 100 mg L^-1, for 6, 12, and 24 h) on photosystem II (PSII) functionality and evaluated the role of reactive oxygen species (ROS) on detached leaves of the model plant Arabidopsis thaliana. Chlorophyll fluorescence imaging analysis revealed a spatiotemporal heterogeneity in the quantum yields of light energy partitioning at PSII in Arabidopsis leaves exposed to BPA. Under low light PSII function was negatively influenced only at the spot-affected BPA zone in a dose- and time-dependent manner, while at the whole leaf only the maximum photochemical efficiency (Fv/Fm) was negatively affected. However, under high light all PSII photosynthetic parameters measured were negatively affected by BPA application, in a time-dependent manner. The affected leaf areas by the spot-like mode of BPA action showed reduced chlorophyll autofluorescence and increased accumulation of hydrogen peroxide (H₂O₂). When H₂O₂ was scavenged via N-acetylcysteine under BPA exposure, PSII functionality was suspended, while H₂O₂ scavenging under non-stress had more detrimental effects on PSII function than BPA alone. It can be concluded that the necrotic death-like spots under BPA exposure could be due to ROS accumulation, but also H₂O₂ generation seems to play a role in the leaf response against BPA-related stress conditions.