Ecotoxicity and genotoxicity assessment of cytostatic pharmaceuticals

Comparative toxicology of algal cell extracts and pure cyanotoxins: insights into toxic effects and mechanisms of harmful cyanobacteria Raphidiopsis raciborskii

Ongoing research on cyanotoxins, driven by the socioeconomic impact of harmful algal blooms, emphasizes the critical necessity of elucidating the toxicological profiles of algal cell extracts and pure toxins. This study comprehensively compares Raphidiopsis raciborskii dissolved extract (RDE) and cylindrospermopsin (CYN) based on Daphnia magna assays. Both RDE and CYN target vital organs and disrupt reproduction, development, and digestion, thereby causing acute and chronic toxicity. Disturbances in locomotion, reduced behavioral activity, and weakened swimming capability in D. magna have also been reported for both RDE and CYN, indicating the insufficiency of conventional toxicity evaluation parameters for distinguishing between the toxic effects of algal extracts and pure cyanotoxins. Additionally, chemical profiling revealed the presence of highly active tryptophan-, humic acid-, and fulvic acid-like fluorescence compounds in the RDE, along with the active constituents of CYN, within a 15-day period, demonstrating the chemical complexity and dynamics of the RDE. Transcriptomics was used to further elucidate the distinct molecular mechanisms of RDE and CYN. They act diversely in terms of cytotoxicity, involving oxidative stress and response, protein content, and energy metabolism, and demonstrate distinct modes of action in neurofunctions. In essence, this study underscores the distinct toxicity mechanisms of RDE and CYN and emphasizes the necessity for context- and objective-specific toxicity assessments, advocating nuanced approaches to evaluate the ecological and health implications of cyanotoxins, thereby contributing to the precision of environmental risk assessments.

The concentration of dissolved organic matter impacts the neurobehavior in female zebrafish exposed to cyclophosphamide

Cyclophosphamide (CP) is a broad-spectrum anticancer drug for various cancers and frequently detected in aquatic environments, reaching concentrations up to 22 μg/L. However, there is limited understanding of the toxicities of CP with the presence of dissolved organic matter, a ubiquitous component in aquatic environments, in fish. In this study, we investigated the behaviors, morphological alterations of retina, and related gene transcripts in zebrafish exposed to CP (0 and 50 μg/L) and Humic acid (HA, a main component of DOM) at concentrations of 0, 3, 10, and 30 mg-C/L for 30 days. The results showed that, relative to the zebrafish in CP treatment, HA at 30 mg-C/L increased the locomotion (12.1 % in the light and 7.2 % in the dark) and startle response (9.7 %), while inhibiting the anxiety (12.5 %) and cognition of female zebrafish (24.6 %). The levels of transcripts of neurotransmitter- (tph1b and ache), neuroinflammation-(il-6 and tnfα) and antioxidant-(gpx) related genes in the brain of female adult were also altered by CP with the presence of HA. In addition, HA promoted the transgenerational effects of CP on the neurobehaviors. Therefore, HA can enhance potential neurotoxicity of CP in female fish through alteration neurotransmission related genes. Our findings provide new insights into the toxicity and underlying mechanisms of CP with the presence of dissolved organic matter, thereby contribute to a deeper understanding of the risks posed by CP in aquatic ecosystems.

Laccases as Effective Tools in the Removal of Pharmaceutical Products from Aquatic Systems

This review aims to provide a comprehensive overview of the application of bacterial and fungal laccases for the removal of pharmaceuticals from the environment. Laccases were evaluated for their efficacy in degrading pharmaceutical substances across various categories, including analgesics, antibiotics, antiepileptics, antirheumatic drugs, cytostatics, hormones, anxiolytics, and sympatholytics. The capability of laccases to degrade or biotransform these drugs was found to be dependent on their structural characteristics. The formation of di-, oligo- and polymers of the parent compound has been observed using the laccase mediator system (LMS), which is advantageous in terms of their removal via commonly used processes in wastewater treatment plants (WWTPs). Notably, certain pharmaceuticals such as tetracycline antibiotics or estrogen hormones exhibited degradation or even mineralization when subjected to laccase treatment. Employing enzyme pretreatment mitigated the toxic effects of degradation products compared to the parent drug. However, when utilizing the LMS, careful mediator selection is essential to prevent potential increases in environment toxicity. Laccases demonstrate efficiency in pharmaceutical removal within WWTPs, operating efficiently under WWTP conditions without necessitating isolation.

Hazard assessment of antineoplastic drugs and metabolites using cytotoxicity and genotoxicity assays

Antineoplastic drugs are among the most toxic pharmaceuticals. Their release into the aquatic ecosystems has been reported, giving rise to concerns about the adverse effects, including cytotoxicity and genotoxicity, that they may have on exposed organisms. In this study, we analyzed the cytotoxicity and genotoxicity of 5-fluorouracil (5-FU) and its metabolite alpha-fluoro-beta-alanine (3-NH2-F); gemcitabine (GEM) and its metabolite 2'-deoxy-2',2'-difluorouridine (2-DOH-DiF); as well as cyclophosphamide (CP) on the HepG2 cell line. Drug concentrations were based on those previously observed in the effluent of a major cancer hospital in Brazil. The study found that GEM, 2-DOH-DiF and 5-FU resulted in reduced cell viability. No reduction in cell viability was observed for CP and 3-NH2-F. Genotoxic assessment revealed damage in the form of nucleoplasmic bridges for CP and 3-NH2-F. The tested concentrations of all compounds resulted in significantly increased MNi and NBUDs. The results showed that these compounds induced cytotoxic and genotoxic effects in HepG2 cells at concentrations found in the environment. To the best of our knowledge, this study is the first to report on the cytogenotoxic impacts of the metabolites 3-NH2-F and 2-DOH-DiF in HepG2 cells. These findings may help in the development of public policies that could minimize potential environmental contamination.

Anticancer drugs in wastewater and natural environments: A review on their occurrence, environmental persistence, treatment, and ecological risks

The consumption of anticancer drugs (also known as chemotherapy drugs or antineoplastic drugs) has augmented over the last decades due to increased cancer incidence. Although there is an increasing concern about the presence of pharmaceutical compounds in natural environments and urban/domestic wastewater, anticancer drugs used in chemotherapy and anticancer medication have received less attention. In this review, the occurrence, environmental persistence, and known and potential ecological impacts of anticancer drugs is discussed. This review shows that these compounds are being increasingly detected in effluents of hospitals, influents and effluents of wastewater treatment plants, river surface water and sediments, groundwater, and even drinking water. Anticancer drugs can impact aquatic organisms such as algae, crustaceans, rotifers, and fish and may promote changes in soil and water microbial communities that may alter ecosystem functioning. Our knowledge of technologies for the removal of anticancer drugs is still limited, and these drugs can be dispersed in nature in a diffuse way in an uncontrolled manner. For this reason, an improved understanding of the presence, persistence, and ecological impacts of anticancer drugs in wastewater and natural environments is needed to help design management strategies, protect aquatic microorganisms, and mitigate potential ecological impacts.

Assessing the impact of antineoplastic drugs in the aquatic environment: State of the art and future perspective for freshwater organisms

Since the late 70s, the continuous pharmaceuticals` input into the environment has raised concerns regarding the eventual risk posed by such compounds to human and environmental health. A major group of pharmaceuticals in terms of environmental impact are the antineoplastic agents (AAs). Herein, we followed a systematic review method to retrieve antineoplastic agents (AAs') ecotoxicological information regarding freshwater species. In this analysis, data from diverse taxonomic groups, from microorganisms to vertebrate species, looked at different levels of biological organization, including cell lines. Furthermore, this review gathers ecotoxicological parameters (EC₅₀ and LC₅₀) for imatinib (IM), cisplatin (CisPt), and 5-fluorouracil (5-FU) in species sensitivity distribution (SSD) curves and estimates the hazard concentration (HC₅) considering the protection of 95% of the ecological community. Lastly, we suggest how we can improve AAs' Environmental Risk Assessment (ERA), considering potential adoptable toxicity endpoints, test duration, AAs metabolites testing, and AAs mixture exposure.

Assessing the risks of capecitabine and its active metabolite 5-fluorouracil to freshwater biota

Capecitabine (CAP, prodrug) and 5-fluorouracil (5-FU, its active metabolite) are two of the most prominent cytostatics, for which no clear picture can be drawn regarding potential concentrations of effect for freshwater biota, with CAP being grouped in the least studied cytostatic, whereas 5-FU has been classified as of no and of high environmental risk. Accordingly, the present work aimed to assess the ecotoxicity of CAP and 5-FU in three freshwater species, which included a 72-h assay with the producer Raphidocelis subcapitata; a 96-h assay with the invertebrate secondary consumer Hydra viridissima; and a 96-h assay with embryos of the vertebrate secondary consumer Danio rerio. The following endpoints were monitored: yield and population growth rate for the algae; mortality, morphological alterations, and post-exposure feeding rates for the cnidarian; and mortality, hatching, and malformations for the fish. Overall, organisms' sensitivity to CAP decreased in the following order: R. subcapitata > H. viridissima > D. rerio, whereas for 5-FU, it decreased in the following order: H. viridissima > D. rerio > R. subcapitata. For CAP, no median lethal effective concentrations (LC/EC₅₀) were possible to compute for D. rerio, with no significant mortality or malformations registered in embryos exposed at concentrations up to 800 mg L^-1. For R. subcapitata, the EC₅₀s were 0.077 and 0.63 mg L^-1 for yield and growth rate, respectively, and for H. viridissima, the EC_50,30 min for feeding was 22.0 mg L^-1. For 5-FU, no EC_50s could be computed for R. subcapitata, whilst the EC_50s for H. viridissima mortality and feeding were 55.4 and 67.9 mg L^-1, respectively, and for D. rerio, the LC_50,96 h and EC_50,96 h (hatching and abnormalities) were 4546, 4100, and 2459 mg L^-1, respectively. Assuming similar modes of action for both compounds and their co-occurrence, the combined risk quotient of the two chemicals was determined to be 7.97, which represents a risk for freshwater biota. Anticipating the increased consumption of these compounds and cancer development trends worldwide, these impacts may be further aggravated.

Contributions towards the hazard evaluation of two widely used cytostatic drugs

Cytostatic drugs are one of the most important therapeutic options for cancer, a disease that is expected to affect 29 million individuals by 2040. After being excreted, cytostatics reach wastewater treatment plants (WWTPs), which are unable to efficiently remove them, and consequently, they will be released into the aquatic environment. Due to the highly toxic properties of cytostatics, it is particularly relevant to evaluate their potential ecological risk. Yet, cytostatics toxicity data is still not available for various species. In this work, the ecotoxicity of two widely consumed cytostatics, cyclophosphamide (CYP-as a model cytostatic) and mycophenolic acid (MPA-as a priority cytostatic), was evaluated on three freshwater species-Raphidocelis subcapitata, Brachionus calyciflorus, and Danio rerio, and the risk quotient (RQ) was assessed. Both drugs significantly affected the yield and growth inhibition of the microalgae, while for rotifers, the least sensitive species, only significant effects were registered for CYP. These drugs also caused significant effects on the mortality and morphological abnormalities on zebrafish. The estimation of the RQ discloses that CYP seems to pose a low risk to aquatic biota while MPA poses a very high risk. Altogether, these results emphasize the need for more complete environmental risk assessments, to properly prioritize and rank cytostatics according to their potentially toxic effects on the environment and aquatic biota.

Transcriptomic responses to cytotoxic drug cisplatin in water flea Daphnia magna

Cytotoxic drugs have been recognized by the European Union as the potential threat in the aquatic environment. As a typical cytotoxic drug, effects of long-term exposure to cisplatin at the environmentally relevant concentrations on the crustacean health and its molecular mechanism remain undetermined. In this study, the growth and reproduction of Daphnia magna resulting from cisplatin exposure were initially assessed. While the phenotypes were not altered in 2 μg L^-1, 20 μg L^-1, and 200 μg L^-1 treatment groups, cisplatin at 500 µg L^-1 significantly reduced the offspring number to 8-13 neonates in each brood, which was lower than 13-27 neonates in the control group. In addition to the delay in the time of first pregnancy, the body length was decreased by approximate 12.13% at day 7. Meanwhile, all daphnids died after exposure to 500 µg L^-1 cisplatin for 17 days. Transcriptome profiling bioassays were performed for 10 days to explore the alternation at the molecular level. Briefly, 980 (257 up- and 723 down-regulated), 429 (182 up- and 247 down-regulated) and 1984 (616 up-regulated and 1368 down-regulated) genes were differentially expressed (adj p < 0.05) in low (2 μg L^-1), medium (200 μg L^-1) and high (500 μg L^-1) cisplatin treatment groups, respectively. Differentially expressed genes were primarily enriched in the digestion and absorption, nerve conduction, endocrine interference, and circulatory related pathways. Specifically, the down-regulated digestive secretion and nutrient absorption and neuronal conduction pathways may lead to insufficient energy supply involved in growth and reproduction, and hinder ovarian development and cell growth. Down-regulation of ovarian steroids and relaxin signaling pathways may be related to the reduction of offspring number and delayed pregnancy, and reduced body length of D. magna may attribute to the enrichment of insulin secretion pathway. In addition, the death of D. magna may result from the reduced expression of genes in cardiomyocyte contraction and apoptosome processes. Taken together, this study revealed the potential toxic mechanism of cisplatin in a model water flea.

Cyclophosphamide alters the behaviors of adult Zebrafish via neurotransmitters and gut microbiota

Cyclophosphamide, one of the earliest prescribed alkylating anticancer drugs, has been frequently detected in aquatic environments. However, its effects on fish behavior and associated mechanisms remain largely unknown. In this study, the behaviors, neurochemicals, and gut microbiota of adult zebrafish were investigated after 2 months of exposure to CP at 0.05, 0.5, 5, and 50 µg/L. Behavioral assays revealed that CP increased locomotion and anxiety, and decreased the cognition of zebrafish. The alteration of neurotransmitters and related gene expressions in the dopamine and gamma-aminobutyric acid pathways induced by CP may be responsible for the observed changes in locomotion and cognition of adult zebrafish. Meanwhile, CP increased the anxiety of adult zebrafish through the serotonin, acetylcholine, and histamine pathways in the brain. In addition, increased abundances of Fusobacteriales, Reyanellales, Staphylococcales, Rhodobacterals, and Patescibateria in the intestine at the CP-50 treatment were observed. The study has demonstrated that CP affects the locomotion, anxiety, and cognition in zebrafish, which might be linked with the dysfunction of neurochemicals in the brain. This study further suggests that the gut-brain axis might interact to modulate fish behaviors upon exposure to CP (maybe other organic pollutants). Further research is warranted to test this hypothesis.

Evaluation of uptake of the cytostatic methotrexate in Elliptio complanata mussels by LC-MS/MS

Aquatic organisms are continuously exposed to emerging contaminants coming from urban effluents of wastewater treatment plants. The contamination of surface water by those effluents poses a number of environmental risks, and pharmaceuticals are part of this class of effluent contaminants. Various classes of pharmaceuticals are not treated by wastewater treatment plants and anticancer drugs are part of them. The chemotherapy drug methotrexate (MTX) is an emerging contaminant and its growing use with the increase in cancer cases worldwide raises potential risk to aquatic organisms exposed to effluent discharges. However, chemical analyses in exposed freshwater aquatic organisms for ecotoxicological studies are rarely available and no studies have been done yet to accompany ecotoxicological data of exposed filter-feeding organisms. The purpose of this study was to develop a specific and sensitive analytical LC-MS/MS method for the quantification of methotrexate uptake in mussels exposed at different concentrations of the drug. A solid/liquid extraction followed by solid phase extraction (SPE) using an MCX phase purification scheme was optimized. The optimal recovery of 65% and matrix effect of 38% allowed to achieve a limit of quantification of 0.25 ng g^-1, with an accuracy of 99-106%, a precision of no more than 3% RSD, and linearity ranging from 0.25 to 25 ng g^-1. This methodology was tested with mussels exposed for 96 h at different concentrations (4 to 100 µg L^-1) of MTX. The data revealed tissue uptake at concentrations ranging from 0 to 2.53 ng g^-1. This suggests that this drug has low uptake potential and this methodology could be used to examine tissue levels of this drug in organisms continuously exposed to urban pollution.

The effects of the chemotherapy drug cyclophosphamide on the structure and functioning of freshwater communities under sub-tropical conditions: A mesocosm study

Cyclophosphamide (CP) is a chemotherapy drug which is widely used in the treatment of neoplastic diseases and have often been detected in urban and hospital wastewater, and surface waters. However, at present the effects of CP on aquatic organisms and ecosystems are poorly understood. The main objective of the present study was to assess the effect of CP on the structure and functioning of a sub-tropical freshwater ecosystem (macroinvertebrates, zooplankton and phytoplankton) at environmental relevant concentrations. CP (0, 0.5, 5 and 50 μg/L) was applied weekly to 13,600 L mesocosms over a period of four weeks followed by a one month post exposure period. CP was found to dissipate much faster than previous reported in literature and the half-dissipation times were treatment dependent, being 2.2, 21.3 and 23.6 days in the lowest, middle and highest treatments respectively. Only treatment related effects were observed on the community structure at individual samplings with zooplankton (NOEC_community = 0.5 μg/L) responding at lower concentrations than phytoplankton (NOEC_community = 5 μg/L) and macroinvertebrates (NOEC_community ≥ 50 μg/L). The dissolved organic carbon concentration was consistently higher in the 2 highest treatments, indicating a potential effect on food web interactions and/or the microbial loop. At the population level, consistent adverse effects were observed for the plankton taxa Pleuroxus laevis, Dissotrocha sp. and Oscillatoria sp. at all CP concentrations (NOEC <0.5 μg/L). Additionally, at the highest CP treatments 7% of all the taxa showed a clear short-term adverse effect. Based on comparison with literature data it can be concluded that these taxa have the highest CP sensitivity ever recorded and these findings indicate a potential CP risk to aquatic ecosystems at environmental relevant concentrations.

Cyclophosphamide affects eye development and locomotion in zebrafish (Danio rerio)

Cyclophosphamide (CP) is a broad-spectrum anticancer drug and has been frequently detected in aquatic environments due to its incomplete removal by wastewater treatment facilities and slow degradation in waters. Its toxicity in fish remains largely unknown. In this study, zebrafish eggs <4 h post fertilization (hpf) were exposed to CP at the concentrations from 0.5 to 50.0 μg/L until 168 hpf, and its toxicity was evaluated by biochemical, transcriptomic, and behavioral approaches. The results showed that malformation and mortality rates increased with CP concentrations. The 7-day malformation EC₅₀ and mortality (LC₃₀) by CP were calculated to be 86.8 μg/L and 7.5 mg/L, respectively. Inhibited startle response (light to dark) (a minimal of 19%) and reduced swimming velocity (a minimal of 30%) were observed in the CP-exposed larvae. The thicknesses of retinal ganglion layer, inner plexiform layer, and inner nuclear layer in the retina were increased after exposure to CP. Meanwhile, exposure to CP increased karyorrhexis and karyolysis in the liver tissue. Transcriptomic analysis identified 607 differentially expressed genes (DEGs) (159 up-regulated and 448 down-regulated). A significant reduction in the transcripts of sgk1 (the FoxO pathway), jun (the MAPK pathway), and diabloa (apoptosis pathway) were observed in the CP-treated larvae. This study has demonstrated that low concentrations of CP cause malformation, reduced swimming capacity, histopathological alterations in the retina and liver tissues, and interference on transcriptional expressions of key genes associated with different pathways. The ecological risk of CP and other anticancer drugs to aquatic organisms merits future investigation.

Remediation of pharmaceuticals from contaminated water by molecularly imprinted polymers: a review

The release of pharmaceuticals into the environment induces adverse effects on the metabolism of humans and other living species, calling for advanced remediation methods. Conventional removal methods are often non-selective and cause secondary contamination. These issues may be partly solved by the use of recently-developped adsorbents such as molecularly imprinted polymers. Here we review the synthesis and application of molecularly imprinted polymers for removing pharmaceuticals in water. Molecularly imprinted polymers are synthesized via several multiple-step polymerization methods. Molecularly imprinted polymers are potent adsorbents at the laboratory scale, yet their efficiency is limited by template leakage and polymer quality. Adsorption performance of multi-templated molecularly imprinted polymers depends on the design of wastewater treatment plants, pharmaceutical consumption patterns and the population serviced by these wastewater treatment plants.

Photodegradation of methotrexate in aqueous solution: degradation kinetics and identification of transformation products

Methotrexate is an antineoplastic folate analog of high environmental concern, due to its low biodegradability and toxicological properties. This study focused on its photodegradation under two irradiation conditions, aiming to be representative of environment (300-450 nm) and drinking water treatment (254 nm). The photodegradation experiments were conducted at two pH, to vary the methotrexate ionization state and to produce a large variety of transformation products (TPs). The degradation kinetics determined through LC-UV monitoring were contrasted according to pH and irradiation wavelength. However, the quantum yields were independent of ionization state at 254 nm and the changes in kinetics at higher wavelengths were attributed to a change in the degradation mechanism. The TPs formed during the reactions were identified by UHPLC-MS/MS, using both the positive and negative modes. Among the eleven proposed structures, five were described as methotrexate TPs for the first time. The TPs result from N-demethylation, glutamic acid oxidation, and C-N cleavage, all of them leading to further degraded photoproducts presenting modified or lost glutamic acid part. This was made possible thanks to the negative mode, which allowed the exploration of the glutamic acid moiety modifications. Cytotoxicity assessment on A549 cancer cells demonstrated that all photoproducts formed at pH 7 were less toxic than the parent compound.

Aquatic ecotoxicology of anticancer drugs: A systematic review

Anticancer drugs in the aquatic environment have drawn a lot of attention in the last decade. Since wastewater treatment plants are inefficient at fully eliminating trace concentrations of anticancer drugs, these compounds are continuously discharged into the aquatic environment. Subsequently, non-target organisms such as the aquatic biota are directly exposed to a variety of anticancer drugs. To understand the potential impact on the aquatic organisms, a systematic review was conducted in compliance with the PRISMA guidelines. The results acquired from the 152 included studies were analysed and sorted into four categories: the impact of each included anticancer drug, the effect of metabolites, the effect of a mixture of drugs, and risk assessment. Findings showed that risk to the aquatic biota was unlikely to occur as the concentrations needed to induce effects were much higher than those detected in the environment. However, these data were based on acute toxicity and included only basic toxicity endpoints. The concentrations that produced significant effects were much lower when tested in the long-term or in multi-generational studies. Heterogeneity in results was also observed; this depended on the organism tested, the assessment adopted, and the endpoints selected. In this systematic review, an overall view of the research studies was generated by which all the variability factors to be considered were reported and recommendations to guide future studies were proposed.

Enhanced Efficiency of the Removal of Cytostatic Anthracycline Drugs Using Immobilized Mycelium of Bjerkandera adusta CCBAS 930

The aim of this study was to evaluate the bioremoval of anthracycline antibiotics (daunomycin-DNR, doxorubicin-DOX, and mitoxantrone-MTX) by immobilized mycelium of B. adusta CCBAS 930. The activity of oxidoreductases: versatile peroxidases (VP), superoxide dismutase (SOD), catalase (CAT), and glucose oxidase (GOX), and the levels of phenolic compounds (PhC) and free radicals (SOR) were determined during the biotransformation of anthracyclines by B. adusta strain CCBAS 930. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (MARA assay), and genotoxicity of anthracyclines were evaluated after biological treatment. After 120 h, more than 90% of anthracyclines were removed by the immobilized mycelium of B. adusta CCBAS 930. The effective biotransformation of anthracyclines was correlated with detoxification and reduced genotoxicity.

The antineoplastic drugs cyclophosphamide and cisplatin in the aquatic environment - Review

Cyclophosphamide (CP) and Cisplatin (CDDP) are antineoplastic drugs widely used in the treatment of neoplastic diseases that have been detected in the aquatic environment. This review summarizes the current knowledge on the presence in the aquatic environment of these two drugs and their effects on freshwater and marine invertebrates, which includes good model species in ecotoxicology and risk assessment programs. The consumption levels, occurrence in freshwater and marine ecosystems, and the impacts exerted on aquatic organisms, even at low concentrations, justifies this review and the selection of these two drugs. Both pharmaceuticals were detected in different aquatic environments, with concentrations ranging from ng L^-1 up to 687.0 μg L^-1 (CP) and 250 μg L^-1 (CDDP). The available studies showed that CP and CDDP induce individual and sub-individual impacts on aquatic invertebrate species. The most common effects reported were changes in the reproductive function, oxidative stress, genotoxicity, cytotoxicity and neurotoxicity. The literature used in this review supports the need to increase monitoring studies concerning the occurrence of antineoplastic drugs in the aquatic environment since negative effects have been reported even at trace concentrations (ng L^-1). Furthermore, marine ecosystems should be considered as a priority since less is known on the occurrence and effects of antineoplastic drugs in this environment comparing to freshwater ecosystems.

Removal of two cytostatic drugs: bleomycin and vincristine by white-rot fungi - a sorption study

PURPOSE

Cytostatic drugs cannot be easily removed by conventional sewage treatment plants, resulting in their ultimate release into aquatic systems where they become a threat. Thus, new technologies which can be used to eliminate these drugs more effectively before they enter the environment are increasingly important. Fungal treatment of wastewaters is a promising and environmentally friendly technology for pharmaceutical remediation. The aim of this work is to examine the biosorption of two cytostatics, bleomycin and vincristine, in the aqueous solution by fungal biomass.

METHODS

Five white-rot fungi were used in this study: Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH), and Trametes versicolor (CB8). Tests were conducted on different types of biomass (alive and dead - autoclaved) and in various physico-chemical conditions: varied drug concentrations (5, 10 and 15 mg/L), temperatures (from 15.4 to 29.6 °C), and pH (from 3.2 to 8.8).

RESULTS

The results showed that among alive biomass, T. versicolor (CB8) had the greatest sorption ability for bleomycin and P. nidulans (CB14) worked best for vincristine. The tested sorption process could be described by a pseudo-second order kinetics model. Sorption equilibrium studies demonstrated that for bleomycin Redlich-Peterson, while for vincristine Langmuir model fitted best. The thermodynamic studies showed that the sorption process was endothermic chemisorption for bleomycin, and exothermic physisorption for vincristine. For both drugs the sorption ability increased with an increase of the pH value.

CONCLUSION

The biosorption on fungal biomass is a favorable alternative to conventional wastewater treatment processes for anticancer drug removal.

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).

Possibility to Biotransform Anthracyclines by Peroxidases Produced by Bjerkandera adusta CCBAS 930 with Reduction of Geno- and Cytotoxicity and Pro-Oxidative Activity

The aim of this study was to evaluate the bioremoval mechanism of anthracycline antibiotics by the white-rot fungus B. adusta CCBAS 930. The activity of oxidoreductases and levels of phenolic compounds and free radicals were determined during the biotransformation of anthraquinone antibiotics: daunomycin (DNR) and doxorubicin (DOX) by B. adusta strain CCBAS 930. Moreover, phytotoxicity (Lepidium sativum L.), ecotoxicity (Vibrio fischeri), genotoxicity and cytotoxicity of anthraquinone dyes were evaluated before and after biological treatment. More than 80% and 90% of DNR and DOX were removed by biodegradation (decolorization). Initial solutions of DNR and DOX were characterized by eco-, phyto-, geno- and cytotoxicity. Despite efficient decolorization, secondary metabolites, toxic to bacteria, formed during biotransformation of anthracycline antibiotics in B. adusta CCBAS 930 cultures. DNR and DOX metabolites did not increase reactive oxygen species (ROS) production in human fibroblasts and resazurin reduction. DNR metabolites did not change caspase-3 activity.

Threat and sustainable technological solution for antineoplastic drugs pollution: Review on a persisting global issue

In the past 20 years, the discharge of pharmaceuticals and their presence in the aquatic environment have been continuously increasing and this has caused serious public health and environmental concerns. Antineoplastic drugs are used in chemotherapy, in large quantities worldwide, for the treatment of continuously increasing cancer cases. Antineoplastic drugs also contaminate water sources and possess mutagenic, cytostatic and eco-toxicological effects on microorganisms present in the aquatic environment as well as on human health. Due to the recalcitrant nature of antineoplastic drugs, the commonly used wastewater treatment processes are not able to eliminate these drugs. Globally, various anticancer drugs are being consumed during chemotherapy in hospitals and households by out-patients. These anti-cancer agents enter the water bodies in their original form or as metabolites via urine and faeces of the out-patients or the patients admitted in hospitals. Due to its high lipid solubility, the antineoplastic drugs accumulate in the fatty tissues of the organisms. These drugs enter through the food chain and cause adverse health effects on humans due to their cytotoxic and genotoxic properties. The United States Environmental Protection Agency (US-EPA) and the Organization for Economic Cooperation and Development (OECD) elucidated new regulations for the management of hazardous pharmaceuticals in the water environment. In this paper, the role of antineoplastic agents as emerging water contaminants, its transfer through the food chain, its eco-toxicological properties and effects, technological solutions and management aspects were reviewed.

Detection of anti-cancer drugs and metabolites in the effluents from a large Brazilian cancer hospital and an evaluation of ecotoxicology

The use of chemotherapy agents has been growing worldwide, due to the increase number of cancer cases. In several countries, mainly in Europe countries, these drugs have been detected in hospitals and municipal wastewaters. In Brazil this issue is poorly explored. The main goal of this study was to assess the presence of three anti-cancer drugs, 5-fluorouracil (5-FU), gemcitabine (GEM) and cyclophosphamide (CP), and two metabolites, alpha-fluoro-beta-alanine (3-NH₂-F) and 2'-deoxy-2',2'-difluorouridine (2-DOH-DiF), in effluents from a large cancer hospital, in the municipal wastewater treatment plant (WWTP) influent and effluent, and also to evaluate toxicity of the mixtures of these compounds by ecotoxicological testing in zebrafish. The sample collections were performed in Barretos Cancer Hospital of the large cancer center in Brazil. After each collection, the samples were filtered for subsequent Liquid Chromatography Mass Spectrometry analysis. The presence of CP, GEM, and both metabolites (3-NH₂-F and 2-DOH-DiF) were detected in the hospital wastewater and the WWTP influent. Three drugs, GEM, 2-DOH-DiF and CP, were detected in the WWTP effluent. Two drugs were detected below the limit of quantification, 2-DOH-DiF: <LOQ (above 1400 ng L^-1) and CP: <LOQ (above 300 ng L^-1), and GEM was quantified at 420 ng L^-1. Furthermore, 2-DOH-DiF (116,000 ng L^-1) was detected at the highest level in the hospital wastewater. There were no zebrafish deaths at any of the concentrations of the compounds used. However, we observed histological changes, including aneurysms and edema in the gills and areas of necrosis of the liver. In summary, we found higher concentrations of CP, GEM and both metabolites (3-NH₂-F and 2-DOH-DiF) were detected for the first time. There is currently no legislation regarding the discharge of anti-cancer drugs in effluents in Brazil. This study is first to focus on effluents from specific treatments from a large cancer hospital located in small city in Brazil.

Ecotoxicological assessment of chemotherapeutic agents using toxicity tests with embryos of Mellita quinquiesperforata

The consumption of anticancer agents has increased in the recent decades, and these substances may be present in sewage. Consequently, they may reach the environment when sanitation infrastructure is ineffective. This study evaluated the toxicity of three anticancer agents-Tamoxifen (TAM), Cisplatin (CisPt), and Cyclophosphamide (CP)-on the development of embryos of the sand-dollar Mellita quinquiesperforata. Adult individuals were collected in sandy beaches, and gametes were obtained. Freshly-fertilized eggs were exposed to increasing sets of concentrations of each compound, and the effective concentrations needed to cause a 50% effect in the organisms (EC50) were calculated. The three compounds were toxic, and their EC50 values were 16.78 ± 2.42 ng·L^-1 (TAM), 27.20 ± 38.26 ng·L^-1 (CisPt), and 101.82 ± 70.96 ng·L^-1 (CP). There is no information on the environmental levels of these compounds in Brazil, but as they were already detected in ng·L^-1 levels worldwide, it can be expected that these substances pose environmental risks to the marine biota.

Green-photodegradation of model pharmaceutical contaminations over biogenic Fe3O4/Au nanocomposite and antimicrobial activity

A simple biogenic approach for synthesis of Fe₃O₄/Au nanocomposite with 31 nm size using aqueous extract of Carum carvi L. seeds has been reported. Phytochemicals of Carum carvi L. seeds extract play three roles, including reducing, capping, and stabilizing agents during the nanocomposite fabrication process. Resulting nanocomposite was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, differential reflectance spectroscopy, vibrating-sample magnetometer, energy-dispersive X-ray spectroscopy and X-ray elemental mapping. Differential reflectance spectroscopy investigated optical property and absorption spectra display a sharp absorption agreeing to a bandgap of 1.6 eV. Photocatalytic activity of biogenic Fe₃O₄/Au nanocomposite has been investigated for degradation of imatinib and imipenem drugs under UV and visible light irradiation, due to pharmaceuticals have shown to be recalcitrant in wastewater and conventional wastewater treatments do not remove them, often. Degradation efficiency of imatinib, and imipenem are about 92% and 96% after 1200 s exposure UV light and about 82% and 84% after 3600s exposure visible light in the concentration of 10 ppm drugs. Also, antimicrobial activity of biogenic Fe₃O₄/Au nanocomposite was investigated on three human pathogens and best result can see in 25 mg/mL of nanocomposite versuse Bacillus subtilis that inhibition zone is about 27 mm. Design of nanocomposites capable of simultaneously removing pharmaceutical and microbial contaminations is important in environments such as hospitals wastewater treatment.

In Vitro Cytotoxicity Study of Cyclophosphamide, Etoposide and Paclitaxel on Monocyte Macrophage Cell Line Raw 264.7

The presence of antineoplastic compounds in aquatic ecosystem is an emerging challenge for the society. Antineoplastic compounds released into the aquatic environment exhibit a potential threat to normal aquatic life. Particularly, antineoplastic compounds are responsible for direct or indirect interference with the cellular DNA of an organism and cause toxicity to cells. The present study focused on the assessment of in vitro toxic effect of cyclophosphamide, etoposide and paclitaxel on Raw 264.7 cell line (mouse monocyte macrophage cells). The inhibitory concentration of cyclophosphamide, etoposide, and paclitaxel was determined. The IC₅₀ values of these compounds were 145.44, 5.40, and 69.76 µg ml^-1 respectively. This is the first report on toxicity analysis of cyclophosphamide, paclitaxel and etoposide on Raw 264.7 cell line by reducing cell viability and indicating the cell cytotoxicity i.e., 69.58% for cyclophosphamide, 92.01% for etoposide and 88.85% for paclitaxel on concentration 250 µg ml^-1. The results of their cytotoxicity assessment highlight the need of improvement in sewage treatment technology for the efficient removal of these compounds from aquatic environment.

Evaluation of toxic effects of platinum-based antineoplastic drugs (cisplatin, carboplatin and oxaliplatin) on green alga Chlorella vulgaris

Platinum-based antineoplastic drugs (PBADs) enter the environment via hospital and municipal wastes as reactive and highly toxic molecules. Chlorella vulgaris is a freshwater microalgae and is used as an excellent aquatic model for toxicity assessment. In the present study, the toxicity of PBADs to C. vulgaris was investigated for better understanding of PBADs environmental toxicity. The algae were cultured in Bold´s Basal Medium (BBM) and exposed to different concentrations of PBADs for 48, 72 and 96 h. Then, cell proliferation, the synthesis of photosynthetic pigments, protein content, malondialdehyde (MDA) release and antioxidant potential were determined. IC₅₀ s of cisplatin, carboplatin and oxaliplatin for 96 h of exposure were 106.2, 124.3 and 153.9 mg/L respectively. Cell proliferation, synthesis of chlorophyll a, chlorophyll b and algal protein content significantly decreased in a time and dose-dependent manner. The release of MDA to culture media significantly increased and antioxidant potential decreased. Cisplatin showed more toxic effects on C. vulgaris compared to carboplatin and oxaliplatin indicating its severe toxicity for marine organisms. PBADs induce their toxic effects in algal cells via the interaction with DNA, production of free radicals (such as reactive oxygen species), lipid peroxidation and cell wall damages. Due to these toxic effects of PBADs for various environmental organisms, there must be severe restriction on their release into the environment.

Determination of 5-fluorocytosine, 5-fluorouracil, and 5-fluorouridine in hospital wastewater by liquid chromatography-mass spectrometry

Chemotherapeutics are pharmaceutical compounds the occurrence of which in the environment is of growing concern because of the increase in treatments against cancer diseases. They can reach the aquatic ecosystems after passing through wastewater treatment plants without complete removal. One of the most frequently used chemotherapeutics is 5-fluorouracil which exhibits a strong cytostatic effect. In this paper, an analytical methodology was developed, validated, and applied to determine 5-fluorouracil, its precursor, 5-fluorocytosine, and its major active metabolite, 5-fluorouridine, in hospital wastewater samples. Due to the expected low concentrations after dilution and interferences present in such a complex matrix, a very selective and sensitive detection method is required. Moreover, an extraction method must be implemented prior to the determination in order to purify the sample extract and preconcentrate the target analytes at micrograms per liter concentration levels. Solid-phase extraction followed by liquid chromatography with tandem mass spectrometry was the combination of choice and all included parameters were studied. Under optimized conditions for wastewater samples analysis, recoveries from 63 to 108% were obtained, while intraday and interday relative standard deviations never exceeded 20 and 25%, respectively. Limits of detection between 61 and 620 ng/L were achieved. Finally, the optimized method was applied to samples from hospital wastewater effluents.

Cisplatin affects locomotor activity and physiological endpoints of Daphnia magna

Cisplatin (CPL) is a common antineoplastic drug used in human medicine for treatment of various cancer types. Since the knowledge about its effects on crustacean behavioral and physiological parameters is very scarce, the aim of our study was to determine the influence of CPL at concentrations of 125 μg/L, 200 μg/L, 500 μg/L and 1000 μg/L on swimming behavior (swimming speed, distance travelled, hopping frequency, propelling efficiency index - a novel parameter) and physiological parameters (heart rate, thoracic limb activity) of Daphnia magna with the use of video digital analysis. The results showed that distance travelled, swimming speed, hopping frequency and propelling efficiency were inhibited as early as after 24 h in concentration- and time-dependent manner. On the other hand, heart rate was stimulated in the animals treated with 125 μg/L of CPL after 48 h, 72 h and 120 h of the exposure, however it was decreased at the higher concentrations. Although thoracic limb activity was considerably increased in daphnids exposed to 125 μg/L and 200 μg/L after 72 h, it was inhibited at the higher concentrations of the drug. The study suggests that since CPL affected daphnid parameters at the environmental concentration, it should be considered as hazardous to zooplankton.

New insights on cytostatic drug risk assessment in aquatic environments based on measured concentrations in surface waters

Cytostatic drugs are compounds used to treat cancer, one of the deadliest diseases worldwide with a rising yearly incidence. However, the occurrence and concentrations of a large number of cytostatics in waters and wastewaters are unknown. Thus, this study sought to analyze the concentrations of these compounds in different aquatic environments worldwide to assess the risk that these compounds pose to aquatic organisms. The top five most monitored cytostatics in aquatic environments are fluorouracil, methotrexate, tamoxifen, ifosfamide, and cyclophosphamide. Risk quotients (RQs) based on maximum reported measured concentrations revealed that mycophenolic acid and tamoxifen pose a high risk to aquatic organisms (RQ_max ≥ 1) at concentrations observed in surface waters. Moreover, methotrexate and tegafur were categorized as moderate risk compounds, and bicalutamide was found to pose a low risk. Importantly, the available analytical methodologies for the quantification of some cytostatics (e.g., cisplatin, fluorouracil, daunorubicin, imatinib, and mycophenolic acid) in water could not rule out potential risk to aquatic biota, since estimated risks for these compounds using the lowest method detection limits reported in the literature (RQ MDL) were all ≥0.01 (i.e., low risk or higher). Moreover, risks based on predicted concentrations (RQ PEC) were consistently lower than those based on measured concentrations, highlighting the importance of risk assessment based on measured values. Thus, accurate and sensitive analytical methods are crucial to identify and quantify cytostatic exposure in aquatic ecosystems in order to preserve biodiversity and ensure a safer environment.

Photocatalytic degradation of cyclophosphamide and ifosfamide: Effects of wastewater matrix, transformation products and in silico toxicity prediction

Antineoplastic drugs have been identified in surface water and effluents from wastewater treatment and, once in the environment, may be harmful to aquatic organisms, as these compounds are possibly mutagenic, genotoxic, cytotoxic, carcinogenic and teratogenic. This work investigated the photodegradation of cyclophosphamide (CP) and ifosfamide (IF) using ruthenium doped titanate nanowires (Ru-TNW) in distilled water (DW) and in wastewater (WW) from secondary wastewater treatment, under UV-Vis radiation. The results indicated that Ru-TNW showed photocatalytic activity for the two cytotoxic drugs with the half-life (t_1/2) of 15.1 min for CP and 12.9 min for IF in WW. Four CP transformation products (TPs) and six IF TPs from the photodegradation process are here reported. These TPs were elucidated by high-resolution mass spectrometry. For both pollutants, the results showed different time profiles for the TPs when WW and DW were used as matrix. Overall, in the WW there was a higher production of TPs and two of them were detected only in this matrix. In other words, environmental matrices may produce different TPs. Degradation pathways were proposed and both drugs bear similarities. Additionally, in silico toxicity were performed by quantitative structure-activity relationship models. The predictions indicated that the TPs, with the exception of one IF TP, presented high mutagenic potential.

Cytostatic pharmaceuticals as water contaminants

Due to the growing problem of cancer diseases, cytostatic drugs have become a great environmental threat. Their main sources are hospital effluents, household discharge and drug manufacturers. As these compounds are not removed during wastewater treatment with sufficient efficiency, they are found in the surface, ground and drinking water in quantities up to 2.12 × 10^-4 mg/l. The current knowledge about their harmful influence on humans does not indicate a significant risk to the health of water consumers, although it points to certain groups of risk (children and lactating women) in particular. In aquatic organisms, anticancer drugs in detected concentrations can cause chronic toxicity and have a detrimental impact on their genetic material. The acute toxicity effect is less likely. The HC₅ value calculated by us (the concentration at which 5% of the species is potentially affected) equalling 2.1 × 10^-4 mg/l shows that anticancer drugs are real hazardous contaminants for the environment. It indicates that effective elimination of cytostatics from water still requires intensive research.

Environmental risk assessment of widely used anticancer drugs (5-fluorouracil, cisplatin, etoposide, imatinib mesylate)

Anticancer drugs are among the most toxic chemicals, which are commercially produced; therefore, their release in aquatic ecosystems raised concerns in regard to potential adverse effects. This article describes the results of risk assessments concerning their environmental safety, which are based on data generated in the frame of a coordinated EU project ("Cytothreat"). Eight research institutions participated in the project and four widely used anticancer drugs with different mechanisms of therapeutic action (5-fluorouracil 5FU, cisplatin CDDP, imatinib mesylate IM and etoposide ET) were tested in a variety of indicator organisms (cyanobacteria, algae, higher plants, rotifers, crustacea, fish and also in human and fish derived cell lines) in acute/subacute/chronic toxicity assays. Furthermore, genotoxic effects in micronucleus assays, single cell gel electrophoresis experiments and γH2AX tests were studied in plants, crustacea, fish and in various cell lines. We used the results to calculate the predicted no effect concentrations (PNEC) and risk quotients (RQ) by comparing PNEC with predicted environmental concentrations (PEC values) and measured concentrations (MEC) in wastewaters. The most sensitive species in experiments concerning acute toxic and long term effects were in general crustacea (daphnids) after chronic treatment the most pronounced effects were detected with IM followed by CDDP and 5FU. Comparisons between PNEC and PEC values indicate that it is unlikely that the release of these drugs in the aquatic environments leads to adverse effects (RQ values < 1). However, when the assessments were performed with MEC found in highly contaminated municipal wastewaters and hospital effluents, RQ values were obtained which are indicative for moderate adverse effects of IM. Calculations with data from genotoxicity experiments and PEC values are indicative for increased RQ values for all compounds except ET. The most sensitive species were fish (Danio rerio) which were highly responsive towards 5FU and daphnids which were sensitive towards CDDP and IM. When environmental data (from waste waters) were used for the calculations, high RQ values (>100) were obtained for CDDP and IM. These overall conclusions were not substantially altered when the effects of other frequently used cytostatic drugs and combined effects of mixtures of anticancer drugs were taken into consideration. The results of these assessments underline the importance of efficient removal of these chemicals by improved sewage treatment strategies and the need for further investigations of adverse the long term effects of cytostatics in aquatic biota as a consequence of damage of the genetic material in highly sensitive species.

Effects of mixtures of anticancer drugs in the benthic polychaete Nereis diversicolor

The increasing consumption of anticancer drugs through single and/or combinatory chemotherapy worldwide raised concern regarding their toxicity burden in coastal zones. The toxicity of a mixture of three compounds involving the drugs cisplatin (CisPt), cyclophosphamide (CP) and tamoxifen (TAM) was determined on the marine polychaete Nereis diversicolor exposed to an increasing range of their concentrations, respectively: Mix A: 0.1 + 10 + 0.1 ng L^-1; Mix B: 10 + 100 + 10 ng L^-1; Mix C: 100 + 500 + 25 ng L^-1; Mix D: 100 + 1000 + 100 ng L^-1. Different endpoints were assessed, including disturbance in the burrowing behaviour, neurotoxicity (acetylcholinesterase - AChE activity), antioxidant enzymes (superoxide dismutase - SOD; catalase - CAT; selenium-dependent glutathione peroxidase - Se-GPx and total glutathione peroxidases T-GPx activities), biotransformation metabolism (glutathione-S-transferases - GST), lipid peroxidation (LPO) and genotoxicity (DNA damage). Biological effects of the mixtures of anticancer compounds on N. diversicolor were compared with previous studies about effects on the same biological model under single-drug exposure conducted with the same molecules. Regarding SOD activity, TAM showed an antagonist effect over CisPt and CP in mixtures C and D. In Mix D, there was a synergistic effect of TAM and CisPt that inhibited CAT activity and an additive interaction of CisPt and CP on the Phase II biotransformation enzyme. Drugs in Mix A also suppressed polychaetes' GST activity, although different from the respective single-drug responses, besides able to induce T-GPx activity, that was not sufficient to avoid oxidative damage and mid-grade DNA damage. Due to the absence of burrowing impairment in Mix A, mechanisms involved in neurotoxicity were other than the one driven by AChE alterations. At the intermediary concentrations (Mix B and C), only LPO occurred. Data from drugs individually may not predict the risks provided by mixtures.

Ecotoxicity risk of presence of two cytostatic drugs: Bleomycin and vincristine and their binary mixture in aquatic environment

Cytostatic drugs have become one of the greatest environmental threats. They occur in surface, ground and even drinking water. Their key emission sources are hospital effluents, municipal wastewater, as well as drug manufacturers and their effluents. These compounds are extremely stable in natural waters and they are not significantly removed during wastewater treatment, because they are resistant to biodegradation. The aim of this work was to establish possible negative effects of chosen cytostatics: bleomycin and vincristine on the three trophic levels of surface waters. A single agent acute toxicity test was conducted on representatives of the producer - an aquatic freshwater plant Lemna minor, the consumer - crustaceans Daphnia magna, and the decomposer - bacteria Pseudomonas putida. Binary mixture tests were performed according to the Concentration Addition, Response Additivity, and Independent Action models. Both substances had a different effect on the tested organisms; bleomycin could be classified as a very toxic, while vincristine as a toxic water pollutant. Half maximal effective concentration (EC50) values designed in the presented single agent acute toxicity studies are < 10 mg/L in all the tests with bleomycin as well as vincristine conducted on L. minor. In tests with vincristine performed on D. magna and P. putida EC50 > 100 mg/L. The highest toxicity is demonstrated by bleomycin towards the aquatic freshwater plant (EC50 = 0.2 mg/L). The binary mixture of the tested chemicals showed antagonistic effects of environmental concern.

Environmental relevant levels of the cytotoxic drug cyclophosphamide produce harmful effects in the polychaete Nereis diversicolor

Cytotoxic drugs applied in chemotherapy enter the aquatic environment after patient's metabolism and excretion, in both main compounds and their respective metabolites. The increased consumption and discharge of these drugs raise concern on the genotoxic burden to non-target aquatic species, due to their unselective action on DNA. Settlement and adsorption of cytotoxic drugs to aquatic sediments pose risks to benthic species through chronic exposure. The aim of the present study was to assess the effects induced by the anticancer drug cyclophosphamide (CP) on the polychaete Nereis diversicolor, after 14 days of exposure to environmental relevant concentrations (10, 100, 500 and 1000 ng L^-1). Burrowing impairment, neurotoxicity (Acetylcholinesterase - AChE activity), oxidative stress (superoxide dismutase - SOD; catalase - CAT; glutathione peroxidases - GPXs activities), biotransformation (glutathione-S-transferases - GST), oxidative damage (lipid peroxidation - LPO) and genotoxicity (DNA damage) were assessed. Burrowing impairments were higher at the lowest CP concentrations tested. The higher CP levels tested (500 and 1000 ng L^-1) induced a significant inhibition on the enzymatic antioxidant system (SOD, GPx) and on GST activity. DNA damage was also significant at these concentrations as an outcome of CP metabolism, and high levels of oxidative damage occurred. The results showed that the prodrug CP was metabolically activated in the benthic biological model N. diversicolor. In addition to the potential cytotoxic impact likely to be caused in aquatic species with similar metabolism, N. diversicolor proved to be reliable and vulnerable to the cytotoxic mode of action of CP, even at the lower doses.

Chlorination of 5-fluorouracil: Reaction mechanism and ecotoxicity assessment of chlorinated products

What happens to drugs in the chlorinating environment? Degradation products may vary in pharmacological profiles and in ecotoxicity potentials compared to the parent compound. This study combines synthesis, NMR spectroscopy, quantum chemical calculations, and toxicity experiments on Daphnia magna to investigate chemical fate of antineoplastic drug 5-fluorouracil (5-FU) in chlorinated environment, which is common in waste-water treatment procedures, but also endogenous in activated neutrophils. A reduction of toxicity (EC₅₀ after 48 h is 50% higher than for the parent 5-FU) was observed after the first chlorination step, in which a chlorohydrin 5-chloro-5-fluoro-6-hydroxy-5,6-dihydrouracil was formed. Further chlorination leads to N-chlorinated intermediate, that undergoes the pyrimidine ring opening reaction. The final product, 2-chloro-2-fluoro-3,3-dihydroxypropanoic acid was obtained after the loss of the chlorinated urea fragment. This is the most potent compound in the reaction sequence, with toxicity parameter EC₅₀, after 48 h, more than twice lower compared to the parent 5-FU. Clearly, the contact time between chlorinating species and degradation products provide different ecotoxicological properties of reaction mixtures. Interplay between experimental and theoretical procedures, to properly describe reaction pathways and provide more information on toxicity profiles, is a way forward in environmental science research.

Yeast-based genotoxicity tests for assessing DNA alterations and DNA stress responses: a 40-year overview

By damaging DNA molecules, genotoxicants cause genetic mutations and also increase human susceptibility to cancers and genetic diseases. Over the past four decades, several assays have been developed in the budding yeast Saccharomyces cerevisiae to screen potential genotoxic substances and provide alternatives to animal-based genotoxicity tests. These yeast-based genotoxicity tests are either DNA alteration-based or DNA stress-response reporter-based. The former, which came first, were developed from the genetic studies conducted on various types of DNA alterations in yeast cells. Despite their limited throughput capabilities, some of these tests have been used as short-term genotoxicity tests in addition to bacteria- or mammalian cell-based tests. In contrast, the latter tests are based on the emergent transcriptional induction of DNA repair-related genes via activation of the DNA damage checkpoint kinase cascade triggered by DNA damage. Some of these reporter assays have been linked to DNA damage-responsive promoters to assess chemical carcinogenicity and ecotoxicity in environmental samples. Yeast-mediated genotoxicity tests are being continuously improved by increasing the permeability of yeast cell walls, by the ectopic expression of mammalian cytochrome P450 systems, by the use of DNA repair-deficient host strains, and by integrating them into high-throughput formats or microfluidic devices. Notably, yeast-based reporter assays linked with the newer toxicogenomic approaches are becoming powerful short-term genotoxicity tests for large numbers of compounds. These tests can also be used to detect polluted environmental samples, and as effective screening tools during anticancer drug development.

Stropharia rugosoannulata and Gymnopilus luteofolius: Promising fungal species for pharmaceutical biodegradation in contaminated water

Pharmaceuticals are environmental micropollutants that pose an emerging challenge because they are poorly eliminated in conventional wastewater treatment plants. Over the last decade, many attempts have been made to solve this problem, and wastewater fungal treatment is a promising alternative. In this study, six different ligninolytic fungi (Trametes versicolor, Ganoderma lucidum, Irpex lacteus, Stropharia rugosoannulata, Gymnopilus luteofolius and Agrocybe erebia) were studied as bioremediation candidates for the removal and degradation of six recalcitrant pharmaceutical micropollutants: Carbamazepine (CBZ), Venlafaxine (VFX), Iopromide (IPD), Diclofenac (DCF), Cyclophosphamide (CFD) and Ifosfamide (IFD). Self-immobilization in a pellet shape was achieved for all fungal mycelia (which was the first time that this was reported for S. rugosoannulata, G. luteofolius, and A. erebia). Biodegradation achievement was greater than 90% for IPD with G. luteofolius and greater than 70% for CBZ with S. rugosoannulata, which suggests a great potential for this alternative biological treatment. Besides, this was the first report where fungal treatment achieved CFD and IFD removals greater than 20% for the treatment with T. versicolor, G. lucidum and S. rugosoannulata.

Evaluation of acute and chronic ecotoxicity of cyclophosphamide, ifosfamide, their metabolites/transformation products and UV treated samples

Cyclophosphamide (CP) and Ifosfamide (IF) are two nitrogen mustard drugs widely prescribed in cancer therapy. They are continuously released via excreta into hospital and urban wastewaters reaching wastewater treatment plants. Although CP and IF, their metabolites and transformation products (TPs) residues have been found in the aquatic environment from few ng L^-1 to tens of μg L^-1, their environmental toxic effects are still not well known. The present study aimed to investigate the acute and chronic ecotoxicity of CP and IF and their commercially available human metabolites/TPs, i.e. carboxy-CP, Keto-CP and N-dechloroethyl-CP on different organisms of the aquatic trophic chain. The experiments were performed using the green alga Pseudokirchneriella subcapitata, the rotifer Brachionus calyciflorus and the crustaceans Thamnocephalus platyurus and Ceriodaphnia dubia. Moreover, to assess the treatment conditions in regards to parent compound removal and formation of new TPs, CP and IF were UV- irradiated for 6 h, 12 h, 24 h, 36 h and 48 h, followed by toxicity evaluation of treated samples by algae, rotifers and crustaceans. Between the parent compounds, IF resulted as more toxic drug under tested conditions, exerting both acute and chronic effects especially on C. dubia (LC50:196.4 mg L^-1, EC50:15.84 mg L^-1). Among the tested metabolites/TPs, only carboxy-CP inhibited the reproduction in the rotifer. However, LOEC and NOEC values were calculated for CP and IF for all organisms. In addition, despite a low degradation of CP (28%) and IF (36%) after 48 h UV-irradiation, statistically significant effect differences (p < 0.05) from not-irradiated and irradiated samples were observed in both acute and chronic assays, starting from 6 h UV-irradiation. Our results suggest that the toxic effects found in the aquatic organisms may be attributable to interactions between the parent compounds and their metabolites/TPs.

A case study to identify priority cytostatic contaminants in hospital effluents

This study analyses the presence of 17 cytostatic agents from seven different groups, based on their different mechanisms of action, in the effluent from a medium-sized hospital located in eastern Spain. Analysis of the compounds found in the effluents studied involved solidphase extraction (SPE) coupled on-line to a high performance liquid chromatograph tandem mass spectrometer (HPLC-MS/MS). The environmental risk of the compounds studied was then assessed by calculating the hazard quotient (HQ), combining the measured environmental concentrations (MECs) with dose-response data based on the predicted no effect concentrations (PNECs). In addition, the environmental hazard associated was evaluated in accordance with their intrinsic characteristics by calculating the PBT (Persistence Bioaccumulation Toxicity) index. The results of this study showed the presence of seven of the 17 compounds analysed in a range of between 25 and 4761 ng/L. The highest concentrations corresponded to ifosfamide (58-4761 ng/L), methotrexate (394-4756 ng/L) and cyclophosphamide (46-3000 ng/L). Assessment of the environmental hazard showed that the three hormonal agents (tamoxifen and its metabolites endoxifen and hydroxytamoxifen) exhibited a maximum PBT value of 9 due to their inherent harm to the environment resulting from their characteristics of persistence, bioaccumulation and toxicity. A combined evaluation of the risk and environmental hazard showed that three of the 17 compounds studied, namely, ifosfamide, imatinib and irinotecan, all of which exhibited HQ values higher than 10 and PBT indices of 6, indicative of a particularly high potential to harm the environment, deserve special attention.

Cytotoxicity and genotoxicity of anticancer drug residues and their mixtures in experimental model with zebrafish liver cells

Anticancer drugs enter aquatic environment predominantly via hospital and municipal wastewater effluents where they may, due to their genotoxic potential, cause adverse environmental effects even at very low doses. In this study we evaluated cytotoxic and genotoxic potential of two widely used anticancer drugs, cyclophosphamide (CP) and ifosfamide (IF) as individual compounds and in a complex mixture together with 5-fluorouracil (5-FU) and cisplatin (CDDP) because these four drugs have been frequently detected in an oncological ward effluents. As an experimental model we used zebrafish liver cell (ZFL) line. The cytotoxicity was determined with the MTS assay and genotoxicity with the comet assay and cytokinesis block micronucleus (CBMN) assay that measure the formation of DNA strand breaks and genomic instability, respectively. CP and IF exerted low cytotoxicity towards ZFL cells. Both compounds induced DNA strand breaks and genomic instability, however at relatively high concentrations that are not relevant for the contamination of aquatic environment. The mixture of CP, IF, 5-FU and CDDP was tested at maximal detected concentrations of each drug as determined in the effluents from the oncological ward. The mixture was not cytotoxic and did not induce genomic instability, but it induced significant increase in the formation of DNA strand breaks at concentrations of individual compounds that were several orders of magnitude lower from those that were effective when tested as individual compounds. The results indicate that such mixtures of anticancer drugs may pose a threat to aquatic organisms at environmentally relevant concentrations and contribute to the accumulating evidence that it is not always possible to predict adverse effects of complex mixtures based on the toxicological data for individual compounds.

Acute aquatic toxicity assessment of six anti-cancer drugs and one metabolite using biotest battery - Biological effects and stability under test conditions

Available ecotoxicological data for anti-cancer drugs and their metabolites are incomplete, and only some studies have been accompanied by chemical analysis. Therefore, the main aim of this study was to evaluate the acute toxicity of the six most commonly used cytostatics, namely cyclophosphamide (CF), ifosfamide (IF), 5-fluorouracil (5-FU), imatinib (IMT), tamoxifen (TAM) and methotrexate (MET) and its metabolite - 7-hydroxymethotrexate (7-OH-MET), towards selected aquatic organisms, namely bacteria Vibrio fischeri, algae Raphidocelis subcapitata, crustaceans Daphnia magna and duckweed Lemna minor. All ecotoxicological tests were accompanied by chemical analysis to determine the differences between nominal and actual concentrations of investigated compounds and their stability under test conditions. For unstable compounds, tests were performed in static and semi-static conditions. It was observed that L. minor was the most sensitive organism. The compounds that were most toxic to aquatic organisms were 5-FU (highly toxic to algae, EC₅₀ = 0.075 mg L^-1), MET and TAM (very toxic to highly toxic to duckweed depending on the test conditions; EC_50MET 0.08-0.16 mg L^-1, EC_50TAM 0.18-0.23 mg L^-1). It is suspected that MET and 5-FU mainly affected algae and plants most probably because the exposure time was long enough for them to cause a specific effect (they inhibit DNA replication and act predominantly on actively dividing cells). Furthermore, the obtained results also suggest that the toxicity of the metabolites/potentially produced degradation products of MET towards duckweed is lower than that of the parent form, whereas the toxicity of TAM degradation products is in the same range as that of TAM.

Anticancer drugs in Portuguese surface waters - Estimation of concentrations and identification of potentially priority drugs

Anticancer drugs, used in chemotherapy, have emerged as new water contaminants due to their increasing consumption trends and poor elimination efficiency in conventional water treatment processes. As a result, anticancer drugs have been reported in surface and even drinking waters, posing the environment and human health at risk. However, the occurrence and distribution of anticancer drugs depend on the area studied and the hydrological dynamics, which determine the risk towards the environment. The main objective of the present study was to evaluate the risk of anticancer drugs in Portugal. This work includes an extensive analysis of the consumption trends of 171 anticancer drugs, sold or dispensed in Portugal between 2007 and 2015. The consumption data was processed aiming at the estimation of predicted environmental loads of anticancer drugs and 11 compounds were identified as potentially priority drugs based on an exposure-based approach (PEC_b> 10 ng L^-1 and/or PEC_c> 1 ng L^-1). In a national perspective, mycophenolic acid and mycophenolate mofetil are suspected to pose high risk to aquatic biota. Moderate and low risk was also associated to cyclophosphamide and bicalutamide exposition, respectively. Although no evidences of risk exist yet for the other anticancer drugs, concerns may be associated with long term effects.

Toxicological evaluation of the topoisomerase inhibitor, etoposide, in the model animal Caenorhabditis elegans and 3T3-L1 normal murine cells

Etoposide, a topoisomerase II inhibitor, has been widely used as a clinical anticancer drug to treat diverse cancer patients. Since not only rapidly dividing cancer cells but also the cells of normal human tissues and every living organism in environmental ecosystems have topoisomerases, it is crucial to study the toxicity of etoposide in other organisms in addition to cancer cells. In this study, we evaluated the toxicity of etoposide in both a soil nematode, Caenorhabditis elegans, and 3T3-L1 normal murine cells. Etoposide significantly retarded the growth, egg laying, and hatching in C. elegans. Etoposide also affected the reproductive gonad tissue, decreased the number of germ cells and induced abnormally enlarged nuclei in C. elegans. In addition, etoposide inhibited 3T3-L1 cell proliferation, with IC₅₀ values of 37.8 ± 7.3 and 9.8 ± 1.8 μM after 24 and 48 hours of treatment, respectively, via the induction of cell cycle arrest at the G2/M phase and apoptotic cell death. Etoposide also induced nuclear enlargement in 3T3-L1 normal murine cells. The reproductive toxicity and abnormal nuclear morphological changes seemed to correlate with the adverse effects of etoposide. We suggest that these experimental platforms, i.e., the toxicological evaluation of both nematodes and 3T3-L1 cells, may be useful to study the mechanisms underlying the side effects of chemicals, including topoisomerase inhibitors.

The role of bicarbonate anions in methotrexate degradation via UV/TiO2: Mechanisms, reactivity and increased toxicity

Bicarbonate anion (HCO₃^-) is a major constituent in wastewater and natural water matrices, and the aim of this study was to investigate its roles in the degradation of the antineoplastic agent methotrexate via UV/TiO₂. A comprehensive investigation of reaction mechanisms was performed by conducting scavenger experiments and substructure reactivity and Microtox^® toxicity tests. In the presence of HCO₃^-, the methotrexate degradation rate substantially increased, indicating the involvement of CO₃^-. The estimated second-order rate constants of methotrexate with CO₃^- and OH were 1.4 × 10⁷ M^-1 s^-1 and 8.7 × 10⁹ M^-1 s^-1, respectively. Both the valence hole (h_vb⁺) and OH resulted in the generation of CO₃^-. Initial transformation pathways of methotrexate were proposed, including the addition of atomic oxygen, hydroxylation, deamination, CC cleavage and CN cleavage. CN cleavage at the aniline moiety (the N(13) position) is the primary decomposition pathway, leading to an aminopterin yield of 43%. CO₃^- preferentially reacted with the 4-aminobenzamide (ABZ) moiety and generated toxic byproducts during the later stages of decomposition, which was not observed in the UV/TiO₂ system. The reactivity of the three methotrexate substructures decreased in the following order in the presence of HCO₃^-: ABZ ≫ DHP ≫ LG∼0; however, without HCO₃^-, the following order was observed: ABZ ∼ DHP > LG. The results of this work suggest that the increase in toxicity induced by the presence of HCO₃^- likely occurs in many other OH-based advanced oxidation processes in wastewater containing pharmaceutical cocktails with ABZ moieties.