Sorption of pharmaceuticals on the surface of microplastics.

The presence of both pollutants: microplastics and pharmaceutical residues in various environmental compartments is an issue of increasing concern. Available literature data indicates that microplastics can affect the environmental distribution and transport of e.g. persistent organic pollutants (POPs) through sorption interactions, concentrating them at a given point and thus influencing the environmental risks represented by the sorbent and sorbate pair. Therefore, their potential to change the fate of other contaminants in the environment, such as pharmaceuticals, is worth investigating. The aim of this study was to evaluate the sorption capacity of nine pharmaceuticals, commonly used in human and veterinary medicine, which constitute known ubiquitous water pollutants: enrofloxacin (ENR), ciprofloxacin (CIP), norfloxacin (NOR), 5-fluorouracil (5-FU), methotrexate (MET), flubendazole (FLU), fenbendazole (FEN), propranolol (PRO) and nadolol (NAD), on the surface of the most often identified microscopic plastic particles in the aquatic environment, i.e. polypropylene (PP), low density polyethylene (LD-PE), high density polyethylene (HD-PE) and polyvinyl chloride (PVC). The obtained results suggest a complex nature of sorption, including both hydrophobic and electrostatic interactions. However, since the ionic strength of the medium was found to be a significant factor influencing the sorption potential, minute interactions are observed in conditions common for the natural environment.

Bioaccumulation and analytics of pharmaceutical residues in the environment: A review.

The presence of pharmaceutical residues in various environmental compartments is an issue of increasing concern. The widespread occurrence of these compounds in water and soil samples has been demonstrated in a number of analytical studies. However, the data about their concentrations in biota samples is scarce. Moreover, the trophic transfer of pharmaceuticals remains largely unexplored, despite increasing evidence of the potential bioaccumulation of those compounds. Therefore, the main aim of this review is to present an overview of the current state of data about the bioaccumulation and analytical methodologies used for the determination of pharmaceutical residues in biota samples. This work focuses on the most commonly found pharmaceuticals in the environment: antibiotics, analgesic and anti-inflammatory drugs, steroid hormones, antihypertensives and antidepressants. We do hope that the collected data will allow a better understanding of pharmaceutical pollution and the exposure of non-target organisms. However, although impressive progress has undoubtedly been made, in order to fully understand the behavior of these chemicals in the environment, there are still numerous gaps to be filled in our overall knowledge in this field.

The leaching behavior of cyclophosphamide and ifosfamide from soil in the presence of co-contaminant--Mixture sorption approach.

Anticancer drugs (ACDs) exhibit high biological activity, they are cytotoxic, genotoxic, and are constantly released into the environment as a result of incomplete metabolism. Consequently they pose a serious threat to the environment and human health due to their carcinogenic, mutagenic and/or reproductive toxicity properties. Knowledge of their bioavailability, including their sorption to soils and their impact on the soil-groundwater pathway, is crucial for their risk assessment. Laboratory batch and column leaching tests are important tools for determining the release potential of contaminants from soil or waste material. Batch and column tests were carried out with soils differing in physicochemical properties, each spiked with cyclophosphamide (CK) or ifosfamide (IF). Moreover, due to the fact that environmental pollutants may occur as coexisting compounds in the soil the mobility evaluation for ACDs in the mixture with metoprolol (MET; ß-blocker) as a co-contaminant was performed. In order to assess appropriateness, the batch and column tests were compared. The release depended on the properties of both the soil and the presence of co-contaminants. The faster release was observed for coarse-grained soil with the smallest organic matter content (MS soil: 90% decrease in concentration until liquid-to-solid ratio (L/S) of 0.3 L kg(-1) for all tests' layout) than for loamy sand (LS soil: 90% decrease in concentration until ratio L/S of 0.75 L kg(-1)). ACDs are highly mobile in soil systems. Furthermore, the decrease of mobility of ifosfamide was observed with the presence of a co-contaminant (metoprolol) in both of the soils (in MS soil a decrease of 29%; in LS soil a decrease of 26%). The mobility of cyclophosphamide does not depend on the presence of a contaminant for MS soil, but also exhibits a decrease of 21% in LS soil.

Sorption of sulfisoxazole onto soil--an insight into different influencing factors.

Although sulfonamides (SAs) are among the most commonly used veterinary drugs and their presence in the environment is well documented, knowledge of their fate and behavior in the soil environment is still limited, especially for sulfisoxazole (SSX) which is characterized by the lowest (among other SAs) pK a value associated with acid-base equilibrium of sulfonamide group. Thus, this work was focused on determining the sorption potential of SSX onto natural soils differing in physicochemical properties. All the results were modeled using linear, Freundlich, Langmuir, Dubinin-Radushkevich, and Temkin sorption isotherms. The established sorption coefficients (K(d)) for SSX were quite low (from 0.27 to 0.95 L kg(-1)), which indicated that this substance is highly mobile and has the potential to run off into surface waters and/or infiltrate ground water. The sorption data of SSX is well fitted to the Freundlich isotherm model (R(2) > 0.968). Moreover, we assessed the sorption mechanism of these compounds in the edaphic environment with respect to organic matter (OM) content, pH, and ionic strength. To clarify the current state of knowledge, these factors were examined much more thoroughly than in previous investigations concerning other SAs. The wide range of ionic strength examined showed positive correlation of this factor and sorption of SAs. The results also yielded new insight into dependency of sorption of SAs on organic matter content in soil.

Beta-blockers in the environment: part II. Ecotoxicity study.

The increasing consumption of beta-blockers (BB) has caused their presence in the environment to become more noticeable. Even though BB are safe for human and veterinary usage, ecosystems may be exposed to these substances. In this study, three selected BB: propranolol, metoprolol and nadolol were subjected to ecotoxicity study. Ecotoxicity evaluation was based on a flexible ecotoxicological test battery including organisms, representing different trophic levels and complexity: marine bacteria (Vibrio fischeri), soil/sediment bacteria (Arthrobacter globiformis), green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor). All the ecotoxicological studies were supported by instrumental analysis to measure deviation between nominal and real test concentrations. Based on toxicological data from the green algae test (S. vacuolatus) propranolol and metoprolol can be considered to be harmful to aquatic organisms. However, sorption explicitly inhibits the hazardous effects of BB, therefore the risks posed by these compounds for the environment are of minor importance.

Thermodynamic studies for adsorption of ionizable pharmaceuticals onto soil.

Although pharmaceutical compounds (PCs) are being used more and more widely, and studies have been carried out to assess their presence in the environment, knowledge of their fate and behavior, especially under different environmental conditions, is still limited. The principle objective of the present work, therefore, is to evaluate the adsorption behavior of three ionizable, polar compounds occurring in different forms: cationic (propranolol - PRO), anionic (sulfisoxazole - SSX) and neutral (sulfaguanidine - SGD) onto soil under various temperature conditions. The adsorption thermodynamics of these researched compounds were extensively investigated using parameters such as enthalpy change (ΔH°), Gibbs free energy change (ΔG°) as well as entropy change (ΔS°). These calculations reveal that sorption of PRO is exothermic, spontaneous and enthalpy driven, sorption of SGD is endothermic, spontaneous and entropy driven whereas sorption of SSX is endothermic, spontaneous only above the temperature of 303.15K and entropy driven. Furthermore, we submit that the calculated values yield valuable information regarding the sorption mechanism of PRO, SGD and SSX onto soils.

Beta-blockers in the environment: part I. Mobility and hydrolysis study.

Beta-blockers (BB) are one of the most widely used pharmaceuticals whose presence in different environmental compartments has already been proven in concentrations of even up to a few µg L(-1). However, our knowledge of their fate in the environment is still scarce. To obtain a better understanding on the environmental behavior of three selected BB comprehensive laboratory experiments assessing their mobility and hydrolytic stability has been conducted. Propranolol, metoprolol and nadolol--the most commonly consumed and detected in environmental samples--were selected as representatives of this group of pharmaceuticals. The objectives of our research were: (i) evaluation of the sorption potential and an explanation of the sorption mechanisms of these compounds onto soil and clay mineral (kaolinite); and (ii) investigation of the hydrolytic stability of these BB according to OECD 111. This comprehensive study supports the Environmental Risk Assessment of these pharmaceuticals.

A new silylating reagent - dimethyl(3,3,3-trifluoropropyl)silyldiethylamine - for the derivatisation of non-steroidal anti-inflammatory drugs prior to gas chromatography-mass spectrometry analysis.

This paper discusses a new silylating reagent - dimethyl(3,3,3-trifluoropropyl)silyldiethylamine (DIMETRIS) - for the derivatisation of non-steroidal anti-inflammatory drugs (NSAIDs) prior to GC-MS analysis. DIMETRIS reacts with seven target compounds (diclofenac, ibuprofen, ketoprofen, naproxen, flurbiprofen and paracetamol, as well as salicylic acid, a degradation product of acetylsalicylic acid) at 30°C for 30min, producing mono-O-dimethyltrifluoropropylsilyl (mono-O-DMTFPS) derivatives. The mass spectra of these new derivatives are given and fully interpreted. The usefulness of mono-O-DMTFPS derivatives for the qualitative and quantitative analysis of NSAIDs using GC-MS is compared with that of trimethylsilyl and methyl analogues. Methyl derivatives are found to be less appropriate for this purpose because they yield the lowest detector responses during GC-MS measurements. Both silyl derivatives are more suitable for determining such NSAIDs, although the matrix effect with mono-O-DMTFPS derivatives is smaller. Finally, SPE-GC-MS(SIM) based on the derivatisation of NSAIDs by DIMETRIS is evaluated, validated and applied to the determination of these drugs in sea water (Baltic Sea) and wastewater samples collected in Poland. This work confirms that DIMETRIS is suitable for the trace analysis of NSAIDs in real samples and provides an interesting alternative to silylating and methylating reagents.

Dimethyl(3,3,3-trifluoropropyl)silyldiethylamine--a new silylating agent for the derivatization of ß-blockers and ß-agonists in environmental samples.

Research into alternative derivatizing agents remains a major task in the trace analysis of polar compounds using GC. DIMETRIS (dimethyl(3,3,3-trifluoropropyl)silyldiethylamine) is a new and interesting proposition in this field. This agent possesses strong nucleophilic properties and reacts selectively with hydroxyl groups. The derivatization reaction takes place in the absence of any catalysts. The derivatives possess good chromatographic properties and are easily detected by mass spectrometry. By introducing fluorine atoms into the structure of the derivatives, we were able to use an electron-capture detector for their GC determination. No degradation of new derivatives was observed after seven days of storage in a refrigerator or during the GC analyses. Unlike a number of acylation agents, DIMETRIS does not corrode the analytical equipment. In this work ß-blockers and ß-agonists were used for testing the derivatizing properties of DIMETRIS. Derivatization of these drugs was optimal at 30 °C for 30 min. The method quantification limits of the target compounds determined in tap water samples by SPE-GC-MS(SIM) ranged from 3 to 40 ng L(-1) and resembled those obtained with samples derivatized using a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1% chlorotrimethylsilane (TMCS) (hitherto regarded as optimal). This work confirmed that DIMETRIS is suitable for the trace analysis of pharmaceuticals in natural samples and provides an interesting alternative to silylating and acylating agents.