Joanna Maszkowska

Hydrolysis of sulphonamides in aqueous solutions.

Hydrolysis is one of the most common reactions controlling abiotic degradation and is one of the main paths by which substances are degraded in the environment. Nevertheless, the available information on this process for many compounds, including sulphonamides (a group of antibiotic drugs widely used in veterinary medicine), is very limited. This is the first study investigating the hydrolytic stabilities of 12 sulphonamides, which were determined according to OECD guideline 111 (1st category reliability data on the basis of regulatory demands on data quality for the environmental risk assessment of pharmaceuticals). Hydrolysis behaviour was examined at pH values normally found in the environment. This was prefaced by a discussion of the acid-base properties of sulphonamides. All the sulphonamides tested were hydrolytically stable at pH 9.0, nine (apart from sulphadiazine, sulphachloropyridazine and sulphamethoxypyridazine) were stable in this respect at pH 7.0 and two (sulphadiazine and sulphaguanidine) at pH 4.0 (hydrolysis rate≤10%; t(0.5 (25°C))>1 year). The degradation products were identified, indicating two independent mechanisms of this process. Our results show that under typical environmental conditions (pH and temperature) sulphonamides are hydrolytically stable with a long half-life; they thus contribute to the on-going assessment of their environmental fate.

Sulfadimethoxine and sulfaguanidine: their sorption potential on natural soils.

Sulfonamides (SAs) are one of the oldest groups of veterinary chemotherapeutic agents. As these compounds are not completely metabolized in animals, a high proportion of the native form is excreted in feces and urine. They are therefore released either directly to the environment in aquacultures and by grazing animals, or indirectly during the application of manure or slurry. Once released into the environment, SAs become distributed among various environmental compartments and may be transported to surface or ground waters. The physicochemical properties of SAs, dosage and nature of the matrix are the factors mainly responsible for their distribution in the natural environment. Although these rather polar compounds have been in use for over half a century, knowledge of their fate and behavior in soil ecosystems is still limited. Therefore, in this work we have determined the sorption potential of sulfadimethoxine and sulfaguanidine on various natural soils. The influence on sorption of external factors, such as ionic strength and pH, were also determined. The sorption coefficients (K(d)) obtained for the sulfonamides investigated were quite low (from 0.20 to 381.17 mL g(-1) for sulfadimethoxine and from 0.39 to 35.09 mL g(-1) for sulfaguanidine), which indicated that these substances are highly mobile and have the potential to run off into surface waters and/or infiltrate ground water. Moreover, the sorption of these pharmaceuticals was found to be influenced by OC, soil solution pH and ionic strength, with higher K(d) values for soils of higher OC and lower K(d) values with increasing pH and ionic strength.

Aquatic toxicity of four veterinary drugs commonly applied in fish farming and animal husbandry.

Doramectin (DOR), metronidazole (MET), florfenicol (FLO), and oxytetracycline (OXT) are among the most widely used veterinary drugs in animal husbandry or in aquaculture. Contamination of the environment by these pharmaceuticals has given cause for concern in recent years. Even though their toxicity has been thoroughly analyzed, knowledge of their ecotoxicity is still limited. We investigated their aquatic toxicity using tests with marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustaceans (Daphnia magna). All the ecotoxicological tests were supported by chemical analyses to confirm the exposure concentrations of the pharmaceuticals used in the toxicity experiments, since deviations from the nominal concentration can result in underestimation of biological effects. It was found that OXT and FLO have a stronger adverse effect on duckweed (EC50=3.26 and 2.96mgL(-1) respectively) and green algae (EC50=40.4 and 18.0mgL(-1)) than on bacteria (EC50=108 and 29.4mgL(-1)) and crustaceans (EC50=114 and 337mgL(-1)), whereas MET did not exhibit any adverse effect in the tested concentration range. For DOR a very low EC50 of 6.37×10(-5)mgL(-1) towards D. magna was determined, which is five orders of magnitude lower than values known for the toxic reference compound K2Cr2O7. Our data show the strong influence of certain veterinary drugs on aquatic organisms and contribute to a sound assessment of the environmental hazards posed by commonly used pharmaceuticals.

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.

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.

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.

Development of sensitive and reliable LC-MS/MS methods for the determination of three fluoroquinolones in water and fish tissue samples and preliminary environmental risk assessment of their presence in two rivers in northern Poland

Antibiotic consumption (e.g. fluoroquinolones (FQs)) and, as a consequence, their presence in the environment, have received a lot of attention in the last several years due to increasing numbers of diseases and infections that are becoming resistant to traditional treatments for both humans and animals. In addition, even though antibiotics are safe for human and veterinary usage, ecosystems may be exposed to these substances. In this study, analytical methods for determining enrofloxacin (ENR), norfloxacin (NOR) and ciprofloxacin (CIP) in water samples and fish tissue based on the LC-MS/MS technique were developed and validated. As there is no data available concerning the risks posed by antibiotics in Poland, the proposed methods were applied for monitoring drug presence in environmental samples collected from two rivers in northern Poland. Evaluations of the ecotoxicity of ENR, NOR and CIP towards four different species of aquatic organisms: marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustacean (Daphnia magna), were also carried out. All the investigated compounds were detected at least once in the survey. NOR was found to be the most ubiquitous drug with concentrations of up to 442.8 ng L(-1). Moreover, it was established that L. minor is the most sensitive species to the investigated drugs (EC50NOR = 0.13 mg L(-1), EC50ENR = 0.22 mg L(-1) and EC50CIP = 0.34 mg L(-1)). The calculated risk quotient (RQ) values confirmed that the concentrations of the investigated FQs in the environmental samples were at a level of moderate environmental risk (1

Determination of metronidazole residues in water, sediment and fish tissue samples

Metronidazole (MNZ) is an antibacterial and antiprotozoal drug used in veterinary and human medicine. Its continual entry into the environment and its biological properties may have significant, long-term effects on the stability of ecosystems because MNZ and its metabolites possess mutagenic, carcinogenic and toxic properties. For this reason, the application of MNZ in food-producing species is prohibited in the EU, the USA and other countries. To ensure human food safety and to protect the environment, robust and reliable screening and confirmatory tests capable of the low-level detection of MNZ residues are required. The development of methods for MNZ determination in biological and environmental samples is thus an important analytical task in environmental and food science. This work focuses on the evaluation of a method for determining MNZ in water, sediment and fish tissue samples using liquid chromatography--ion trap mass spectrometry (LC-MS/MS). MNZ was extracted from waters on Strata XC cartridges using solid phase extraction (SPE), and from sediments and fish tissues by solid-liquid extraction (sediment: 15 mL 0.1 M HCl (pH=0.6), 15 min; fish tissue: 15 mL 1% CH3COOH in ACN, 1 min; drying: 5 g MgSO4(anhyd.; 30 s) with SPE purification of the extracts (from sediment: Strata XC cartridge; from fish tissue: Supelco NH2 cartridge). The optimal procedure that we developed was validated in order to confirm its reliability and sensitivity. Matrix effects (ME) were established. Absolute recoveries ranged from 89.3% to 97.2%, and the method detection limits were 3.4 ng L(-1) (water samples), 0.4 ng g(-1) (sediment samples) and 0.3 ng g(-1) (tissue samples). These methods were used to determine MNZ in surface waters, sediments and fish tissues from the Polish River Gościcina; MNZ was found in all these matrices. The highest concentrations in water, sediment and tissue were 136.2 ng L(-1), 12.0 ng g(-1) and 1.5 ng g(-1) respectively. The results confirmed that these methods are suitable for the simultaneous analysis of waters, sediments and fish tissues for the presence of MNZ.

Column and batch tests of sulfonamide leaching from different types of soil

Sulfonamides (SAs) and their metabolites present severe hazards to human health and the environment, mainly because of antibiotic resistance. Knowledge of their bioavailability, including their sorption to soils and their impact on the soil-groundwater pathway, is crucial to their risk assessment. Laboratory batch and column leaching tests are important tools for determining the release potential of contaminants from soil or waste materials. Batch and column tests were carried out with soils differing in particle size distribution, organic matter content and pH, each spiked with sulfonamides (sulfadimethoxine (SDM), sulfaguanidine (SGD), sulfisoxazole (SX)). In order to test the applicability of leaching tests to polar contaminants batch and column tests were also compared. In the column tests, release was found to depend on the properties of both soil and sulfonamides. The fastest release was observed for coarse-grained soil with the smallest organic matter content (MS soil; 100% decrease in concentration until liquid-to-solid ratio (L/S) of 0.9 L kg(-1) for all SAs). The slowest release was established for sulfadimethoxine (24.5% decrease in concentration until L/S 1.22 L kg(-1)). The results of the batch and column tests were comparable to a large extent, with slightly higher concentrations being obtained in the column test experiments of fine-grained soils with a high organic matter content.

Toxicity of anthelmintic drugs (fenbendazole and flubendazole) to aquatic organisms

Flubendazole (FLU) and fenbendazole (FEN) belong to benzimidazoles—pharmaceuticals widely used in veterinary and human medicine for the treatment of intestinal parasites as well as for the treatment of systemic worm infections. In recent years, usage of these drugs increased, which resulted in a larger contamination of the environment and possible negative effects on biota. Hence, in our research, we investigated an aquatic ecotoxicity of these pharmaceuticals towards: marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustacean (Daphnia magna). Ecotoxicity tests were combined with chemical analysis in order to investigate the actual exposure concentration of the compounds used in the experiment as well as to stability and adsorption studies. As a result, study evaluating sensitivity of different aquatic organisms to these compounds and new ecotoxicological data is presented. The strongest negative impact of FLU and FEN was observed to D. magna.