Grzegorz Nałęcz-Jawecki

The toxicity of cationic surfactants in four bioassays.

The purpose of this study was to investigate the toxicity of 15 quaternary ammonium compounds (QACs) in a battery of four bioassays comprising the bacterium Vibrio fischeri, two ciliated protozoa Spirostomum ambiguum and Tetrahymena thermophia, and the anostracean crustacean Artemia franciscana. The compounds were prepared by Professor Pernaks group at Poznań University of Technology (Poland). The toxicity of the test compounds was very high, with EC(LC)(50) values varying from 0.11 to 70 micromol/L. Microtox was the most sensitive bioassay, while the crustacean test was the least sensitive. Among the protozoa T. thermophila was 5-30 times less sensitive than S. ambiguum. The toxicity of the QACs depended on their structure, but no simple correlation was found for all the bioassays applied.

Estimation of the environmental risk posed by landfills using chemical, microbiological and ecotoxicological testing of leachates.

The leachates from 22 municipal solid waste (MSW) landfill sites in Southern Poland were characterized by evaluation of chemical, microbiological and ecotoxicological parameters. Chemical analyses were mainly focused on the identification of the priority hazardous substances according to Directive on Priority Substances, 2008/105/EC (a daughter directive of the WFD) in leachates. As showed, only five substances (Cd, Hg, hexachlorobutadiene, pentachlorobenzene and PAHs) were detected in the leachates. The compounds tested were absent or present at very low concentrations. Among them, only PAHs were found in all samples in the range from 0.057 to 77.2 μg L⁻¹. The leachates were contaminated with bacteria, including aerobic, psychrophilic and mesophilic bacteria, coliform and fecal coliforms, and spore-forming-bacteria, including Clostridium perfringens, and with filamentous fungi. From the analysis of specific microorganism groups (indicators of environmental pollution by pathogenic or opportunistic pathogenic organisms) it can be concluded that the landfill leachates showed sanitary and epidemiological hazard. In the ecotoxicological study, a battery of tests comprised of 5 bioassays, i.e. Microtox(®), Spirotox, Rotoxkit F™, Thamnotoxkit F™ and Daphtoxkit F™ magna was applied. The leachate samples were classified as toxic in 13.6%, highly toxic in 54.6% and very highly toxic in 31.8%. The Spirotox test was the most sensitive bioassay used. The percentage of class weight score was very high - above 60%; these samples could definitely be considered seriously hazardous and acutely toxic to the fauna and microflora. No correlations were found between the toxicity values and chemical parameters. The toxicity of leachate samples cannot be explained by low levels of the priority pollutants. It seems that other kinds of xenobiotics present in the samples at subacute levels gave the high aggregate toxic effect. The chemical, ecotoxicological and microbiological parameters of the landfill leachates should be analyzed together to assess the environmental risk posed by landfill emissions.

Ecotoxicological and microbiological characterization of soils from heavy-metal- and hydrocarbon-contaminated sites

The aims of this study were to characterize soils from industrial sites by combining physicochemical, microbiological, and ecotoxicological parameters and to assess the suitability of these assays for evaluation of contaminated sites and ecological risk assessment. The soil samples were taken from long-term contaminated sites containing high amounts of heavy metals (sites 1 and 2) or petroleum hydrocarbons (site 3) located in the upper Silesia Industrial Region in southern Poland. Due to soil heterogeneity, large differences between all investigated parameters were measured. Microbiological properties revealed the presence of high numbers of viable hetrotrophic microorganisms. Soil enzyme activities were considerably reduced or could not be detected in contaminated soils. Activities involved in N turnover (N mineralization and nitrification) were significantly (P < 0.05) higher in samples from the metal-contaminated sites than in samples from the hydrocarbon-contaminated site, whereas the opposite was observed for phosphatase activity. The Microtox test system appeared to be the most appropriate to detect toxicity and significant differences in toxicity between the three sites. The Ostracodtoxkit test was the most appropriate test system to detect toxicity in the hydrocarbon-contaminated soil samples. Correlation analysis between principal components (obtained from factor analysis) determined for physicochemical, microbiological, and ecotoxicological soil properties demonstrated the impact of total and water-extractable contents of heavy metals on toxicity.

Occurrence of antidepressant residues in the sewage-impacted Vistula and Utrata rivers and in tap water in Warsaw (Poland).

Antidepressants, even at low concentrations, can reveal some adverse effects on aquatic life due to disturbing homeostasis throughout the central and peripheral nervous system both in vertebrates and invertebrates. To date there have not been any reports regarding the presence of these pharmaceuticals in surface and tap waters in Eastern Europe. Therefore the aim of this study was to determine the presence of 21 antidepressant pharmaceuticals at specific points of the main Polish river - the Vistula, a smaller river of the Warsaw region - the Utrata, as well as in tap water samples of Warsaw. Samples were collected twice at one month intervals and analysed using solid-phase extraction (SPE) technique coupled with the liquid chromatography-electrospray ionisation-tandem mass spectrometer (LC-MS/MS) method operated under the multiple reaction monitoring mode (MRM). This is the first study where active compounds such as moclobemid or trazodone in the environment have been investigated. Environmental risk assessment of antidepressants in Poland was estimated on the basis of annuals sale data extracted from the NFZ (Narodowy Fundusz Zdrowia-National Health Service) base of reimbursed pharmaceuticals(1). Predicted environmental concentration (PEC) of target pharmaceuticals were compared with their measured concentration (MEC). Moreover, the application of the EMEA/CHMP guideline for environmental risk assessment of the antidepressants was discussed. The highest concentration of antidepressants was observed in the small river Utrata. In tap water only trace amounts of antidepressants including citalopram (up to 1.5ng/l), mianserin (up to 0.9ng/l), sertraline (<3.1ng/l), moclobemid (up to 0.3ng/l) and venlafaxine (up to 1.9ng/l) were detected. However this highlights their inadequate elimination in the drinking waste treatment facility. The presence of antidepressants in drinking water and the aquatic environment could have long-term effects even at low exposure level, especially since synergy amongst pharmaceutical pollutants may occur.

Evaluation of toxicity of medical devices using Spirotox and Microtox tests : I. Toxicity of selected toxicants in various diluents

Significant effort has been directed toward developing in vitro alternatives, which can be the first step of toxicity analysis. Tissue culture assays are currently the most popular in vitro tests for evaluating acute toxicity. The possibility of applying two bioassays using microorganisms in assessing the toxicity of extracts of medical devices was investigated. The Microtox test system--a luminescent bacteria toxicity test--assesses changes in light output from a luminescent bacteria, Vibrio fischeri. Spirotox used a large ciliate protozoan: Spirostomum ambiguum. The most widely used extraction solvent, 0.9% NaCl, must be concentrated up to 2% for Microtox and diluted nine times for the Spirotox test. The organic solvents ethanol, DMSO, and polyethylene glycol 400 were not toxic in either test in concentrations of 1-2%. The toxicity of reference compounds Hg, Cd, Zn, Pb, and SDS was examined in various diluents. The sequence of toxicity of the tested compounds in Spirotox and Microtox was: Hg > Cd > Zn > Pb > SDS, and Hg > Pb = Zn > SDS > Cd, respectively. Addition of organic solvents changed the toxicity of compounds tested in 60% of Spirotox tests and only in 25% of Microtox tests. Changes were low, not exceeding 100% in almost all cases. No correlation was observed between diluent and toxicant in either bioassay.

Nanocrystalline hydroxyapatite doped with selenium oxyanions: A new material for potential biomedical applications

Selenium-substituted hydroxyapatites containing selenate SeO4(2-) or selenite SeO3(2-) ions were synthesized using a wet precipitation method. The selenium content was determined by atomic absorbance spectrometry. The raw, unsintered powders were also characterized using powder X-ray diffraction, middle-range FT-IR spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopic microanalysis. The synthesized apatites were found to be pure and nanocrystalline with a crystal size similar to that in bone mineral. The incorporation of selenium oxyanions into the crystal lattice was confirmed. The toxicity of hydroxyapatites containing selenite or selenate ions was evaluated with a protozoan assay and bacterial luminescence test.

Synthesis and study of controlled release of ofloxacin from polyester conjugates

New polymeric conjugates were prepared coupling ofloxacin to two-, three-, four and six-arm, star-shaped poly(ɛ-caprolactone) and polylactide. The homopolymers were synthesized via ring-opening polymerization of ɛ-caprolactone, l-lactide and rac-lactide in the presence of glycerol, penthaerythritol, dipentaerythritol and poly(ethylene glycol) as initiators and stannous octoate as a catalyst. The conjugates were characterized by GPC, MALDI-TOF MS, NMR, IR and viscosity methods. Content of Sn has been investigated in polymers by electrothermal atomic absorption spectrometry. Toxicity of monomers, initiators and polymers were evaluated with bacterial luminescence test and two protozoan assays. The in vitro release of ofloxacin from obtained conjugates in pH 7 was investigated.

Phytotoxicity of Sulfamethazine Soil Pollutant to Six Legume Plant Species

The effect of traces of sulfamethazine (SMZ) in soil (0.01, 0.1, 0.25, 1, 5, 15, and 20 mM) on cellular distribution of cytochrome c oxidase activity, shoot and root growth, and leachate electroconductivity was analyzed in germinating seeds of yellow lupin, pea, lentil, soybean, adzuki bean, and alfalfa. Results showed that a high activity of cytochrome c oxidase in mitochondria correlated with high seed vigor and viability. The appearance of necroses and root decay was associated with a decrease in the activity of mitochondrial cytochrome c oxidase but was accompanied by an increase in cytosolic cytochrome c oxidase activity. A short exposure period of seeds (3 and 6 d) to sulfamethazine did not influence germination. Elongation of roots and stems was more sensitive than germination rate as an indicator of soil contamination by sulfamethazine. Among all tested leguminous plants, yellow lupin was the most reliable bioindicator of SMZ contaminated soil.

Evaluation of in vitro biotransformation of propranolol with HPLC, MS/MS, and two bioassays.

The majority of human drugs enter aquatic systems after ingestion and subsequent excretion in the form of parent compounds and metabolites. Environmental exposure to drug metabolites has not been reported so far. The goal of the present study was to apply the in vitro method of biotransformation of compounds with S9 fraction to the ecotoxicological analysis. β‐adrenoceptor antagonist propranolol was metabolized with S9 rat liver fraction. The parent compound was quantified with HPLC, and the metabolites were identified with QToF MS. Propranolol was metabolized rapidly, during the first hour its level decreased by 80 and 50% of the initial 20 and 100 mg L−1, respectively. Ten peaks were observed on the HPLC‐RF chromatogram. Four peaks were identified with QToF MS/MS propranolol (m/z = 260), N‐desisopropylpropranolol (m/z = 218), hydroxypropranolol (m/z = 276), and hydroxy N‐desisopropranolol glycol (m/z = 235). Then the ecotoxicity of the reaction mixture was studied with two bioassays Spirotox with the protozoan Spirostomum ambiguum and Thamnotoxkit F™ with the anostracean crustacean Thamnocephalus platyurus. Propranolol is twofolds more toxic to Spirotox than to Thamnotoxkit F with 24 h‐EC50 = 1.77 mg L−1 and 24 h‐LC50 = 3.86 mg L−1, respectively. No statistically significant differences were found between the toxicity of the reaction mixtures after S9 biotransformation and the propranolol solution. These results indicate that the biological activity of the metabolites is similar to that of the parent drug. The presented method of in vitro biotransformation of drugs with S9 fraction followed by HPLC and ecotoxicity tests, may be used as screening method for evaluation of the toxicity of drug metabolites.

Polylactide Conjugates of Camptothecin with Different Drug Release Abilities

Camptothecin-polylactide conjugates (CMPT-PLA) were synthesized by covalent incorporation of CMPT into PLA of different microstructure, i.e., atactic PLA and atactic-block-isotactically enriched PLA (Pm = 0.79) via urethane bonds. The kinetic release of CPMT from CMPT-PLA conjugates, tested in vitro under different conditions, is possible in both cases and notably, strongly dependent on PLA microstructure. It shows that release properties of drug-PLA conjugates can be tailored by controlled design of the PLA microstructure, and allow in the case of CMPT-PLA conjugates for the development of highly controlled biodegradable CMPT systems—important delivery systems for anti-cancer agents.