Effects of diclofenac, sulfamethoxazole, and wastewater from constructed wetlands on Eisenia fetida: impacts on mortality, fertility, and oxidative stress.

Soil contamination with micropollutants is an important global problem and the impact of these pollutants on living organisms cannot be underestimated. The effects of diclofenac (DCF) and sulfamethoxazole (SMX), their mixture (MIX), and wastewater containing these drugs on the mortality and reproduction of Eisenia fetida were investigated. The impact on the activities of antioxidant enzymes in earthworm cells was also assessed. Furthermore, the influence of the following parameters of the vertical flow constructed wetlands on wastewater toxicity was investigated: the dosing system, the presence of pharmaceuticals and the plants Miscanthus giganteus. The compounds and their mixture significantly affected the reproduction and mortality of earthworms. The calculated values of LC50,28 days values were 3.4 ± 0.3 mg kg-1 for DCF, 1.6 ± 0.3 mg kg-1 for SMX, and 0.9 ± 0.1 mg kg-1 for MIX. The EC50 (reproduction assay) for DCF was 1.2 ± 0.2 mg kg-1, whereas for SMX, it was 0.4 ± 0.1 mg kg-1, and for MIX, it was 0.3 ± 0.1 mg kg-1, respectively. The mixture toxicity index (MTI) was calculated to determine drug interactions. For both E. fetida mortality (MTI = 3.29) and reproduction (MTI = 3.41), the index was greater than 1, suggesting a synergistic effect of the mixture. We also observed a negative effect of wastewater (raw and treated) on mortality (32% for raw and 8% for treated wastewater) and fertility (66% and 39%, respectively) of E. fetida. It is extremely important to analyze the harmfulness of microcontaminants to organisms inhabiting natural environments, especially in the case of wastewater for irrigation of agricultural fields.

Alternative Methods for Skin-Sensitization Assessment.

Skin sensitization is a term used to refer to the regulatory hazard known as allergic contact dermatitis (ACD) in humans or contact hypersensitivity in rodents, an important health endpoint considered in chemical hazard and risk assessments. Information on skin sensitization potential is required in various regulatory frameworks, such as the Directive of the European Parliament and the Council on Registration, Evaluation and Authorization of Chemicals (REACH). The identification of skin-sensitizing chemicals previously required the use of animal testing, which is now being replaced by alternative methods. Alternative methods in the field of skin sensitization are based on the measurement or prediction of key events (KE), i.e., (i) the molecular triggering event, i.e., the covalent binding of electrophilic substances to nucleophilic centers in skin proteins; (ii) the activation of keratinocytes; (iii) the activation of dendritic cells; (iv) the proliferation of T cells. This review article focuses on the current state of knowledge regarding the methods corresponding to each of the key events in skin sensitization and considers the latest trends in the development and modification of these methods.

Towards Sustainable Wastewater Treatment: Bioindication as a Technique for Supporting Treatment Efficiency Assessment.

Constructed wetlands (CWs) are a promising alternative for conventional methods of wastewater treatment. However, the biggest challenge in wastewater treatment is the improvement of the technology used so that it is possible to remove micropollutants without additional costs. The impact of wastewater treatment in CWs on toxicity towards Aliivibrio fischeri, Daphnia magna and Lemna minor was investigated. The effects of feeding regime (wastewater fed in five batches per week at a batch volume of 1 L, or twice per week at a batch volume of 2.5 L) and the presence of pharmaceuticals (diclofenac and sulfamethoxazole), as well as the presence of Miscantus giganteus plants in CW columns (twelve of the 24 columns that were planted) were analyzed. A reduction in toxicity was observed in all experimental setups. The effluents from constructed wetlands were classified as moderately toxic (average TU for A. fischeri, D. magna and L. minor was 0.9, 2.5 and 5.5, respectively). The feeding regime of 5 days of feeding/2 days of resting resulted in a positive impact on the ecotoxicological and chemical parameters of wastewater (removal of TOC, N-NH4 and pharmaceuticals). Extended exposure of Miscantus giganteus to the wastewater containing pharmaceuticals resulted in elevated activity of antioxidant enzymes (catalase and superoxide dismutase) in leaf material.

Inactivation of Spores and Vegetative Forms of Clostridioides difficile by Chemical Biocides: Mechanisms of Biocidal Activity, Methods of Evaluation, and Environmental Aspects.

Clostridioides difficile infections (CDIs) are the most common cause of acquired diseases in hospitalized patients. Effective surface disinfection, focused on the inactivation of the spores of this pathogen, is a decisive factor in reducing the number of nosocomial cases of CDI infections. An efficient disinfection procedure is the result of both the properties of the biocidal agent used and the technology of its implementation as well as a reliable, experimental methodology for assessing the activity of the biocidal active substance based on laboratory models that adequately represent real clinical conditions. This study reviews the state of knowledge regarding the properties and biochemical basis of the action mechanisms of sporicidal substances, with emphasis on chlorine dioxide (ClO2). Among the analyzed biocides, in addition to ClO2, active chlorine, hydrogen peroxide, peracetic acid, and glutaraldehyde were characterized. Due to the relatively high sporicidal effectiveness and effective control of bacterial biofilm, as well as safety in a health and environmental context, the use of ClO2 is an attractive alternative in the control of nosocomial infections of CD etiology. In terms of the methods of assessing the biocidal effectiveness, suspension and carrier standards are discussed.

Developing a screening test for toxicity studies of prenatal development with the use of Hydra attenuata and embryos of zebrafish.

11 active substances used in pesticides were selected. Substances were divided into three groups depending the effect on embryos or fetuses of laboratory animals: 1 - damaging effect on embryos or fetuses (embryotoxic, fetotoxic or teratogenic), 2 - damaging effect on embryos or fetuses, but only at dose toxic for mother (maternal toxicity), 3 - no damaging effect. Changes for hydra in acute toxicity tests and recovery tests were assessed on an change scale from 0 to 10. The index of the effect on development (TI) for hydras was calculated for every compound. Changes in zebrafish embryos were assessed using a descriptive method. Pearson correlation coefficient showed the correlation between the concentration and the toxic effect in the zebrafish embryos for the substances of the first group. The study showed that substances having a strong damaging effect on fetuses cause changes that are apparent and easy to evaluate both in hydras and zebrafish embryos. A scoring system was introduced to evaluate the changes of hydras and zebrafish embryos. The point system of evaluation of changes allows quick classification of a substance as potentially embryotoxic, fetotoxic or teratogenic. It allows developing a cheap and fast method alternative to prenatal developmental toxicity studies, a screening method that enables substances of great teratogenic potential to be excluded from studies on laboratory animals.

Removal and transformation of sulfamethoxazole in acclimated biofilters with various operation modes - Implications for full-scale application.

The knowledge gaps regarding the degradation of sulfamethoxazole (SMX) in biofilters include the effect of aeration, constant feeding with readily biodegradable organic carbon and the presence of reactive media such as manganese oxides (MnOx). Thus, the goal of this study was to assess the removal of SMX in lab-scale biofilters with various operation variables: aeration, presence of MnOx as an amendment of filtering medium and the presence of readily biodegradable organic carbon (acetate). The sand used in the experiment as a filtering medium was previously exposed to the presence of SMX and acetate, which provided acclimation of the biomass. The removal of SMX was complete (>99%) with the exception of the unaerated columns fed with the influent containing acetate, due to apparent slower rate of SMX degradation. The obtained results suggest that bacteria were able to degrade SMX as a primary substrate and the degradation of this compound was subsequent to the depletion of acetate. The LC-MS/MS analysis of the effluents indicated several biotransformation reactions for SMX: (di)hydroxylation, acetylation, nitrosation, deamonification, S-N bond cleavage and isoxazole-ring cleavage. The relative abundance of transformation products was decreased in the presence of MnOx or acetate. Based on the Microtox assay, only the effluents from the unaerated columns filled with MnOx were classified as non-toxic. The results offer important implications for the design of biofilters for the elimination of SMX, namely that biofilters offer the greatest performance when fed with secondary wastewater and operated as non-aerated systems with a filtering medium containing MnOx.

Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

Improved technologies are needed for sustainable management of sewage sludge (SS). The torrefaction (also known as biomass "roasting") is considered a pretreatment of SS before use in agriculture. However, it is not known whether the torrefaction has the potential to decrease heavy metals' (HMs) leachability and the SS toxicity. Thus, the aim of the study was to evaluate the influences of the SS torrefaction parameters (temperature and process time) on HM contents in biochar, HM leachability, and biochar toxicity, and compare them with raw SS. The experiments were designed in 18 combinations (six temperatures, 200, 220, 240, 260, 280, and 300 °C; and three process times-20, 40, 60 min). Standard tests were used to determine HMs content, leachability, and toxicity. Results indicated that the torrefaction did not increase (p < 0.05) the HM content in comparison to the raw SS. The leachability of Zn, Ni, Cu, Cr, and Mn from SS biochars was similar to raw SS. However, the degree of leachability varied significantly (p < 0.05) from as low as 0.1% for Cu to high as 16.7% for Cd. The leachability of Cd (<16.7%) and Pb (<11.9%) from biochars was higher than from raw SS (<6.1% and <2.4%, respectively). The leachability of Cd from SS biochar, in five torrefaction combinations, was higher than the threshold value for hazardous waste. It is recommended that site-specific decisions are made for torrefaction of SS with respect to its HM content, as the resulting biochar could be considered as hazardous waste, depending on the feedstock. Moreover, the biochar produced under the whole range of temperatures during 20 min retention time significantly (p < 0.05) increased the Daphnia magna Straus mobility inhibition by up to 100% in comparison to the biochar obtained during 40 and 60 min torrefaction. Taking into account the increased leachability of specific HMs and D. magna Straus mobility inhibition, biochar should be considered a potentially hazardous material. Future research should focus on biochar dosage as a fertilizer in relation to its toxicity. Additional research is warranted to focus on the optimization of SS torrefaction process parameters affecting the toxicity.

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.

Antimicrobial pharmaceuticals in the aquatic environment - occurrence and environmental implications.

The environmental occurrence of antimicrobial pharmaceuticals and antibiotic resistant bacteria and antibiotic resistant genes has become a global phenomenon and a multifaceted threat. Integrated actions of many parties are needed to prevent further aggravation of the problem. Well-directed actions require clear understanding of the problem, which can be ensured by frequent revaluation of the existing knowledge and disseminating it among relevant audiences. The goal of this review paper is to discuss the occurrence and abundance of antimicrobial pharmaceuticals in the aquatic environment in context of adverse effects caused directly by these substances and the threat associated with the antibiotics resistance phenomenon. Several classes of antimicrobial pharmaceuticals (aminoglycosides, ß-lactams, glycopeptides, macrolides, fluoroquinolones, sulfonamides and trimethoprim, tetracyclines) have been selected to illustrate their sources, environmental abundance, degradation routes (transformation products) and environmental implications including their ecotoxic effect and the spread of antibiotic resistance within the compartments of the aquatic environment and wastewater treatment plants. Wastewater treatment plants are indeed the main source responsible for the prevalence of these factors in the aquatic environment, since predominantly the plants have not been designed to retain antimicrobial pharmaceuticals. In order to limit the prevalence of these impurities into the environment, better source control is recommended as well as the establishment of stricter environmental quality standards. Counteracting all the above-mentioned threats requires to undertake integrated activities based on cooperation of professionals and scientists from various fields of science or industry, such as environmental sciences, medicine, veterinary, pharmacology, chemical engineering and others.

Removal and transformation of benzotriazole in manganese-oxide biofilters with Mn(II) feeding.

The aim of this study was to evaluate the treatment of organic-carbon-deficient wastewater containing benzotriazole (BTA) in lab-scale aerated biofilters filled with natural manganese oxide ore, sand coated with synthetic manganese oxides and sand (as a control material) in terms of BTA removal efficiency, its transformation products and ecotoxicological impact of the treated wastewater. Additionally, the effect of Mn(II) feeding was tested. The removal of BTA in all the biofilters was ≥97%. The contribution of the biotic removal of this compound was 15%, 50%, and 75% in the systems filled with sand, synthetic and natural manganese oxides, respectively. Only the columns filled with natural manganese oxides provided significant removal of DOC and decrease of UV254 and SUVA254, with even more pronounced effect with Mn(II) feeding. The presence of Mn(II) was also found to enhance the removal of NNH4 in the systems filled with either form of manganese oxides, otherwise the removal of NNH4 was negligible or negative. The transformation reactions of BTA were methylation, hydroxylation, and triazole ring cleavage. Based on the number of compounds and their relative abundance, the methylated transformation products were predominant in the effluent. The reduction of the ecotoxicity (Microtox bioassay) of the effluents was positively correlated with the decrease of UV254, SUVA and DOC and only moderately with the removal of BTA. This study has shown that the natural manganese oxide ore provides the broadest set of services as a filtering material for aerated biofilters treating carbon-deficient wastewater containing BTA.

The comet assay for the evaluation of genotoxic potential of landfill leachate.

Genotoxic assessment of landfill leachate before and after biological treatment was conducted with two human cell lines (Me45 and NHDF) and Daphnia magna somatic cells. The alkali version of comet assay was used to examine genotoxicity of leachate by DNA strand breaks analysis and its repair dynamics. The leachate samples were collected from Zabrze landfill, situated in the Upper Silesian Industrial District, Poland. Statistically significant differences (Kruskal-Wallice ANOVA rank model) were observed between DNA strand breaks in cells incubated with leachate before and after treatment (P < 0.001). Nonparametric Friedman ANOVA confirmed time-reliable and concentration-reliable cells response to leachate concentration. Examinations of chemical properties showed a marked decrease in leachate parameters after treatment which correlate to reduced genotoxicity towards tested cells. Obtained results demonstrate that biological cotreatment of leachate together with municipal wastewater is an efficient method for its genotoxic potential reduction; however, treated leachate still possessed genotoxic character.

Acute toxicity and genotoxicity of five selected anionic and nonionic surfactants.

The results of four toxicity bioassays of selected anionic and nonionic surface active agents were presented. Three widely used anionic surfactants that belong to alkyl sulphates (AS), alkylbenzene sulphonates (LAS) and alkylpolyoxyethylene sulphates (AES) as well as nonionic surfactants: polyoxyethylene alkyl ethers (AE) and polyoxylethylene alkylphenyl ethers (APE) were tested. Three different toxicity assays to aquatic organisms: Physa acuta Draparnaud, Artemia salina and Raphidocelis subcapitata were applied. Additionally, the genotoxicity test with Bacillus subtilis M45 Rec- and H17 Rec+ strains was performed. The obtained results showed that none of the surfactants studied was genotoxic at the concentration 1000 mg l(-1). On the basis of toxicity tests to aquatic organisms all tested anionic surfactants were harmful (LC50 between 10 and 100 mg l(-1)), whereas nonionic ones were toxic (LC50 between 1 and 10 mg l(-1)) or even highly toxic (LC50 below 1 mg l(-1)). Moreover, the bigger was the molecular weight of the tested compound, the higher toxicity was observed.

An assessment of the toxicity of pyridinium chlorides and their biodegradation intermediates.

Toxicity investigations were conducted for four pyridinium chlorides belonging to cationic surface-active substances (CSAS), which differed from each other in the numbers of methyl groups (CH(3)) in pyridinium ring. The crustacean Daphnia magna, the fish Lebistes reticulatus and the alga Scenedesmus quadricauda were chosen as biotests. Toxicity of examined preparations appeared to be very high but did not depend on their chemical structure. S. quadricauda was the most sensitive organism. Toxicity of intermediate products obtained in biological oxidation process was also examined. Biodegradation was conducted according to the "river water test". It was found that only partial degradation took place while pyridinium chlorides constituted main energy and carbon source. Presence of biodegradation intermediate products was shown on the basis of 1H NMR analysis. Intermediates were not toxic to any biotests.

Genotoxicological effects of some phenoxyherbicides and their metabolites on Bacillus subtilis M45 Rec- and H17 Rec+ strains.

Because they are used in a number of commercial preparations phenoxyacetic acids and their salts can occur in wastewater. During their degradation genotoxic substances may be created. The results of investigations of biodegradability and genotoxicity of some phenoxyherbicides are presented. Commercial formulations of 2,4-D (Aminopielik 720) and MCPA (Chwastox Extra) were the substrates studied. Biodegradation tests were conducted according to OECD guidelines for testing of chemicals--confirmatory test (OECD Method 303 A). Genotoxicity tests were conducted with Bacillus subtilis strains according to the method of [Chemical Mutagens, vol. 6, Plenum Press. New York, 1980, p. 149]. Genotoxicity of biodegradation products was also studied. Both commercial formulations were biodegradable. Aminopielik 720 was potentially genotoxic but only at great concentrations while Chwastox Extra was not genotoxic. Biodegradation products of neither compound were genotoxic.