The impact of nanoparticles on fish health is still a matter of debate, since nanotechnology is quite recent. In this study, freshwater benthonic juvenile fish Prochilodus lineatus were exposed through water to three concentrations of TiO₂ (0.1, 1, and 10 μg l⁻¹) and ZnO (7, 70, and 700 μg l⁻¹) nanoparticles, as well as to a mixture of both (TiO₂ 1 μg l⁻¹ + ZnO 70 μg l⁻¹) for 5 and 30 days. Nanoparticle characterization revealed an increase of aggregate size in the function of concentration, but suspensions were generally stable. Fish mortality was high at subchronic exposure to 70 and 700 μg l⁻¹ of ZnO. Nanoparticle exposure led to decreased acetylcholinesterase activity either in the muscle or in the brain, depending on particle composition (muscle—TiO₂ 10 μg l⁻¹; brain—ZnO 7 and 700 μg l⁻¹), and protein oxidative damage increased in the brain (ZnO 70 μg l⁻¹) and gills (ZnO 70 μg l⁻¹ and mixture) but not in the liver. Exposed fish had more frequent alterations in the liver (necrosis, vascular congestion, leukocyte infiltration, and basophilic foci) and gills (hyperplasia and epithelial damages, e.g., epithelial disorganization and epithelial loss) than the control fish. Thus, predicted concentrations of TiO₂ and ZnO nanoparticles caused detectable effects on P. lineatus that may have important consequences to fish health. But, these effects are much more subtle than those usually reported in the scientific literature for high concentrations or doses of metal nanoparticles.

The aim of study was to integrate chemical analyses and toxicity bioassays in order to assess the environmental risk connected with the presence of trace elements in the sediments. This study examined the ecological significance of trace elements in bottom sediments by applying a set of complementary sediment quality assessment methods sediment quality guidelines (SQGs) (mean probable effect concentration quotient (PECQ)), potential ecological risk index (PERI), contamination degree (C d) and two bioassays: the bacterial luminescence inhibition test with Vibrio fischeri on sediment elutriates and the direct contact test with the ostracod crustacean Heterocypris incongruens. The samples were collected from 50 stations of Rybnik reservoir. The reservoir is a region with enormous concentration of industry, mainly hard coal mining, electric power industry, and transportation. Despite the high diversity in metal concentration in the sediments, the spatial distribution of trace elements in the sediments was very similar. Moreover, the strong positive correlations between individual pairs of trace elements indicate that they may derive from a similar source and move together. According to mean PECQs, 68 % of the samples were potentially non-toxic and 32 % of the samples were potentially toxic. PERI values suggested that 70 % of the sediment sampling sites exhibited low ecological risk from metal pollution while 24 % of the samples had severe and serious risk. Based on our combined evaluation, we believe that Cd and Cu in the sediment samples frequently caused adverse biological effects. Higher toxic responses were observed in the Microtox test than in the Ostracodtoxkit test. All the sediment samples were found toxic to V. fischeri, and 96 % of the samples had effect percentages >50 %. For H. incongruens, 12 % of the sediments were not toxic and 44 % had effect percentages >50 %. In order to perform a complex assessment of the environmental impact of metal pollution, both chemical and ecotoxicological analysis should be carried out.

In the present study, the endocrine activity of the antiepileptic pharmaceutical carbamazepine (CBZ) in the crustacean Daphnia magna was assessed. To assess the hormonal activity of the drug, we exposed maternal daphnids and embryos to environmental relevant concentrations of CBZ (ranging from 10 to 200 μg/L) and to mixtures of CBZ with fenoxycarb (FEN; 1 μg/L). Chronic exposure to CBZ significantly decreased the reproductive output and the number of molts of D. magna at 200 μg/L. This compound induced the production of male offspring (12 ± 1.7 %), in a non-concentration-dependent manner, acting as a weak juvenile hormone analog. Results showed that this substance, at tested concentrations, did not antagonize the juvenoid action of FEN. Further, CBZ has shown to be toxic to daphnid embryos through maternal exposure interfering with their normal gastrulation and organogenesis stages but not producing direct embryo toxicity. These findings suggest that CBZ could act as an endocrine disruptor in D. magna as it decreases the reproductive output, interferes with sex determination, and causes development abnormality in offspring. Therefore, CBZ could directly affect the population sustainability.

In the present study, response surface methodology (RSM) was applied to maximize As(V) removal from aqueous solutions by using modified magnetic nanoparticles with ascorbic acid (AA-MNPs). The structural features of the produced material were characterized by means of X-ray diffraction (XRD), N₂ adsorption–desorption, Fourier transform infrared (FT-IR), vibrating sample magnetometer (VSM), thermogravimetric analyses (TGA), and scanning electron microscopy (SEM). More specifically, the effects of pH, temperature, arsenic ion concentration, and sorbent dosage were investigated on the arsenic adsorption. A total of 20 sets of experiments were designed by the software to achieve maximum adsorption capacity (q ₑ) and removal efficiency (R). Analysis of variance (ANOVA) of the two-factor interaction (2FI) model suggested that the predicted values were in good agreement with experimental data. The best local maximum values for pH, arsenic concentration, and sorbent dosage were found to be 2, 5 mg L⁻¹, and 0.1 g L⁻¹, respectively, that yielding maximum q ₑ of 44.99 mg g⁻¹ and a maximum R of 42.69 %. Additionally, the obtained value for desirability was equal to 0.862. The results indicated that the Langmuir model provided the best correlation of the equilibrium data. Moreover, the obtained results revealed that the pseudo-second-order kinetic model could best describe the adsorption kinetics.

Given the 24-h turn-around time before swimming advisories are released, advisories issued to protect public health really only indicates ‘it may be unsafe to swim yesterday’. Predictive modelling for Escherichia coli concentrations at inflow-impacted beaches may be a favourable alternative to the current, routinely criticised monitoring approach. Using a total of 482 sets of meteorological and bacteriological data covering 14 swimming seasons, as well as environmental data of 10 inflow streams, this study developed models that could be used for predicting E. coli concentrations at five Lake Rotorua beaches. The models include predictor variables such as wind speed, antecedent rainfall, suspended solids at Puarenga, Utuhina and Ngongotaha stream inflows and particulate inorganic phosphorus concentration at Puarenga stream inflow. The combined 2011–2012 models had an average-adjusted R ² of 0.73, root mean square error (RMSE) of 0.33 logCFU/100 mL and captured 38 % of the variance in the validation data when used to predict E. coli concentrations for an additional 2 years (2013–2014). Among the individual beach models, predictive accuracy ranged from 88.89 to 92.31 % for the three beaches considered in the study. The developed models can provide a faster estimation of E. coli condition, potentially assisting local beach managers in the decision process related to swimming advisories issuance.

The potential of natural Chinese zeolite to remove ammonium from rainfall runoff following urea applications to a paddy rice field is assessed in this study. Laboratory batch kinetic and isotherm experiments were carried out first to investigate the ammonium adsorption capacity of the natural zeolite. Field experiments using zeolite adsorption barriers installed at drain outlets in a paddy rice field were also carried out during natural rainfall events to evaluate the barrier’s dynamic removal capacity of ammonium. The results demonstrate that the adsorption kinetics are accurately described by the Elovich model, with a coefficient of determination (R ²) ranging from 0.9705 to 0.9709, whereas the adsorption isotherm results indicate that the Langmuir–Freundlich model provides the best fit (R ² = 0.992) for the equilibrium data. The field experiments show that both the flow rate and the barrier volume are important controls on ammonium removal from rainfall runoff. A low flow rate leads to a higher ammonium removal efficiency at the beginning of the tests, while a high flow rate leads to a higher quantity of ammonium adsorbed over the entire runoff process.

To investigate the effect of different sizes, sex, and exposure time on Cu uptake capacity, mussels Mytilus galloprovincialis of different shell sizes were exposed to different Cu concentrations in different aquariums. In another experiment, mussels were exposed to stable dissolved Cu for 6 days in the laboratory. All mussels tissue concentrations were analyzed using energy dispersive X-ray fluorescence (EDXRF) spectrometry. At the end of uptake, the rate of increase of Cu level in the soft tissues of mussels in different aquariums was 3.84–7.92 times higher than before exposure. While the results of Cu concentrations were negatively correlated with the shell sizes in the control and second groups (r cₒₙₜᵣₒₗ = −0.862, r ₛₑcₒₙd = −0.851 p < 0.05), this relation was not observed in the other groups (p > 0.05). Also, results showed no significant difference between male and female (p > 0.05). On the other hand, Cu concentration values in soft tissue were monitored daily and observed to be increasing up to the third day but afterwards to be descending, thus indicating a significant effect of the exposure time-related Cu uptake by mussels. Therefore, the exposure time to Cu metal of the mussel should be taken into account in the marine pollution investigations. In addition, by using the obtained Cu heavy metal concentration results, the heavy metal intake by the human population was calculated by taking into account daily mussel consumption. The results were examined for potential human health risks and discussed. These results would be helpful to understand factors controlling Cu accumulation in mussels.

Metal oxide nano-particles have definitely unique toxicological properties than currently investigated oxides. Therefore, this study was aimed to comparatively evaluate the genotoxicity of nano-CuO and bulk CuO particles on a model fish species Oreochromis niloticus. Fish were exposed to two selected concentrations (¹/₁₀ and ¹/₂₀ of the LC50/96 h) of both nano-CuO and bulk CuO for 30 days. Genotoxic effects associated with DNA ladder formation and chromosomal damage were investigated using DNA fragmentation and micronucleus techniques. Based on DNA fragmentation of fish hepatocytes, the two selected concentrations of bulk and nano-CuO were found to induce DNA damage. Analysis of the DNA fragments initiated by bulk CuO on agarose gel revealed DNA ladder pattern, which is commonly considered as a hallmark of apoptosis, while fish exposed to nano-CuO particles showed a molecular hallmark of necrosis which is the fragmentation of the nuclear DNA into a smear-like pattern. Also, DNA damage was further confirmed quantitatively using the image analysis software Image J. In this context, nano-CuO-treated groups exhibited a maximum DNA damage especially at the lower concentration (¹/₂₀ LC50/96 h). To ensure CuO genotoxicity, micronucleus and other nine nuclear abnormalities were studied in peripheral erythrocytes and significant (p < 0.05) elevation was observed in nano-CuO-exposed groups at the lower concentration followed by a decrease in extent of chromosomal damage at the higher concentration, while fish groups treated with bulk CuO showed a more or less dose-dependent effect.

The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species.

Chemical cross-linking and the high molecular weight of superabsorbent copolymers (SAPs) are the two main causes of their resistance to biodegradation. However, SAP particles are colonized by microorganisms. For the purposes of this study, the dry technical copolymer of acrylamide and potassium acrylate containing 5.28 % of unpolymerized monomers was wrapped in a geotextile and incubated in unsterile Haplic Luvisol soil as a water absorbing geocomposite. The highest number of soil bacteria that colonized the hydrated SAP and utilized it as the sole carbon and energy source was found after the first month of incubation in soil. It was equal to 7.21–7.49 log₁₀ cfu g⁻¹ of water absorbed by the SAP and decreased by 1.35–1.61 log₁₀ units within the next 8 months. During this time, the initial SAP water holding capacity of 1665.8 g has decreased by 24.40 %. Moreover, the 5 g of SAP dry mass has declined by 31.70 %. Two bacteria, Rhizobium radiobacter 28SG and Bacillus aryabhattai 31SG isolated from the watered SAP were found to be able to biodegrade this SAP in pure cultures. They destroyed 25.07 and 41.85 mg of 300 mg of the technical SAP during the 60-day growth in mineral Burk’s salt medium, and biodegradation activity was equal to 2.95 and 6.72 μg of SAP μg⁻¹ of protein, respectively. B. aryabhattai 31SG and R. radiobacter 28SG were also able to degrade 9.99 and 29.70 mg of 82 mg of the ultra-pure SAP in synthetic root exudate medium during the 30-day growth, respectively.