Bioaccumulation and bioconcentration of metals in Characidae from a Neotropical river basin under anthropic activities.

Natural rates of metal mobilization and deposition in terrestrial and aquatic environments have been changed due to anthropic activities, exposing the native biota to dangerous effects related to bioconcentration and bioaccumulation of metals. This study assessed the concentrations of Cr, Ni, Cd, Pb, Cu, Mn, Co, and Zn in the water and riverbed sediment samples from the Verde River basin (VR), and in tissue samples from two native fishes, the Psalidodon paranae, a VR inhabitant, and the Psalidodon aff. fasciatus, a migratory species. Arithmetic mean values of metal concentrations recorded in waters were Cr: 46.16, Ni: 40.29, Cd 43.19, Pb: 57.74, Cu: 63.72, Mn: 98.36, Co: 64.53, Zn: 81.19, while for riverbed sediments were Cr: 11.84, Ni: 10.52, Cd: 7.14, Pb: 15.00, Cu: 22.16, Mn: 334.77, Co: 24.62, Zn: 434.44. For several analyzed samples, metal concentrations found were higher than Brazilian and international limits set for healthy aquatic life and human uses. Analyzed fish tissues also presented metal concentrations higher than Brazilian and international limits set, indicating a high ecological and health risk for the region. Psalidodon paranae showed affinity to bioconcentrate Pb, Zn, and Cd, while Psalidodon. aff. fasciatus tended to bioconcentrate Ni, Zn, and Cr. Multivariate analyses revealed spatial and temporal patterns in the metal contaminations in VR. These patterns were associated with rural and urban activities developed along VR, which practice inadequate soil handling, indiscriminate use of agrochemicals, and the dumping of domestic garbage and untreated and treated sewage into the river. The implementation of public policies for biomonitoring and pollution control by metals in VR is essential to safeguard regional water resources and their biota.

Effects of different filtration techniques on quality and toxicology of post treatment effluent from an anaerobic reactor.

The early stages of the fish life cycle correspond to the phase that is most susceptible to deleterious effects caused by exposure to pollution. The aim of this study was to evaluate the quality of the anaerobic reactor effluent after three filtration-based treatments, namely, Double-Filtration in gravel and sand (DF), Triple-Filtration in gravel, sand and Activated Charcoal (TF-AC) and Triple-Filtration in gravel, sand and clinoptilolite (TF-C). The toxic effects on the population dynamics of larvae and embryos of catfish (Rhamdia quelen) to the final effluent were evaluated using an individual-based model (IBM). The results indicate that the three post-treatments produced effluents with significant improvement of the physicochemical parameters evaluated in relation to the anaerobic reactor effluent. In addition, all post-treatments improved the removal of metal ions. Experimental data showed high mortality rates for Rhamdia quelen embryos and larvae for most treatments, except for the effluent treated by TF-C. The results demonstrated that the concentration of ammoniacal nitrogen in relation to AR treatments (69.0); DF (44.0); TF-AC (46.6) and TF-C (0.33) in mg/L can be a limiting factor for the development of embryos and larvae during the ecotoxicity tests.

Availability of nutrients, removal of nicotine, heavy metals and pathogens in compounds obtained from smuggled cigarette tobacco compost associated with industrial sewage sludge.

This study evaluated the chemical and microbiological properties of the compost obtained from the tobacco of smuggled cigarettes (SCT) and industrial sewage sludge (ISS). The composting was carried out in three reactors from different combinations of residues. The compost was analyzed to verify the percentage of nicotine removal, heavy metals, nutrient content and the inactivation of pathogenic microorganisms. The concentration of heavy metals: Ni, Cd, Cr, Pb, Cu, Zn, Fe and Mn in the composts obtained from the three reactors was below the values set for their use in soils. The NPK content ranged between 8.31% and 12.43%, indicating that the compost produced can add nutritional benefits to the plants. The nicotine removal, 72.6% (R1), 96.4% (R2) and 99.6% (R3) indicated efficiency of the composting process in reactors in the degradation of this substance. The results of pathogenic microorganism analysis showed that the three composts obtained from reactors R1, R2 and R3 met the sanitation standards for agricultural use according to the normative of maximum limits of contaminants allowed in organic compounds. These results show that the treatment of SCT and ISS by the process of composting in reactors may be an ecologically viable alternative.

Pb2+ adsorption by a compost obtained from the treatment of tobacco from smuggled cigarettes and industrial sewage sludge.

The adsorption of Pb2+ by a compost obtained from the treatment of tobacco from smuggled cigarettes (SCT) and industrial sewage sludge (ISS) was investigated. The Pb2+ adsorption process was evaluated as function of different concentrations of adsorbent and adsorbate, pH variations, and contact time. Fourier transformed infrared spectroscopy (FTIR) and energy dispersive X-ray spectrometry (EDX) were adopted to obtain information regarding structural changes and a better understanding of the adsorption mechanism. The adsorbent maximum adsorption capacity for Pb2+, calculated using the Sips equation, was 21.454 mg/g with 3 g/L adsorbent at pH 5. The adsorption kinetics best adjustment was obtained using the pseudo-second-order model with a time of 240 min to reach the adsorption equilibrium. FTIR and EDX results suggest that Pb2+ might have bonded to phenolic, carboxylic, hydroxyl, and amine groups; they also show formation of organometallic complexes and cationic exchange between the compost and the solution. The study confirmed that the compost evaluated can be used as a potential adsorbent in environments contaminated with Pb2+.

Composting of smuggled cigarettes tobacco and industrial sewage sludge in reactors: Physicochemical, phytotoxic and spectroscopic study.

The maturity of smuggled cigarette tobacco (SCT) and industrial sewage sludge (ISS) compost during composting in reactors was evaluated through physicochemical, phytotoxic and spectroscopic parameters. The temperatures reached peaks above 52 °C in the three reactors and were enough to achieve the stability of the compounds. The electric conductivity was in the optimal interval for farming uses and the pH alkaline band was favorable to produce inorganic nitrogen. The reduction in the C∕N ratio and the increase in cation exchange capacity (CEC) indicated an increase in the compost humification. After 120 days, the seed germination index (SGI) reached 95 % in reactor 3. In the three treatments, the reduction in E2/E6 and E4/E6 ratios (UV/Vis), the increase in humification indices, obtained through FTIR and the aromatic carbon resonance (13C NMR) indicated a high degree of aromaticity. The composting process in reactors was efficient to degrade different proportions of SCT and ISS, resulting in mature composts.