Bioaccumulation of metals in Spartina alterniflora salt marshes in the estuary of the World's Largest Choked Lagoon.

Salt marshes are capable of mitigating metal pollution in coastal environments, yet the efficacy of this remediation is contingent upon various environmental factors and the plant species involved. This study investigates the influence of different anthropogenic activities, including industrial, urban, recreational (in an insular area), and dredging operations, on the bioaccumulation of eight metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) within Spartina alterniflora Loisel. in the Patos Lagoon estuary, Brazil. The research aims to assess the pattern of metal bioaccumulation and distribution within the plant's leaves, stems, and roots while also examining metal presence in the sediment. Our main findings reveal that S. alterniflora exhibited elevated metal levels in its plant structure directly related with the metal concentrations in the surrounding sediment, which, in turn, is related to the different anthropogenic activities. The industrial area presented the highest metal levels in sediment and plant sections, followed by dredging, insular, and urban areas. This same pattern was mirrored for the bioconcetration factors (BCF), with the BCFs consistently indicating active metal bioaccumulation across all areas and for most of the metals. This provides evidence of the metal bioaccumulation pattern in S. alterniflora, with elevated BCFs in areas affected by activities with a higher degree of impact. Translocation factors (TF) showed varying metal mobility patterns within the plant's below-ground and above-ground sections across the different areas, with only Hg exhibiting consistent translocation across all study areas. Zn was the primary metal contributor in all plant sections, followed by Pb and Cu. It is worth noting that Pb is a non-essential metal for this plant, highlighting the relationship between elevated Pb contributions in the plant sections and the bioaccumulation of this metal within the plant's structure. Overall, this study emphasizes the bioaccumulation capacity of S. alterniflora and elucidate the intrinsic connection between different anthropogenic activities and their impact on the resultant availability and bioaccumulation of metals by this salt marsh plant.

Multiple exposure pathways and health risk assessment of potentially harmful elements for children and adults living in a coal region in Brazil.

Energy generated by coal can contaminate the environment by releasing toxic elements, including metals. The human health risk assessment (HHRA) associated with geographic information system (GIS) tools can assist the management of contaminated areas, such as coal mining areas. The objective of the study was to carry out the assessment and spatialization of the risk to human health of potentially hazards elements (PHEs) in the soil for children and adults, from multiple exposure routes (oral, inhalation and dermal) in the Candiota mines, largest coal mining region of Brazil. The non-carcinogenic risks (HQ) of PHEs (Cu, Pb, Zn, Ni, Cr, Fe, Mn, Cd, As and Se) and carcinogenic risks of As were estimated and spatialized. The results revealed a risk for children exposure to Mn, with greatest contribution through dermal route. Mn (HQderm 72.41-96.09% and HQinh 40.84-82.52%) and Fe (HQo 43.90-81.44%) were the metals with greatest contribution to human health risk among studied population. As did not present carinogenic risk to adults. The spatial distribution of non-carcinogenic risk showed that Cr, As, Fe, Pb, Ni, Zn and Cu have higher HInc close to the coal mining areas, while Mn, Se and Cd have the highest HInc values in surrounding municipalities (Pinheiro Machado; Pedras Altas and Hulha Negra). The use of HHRA associated with GIS tools provides important elements for decision-making in the management of contaminated sites, indicating chemical elements, locations, routes of exposure and priority target populations.

Utilization of sludge derived from landfill leachate treatment as a source of nutrients for the growth of Nicotiana alata L.

The sludges derived from the leachate treatment (LS) represent an important environmental and operational problem in the landfill management. On the other hand, they can be utilized as an alternative source of nutrients and organic matter. The main objective of this work was to evaluate the reuse of the LS of a sanitary landfill in Santa Fe city - Argentina, as an organic amendment for the development of Nicotiana alata L. plants. Different doses of LS were applied to a soil mixture for potted seedling growth. The response surface methodology was applied, using a one-factor design. Once the phenological stage of flowering began, the plants were harvested. Physiological and biochemical determinations were made in order to evaluate the effects of the different amendments. Application of LS notably improved growth parameters such as stem height, leaf area and dry matter. Additionally, the content of proteins and photosynthetic pigments was enhanced. Through the multiple regression statistical analyses, the relationship between the response variables and the sludge content was established. The multivariate optimization analysis yielded 53% as the optimal sludge content. Our results indicate that this sludge, in appropriate doses, can be used as an organic amendment for the revegetation of sanitary landfills.

Degradation and mineralization of the emerging pharmaceutical pollutant sildenafil by ozone and UV radiation using response surface methodology.

Pharmaceuticals and their degradation products which are present in wastewater and superficial waters are becoming an ecological issue. This research investigated the degradation and mineralization of synthetic solutions of the pharmaceutical compound sildenafil citrate (SC) by single ozonation and ozonation jointed with UV radiation (O3/UV). The effects of initial drug concentration (50-125 mg L-1), inlet ozone concentration (35-125 g Nm-3), and UV radiation on SC degradation and decrease of total organic carbon (TOC) were investigated using response surface methodology based on a central composite experimental design. Through the RSM analysis, it was possible to confirm the removal of SC for the entire experimental range. Major intermediates of SC degradation were identified and a degradation pathway was proposed. The kinetics of SC degradation was modeled as a pseudo-first-order reaction with a rate constant ranging between 0.072 and 1.250 min-1. The SC degradation and TOC removal were strongly enhanced by increasing the concentration of gaseous ozone at the inlet and incorporating UV radiation. The highest TOC removal reached at 60 min was 75%, in the O3/UV system, with initial SC content of 50 mg L-1 and inlet ozone concentration of 125 g Nm-3. The degradation rate of SC was increased 3 to 9 times in the presence of UV radiation. Ozone-based advanced oxidation processes appear as a suitable alternative for treatment of the emerging pollutant SC.