Hybrid constructed wetlands for the treatment of wastewater from a fertilizer manufacturing plant: Microcosms and field scale experiments.

Wastewater from a fertilizer manufacturing plant requires improvement prior to its environmental disposal. Ammonium is the critical contaminant to be removed. The aim of this study was to evaluate the feasibility of using free water surface wetlands (FWSWs), horizontal subsurface flow wetlands (HSSFWs), and their combination in hybrid wetlands (HWs) for the final treatment of wastewater with high ammonium concentration from a fertilizer manufacturing plant. Substrates and macrophytes were evaluated in microcosm experiments during three months. There were no significant differences in contaminant removal among HSSFWs with LECA or FWSWs planted with Typha domingensis or Canna indica. In a second stage, two configurations of pilot-scale HWs were constructed at the manufacturing facilities. Configuration A: HSSFW(A1)-FWSW(A2) and Configuration B: FWSW(B1)-HSSFW(B2) were evaluated during 12 months. There were no significant differences in contaminant removal (%) between the two configurations of HWs for COD (A: 74.5 ±â€¯12.2/B: 81.5 ±â€¯9.4), ammonium (A: 59.5 ±â€¯17.5/B: 57.9 ±â€¯21.4), nitrite (A: 79.8 ±â€¯24.2/B: 80.6 ±â€¯16.8) and dissolved inorganic nitrogen (DIN) (A: 59.4 ±â€¯17.3/B: 50.3 ±â€¯24.4). However, nitrate concentration (9.83 ±â€¯3.11 mg N L-1) was significantly lower after Configuration A than after Configuration B (18.8 ±â€¯5.2 mg N L-1). Comparing FWSWs and HSSFWs, they did not present significant differences in ammonium removal, while FWSWs presented the highest DIN removal. T. domingensis and C. indica in HSSFWs and T. domingensis in FWSWs tolerated wastewater conditions. T. domingensis presented the highest productivity. In further research, FWSWs in series planted with T. domingensis should be studied.

Physiological and biochemical responses of Eichhornia crassipes exposed to Cr (III).

The effect of exposure of Eichhornia crassipes to Cr (III) was assessed by measuring changes in photosynthetic pigments, malondialdehyde, superoxide dismutase, glutathione reductase, catalase, and guaiacol peroxidase activities, as well as Cr concentration in tissues. Cr concentration in roots was significantly higher than in aerial parts and increased with Cr concentration in water. Photosynthetic pigments increased significantly, whereas the activities of antioxidant enzymes varied differently in plant tissues. Low Cr concentrations induced a rapid response of E. crassipes during short-term exposure, implying that the antioxidant system conferred redox homeostasis. Results showed that Cr (III) was more toxic at the two highest concentrations and long-term exposure, while it was not harmful but beneficial at the two lowest concentrations and short-term exposure. This work concludes that E. crassipes was able to grow under Cr (III) stress by protecting itself with an increase in the activity of its antioxidant system.

Improvement of Cr phytoremediation by Pistia stratiotes in presence of nutrients.

The effects of different concentrations of P and N, added separately or combined, on the Cr(III) accumulation capacity of P. stratiotes were studied. Plants and pond water with the addition of contaminant(s) were placed in plastic aquaria. Cr concentration was 5 mg L(-1), while P and N concentrations were 5 mg L(-1) or 10 mg L(-1). Nutrient addition significantly favoured Cr removal and enhanced Cr translocation to leaves. In Cr treatments a high detritus formation from loss of root biomass was observed probably due to its toxicity. Cr was mainly accumulated in the detrital fraction, whereas P and N were retained fundamentally in leaves. A toxic effect was observed in the Cr + P10 and Cr + N10 treatments. These results could be applied to enhance Cr removal efficiency of constructed wetlands using P. stratiotes, where nutrient enrichment could be attained by treating sewage together with the industrial effluents.

Sustainability of a constructed wetland faced with a depredation event.

A free water surface constructed wetland (CW) designed for effluent treatment was dominated by the emergent macrophyte Typha domingensis reaching a cover of roughly 80% for 5 years. Highly efficient metal and nutrient removal was reported during this period. In June 2009, a population of approximately 30 capybaras (Hydrochoerus hydrochaeris) caused the complete depredation of the aerial parts of macrophytes. However, plant roots and rhizomes were not damaged. After depredation stopped, T. domingensis showed a luxuriant growth, reaching a cover of 60% in 30 days. The objective of this work was to evaluate the sustainability of the CW subjected to an extreme event. Removal efficiency of the system was compared during normal operation, during the depredation event and over the subsequent recovery period. The CW efficiently retained contaminants during all the periods studied. However, the best efficiencies were registered during the normal operation period. There were no significant differences between the performances of the CW over the last two periods, except for BOD. The mean removal percentages during normal operation/depredation event/recovery period, were: 84.9/73.2/74.7% Cr; 66.7/48.0/51.2% Ni; 97.2/91.0/89.4% Fe; 50.0/46.8/49.5% Zn; 81.0/84.0/80.4% NO3(-); 98.4/93.4/84.1% NO2(-); 73.9/28.2/53.2% BOD and 75.4/40.9/44.6% COD. SRP and TP presented low removal efficiencies. Despite the anoxic conditions, contaminants were not released from sediment, accumulating in fractions that proved to be stable faced with changes in the operating conditions of the CW. T. domingensis showed an excellent growth response, consequently the period without aerial parts lasted a few months and the CW could recover its normal operation. Plants continued retaining contaminants in their roots and the sediment increased its retention capacity, balancing the operating capacity of the system. This was probably due to the fact that the CW had reached its maturity, with a complete root-rhizome development. These results demonstrated that faced with an incidental problem, this mature CW was capable of maintaining its efficiency and recovering its vegetation, demonstrating the robustness of these treatment systems.

P distribution in different sediment fraction of a constructed wetland.

The aim of this work was to study the accumulation and fractionation of P in the inlet and outlet sediment of a constructed wetland for the wastewater treatment of a metallurgic plant in Argentina. It was important to predict whether P could be released into the water again by changing environmental conditions or retained over time. P-fractionation was performed using a sequential extraction method. Sediment cores were sliced at depths of: 0-3; 3-7 and 7-10 cm. Sediment showed high pH values and anoxic conditions. In the inlet area, P was principally bound to the carbonate fraction, whereas in the outlet area, it was mainly bound in the residual fraction. This behavior was justified by the effluent composition, which is rich in Ca2+ and Fe3+ and presents high values of pH and conductivity. These conditions favor CaCO3 and Fe(OOH)n precipitation and the subsequent sorption of P to their surface. The sediment active layer involved in the exchange reactions was the superficial one (0-3 cm). The wetland is highly efficient in P retention. P was retained by sediment in fractions that will not release it to the water while chemical and environmental conditions of the system are maintained.

Anti-diabetic potentials of Momordica charantia and Andrographis paniculata and their effects on estrous cyclicity of alloxan-induced diabetic rats.

Momordica charantia and Andrographis paniculata are the commonly used herbs by the diabetic patients in Pampanga, Philippines. While the anti-diabetic potential of Momordica charantia is well established in streptozocin- or alloxan-induced diabetic animals, the anti-diabetic potential of Andrographis paniculata in alloxan-induced diabetic rat is not known. Neither the effects of these herbs on estrous cyclicity of alloxan-induced diabetic rats are elucidated. Thus, in these experiments, Momordica charantia fruit juice or Andrographis paniculata decoction was orally administered to alloxan-induced diabetic rats. Rats that were treated with Momordica charantia and Andrographis paniculata had higher body weight (BW) compared with diabetic positive control (P < 0.01) from day 22 to day 27 (D27) but exhibited lower BW than the non-diabetic control (P < 0.05). These rats had lower feed (P < 0.05) and liquid intakes (P < 0.01) compared with diabetic positive control from day 17 to D27, but similar with the non-diabetic control. The blood glucose levels in these groups were significantly reduced from day 12 to D27 compared with diabetic positive control (P < 0.01), however, comparable with non-diabetic control. The diabetic positive control had extended mean estrous cycles (8 days) compared to Momordica charantia and Andrographis paniculata-treated diabetic rats (5 days; P < 0.05). Our results suggest that the anti-diabetic potentials of Momordica charantia and Andrographis paniculata could restore impaired estrous cycle in alloxan-induced diabetic rats.

[Structural characteristics of prolactin, growth hormone and their receptors as determinants of biological actions]. / Características estructurales de la prolactina, la hormona de crecimiento, y sus receptores como determinantes de la acción biológica.

The pituitary hormones prolactin and growth hormone are structurally related. Both hormones exist in the circulation in several molecular forms, differing in aminoacid sequences, posttranslational modifications and fragments produced by proteolytic cleavage. Heterogencity may produce a diversity of inmunological and biological actions. It has been suggested that each of this forms may be a isohormone with a different physiological role. The predominance of one of them in serun could account for the complex and often contradictory actions of the hormones. In addition receptors also have structural homology and so the possibility exist that these hormones share binding affinity to the receptors and can produce endocrinological problems in some special conditions.

[Colorimetric and opacity percentage study of dental restorative resins]. / Estudio colorimétrico y de porcentaje de opacidad en resinas dentales de restauración.

A colorimetric and opacity percentage study was carried out to compare experimental prototypes of resin at different die and additive concentrations with commercial prototypes. A simple and reproducible method was used. Through this study the optimum die and optical brightener formulas for a new dental resin were found and compared with available commercial dental resins in the national market.

[Physical behavior of 5 autopolymerizing dental resins]. / Estudio del comportamiento fisico de cinco resinas dentales autopolimerizables.

The Tests described in the American Dental Association Standard No. 27 were carried out with five commercial dental resins available in mexican market. These are: Adaptic, Concise, Miradapt, Degufill and Finesse. Two of them are of the macrofilled type (II), one is of the hybrid type (mix of macro and micro particles; type II) and two of the microfilled type (I). All the resins tested met satisfactorily the specifications of the A.D.A. standard No. 27 for dental componsed resins, according with their classification.

A comparison between clinical diagnosis and histopathological findings in liver biopsies.

In 70 consecutive patients the histopathological diagnosis of needle liver biopsy specimens and the clinical diagnosis were compared. The patients were divided into the following groups: alcoholic liver disease, hepatitis, malignancy, cholestasis, and miscellaneous. Nearly half of the cases were alcohol-induced; all of these showed changes in the specimens consistent with an elevated alcohol consumption, but their histopathological 'severity' did not correlate with the amount of alcohol consumption. In the hepatitis group three cases of acute viral hepatitis gave identical clinical and histopathological diagnoses. The malignancy group showed that in five of eight cases the needle biopsy specimen confirmed the clinical suspicion of malignant tumour in the liver. The histopathological diagnoses of the miscellaneous group were not able to add further information to the clinical findings because of unspecific lesions in the specimens. Two specimens were taken from each patient, and the 'reproducibility' of the histopathological diagnoses of the interdependent specimens showed a high degree of agreement: 71% of the biopsy pairs had identical diagnoses of the two specimens from the same patients, and 12% of the biopsy pairs had only small differences between the two diagnoses.

The variation of pathological changes in the liver evaluated by double biopsies.

In two simultaneously-taken needle biopsies of the liver from 70 consecutive patients, a number of changes were evaluated semiquantitatively and compared in n x m tables. The lesions examined were steatosis, Mallory's hyalin, alcoholic hepatitis, cirrhosis and cholestasis; furthermore the size, amount of inflammatory cells, connective tissue and bile-duct proliferation of the portal tracts and finally focal necroses and acidophilic bodies in the lobules were recorded. Cirrhosis, cholestasis and steatosis showed a high correlation, while the agreement between the two interdependent biopsies, especially concerning acidophilic bodies and bile-duct proliferation, was low. Possible reasons for the variation in the agreement of the lesions are discussed.