Activity of nitrate reductase and the content of proteins in Nicotiana rustica grown with various levels of molybdenum

The effect that different levels of molybdenum (11 μMand 111 μM) exert on nitrate reductase (E.C. 1.6.6.1–3) activity (NRA), and the content of total proteins in Nicotiana rustica was studied. Eleven μM and 111 μM of molybdenum increased the activity of nitrate reductase during the growth cycle of N. rustica. Likewise, total protein content (mg/g DW) was increased during the vegetative growth of the plants.     

Dissolved and Particulate Heavy Metals in the Salado River (Santa FE, Argentina)

The objective of this work is to analyze Fe, Mn, Cr, Cd, Cu, Pb, and Zn distributions in the water column in terms of total, dissolved, and particulate concentrations in the Salado River (Santa Fe – Argentina); their relationship with total, dissolved and suspended solids; and the impact of two pollution sources on the watercourse: a stream that collects domestic and industrial wastewater discharges of the region and a direct discharge that releases urban and industrial effluents to the river. Water samples obtained from 5 surveys were analyzed. The Salado River transported a load of heavy metals that ranged from 700 g/s to 2200 g/s of Fe, 20 g/s to 60 g/s of Mn and 1 g/s to 3 g/s of Cr. Results show that most metals were found in particulate form, that the metal input from the direct discharge may be significant at low water levels, whereas a lesser impact was produced by the stream, and that both pollution sources were negligible at high water levels.     

Geochemistry of Aluminium and Iron in Mine Soils from As Pontes,Galicia (N.W. Spain)

The geochemical processes influencing iron and aluminium mobilization and immobilization processes in mine soils are discussed. The study was carried out on 11 soils from the As Pontes mine dump, in the process of reclamation. The soils differ in age, spoils nature, reclamation tasks and type of vegetation, covering a wide range of physico-chemical conditions. Oxalate and pyrophosphate extractable Al and Fe (Alo, Alp, Feo, Fep), and dithionite extractable Fe (Fed) were analysed. These fractions were related to the solution Al and Fe forms and contents and to other soil properties (Eh, pH, sulfides, organic matter, cation exchange capacity, and composition of the soil solution). Alo ranged between 2.2 and 111.2 cmolc kg-1; 5 to 80% of this Alo was organic aluminium (Alp). Fed ranged between 8.5 and 215.6 cmolc kg-1; 20 to 70% was poorly-criystalline iron (Feo). The solution concentrations of Al and Fe ranged between <0.1 and 319.2, and between <0.1 and 46.7 mg L-1, respectively. The results showed that the spoil nature (mostly carbonaceous clays and slates differing in sulfide content) and the reclamation tasks undertaken (topsoiling, liming with fly ash) determine the forms and contents of Al and Fe in the solid phase as well as in the soil solution and also its distribution between the solid and liquid phases.     

Sensitivity of Soil P Availability Tests to Ca-P in Oxisols

We assessed the sensitivity of mixed exchange resin (MER) and Mehlich-3 (M3) to calcium-bound phosphate (Ca-P) in Oxisols. These methods were compared with Mehlich-1 (M1) and anion exchange resin (AER), which have high and low sensitivity, respectively, to this soil P form. We used maize (Zea mays L.) as a test plant. Three samples from two Oxisols were treated with five ratios of Triple Superphosphate—TS and Bayóvar Phosphate Rock—BPR (0 + 100; 25 + 75, 50 + 50, 75 + 25 and 100 + 0% TS + BPR). The MER extracted more P than AER and M3 at the highest BPR:TS ratios (high Ca-P) and similar quantities at the higher TS:BPR ratios (low Ca-P) for two soil samples. Unlike M1-extracted P, M3-P, AER-P, and MER-P positively correlated with maize dry matter production and P uptake. Mehlich-3 and MER were suitable to assess P availability in high Ca-P Oxisols.     

A simplified spectrophotometric method for routine analysis of saccharin in commercial noncaloric sweeteners

A simple, rapid, and sensitive spectrophotometric method for routine analysis of saccharin in commercial noncaloric sweeteners is proposed. This method is based on the reaction of saccharin with tetrachloro-p-benzoquinone (p-chloranil) accelerated by hydrogen peroxide and conducted in an ethanol:acetone (4:1) medium, producing a violet-red compound (lambda(max) = 550 nm). Beer's law is obeyed in a concentration range of 2.05 x 10(-4) to 3.00 x 10(-3) M with an excellent correlation coefficient (r = 0.9998). The detection limit was 1.55 x 10(-5) M, and the effect of interferences on the spectrophotometric measurements was evaluated. The proposed procedure was applied successfully to the determination of saccharin in noncaloric sweeteners. Recoveries were within 99.2-104.3% with standard deviations ranging from to 0.5-1.6%. Results of the proposed method compare very favorably with those given by the high-performance liquid chromatography method recommended by the Food and Drug Administration.     

Human activities modify soil properties in urban parks: a case study of Tel Aviv-Jaffa

Purpose

The aim of the present study was to investigate the effects of visitors’ activities on soil properties in parks of Tel Aviv-Jaffa city, Israel.

Materials and methods

The city was divided into three geographical regions: south, central, and north. This division reflects the course of development of the city from south to north and encompasses various socioeconomic levels of residents. In each region, 9–15 parks were randomly chosen and classified into three groups according to their size (in m²): 2?×?10³ to 10?×?10³, 11?×?10³ to 20?×?10³, and 21?×?10³ to 50?×?10³. In each park soil, 0–2 cm of depth layer was sampled in areas under various levels of visitor pressure from July to August 2011, and organic matter, electrical conductivity, and sodium and chlorine contents were determined. Lawns and path and picnic areas represented low and high visitor pressure, respectively. Observations were conducted to characterize the various land uses of the parks and to estimate the numbers of visitors. Also, questionnaires were used at selected parks to assess visitors’ motivations or reasons for visiting the parks.

Results and discussion

Socioeconomic indicators, such as the number of residents, the apartment areas, and the percentages of family households, differed among the regions. Soil properties differed between the areas of high and low visitor pressure: they were influenced by type of human activity, size of the park, and number of visitors.

Conclusions

Soil properties are affected by variations in the intensity of park use by visitors and by the type of activities enjoyed by these visitors, both of which depend on the socioeconomic status of the park area.

     

HPLC separation and determination of 12 cholesterol oxidation products in fish: comparative study of RI, UV, and APCI-MS detectors

A simple, fast, and sensitive method for the extraction through direct saponification, separation, quantification, and identification of 12 cholesterol oxidation products (COPs) and cholesterol in a single isocratic, normal-phase, high-performance liquid chromatography (HPLC) was developed. Three detectors were compared for determination of COPs and cholesterol in fish samples: refractive index (RI), ultraviolet (UV), and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The results did not show significant differences (p > 0.05) between the concentration of the cholesterol oxides and cholesterol obtained with these detectors. The present study demonstrated the presence of 19-hydroxycholesterol, 22"R"-hydroxycholesterol, 22"S"-hydroxycholesterol, 24"S"-hydroxycholesterol, and 25"R"-hydroxycholesterol for the first time in fish samples.     

Influence of automatic dishwashings and scrubbings on release of lead from glazed ceramicware

Use of lead glazes on ceramicware and the release of lead from finished glazes are reviewed. Single units of ceramicware with initial lead leach levels from less than 0.1 to 470 micrograms/mL were subjected to multiple automatic dishwashings with intermediate scrubbing of the ware by plastic fiber pads. Ware was periodically leached with 4% acetic acid solution at room temperature for 24 h, and the solutions were analyzed for lead. Release of lead under these conditions is discussed. Results indicated that neither passive leachings nor multiple dishwashings and scrubbings can predict future lead-release characteristics of glazes and decorations.