Determination of phytohormones of environmental impact by capillary zone electrophoresis

A test mixture of five phytohormones [naphthaleneacetic acid (NAA), naphthoxyacetic acid (NOA), indoleacetic acid (IAA), indolebutyric acid (IBA), and indolepropionic acid (IPA)] was investigated. These compounds were cleanly separated with good resolution by capillary zone electrophoresis with a UV diode array detector using 20 mM sodium phosphate buffer (pH 7.25). The lowest detection limit was obtained for IPA (0.45 mg L(-)(1) or 0.005 mg kg(-)(1)) and the highest for NAA (1.04 mg L(-)(1) or 0.014 mg kg(-)(1)). The method has been applied for tomato samples fortified with the five phytohormones using a liquid-liquid extraction procedure, obtaining recovery percentages ranging from 91 to 109.0%.     

Occurrence and infectivity of arbuscular mycorrhizal fungi in some norwegian soils influenced by heavy metals and soil properties

Mycorrhizae are ubiquitous symbiosis which can mediate uptake of some plant nutrients. In polluted soils they could be of great importance in heavy metal availability and toxicity to plants. Mycorrhizae have also been reported to protect plants against toxic metals. We investigated the occurrence and infectivity of arbuscular mycorrhizal (AM) spores as affected by heavy metal levels and other soil properties in Norwegian soils collected from heavy metal polluted, high natural background and non-polluted areas. Spore numbers, mycorrhizal infectivity and spore germination of indigenous mycorrhizal fungi and of a reference strain (Glomus mosseae) in soils showed lower values in two soils with high metal concentrations and in one soil with a low pH. Mycorrhizal infectivity was negatively correlated with extractable metals. Spore number and mycorrhizal infectivity in a soil with naturally high heavy metal content were not different to in non-polluted soils, and indigenous AM fungi appeared more tolerant to metals than those in non-polluted soils. Mycorrhizal infectivity, expressed as MSI₅₀ values, was significantly correlated (r′=0.89, P< 0.05) with the percentage of germinating G. mosseae spores in the soils. However, the number of spores per volume of soil was not significantly correlated with infectivity or spore germination of the reference strain. The spore germination method is discussed as a bioassay of heavy metal toxicity in soil.     

Design of Optimum Response Surface Experiments for Electro-Coagulation of Distillery Spent Wash

Electro-coagulation (EC) of a distillery spent wash has been optimized by Box–Behnken design of surface response analysis in terms of color removal. The design was employed to derive a statistical model for the effect of parameters studied on removal of color using iron anodes. The current density (31 mA/cm²), dilution (17.5%) and time of electrolysis (4 hours) had been found to be the optimum conditions for maximum 95% color removal. The actual color removal at optimized conditions was found to be 93.5% which confirms close to the predicted response using response surface methodology.     

Bottled-Water Quality in Metropolitan Mexico City

Bacteriological and physico-chemical parameters of 265 samples from 39 brands sold in 5-gallon plastic and glass bottles and 2-5 L plastic containers were analyzed to determine the quality of bottled water distributed in Mexico City. Tests included fecal and total coliform counts, alkalinity, total hardness, chloride, calcium and magnesium concentrations, pH and conductivity. Correlation and cluster analyses and ANOVA were carried out, and a comparison made of the averages with the maximum permissible levels established in the Official Mexican Norms. Concerning the investigated parameters no differences (p > 0.05) between the brands were found. Physico-chemical parameters were studied and all the samples were within the permissible limits. Most samples taken from the 5-gallon containers exceeded the maximum bacteriological limits. It was concluded that the bacteriological quality of the brands studied was extremely variable. Appropriate sanitary measures, should be established to control this aspect.     

Lipid Extraction from Wheat Flour Using Supercritical Fluid Extraction

Environmental concerns, the disposal cost of hazardous waste, and the time required for extraction in current methods encouraged us to develop an alternate method for analysis of wheat flour lipids. Supercritical fluid extraction (SFE) with carbon dioxide has provided that medium and the method is fully automatic. Crude fats or nonstarch free lipids (FL) were extracted from 4–5 g of wheat flour by an SFE system. To develop optimum conditions for SFE, various extraction pressures, temperatures, and modifier volumes were tried to provide a method that would produce an amount of lipids comparable to those extracted by the AACC Approved Soxhlet Method and the AOCS Official Butt Method using petroleum ether as solvent. Using several wheat flour samples, the best conditions were 12.0 vol% ethanol (10.8 mol%) at 7,500 psi and 80°C to extract the amount of FL similar to those by the AACC and AOCS methods. Using solid‐phase extraction, lipids were separated into nonpolar lipid (NL), glycolipid (GL), and phospholipid (PL) fractions. The mean value of five flours was 1.15% (flour weight, db) by the SFE method, 1.07% by the Butt method, and 1.01% by the Soxhlet methhod. The SFE‐extracted lipids contained less NL and more GL than either the Butt or Soxhlet methods. All three methods extracted lipids with qualitatively similar components. The overall benefit for SFE over the Soxhlet or Butt methods was to increase the number of samples analyzed in a given time, reduce the cost of analysis, and reduce exposure to toxic chemicals.     

Aggregate associated carbon, nitrogen and sulfur and their ratios in long-term fertilized soils

Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka⁻¹ and high level of 60 Mg ka⁻¹) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1–2 mm) and microaggregates (<0.106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5–1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5–1 and <0.106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher C/N, C/S and N/S ratios were found both in large dry aggregates (>20 and 6–20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0.106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered.     

Soil amendment with city sewage sludge increases soil extractable cadmium,nickel and zinc more than tannery,pharmaceutical and paper mill wastes

Abstract

The distribution of DTPA-extractable Cd, Ni and Zn in four profile samples collected from areas contaminated with wastes from tannery, city sewage, pharmaceutical and paper mills located at different places in Bangladesh was investigated. Soil samples were analysed for the total and their DTPA-extractable metal contents. The total concentration of metals in the soil horizons ranged from 0.07 to 0.62 mg kg^?1 for Cd, 31 to 54 mg kg^?1 for Ni and 59 to 838 mg kg^?1 for Zn, respectively. These metal concentrations were highest in the surface and lowest in the subsurface horizons. This trend was also observed for the DTPA-extractable amounts of these metals. The relative extractability, expressed as the ratio of DTPA to total contents (aqua regia-extractable) was 33 to 46% for Cd, 2 to 10% for Ni and 3 to 28% for Zn, respectively, in the A1 horizon, while in the B and C horizons the ratios decreased gradually as did total concentration, indicating that metal contamination was primarily limited to the surface horizon. For all three metals, the above mentioned ratio was highest in the city sewage soil and the lowest in the paper mill soil. In general, the extent of contamination among the profiles investigated was in the following order: city sewage>tannery>pharmaceutical>paper mill soil. Higher ratios of DTPA-extractable Cd, Ni and Zn in the city sewage soil than the other soils may create a risk for the contamination of agricultural products and ground water.