Distribution Of Different Fractions Research Articles

Distinctive Accumulation Patterns of Trace Elements in Sediments of Bedrock Rivers (Miño River, NW Iberian Peninsula)

Sediment compositions and enrichment patterns are investigated in an urban reach of a bedrock river, the Miño River passing through Ourense City, Spain. This study focuses on the trace element distribution in different fractions to gain insights into trace element enrichment. To assess enrichment, a context-specific approach was employed, based on the mean, the standard deviation of the estimated background, and the empirical rule, avoiding the pitfalls of general and arbitrary thresholds. Notably, the <0.063 mm and <2 mm fractions showed differential accumulation patterns. Both fractions serve to detect enrichments that can be indicative of contamination, but they measure different things, the maturity of sediments and postdepositional processes being key factors in understanding the sediment composition and enrichments. These findings also highlight the role of rock cavities, particularly those hosting permanent deposits, as traps for trace elements and their potential significance in assessing environmental enrichment. This work contributes to understanding sediment compositions and enrichment dynamics in bedrock rivers. It also underscores the significance of considering site-specific approaches for enrichment assessment and the necessity for further research to unravel the mechanisms driving differential accumulation within distinct depositional environments.

Recent Advances in the Decontamination and Upgrading of Waste Plastic Pyrolysis Products: An Overview

Extensive research on the production of energy and valuable materials from plastic waste using pyrolysis has been widely conducted during recent years. Succeeding in demonstrating the sustainability of this technology economically and technologically at an industrial scale is a great challenge. In most cases, crude pyrolysis products cannot be used directly for several reasons, including the presence of contaminants. This is confirmed by recent studies, using advanced characterization techniques such as two-dimensional gas chromatography. Thus, to overcome these limitations, post-treatment methods, such as dechlorination, distillation, catalytic upgrading and hydroprocessing, are required. Moreover, the integration of pyrolysis units into conventional refineries is only possible if the waste plastic is pre-treated, which involves sorting, washing and dehalogenation. The different studies examined in this review showed that the distillation of plastic pyrolysis oil allows the control of the carbon distribution of different fractions. The hydroprocessing of pyrolytic oil gives promising results in terms of reducing contaminants, such as chlorine, by one order of magnitude. Recent developments in plastic waste and pyrolysis product characterization methods are also reported in this review. The application of pyrolysis for energy generation or added-value material production determines the economic sustainability of the process.

Bioactive Compounds and Antioxidant Activities in Different Fractions of Mango Fruits (Mangifera indica L., Cultivar Tommy Atkins and Keitt).

This study aims to describe and compare the distribution of bioactive compounds, the fatty acids profiles, and the TEAC hydrophilic and lipophilic antioxidant activities in different fruit fractions (pulp, peel, and kernel) of two mango cultivars (Tommy Atkins and Keitt). All fractions are sources of health-promoting bioactive compounds. Regardless of cultivars, pulp had the highest content of phytosterols (~150 mg/100 g dw), peels ranked first for pentaciclic triterpenes (from 14.2 to 17.7 mg/100 g dw), tocopherols, carotenoids, and chlorophylls, and kernels for phenolic compounds (from 421.6 to 1464.8 mg/100 g dw), flavonoids, condensed tannins, as well as hydrophilic and lipophilic antioxidant activities. Differences between the two cultivars were evidenced for ascorbic acid, which showed the highest levels in the peels and kernels of Keitt and Tommy Atkins fruits, respectively. Similarly, the concentration of dehydroascorbic acid was higher in the pulp of Tommy Atkins than Keitt. The highest percentage of saturated fatty acids was observed in pulp (~42%) and kernels (~50%), monounsaturated fatty acids in kernels (up to 41%), and polyunsaturated fatty acids in peels (up to 52%). Our results add information to the current knowledge on nutraceuticals’ distribution in different fractions of mango fruit, supporting its consumption as a healthy fruit and suggesting the great potential value of peels and kernels as sources of novel ingredients. Indeed, mango by-products generated during agronomic-to-industrial processing not only causes a significant environmental impact, but economic losses too. In this scenario, boosting research on conventional recovery methods offers eco-friendly solutions. However, green, novel biorefinery technologies may offer eco-friendly and profitable solutions, allowing the recovery of several more profitable by-products, sustaining their continuous growth since many bioactive compounds can be recovered from mango by-products that are potentially useful in the design of innovative nutraceutical, cosmeceutical, and pharmaceutical formulations.

Manganese availability and transformations in soil profiles under different wheat based cropping systems in north-western India

We studied the depth-wise distribution of DTPA-Mn and Mn fractions of variable solubility in soils under three different cropping systems viz. rice-wheat (RWCS), maize-wheat (MWCS) and cotton-wheat (CWCS) in Punjab, north-western India. The surface (0-15cm) layer of soils under RWCS had significantly lower (by ~31.8%) DTPA-Mn concentration, compared with MWCS. The surface soils under CWCS had ~18.4% higher DTPA-Mn than the soils under RWCS. The DTPA-Mn increased significantly with increased depth of soils under RWCS, in contrast to a significant decrease in MWCS and CWCS. A sequential extraction of Mn in different fractions of variable solubility revealed that the surface layer of soils under RWCS had significantly lower concentration, while the lower layers had higher concentration. On the other hand, the surface layer of soils under MWCS and CWCS had significantly higher concentration, which decreased with increased soil depth. The Res-Mn fraction comprised the largest proportion (67-70%) of total-Mn in soils under different cropping systems. The (WSEX+SpAD)-Mn fraction were the smallest Mn fraction of high solubility, comprising ~2-3% of total-Mn in soils under different cropping systems. The relative distribution of different fractions followed: OM-Mn ≤ WSEX-Mn ≤SpAD-Mn <AFeOX-Mn <CFeOX -Mn < Ox-Mn < residual-Mn.

Flow of arsenic between rice grain and water: Its interaction, accumulation and distribution in different fractions of cooked rice

Arsenic (As) contaminated water is a major threat to human health when used for drinking, cooking and irrigational purposes. Rice being consumed by 50% of the world's population, supplies considerable amount of As to the human body. Our study provides a detailed understanding of As distribution in each fraction of rice while cooking (viz. uncooked rice, cooking water, cooked rice and gruel/total discarded water), ultimately leading to a better explanation of As movement between rice grain and water. A significant decrease of As was observed in cooked rice (34–89% and 23–84% for sunned and parboiled rice respectively) when cooked with low-As containing water, <3 μg/l and moderate As-contaminated water, 36–58 μg/l (3–50% and 12–61% for sunned and parboiled rice respectively) with increasing selenium (Se) concentration. Movement of As from water to rice grain has been inferred with increasing water As (84–105 μg/l), which results in a significant increase of As in cooked rice (24–337% and 114% for sunned and parboiled rice, respectively) with decreasing Se concentration. Arsenic speciation study emphasizes the fact of similar reduction percentage of As (III), As (V) and total As in wet cooked rice when cooked with low-As containing water. The SAMOE value in ‘risk thermometer’ supports the higher risk of suffering from wet cooked rice (class 4) with increasing cooking water As concentration (class 3 to class 5).

Antimicrobial peptide LL-37 and its pro-form, hCAP18, in desquamated epithelial cells of human whole saliva.

The antimicrobial peptide LL-37 is active against oral bacteria and has been demonstrated to be present in human saliva, but its distribution in different fractions of saliva is not known. LL-37 is formed from its intracellular pro-form, hCAP18, in an extracellular enzymatic reaction catalyzed by proteinase 3 and kallikrein 5. Here, we prepared cell-containing and cell-free fractions of unstimulated human whole saliva by centrifugation after depolymerization of mucins with dithiothreitol, and measured the levels of hCAP18/LL-37 in these fractions using ELISA. Cellular expression of hCAP18/LL-37 was determined by western blotting and immunocytochemistry. The ELISA analyses demonstrated that both cells and cell-free saliva contained hCAP18/LL-37. Western blot analysis of cell-pellet homogenates showed a strong band corresponding to hCAP18 at the correct molecular weight and a weak band corresponding to LL-37. Phase-contrast and light microscopy revealed that the cells consisted of desquamated epithelial cells. These cells expressed cytoplasmic immunoreactivity for hCAP18/LL-37. The peripheral part of the cytoplasm, corresponding to the plasma membrane, was particularly rich in hCAP18/LL-37 immunoreactivity. No immunoreactivity was observed after omission of the primary antibody. We conclude that desquamated epithelial cells of human whole saliva contain antimicrobial hCAP18/LL-37, suggesting that these cells may take part in the innate immune system by harboring and releasing these peptides.

Heavy metal accumulation in surface sediments of the Ganga River (India): speciation, fractionation, toxicity, and risk assessment.

We investigated the distribution of different fractions of eight heavy metals (Zn, Cr, Cu, Pb, Cd, Ni, Fe, and Mn) in the bed sediment of the Ganga River. The study was conducted during summer low flow (March to June 2017) considering a 285-km middle stretch of the Ganga River between the Allahabad upstream and the Varanasi downstream. To assess the metal levels from a toxicological perspective, we tested the relationships between metals and sediment microbial/extracellular enzyme activities. Most of the metals showed a large fraction in residual form. However, Zn, Pb, and Cd showed about 20-30% share in the exchangeable form. The total metal concentration poorly reflected the toxicity but the exchangeable fractions did show strong negative correlations (r = - 0.83 to - 0.63; p < 0.01) with microbial/enzyme activities. Also, the nutrients and organic carbon showed strong positive correlations (r = 0.62 to 0.89; p < 0.001) with microbial/enzyme activity. The phosphate showed a strong negative correlation (r = -0.82; p < 0.001) with alkaline phosphatase. The principal component analysis (PCA) and the indices such as contamination factor (CF), enrichment factor (EF), pollution load index (PLI), geoaccumulation index (Igeo), and risk assessment code (RAC) revealed moderate to severe contamination with strong anthropogenic influence. As per the United States Environmental Protection Agency, the metal concentrations at many locations were in the highly toxic range. The study has relevance from a toxicological perspective and for the management of the Ganga River.

Inorganic phosphorus fractions and crop productivity in response to different rates of phosphate-solubilising fungi Penicillium bilaii

Two field experiments were conducted at experimental farm of ICAR-Indian Agricultural Research Institute, New Delhi during 2014-15 to investigate the interactive effect of three rates of seed inoculation with wettable formulation of phosphate solubilising fungi (Penicillium bilaii) and two rates (60 kg and 30 kg P2O5/ha) of chemical phosphorus (P) fertilization on soil P availability and productivity in wheat (Triticum aestivum L.) and mustard (Brassica campestris L.) crops. Inorganic P distribution in different fractions was conducted by successive extraction of soil P with water, NaHCO3 (SB-P), NaOH (SH-P) and HCl. Application of fungal formulation @10.604 g/kg mustard seed and 4.894 g/kg wheat seed + 30 kg P2O5/ha as chemical P increased the SB-P fraction of mustard and wheat grown soil by 145.7% and 140.7%, respectively compared to their respective un-inoculated controls at maturity. HCl-P was the major fraction under wheat soil with average contribution of 46% and 64.8% of total extractable P at 60 and 120 d of crop growth whereas SH-P was the major fraction under mustard grown soil. Improved soil P availability due to fungal inoculation could explain the role of phosphate solubilising fungi in soil P mobilization. The crop productivity however, was highest with highest rate of chemical P and fungal based formulation.

Response of phosphorus pools in Mollisols to afforestation with Pinus radiata D. Don in the Argentinean Pampa

The introduction of fast-growing coniferous species generates major changes in the edaphic phosphorus (P) dynamics. In general, the literature shows decreases in the organic and total P (Po and Pt) and increases in labile inorganic fractions and contradictory results in the associated enzymatic activity. Therefore, the aim of this study was to quantify the impact produced by the introduction of Pinus radiata on different P pools and to evaluate the enzymatic activity of acid phosphatases with respect to adjacent soils supporting natural grassland vegetation. In the Ventania area, six mature P. radiata stands (Forest treatment: F) and six adjacent natural grassland areas (Grassland treatment: Gr) were selected. On the organic horizons of F and the mineral soil of both treatments (0–90 cm), different P fractions like Pt, Po, inorganic P (Pi), occluded P (Poc), extractable P (Pe), soluble reactive P (SRP) and the acid phosphatase activity (APA) were quantified. The results indicated that the pine afforestation generated a new P reserve constituted by the organic horizons rich in Pt (17.2 g m−2), with a high proportion of Po and high concentration of Pe and SRP. In the mineral soil, no differences were detected between treatments for Po, although there were significant increases in Pi and Poc and consequently Pt, under the pines up to a depth of 90 cm. Labile fractions such as Pe and SRP, showed the major alterations associated with the land-use change, with concentrations up to eight times greater for Pe (0–15 cm) and more than10 times greater for SRP (15–60 cm) in relation with the grassland base line. The APA was similar between both ecosystems, however by calculating the APA/OC ratio, a significant decrease in the enzymatic efficiency was detected under the coniferous vegetation. Overall, the results showed that the afforestation with pines on natural grasslands developed on Mollisols produced a significant alteration of the vertical distribution of different pools of P. The increments of different inorganic fractions of P found under the pines, both labile and non-labile, could not be linked to specific extraction zones within the one-meter radius sampled from the trunk. The changes observed in the vertical distribution of different fractions of P indicates a profound alteration in the cycling of this element in afforestation of P. radiata on Mollisols.

Depth-wise distribution of different forms of nitrogen in apple growing soils of Pulwama district of Kashmir Valley

Depth-wise distribution of different fractions of nitrogen in some selective sites (soil depths) of district Pulwama of Kashmir valley was studied. In all the soil profiles nitrogen fractions (forms) decreased with increase in depth except the fixed NH 4 -N which increased with decreased depth. Organic nitrogen showed high significant positive correlations with total nitrogen (r=0.987***), organic nitrogen decreased with depth while the fixed NH 4 -N increased and these two fraction were also showed highly significant correlation with each other (r=0.645***).

Effect of Integrated use of Bio-Compost and Nitrogen on Productivity and Soil Properties of Sugarcane Plant–Ratoon System in Calcareous Soil

A field experiment was conducted for three consecutive seasons on sugarcane plant–ratoon system during years 2008–2014 at crop research farm, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar to evaluate the integrated effect of bio-compost and nitrogen on productivity and soil properties in calcareous soil. The distribution of different fractions of soil nitrogen viz. exchangeable NH4 +–N, hydrolysable NH4 +–N, hexoseamine-N, amino acid-N, unidentified-N and status of total-N were determined. The significant increase in number of millable cane (NMC) and cane yield was recorded in the treatments receiving bio-compost in combination with fertilizer-N over control both in plant and ratoon crops. The highest number of NMC (90.7 × 103/ha), cane yield (74.14 t/ha) and sugar yield (7.72 t/ha) of plant was recorded in treatments receiving 50% N through bio-compost +50% N through inorganic fertilizer. The residual effect of treatment receiving 50% N through bio-compost and 50% N through inorganic fertilizer was also pronounced on NMC (83.90 × 103/ha), yield (69.70 t/ha) and sugar yield (7.42 t/ha). Further, application of 100, 125 and 150% N through bio-compost resulted in gradual decrease in yield of plant, but on the contrary, it increased by 6–7% in ratoon crop as compared to plant cane. The uptake of nutrients varied significantly. The highest sugar yield (plant and ratoon) was recorded in treatment receiving 50% N through bio-compost +50% N through inorganic fertilizer. Addition of bio-compost either alone or in combination with inorganic fertilizer-N significantly improved organic carbon and availability of nutrients (N, P, K and S) with reduction in bulk density of post-harvest soil over control. The highest organic carbon (6.2 g/kg) and N (281.6 kg/ha), P2O5 (26.3 kg/ha), K2O (129.5 kg/ha) and S (33.6 kg/ha) was recorded in treatment receiving 150% N through bio-compost. The bulk density varied from 1.33 to 1.42 g/cm3. The EC increased while pH decreased with increasing levels of bio-compost. The significant improvement in microbial population was also recorded in bio-compost treated plots. After third crop cycle of sugarcane cropping system, application of bio-compost either alone or in combination with fertilizer significantly increased all the forms of N-fraction over control. Among the various N-fractions, non-hydrolysable-N was the dominant N-fraction.

Arsenic in Coal: Modes of Occurrence, Distribution in Different Fractions, and Partitioning Behavior during Coal Separation—A Case Study

The content and modes of occurrence of arsenic and its distribution in Yunnan coal of China as well as its partitioning behavior during the coal separation process were investigated. The following laboratory equipment such as proximate analyzer, ultimate analyzer, sulfur analyzer, inductively coupled plasma mass spectrometer and the methods including sequential chemical extraction process, screening analysis, float-and-sink analysis, heavy liquid separation, and progressive release flotation were frequently used during the research process. The coal sample has a high sulfur content of 8.21%, and its arsenic content is 15.1 μg/g, which is within the range of the mild enrichment level. Content relationship among the various modes of occurrence in order is sulfide-associated form (47.38%) > organically bounded form (18.09%) > silicate-associated form (17.51%) > carbonate-associated form (12.04%) > ion-exchangeable form (3.84%) > water-soluble form (1.14%). The sulfide-associated form is the dominant mode of ...

Distribution of different fractions of Iron, Zinc, Chromium, lead and Nickel in Soils around Petrol filling stations in selected Areas of Delta State, Nigeria

The geochemical forms of some heavy metals in soils around selected petrol filling stations were studied in order to assess the mobility and bioavailability of the metals and hence their potential environmental risk. Water soluble fraction (F1) contained an average of 0.97% iron, 1.40% zinc, 2.37% chromium, 2.08% lead and 41.96% nickel with the abundance trend of Ni &gt; Cr &gt; Pb &gt; Zn &gt; Fe. Metal bound to exchangeable phase followed the same abundance trend with an average of 6.46% nickel, 5.48% chromium, 2.64% lead, 2.55% zinc and 0.62% iron. Lead was predominantly associated with carbonate fraction with an average of 52.32% followed by iron with an average of 15.41%. Other metal average levels in the carbonate fractions were 9.66% for nickel, 8.78% for chromium, and 8.73% for zinc giving the abundance trend of Pb &gt; Fe &gt; Ni &gt; Cr &gt; Zn. The most important metal in iron-manganese oxide phase was zinc with an average of 42.49%, followed by iron with an average of 32.82%. The averages of the other metals bound to this phase were 30.39%, 13.24% and 6.46% for chromium, lead and nickel respectively. The organic bound metals were in the abundance trend of Fe &gt; Zn &gt; Cr &gt; Pb &gt; Ni with average of 39.48% for iron, 30.87% for zinc, 23.03% for chromium, 8.54% for lead and 4.94% for nickel. Nickel with an average of 51.58% was predominantly associated with the residual fraction. The other metals bound to this phase in order of their importance to the fraction had the average of 22.75% for chromium, 13.96% for zinc, 12.24% for lead and 10.97% for iron. The mobility factor values of the metals were moderately high with the abundance trend of Pb &gt; Ni &gt; Cr &gt; Fe &gt; Zn. The generally low levels of the metals in the residual fraction coupled with the mobility factor trend suggest potential risk for the metals.Keywords: Soil pollution, speciation, petrol filling stations, heavy metals, Delta State

Effect of organic and inorganic sources on the distribution of different fractions of potassium in vertisol

A field experiment was conducted at Dryland Research Station,Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani during 2003-04 and 2004-05 in Vertisol with application of organics and inorganics sources of nutrients under different cropping system viz. , soybean-pigeonpea and sorghum-pigeonpea. After these two crop cycles, the added potassium was found to be converted to various potassium fractions. Among the different fractions, maximum potassium was found in the form of total potassium followed by lattice potassium, non-exchangeable K, exchangeable K, Water soluble K. The Water soluble K and exchangeable K in soil decreased with the age of crop due to their utilization by crop for its nutrition. The relationship as simple and multiple regressions between available K and different K fractions was interdependent to each other.

Residual effects of organic Zn fertilizers applied before the previous crop on Zn availability and Zn uptake by flax (Linum usitatissium)

AbstractThe objective of this study was to compare the residual effect of zinc (Zn) from three Zn chelates (Zn‐aminelignosulfonate, Zn‐AML; Zn‐polyhydroxyphenylcarboxylate, Zn‐PHP; and Zn‐ethylenediaminedisuccinate, Zn‐EDDS), applied at two rates (5 and 10 mg Zn [kg soil]–1, respectively) to a previous crop, for a flax crop (Linum usitatissimum L.). For the greenhouse experiment, two different soils were used: a weakly acidic soil, classified as Typic Haploxeralf (Soilacid), and a calcareous soil, classified as Typic Calcixerept (Soilcalc). Plant availability of soil Zn was evaluated using the DTPA‐triethanolamine (TEA), Mehlich 3, and low‐molecular‐weight organic acids (LMWOAs) methods. Easily leachable Zn was determined, and soil Zn status was characterized based on the Zn distribution in different fractions obtained by a sequential extraction. The Zn reserves after the previous crop were substantial and ranged from 2.85% to 5.61% of available Zn (Mehlich 3‐extractable) with respect to the applied Zn. Plant parameters such as dry‐matter yield, total Zn, and soluble Zn concentrations were measured, and Zn utilization by plants was calculated. In both soils, the highest concentrations of available Zn were associated with the application of Zn‐AML at a rate of 10 mg Zn kg–1. In Soilacid the largest quantity of easily leachable Zn was also observed with Zn‐AML fertilizer. Similarly, Zn‐AML resulted in the highest Zn concentration in flax seeds (229 mg Zn kg–1 and 72 mg Zn kg–1 for the highest rate of Zn application to Soilacid and Soilcalc, respectively). The results suggest that these Zn chelates resulted in a residual effect in soils with appropriate concentrations of the most labile fractions of Zn and available Zn, particularly when Zn‐AML was applied at the highest rate. This chelate was more effective in Soilacid than in Soilcalc. In the weakly acidic soil at the lowest Zn level it was associated with the highest percentage of Zn utilization by the flax plant and the most effective Zn transfer from soil to the plant.

Distribution of fractions of zinc and their contribution towards availability and plant uptake of zinc under long-term maize (Zea mays L.) - wheat (Triticum aestivum L.) cropping on an Inceptisol

Intensive farming with high yielding cultivars, application of high analysis NPK fertilisers, and reduced use of organic manures caused a decrease in the availability of zinc (Zn) in Indian soils. We collected soil and plant samples from an ongoing long-term experiment at Indian Agricultural Research Institute, New Delhi, to study the distribution of different fractions of Zn in an Inceptisol and their contribution towards the Zn availability in soil and Zn uptake in maize–wheat crop rotation. The treatments used for the study were NPK, NPK + FYM, NPK + Zn, and control (no fertiliser or manure). The DTPA-Zn concentration in soil was higher where Zn had been applied and declined with an increase in soil depth. The distribution of different fractions of Zn under various treatments and depths was inconsistent, and varied in a cropping year. The average concentration of total Zn (mg/kg) was 183, 183, 171, and 211 in 0–0.15, 0.15–0.30, 0.30–0.45, and 0.45–0.60 m depth, respectively. Residual Zn was the dominant portion of total Zn at all soil depths. Grain and stover yield of maize ranged from 1.10 to 2.43 t/ha and 1.22 to 2.46 t/ha, respectively, under different treatments, whereas, the yield of wheat grain varied from 2.25 to 4.69 t/ha and that of wheat straw from 2.56 to 5.20 t/ha. Highest uptake of Zn by both the crops occurred in Zn-treated plots. Zinc associated with easily reducible manganese, carbonate and iron and aluminum oxides contributed directly towards DTPA-extractable Zn. Sorbed Zn (SORB-Zn) and Zn associated with organic matter (OM-Zn) contributed significantly towards Zn uptake by the 2 crops.

Heavy metals in sewage sludge amended soils determined by sequential extractions as a function of incubation time of soils

The distribution of metals in different fractions of sewage sludge-soils prepared by adding two different sludges (W1 and W2) at two rates, 20 g kg − 1 (a) and 200 g kg − 1 (b), to two different soils (S1 and S2) was determined. The aim was to know the evolution of heavy metals in amended soils with the incubation time. The samples were incubated for 18 months at temperature of 25 ± 2 °C and humidity close to field capacity, and distribution of Cd, Cr, Cu, Ni, Pb and Zn in fractions exchangeable (F1), dilute acid-extractable or carbonate bound (F2), Fe–Mn oxide bound (F3), organically bound (F4), and residual fractions (F5) was periodically determined by a sequential extraction method. The evolution of the chemical properties (pH and organic matter (OM)) of the mixtures was also determined. A decrease in the OM content with time and a modification in its composition was observed in the mixtures with higher rate of sludge. Using a multifactor analysis of variance significant differences ( p < 0.05) between distribution fractions of each metal at two rates of sludges studied were observed when soils and sludges at each incubation time were jointly considered. Also, significant differences ( p < 0.05) between distribution fractions of each metal corresponding to different soils, type and rate of sludges and incubation time were observed. The distribution of metals in different fractions in the amended soils at time T0 indicated the most of the metals concentrated in the residual fraction with percentages ranging from 60–80% for Cu, Pb and Zn and > 80% for Cd, Cr and Ni. Changes of metal distribution were found at different incubation times studied. Increase of concentration for Cd, Pb and Zn in F1, F2, F3 and F4 fractions respect to the unamended soil was observed. Cr as Ni displayed the lowest changes of metal distribution over the incubation period, and Cu distribution was mainly observed in F3 fraction from T0 to T6. The mobility index (MI) determined by extractable metals in F1 + F2 was modified due to the change of metal distribution in different fractions. It was in the order Zn > Cd ≈ Cu ≈ Ni ≈ Cr > Pb at T0 time and at time T6 was in the order Cd > Pb > Ni > Cu ≈ Zn > Cr. The results obtained indicated that pollution by heavy metals in studied soils derived from the amendment with selected sewage sludges from urban or agricultural-food industry water treatment plants could be negligible while the increase of the soil OM content could be of major importance. However, these results would not permit the prediction of metal accumulation in soils when successive additions of sewage sludges to soils are carried out. This would involve particular studies of assessment and control of metal total content to prevent that phytotoxic level in soils could be reached.

Study on the effect of grain storage and processing on deltamethrin residues in post-harvest treated wheat with regard to baby-food safety requirements

The effects of storage intervals and of milling procedures on dissipation of deltamethrin residues in post-harvest treated wheat grain were studied with the aim to obtain scientific data on compliance of the processed products with the safety requirements concerning baby foods. The insecticide formulation was applied on stored wheat at a recommended rate of active ingredient of 0.5 mg kg−1 and at a higher rate of 4 mg kg−1, performing the highest protective effect. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Eight fractions—bran, semolina, three types of groats, and three types of flour—were collected after milling of grain and analysed for determination of pesticide residues. The residues were determined by gas chromatography characterized by the limit of determination of 0.005 mg kg−1, low enough for enforcement of the maximum residue level of 0.01 mg kg−1 established by the European Commission Directive for any pesticide in cereal-based foods. Deltamethrin applied post-harvest on wheat as grain protectant was distinguished by low rate of degradation on the grain under practical storage conditions. One hundred and eighty days after treatment at an application rate of 0.5 mg kg−1, the residues were between 0.03 and 0.2 mg kg−1 in the various types of flour. Two hundred and seventy days after treatment at a rate of 4 mg kg−1, the residues in the flour were in the range of 0.4–1.5 mg kg−1.

Effect of grain storage and processing on chlorpyrifos-methyl and pirimiphos-methyl residues in post-harvest-treated wheat with regard to baby food safety requirements

A study was undertaken to assess the effects of storage intervals and of milling procedures on the dissipation of chlorpyrifos-methyl and pirimiphos-methyl residues in post-harvest-treated wheat grain and to obtain scientific data on the compliance of the processed products with safety requirements concerning baby foods. The insecticide formulations were applied on stored wheat at recommended rates (20 ml t−1). The initial concentration levels in whole grain were determined in samples taken 1 h after treatment. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Samples of treated grain were milled in a fractionating laboratory mill and eight fractions — bran, semolina, three types of groats and three types of flour — were collected and analysed for pesticide residues. The residues were determined by an analytical method based on acetone extraction, graphitized carbon clean-up and GC-ECD, respectively, and GC-NPD determination of residues. The limits of determination of both pesticides were 0.005 mg kg−1, which is high enough for enforcement of the European Commission Directive that established a maximum residue level of 0.01 mg kg−1 for any pesticide in cereal-based baby food. The results showed that the pesticides chlorpyrifos-methyl and pirimiphos-methyl applied post-harvest on wheat as grain protectants were distinguished by relatively low rates of degradation in the grain under practical storage conditions. Milling did not significantly reduce the bulk of the chemicals but resulted in the distribution of residues in various processed products. The main part of the insecticides deposited on the grain remained in the bran and partly in semolina fractions. After 270 days of treatment, the residues of chlorpyrifos-methyl were within the range 0.8–2.1 mg kg−1 and of pirimiphos-methyl — between 0.6 and 3.7 mg kg−1 in the various types of flour.

Design and performance of the microdroplet filtering system used in cathodic arc coating deposition

The paper presents construction of a very simple and effective microdroplet filtering system. It describes the spatial angular distribution of different fractions of microdroplets generated by the cathode spots of the vacuum-arc evaporator equipped with the microdroplet filter and without it. The system was applied for TiN coating deposition. The influence of the filtering system on the TiN deposition process parameters is shown. Some properties of the TiN coatings (morphology, roughness, hardness and Young's modulus of elasticity, chemical composition and their adhesion to the steel substrate), deposited with the use of this filtering system, are pointed out.