Total Mn Research Articles

An Assessment of the Bivalve Perna viridis, as an Indicator of Heavy Metal Contamination in Paradise Point of Karachi, Pakistan

The edible bivalves Perna viridis (green mussel), (n = 100) were analysed for their total Hg,Pb, Cu, Ni, Zn, Co, Fe, Cr, Cd, and Mn concentrations to indicate heavy metal contamination in ParadisePoint of Karachi coast using atomic absorption spectrophotometer. There are large seasonal variations inthe metal concentrations of Mn (0.025-0.67 µg/g), Fe (0.055-7.740 µg/g), Ni (0.004-0.52 µg/g), Hg (0.0001-0.004 µg/g), Zn (0.04-3.32 µg/g), Cu (0.008-1.66 µg/g), Pb (0.022-2.43 µg/g), Co (0.01-0.044 µg/g), Cd(0.04-0.88 µg/g) and Cr (0.13-1.20 µg/g) recorded in bodies/soft tissues of P. viridis obtained in the samplesof the year 1993 and 2012 at the Paradise Point of Karachi coast. The results of heavy metals are in thefollowing descending order of concentration in the samples collected in the year 1993: Fe>Cr>Zn>Mn>Pb>Cd>Cu>Ni>Co>Hg, while Fe>Zn>Pb>Cu>Cr>Cd>Mn>Ni>Co>Hg order was recorded in samplescollected in the year 2012. The high accumulation of metals was found mostly in the samples collectedin the year 2012 when compared with the samples of the year 1993. This is an indication that the areaunder study showed signs of being exposed to significant levels of heavy metal pollution due to directdischarge of industrial and domestic wastes along the coast. The concentrations of these heavy metals werelower than the permissible limits for human consumption. However, if this pollution persists, it can proveto be very detrimental in future.

Distribution of heavy metals in maize and mudflat saline soil amended by sewage sludge

Sewage sludge has been considered as the economic choice for soil amendment. However, whether sewage sludge can effectively amend mudflat saline soil remains unclear. This paper was one of first studies to fill this knowledge gap by assessing the persistent effects of one-time application of sewage sludge on distribution of heavy metals in maize (Zea mays L.) grown in mudflat saline soil. On the premise of total amount of heavy metals from sewage sludge being in compliance with agricultural standard in China (GB/T 24600-2009), sewage sludge was used through one-time application, with the rates of 0, 30, 75, 150, and 300 t ha−1, to amend infertile mudflat soils. Ryegrass, Sesbania, and ryegrass were chosen as green manures for three consecutive seasons, successively planted and tilled. Maize was chosen as a test crop and sowed in 10th July 2013 and harvested 72 days after sowing. The results indicated that the sewage sludge amendment (SSA) increased uptake of cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) in maize tissues, whereas it did not inhibit maize growth, and dry matter of maize plant tissues increased with increasing SSA rates. Total Cd, Cu, Pb, and Zn concentrations in mudflat soil increased with increasing SSA rates, but there were no significant changes in total Mn and Ni concentration in response to SSA. The highest Cd, Cu, Mn, Ni, and Pb concentrations were observed in roots of maize, and the root system acted as a barrier for metals, so metal uptake and translocation were lower in aerial parts of maize plant. The labile fraction of Cd, Cu, Mn, Ni, Zn, and immobile fraction of Pb in the sludge-amended soils increased with increasing SSA rates. The metal levels in grains were negligible in all the treatments and below the maximum permitted concentrations as specified in the national control standard in China (GB2715-2005). Sewage sludge can be applied with green manure for mudflat saline soil amendment, which provides an innovative solution for arable land resources and solid waste disposal.

Hydrous Ferric Oxides in Sediment Catalyze Formation of Reactive Oxygen Species during Sulfide Oxidation

Abstract: This article describes the formation of reactive oxygen species as a result of the oxidation of dissolved sulfide by Fe(III)-containing sediments suspended in oxygenated seawater over the pH range 7.00 and 8.25. Sediment samples were obtained from across the coastal littoral zone in South Carolina, US, at locations from the beach edge to the forested edge of a Spartina dominated estuarine salt marsh and suspended in aerated seawater. Reactive oxygen species (superoxide and hydrogen peroxide) production was initiated in sediment suspensions by the addition of sodium bisulfide. The subsequent loss of HS-, formation of Fe(II) (as indicated by Ferrozine), and superoxide and hydrogen peroxide were monitored over time. The concentration of superoxide rose from the baseline and then persisted at an apparent steady state concentration of approximately 500 nanomolar at pH 8.25 and 200 nanomolar at pH 7.00 respectively until >97% hydrogen sulfide was consumed. Measured superoxide was used to predict hydrogen peroxide yield based on superoxide dismutation. Dismutation alone quantitatively predicted hydrogen peroxide formation at pH 8.25 but over predicted hydrogen peroxide formation at pH 7 by a factor of approximately 102. Experiments conducted with episodic spikes of added hydrogen peroxide indicated rapid hydrogen peroxide consumption could account for its apparent low instantaneous yield, presumably the result of its reaction with Fe(II) species, polysulfides or bisulfite. All sediment samples were characterized for total Fe, Cu, Mn, Ni, Co and hydrous ferric oxide by acid extraction followed by mass spectrometric or spectroscopic characterization. Sediments with the highest loadings of hydrous ferric oxide were the only sediments that produced significant dissolved Fe(II) species or ROS as a result of sulfide exposure.

Assessment of the selected trace metals in relation to long-term agricultural practices and landscape properties

Understanding of the landscape response to agricultural practices mainly in relation to soil trace metals requires particular attention. Consistent with this, the trend and possible pollution of total and DTPA fraction of Mn, Zn, Cu, and Cd in the agricultural soils developed on different landscape positions involving piedmont alluvial plain (PAP), river alluvial plain (RAP), plateau (PL), and lowland (LL) were investigated. The content of the metal in different soil profiles, grouped by landscape positions, varied in the following orders: total and DTPA-Mn as LL > PAP > RAP > PL, total Zn and Cu as PAP > RAP > LL > PL, total Cd as RAP > PAP > PL > LL, DTPA-Zn as RAP > PAP > PL > LL, and DTPA-Cu as RAP > LL > PL > PAP. A wide variation in the total fraction of Mn (89–985 mg kg−1), Zn (24–152 mg kg−1), Cu (8–27 mg kg−1), and Cd (0.6–1.7 mg kg−1) and in the DTPA fraction of Mn (1.2–11 mg kg−1), Zn (0.3–4.4 mg kg−1), Cu (0.3–3 mg kg−1), Cd (0.03–0.09 mg kg−1) observed as a result of the effects of agricultural practices and landscape properties. The values of both total and DTPA-extractable Mn, Zn, and Cu were enriched in the AP horizon probably due to anthropogenic activities particularly successive use of agrochemical compounds and manure during numerous years. Using soil pollution indices [single pollution (PI) and comprehensive pollution (PIN)], the study soils were categorized mainly as low to moderate pollution and Zn was identified as the major element affecting on the yield of these indices.

Physical characteristics and proximate and mineral composition of Saanen goat male kids meat from Vojvodina (Northern Serbia) as influenced by muscle

The aim of this study was to investigate the influence of the anatomical location of muscles on their physical characteristics and proximate and mineral composition. Physical (pH value, water-holding capacity − WHC, and instrumental colour − CIEL*a*b* values) characteristics and proximate (moisture, protein, total fat and total ash) and mineral (K, P, Na, Mg, Ca, Zn, Fe, Cu, Ni and Mn) composition were determined in four (M. psoas major − PM, M. longissimus dorsi − LD, M. semimembranosus − SM, and M. triceps brachii − TB) muscles of Saanen goat male kids. Many significant or numerical differences were found in the mean values of quality characteristics among the particular muscle types. Muscles had no significant influence (P>0.05) on Mg, Ca, Ni and Mn content. The PM muscles were the highest in pH24h (5.83), CIEa* (22.47, reddest muscle), CIEb* (5.90) values, moisture (77.61g/100g), Na (78.2mg/100g), Fe (1.57mg/100g), Cu (0.131mg/100g) and Mn (0.013mg/100g) content and had the highest WHC, darkest colour (CIEL*=38.03), and lowest content of total fat (1.40g/100g),K (330mg/100g) and Ni (0,019mg/100g). The LD muscles were the highest in K (392mg/100g), Mg (26.1mg/100g), Ca (11.8mg/100g) and Ni (0.030mg/100g) content, and the lowest in CIEa* (14.71) and CIEb* (3.84) values, total ash (1.15g/100g), Zn (2.24mg/100g), Cu (0.092mg/100g) and Mn (0.011mg/100g) content. The highest content of protein (20.69g/100g), total ash (1.20g/100g) and P (255mg/100g), and the lowest pH24h (5.68) value, WHC and moisture (76.42g/100g), Na (64.2mg/100g), Fe (1.07mg/100g) and Mn (0.011mg/100g) content were found in SM muscles. The lightest colour (CIEL*=44.02), the highest content of total fat (2.15g/100g), Zn (3.21mg/100g) and Mn (0.013mg/100g), and the lowest content of protein (19.29g/100g), total ash (1.15g/100g), P (223mg/100g), Mg (24.3mg/100g) and Ca (10.6mg/100g) were found in TB muscles. Significant relationships between quality characteristics of meat in number of cases were determined. This study was undertaken to increase the available information on the physicochemical traits of goat meat. This is important to provide, update and improve regularly nutrient composition data of goat meat.

“Uncontrolled” Preparation of Disperse Poly(lactide)-block-poly(styrene)-block-poly(lactide) for Nanopatterning Applications

We report the facile synthesis of well-defined ABA poly(lactide)-block-poly(styrene)-block-poly(lactide) (LSL) triblock copolymers having a disperse poly(styrene) midblock (Đ = 1.27–2.24). The direct synthesis of telechelic α,ω-hydroxypoly(styrene) (HO-PS-OH) midblocks was achieved using a commercially available difunctional free radical diazo initiator 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]. Poly(lactide) (PLA) end blocks were subsequently grown from HO-PS-OH macroinitiators via ring-opening transesterification polymerization of (±)-lactide using the most common and prevalent catalyst system available, tin(II) 2-ethylhexanoate. Fourteen LSL triblock copolymers with total molar masses Mn,total = 24–181 kg/mol and PLA volume fractions fPLA = 0.15–0.68 were synthesized and thoroughly characterized. The self-assembly of symmetric triblocks was analyzed in the bulk using small-angle X-ray scattering and in thin films using grazing incidence small-angle X-ray scattering and atomic force microscop...

THE TOTAL AND AVAILABLE CONCENTRATIONS OF ESSENTIAL TRACE ELEMENTS IN AGRICULTURAL SOILS OF EASTERN CROATIA

UDK 631.41:546.4(497.6)
 The research objective was to determine the influence of basic soil chemical properties on total concentration and available fractions of essential trace elements in the soil. Agrochemical soil analysis were conducted at two localities of different soil properties Berak and Vinogradci in eastern Croatia. The soil at the site Berak was eutric cambisol of neutral reaction (pH average (H2O) 7.20), while the soil in Vinogradci was luvisol of slightly acid reaction (average pH (H2O) 5.87). Both soils were poor in organic matter and well supplied with phosphorus and potassium. As expected, at both analyzed sites the highest average concentrations were determined for total Fe, Mn and Zn followed, and the lowest concentrations were for total Cu. Higher total concentrations of analyzed microelements were recorded at the Berak site. The total concentrations of Zn and Cu in all analyzed soil samples were below the maximum permissible concentrations. The highest average concentration of available microelements fraction by EDTA Extraction, were at the Berak site determined for Mn (50.52 mg/kg), then Fe (21.77 mg/kg), Cu (4.78 mg/kg), and the lowest for Zn (1.47 mg/kg). At the Vinogradci site average concentrations of available fraction of microelements determined by EDTA extraction were the highest for Fe (77.09 mg/kg), then Mn (30.75 mg/kg), Cu (4.36 mg/kg), and the lowest for Zn (1.76 mg/kg). Identical order of average concentrations at both sites was also recorded for extraction with DTPA solution. Comparing available fraction of microelements by localities, higher average concentrations of Mn and Cu were found at the site Berak, while on site Vinogradci higher average concentrations were of Fe and Zn. At both sites the DTPA method extracted more of Fe and Mn, an average of 51.06% and 6.39% more than the EDTA method, but the method EDTA extracted more Zn and Cu, an average of 127.10% and 100.40% than DTPA method. The smallest share of the available fraction of the total concentration was recorded for Fe (0.06% by EDTA -0.09% by DTPA ), followed by Zn (1.20% by DTPA - 2.74% by EDTA) and Mn (5.93% by EDTA – 6.31% by DTPA), while the largest share was observed for Cu (10.92% by DTPA and 21.84% by EDTA).

English

The use of organic solid waste/effluent has currently been increasingly enhanced. A waste and effluent currently produced on a large scale that have potential for use in agriculture refers to sludge tannery and wastewater, respectively. However, in Brazil these residues are still little used and there is great reluctance to use them in general agriculture. Thus, this study aimed to evaluate the characteristics of an Oxisol after maize cultivation (Zea mays L.) using tannery sludge vermicompost and irrigation with wastewater. After 120 days of cultivation, soil samples were collected for analysis of the: pH, electrical conductivity (EC), total organic carbon (TOC), base saturation (BS), organic matter (OM), N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn. The values for these parameters were compared between the various treatments, as well as the values observed in the soil prior to cultivation. It was observed that the tannery sludge vermicompost and irrigation with wastewater, provided little increase in pH, EC, TOC, base saturation, OM, N, P, K, Cu and Fe compared to their concentrations originally identified in the soil. Moreover, tannery sludge vermicomposts and wastewater constitute good sources of Ca, P, Mg, Mn and Zn, being able to increase the content of these elements in the soil. Key words: Agro-industrial waste, tannery, Zea mays L., Oxisol.

Effects of dietary manganese supplementation on nutrient digestibility and production performance in male sika deer (Cervus Nippon).

This study aimed to investigate the effects of manganese (Mn) supplementation on nutrient digestibility and antler growth in male sika deer. Twenty 3-year-old male sika deer were divided into four groups (Control, T40, T80 and T120). The control diet contained 22.2 mg Mn/kg. The treatment diets were supplemented with 40, 80 and 120 mg of Mn/kg (provided as Mn methionine). The results showed that the digestibility of dry matter and crude protein in the T80 group was greater than other groups. Higher digestibility of neutral detergent fiber and acid detergent fiber was observed in the T80 group than in the control group. Plasma Mn concentrations in the T80 and T120 groups were higher (P < 0.01) than control and T40 group (P < 0.01). The concentration of Mn in feces was increased with increasing Mn amount. Average daily gain of fresh antler and dry antler of T80 was greater than other groups, especially the control group (P < 0.05). In conclusion, the suitable level of Mn supplementation was found to be 80 mg/kg (total Mn content 103.4 mg/kg dry matter), which significantly increased antler daily gain and feed digestibility in 3-year-old sika deer.

Heavy metal pollution load in sediment samples of the Buriganga river in Bangladesh

A study was conducted to assess the level of Cr, Pb, Cd, Ni, Zn, Cu, Fe and Mn contamination in the sediment samples of the Buriganga river, at the Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh. Total 14 sediment samples were collected from different areas of upstream of the Buriganga river. The mean concentrations of total Cr, Pb, Cd, Ni, Fe, Cu, Zn and Mn in the sediment samples were 173.4, 31.4, 1.5, 153.3, 481.8, 344.2, 12989 and 4036 ?g g-1, respectively. The range of pH and EC of sediment were 5.87-8.21 and 230-707 ?S cm-1, respectively. The mean value of organic matter in sediment samples was 13.4%. Heavy metal concentrations in sediment were compared with geochemical background and standard values, previous report on the Buriganga river and other rivers in Bangladesh. The average concentration of Cr, Pb and Ni in sediments of the Buriganga river is almost twice of the geochemical background i.e. average worldwide shale standard and continental upper crust value, Cd and Zn is about five times and Cu content is about ten times higher than the geochemical background values. Average concentration of Cr, Cu and Ni exceeded the severe effect level (SEL) values, where as Pb, Cd and Zn exceeded toxicity reference values (TRV). However, the concentration of heavy metal in the sediment samples of the Buriganga river for the year 2009 of the same river reported by corresponding author was relatively higher than this study average. The average Enrichment factors (EFc) for Zn, Cu, Mn and Cd reflects extremely contaminated pollution level which implies that these metals originated from point source of pollution and very severely enriched in river sediments. The pollution load index (PLI) of sediments of the studied region varied from 1.61-7.51. The geoaccumulation index (Igeo) for Cu of five locations was greater than 3.0, which exhibited strongly polluted sediment quality. The Igeo for Mn in 11 locations and Zn in 12 sites were greater than 1.0, indicated moderately polluted sediment quality. Heavy metal pollution intensity in the Buriganga river water and sediments signaled alarming condition for city dwellers and aquatic ecosystem of the river. Sustainable steps and continuous monitoring on pollution prevention and cleanup operation is suggested to minimize pollution.J. Bangladesh Agril. Univ. 13(2): 229-238, December 2015

Synthesis of manganese incorporated hierarchical mesoporous silica nanosphere with fibrous morphology by facile one-pot approach for efficient catalytic ozonation

Manganese incorporated fibrous silica nanosphere (MnOx-0.013/KCC-1) was synthesized by one step hydrothermal method for the first time and its catalytic activity for ozonation of oxalic acid was studied. For comparison, manganese loaded MCM-41 (MnOx-0.013/MCM-41) was prepared by impregnation method. Various characterizations showed that the morphological, structural and textural properties of MnOx-0.013/KCC-1 were well preserved. Ozonation and catalytic ozonation by MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41 led to 4, 85 and 60% reduction in TOC respectively. Furthermore, 0.05 and 1.2mgL−1 leaching of Mn was detected from MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41, which are approximately 2.0 and 42.0% of the total Mn present in MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41 respectively. The high catalytic activity was attributed to the generation of hydroxyl radical. Surface hydroxyl groups investigated by using phosphates and ATR-FTIR were believed to be the active sites. Our proposed method of synthesis can be generalized for the synthesis of other metal oxides incorporated fibrous silica for environmental catalysis and other catalytic reactions.

Manganese status in upland and lowland rubber-growing soils in Songkhla province, southern Thailand

Rubber trees, the most economic crop in southern Thailand, are generally cultivated in acid upland soils and currently have been extended into lowland areas which induce higher solubility of manganese (Mn) which may result in Mn toxicity to rubber. This study investigated soil Mn and leaf Mn levels in rubber trees grown in upland and lowland soils. Ninety soil samples from upland and lowland rubber plantations in Songkhla province were collected and analyzed for water soluble Mn, NH4OAc Mn, diethylenetriaminepentaacetic acid test (DTPA) Mn, reducible Mn and total Mn forms. Leaf Mn analysis was also undertaken on samples of each plantation. The results revealed that the Mn concentrations of all soil Mn forms and leaf Mn in the lowland soils were higher than those of the upland samples. Comparing the optimum level reported by the Rubber Research Institute, both DTPA Mn and leaf Mn in the upland and lowland samples were high. Correlation analysis showed high and significant positive correlations of DTPA Mn and water Mn (r = 0.715), NH4OAc Mn (r = 0.975), reducible Mn (r = 0.953) and total Mn (r = 0.809) in the lowland samples. Medium to high positive correlations among Mn forms were also found in the upland samples. The correlation of soil properties (pH, electrical conductivity, organic matter, available K, exchangeable Ca, Mg and Na and cation exchange capacity) and soil Mn were clearly defined. These results indicated that soil properties affect the release of Mn. However, a correlation between soil Mn and leaf Mn was not observed.

Water Quality and Sediment Profile in Shrimp Culture with Different Sediment Redox Potential and Stocking Densities Under Laboratory Condition

Sediment quality has been considered as one of the prime factors influencing the environment quality that support maximum shrimp production.The aim of the study was toevaluate the effects of sediment redox potential and shrimp stocking density on the profile of some sediment and water quality parameters. Two factors randomized factorial design was applied, with stocking density (60 and 120 shrimps.m-2) as the first variable and sediment redox potential (-65 mV, -108 mV and -206 mV) as the second variable. Some significant changes in TP, total Mn, and total S concentrations in the sediment were observed after the experimentation (P&lt;0.05). Sediment redox potential significantly affected the dissolved oxygen, TAN, NO2, NO3, and H2S concentrations in the water. Whereas shrimp stocking density affected all water quality parameters except H2S concentration. Significant interactions between redox potential and stocking densities were observed in the nitrite and alkalinity concentrations. The significant effects of both shrimp density and redox potential on the sediment and water parameters in particular those that are known to directly affect the shrimp welfare (e.g. oxygen, ammonia, nitrite and H2S) indicate that these variables are of important aspects in shrimp pond management. Furthermore, the results clearly showed that -206mV redox potential significantly reduced the dissolved oxygen concentration in the sediment-water interface and increased the generation of H2S in water column. Thereby, this redox potential level is not advisable for shrimp culture system. Keywords: redox potential, stocking density.

Sediment pollution characteristics and in situ control in a deep drinking water reservoir

Sediment pollution characteristics, in situ sediment release potential, and in situ inhibition of sediment release were investigated in a drinking water reservoir. Results showed that organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) in sediments increased from the reservoir mouth to the main reservoir. Fraction analysis indicated that nitrogen in ion exchangeable form and NaOH-extractable P (Fe/Al-P) accounted for 43% and 26% of TN and TP in sediments of the main reservoir. The Risk Assessment Code for metal elements showed that Fe and Mn posed high to very high risk. The results of the in situ reactor experiment in the main reservoir showed the same trends as those observed in the natural state of the reservoir in 2011 and 2012; the maximum concentrations of total OC, TN, TP, Fe, and Mn reached 4.42mg/L, 3.33mg/L, 0.22mg/L, 2.56mg/L, and 0.61mg/L, respectively. An in situ sediment release inhibition technology, the water-lifting aerator, was utilized in the reservoir. The results of operating the water-lifting aerator indicated that sediment release was successfully inhibited and that OC, TN, TP, Fe, and Mn in surface sediment could be reduced by 13.25%, 15.23%, 14.10%, 5.32%, and 3.94%, respectively.

Dietary manganese source does not affect Mn, Zn and Cu tissue deposition and the activity of manganese-containing enzymes in lambs

Manganese (Mn) is a trace element required for normal physiological processes in animals and humans. Organic forms of trace elements are expected to have higher bioavailability in comparison with inorganic sources. The effect of feeding a diet supplemented with different sources of manganese to lambs was studied in a 112-d feeding trial. The aim of this study was to investigate the deposition of Mn in relation to activities of superoxide dismutase (SOD), manganese superoxide dismutase (MnSOD) and arginase in the tissues of lambs fed the diet supplemented with an inorganic or an organic source of manganese up to the maximum total Mn content allowed in the European Union (150mg Mn/kg). A total of eighteen female lambs of the improved Valachian breed were randomly allocated to three dietary treatments and fed an unsupplemented basal diet (Control, 31mg Mn/kg) or the identical diet supplemented with manganese sulphate (MnSO4) or manganese chelate of glycine hydrate (Mn-Gly) with a total Mn content up to 150mg/kg. Regardless of the source, feed supplementation with manganese increased Mn concentrations in plasma (P˂0.05) and the liver (P˂0.001) as well as the activity of liver MnSOD (P˂0.05) and arginase (P˂0.001) compared with the control lambs. In the kidney cortex, the concentration of Mn was greatest in lambs fed the diet supplemented with the chelated Mn source compared with animals receiving the inorganic Mn source (P˂0.05) and the unsupplemented diet (P˂0.001). The 112-d intake of feed enriched with manganese did not result in any change in Mn levels, SOD or MnSOD activity in pancreas and kidney tissues. Plasma Cu concentration was depressed in both supplemented treatments. No analyzed tissue showed a change in zinc and copper levels, except the greater Cu concentration in the liver of lambs fed the diet with Mn-Gly. The presented results did not indicate any differences between dietary Mn sources either in Mn tissue deposition or activity of SOD, MnSOD and arginase in lamb tissues; however, it seems that manganese intake of up to 150mg/kg in feed may decrease plasma Cu concentration in lambs.

Bioaccessibility and arsenic speciation in carrots, beets and quinoa from a contaminated area of Chile

Consumption of vegetables grown in arsenic (As)-contaminated soils is an important exposure route to the element for humans. The present study is focused on locally-grown, frequently-consumed vegetables, such as carrots (Daucus carota), beets (Beta vulgaris) and quinoa (Chenopodium) from the As-polluted Chiu Chiu area in Northern Chile. The latter region is affected both by As discharge from copper mining activity and natural As contamination, leading to a high As content in local food and water. For the selected vegetables, the following aspects were investigated: i) Their total As, Cu, Pb, Cr, Cd and Mn content; ii) Arsenic speciation in the edible part of the vegetables by liquid chromatography inductively-coupled plasma mass spectrometry (LC-ICPMS) analysis; iii) Arsenic bioaccessibility in the vegetables during in vitro gastrointestinal digestion; iv) Arsenic species present in the extracts obtained from in vitro gastrointestinal digestion; and v) Arsenic dietary exposure estimates for the assessment of the risk posed by the vegetables consumption.A significant degree of As contamination was found in the vegetables under study, their metal content having been compared with that of similar Spanish uncontaminated products. In vitro gastrointestinal digestion of the studied vegetables led to quantitative extraction of As from carrots and beets, whereas efficiency was about 40% for quinoa. For carrots, only As(III) and As(V) species were found, being their concentration levels similar. In the case of quinoa, around 85% of the element was present as As(V). For beets, inorganic As(V) and unknown overlapped As species (probably arsenosugars) were found. No significant transformation of the original As species was observed during in vitro gastrointestinal digestion. Arsenic dietary exposure values obtained for the three vegetables (0.017–0.021μg As person−1day−1) were much lower than the JFCFA's safety limit of 50μg As person−1day−1. Therefore, no toxicological risk would be expected from the intake of these vegetables.

Effect of Mineral and Humic Substances on Tailing Soil Properties and Nutrient Uptake by Pennisetum purpureum Schumach

Tin mining produces a by-product sand tailing from soil leaching with characteristic low pH and total organic carbon, and can be reclaimed by providing a suitable ameliorant. When available in situ, ameliorant materials can be economically used as they are required in large amounts. Fortunately, Bangka Belitung has sample stock of such kaolinite-rich minerals that can be utilized for improving soil chemical properties. Extracted organic materials, such as humic substances, can also be utilized as they influence the complex soil reactions, and promote plant growth. Thus, this study aimed to assess the effects of mineral, humic materials and interaction of both material on soil chemical properties and nutrient uptake of Pennisetum purpureum Schumach. A completely randomized design with 2 factors and 3 replications each was employed. Factor 1 was mineral matter is 0; 420; 840; 1.260 Mg ha-1 while Factor 2 was humic material is 0; 0.46; 0.92; 1.38 kg C ha-1. Air-dried samples of tailing were applied with oil palm compost then mixed evenly with mineral and humic materials. Penissetum purpureum Schumach was planted after 4 weeks incubation, and maintained for another 4 weeks. The results demonstrated that the addition of mineral matter significantly increased soil organic carbon content, total N, exchangeable K, Fe, Mn and boosted nutrient - total Ca, Mg and Mn – uptake of the plant. But the application of humic material increased only soil organic carbon content. The interaction of both materials only lowered soil pH.

Cd Content in Sugarcane and Its Relationship with Soil Factors

Cadmium (Cd) safety in soil and crop in Huanjiang River is the focus of local society. In this study, we investigated the Cd concentration in stalk and leaf of sugarcane and its relationship with pH, organic matter, total Cd, available Cd and other cation content in soils in the sugarcane-producing region using correlation, regression and path analysis. The results showed that the Cd concentration in stalk and leaf of sugarcane was 0.245 and 1.031 mg kg−1, respectively, which was higher in leaf than in stalk. A total of 27.7 % of the sugarcane stalk samples had the Cd concentration of pollution level, according to the Chinese food safety standards (0.2 mg kg−1). Simple correlation showed that available Cd concentration in soil was significantly correlated with total Cd, available Cu, Zn and Mn, but not with pH, organic matter, available Ca, Mg and Fe in soil. The Cd concentration in stalk and leaf of sugarcane was mainly influenced by total Cd, available Cd, Cu, Zn and Mn in soil. Multiple regression and path analysis further showed available Cd was the main influencing factor, followed by available Zn. Therefore, it would be effective to control the Cd concentration in sugarcane by controlling Cd input and regulating the available Cd and Cd–Zn relationship in soil.

Redox processes and occurrence of arsenic in a volcanic aquifer system of Kumamoto Area, Japan

Sources, distributions, and controlling factors for mobilization of arsenic (As) in Kumamoto basin were investigated relating to the determination of redox processes of the study area. Groundwater and sediment core samples were analyzed. Nitric acid digestion and sequential leaching experiment of sediment core samples revealed that the source of As in the groundwater is geogenic and leached primarily due to the sediment–water interactions. Unlikely, similar relations of total As with total Fe, Mn, and Al in acid extracts, leaching experiments showed a positive relation of Astotal with Fetotal and Altotal indicated that Fe and Al oxides/hydroxides are abundant and may be the major adsorbent of As in low pH condition. Arsenic concentrations in groundwater ranges from 0.1 to 60.6 μg/l. High As concentrations occurred in anaerobic stagnant groundwaters from Kumamoto plain area with high dissolved Fetotal, Mntotal, and Altotal, moderately dissolved HCO3 −, PO4 3−, SO4 2−, and low concentrations of NO3 − and DOC suggesting the reducing condition of subsurface aquifer. There is a range of As(III)/As(T) ratios from mostly arsenate to mostly arsenite. Groundwater pH was relatively high, and high As occurred at higher pH range. It is assumed that desorption of As from metal oxide surfaces was facilitated by the elevated pH, which is considered as an important process for As mobilization. In addition to this, a wide range of δ34SSO4 values (8.3–57.6 ‰) indicates that sulfur is undergoing redox cycling mediated by microbial activities. Following δ34SSO4 results, it is anticipated that dissolved As is coprecipitated as sulfides in the presence of dissolved Fe(II) in some places, though at this moment, there is no direct evidence of coprecipitation or sequester of As with Fe and sulfide ion. Finally, a combination of the following three variables are considered potentially important causes for the high dissolved As concentrations in groundwater of Kumamoto area—(1) high groundwater pH, (2) anoxic redox conditions, and (3) stagnant groundwater in younger age sediments, which have not been well flushed since burial.

Parking functions for mappings

We apply the concept of parking functions to functional digraphs of mappings by considering the nodes as parking spaces and the directed edges as one-way streets: Each driver has a preferred parking space and starting with this node he follows the edges in the graph until he either finds a free parking space or all reachable parking spaces are occupied. If all drivers are successful we speak of a parking function for the mapping. We transfer well-known characterizations of parking functions to mappings. Via analytic combinatorics techniques we study the total number Mn,m of mapping parking functions, i.e., the number of pairs (f,s) with f:[n]→[n] an n-mapping and s∈[n]m a parking function for f with m drivers, yielding exact and asymptotic results. Moreover, we describe the phase change behaviour appearing at m=n/2 for Mn,m and relate it to previously studied combinatorial contexts.