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1.
Appropriate compost standards are being considered in Canada. Five aspects of compost safety and quality are being evaluated; probably the most controversial aspect is the standards for metals in compost. In order to assist in the development of appropriate standards, the authors began an extensive research project in October, 1993 to determine the bioavailability of metals from compost and compost-metal mixtures. Swiss chard was grown in compost-amended soils or compost in a growth room using five treatments of increasing percentages of compost in the media (0, 25 percent, 50 percent, 75 percent, 100 percent compost (v/v)). A Truro loamy sand and a race-track manure-biosolids compost (RTM-biosolids) supplemented with a high metal biosolids were used in a completely randomized design with five replicates. Dry matter yield, metal content in plant tissue, and total metal uptake were evaluated as well as the total and DTPA-extractable metal content in the compost-soil mixes. The results of this and five other experiments conducted by the authors will help determine whether the suggested limits for As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se and Zn in composts are appropriate.  相似文献   

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Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana 1, P. taeda 3, P. strobus 4, P. resinosa 4, P. sylvestris 5, and P. radiata 6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.  相似文献   

4.
A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4--5 micrograms/kg; ochratoxin A or ethyl ester A 140--145 micrograms/kg; citrinin 600--750 micrograms/kg; zearalenone, 410--500 micrograms/kg; sterigmatocystin, 140--145 micrograms/kg; diacetoxyscirpenol, 2400--2600 micrograms/kg; T-2 toxin, 800--950 micrograms/kg; patulin, 750--800 micrograms/kg; penitrem A 14,000--14,500 micrograms/kg; penicillic acid 3400--3650 micrograms/kg.  相似文献   

5.
A total of 244 samples of cereals (wheat flour, rice, and maize), pulses (arhar, moong, gram, lentil, and black gram), spices (turmeric, chili, coriander, and black pepper), vegetables (potato, onion, spinach, cabbage, brinjal, and tomato), fruits (mango, guava, apple, and grape), milk, butter, Deshi ghee, and edible oils (vegetable, mustard, groundnut, and sesame) collected from different cities of Northern Province (Utter Pradesh) were analyzed by gas liquid chromatography for the presence of organochlorine pesticide residues. Residues of hexachlorocyclohexane (HCH) and 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) were detected in about 85% of the total samples of cereals, spices, milk, butter, Deshi ghee, and edible oils analyzed in the present study. However, the residue levels were either very small (less than 0.06 ppm) or not detected at all in pulses, vegetables, and fruits as compared with very high concentrations in wheat flour (4.42 and 0.12 ppm), butter (1.19 and 4.85 ppm), mustard oil (1.26 and 2.42 ppm), Deshi ghee (1.10 and 3.84 ppm), vegetable oil (1.02 and 0.59 ppm), groundnut oil (0.51 and 1.49 ppm), and chili (0.48 and 1.92 ppm). The levels of HCH and DDT residues detected in rice, maize, turmeric, corlander, black pepper, and all the vegetables and fruits were also lower than those found in wheat flour, oil, and fat samples analyzed in the present study. These findings suggest that a restricted and controlled use of such persistent pesticides may be useful for decreasing their contamination levels in different food items.  相似文献   

6.
Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10‐5 M) and 142 (with 10‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10‐4 M AgNO3; at 10‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10‐5 N Cr2O7 were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr2(SO4)3 was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.  相似文献   

7.
Amazonia, the world's largest tropical rain forest, is often assumed to be a virtually untouched wilderness. The region is often referred to as a demographic void; there is on average only about one person per sq. km. Yet in response to international market forces, the hand of man has penetrated deep into the imposing forests. Since colonial times, wildlife, particularly along rivers, has been exploited on a large-scale basis for commercial purposes. This paper focuses on the effects of the trade on some aquatic animals.  相似文献   

8.
The total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin E, and tert-butylhydroquinone, were determined. Grape seed and green tea were analyzed for their phenolic constituents using high-performance liquid chromatography. The total phenolics of the plant extracts, determined by the Folin-Ciocalteu method, ranged from 24.8 to 92.5 mg of chlorogenic acid equivalent/g dry material. The antioxidant activities of methanolic extracts determined by conjugated diene measurement of methyl linoleate were 3.4-86.3%. The antioxidant activity of the extracts using chicken fat by an oxidative stability instrument (4.6-10.2 h of induction time) followed a similar trend in antioxidant activity as determined by the Folin-Ciocalteu method. Seven phenolics in grape seed and green tea extracts were identified that ranged from 15.38 to 1158.49 and 18.3 to 1087.02 mg/100 g of extract, respectively. Plant extracts such as green tea and grape seed extracts can be used to retard lipid oxidation in a variety of food products.  相似文献   

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Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log10. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.  相似文献   

11.
The losses of total solids, moisture, nitrogen (N), phosphorus (P), potassium (K), carbon (C), and sulfur (S) were determined in two storage events of laying-hen manure immediately removed from three different housing systems in Iowa, USA. The three laying-hen houses were conventional cage (CC), enriched colony (EC), and aviary (AV). The houses held a nominal number of 200,000, 46,700, and 50,000 Lohmann LSL lite layers, respectively. The manure collected on belts in each house was cleaned out twice a week. A fraction of the cleaned out manure was transferred to designated storage rooms wherein losses of different components were determined in two storage events. Manure was loaded into the storage rooms over 171 days during the first storage event and over 185 days during the second storage event. The total storage periods were 202 and 245 days, respectively, for the first and second storage events. Manure was weighed, sampled, and analyzed before it was loaded into the storage rooms and at the end of each storage event. Mass balance calculations were used to determine the losses of different components. Statistical analyses show that the nutrient contents, on a wet basis, of manure loaded in CC, AV, and EC storage rooms were significantly different due to the differences in manure moisture contents. However, on a dry basis, they had no significant differences. The fresh manure cleaned out from the EC layer house was drier than that from the other two houses. Loaded-in nitrogen losses in the CC, AV, and EC storage rooms were 24.6, 12.9, and 20.8%, respectively. Nitrogen losses depended on house temperature, manure moisture, and pH. The average losses of loaded-in manure mass, moisture, and total solids during the two storage events were 27.6?±?1.9, 33.8?±?8.3, and 20.8?±?7.0%, respectively. The losses of N, P, K, C, and S were 19.4?±?13.4, 11.7?±?5.6, 10.2?±?6.8, 27.0?±?6.5, and 8.3?±?8.5% of their loaded-in amounts, respectively. The total loss of N, P, K, C, and S was 56% of the total loaded-in solids loss; thereof, the loss of N, P, and K was 7%, and C loss was 48%. The laying-hen-specific losses of N, P, K, C, and S were 0.34, 0.05, 0.08, 3.2 and 0.019 g day?1 hen?1, respectively. The results of this research are important for assessing impacts of stored manure on environment and nutrient losses. They can also be used to develop methodologies for the mitigation of the emissions from egg production facilities.  相似文献   

12.
Fixation of Si, Mg, Fe, Al, Mn, Cr, Ni and Co in saprolite and laterite above serpentinite - Gebe Island, Indonesia The fixation of various major and trace elements has been studied in a saprolite/laterite profile above serpentinized peridotite. Sequential extraction of < 63 μm fraction shows different types of element fixation in soil: adsorption on mineral surfaces (1), fixation to Mn-oxides (2), bonding to poorly and better crystallized Fe-oxides (3). In the laterite, most of the extractable Si-, Al-, Cr- and Ni-contents are bound to goethitic Fe-hydroxide. The saprolite has considerable amounts of secondary quartz which has been formed during ageing of amorphous silica modifications. Their precipitation is favoured by high Si adsorption capacity of poorly crystallized Fe-hydroxide. In saprolite and laterite Co is bound to Mn-oxides. It can readily be extracted from pure Mn-oxides. In contrast, the intimate association of Mn-oxides to goethite reduces the rate of easily extractable Mn and Co in middle and upper zones of the laterite.  相似文献   

13.
The literature on the fluxes of six heavy metals in temperate forest ecosystems is reviewed. Special attention is given to wet and dry deposition and internal flux, to metal budgets for ecosystems and soils, to concentrations in aqueous compartments of the ecosystem and to speciation in soil solutions. Metal fluxes are discussed in relation to pollution load, soil type, tree species and land use. The mobility of Cu and Pb is strongly dependent on the solubility of organic matter. These metals are commonly accumulated in forest soils. Zinc, Cd and Ni are greatly influenced by soil acidity and are often lost in considerable amounts from acidified soils. Chromium is often at balance in forest ecosystems. Implications for metal solubility and budgets in forest soils are discussed in connection with an increase in soil acidification.  相似文献   

14.
The volatile and soil loss profiles of six agricultural pesticides were measured for 20 days following treatment to freshly tilled soil at the Beltsville Agricultural Research Center. The volatile fluxes were determined using the Theoretical Profile Shape (TPS) method. Polyurethane foam plugs were used to collect the gas-phase levels of the pesticides at the TPS-defined critical height above a treated field. Surface-soil (0-8 cm) samples were collected on each day of air sampling. The order of the volatile flux losses was trifluralin > alpha-endosulfan > chlorpyrifos > metolachlor > atrazine > beta-endosulfan. The magnitude of the losses ranged from 14.1% of nominal applied amounts of trifluralin to 2.5% of beta-endosulfan. The daily loss profiles were typical of those observed by others for volatile flux of pesticides from moist soil. Even though heavy rains occurred from the first to third day after treatment, the majority of the losses took place within 4 days of treatment, that is, 59% of the total applied atrazine and metolachlor and >78% of the other pesticides. Soil losses generally followed pseudo-first-order kinetics; however, leaching due to heavy rainfall caused significant errors in these results. The portion of soil losses that were accounted for by the volatile fluxes was ordered as follows: alpha-endosulfan, 34.5%; trifluralin, 26.5%; chlorpyrifos, 23.3%; beta-endosulfan, 14.5%; metolachlor, 12.4%; and atrazine, 7.5%.  相似文献   

15.
Different procedures have been proposed to decompose soil samples. Most of them regard determination with fertility aims. In this case, the contents available to the plants are considered. On the other hand, there are procedures to determine total content. The objective of this work was to propose a new decomposition procedure to determine barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), vanadium (V), and zinc (Zn) total content in tropical soils with high content of oxides and silicate. According to the results, the digestion procedure proposed in this study provided satisfactory results for the contents recovery for the elements Ba, Co, Cr, Cu, Mn, Ni, V, and Zn, above 90%, and the use of inverted aqua regia, hydrogen peroxide (H2O2), hydrofluoric acid (HF), pre-digestions and agitation was shown as a new alternative for the high silicate content soil sample total digestion, such as the oxisols.  相似文献   

16.
A new HPLC procedure based on hydrophilic interaction chromatography (HILIC) has been developed for the simultaneous determination of carnosine, anserine, balenine, creatine, and creatinine in meat. This is the first time that HILIC has been directly applied to the study of meat components, having the advantage of not requiring complex cleanup and/or sample derivatization procedures. The chromatographic separation has been developed using a silica column (4.6 x 150 mm, 3 microm), and the proposed methodology is simple, reliable, and fast (<13 min per sample). The method has been validated in terms of linearity, repeatability, reproducibility, and recovery and represents an interesting alternative to methods currently in use for determining the mentioned compounds and other polar substances. The detection limits are 5.64, 8.23, 3.66, 3.99, and 0.06 microg/mL for carnosine, anserine, balenine, creatine, and creatinine, respectively.  相似文献   

17.
The importance of dietary sulforaphane in helping maintain good health continues to gain support within the health-care community and awareness among U.S. consumers. In addition to the traditional avenue for obtaining sulforaphane, namely, the consumption of appropriate cruciferous vegetables, other consumer products containing added glucoraphanin, the natural precursor to sulforaphane, are now appearing in the United States. Crucifer seeds are a likely source for obtaining glucoraphanin, owing to a higher concentration of glucoraphanin and the relative ease of processing seeds as compared to vegetative parts. Seeds of several commonly consumed crucifers were analyzed not only for glucoraphanin but also for components that might have negative health implications, such as certain indole-containing glucosinolates and erucic acid-containing lipids. Glucoraphanin, 4-hydroxyglucobrassicin, other glucosinolates, and lipid erucic acid were quantified in seeds of 33 commercially available cultivars of broccoli, 4 cultivars each of kohlrabi, radish, cauliflower, Brussels sprouts, kale, and cabbage, and 2 cultivars of raab.  相似文献   

18.
Anthropogenic contributions of lead to the urban environment havebeen dominated by combustion of leaded gasoline. A number of studies have used lead concentrations in road deposited sediments(RDSs) to infer automobile contributions. However, few studies have combined concentration data, enrichment ratios, and lead isotope ratio data into a comprehensive picture of lead contamination of road sediments. An urban, non-industrialized basin, in Oahu, Hawaii, was selected for investigation. Twenty RDSsamples were collected throughout the 11 km2 system, with anundisturbed soil profile sampled to a depth of 30 cm to documentbackground lead levels.Median lead concentrations from a weak (cold) HCl digestion and a hot nitric acid digestion were 3 and 7 mg kg-1 for thebackground soil, and 256 and 303 mg kg-1 for RDSs. The median Pb enrichment ratio (HCl digestion) for RDSs was 129, witha range from 24 to 883. All the data collected point to a highlycontaminated environment.Lead isotope ratios from potential sources were examined relativeto those observed for RDSs in the system. Host geological rocks,paint, and long-range aerosol transport were ruled-out as significant sources based on an examination of isotope ratios andpotential loadings to road sediments. Leaded gasoline wasidentified as the major contributor to present-day road sedimentsbased on their radiogenic nature, with mean 206Pb/204Pb = 18.787 ± 0.096 (95% confidence interval), 207Pb/204Pb = 15.847± 0.074, 208Pb/204Pb= 38.836 ± 0.221, and 206Pb/207Pb = 1.184 ± 0.009. The contribution of gasoline additives to RDS for two periods, pre-1968 and post-1968, were estimated using 206Pb/207Pb ratios. The average contribution of post-1968 lead to RDSs was 59%, with a range from 32 to 81%. To explain the mixed age of lead in the RDSs, we suggest that erosional processes have mobilized sediment from roadside reservoirs in the basin that have accumulated automobile emissions primarily since the 1930s. The significant shift in useof radiogenic (J-type) ores, mostly from Missouri, USA, have allowed us to fingerprint and apportion lead in RDSs of thissystem.  相似文献   

19.
Abstract

An experiment was designed to evaluate several of the commonly used extractants and methods for determining “available”; elements in soils. The purpose of the study was to evaluate the suitability of these extraction procedures for use on forest soils typical for New England commercial forests. The extraction procedures selected included NH4OAc pH 4.8, NH4OAc pH 7.0, NH4Cl, Double Acid, Bray, and Mehlich methods. The elements measured varied somewhat by procedure but included the base cations, Al, Fe, Mn, and P. As a bioassay of element availability, a greenhouse study was conducted using six forest soil materials from different horizon types (i.e. O, Ap, B) and three conifer seedling species (red spruce, balsam fir, and white pine). Relatively small differences among extraction procedures were found among the methods used for exchangeable Ca, Mg, K, and Na. Large differences, however, were found among the different horizon types in the amount of exchangeable base cations present. In contrast, significant differences were found among extraction procedures for Al, Fe, Mn, and P depending on the degree of buffering and acidity of the extracting solution. Of the elements measured in this study, only P appeared to be growth limiting with the NH4OAc pH 4.8 being best correlated with P uptake by seedlings. Further work under field conditions over longer time periods is required to evaluate these methods for measuring P availability in forest soils  相似文献   

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