Analysis of the Sulfonylurea Herbicide Metsulfuron-Methyl and Its Metabolites in the Soil of Cereal Crops. Comparative Analytical Chemistry of the Sulfonylureas

Abstract

For the analysis of metsulfuron-methyl in the crop soils with a sensitivity limit of 0.3 μg kg^?1 dry soil, in the soil extract metsulfuron-methyl was separated from its soil metabolites and the soil impurities by repeated thin-layer chromatographies (TLC). In the cleaned soil extract, diazomethane transformed metsulfuron-methyl 1 into N,N′ -dimethyl metsulfuron-methyl 2 (methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)methylamino]carbonyl]methylamino]sulfonyl]benzoate). In the gas-liquid chromatograph with detection by electron capture (GC-EC) and in the combined gas chromatograph-mass spectrometer (GC-MS), 2 was transformed into 1-dioxy-2-N-methyl-3-keto-1,2-benzisothiazole 3 which was measured by GC-EC with confirmation by GC-MS. The metsulfuron-methyl soil metabolites 2-sulfonamido-methylbenzoate 6, 1-dioxy-3-keto-1,2-benzisothiazole (saccharin) 7 and 2-sulfonamidobenzoic acid 8 were analyzed in the soil of winter wheat crops by a procedure similar to the one for metsulfuron-methyl. After their separation and purification in the soil extracts by TLC, 7 and 8 were methylated, and analyzed as 3 in the GC-EC and GC-MS apparatus where the generated 6 was quantitatively transformed into 3; 6 was analyzed as such with the GC and GC-MS apparatus wherein it was transformed into 3. The sensitivity limit for each metabolite was 0.3 μg of equivalents of metsulfuron-methyl kg^?1dry soil. The syntheses of the analysis standards of the metsulfuron-methyl derivatives 2 and 3, and of the metsulfuron-methyl metabolites 6, 7 and 8 are described. The transformation pathways of metsulfuron-methyl and of its derivatives are different from those of the pyridine-pyrimidine sulfonylurea herbicides flupyrsulfuron-methyl and rimsulfuron. The soil analysis of a sulfonylurea -by means of one of its transformation product- needs a previous study of the chemical reactivity of the sulfonylurea. This leads to the analysis procedures for the main soil metabolites of the sulfonylurea.     

Systematic Identification of Analytical Indicators to Measure Soil Load on Plants for Safety Assessment Purposes

Abstract

Contaminants in soil can be transferred to humans and other biota when soil dust on plants is ingested as food. Measuring how much soil is on plants, in the absence of artificial tracers or contaminants, is difficult because of the very small amounts involved and the confounding effect of absorption of elements through roots. However, measurements of soil load are essential for assessment modelling. We compared the ability of several analysis strategies, involving naturally occurring elements, to predict the soil load on plants. Large samples of 12 vegetable and fruit crops were collected, along with corresponding soil samples. An independent measure of soil load on the crop samples was derived from a combination of gravimetric measurements, including loss on washing and the acid-insoluble ash content. The best agreement between the elemental-abundance and the gravimetric methods was for Sr in the plant acid-insoluble ash. Through a systematic process of elimination, we conclude that analyses of the acid-insoluble ash fraction of the plant samples for Al, Ba, Fe, Si, Sr and Ti are most reliable. If analyses are to be restricted to the full plant ash, then the choice of analytes is restricted to Al, Fe, Si and Ti. Soil loads in our study averaged 20 mg soil kg^?1 dry plant for leafy tissues and 2 mg soil kg^?1 for fruits, and washing decreased soil loads about 1.5 fold.     

An Interlaboratory Comparison of a Standardised EDTA Extraction Procedure for the Analysis of Available Trace Elements in Two Quality Control Soils

Abstract

A standardised EDTA extraction procedure was tested collaboratively by six laboratories using two in-house reference soils identified as soil A and soil B. The extracts were analysed for Zn, Cu, Pb and Mn by Inductively Coupled Plasma Spectrometry. Concentrations of extractable elements in soil A were generally much lower than those found in soil B. All laboratories produced some extreme outlying results, most of these were produced in soil B. Results for Mn were the most variable, with a range of 63.4–100.3 μg g^?1 in soil A and 226.4–415.3 μg g^?1 in soil B. In both soils, one laboratory reported high values for Zn and Mn and, one laboratory, for soil B, produced values for all four elements which were consistently low.

If outlying results are ignored, the results from most laboratories were in reasonable agreement for all elements except Mn.     

Three-block bi-focal PLS (3BIF-PLS) and its application in QSAR

When X and Y are multivariate, the two-block partial least squares (PLS) method is often used. In this paper, we outline an extension addressing a special case of the three-block (X/Y/Z) problem, where Z sits "under" Y. We have called this approach three-block bi-focal PLS (3BIF-PLS). It views the X/Y relationship as the dominant problem, and seeks to use the additional information in Z in order to improve the interpretation of the Y-part of the X/Y association. Two data sets are used to illustrate 3BIF-PLS. Example I relates to single point mutants of haloalkane dehalogenase from Sphingomonas paucimobilis UT26 and their ability to transform halogenated hydrocarbons, some of which are found as organic pollutants in soil. Example II deals with soil remediation capability of bacteria. Whole bacterial communities are monitored over time using "DNA-fingerprinting" technology to see how pollution affects population composition. Since the data sets are large, hierarchical multivariate modelling is invoked to compress data prior to 3BIF-PLS analysis. It is concluded that the 3BIF-PLS approach works well. The paper contains a discussion of pros and cons of the method, and hints at further developmental opportunities.     

Effect of Liquid Animal Manure Application on the Solubilization of Heavy Metals from Soil

Abstract

The effect of liquid animal manure on heavy metal solubilization in soil has been studied in the laboratory; three different types of experiments were carried out:

1) aerobic and anaerobic incubation of soil/manure mixtures

2) desorption of heavy metals from soil, as affected by manure liquid fraction

3) gel permeation chromatography of soil/manure aqueous extracts to identify components responsible for heavy metal solubilization.

Alf three different approaches showed that complexation involving high molecular weight dissolved organic matter from the soil/manure matrix is (together with pH) the most important driving force for heavy metal solubilization. As a consequence, chemical and microbial processes (e.g. nitrification) that influence dissolved organic matter concentrations in the soil solution, determine the degree of heavy metal solubilization in manured soil.     

Antimicrobial substances from the rare actinomycete Nonomuraea rhodomycinica NR4-ASC07T

Nonomuraea rhodomycinica NR4-ASC07^T is a rare actinomycete isolated from soil in Sirindhorn peat swamp forest. The crude extract of its culture broth exhibited antimicrobial and anticancer against diverse human pathogens and cancer cells. The chemical investigation of the crude extract led to the isolation of two new metabolites named nonomuric acid (1) and 3-hydroxy deoxydaunorubicinol aglycone (2), along with two known bioactive compounds [ε-rhodomycinone (3) and 7-deoxy-13-dihydrocarminomycinone (4)]. Compounds 1 and 3 showed antimalarial activity with the half maximal inhibitory concentration (IC₅₀) of 8.00 and 8.88 μg mL^?1, respectively. Compound 4 inhibited growth of Mycobacterium tuberculosis and Bacillus cereus at the minimum inhibitory concentrations of 50.0 and 12.50 μg mL^?1, respectively. Every compound exhibited cytotoxicity against cancer cells tested at IC₅₀ ≥ 6.34 μg mL^?1. These finding are the first report of bioactive metabolites produced by strain NR4-ASC07^T, suggesting that rare actinomycetes are yet promising sources for novel drug discovery.     

Screening Procedure for Sodium Fluoroacetate (Compound 1080) at Sub-microgram/gram Concentrations in Soils

Abstract

Sodium fluoroacetate (Compound 1080) is readily quantitated at sub-microgram per gram concentrations in small (ca. 1 g) soil samples. Samples are ultrasonically extracted with water, which is then partitioned with hexane, and acidified prior to re-extraction with ethyl acetate. The latter is taken to dryness in the presence of triethanolamine “keeper”, and the resulting acid is derivatized with pentafluorobenzyl bromide. Quantitation is performed using a gas chromatograph equipped with an electron-capture detector. A standardized statistical protocol is used to validate a screening level of 0.2 μg Compound 1080/g soil. Difluoroacetic, trifluoroacetic, and naturally-occurring formic acids do not interfere with the determination. The recovery for Compound 1080 was 40% from soil fortified to 0.2 μg/g soil.     

Environmental Analysis of Cypermethrin and its Degradation Products After Forestry Applications

Abstract

Cypermethrin and alphamethrin ([1R, cis, αS]- and [1S, cis, αR]-cypermethrin) are pyrethroid insecticides used in agriculture, forestry, and public health hygiene. After forestry applications of cypermethrin against bark beetles diastereo- and enantioselective analyses of pyrethroid residues are performed by gas chromatography (GC) with electron capture (ECD) and mass spectrometric (MS) detection, or by achiral and chiral high performance liquid chromatography (HPLC). The major soil metabolites of cypermethrin, i.e. 2,2-dimethyl-3-(1,1-dichlorovinyl)-cyclopropylic acid and 3-phenoxybenzoic acid, are analyzed as methyl esters by GC-MS with electron-impact (EI) ionization. On spruce bark cypermethrin persists several months as surface films of 1 μg/cm^2. In soil it is detected as long as seven months after treatment at levels of 0.15–0.7 μg/g. Sunlight-induced cis, trans isomerization on bark and leaves results in an excess of trans-cypermethrin isomers. In soil cis-cypermethrin isomers are more persistent than their corresponding trans-isomers. Enantioselective HPLC demonstrates chiral discrimination of a pair of trans-cypermethrin enantiomers. Analysis of soil metabolites is less meaningful since traces of the investigated products are formed from pyrethroid residues during the extraction and derivatization procedures.     

A Review of Analytical Methods for Sulfonylurea Herbicides in Soil

Abstract

The sulfonylurea herbicides are a group of about twenty compounds used for the control of broad-leaved weeds and some grasses in cereal crops. These herbicides are non-volatile, and their water solubilities are pH dependent being greater in alkaline than in acidic solutions. Their soil adsorption is generally low, with leaching potential in alkaline field soils. Sulfonylurea herbicides are degraded in soils by both chemical and biochemical mechanisms. Chemical degradation is particularly important in acidic soils where herbicide degradation is considerably more rapid that in soils of pH > 7. Application rates in the order of 10 g ha^?1 necessitate analytical techniques capable of quantifying soil based residues in the sub μ kg^?1 levels. Analytical methodologies based on plant bioassays, and chemical extraction followed by gas chromatographic (GC), high performance liquid chromatographic (HPLC), and enzyme immunoassay techniques are described and discussed.     

Bio Availability of Polychlorinated Biphenyl Congeners in the Soil to Earthworm (L. rubellus) System

Abstract

The earthworm's (Lumbricus rubellus) uptake of polychlorinated biphenyls (PCBs) from a soil contaminated with a commercial PCB formulation (Askarel at 150 μg g^?1) and their elimination of PCBs into a low contaminated soil (15 μg g^?1) has been studied. 17 individual congeners were monitored. The uptake and the elimination rate were similar for all PCB congeners notwithstanding their different chloro-substitution pattern which suggested that bioaccumulation of PCBs in earthworms is governed by passive, possibly diffusion controlled processes. The equilibrium state in the three-phase system, soil/soil water/earthworm was reached with a half-time around 3–4 days. The soil to earthworm bioconcentration factor ranged from 4 to 20 for tetra- to octa-chlorinated biphenyls and was weakly depending on the octanol-water partition coefficient: BCF = ?(1.3?1.8) × K _OW ^(0.35?0.40).     

The Analysis and Fate of the Fungicide Fenpropimorph and Its Degradation Product Fenpropimorphic Acid in Soil by Liquid Chromatography Mass Spectrometry

Abstract

This article describes a method for extraction of soil samples and analysis with liquid chromatography and mass spectrometric detection after atmospheric pressure chemical ionisation (APCI) of the fungicide fenpropimorph and its degradation product fenpropimorphic acid. The method gives high recovery rates (about 80 %) and detection limits below 1 μg/kg soil for both compounds. The article elucidates the difference between the parent compound and the degradation product with respect to adsorption properties, where fenpropimorph with a K_d value about 161 kg/L in a sandy loam is expected to be immobile in soil while the K_d value for fenpropimorphic acid is determined to 1.3 kg/L which means a much higher mobility.

Two studies on the degradation of fenpropimorph and occurrence of the degradation product are mentioned. The first experiment is a batch experiment where fenpropimorph is mixed with the soil while the second experiment is a field study with pesticide application in normal dosage and ten times normal dosage. Both experiments demonstrate the occurrence of the degradation product in the soil during months after application.     

Four new anthraquinones from a soil actinomycete Streptomyces sp. WS-13394 and their bioactivities

Further chemical study of secondary metabolites from the soil actinomycete Streptomyces sp. WS-13394 resulted in the isolation of four new alkylated anthraquinone analogues (5–8). Their structures were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, 1D and 2D NMR. The new compounds, together with analogues obtained before (1–4), were tested for their in vitro cytotoxicity against Huh-7 and SGC-7901.     

Influence of Ca(OH)2 on the Extraction Efficiency of Nitroaromatic Compounds from Soils

High concentrations of TNT and related nitroaromatic compounds (NAC) can still be found in the soils. To evaluate the alkaline hydrolysis of NAC as a new remediation technology, two highly contaminated soils were treated under alkaline conditions using Ca(OH)₂ as base. However, instead of the expected decrease, a temporary or even permanent increase was observed for several NAC. The extent of the intensity was affected by Ca(OH)₂ concentration, suggesting the existence of desorption processes in the soil. The extent of the increase also depends on the soil investigated, the highest being observed with 1,3,5-trinitrobenzene (239 mg kg^?1 compared to the baseline concentration of 24 mg kg^?1) in the HTNT2 soil. This indicates incomplete NAC extraction and, hence, too low NAC concentrations measured in soils when conventional extraction procedures are used.     

Structure elucidation and antitumour activity of a new macrolactam produced by marine-derived actinomycete Micromonospora sp. FIM05328

Chemical investigation of a marine-derived actinomycete strain Micromonospora sp. FIM05328 isolated from a soil sample collected from the East China Sea, resulted in the discovery of a new 26-membered polyene macrolactam metabolite FW05328-1 (1), together with a known polyene with pyridone ring compound aurodox (2). The structures of compounds 1 and 2 were determined by the detailed analysis of 1D, 2D NMR and HR-TOF-MS data, along with literature data analysis. 1 and 2 exhibited excellent antiproliferative activities against KYSE30, KYSE180 and EC109 human tumour cell lines, but displayed no antibacterial activities against bacteria or fungi were tested.     

Successive Determination of pH and Ammonical Nitrogen in Soil Samples

Abstract

A new, more rapid method for the determination of pH and ammonia in soil samples is described. The pH and pNH₃ are determined in the soil suspension following a vigorous stirring of the solutions using an electro-dynamic vibrator. A very good correlation was found between pH and pNH₃ in the suspension and the filtrate demonstrating the reliability of the measurements directly on the suspension.     

Determination of Chlorfenvinphos in Soils by Microwave‐Assisted Extraction and Stripping Voltammetry with an Ultramicroelectrode

Abstract

A methodology for the determination of the pesticide chlorfenvinphos by microwave‐assisted solvent extraction and square‐wave cathodic stripping voltammetry at a mercury film ultramicroelectrode in soil samples is proposed. Optimization of microwave solvent extraction performed with two soils, selected for having significantly different properties, indicated that the optimum solvent for extracting chlorfenvinphos is hexane‐acetone (1∶1, v/v). The voltammetric procedure is based on controlled adsorptive accumulation of the insecticide at the potential of?0.60 V (vs. Ag/AgCl) in the presence of Britton‐Robinson buffer (pH 6.2). The detection limit obtained for a 10 s collection time was 3.0×10^?8 mol l^?1. The validity of the developed methodology was assessed by recovery experiments at the 0.100 µg g^?1 level. The average recoveries and standard deviations for the global procedure reached by MASE‐square‐wave voltammetry were 90.2±2.8% and 92.1±3.4% for type I (soil rich in organic matter) and type II (sandy soil) samples, respectively. These results are in accordance to the expected values which show that the method has a good accuracy.     

Extraction Chromatographic Separation of Ree and Y By P507 Containing Resin and Their Icp-Aes Determination In Chinese Soil Standard Samples

Abstract

This paper describes a procedure for the determination of REE and Y in soils by ICP-AES, the optimum conditions for separation of REE and Y from major elements have been investigated by precipitation with sodium hydroxide-triethanolamine and by extraction-chroroatography with P507 containing resin. Results are given for eight Chinese soil standard samples GSS-1 to GSS 8 and compared with recommended values.     

Chemical Characterization of Silage Effluents and their Influence on Soil Bound Heavy Metals

Abstract

Silage effluents, generated during silaging of various crops, are produced in high amounts in cattle breeding farms. Due to their acidity and high content of dissolved organic matter, they are causing disposal problems. On the other hand, their ability to mobilise soil bound trace elements (i.e. heavy metals) might be useful for the decontamination of polluted soils.

With an aim to perform metal leaching studies, silage effluents from various ensiled crops (maize, rape, grass, clover, sugar-beet leaves) were collected from Bavarian farms and analysed for their main inorganic and organic constituents. Important TOC sources (TOC concentrations from 13.9 to 53.6 gl^?1) are short chain aliphatic acids (concentrations between 235 and 638 mM·D1^?1; predominant compound: lactic acid), amino acids (ranging from 22.8 to 151 mM·D1^?1) and polypeptides (concentrations from 3.8 to 20.0 g·D1^?1).

The release of heavy metals from two adsorbents (bentonite and peat) and from a polluted soil under the influence of silage effluents was studied in batch tests. The leaching efficiencies for the soil bound metals increase following the order: sugar-beet leaves < clover < maize < rape < grass. The extraction rates obtained with grass silage juice are: Cd 74.7%, Zn 55.7%, Cu 53.5%, Ni 38.9%, Cr 12.7% and Pb 8.9%. After neutralisation the leaching rates dropped, with the exception of copper.     

Comparison of Multicomponent Determination of Iprodione,Procymidone and Chlorothalonil by Partial Least Squares Modelling Using Spectrophotometric and High-Performance Liquid Chromatography Data

Abstract

A Partial Least Squares (PLS) calibration method was applied to the simultaneous determination of iprodione, procymidone and chlorothalonil in mixtures, by uv-vis absorption spectrophotometry and by high performance liquid chromatography (HPLC). Signals and first-derivative (¹D) signals were used to optimize the calibration matrices by the PLS-1 method. Quantitative results are presented for synthetic mixtures and for extracts from soil and groundwater samples. Significant improvements were achieved by using the PLS-1 method built with first-derivative chromatograms, in the determination of iprodione, procymidone and chlorothalonil in environmental samples.     

Speciation of Heavy Metals in Sewage Sludge and Sludge-Amended Soil

Abstract

The presence of heavy metals in sewage sludge restricts their agricultural use. Sequential extraction procedures may provide an assessment of the mobility of these elements in sludge and sludge-amended soil, and may help to predict the release of metals in soil solution. Nevertheless, the “phases” in which an element occurs are operationally defined and it is necessary to standardize a procedure in order to allow the comparison of result from different laboratories.