Soil metabolites

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

This analytical method determines levels of major oxanilate and sulfonate soil metabolites of acetochlor, alachlor, and metolachlor in groundwater and surface water. The method consists of analysis of environmental samples by direct aqueous injection reversed-phase LC/MS/MS. 

Limits of detection for each of the six soil metabolites in surface water and ground-water were determined by using an estimate of variability for the 0.25 pgL fortifications from samples analyzed along with hundreds of surface water and groundwater sets during the years 1999-2001. During these years, the estimated LODs were below 0.1 ug for acetochlor sulfonic acid, acetochlor oxanilic acid, alachlor oxanilic acid, metolachlor sulfonic acid, and metolachlor oxanilic acid and about 0.1 igL for alachlor sulfonic acid. If the actual concentration of an analyte is at this detection limit or greater, there is at least a 95% chance of detection. 

LOQs for each of the six soil metabolites in surface water and groundwaters were determined using analytical results (not corrected for background) of samples fortified at the lowest fortification level, 0.25 igL during the analysis in years 1999-2001. The calculated LOQs for acetochlor oxanilic acid, metolachlor sulfonic acid and metolachlor oxanilic acid are below 0.25 ig L. The calculated LOQs for acetochlor sulfonic acid, alachlor sulfonic acid, and alachlor oxanilic acid are below 0.10 igL. If the true concentration of an analyte is at the LQQ or greater, the standard error of individual measured concentration values relative to the true concentration is at most 10%. 

Biological. In an anaerobic medium, the bacteria of the Paracoccus sp. converted 4-chloroaniline to l,3-bis(/t-chlorophenyl)triazene and 4-chloroacetanilide with product yields of 80 and 5%, respectively (Minard et al., 1977). In a field experiment, [ C]4-chloroaniline was applied to a soil at a depth of 10 cm. After 20 wk, 32.4% of the applied amount was recovered in soil. Metabolites identified include 4-chloroformanilide, 4-chloroacetanilide, 4-chloronitrobenzene, 4-chloronitrosobenzene, 4,4 -dichloroazoxybenzene, and 4,4 -dichloroazobenzene (Freitag et al, 1984). 

Oat plants were grown in two soils treated with [ C]p,//-DDT. Most of the residues remained bound to the soil. Metabolites identified were /5,/7-DDE, o,//-DDT, TDE, DBF, dicofol, and DDA (Fuhremann and Lichtenstein, 1980). 

Soil Metabolites of endosulfan identified in seven soils were endosulfan diol, endosulfanhydroxy ether, endosulfan lactone, and endosulfan sulfate (Dreher and Podratzki, 1988 Martens, 1977). Endosulfan sulfate was the major biodegradation product in soils under aerobic, anaerobic, and flooded conditions. In flooded soils, endolactone was detected only once, whereas endodiol and endohydroxy ether were identified in all soils under these conditions. Under anaerobic conditions, endodiol formed in low amounts in two soils (Martens, 1977). These compounds, including endosulfan ether, were also reported as metabolites identified in aquatic systems (Day, 1991). Endosulfan sulfate was the major biodegradation product in soils under aerobic, anaerobic, and flooded conditions (Martens, 1977). In flooded soils, endolactone was detected only once whereas endodiol and endohydroxy ether were identified in all soils under these conditions. Under anaerobic conditions, endodiol formed in low amounts in two soils (Martens, 1977). 

CASRN 30560-19-1 molecular formula C4H10NO3PS FW 183.16 Soil. lu aerobic aud auaerobic soils, methamidophos aud carbou dioxide were ideutified as major soil metabolites (Hartley aud Kidd, 1987). The estimated half-life iu soil is 3 d (Wauchope, 1988). 

In aerobic soils, aldicarb degraded rapidly (half-life = 7 d) releasing carbon dioxide. Mineralization half-lives for the incubation of aldicarb in aerobic and anaerobic soils were 20-361 and 223-1,130 d, respectively. At an application rate of 20 ppm, the half-lives for aldicarb in clay, silty clay loam, and fine sandy loam were 9, 7, and 12 d, respectively (Coppedge et al, 1967). Other soil metabolites may include acids, amides, and alcohols (Hartley and Kidd, 1987). 

CASRN 314-40-9 molecular formula C9Hi3BrN202 FW 261.12 Soil Metabolites tentatively identified in soil were 5-bromo-3-(3-hydroxy-l-methylpropyl)-6-methyluracil, 5-bromo-3-5ec-butyl-6-hydroxymethyluracil, 5-bromo-3-(2-hydroxy-l-methylprop-yl)-6-methyluracil, and carbon dioxide. The presence of uracil products suggests that bromacil was degraded via hydroxylation of the side chain alkyl groups. In the laboratory, 25.3% of C-bromacil degraded in soil to carbon dioxide after 9 wk but mineralization in the field was not observed. The half-life of bromacil in a silt loam was 5-6 months (Gardiner et al, 1969). 

Soil. Metabolites identified in soil were l,3-dicyano-4-hydroxy-2,5,6-trichlorobenzene, 1,3-di-carbamoyl-2,4,5,6-tetrachlorobenzene, and l-cart3amoyl-3-cyano-4-hydroxy-2,5,6-trichlorobenz-ene (Rouchaud et al., 1988). The half-life varied from 4.1 d (Gilbert, 1976) to 1.5-3 months (Hartley and Kidd, 1987). 

CASRN 1982-47-4 molecular formula C15H15CIN2O2 FW 290.75 Soil Hartley and Kidd (1987) reported 4-(4-chlorophenoxy)aniline as a soil metabolite. Chloroxuron was degraded by microorganisms in humus soil and a sandy loam forming -(4-chlorophenoxy)phenyl-A-methylurea, W-(4-chlorophenoxy)phenylurea, and 4-(4-chlorophenoxy)-aniline, and two minor unidentified compounds (Geissbiihler et al., 1963). Residual activity in soil is limited to approximately 4 months (Hartley and Kidd, 1987). 

CASRN 52315-07-8 molecular formula C22H19CI2NO3 FW 416.30 Soil. The major soil metabolite was 3-phenoxybenzoic acid (Hartley and Kidd, 1987). Chemical/Physical. The hydrolysis half-lives of cypermethrin in a sterile 1% ethanol/water solution at 25 °C and pH values of 4.5, 6.0, 7.0, and 8.0, were 99, 69, 63, and 50 wk, respectively (Chapman and Cole, 1982). 

Soil. Soil metabolites include formaldehyde, hydrogen sulfide, methylamine, and methyl(methylaminomethyl)dithiocarbamic acid (Hartley and Kidd, 1987), the latter decomposing to methyl isothiocyanate (Ashton and Monaco, 1991 Hartley and Kidd, 1987 Cremlyn, 1991). The rate of decomposition is dependent upon the soil type, temperature, and humidity (Cremlyn, 1991). 

Soil. The major soil metabolite is 2,6-dichlorobenzamide which degrades to 2,6-dichloro-benzoic acid. The estimated half-lives ranged from 1 to 12 months (Hartley and Kidd, 1987). Under field conditions, dichlobenil persists from 2 to 12 months (Ashton and Monaco, 1991). The disappearance of dichlobenil from a hydrosol and pond water was primarily due to volatilization and biodegradation. The times required for 50 and 90% dissipation of the herbicide from a hydrosol were approximately 20 and 50 d, respectively (Rice et al., 1974). Dichlobenil has a high vapor pressure and volatilization should be an important process. Williams and Eagle (1979) found... 

Koskinen, W.C., Leffler, H.R., Oliver, J.E., Kearney, P.C., and McWhorter, C.G. Effect oftrifluralin soil metabolites on cotton boll components and fiber and seed properties, J. Agric. Food Chem., 33(5) 958-961, 1985. 

Captan accounted for 84% of the extractable radioactivity in soil. None of the polar soil metabolites could be identified. 

Rasanen, L., Hattula, M.L. Arstila, A.U. (1977) The mutagenicity of MCPA and its soil metabolites, chlorinated phenols, catechols and some widely used slimicides in Finland. Bull, environ Contam. Toxicol., 18, 565-571... 

Baker, D.B., RJ. Bushway, S. Adams, and C. Macomber (1993). Immunoassay screens for alachlor in rural wells False positives and an alachlor soil metabolite. Environ. Sci. Technol., 27 562-564. 

Soil. DT50 in soil 17-61 days, depending on the formulation type. The major soil metabolites are the di-acid, the normal mono-acid and the reverse mono-acid these metabolites, themselves, dissipate almost completely within 1 year... 

Soil. Readily biodegraded and non-persistent soil DTJ0 2 days (aerobic) to 7 days (anaerobic). Methamidophos (q.v.) has been identified as a soil metabolite... 

Soil. The most important metabolic steps were oxidation at the imidazolidine ring, reduction or loss of the nitro group, hydrolysis to 6-chloronicotinic acid and mineralisation. Medium adsorption to soil, imidacloprid and soil metabolites are to be classified as immobile... 

Plants. Besides 4-aminophenol, benzothiazolone and benzothiazoylacetic acid are found, both of which are formed by hydroxylation Soil. Metabolites formed are benzothiazole and benzothiazolyl-acetic acid... 

Figure 1. Structures of clomazone, the amino analog and the soil metabolite of clomazone.

It was of particular interest to determine whether soil metabolites of alachlor would show significant antibody reactivity, since such metabolites might occur in environmental samples for which alachlor ELISA analysis could be used. The two major soil metabolites of alachlor have been identified as the oxanilic (11) and sulfonic acids (12) (IQ). The cross-reactivity of the antibodies for these compounds was found to be 2.5% and 2.3%, respectively (Figure 3). 

The hydroxyatrazine metabolites (Fig. 6.13) are cationic, polar compounds that are cations at a pH near their pA", (- 5). They are polar compounds that are not isolated by C-18 or SDB. They may be effectively isolated from water samples by cation exchange and quantified by HPLC. They are the major soil metabolites of the triazine herbicides. 

Analysis (Residues on Crop, Residues in Soil, Metabolites)... 

The reductive half-reaction is again similar to that of DAAO and MAO and includes the oxidation of sarcosine to the corresponding imino product, which is hydrolyzed to form glycine and formaldehyde. Sarcosine, a common soil metabolite, can be used as the sole source of carbon and energy for many microorganisms. ... 

Exposure to pesticides may occur in a variety of different ways including worker exposure during manufacture, during transport, and exposure to residues in edible crops, soil and water. Adverse effects on man may result from the compound itself, its mammalian metabolites, plant and soil metabolites or, possibly, from breakdown products in the environment. Pesticides are often dispersed widely in the environment as stable materials, such as DDT, which may remain as virtually permanent contaminants, though at detectable concentrations. This, together with the fact that pesticides are highly biologically-active molecules, requires a fine balance to be set between the benefits of pesticides and their possible hazard to man or the environment. 

---