Full free study available at http://jeq.scijournals.org/cgi/content/full/30/1/18
J Environ Qual. 2001 Jan-Feb;30(1):18-23.
In vitro pesticide degradation in turfgrass
soil incubated under open and sealed conditions.
Suzuki T, Yaguchi K, Suzuki S, Suga T.
Tama Branch Lab, Tachikawa, Tokyo, Japan. tsuzuki@tokyo-eiken.go.jp
Degradation of selected pesticides was conducted in a turfgrass
soil from a golf course under open (i.e., allowing gas exchange
with atmosphere) and sealed systems. The time required for 50%
of the initial dose of fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl
phosphorothioate), diazinon (O,O-dimethyl O-2-isopropyl-6-methylpyrimidin4-yl
phosphorothioate), iprodione [3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxo-imidazolidine-1-carboxamide],
mecoprop [(RS)-2-(4-chloro-otolyloxy)propionic acid], and asulam
(4-aminophenylsulfonyl-carbamate) to dissipate (half-life, t 1/2)
was less than 2 wk under both conditions. The t 1/2 values of
dithiopyr (S,S'-dimethyl 2-difluoromethyl-4-isobutyl-6-trifluoro-methylpyridine-3,5-dicarbothioate)
were 324 and 185 d under the open and sealed
conditions, respectively. The t 1/2 values of isoprothiolane
(di-isopropyl 1,3-dithiolan-2-ylidene-malonate), flutolanil
(alpha,alpha,alpha-trifluoro-3'-isopropoxy-o-toluanilide), and
benefin (N-butyl-N-ethyl-alpha,alpha,alpha-trifluoro-2,6-dinitro-p-toluidine)
under the open conditions were 154, 336,
and 47 d, respectively. The t 1/2 values of these pesticides increased
slightly under the sealed conditions. The t 1/2 values of terbutol
(2,6-di-tert-butyl-4-methylphenyl N-methycarbamate) and one of
the major degradation products, N-demethyl-terbutol (2,6-di-tert-butyl-4-methylphenyl
carbamate), were 182 and 291 d under the open conditions and increased
by six- and threefold under the sealed conditions, respectively.
The degradation system under the sealed conditions could characterize
the persistence of terbutol and N-demethyl-terbutol, which were
the most persistent in the field.
From Toxline at Toxnet
JOURNAL OF ENVIRONMENTAL QUALITY; 26 (2). 1997.
379-386.
Potential movement of dithiopyr following
application to golf courses.
HONG S, SMITH AE
Dep. Crop Soil Sci., Univ. Ga., Ga. Exp. Stn., Griffin, GA 30223,
USA.
BIOSIS COPYRIGHT: BIOL ABS. Research was conducted to evaluate
the potential movement of dithiopyr (S,S-dimethyl2-(difluoromethyl)-4-(2-methylpropyl)-6(trifluoromethyl)-3,5-pyridinedicarbothioate)
from golf courses. Dithiopyr was applied as granule and emulsifiable
concentrate (EC) formulations to 'Penncross' creeping bentgrass
(Agrostis stolonifera L.) and 'Tifdwarf' hybrid bermudagrass (Cynodon
dactylon (L.) Pers. Burtt-Davy) in simulated greens. Less than
0.6% of the dithiopyr was transported through the rooting media
(a mixture containing at least 97% coarse sand by weight with
sphagnum peat moss). Dithiopyr concentrations in the leachate,
transported through the greens, did not exceed 3 mug L-1. Most
of the dithiopyr (11-31%) was detected in the top 0 to 12.5 cm
of rooting media at the end of the greenhouse experiments and
as much as 20% of the applied dithiopyr was removed with the leaf
clippings over the duration of the greenhouse experiments. The
highest concentration of dithiopyr transpo [absract truncated]
From Toxline at Toxnet
203RD ACS (AMERICAN CHEMICAL SOCIETY) NATIONAL MEETING, SAN FRANCISCO,
CALIFORNIA, USA, APRIL 5-10, 1992. ABSTR PAP AM CHEM SOC; 203
(1-3). 1992. AGRO130.
POTENTIAL LEACHING OF HERBICIDES APPLIED
TO GOLF COURSE GREENS
SMITH AE
BIOSIS COPYRIGHT: BIOL ABS. RRM 2 4-D DITHIOPYR
DICAMBA PEST CONTROL WATER INFILTRATION PERCOLATION
CAS Registry Numbers:
97886-45-8
97886-45-8
1918-00-9
94-75-7
From Toxline at Toxnet
PROTOPLASMA; 179 (1-2). 1994. 16-25.
Mitotic disrupter herbicides act by a
single mechanism but vary in efficacy.
HOFFMAN JC, VAUGHN KC
Southern Weed Sci. Lab., ARS, U.S. Dep. Agric., P.O. Box 350,
Stoneville, MS 38776, USA.
BIOSIS COPYRIGHT: BIOL ABS. Although there are numerous herbicides
that disrupt mitosis as a mechanism of action, to date not one
has compared the effects of these disrupters on a single species
and over a range of concentrations. Oat seedlings, treated with
a range of concentrations of nine different "mitotic disrupter
herbicides", were examined by immunofluorescence microscopy
of tubulin in methacrylate sections. All herbicides caused the
same kinds of microtubule disruption, although the concentrations
required to cause the effects differed markedly between the herbicides.
Effects on spindle and phragmoplast mitotic microtubule arrays
were seen at the lowest concentrations and manifested as multipolar
spindles and bifurcated phragmoplasts (which subsequently resulted
in abnormal cell plate formation). At increasing concentrations,
effects on mitotic microtubule arrays manifested as microtubule
tufts at kinetochores and reduction of cortical microtubules resulting
in arrested prometaphase figure
CAS Registry Numbers:
97886-45-8
97886-45-8
23950-58-5
19044-88-3
16118-49-3
8066-92-0
3337-71-1
1918-11-2
1861-32-1
1582-09-8
122-42-9
101-27-9
101-21-3
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1958076&dopt=Abstract
Arch Environ
Contam Toxicol. 1991 Aug;21(2):195-201.
Assessment
of lawn care worker exposure to dithiopyr.
Cowell
JE, Lottman CM, Manning MJ.
Monsanto
Agricultural Company,
Environmental Science Department, St. Louis, Missouri 63198.
Eighteen ChemLawn lawn
care specialists were monitored for worker exposure by both passive
dosimetry and biological monitoring techniques in the performance
of normal duties of mixing/loading and application of Dimension
herbicide to turfgrass. Passive dosimetry was performed, utilizing
cotton gauze patches, silica gel air sampling absorption media,
and hand washes as per US Environmental Protection Agency Pesticide
Assessment Guidelines. Biological monitoring was performed by
analysis of all urine specimens collected from each specialist
from initiation until 72 h after application of dithiopyr. The
mean body dose estimate from urinalysis of the specimens collected
over the 72 h period was 4.60 x 10(-5) mg/kg/lb applied. The passive
dosimetry body dose estimates using dermal deposition measurements
corrected for skin penetration and simulated inhalation measurements
were calculated for the two clothing scenarios observed in the
worker tests. The mean body dose estimate for a fully clothed
specialist wearing a long-sleeved shirt was 8.09 x 10(-5) mg/kg/lb
while for a specialist wearing a short-sleeved shirt the estimate
was 3.62 x 10(-4) mg/kg/lb. The lower leg regions, which were
protected by long pants and boots, had the highest exposure by
passive dosimetry data.
PMID: 1958076
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1796604&dopt=Abstract
Xenobiotica.
1991 Oct;21(10):1265-71.
In vitro
transformation of dithiopyr by rat liver enzymes: conversion of
methylthioesters to acids by oxygenases.
Feng
PC, Solsten RT.
Monsanto
Agricultural Co., A Unit of Monsanto Co.,
St. Louis, MO 63198.
1. Transformation of
dithiopyr by rat liver enzymes in vitro produced the corresponding
monoacids as the predominant metabolites.
2. Transformations of the methylthioester functional groups in
dithiopyr to the monoacids were mediated via rat liver microsomal
oxygenases, and not via esterases.
3. Based on the formation of a dithiopyr-glutathione conjugate,
the mechanism of monoacid formation is believed to proceed through
an initial sulphur oxidation of the methylthioester group and
a subsequent nucleophilic displacement reaction.
PMID: 1796604
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12558106&dopt=Abstract
Pest Manag
Sci. 2003 Jan;59(1):114-8.
Dissipation
of the herbicide dithiopyr in soil and residues in wheat (Triticum
aestivum L) grain under Indian tropical conditions.
Saikia
N, Kulshrestha G.
Division of Agricultural
Chemicals, Indian Agricultural Research Institute, New Delhi,
India.
Dissipation of dithiopyr
in soil was monitored after application to wheat crop as pre-
or post-emergence applications at two rates, viz 100 and 200 g
AI ha(-1). The level of dithiopyr in the soil was assessed by
gas chromatography, and its disappearence was found to follow
a first-order decay curve irrespective of rate or method of application.
The half-life in soil ranged between 17.3 and 25.0 days and residues
at harvest (150 days after application) ranged between 4.0 and
8.8% of amounts applied. Investigation of microbial degradation
of dithiopyr was conducted in minimal salt and Czapek Dox media
in which 80% of the compound degraded within 15 days. Residues
were not detected in wheat grain at harvest.
PMID: 12558106
[PubMed - in process]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12403267&dopt=Abstract
J Environ
Sci Health B. 2002 Nov;37(6):573-86.
Adsorption-desorption,
persistence, and leaching behavior of dithiopyr in an alluvial
soil of India.
Gupta
S, Gajbhiye VT.
Division of Agricultural
Chemicals, Indian Agricultural Research Institute, New Delhi.
Investigations were
undertaken to determine the adsorption-desorption, persistence
and leaching of dithiopyr (S,S'-dimethyl 2-difluoromethyl-4-isobutyl-6-trifluoromethyl
pyridine-3,5-dicarbothioate) in an alluvial soil under laboratory
condition. The adsorption-desorption studies were carried out
using batch equilibration technique. The mass balance studies
showed that 83-97% of the pesticide was recovered during adsorption-desorption
studies. The results revealed strong adsorption of dithiopyr in
alluvial soil with Kd values ranging from 3.97-5.78 and Freundlich
capacity factor (KF) value of 2.41. The strong adsorption was
evident from the hysteresis effect observed during desorption.
The hysteresis coefficients ranged from 0.17-0.40. The persistence
studies were carried out at two concentrations (1.0 and 10.0 microg
g(-1) level) under field capacity moisture and submerged condition
by incubating the treated soil at 25 +/- 1 degrees C. In general,
dithiopyr persisted beyond 90 days with half-life varying from
11.5-12.9 days under different conditions. The rate of application
and moisture regimes had no overall effect on the persistence.
The leaching studies carried out in packed column under saturated
flow condition revealed that dithiopyr was highly immobile in
alluvial soil. Only small amounts (0.02-0.04%)
were recovered from leachate whereas major portion (99.9%) remained
in top layer of the soil column. The data suggest that strong
adsorption of dithiopyr will cause a greater persistence problem
in the soil. However, the chances of its movement to ground
water will be negligible due to its immobility.
PMID: 12403267
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11599718&dopt=Abstract
J Environ
Sci Health B. 2001 Sep;36(5):529-43.
Sorption
and mobility of dithiopyr in golf course greens rooting medium.
Hong
S, Smith AE.
Department of Crop
and Soil Sciences, College of Agricultural and Environmental Sciences,
The University of Georgia, Georgia Experiment Station, Griffin
30223, USA. sh87@cornell.edu
Sorption and mobility
of dithiopyr in golf course greens rooting medium (RM) were studied.
The sorption increased from 20 to 27 degrees C at 24 h after treatment
(HAT) and reached equilibrium in 48 HAT at 20 degrees C. The sorption
isotherms had Freundlich values (KF) of 1122, 27.44 to 35.16,
and 0.053 to 0.168 for peat moss, the RM, and quartz sand, respectively,
and solid to aqueous phase partition coefficients (Kd) of 470
to 1706 L/kg, 14.61 to 84.4 L/kg, and 0.07 to 0.29 L/kg for peat
moss, RM, and quartz sand, respectively. Generally, higher dithiopyr
concentration in the aqueous solution and the reduced pH of the
solution corresponded to the higher Kd values. The average values
for dispersion (D, cm2/min), retardation coefficient (R), beta,
and omega parameters for solute transport in the RM lysimeter;
obtained from CXTFIT curve fitting of Br- breakthrough curves;
were 0.95, 1.01, 1, and 93.89, respectively. After elutriation
by 18 L of aqueous KNO3 (10 mM), greater than 90% of the added
dithiopyr remained in the top 10 cm of the RM lysimeter and no
detectable dithiopyr was present at depths beyond 35 cm. The lysimeter
effluent contained dithiopyr at concentrations less than 3.5 microg/L.
The R value obtained from CXFIT curve fitting is 38.5. Results
from both sorption and mobility experiments indicated that dithiopyr
is quite immobile in golf course greens RM and has minimal potential
for movement into surface water drainage or ground water.
PMID: 11599718
[PubMed - indexed for MEDLINE]
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