Fate, Transport, and Biodegradation Products of Organophosphorus Pesticides in the
Kalamazoo River and its Tributaries
GLEAMS White Paper Proposal
April 21, 2003
Principle Investigator
Dr. James J. Kiddle
Department of Chemistry
Western Michigan University
Cluster Member
Dr. Jay C. Means
Department of Chemistry
Western Michigan University
Organophosphorus pesticides (OPP) and herbicides are a diverse class of agents for the
control of a variety of pests. While organophosphorus pesticides are significantly more labile
than organochlorine pesticides, their residues are distinctly detectable in environmental
matrices.1 Surveys of surface waters in agricultural watersheds have detected the presence of
organophosphorus pesticides in a variety of aquatic systems.2 Although the organophosphorus
pesticides are more labile, biodegradation and metabolism produce compounds that are acutely
toxic to both invertebrate and vertebrate animals.3 In addition, mishandling and indiscriminate
application of organophosphorus pesticides is clearly increasing their prevalence in the aquatic
environment.4
Despite the hazards of organophosphorus pesticides to the aquatic environment, very
little is known about the chemistry of their fate and transport, as well as their biotransformations
in many aquatic systems. In fact, the stability of organophosphorus pesticides in water is still
controversial, with significantly different opinions from various governmental commissions and
surveys.5 In addition, many of the studies of the persistence of organophosphorus pesticides in
water to date were carried out under conditions not normally found in the environment,
specifically, in sterile water, under dark conditions, and at a high concentration of the pesticide.
Furthermore, the transformations of organophosphorus pesticides, in aquatic systems, to
compounds that show the acute toxic effects have not been explored.
The pathways in Scheme 1 depict common degradations/transformation routes for many
organophosphorus pesticide compounds in aquatic environments. The extent to which these
transformations occur depends greatly on the structure of the OPP and the prevailing
environmental conditions. The reaction pathways in Scheme 1 are known to occur under a
variety of hydrolytic, oxidative, and thermal conditions. These conditions have also been
described as reaction pathways occurring in the surface layer of fresh-water aquatic
environments. At present, the fate of the parent OPP compounds, and the products of
degradation/transformation in these aquatic environments is unknown. It is the specific aim of
this research to determine the distribution of the parent organophosphorus pesticides, as well as
their degradation/transformation products in the Kalamazoo River and its tributaries.
Scheme 1
O
OCH2CH3
R O P
OCH2CH3
31
P NMR  = 0 to -10 ppm
oxon-species
Hydrolysis
-O
31
O
OCH2CH3
P
OCH2CH3
P NMR  = -4.32
Oxidation
S
OCH2CH3
R O P
OCH2CH3
P NMR  = 60 to 80 ppm
parent OPP compound
31
Hydrolysis
-S
31
O
OCH2CH3
P
OCH2CH3
P NMR  = -44.0
Isomerization
O
SCH2CH3
R O P
OCH2CH3
31
P NMR  = 20 to 35 ppm
iso-species
Hydrolysis
-O
O
SCH2CH3
P
OCH2CH3
31
P NMR  = -12.68
The long term goals of this project will be to determine the environmental impact of
organophosphorus pesticides on the Great Lakes and its associated watersheds. To begin these
investigations we propose to determine the identity and, where possible, the chemical and
biological degradation products of organophosphorus pesticides utilized in the Southwest region
of Michigan along the Kalamazoo River. To accomplish these goals we plan to test water
samples from the Kalamazoo River, and its tributaries, especially those with runoff from
agricultural sources and golf courses for the presence of OPP compounds. The investigations
will use two analytical techniques, phosphorus-31 (31P) NMR spectroscopy and LC-MS (liquid
chromatography/mass spectrometry), to identify and then verify the identity of all OPP
compounds present in the water samples.
The use of 31P NMR is ideal for these compounds since their chemical shifts () show a
broad range of values. In fact, an investigation of the literature of 31P NMR chemical shifts for
organophosphorus pesticides (>50 pesticides) suggests that we can in fact distinguish between
individual organophosphorus pesticides and degradation products based solely on their 31P NMR
chemical shifts.6 Moreover, since 31P is in 100% abundance in nature, concentration data and
kinetic information about rate constants for determination of environmentally relevant chemical
reaction can be directly obtained from integration of the 31P NMR signals.7 In addition, the 31P
NMR samples do not require any preparation, like some other analytical techniques, making this
a potentially rapid method for the determination of organophosphorus pesticides in natural water
samples. However, because of a lower sensitivity then other analytical techniques NMR
spectroscopy has not been fully recognized as a general tool for the determination of these types
of data for environmental studies. Therefore, it is also proposed to examine the samples by LCMS, a well established technique for these types of studies, to verify and validate our 31P NMR
data and methodology.
The availability of these data should make an important contribution to the Geographic
Information System (GIS) mapping of contaminants and their movement in the Great Lakes and
associated watersheds. In addition, even with only limited concentration data it should be
possible to obtain information about the rate constants for the chemical transformations of the
OPP compounds outlined in Scheme 1,8 and incorporate these data about hydrolysis products
into the GIS electronic mapping. These data will be especially important since the products of
hydrolysis represented in Scheme 1 are phosphate type molecules and have been shown to
promote eutrophication of water bodies thus, having a long-term effect on the trophic status of
the receiving water bodies and indirectly the organisms present. This indirect connection to the
organisms present in the water bodies would then have a potential impact on human health in the
same region.
In summary, we propose the initiation of a comprehensive examination of the presence of
organophosphorus pesticides in the Great Lakes and its associated watersheds. The initial
investigations planned would focus on the establishment of a new method for the detection of
organophosphorus pesticides in the Kalamazoo River, and its tributaries to provide details about
the fate and transport, as well as potential biodegradation pathways for these compounds. These
data would then provide GIS mapping of these potential contaminants in the Kalamazoo River
and its tributaries. Additionally, these efforts would provide the foundation for a variety of
future collaborative research ventures that could include studies of sediments and soil samples
for organophosphorus pesticides to further expand the scope of our understanding of the fate and
transport of these compounds in the Great Lakes regions.
References
1. Racke, K.D. Degradation of Organophosphorus Insecticides in Environmental Matrices.
In Organophosphates Chemistry, Fate, and Effects; Chambers, J.E.; Levi, P.E., Eds.;
Academic Press: New York, 1992. pp 47-78.
2. Baker, D.B.; Richards, R.P. The Transport of Soluble Pesticides Through Drainage
Networks in Large Agricultural River Basins. Water Qual. Lab. Report, Heidelberg
College, Tiffin, Ohio.
3. Minton, N.A.; Murray, V.S.G. A Review of Organophosphate Poisoning. Medical
Toxicology 1988, 3, 350-375.
4. Durairaj, S.; Selvarajan, V.R. Synergistic Action of Organophosphorus Pesticides on
Fish, Oreochromis mossambicus. J. Environ. Biol. 1995, 16, 51-53.
5. Munch, D.J.; Frebis, Ch.P. Analyte Stability Studies Conducted During the National
Pesticide Survey. Environ. Sci. Technol. 1992, 26, 921-925.
6. Kiddle, J.J. unpublished results.
7. Quin, L.D.; Verkade, J.G. Phosphorus-31 NMR Spectral Properties in Compound
Characterization and Structural Analysis; VCH Publishers: New York, 1994.
8. Von Arx, K.B.; Manock, J.J.; Huffman, S.W.; Messina, M. Using Limited Concentration
Data for the Determination of Rate Constants with the Genetic Algorithm. Environ. Sci.
Technol. 1998, 32, 3207-3212.