U.S. Environmental Protection Agency
Revised OP (Organophosphate)
Cumulative Risk Assessment
June 10, 2002
ffl. Appendices
•
E. Water Exposure Assessment (sections 1-6)
This document was only published electronically.
Accessed 1/14/04 from:
http://www.epa.gov/pesticides/cumulative
Cover page created by EPA Region 9 Library staff, January 14, 2004.
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I. Appendices
E. Water Appendix
1. Comparisons of Estimated Regional OP Pesticide Distributions with
Occurrences in Ambient Waters from the USGS NAWQA Program
O
OPP conducted refined surface water modeling to estimate potential OP
cumulative exposure in drinking water. These estimates represent combined OP
concentrations in untreated surface water sources of drinking water. As a part of
^ its evaluation, OPP compared estimated OP concentrations in water to available
surface water monitoring data. The most extensive source of monitoring data for
multiple pesticides is the USGS NAWQA program. NAWQA included nine OP
pesticides that are part of the OP cumulative risk assessment: azinphos-methyl,
chlorpyrifos, diazinon, disulfoton, ethoprop, malathion, methyl parathion, phorate,
and terbufos. Not every OP was included in each regional assessment, which
represents a drinking water source that is potentially vulnerable to cumulative OP
impacts. Only chlorpyrifos was included in each of the regional assessments.
Similarly, only those OP pesticides used in the vicinity of monitoring stations
have the potential to be found in each of the NAWQA study units.
While comparisons of the estimated concentrations with ambient water
monitoring are valuable in evaluating and characterizing the OP cumulative
CO | drinking water exposure assessment, certain limitations need to be
ox | acknowledged:
CD I Q This is not a comparison of the same water bodies. The estimated cumulative
> I OP concentrations used in.the regional exposure assessments represent
+-1, \ concentrations that would occur in a reservoir, and not in the streams and
J2 I rivers represented by the NAWQA sampling.
13 I
C I Q The sampling frequency of the NAWQA study (sample intervals of 1 to 2
-~ [ weeks apart or less frequent) was not designed to capture peak
Ol concentrations, so it is unlikely that the monitoring data will include true peak
I concentrations. This may be particularly critical for pesticides such as phorate
p I or terbufos, where the estimated pulse load of the parent is of a relatively
O*"*" i short duration.
|
Q The estimated concentration profile represents a wide distribution of weather
patterns (19 to 35 years), while the NAWQA data reflect a smaller time
C/} window (generally up to 3 years). Thus, the estimated profile may better
*£ I characterize the year-to-year fluctuations in weather patterns than is seen in
I the shorter time frame of the NAWQA study.
Q Several regionally-significant OP pesticides were not included in the NAWQA
study, so direct comparisons are not possible. Several significant
I.E.I Page 1
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I transformation products, in particular the sulfone and sulfoxide products of
i disulfoton, phorate, and terbufos, were also not included in NAWQA.
. 1 Q The NAWQA study did not focus on drinking water, and monitoring reflect a
I range of ambient waters. OPP tried to focus on those sampling sites that fed
CM | into drinking water sources or were reflective of drinking water sources in the
O I region.
I The significance of detections or non-detections in the monitoring data
-*«-. i depends partially on the persistence and activity of the parent compound versus
CO i the metabolites. Given the frequency of sampling, NAWQA is more likely to
i I detect a persistent OP pesticide than a nonpersistent one if they are indeed
-t-* | present in water. Relatively persistent and active OP compounds in the NAWQA
£- 1 tored in NAWQA include diazinon, chlorpyrifos, ethoprop, and azinphos methyl.
Of | Diazinon and chlorpyrifos, also with the most widespread use, were the most
£ 1 frequently detected compounds. Malathion is not considered to be persistent but
(/) I was observed frequently. It is used as an adulticide and was detected most
(/> I frequently in mixed and urban areas.
CD I
U) I However, compounds such as phorate, terbufos, and disulfoton have
1 generally non-persistent parent compounds, and rapidly form persistent and toxic
[ sulfoxide and sulfone metabolites. The NAWQA data analyzed do not contain
_y [ analyses for sulfoxide and sulfone metabolites, and there were generally few or
(/) 1 no detections of the parent compounds. As illustrated in Region A, the likely
I short pulse of the parent phorate may be missed in bi-weekly sampling. It is
\ possible that exposure to total toxic residues (parent + sulfoxide + sulfone) is
0 I likely underestimated. Similarly, a non-detection of a parent compound may not
> | signify that toxic residues of a particular pesticide are not present in a sample.
3 i Consequently, exposure to total toxic residues is also likely to be
CD [ underestimated.
1
| This appendix is divided into seven sections - one for each of the regions in
I the OP cumulative risk assessment. Each of those regional sections are divided
| into two parts. The first part provides a comparison of the estimated
I concentration distributions for the OP pesticides included in the exposure
I assessment. The second part summarizes the USGS National Water Quality
- | Assessment (NAWQA) program study units found in the regions.
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a. Region A: Florida
The major contributor to the estimated OP cumulative exposure in this
reagion was phorate use on sugarcane. Minor contributions came from
phorate use on corn and ethoprop use on sugarcane. Table III.E.1-1
summarizes the estimated distribution profile for OP pesticide included in the
exposure assessment. More detailed discussion and analysis of the OP load
in drinking water sources can be found in section 11.A.
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Table III. E. 1-1. Predicted percentile concentrations of individual OP pesticides
and of the cumulative OP distribution in the Florida Region.
Chemical >
Acephate
Chlorpyrifos
Diazinon
Ethoprop
Methamidophos
Phorate(ttl)
WCrbp/Use*'^
Peppers
Corn, Citrus
Lettuce, Tomato
Sugarcane
Peppers,
Tomato
Corn,.
Sugarcane
OP Cumulative (in
Methamiiophos Equivalents, ppb)
„ v,» -^t^H^y^K '41^ Concentration 4rituVK(Ppb)WiPSPi?fi
X'MaxS*
7.76-02
2.06-01
2.9e-02
1.5e+00
9.36-03
1.2e+01
1.46+01
•I 99th^
6.86-03
9.66-02
1.56-02
5.1e-01
1.76-03
7.2e-01
9.06-01
?>95th,i^
8.56-04
4.96-02
9.16-03
2.56-01
2.66-04
1.86-02
7.86-02
*v90th4$s
2.86-04
3.36-02
6.46-03
1.7e-01
8.4e-05
1.16-04
3.6e-02
•lS80tlt"%
8.7e-05
2.1e-02*
4.0e-03
9.86-02
1.66-05
5.4e-09
2.06-02
5.76-05
1.86-02
3.36-03
8.0e-02
9.96-06
8.5e-1 1
1.76-02
4.3e-06
9.16-03
1.16-03
3.8e-02
1 .86-07
4.46-12
8.1e-03
i. Comparison of Monitoring Data versus Model Estimates
The South Florida (SOFL) NAWQA study unit includes the vulnerable
drinking-watersheds of the Florida Region. The estimated concentrations of
chlopryrifos were similar to the detections reported from agricultural sampling
stations, with 80th percentile and greater estimated concentrations 5 to 8
times greater than similar percentiles of reported detections. Estimated 99th
percentile concentrations for diazinon were similar to that measured in the
SOFL unit. No comparisons could be made at lower percentiles, which
extended beyond the frequencies of detection for these chemicals. While 90th
and 95th percentile estimates for ethoprop were 20 to 30 times greater than
similar percentiles from the SOFL unit, 99th and maximum estimates were
closer (6 to 7 times greater). The study reported no detections of the parent
phorate. While the estimated 99th percentile concentration of total phorate
residues (including sulfone and sulfoxide) was more than two orders of
magnitude greater than the limit of detection (LOD) for phorate, the LOD fell
between the 90th and 95th percentile of the estimated distribution.
Figure 11 I.E. 1-1 compares the estimated percentile concentrations for
ethoprop with the monitoring percentiles from the Hillsboro Canal at S-6 near
Shawano. The estimated and observed levels of ethoprop in the Hillsboro
Canal were similar with the exception of the maximum concentrations.
I.E.1 Page3
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Estimated
Hillsboro Canal
10 20 30 40 50 60 70 80 90 100110
Percentile
Figure III.E. 1-1. Comparison of observed and estimated ethoprop concentrations
in the Florida Region.
ii. Summary of NAWQA Monitoring Data in the Region
The Southern Florida (SOFL) NAWQA study unit includes the Biscayne
aquifer, the Everglades, and portions of the Flatwoods and highly vulnerable
Central Ridge regions of Florida. The Floridan, surficial and intermediate
aquifers are also important sources of drinking water in this study unit.
Ground water supplied 94% of water used in the study unit in 1990 (USGS
Circular 1207).
Intensive surface water sampling in the SOFL study unit included canals
draining mixed use (vegetables), citrus and sugar cane fields. Diazinon and
chlorpyrifos were detected at low concentrations in the mixed use canal.
Chlorpyrifos(max 0.023ug/l) and malathion (max 0.084 ug/l) were detected in
25% and 20% of samples from the citrus canal, with fewer detections of
azinphos-methyl, methyl-parathion and ethoprop. Ethoprop was extensively
(32%) detected in the sugarcane canal, with a maximum concentration of
0.279 ug/l. Chlorpyrifos, methyl parathion, diazinon and malathion were
detected less frequently, and at lower concentrations. Sugarcane is the most
important use for ethoprop. Although the sugarcane canal is not used for
drinking water, this targeted monitoring indicates transport of ethoprop from
the fields can be expected to occur.
The Georgia-Florida Coastal Plain (GAFL) NAWQA study unit extends
from central Florida south of Tampa to just north of Atlanta, Georgia. The
USGS reports that 80% of the population in this area derives its drinking
water from ground water, and that 94% of that ground water is drawn from
the Upper Floridan aquifer. About 25% of this region is devoted to agriculture,
I.E.1 Page 4
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and more than half to forestry. Most of the Georgia portion of the study unit is
located within the Coastal Inlands Farm resource Region.
Surface-water monitoring in the GAFL study unit were located in Georgia,
outside of the Fruitful Rim, SE Farm resource Region. Sampling in Florida
included intensive sampling from an urban stream in Tallahassee, and a
number of fixed stream-sampling stations. Diazinon and chlorpyrifos were
detected frequently (54% and 45%) in urban and mixed land-use samples.
Malathion was detected in 35% of urban stream samples, but not in mixed
land-use samples, with a maximum concentration of 0.2 ug/l. Ethoprop,
phorate, azinphos-methyl and diazinon were detected in 3 or fewer
agricultural samples each, at concentrations <0.1 ug/l.
Table III.E. 1-2. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units Found in the Florida Region.
Land Use
, Value ; Lhlorpy/jfos
diazinon
.disul^|!%kffp
G^t!%
azinpfios,
">- methyl «
"jnethyj-1
pargthton
•• " t- *?*•.;• >-e ^^Concentation(ug./L)^**"3?>-^ •*> W^JKSMWl
Southern Florida
All
Locations
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.023
0.012
0.006
0.005
0.004
0.004
0.004
14.7%
0.014
0.005
0.002
0.002
0.002
0.002
0.002
2.0%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.279
0.075
0.012
0.005
0.003
0.003
0.003
10.0%
0.023
0.012
0.006
0.005
0.004
0.004
0.004
14.5%
Reference
Mixed
Canal-
CHI (Ag)
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
0.005
0.005
0.005
0.004
0.004
0.004
0.004
9.1%
0.005
0.005
0.002
0.002
0.002
0.002
0.002
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.014
0.014
0.013
0.013
0.005
0.004
0.002
27.3%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.279
0.094
0.014
0.005
0.003
0.003
0.003
9.0%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.003
0.003
0.003
0.0%
0.084
0.027
0.026
0.005
0.005
0.005
0.005
8.0%
0.084
0.027
0.025
0.005
0.005
0.005
0.005
8.1%
0.070
0.050
0.035
0.001
0.001
0.001
0.001
1 .6%
0.070
0.050
0.025
0.001
0.001
0.001
0.001
1 .4%
0.060
0.022
0.006
0.006
0.006
0.006
0.006
2.0%
0.060
0.023
0.006
0.006
0.006
0.006
0.006
1 .8%
0.015
0.0132
0.006
0.005
0.005
0.005
0.005
5.3%
0.027
0.027
0.027
0.027
0.005
0.005
0.005
0.0%
0.023
0.014
0.008
0.006
0.005
0.005
0.004
0.005
0.005
0.005
0.002
0.002
0.002
0.002
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.084
0.073
0.027
0.026
0.006
0.005
0.005
0.0421
0.03470
2
0.00511
0.001
0.001
0.001
0.001
5.3%
0.050
0.050
0.050
0.050
0.001
0.001
0.001 .
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.070
0.053
0.050
0.029
0.001
0.001
0.001
0.040
0.026
0.006
0.006
0.006
0.006
0.006
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
I.E.1 Page5
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» i* « ^ ,^^
A.Value ",_,
chlorpyrifos
diazinon
disulfoton
ethoprop
,f , , i £*•>•' »,.,„> ..",•-'„ v , ~t*v,-Concentation (ug
Frequency 25.6% 0.0% 0.0% 1.2%
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
L) . , , , -,„,.,
19.8% 3.5% 2.3% 0.0% 0.0%
Hillsboro
Canal (Ag)
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.007
0.006
0.004
0.004
0.004
0.004
0.004
10.8%
0.005
0.003
0.002
0.002
0.002
0.002
0.002
1.4%
0.021
0.018
0.017
0.017
0.017
0.017
0.017
0.0%
0.279
0.215
0.033
0.024
0.011
0.009
0.003
32.4%
0.027
• 0.011
0.005
0.005
0.005
0.005
0.005
1.4%
0.050
0.050
0.001
0.001
0.001
0.001
0.001
0.0%
US Sugar
Outflow
(Ag)
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.060
0.024
0.006
0.006
0.006
0.006
0.006
4.1%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.004
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.014
0.013
0.013
0.013
0.013
0.013
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
/
Florida Portion of GA-FL Coastal Plain
All
Locations
Urban/
Residential
Maximum
99th
95th
90th
80th
75th
50th
Frequency
-
Maximum
99th
95th
90th
80th
75th '
50th
Frequency
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.028
0.024
0.016
0.011
0.008
0.006
0.004
45.1%
0.276
0.244
0.101
0.084
0.058
0.051
0.008
54.2%
0.060
0.019
0.017
0.017
0.017
0.017
0.017
0.0%
0.073
0.012
0.005
0.003
0.003
0.003
0.003
3.5%
0.204
0.086
0.020
0.012
0.006
0.005
0.005
18.8%
0.054
0.051
0.001
0.001
0.001
0.001
0.001
2.1%
0.035
0.035
0.006
0.006
0.006
0.006
0.006
0.0%
0.031
0.016
0.002
0.002
0.002
0.002
0.002
1.4%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.028
0.0265
0.01725
0.0155
0.011
0.01
0.004
52.6% ,
0.006
0.006
0.005
0.005
0.004
0.004
0.004
56.8%
0.276
0.2737
5
0.1632
5
0.1005'
0.081
0.0727
5
0.0445
92.1%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.083
0.076
0.038
0.004
0.002
0.002
0.002
15.9%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.007
0.0055
0.003
0.003
0.003
0.003
0.003
2.6%
0.204
0.117
0.0364
0.02
0.011
0.009
0.005
35.5%
0.073
0.044
0.003
0.003
0.003
0.003
0.003
6.8%
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.031
0.022
0.002
0.002
0.002
0.002
0.002
4.5%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
"O
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I.E.1 Page 6
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b. Region B: Northwest
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Ethoprop had the highest estimated concentrations in the region (Table
III.E.1-3), while dimethoate, azinphos methyl, and chlorpyrifos also
contributed to the estimated peak OP cumulative load. More detailed
discussion and analysis of the OP load in drinking water sources can be
found in section II.B.
Table III.E.1-3. Estimated percentile concentrations of individual OP pesticides
and of the cumulative OP distribution in the Northwest Region.
* * *
Chemical ] "0
> »<
Acephate
Azinphos
Methyl
Bensulide
Chlorpyrifos
Diazinon
DDVP
Dimethoate
Disulfoton
Ethoprop
Malathion
Methamidophos
Methidathion
Methyl
Parathion
Naled
ODM
Phosmet
SSffi&Wffi
v 5A «**§*%«" »,«k,:*.^<'
Cauliflower, nursery, mint
Apples, pears, cherries,
blackberry
Broccoli, cabbage,
cucumbers
Fruit/nut trees, cole crops,
onions, corn, grass, trees,
mint
Fruit trees, legumes, cole
crops, onions, nursery,
hops, berries
Naled degradate
Fruit trees, legumes, cole
crops, Christmas trees
Broccoli
Beans, snap
Apples, cherries, squash,
onions, berries
Acephate degradate
Pears
Onions
Cole crops
Cabbage, Christmas Trees
Fruit trees
OP Cumulative Concentration in
Methamidophos Eauivalents, ODD
5.0e-04
7.5e-03
4.0e-02
6.06-02
1 .4e-02
8.2e-05
2.8e-02
1.16-04
7.2e-01
1.5e-02
7.3e-05
1.36-04
1.96-04
1.4e-04
7.0e-04
1.76-03
1.46-01
Jt^Rtfli-
3.6e-04
2.2e-03
3.26-02
2.76-02
9.96-03
2.8e-08
2.5e-03
8.26-05
6.66-01
2.7e-03
1.5e-06
5.56-05
5.06-05
3.56-06
1.46-04
1.16-04
1.26-01
1.9e-04
9.8e-04
2.56-02
1 .66-02
7.0e-03
2.16-12
6.86-04
6.16-05
5.16-01
9.2e-04
6.46-09
2.86-05
1 .9e-05
2.66-10
5.26-05
1.66-06
9.26-02
7.86-05
6.7e-04
2.2e-02
1.36-02
5.86-03
4.96-13
3.26-04
5.26-05
4.16-01
2.6e-04
1.36-10
1.66-05
1 .2e-05
1.36-12
3.16-05
1.86-08
7.56-02
9.8e-06
4.1e-04
1.86-02
9.8e-03
4.3e-03
1.56-13
1.26-04
4.16-05
2.86-01
3.2e-05
2.06-12
5.76-06
5.1e-06
7.26-13
1.66-05
1.96-11
5.16-02
4.4e-06
3.6e-04
1. 7e-02
8.86-03
3.96-03
9.6e-14
5.8e-05
3.66-05
2.5e-01
8.1e-06
7.1e-13
3.56-06
3.56-06
6.06-13
1.36-05
2.26-12
4.66-02
1.7e-08
2.1e-04
1.36-02
5.16-03
2.4e-03
1.76-14
6.56-06
2.2e-05
1.66-01
4.56-11
8.16-15
3.06-07
5.4e-07
S.Oe-13
3.2e-06
3.76-13
3.06-02
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i. Comparison of Monitoring Data versus Model Estimates
Six OP pesticide parent compounds included in this assessment were
tracked in the NAWQA study for the Willamette Valley. The upper percentile
estimated concentrations for four individual OP pesticides were less than the
maximum 'detections reported in the NAWQA monitoring for the Willamette
Valley. Estimated azinphos methyl concentrations were two three orders of
magnitude lower than reported detections at all percentiles. Estimated
malathion concentrations were also one to two orders of magnitude lower
than reported detections at all percentiles. Estimated diazinon concentrations
were an order of magnitude lower than reported detections at the 95th and
greater percentiles. Estimated concentrations for chlorpyrifos were similar to
reported detections at all percentiles. The highest monitoring detect of
I.E.1 Page?
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ethoprop is three times the estimated maximum peak. Neither disulfoton nor
methyl parathion were detected in the Willamette Valley study. The entire
estimated distributions for disulfoton and methyl parathion were below the
limits of detection.
All of the maximum monitoring detects occurred in Zollner Creek. This
stream has a watershed with 99% agricultural use. A comparison of
distributions showed that estimated OP concentrations at percentiles of 80th
or greater were generally lower (up to 2-3 orders of magnitude) than reported
monitoring distributions in Zollner Creek. At lower percentiles, the
concentration profiles were similar.
When the estimated concentrations are compared with the NAWQA
monitoring for rest of the agricultural watersheds (with particular focus on
Pudding River) in the Willamette Valley, the estimated concentrations were
similar to the monitoring concentrations, except for azinphos methyl and
diazinon, which were still an order of magnitude lower than maximum
monitoring detections.
Zollner Creek and the Pudding River had all but two detections in the
agricultural sites. For chlorpyrifos (Figure III.E.1-2), the estimated and
observed concentrations were consistent except that the observed
concentrations in Zollner Creek were higher at the highest percentiles. For
ethoprop (Figure III.E.1-3), the estimated concentrations were slightly higher
than the observed concentrations except for the highest percentiles, at which
the observed concentrations were higher than the estimated. For azinphos
methyl and diazinon (Figures III.E.1-4 and -5), the estimated concentrations
were consistent with those observed in the Pudding River, but were
consistently lower than the Zollner creek concentrations.
u
I
4.5E-01
4.0E-01
3.5E-01
3.0E-01
2.5E-01
2.0E-01
1.5E-01
1.0E-01
5.0E-02
O.OE + 00
* Estimated
• Zollner Creek
A Pudding River
20 40 60 80
Percentile
100
120
| Figure III.E.1-2. Comparison of observed and estimated chlorpyrifos
I concentrations in the Northwest Region.
:
I
I.E.1 Page 8
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» Estimated
• Zollner Creek
A Pudding River
40 60 80
Percentile
100
120
I Figure III.E.1-3. Comparison of observed and estimated ethoprop concentrations
§ in the Northwest Region.
Estimated
i Zollner C reek
i Pudding River
40 60 80
Percentile
100
120
Figure III.E.1-4. Comparison of observed and estimated azinphos methyl
concentrations in the Northwest Region.
E stim a ted
Zollner C reek
Pudding R iver
20 40 60 80 100 120
P ercen tile
Figure III.E.1-5. Comparison of observed and estimated diazinon concentrations
in the Northwest Region.
III.E.1 Page 9
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[ ii. Summary of NAWQA Monitoring Data in the Region
| The great majority of the surface water in the Northwest Region drains to
I the Columbia River. The Columbia is a highly managed water body, and
| constitutes an important source of electricity and irrigation water.
I The Willamette Basin (WILL) NAWQA study unit is located in western
| Oregon. This is the high-use, high vulnerability region selected to represent
I the Fruitful Rim, NW through PRZM-EXAMS simulation modeling. Twenty-
| two percent of land in this basin is devoted to agriculture, and another 70% to
I forestry. The cities of Portland, Salem and Eugene are located within this
• i study unit. In 1990, 70% of Oregon's population lived in the Willamette Basin
-«-» j (USGS Circular 1161).
?•——f ~
P* | Surface water is the predominant source of drinking water in the area. The
C ! city of Portland derives its water from the pristine Bull Run Watershed, and is
CO I not even required to filter its water. However, water resources in the
CO f agricultural Willamette Valley are vulnerable to contamination from
CD [ agricultural chemicals. Data from the WILL include some of the highest OP
92 I concentrations in the NAWQA program.
w i
^ [ Four intensive stream-sampling sites were sampled monthly in urban and
I agricultural areas. Another 44 stream stations throughout the study unit were
| sampled once each in 1993 and 1994. Azinphos methyl, ethoprop, diazinon,
1 malathion and chlorpyrifos were the active OPs detected in surface water of
I the WILL.
[ The highest OP concentrations in this study unit were detected in Zollner
I Creek, which drains a basin 99% devoted to agriculture. Forty-three
I pesticides in all were detected at this sampling station. Azinphos methyl was
^ I detected in 32% of samples at this site, with a maximum concentration of
C 1 7.35 ug/l. Ethoprop was detected in 75% of Zollner Creek samples, with a
™ I maximum detection of 1.95 ug/l. Diazinon and chlorpyrifos were detected in
| 72% and 65% of samples, with maximum detections of 1.28 and 0.40 ug/l,
| respectively. The highest concentration of malathion detected in the WILL,
1 0.24 ug/l, was also detected in Zollner Creek.
Zollner Creek is not a direct source of drinking water. However, it
illustrates the possibility of high acute concentrations and OP co-occurrence
possible if sampling is undertaken near use sites. Twenty-six of the samples
taken from the Zollner Creek had detections of 4 OPs, and five samples had
5 OPs detected together. The NAWQA program does not include monitoring
targeted to drinking water intakes downstream from heavy OP use areas.
Zollner Creek data indicates that if such a scenario exists, exposure to
multiple OPs may be possible.
I.E.1 Page 10
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I Ground-water studies in the WILL were designed to assess the quality of
I vulnerable resources. Seventy shallow domestic wells in alluvial aquifers
I were sampled once each, as were 53 monitoring wells in the alluvial aquifer
| located in irrigated and non-irrigated farmland regions. Ten further urban
| wells were installed near Portland, and sampled once each. Terbufos was the
CNI I only OP detected, once at <0.01 ug/l.
O I
| The Central Columbia Plateau (CCPT) NAWQA study unit is located
I almost completely in the arid region of eastern Washington, spilling over into
1 western Idaho. It is an area with extensive dryland agriculture, with irrigation
I from the Columbia Basin Irrigation Project in the west, and intermittent areas
1 of ground-water irrigation. Much of the area has few, if any, natural perennial
| streams. The area is much less prone to surface runoff than the Willamette
| Valley, which was the region for surface-water modeling scenarios for the
1 cumulative assessment.
C/) | Eighty-four percent of drinking-water supply in this region comes from
CO | ground water. However, irrigation has changed the local hydrology over the
0 | last 50 years. In the western portion of the study unit (Quincy-Pasco subunit),
C/5 | water from the Columbia Basin Irrigation Project has caused a rise in the
| water table of 50 to 500 feet. Discharge to surface-water bodies is such that
I NAWQA recommends sampling of irrigation wasteways as a way to monitor
I trends in atrazine and nitrate concentrations in this region's ground water.
CO I Ground-water withdrawals in the North-Central subunit, by contrast, has
I caused up to a 150-foot decline in the water table in some places.
0 | Ground-water studies included monitoring of ground water near irrigated
> | row crops, orchards, and dryland grains. All three studies included both
"•*-* I domestic wells and monitoring wells near fields (generally within 1 00 feet for
_£0 | row crops and orchards, and edge-of-field for grains). Azinphos-methyl,
chlorpyrifos and methyl parathion were all detected in ground water in the
CCPT. Azinphos methyl was detected four times (1%) in the orchard study,
with a maximum concentration of about 0.2 ug/l. Methyl parathion was
detected twice in the same study (max 0.07 ug/l), but orchard uses of methyl
parathion are being phased out (Roberts and Jones, 1996).
CL
In addition to fixed sites throughout the study unit, the CCPT included four
intensive sites sampling areas of potato, potato and corn, orchard,and wheat
culture. This targeted sampling resulted in greater than average
agricultural detection of OPs in surface water. Every OP included as an
analyte was detected in at least one surface-water sample. For instance,
azinphos methyl was detected in 16.4% of agricultural samples, with a
maximum concentration of 0.5 ug/l. Ethoprop was detected in 9.2% of
agricultural samples, with a maximum concentration of 0.22 ug/l. Chlorpyrifos
was detected in 27% of agricultural samples, with a maximum concentration
of 0.12 ug/l. Diazinon, malathion, methyl parathion, phorate and terbufos
I.E.1 Page 11
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were all detected in 6% of samples or fewer, with maximum concentrations of
<0.1 ug/l.
0)
co-
Every OP was also detected in stream samples described as "mixed use."
While the frequency of detection overall was less than in agricultural streams,
the maximum concentrations were higher. For instance, the maximum
concentration of disulfoton in these streams was 3.8 ug/l. The rest of the
OPs were detected at < 1.0 ug/l, but mostly with maximum concentrations of
above 0.1 ug/l.
Therefore, higher frequencies and concentrations of OPs were found by
targeted monitoring in this semi-arid area, just as they were at the Zollner
Creek in the Willamette Valley.
Only 6% of land in the Puget Sound Basin (PUGT) NAWQA study unit is
dedicated to agriculture. Drinking water in this region is drawn about equally
from surface-water and ground-water sources.
No OPs were detected in three ground-water monitoring programs
sampling from the Fraser aquifer in the "Puget Lowlands." The Fraser is a
shallow, unconfined, glacial aquifer which underlies the main agricultural
region in the study unit. Surface-water studies in the PUGT included 4
intensive study sites (2 agricultural, 1 urban, 1 mixed-use) that were sampled
weekly to monthly for a year (two for urban samples). In addition, 13 urban
and residential sites were sampled 2 to 4 times each in response to
detections of diazinon and other urban-use chemicals.
Diazinon was detected in 47% of agricultural surface-water samples , with
a maximum concentration of 0.113 ug/l. Diazinon was detected in 84% of
urban stream samples. Chlorpyrifos was only detected in urban or mixed-use
samples. The only other OPs detected were malathion (1 of 20 detections
from agricultural use, maximum concentration 0.087 ug/l) and ethoprop (3
detections, maximum 0.019 ug/l).
Table III.E.1-4. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Northwest Region
* Land Use ,
' K, S, «"
• Value
Chlorpyrifos
diazinon
disulfoton
ethopro
; p
malathion
', „
azinphos
methyl
. methyl
parathion
phorate
terbufos
, - , , i • Concentatipn (ug/L)
Willamette River Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.401
0.060
0.023
0.014
0.008
0.006
0.004
39.3%
1.280
0.192
0.061
0.029
0.013
0.009
0.003
49.9%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
1.950
0.558
0.099
0.033
0.009
0.005
0.003
28.7%
0.237
0.029
0.027
0.020
0.005
0.005
0.005
4.5%
7.350
0.914
0.081
0.050
0.001
0.001
0.001
9.7%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
Agricultural
Maximum
0.401
1.280
0.021
1.950
0.237
7.350
0.006
0.011
0.017
I.E.1 Page 12
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' •'•^•'Ve^'t
99th
95th
90th
80th
75th
50th
Frequency
Ag: Zollner
Creek
only
Maximum
99th
95th
90th
80th
75th
50th
Frequency
- fn-*'&ft.
0.099
0.032
0.018
0.011
0.010
0.004
48.0%
*«;,. >-.
0.722
0.136
0.045
0.017
0.013
0.005
59.2%
i > ,.- ».^%
disulfoton*
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.401
0.147
0.036
0.029
0.017
0.014
0.006
64.8%
1.280
1.167
0.165
0.119
0.037
0.025
0.010
71.6%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
ethoRrq,
Bifepnt;
1.011
0.269
0.115
0.046
0.031
0.004
52.3%
«****
Iwtt
^P$?P?w**^
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
ymmyMffiliL
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
Ag Besides
Zollner
Creek
Forest/
Reference
Urban
Maximum
99th
95th
90th
• 80th
75th
50th
Frequency
0.032
0.023
0.011
0.009
0.005
0.004
0.004
25.0%
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.005
0.005
0.005
0.005
0.004
0.004
0.004
0.0%
0.046
0.046
0.040
0.029
0.020
0.016
0.006
60.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.014
0.013
0.007
0.006
0.005
0.005
0.004
38.3%
0.170
0.082
0.010
0.009
0.006
0.005
0.002
42.2%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.054
0.043
0.013
0.006
0.003
0.003
0.003
20.6%
0.005
0.005
0.005
0.005
0.002
0.002
0.002
0.0%
0.112
0.105
0.067
0.057
0.033
0.031
0.023
97.5%
0.031
0.023
0.009
0.006
0.005
0.005
0.002
43.5%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.005
0.005
0.005
0.005
0.003
0.003
0.003
0.0%
0.013
0.012
0.007
0.005
0.005
0.005
0.005
6.3%
0.099
0.077
0.001
0.001
0.001
0.001
0.001
4.9%
0.027
0.027
0.027
0.027
0.005
0.005
0.005
0.0%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.009
0.009
0.007
0.005
0.005
0.003
0.003
13.2%
0.052
0.042
0.027
0.027
0.019
0.006
0.005
10.0%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.029
0.024
0.013
0.005
0.003
0.003
0.003
14.8%
0.027
0.027
0.027
0.005
0.005
0.005
0.005
2.6%
0.05
0.05
0.05
0.05
0.001
0.001
0.001
0.0%
0.171
0.126
0.050
0.050
0.001
0.001
0.001
2.6%
0.050
0.050
0.050
0.001
0.001
0.001
0.001
0.9%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
III.E.1 Page 13
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Landilse
' •/ *>"?
Value ,.
chlo'rpyrifos
diazinon
disulfoton
ethopro
P "
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
;,-,, .'. •»•*•; «•• Concentation (ug/L)
Upper Snake River
All
locations
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.190
0.011
0.004
0.004
0.004
0.004
0.004
3.0%
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.190
0.072
0.004
0.004
0.004
0.004
0.004
4.2%
0.095
0.009
0.002
0.002
0.002
0.002
0.002
3.4%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.004
0.004
0.003
0.003
0.003
0.003
0.003
1.3%
0.020
0.005
0.005
0.005
0.005
0.005
0.005
0.4%
0.095
0.041
0.002
0.002
0.002
0.002
0.002
4.2%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.020
0.005
0.005
0.005
0.005
0.005
0.005
0.6%
0.031
0.001
0.001
0.001
0.001
0.001
0.001
0.9%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.012
0.002
0.002
0.002
0.002
0.002
0.002
0.4%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.031
0.003
0.001
0.001
0.001
0.001
0.001
1.2%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.012
0.002
0.002
0.002
0.002
0.002
0.002
0.6%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
Forest/
Reference
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.003
0.003
0.003 '
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
1.6%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.004
0.004
0.003
0.003
0.003
0.003
0.003
4.9%
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.0%
0.001
0.001
0.001
0.001
.0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
Central Columbia Plateau
All
locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
.0.120
0.088
0.022
0.009
0.004
0.004
0.004
18.9%
0.270
0.059
0.010
0.005
0.002
0.002
0.002
7.7%
3.810
0.024
0.017
0.017
0.017
0.017
0.017
2.1%
0.220
0.059
0.005
0.004
0.003
0.003
0.003
8.3%
0.130
0.027
0.012
0.005
0.005
0.005 '
0.005
3.5%
0.500
0.128
0.055
0.040
0.010
0.001
0.001
9.9%
0.300
0.091
0.006
0.006
0.006
0.006
0.006
1.3%
0.062
0.011
0.002
0.002
0.002
0.002
0.002
0.5%
0.096
0.017
0.013
0.013
0.013
0.013
0.013
0.5%
I.E.1 Page 14
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CM
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X.
Land Use
Agricultural
.Value-V.
, vJ$
Maximum
99th
95th
90th
80th
75th
50th
Frequency
*•* V*
chlprpyrjfbs
diazinon
*jf ^ *%
* * >K
disulfoton
-k ^ *•- f x
0.120
0.116
0.057
0.016
0.006
0.005
0.004
26.7%
0.100
0.052
0.005
0.002
0.002
0.002
0.002
6.2%
0.035
0.022
0.017
0.017
0.017
0.017
0.017
3.1%
ethopro1
^ p.'.H^
,% * V- *; *
malathton
* 4^ ^r ^ ^
a?i.l}Ph,(&
\rr\ethyft*
0.220
0.107
0.005
0.004
0.003
0.003
0.003
9.2%
0.093
0.027
0.011
0.005
0.005
0.005
0.005
5.6%
0.500
0.134
0.072
0.050
0.013
0.001
0.001
16.4%
ifn«$iy(^
para truant
iPi?illF^***i
0.094
0.007
0.006
0.006
0.006
0.006
0.006
2.1%
".Wk-fi!
0.045
0.011
0.002
0.002
0,002
0.002
0.002
0.5%
KlftHM!*
tfiSHJBisS
0.087
0.017
0.013
0.013
0.013
0.013
0.013
0.5%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.108
0.043
0.010
0.005
0.004
0.004
0.004
11.4%
0.116
0.051
0.010
0.005
0.002
0.002
0.002
11.4%
3.810
0.029
0.021
0.017
0.017
0.017
0.017
1.1%
0.115
0.033
0.005
0.005
0.003
0.003
0.003
7.4%
0.130
0.027
0.023
0.005
0.005
0.005
0.005
1.1%
0.257
0.078
0.050
0.030
0.001
0.001
0.001
2.8%
0.300
0.158
0.006
0.006
0.006
0.006
0.006
0.6%
0.062
0.012
0.01 1
0.002
0.002
0.002
0.002
0.6%
0.096
0.017
0.017
0.013
0.013
0.013
0.013
0.6%
Puget Sound Basin
All
locations
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.075
0.029
0.005
0.005
0.004
0.004
0.004
2.4%
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
0.501
0.411
0.155
0.107
0.050
0.031
0.005
50.7%
0.113
0.102
0.066
0.053
0.012
0.006
0.002
47.1%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
Urban
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Mixed
Maximum
99th
0.075
0.033
0.015
0.006
0.004
0.004
0.004
5.3%
0.501
0.486
0.285
0.171
0.108
0.093
0.031
84.2%
0.021
0.021
0.018
0.017
0.017
0.017
0.017
0.0%
0.019
0.006
0.005
0.003
0.003
0.003
0.003
1.4%
0.013
0.011
0.004
0.003
0.003
0.003
0.003
5.9%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%
0.087
0.073
0.027
0.027
0.005
0.005
0.005
9.4%
0.050
0.050
0.050
0.001
0.001
0.001
0.001
0.0%
0.025
0.020
0.010
0.005
0.005
0.005
0.005
2.9%
0.087
0.078
0.038
0.027
0.013
0.005
0.005
17.9%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.050
0.050
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.005
0.005
0.083
0.060
0.021
0.021
0.019
0.008
0.027
0.027
0.050
0.050
0.006
0.006
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
I.E.1 Page 15
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Land JJse '
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I.E.1 Page 16
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c. Region C: Arid/Semiarid West
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Estimated concentrations for individual OP pesticides in the region were in
the sub-part per billion range (Table III.E.1-5). Several OPs - Chlorpyrifos,
diazinon, disulfoton, methidathion, and phorate- had estimated maximum
concentrations of 0.1 to 0.3 ppb. At the 99th percentile level, only diazinon
had an estimated concentration greater than 0.1 ppb. More detailed
discussion and analysis of the OP load in drinking water sources can be
found in section II.C.
Table III.E.1-5. Estimated percentile concentrations of individual OP pesticides
and of the cumulative OP distribution in the Arid/Semiarid West Region.
v ,• • w •' I
H' i*,1' «i'X
Chemical "f '«-*"'."•
Acephate
Azinphos
Methyl .
Chlorpyrifos
Diazinon
DDVP
Dimethoate
Disulfoton
Malathion
Methamidophos
Methyl
Parathion
Methidathion
Naled
ODM
Phorate
Phosmet
%vfi?t$$£. '•£ X '™*&r\ 'fjf-ViJiStlaP
Crop/die^
Legume vegetables, tomato
Apples, pears; nuts (almonds,
walnuts)
Nuts; fruit trees; alfalfa, sugarbeets;
corn; grapes; tomato; asparagus
nuts; fruit trees; grapes; brassicas;
tomato; melons
Naled degradate
Fruit trees; alfalfa; corn; grapes;
legumes; tomatoes; brassicas;
melons
Asparagus
Alfalfa; corn; grapes, legumes;
tomatoes; asparagus
Acephate degradate; tomato;
sugarbeet; legume; brassicas
Alfalfa
Nut trees; fruit trees
Nut trees; fruit trees; sugarbeets;
grapes; legumes
Sugarbeet; brassicas; melons
Sugarbeet, corn
nut trees; fruit trees; alfalfa
OP cumulative concentration in methamidophos
equivalents
Goncentration
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disulfoton were detected in the NAWQA study. Approximately 99 percent of
the estimated concentrations for phorate fell below the USGS analytical limit
of detection (LOD). The estimated maximum concentration for disulfoton was
7 times greater than the LOD; 99th and 95th percentile estimates were roughly
2 times greater than the LOD.
Numerous co-occurrences of chlorpyrifos and diazinon were observed in
many of the agricultural sites. For chlorpyrifos (Figure III.E.1-6) and diazinon
(Figure III.E.1-7) concentrations in a representative water body such as
Orestimba Creek, the estimated concentrations were consistent with the
lower percentiles of monitoring data in Orestimba creek, but were lower at the
highest percentiles,
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
'
Estimated
Orestimba C reek
20
40
60
Percentile
80
100
120
Figure III.E.1-6. Comparison of observed and estimated chlorpyrifos
concentrations in the Arid/Semiarid West Region.
a
a.
o
O
20 40 60 80 100 120
• Estimated
A Orestimba Creek
Figure III.E.1-7. Comparison of observed and estimated diazinon concentrations
in the Arid/Semiarid West Region.
I.E.1 Page 18
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ii. Summary of NAWQA Monitoring Data in the Region
The Sacramento River Basin (SACR) NAWQA study site includes the
Sacramento Valley in the West region. The Sacramento River is the largest
river in the State of California, and is a highly managed water body which
CXI meets the needs of the more than one million people in the Sacramento area.
O The USGS indicates that while the concentrations of OP insecticides in
agricultural and urban streams in this region "sometimes exceed amounts
that are toxic to zooplankton in laboratory tests, the toxicity is greatly reduced
or eliminated when concentrations of these pesticides are diluted by the
Sacramento River" (USGS Water Resources Circular 1215).
Surface-water monitoring included 3 intensive sampling sites, including
the Colusa Basin Drain, which in the late 1980s had elevated concentrations
of methyl parathion and malathion detected. Since that time, a program to
reduce spray drift and increase paddy-water holding time has reduced
(/) detected concentrations dramatically. A description of this program is
CO included in the State Monitoring Appendix. An urban intensive study site was
CD also sampled.
CO
~z In the SACR study, chlorpyrifos, diazinon, malathion and azinphos-methyl
were detected in surface water. Diazinon was detected in 71% of agricultural
samples, and 35% of mixed land-use samples, with a maximum
CO concentration of slightly over 0.1 ug/l. Chlorpyrifos was detected in 29% of
agiricultural samples, and a single mixed land-use sample, with a maximum
concentration detected of about 0.05 ug/l. Malathion was detected in 53% of
0 urban samples and 33% of agricultural samples, with a maximum detection of
> nearly 1 ug/l.
The San Joaquin-Tulare Basins (SANJ) NAWQA study site includes the
13 southern Central Valley of California. Surface water accounts for more overall
C. water use than ground water, but ground water is the predominant source of
drinking water in this region (USGS Water Resources Circular 1159).
Irrigation accounts for the greatest amount of water use, and is also the
greatest source of aquifer recharge, which can lead to contamination of
n ground water with agricultural chemicals.
Ground-water monitoring in the SANJ included single samples from 30
domestic wells around the eastern portion of the valley. Monitoring also
0 included in single samples from 20 domestic wells and 10 monitoring wells
CO each in almond, vineyard and row crop land-use ground-water studies. More
than 50% of the monitoring wells in each of these studies was within a
0 quarter-mile of cropped fields. Chlorpyrifos, malathion and diazinon were
detected in one, two and three ground water samples, respectively. One
detection of malathion at 0.1 ug/l was the highest OP concentration detected
in ground water.
I.E.1 Page 19
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v—
The SANJ report specifically mentions that "high concentrations of
organophosphate insecticides, resulting from application to some orchards
during the winter, are of particular concern" (USGS Water Resources Circular
1159). Surface-water monitoring included biweekly to monthly sampling at
intensive agricultural, rangeland and urban sites in 1993. Another 23 sites
were sampled once at low flow in urban and agricultural areas.
Diazinon was detected in 71 % of samples taken, with a maximum
concentration of 3.8 ug/l. Chlorpyrifos was detected in 52 % of samples, with
a maximum concentration of about 0.5 ug/l. Azinphos methyl was also
extensively (12%) detected, with a maximum concentration of about 1.0 ug/l.
Malathion was detected in 8% of samples, with a maximum concentration
between 0.5 and 1.0 ug/l. Ethoprop, disulfoton, methyl parathion and terbufos
were detected in fewer than 1% of samples analyzed.
The maximum concentrations of Chlorpyrifos were detected in samples
taken around the winter application season.
C0
The USGS San Joaquin River Basin study included a study designed to
determine sampling frequency needed to characterize the occurrence and
distribution of pesticides in surface water in a semiarid agricultural region
such as the SJRB. Results indicated that sampling three times per week is
more likely to detect higher concentrations than once per week as indicated
by the larger variance about the median for the more frequent sampling.
Sampling once per week is sufficient if only the median concentration is
important.
The Central Arizona Basins (CAZB) NAWQA study unit is located in
southern and central Arizona. The dominant source of drinking water in
TO 1 central Arizona are deep basin aquifers, some of which may have been
•3 recharged thousands of years ago. At the very least, 55% of wells tested in
the Central Arizona Basins NAWQA study area (CAZB) were recharged
before 1953 (USGS Water Resources Circular 1213).
Alluvial deposits in the vicinity of major streams in Arizona range in
thickness up to about 300 feet, and where locally saturated serve as aquifers.
Chlorpyrifos was detected in a single sample from a shallow monitoring well
in the CAZB study unit, but no OP was detected in samples from wells
installed in the deeper aquifers. Although a single sampling of a well network
is not definitive in determining the likelihood of pesticide contamination, the
depth of the aquifers, combined with the very low rainfall for the region, result
in very slow recharge rates which may delay contamination by OP residues
for a long time.
Surface-water monitoring in this region included two intensive sampling
sites from agricultural streams, and three other fixed sites which were
sampled quarterly. Diazinon was detected in 97% of samples, and
III.E.1 Page 20
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chlorpyrifos in 94%, all below 0.5 ug/l. malathion was detected in 26% of
samples at similar concentrations. Disulfoton was detected once at nearly 1
ug/l. Azinphos methyl, methyl parathion and phorate are also reported to
have been detected in surface water.
However, while these mixed agricultural/urban streams may be effected
ecologically by this contamination, they are not used as drinking water
sources. The two streams (Buckeye Canal and Hassayampa River) are
typical of most in the region, in that flow is maintained through addition of
treated wastewater effluent and irrigation return water.
Table III.E.1-6. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Arid/Semiarid West Region
Land Use>(1,
**SWt%-**l W^JH^41WSW*MW<¥SW<-;'llfflBDilO§s,,
San Joaquin-Tulare Basins
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.340
0.182
0.053
0.030
0.015
0.012
0.005
61.3%
0.340
0.258
0.085
0.042
0.025
0.019
0.008
66.9%
9.050
1.148
0.340
0.170
0.080
0.055
0.016
83.9%
0.060
<0.021
<0.021
<0.021
O.021
<0.017
<0.017
0.1%
0.029
0.011
<0.005
<0.005
<0.005
<0.003
O.003
1.2%
0.390
0.068
0.027
0.027
<0.027
O.015
<0.005
13.8%
1.000
0.210
0.056
0.050
<0.050
<0.050
<0.001
10.5%
pacatnKin»
0.090
0.021
<0.006
<0.006
<0.006
<0.006
<0.006
0.3%
<0.06
<0.018
<0.011
<0.011
<0.011
<0.003
<0.002
0.0%
9.050
2.180
0.360
0.160
0.082
0.066
0.020
85.3%
<0.050
<0.021
<0.021
<0.021
<0.017
<0.017
<0.017
0.0%
0.029
0.018
<0.005
<0.005
<0.003
<0.003
<0.003
2.9%
0.390
0.126
0.027
0.027
<0.009
<0.005
<0.005
12.6%
1.000
0.276
0.099
0.060
0.050
0.045
<0.001
24.6%
0.090
0.056
<0.006
<0.006
<0.006
<0.006
<0.006
0.6%
<0.06
<0.047
<0.011
<0.011
<0.003
<0.002
<0.002
0.0%
0.100
0.018
<0.017
<0.017
<0.017
<0.013
<0.013
0.3%
0.100
0.020
<0.017
<0.017
<0.013
<0.013
<0.013
0.3%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.260
0.069
0.030
0.017
0.011
0.009
0.005
57.4%
2.900
0.764
0.230
0.150
0.067
0.047
0.013
82.9%
<0.021
<0.021
<0.021
<0.021
<0.021
<0.021
<0.017
0.0%
0.010
<0.005
<0.005
<0.005
<0.005
<0.005
<0.003
0.3%
0.160
0.037
0.027
0.027
<0.027
<0.019
<0.005
12.2%
0.400
0.059
<0.050
<0.050
<0.050
<0.050
<0.001
3.2%
0.018
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
0.2%
<0.06
<0.011
<0.011
<0.011
<0.011
<0.011
<0.002
0.0%
0.024
<0.017
<0.017
<0.017
<0.017
<0.017
<0.017
0.3%
Sacramento R. Basin
All
Locations
Maximum
99th
95th
90th
80th
0.045
0.033
0.019
0.015
0.007
1.380
0.780
0.425
0.296
0.177
<0.021
<0.021
<0.021
<0.021
<0.017
<0.005
<0.005
<0.005
<0.005
<0.003
0.634
0.139
0.054
0.028
0.027
0.500
0.237
<0.050
<0.050
<0.017
<0.006
<0.006
<0.006
<0.006
<0.006
<0.011
<0.011
<0.011
<0.011
<0.002
<0.017
<0.017
<0.017
<0.017
<0.013
I.E.1 Page 21
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Land Use
Agricultural
Value
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
chlorpyrifos
0.005
<0.004
26.5%
0.016
0.016
0.016
0.014
0.008
0.005
<0.004
26.5%
diazinon
0.089
0.009
67.7%
0.106
0.103
0.082
0.063
0.034
0.030
0.008
76.5%
disulfoton
Concents
<0.017
O.017
0.0%
<0.021
<0.021
<0.021
<0.021
<0.017
<0.017
<0.017
0.0%
ethoprop
lion (ug/L)
<0.003
<0.003
0.0%
<0.005
<0.005
<0.005
<0.005
<0.003
<0.003
<0.003
0.0%
Urban
Mixed
Maximum
99th
95th
90th
. 80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.045
0.041
0.032
0.026
0.020
0.017
0.009
78.4%
. 0.006
0.005
<0.005
<0.005
<0.005
<0.004
<0.004
3.6%
1.380
1.186
0.751
0.563
0.434
0.410
0.275
100.0%
0.154
0.071
0.049
0.035
0.015
0.011
0.003
50.0%
<0.021
<0.021
<0.021
<0.017
<0.017
<0.017
O.017
0.0%
<0.021
<0.021
<0.021
<0.021.
<0.019
<0.017
<0.017
0.0%
<0.005
<0.005
<0.005
<0.003
<0.003
<0.003
<0.003
0.0%
<0.005
<0.005
<0.005
<0.005
<0.004
<0.003
<0.003
0.0%
malathion
0.027
<0.005
25.2%
0.054
0.053
0.036
0.027
0.027
0.023
<0.005
29.4%
azinphos
methyl
<0.001
<0.001
1.3%
<0.050
<0.050
<0.050
<0.050
<0.001
<0.001
<0.001
0.0%
methyl
parathion
<0.006
<0.006
0.0%
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
0.0%
phorate
<0.002
<0.002
0.0%
<0.011
<0.011
<0.011
<0.011
<0.002
<0.002
<0.002
0.0%
terbufos
<0.013
<0.013
0.0%
<0.017
<0.017
<0.017
<0.017
<0.013
<0.013
<0.013
0.0%
0.634
0.458
0.137
0.083
0.055
0.048
0.015
56.8%
0.027
0.027
0.027
<0.027
<0.024
<0.01
<0.005
9.5%
0.500
0.464
0.159
<0.062
<0.024
<0.001
<0.001
2.7%
<0.050
<0.050
<0.050
<0.050
<0.028
<0.001
<0.001
1.2%
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
0.0%
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
0.0%
<0.011
<0.011
<0.011
<0.002
<0.002
<0.002
<0.002
0.0%
<0.011
<0.011
<0.011
O.011
<0.006
<0.002
<0.002
0.0%
<0.017
<0.017
<0.017
<0.013
<0.013
<0.013
<0.013
0.0%
<0.017
<0.017
<0.017
<0.017
<0.015
<0.013
<0.013
0.0%
Central Arizona Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.154
0.152
0.067
0.047
0.029
0.025
0.016
82.7%
0.207
0.132
0.111
0.102
0.082
0.077
0.056
82.7%
0.826
0.775
0.021
O.018
<0.017
<0.017
<0.017
4.1%
<0.005
<0.005
<0.005
<0.003
<0.003
<0.003
<0.003
0.0%
0.270
0.256
0.243
0.118
0.027
0.015
<0.005
24.5%
0.300
0.242
0.091
0.050
0.006
<0.001
<0.001
1.0%
0.521
0.503
0.256
0.036
<0.006
<0.006
<0.006
9.2%
0.080
0.013
0.011
<0.010
<0.002
<0.002
<0.002
5.1%
<0.017
<0.017
<0.017
<0.013
<0.013
<0.013
<0.013
0.0%
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
0.154
0.153
0.122
0.067
0.047
0.038
0.020
0.207
0.170
0.083
0.079
0.070
0.058
0.037
0.826
0.801
. 0.747
O.017
<0.017
<0.017
O.017
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
0.270
0.263
0.252
0.160
0.017
0.013
<0.005
0.300
0.204
<0.074
<0.032
<0.001
<0.001
<0.001
0.521
0.512.
0.453
0.259
0.036
<0.006
<0.006
0.080
0.047
0.011
0.004
<0.002
<0.002
<0.002
<0.013
<0.013
<0.013
<0.013
<0.013
<0.013
<0.013
I.E.1 Page 22
-------
CM
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'Larjd Use
Frequency
t»\ •*~<%v|j>Alv««».
93.8%
^n^iv^waMfc™**
89.6%
8.3%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.043
0.039
0.032
0.029
0.025
0.024
0.017
94.6%
0.123
0.119
0.112
0.110
0.103
0.100
0.074
100.0%
O.017
<0.017
<0.017
O.017
<0.017
<0.017
<0.017
0.0%
0.0%
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
0.0%
29.2%
0.243
0.213
0.131
0.119
0.018
0.006
<0.005
27.0%
2.1%
18.8%
10.4%
0.0%
<0.24
<0.226
<0.12
<0.048
<0.001
<0.001
<0.001
0.0%
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
<0.006
0.0%
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
0.0%
<0.013
<0.013
<0.013
<0.013
<0.013
<0.013
<0.013
0.0%
C
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I.E.1 Page 23
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CM
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d. Region D: Northeast/ North Central
Terbufos, which accounted for three-fourths of total OP use in the
assessment area, dominated the cumulative load for the region(Table III.E.1-
7). More detailed discussion and analysis of the OP load in drinking water
sources can be found in section II.D.
Table III.E.1-7. Predicted percentile concentrations of individual OP pesticides
and of the cumulative OP distribution in the Northeast/North Central Region.
Chemical
AzinphosMethyl
Chlorpyrifos
Dimethoate
Phorate
Terbufos
. Crop/Use
Potato
Sugarbeet,
Wheat
Potato
Sugar beet
Suaar beet
OP Cumulative Concentrations in
Methamidoohos equivalents
Concentrations in ug/L (ppb)
Max
4.9e-02
4.7e-02
3.8e-02
5.6e-02
1.9e+00
4.96+00
99th ,
2.2e-02
2.6e-02
7.46-03
2.5e-03
5.9e-01
1.56+00
95th
1 .2e-02
1.56-02
2.8e-03
7.9e-05
1.96-01
4.86-01
90th
7.2e-03
1.1e-02
1.16-03
2.86-06
7.96-02
2.06-01
80th
4.2e-03
6.2e-03
2.26-04
2.9e-09
2.0e-02
5.5e-02
75th
3.16-03
4.7e-03
1.2e-04
8.2e-11
1.1e-02
3.0e-02
50th
7.06-04
1 ,4e-03
1.66-05
3.86-13
1.76-03
5.5e-03
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a:
i. Comparison of Monitoring Data versus Model Estimates
A comparison of estimated concentrations for individual OP pesticides
with NAWQA monitoring indicates that the predicted maximum and 99th
percentile concentrations of chlorpyrifos, azinphos methyl, and phorate were
similar to monitoring detections in the Red River Basin. The highest reported
detection for terbufos was equivalent to the estimated 90th percentile
concentration. However, the model estimates include the more persistent and
mobile sulfone and sulfoxide residues, while the monitoring only represents
the parent concentrations.
In the 28 agricultural sampling sites, only the Snake River (combined
locations), Turtle River, and the Tamarac River had any detections of OP's.
Neither terbufos nor phorate were detected. However, it is important to note
that parent terbufos and phorate rapidly form sulfoxide and sulfone
metabolites, and the analytical method may be for parent only. Azinphos
methyl, was the only OP detected from a site other than the Snake River and
the Turtle River. Estimated and observed concentrations of cchlorpyrifos
(Figure III.E.1-8) were consistent throughout all percentiles.
I.E.1 Page 24
-------
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• • . • Ttmrmr . . ~
20 40 60 80 100 1:
Percentile
• Estimated
A Turtle River
• Snake River
!0
] Figure III.E.1-8. Comparison of observed and estimated chlopryrifos
| concentrations in the Northeast/North Central Region.
In the preliminary assessment, the estimated peak and upper percentile
concentrations of chlorpyrifos in the Heartland region (central Illinois) are
roughly equivalent to the concentrations detected in the agricultural
watersheds of the Lower Illinois River Basin (LIRE) while the maximum
estimated concentration of total terbufos residues (parent plus toxic sulfoxide
and sulfone transformation products) was an order of magnitude greater than
the maximum detection reported for the parent terbufos (without the
transformation products) in the LIRE. The maximum detection of terbufos in
NAWQA fell between the 90th and 95th percentile of estimated concentrations
to total terbufos residues. Between 80 and 90 percent of the estimated
terbufos concentrations were below the analytical level of detection.
ii. Summary of NAWQA Monitoring Data in the Region
Stream-water sampling in the Red River of the North Basin (REDN)
NAWQA study unit included a study of intensive agriculture areas, in which 5
stations were sampled at least monthly and during runoff events between
1993 and 1995. Chlorpyrifos is the OP most often detected in the REDN
study unit. Chlorpyrifos was detected in 14 samples, but only five of these
were samples from.streams identified as "agricultural" (maximum
concentration 0.031 ug/l). The nine other chlorpyrifos detections, and the
three reported diazinon detections, were from "mixed land-use" (MLU)
streams, and may not represent agricultural contamination. Malathion,
disulfoton, ethoprop, methyl parathion, phorate, terbufos, and azinphos
methyl were also detected in surface water samples.
Malathion is the only OP which was detected in ground water. This single
detection was at a concentration below 0.01 ug/l. this sample was taken from
the unconsolidated glacial aquifer. No pesticides of any kind (including
herbicides) were detected in five samples from buried glacial aquifers or six
samples from older bedrock aquifers (Cowdery, 1998).
I.E.1 Page 25
-------
Table III.E.1-8. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Northern Great Plains Portion of
Northeast/North Central Region.
the
Land Use
Value
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
Concentation (ug/L)
Red River Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.087
0.020
<0.004
<0.004
<0.004
<0.004
<0.004
4.5%
Agriculture
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.031
0.018
<0.004
<0.004
<0.004
<0.004
<0.004
2.8%
0.104
0.004
<0.002
<0.002
<0.002
<0.002
<0.002
1.0%
0.080
<0.017
<0.017
<0.017
0.017
0.017
O.017
0.3%
<0.005
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
0.0%
O.020
O.017
O.017
O.017
O.017
O.017
O.017
0.0%
0.087
0.028
<0.004
<0.004
<0.004
<0.004
<0.004
7.2%
0.104
0.009
<0.002
<0.002
<0.002
<0.002
<0.002
2.4%
0.080
O.017
O.017
0.017
O.017
O.017
0.017
0.8%
0.099
0.004
O.003
O.003
O.003
0.003
0.003
0.6%
0.004
O.004
O.003
O.003
O.003
O.003
0.003
0.6%
0.290
0.020
O.005
O.005
O.005
O.005
O.005
3.5%
0.117
0.001
O.001
O.001
O.001
0.001
O.001
0.6%
0.290
0.016
O.005
0.005
O.005
O.005
O.005
1.7%
0.01
O.003
0.001
O.001
O.001
O.001
0.001
0.6%
0.0992
O.003
O.003
O.003
O.003
O.003
0.003
0.8%
0.107
0.036
0.009
O.005
0.005
O.005
O.005
6.3%
0.117
O.001
O.001
0.001
O.001
O.001
O.001
0.8%
0.114
0.010
0.006
O.006
O.006
O.006
O.006
1.0%
O.010
O.006
O.006
0.006
O.006
O.006
O.006
0.0%
0.078
O.002
O.002
O.002
O.002
O.002
O.002
0.3%
'
O.020
O.002
O.002
0.002
O.002
O.002
O.002
0.0%
0.080
O.013
O.013
O.013
O.013
O.013
O.013
0.3%
O.013
O.013
O.013
O.013
O.013
O.013
O.013
0.0%
0.114
0.068
O.006
O.006
0.006
O.006
O.006
2.4%
0.078
O.012
O.002
O.002
0.002
O.002
O.002
0.8%
0.080
0.013
O.013
O.013
0.013
O.013
O.013
0.8%
Upper Mississippi River Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.060
0.007
<0.004
<0.004
<0.004
<0.004
<0.004
1.7%
0.190
0.102
0.053
0.022
0.007
<0.004
O.002
24.3%
O.021
O.021
O.017
O.017
O.017
O.017
O.017
0.0%
0.020
O.005
O.003
0.003
O.003
O.003
O.003
0.6%
0.0543
. 0.042
O.015
O.005
O.005
O.005
O.005
3.2%
0.0148
O.137
O.001
O.001
O.001
O.001
O.001
0.3%
O.006
O.006
0.006
O.006
O.006
0.006
O.006
0.0%
O.011
O.011
0.002
O.002
O.002
0.002
O.002
0.0%
O.017
O.017
0.013
O.013
O.013
0.013
O.013
0.0%
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
<0.060
<0.020
<0.004
<0.004
<0.004
<0.004
<0.004
0.0%
<0.005
<0.005
<0.002
<0.002
<0.002
<0.002
<0.002
0.0%
O.021
O.021
O.017
O.017
O.017
O.017
O.017
0.0%
0.020
0.009
O.004
O.003
0.003
O.003
O.003
2.7%
0.0061
0.150
O.027
O.005
O.005
O.005
O.005
1.4%
0.050
O.050
O.001
O.001
O.001
O.001
0.001
0.0%
0.006
O.006
O.006
O.006
O.006
O.006
0.006
0.0%
O.011
O.011
O.002
O.002
O.002
O.002
O.002
0.0%
0.017
O.017
O.013
O.013
O.013
O.013
0.013
0.0%
CO
I.E.1 Page 26
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CM
O
Land Use
Urban
Value
Maximum
99th
95th •
90th
80th
75th
50th
Frequency
Mixed
Maximum
99th
95th
90th
80th .
75th
50th
Frequency
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
Concentation (ug/L)
0.064
0.040
0.021
0.015
0.008
0.005
<0.004
32.6%
0.300
0.232
0.113
0.060
0.028
0.020
0.004
59.1%
<0.021
<0.021
<0.017
<0.017
<0.017
<0.017
<0.017
0.0%
<0.005
<0.005
<0.003
<0.003
<0.003
<0.003
<0.003
0.0%
0.078
0.027
0.020
0.010
<0.005
<0.005
0.005
11.4%
0.039
0.039
0.007
O.001
0.001
0.001
O.001
2.3%
0.006
0.005
<0.004
<0.004
<0.004
<0.004
<0.004
2.0%
0.009
0.008
0.006
0.004
<0.002
<0.002
0.002
13.2%
<0.021
<0.021
<0.017
<0.017
<0.017
<0.017
<0.017
0.0%
<0.005
<0.005
<0.003
<0.003
<0.003
<0.003
<0.003
0.0%
0.0051
O.027
O.005
0.005
O.005
O.005
O.005
0.7%
0.400
0.200
O.040
O.001
O.001
O.001
0.001
0.0%
O.006
O.006
O.006
0.006
O.006
O.006
O.006
0.0%
O.011
O.011
O.002
0.002
O.002
O.002
0.002
0.0%
0.033
0.018
0.013
0.013
O.013
O.013
0.013
0.8%
0.006
O.006
O.006
0.006
O.006
O.006
O.006
0.0%
O.011
O.011
O.002
0.002
O.002
O.002
O.002
0.0%
0.017
O.017
O.013
0.013
O.013
O.013
O.013
0.0%
C
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In the corn-soybean dominated Lower Ilinois River Basin (LIRB)
unit, chlorpyrifos and diazinon were the OPs most often detected in
surface water, with peak concentrations detected in July and August.
Diazinon was detected in 30% of samples overall (75 detections), but in
<5% of agricultural streams (8 detections), with a maximum agricultural
concentration of 0.071 ug/l. By contrast, 29 of the 37 detections of
chlorpyrifos were in agricultural streams (18% of samples from agricultural
areas), with a maximum concentration of 0.30 ug/l. Malathion (four
detections, maximum 0.027 ug/l), methyl parathion (1 detection, 0.211
ug/l), and terbufos (3 detections, max 0.03 ug/l) were also detected in
surface water. All but one detection of malathion were in streams draining
agricultural areas.
Only one detection of diazinon (.0.01 ug/l) was reported for all OPs in
ground water. This detection occurred in one of 60 samples taken from
domestic and public supply wells in "major aquifers" in the study unit. No
OPs were detected in a land-use study in which "very shallow monitoring
wells" were sampled in areas of corn and soybean production. The ground
water that was sampled from the 57 wells was generally less than 10
years old.
The White River Basin (WHIT) study unit is located in central and
southern Indiana. Agriculture accounts for 70% of land use in the study
unit, with corn and soy as the predominant crops. As in the LIRB, atrazine
and metolachlorwere detected in all samples. Sampling took place
between 1992 and 1996.
Diazinon, chlorpyrifos and malathion were the OPs most extensively
detected in surface water. Diazinon was extensively (25%) detected in
I.E.1 Page 27
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streams draining agricultural areas, with a maximum detection of 0.41
ug/l. When urban and mixed land-use samples are included, however,
diazinon was detected at even greater frequency and concentration
(54.4%, max 1.1 ug/l in 801 urban stream samples). The same was true
for chlorpyrifos (agricultural max 0.12 ug/l) and malathion (overall max
0.67 ug/l), which were detected at half the frequency in surface water
draining agricultural areas alone than in the whole data set.
Azinphos methyl (8 detections), methyl parathion, ethoprop, terbufos
and disulfoton (1 detection) were the other active OPs detected in surface
water, in descending order of frequency. Of these, only ethoprop had a
detection above 0.1 ug/l (one sample at 0.14 ug/l). Terbufos, the OP with
the highest RPF value, was detected at concentrations of 0.013 and 0.016
ug/l.
The Eastern Iowa (EIWA) study unit comprises most of eastern Iowa,
and a very small portion of southern Minnesota. Agriculture accounts for
90% of land use in the study unit.
Chlorpyrifos (urban and agricultural) and malathion (1 urban well
sample) were detected in shallow alluvial aquifer. They were not.detected
in the deeper carbonate aquifer. Chlorpyrifos was detected in 16 and 10
percent of shallow ground-water wells in agricultural and urban areas,
respectively, much more than the 1 % national.average.
Chlorpyrifos was detected in 7 percent of agricultural streams, and 6
percent of mixed land-use streams. Diazinon (2 samples, .005 and .006)
and malathion (9 samples, max 0.078) were also detected in surface
water. By contrast, herbicides atrazine and malathion were detected in
every surface water sample collected.
Table III.E. 1-9. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Heartland Portion of the Northeast/
North Cental Region.
0
Land
Use
Value
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methy
Ipa rath ion
phorate
terbufos
Concentation (ug/L)
Lower Illinois R. Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.300
0.263
0.083
0.040
0.007
0.005
0.004
15.5%
0.071
0.038
0.029
0.021
0.012
0.010
0.002
30.6%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%
0.027
0.027
0.006
0.005
0.005
0.005
0.005
1.6%
0.500
0.087
0.024
0.001
0.001
0.001
0.001
0.0%
0.211
0.006
0.006
0.006
0.006
0.006
0.006
0.4%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.030
0.017
0.013
0.013
0.013
0.013
0.013
1 .2%
Agriculture
Maximum
99th
95th
90th
0.300
0.300
0.117
0.050
0.017
0.011
0.004
0.002
0.021
0.018
0.017
0.017
0.005
0.004
0.003
0.003
0.027
0.015
0.005
0.005
0.5
0.050
0.001
0.001
0.211
0.006
0.006
0.006
0.011
0.005
0.002
0.002
0.030,
0.018
0.013
0.013
I.E.1 Page 28
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0
Land
Use
Value
80th
75th
50th
Frequency
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methy
Iparathion
phorate
terbufos
Concentation (ug/L)
0.010
0.005
0.004
18.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.090
0.067
0.042
0.024
0.005
0.004
0.004
10.4%
0.002
0.002
0.002
4.8%
0.071
0.054
0.037
0.031
0.025
0.022
0.014
83.8%
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
1.8%
0.027
0.027
0.027
0.005
0.005
0.005
0.005
1.3%
0.001
0.001
0.001
0.0%
0.300
0.142
0.050
0.050
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.6%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
1.8%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
Eastern Iowa
All
Locations
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequency
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.400
0.070
0.010
0.005
0.004
0.004
0.004
5.3%
0.400
0.039
0.009
0.005
0.004
0.004
0.004
6.4%
0.057
0.007
0.005
0.002
0.002
0.002
0.002
3.4%
0.006
0.005
0.005
0.002
0.002
0.002
0.002
0.7%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.004
0.005
0.005
0.003
0.003
0.003
0.003
0.4%
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.0%
0.078
0.027
0.027
0.005
0.005
0.005
0.005
1.1%
0.078
0.027
0.027
0.005
0.005
0.005
0.005
1.4%
0.800
0.050
0.050
0.001
0.001
0.001
0.001
0.0%
0.1
0.054
0.050
0.001
0.001
. 0.001
0.001
. 0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.400
0.122
0.013
0.005
0.004
0.004
0.004
4.0%
0.057
0.011
0.005
0.002
0.002
0.002
0.002
6.4%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.8%
0.027
0.027
0.005
0.005
0.005
0.005
0.005
0.8%
0.800
0.050
0.006
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
White River Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.300
0.080
0.025
0.015
0.009
0.006
0.004
23.1%
1.100
0.380
0.130
0.058
0.025
0.017
0.005
54.4%
0.050
0.050
0.021
0.017
0.017
0.017
0.017
0.1%
0.14
0.015
0.005
0.003
0.003
0.003
0.003
1.2%
Agricultural
Maximum
99th
95th
90th
80th
75th
0.120
0.065
0.014
0.006
0.004
0.004
0.410
0.123
0.024
0.011
0.004
0.002
0.021
0.021
0.017
0.017
0.017
0.017
0.014
0.005
0.003
0.003
0.003
0.003
0.670
0.050
0.027
0.011
0.005
0.005
0.005
9.9%
0.330
0.027
0.013
0.005
0.005
0.005
0.046
0.050
0.015
0.001
0.001
0.001
0.001
1.0%
0.046
0.046
0.002
0.001
0.001
0.001
0.011
0.015
0.006
0.006
0.006
0.006
0.006
0.4%
0.010
0.006
0.006
0.006
0.006
0.006
0.060
0.020
0.011
0.002
0.002
0.002
0.002
0.0%
0.060
0.011
0.002
0.002
0.002
0.002
0.016
0.050
0.017
0.013
0.013
0.013
0.013
0.2%
0.013
0.017
0.013
0.013
0.013
0.013
I.E.1 Page 29
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0
Land
Use
Value
50th
Frequency
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methy
Iparathion
phorate
terbufos
Concentation (ug/L)
0.004
10.9%
0.002
24.0%
0.017
0.0%
0.003
0.3%
0.005
5.1%
0.001
1.6%
0.006
0.6%
0.002
0.0%
0.013
0.3%
Mixed
Maximum
99th
95th
90th
80th
75th
50th •
Frequency
0.180
0.128
0.045
0.018
0.010
0.007
0.004
17.4%
0.180
0.066
0.034
0.023
0.014
0.012
0.006
62.8%
0.050
0.050
0.050
0.021
0.017
0.017
0.017
0.3%
0.015
0.015
0.005
0.005
0.003
0.003
0.003
1.0%
0.033
0.027
0.015
0.005
0.005
0.005
0.005
2.9%
0.007
0.050
0.015
0.010
0.001
0.001
0.001
0.3%
0.011
0.015
0.006
0.006
0.006
0.006
0.006
0.3%
0.060
0.020
0.020
0.011
0.002
0.002
0.002
0.0%
0.016
0.050
0.050
0.017
0.013
0.013
0.013
0.3%
Urban
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.300
0.088
0.026
0.020
0.014
0.012
0.005
55.1%
1.100
0.600
0.358
0.240
0.136
0.100
0.043
93.8%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.140
0.019
0.005
0.003
0.003
0.003
0.003
3.4%
0.670
0.405
0.046
0.027
0.014
0.010
0.005
30.7%
0.011
0.011
0.016
0.001
0.001
0.001
0.001
•1.1%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.060
0.060
0.011
0.002
0.002
0.002
0.002
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
The Lake Erie-Lake Saint Clair Drainages (LERI) NAWQA study unit
assessed the water quality of streams draining to these lakes in parts of
Michigan, Ohio, Indiana, New York and Pennsylvania. Although historic
industrial pollution on the shores of the Great Lakes has led to the
identification of the AOCs mentioned above, about 75% of the area included
in this study unit is dedicated to agricultural use. Insecticides were included in
weekly to monthly sampling at 4 sites from 1996 to 1998. The streams
sampled drain watersheds with areas from 310 to 6330 square miles.
Chlorpyrifos and diazinon were extensively detected in agricultural, mixed
land-use and urban stream samples. Both were more frequently detected in
urban samples than agricultural samples (36% vs 13% for chlorpyrifos, 70%
vs 23% for diazinon). The maximum agricultural stream concentration of
chlorpyrifos was about 0.4 ug/l. The maximum agricultural stream
concentration of diazinon was 0.1 ug/l. Malathion and methyl parathion are
also listed as infrequent contaminants in this study.
Eighty percent of the population of the Hudson River Basin (HDSN)
NAWQA study unit, which is located almost completely in New York, derives
its drinking water from surface water supply. People drawing water from
domestic wells do so mostly from unconsolidated surficial glacial and post-
glacial aquifers. The region has more land devoted to forest than agriculture
(62% versus 25%).
Surface-water monitoring for OPs in this study unit was limited to the 46
fixed sampling sites distributed through the basin. Diazinon was extensively
detected (16%), with a maximum concentration of 0.697 ug/l. While the
highest detection of diazinon was from an agricultural stream, fewer than
20% of the samples with detections of diazinon were from agricultural
I.E.1 Page 30
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I streams. Chlorprifos was detected in little more than 1% of agricultural
1 streams, with a maximum detection of 0.024 ug/l. Malathion was detected in
I 6% of urban streams, with a maximum detection of 0.13 ug/l.
| , Diazinon and malathion were detected in ground water in this study unit.
Osl | " The monitoring program included single samples from shallow (<50 feet
O 1 deep) monitoring wells (26 urban, 18 agricultural) in the unconsolidated
^ | glacial and post-glacial deposits, and domestic wells throughout the region
^j.. 1 ranging in depth from 7 to more than 100 feet deep. Diazinon was detected
---^ | domestic and urban wells (2% of all wellls, max detection <0.1 ug/l).
CD I Malathion was detected in about 5% of domestic wells (1 % overall, max
i I concentration <0.05 ug/l).
-*— * 1
£^ I The Connecticut, Housatonic and Thames River Basins (CONN)
w I NAWQA study unit includes parts of Connecticut, Massachusetts, New
£; I Hampshire, New York and Vermont, and includes only 12 % agricultural land
(/) I (most is forested and undeveloped). Surface water is the predominant
(/) | drinking water supply, although 924 thusand of the 4.5 million people in the
CD I region had domestic wells in 1 990 (USGS Circular 1 1 55).
(/) |
| The fixed site surface water sampling program in this study included 12
| sites around the basin sampled about 15 times per year. In addition, a single
I intensive urban stream site was sampled about 40 times per year in 1 993 and
(/) I 1994. Diazinon was frequently detected in surface water, including a 92%
| frequency in urban stream samples. Chlorpyrifos (max concentration <0.1
| ug/l) and disulfoton (max concentration <0.01 ug/l) were detected in 1% and
(1) | <1% of samples, respectively. Malathion, however, was detected in 4% of
> I samples, with a maximum concentration of 7.5 ug/l. This detection did not
I occur in an agricultural stream.
| Although other insecticides such as carbofuran and permethrin were
I detected in ground water, and although diazinon was detected extensively in
I surface water, no OPs were detected in ground water in this study unit. The
I monitoring network included 163 wells sampled once each, with 120 of these
I in surficial aquifers. An additional 14 wells were sampled for a flowpath.
CL t
O| The New Jersey-Long Island Coastal Drainages (LINJ) NAWQA study
| unit includes mixed-use and urban stream samples, and agricultural, mixed
•Q | use and urban ground water samples. Only seven surface water samples
0 I were collected in a stream considered to drain solely agricultural land.
(/) I
"•> 1 An nearly equivalent number of people in the LINJ study unit derive their
I drinking water from surface water as from surficial aquifers. The surficial
\ aquifers in both the southern half of New Jersey and Long Island are coarse
I grained soils which are susceptible to pesticide contamination.
I.E.1 Page 31
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I Chlorpyrifos and diazinon were detected extensively in urban and mixed
I use surface water samples. Urban uses of chlorpyrifos and diazinon are
| currently being phased out. Only three of the urban and mixed land-use
I surface-water sampling sites had more than 50% agricultural land use. It is
i not possible to distinguish chlorpyrifos and diazinon in these samples derived
CM | from agricultural or urban/suburban use. Neither chlorpyrifos nor diazinon
O | were detected in ground water.
i The population of the Lower Susquehanna River Basin (LSUS)
| NAWQA study unit, which is located in south-central Pennsylvania and
| northeasternmost Maryland, derives 75% of its public water supply from
| surface-water sources. Public supply in this region served 1.2 million people
!' in 1992. Another 800,000 derived their drinking water from private domestic
~ | wells. The land use in the majority of this region is equally divided between
P? I agricultural and forested land (47% each- USGS Circular 1 168).
(/) i The LSUS is a study unit with relatively high frequency of OPs in surface
(/) I water. Many of these correspond with tree fruit uses simulated in PRZM-
CD [ EXAMS modeling for this region. Azinphos-methyl, for instance, was
i detected in 9% of agricultural stream samples, with a maximum concentration
I of 0.4 ug/l. Chlorpyrifos was detected in about 18% of agricultural streams
I (maximum concentration 0.09 ug/l), and diazinon was detected in little over
| 5% in agricultural streams (maximum concentration 0.055 ug/l). Methyl
(/) | parathion, which will no longer be used on tree fruits, was detected in 2
i agricultural stream samples, with a maximum concentration of 0.063 ug/l. In
I the LSUS, 187 sites sampled were once, 3 sites sampled intensively from
01 1993 to 1995.
1 Other OPs not included in the simulation modeling for the Northern
CO | Crescent were detected in the LSUS study. Malathion was detected in 8% of
33 | urban samples, and 3% of agricultural samples, with a maximum
C [ concentration of 0.129 ug/l. Ethoprop was detected in 1 .4% of samples 8
II I detections), with a maximum concentration of 0.052 ug/l.
{-s I Diazinon is the only OP detected in ground water. It was detected in 2
o 1 samples at concentrations <0.01 ug/l.
| The Western Lake Michigan Drainage (WMIC) NAWQA study unit
I provides further data on OP contamination in the Great Lakes region,
| covering eastern Wisconsin and part of the Upper Peninsula of Michigan.
(/) . | Agriculture accounts for 37% of the land use in this region, while 50% is
"^ 1 forested. Drinking water is predominantly derived from surface-water
0 I supplies in this area, mostly from Lakes Michigan and Winnebago.
(V 1
| Pesticides were included as analytes at three intensive stream sampling
| sites, and at 145 other sampling sites in agricultural, urban and mixed land-
| use areas. Diazinon was the OP most detected in this region (5%), with
[ III. E.1 Page 32
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detections ranging to about 0.05 ug/l. Chlorpyrifos, phorate, malathion and
methyl parathion were detected in no more than 3 samples each. The
maximum detection among these was a phorate detection of about 0.1 ug/l.
The Upper Mississippi River Basin NAWQA study unit is located
predominantly in Minnesota, with a small number of samples taken as well in
Wisonsin and Iowa.
Although stream-water samples were collected from streams representing
various land uses, urban streams accounted for nearly all of the OP
detections in surface water in this study unit. Diazinon was detected in 9% of
urban stream samples, and 48% of mixed land-use samples (maximum
concentration 0.3 ug/l), but in none of the 50 agricultural stream samples
collected. Similarly, chlorpyrifos was detected in 32% of urban streams, but
not in any agricultural samples. Malathion was detected in 11% of urban
samples (maximum concentration 0.08 ug/l), but only a single agricultural
sample. Two detections of ethoprop (maximum concentration 0.02 ug/l)
represent the only other OP detections in agricultural streams.
Diazinon was detected in four ground-water samples taken from wells in
"major aquifers." The maximum concentration detected was greater than 10
ug/l, which represented the highest concentration of diazinon in ground water
detected in the NAWQA program.
Table III.E.1-11. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Northern Cresent Portion of the
Northeast/ North Central Region.
Land Use
Value
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathio
n
phorate
terbufos
Concentation (ug/L)
Lower Susquehanna River Basin
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.090
0.030
0.011
0.008
0.004
0.004
0.004
14.0%
0.060
0.025
0.011
0.004
0.002
0.002
0.002
8.4%
0.034
0.034
0.017
0.017
0.017
0.017
0.017
0.0%
0.052
0.017
0.006
0.003
0.003
0.003
0.003
1.4%
0.129
0.025
0.010
0.005
0.005
0.005
0.005
3.5%
0.409
0.117
0.018
0.001
0.001
0.001
0.001
5.5%
0.063
0.012
0.006
0.006
0.006
.0.006
0.006
0.8%
0.016
0.004
0.002
0.002
0.002
0.002
0.002
0.0%
0.030
0.026
0.013
0.013
0.013
0.013
0.013
0.2%
Agriculture
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
V
0.090
0.032
0.011
0.008
0.004
0.004
0.004
17.6%
0.055
0.015
0.004
0.002
0.002
0.002
0.002
5.3%
0.034
0.034
0.017
0.017
0.017
0.017
0.017
0.0%
0.039
0.028
0.006
0.003
0.003
0.003
0.003
2.4%
0.025
0.017
0.009
0.005
0.005
0.005
0.005
3.3%
0.409
0.127
0.073
0.002
0.001
0.001
0.001
9.1%
0.063
0.012
0.006
0.006
0.006
0.006
0.006
0.8%
0.004
0.004
0.002
0.002
0.002
0.002
0.002
0.0%
0.026
0.026
0.013
0.013
0.013
0.013
0.013
0.0%
I.E.1 Page 33
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CD
Land Use
Value
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathio
n
phorate
terbufos
Concentation (ug/L)
Urban
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.047
0.024
0.014
0.010
0.004
0.004
. 0.004
16.5%
0.060
0.034
0.021
0.013
0.005
0.002
0.002
18.3%
0.034
0.033
0.017
0.017
0.017
0.017
0.017
0.0%
0.052
0.016
0.003
0.003
0.003
0.003
0.003
0.9%
0.129
0.04016
0.013
0.005
0.005
0.005
0.005
8.3%
0.044
0.04214
0.001
0.001
0.001
0.001
0.001
.1.9%
0.041
0.040
0.006
0.006
0.006
0.006
0.006
1.8%
0.016
0.004
0.002
0.002
0.002
0.002
0.002
0.0%
0.026
0.025
0.013
0.013
0.013
0.013
0.013,
0.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.082
0.033
0.010
0.008
0.005
0.004
0.004
8.1%
0.051
0.017
0.005
0.004
0.002
0.002
0.002
8.1%
0.034
. 0.034
0.034
0.021
0.017
0.017
0.017
0.0%
0.006
0.006
0.006
0.005
0.003
0.003
0.003
0.0%
0.027
0.027
0.010
0.010
0.005
0.005
0.005
0.0%
0.220
0.096
0.050
0.002
0.001
0.001
0.001
2.6%
0.012
0.012
0.012
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.004
0.004
0.002
0.002
0.002
0.0%
0.030
0.027
0.026
0.017
0.013
0.013
0.013
1.2%
Long Island/ New Jersey
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.064
0.038
0,019
0.010
0.005
0.005
0.004
24.6%
0.300
0.211
0.089
0.048
0.020
0.015
0.003
52.6%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.004,
0.003
0.003
0.003
0.003
0.0%
0.078
0.027
0.025
0.006
0.005
0.005
0.005
7.6%
0.039
0.039
0.027
0.001
0.001
0.001
0.001
1.2%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.033
0.017
0.017.
0.013
0.013
0.013
0.013
0.4%
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.030
0.027
0.014
0.004
0.004
0.004
0.004
0.0%
0.008
0.008
0.006
0.005
0.004
0.004
0.002
38.5%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.012
0.012
0.010
0.008
0.005
0.005
0.005
15.4%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
Urban
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
V
0.064
0.040
0.021
0.015
0.008
0.005
0.004
32.6%
0.300
0.232
0.113
0.060
0.028
0.020
0.004
59.1%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%
0.078
0.027
0.020
0.010
0.005
0.005
0.005
11.4%
0.039
0.039
0.007
0.001
0.001
0.001
0.001
2.3%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.033
0.018
0.013
0.013
0.013
0.013
0.013
0.8%
I.E.1 Page 34
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01
Land Use
Value
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathio
n
phorate
terbufos
Concentation (ug/L)
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.040
0.037
0.009
0.007
0.005
0.005
0.004
16.4%
0.103
0.101
0.070
0.043
0.025
0.020
0.006
60.3%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.005
0.005
0.005
0.005
0.003
0.003
0.003
0.0%
0.027
0.027
0.027
0.027
0.005
0.005
0.005
0.0%
0.050
0.050
0.050
0.050
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
Hudson River Basin
All
Locations
Agricultural
Cropland
Urban
Residential
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc-
y
Maximum
det
99th
95th
90th
80th
75th
50th
0.060
0.017
0.005
0.004
0.004
0.004
0.004
2.5%
0.024
0.013
0.004
0.004
0.004
0.004
0.004
1.3%
0.060
0.016
0.005
0.005
0.004
0.004
0.004
4.8%
0.024
0.017
0.005
0.004
0.004
0.004
0.004
0.697
0.130
0.052
0.032
0.010
0.007
0.002
28.2%
0.697
0.054
0.021
0.007
0.002
0.002
0.002
10.9%
0.550
0.237
0.119
0.076
0.045
0.039
0.015
60.6%
0.093
0.064
0.028
0.014
0.008
0.007
0.002
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.003
0.003
0.003
0.0%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.130
0.027
0.027
0.005
0.005
0.005
0.005
.1 .2%
0.027
0.027
0.005
0.005
0.005
0.005
0.005
0.0%
0.13
0.0979
0.027
0.027
0.015
0.005
0.005
5.8%
0.027
0.027
0.011
0.005
0.005
0.005
0.005
0.05
0.05 .
0.050
0.001
0.001
0.001
0.001
0.0%
0.05
0.050
0.001
0.001
0.001
0.001
0.001
0.0%
0.05
0.05
0.050
0.050
0.001
0.001
0.001
0.0%
0.050
0.050
0.002
0.001
0.001
0.001
0.001
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
I.E.1 Page 35
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Land Use
.Value
Frequenc
y
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathio
n
phorate
terbufos
Concentation (ug/L)
2.9%
34.5%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Delmarva Peninsula (1999-2001)
All
Locations
Maximum
del
99th
95th
90th
80th
75th
50th
Frequenc
V
0.014
0.009
0.005
0.005
0.005
0.005
0.004
17.1%
0.005
0.005
0.005
0.005
0.005
0.004
0.002
7.9%
0.021
0.021
0.021
0.021
0.021
0.017
0.017
0.0%
0.005
0.005
0.005
0.005
0.005
0.003
0.003
0.0%
0.034
0.029
0.027
0.027
0.027
0.012
0.005
2.6%
0.05
0.05
0.050
0.050
0.050
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.011
0.011
0.011
0.002
0.002
0.0%
0.017
0.017
0.017
0.017
0.017
0.013
0.013
0.0%
I.E.1 Page 36
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e. Region E: Humid Southeast
Only acephate and terbufos (total residues) had estimated maximum
concentrations greater than 1 ppb (Table III.E.1-12). Terbufos, acephate,
phorate, and disulfoton contributed to the peak OP cumulative loads in water.
CM More detailed discussion and analysis of the OP load in drinking water
O sources can be found in section II.E.
Table II.E.6. Predicted percentile concentrations of individual OP pesticides and
of OP cumulative distribution, Southeast Region.
Risk Assessment - 6
•; "cjjemig^
Acephate
Chlorpyrifos
Dimethoate
Disulfoton (total
residues)
Ethoprop
Methamidophos
Phorate (total
residues)
Terbufos (total
residues)
Tribufos
Cotton, Peanut,
Tobacco
Corn, Peanut,
Tobacco
Cotton
Cotton
Tobacco
Acephate
degradate
Cotton, Peanut
Corn
Cotton
OP .Cumulative Concentration in
Methamidophos Equivalents
**»M.axm<-
1.7e+00
2.66-01
7.4e-02
4.3e-02
2.26-01
2.16-01
6.66-01
1.5e+00
2.4e-02
3.8e+00
4.36-02
9.96-02
1.26-02
2.8e-02
1.4e-01
5.2e-03
3.96-02
4.0e-01
1.6e-02
1.1e+00
•5>&95th1Psi
3.1e-03
5.66-02
2.7e-03
1 .6e-02
4.8e-02
1 .7e-04
1.7e-03
1.16-01
1.1e-02
3.6e-01
"SR^OttiMp
7.06-04
3.8e-02
1.0e-03
1 .2e-02
2.96-02
9.86-06
4.76-05
3.9e-02
9.6e-03
1.6e-01
2.16-05
2.2e-02
2.3e-04
7.8e-03
1.5e-02
4.56-08
2.16-09
6.56-03
7.8e-03
6.56-02
ij^iBliiiHifiHl
«W^&»«K*S*B?W£WS'
msttflMi
1.86-06
1.8e-02
7.76-05
6.5e-03
1.2e-02
1.46-08
1.46-11
1.66-03
7.3e-03
4.96-02
saMaEKaaiBBfiB^afe.!*
|p||isypfp|||
1.76-08
5.86-03
9.16-07
3.46-03
4.96-03
4.2e-10
1.0e-12
1.2e-04
5.4e-03
1.86-02
13
E
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0
i. Comparison of Monitoring Data versus Model Estimates
The Albemarle-Pamlico Drainage Basin (ALBE) NAWQA study unit,
located primarily in the Piedmont and Coastal Plain physiographic provinces
of southeastern Virginia and northeastern North Carolina, includes the area
identified as a vulnerable watershed for the OP cumulative assessment. The
NAWQA study included chlorpyrifos, disulfoton, ethoprop, phorate, and
terbufos in its monitoring program.
Chlorpyrifos was detected in 14% of agricultural streams, at a maximum
of 0.058 ug/l, roughly equivalent to the estimated 95th percentile
concentration. The estimated concentrations and measured concentrations in
the ALBE agricultural streams were within a factor of 10 of each other at the
90th and greater percentiles. Ethoprop was detected in 4% of all samples,
with a maximum detection of 0.8 ug/l in an agricultural stream, greater than
the estimated peak of 0.2 ug/l. Phorate was detected in little more than 1% of
samples, with a maximum concentrations of about 0.03 ug/l, roughly
equivalent to the 99th percentile estimated concentration. Terbufos was
detected in a single mixed land-use sample at 0.01 ug/l, slightly less than the
90th percentile estimated concentration.
I.E.1 Page 37
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CD
For chlopyrifos, both estimated and observed concentrations in Chicod
Creek were consistent except for the 80th percentile and higher, at which the
estimated values dramatically increased (Figure III.E.1-9). Ethoprop, another
contributor chemical, was only detected once in Chicod Creek. .
3.0E-01
* Estimated
• Chicod Creek
20 40 60 80 100 120
Percentile
I Figure III.E.1-9. Comparison of observed and estimated chlorpyrifos
{ concentrations in the Humid Southeast Region.
ii. Summary of NAWQA Monitoring Data in the Region
The Albemarle -Pamlico Drainage Basin (ALBE) NAWQA study unit is
located primarily in the Piedmont and Coastal Plain physiographic provinces
of southeastern Virginia and northeastern North Carolina. Nearly equivalent
portions of the population derived drinking water from surface water and
ground water in 1990, with one-third of the population drawing water from
domestic wells.
Shallow wells (< 50 feet) in unconsolidated surficial aquifers were
sampled because they were most likely to be vulnerable to contamination.
Several public supply wells were also included to see if pumping drew
contamination from the surficial wells. Diazinon was detected in 7% of
ground-water samples, and chlorpyrifos in a single ground-water sample. The
USGS Circular 1157 indicates that both were detected in the agricultural
(corn-soybean) land-use study, but does not indicate whether some of the
diazinon detections occurred in the Virginia Beach urban land-use study. The
maximum concentration of diazinon in ground water was about 0.1 ug/l. The
single detection of chlorpyrifos was <0.01 ug/l.
Diazinon (9.5%) and chlorpyrifos (13.9%) were the OPs most frequently
detected in agricultural streams, although both were more often detected in
I.E.1 Page 38
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mixed land-use streams. Diazinon was detected at a maximum concentration
of 0.11 ug/l in these streams, and chlorpyrifos at a maximum of 0.058 ug/l.
Malathion was detected in 7.7% of all samples, with a maximum detection of
0.055 ug/l. Ethoprop was detected in 4.4% of all samples, with a maximum
detection of 0.8 ug/l in an agricultural stream. Phorate and azinphos methyl
CNJ were detected in little more than 1% of samples each, with maximum
O concentrations of about 0.03 ug/l. Terbufos was detected in a single mixed
land-use sample at 0.01 ug/l. Surface water was collected at four intensive
sampling sites, and 66 other stream sites sampled one to six times in the
study.
CD
i The Apalachicola-Chattahoochee-Flint River Basin (ACFB) NAWQA
study site extends from north of Atlanta along the Georgia-Alabama border
through the Florida panhandle to the Gulf of Mexico. The northern portion of
the study unit is in the Piedmont physiographic province, and the southern
portion in the Coastal Plain. Ninety-three percent of the population in the
CO Piedmont derived drinking water (from surface water in 1990, while surface
CO water and ground water served nearly equivalent populations in the Coastal
CD Plain. Nearly half of the ground water in the basin was supplied by the
CO vulnerable, karst limestone, Upper Floridan aquifer.
Pesticides were most frequently detected in the karst recharge areas of
the Upper Floridan aquifer, but OPs were rarely detected. USGS Circular
CO 1164 indicates that chlorpyrifos and terbufos were both detected once at
about 0.01 |jg/l, but the dataset available on the study unit world wide web
page does not include these detections. Diazinon was detected twice in the
Q) urban land-use study. Malathion was detected once in the agricultural land-
>• use study at a concentration of 0.011 ug/l.
Diazinon, chlorpyrifos and malathion were frequently detected in this study
unit, but almost exclusively in urban or suburban stream samples. Malathion
was detected in an urban stream with a maximum concentration of 0.14 ug/l.
Ethoprop was detected twice in urban or suburban streams, and once in an
agricultural stream (maximum concentration 0.021 ug/l). Azinphos-methyl,
disulfoton and terbufos were detected once each in urban or suburban
n streams, at concentrations of 0.018 ug/l or less.
The Potomac River Basin (POTO) NAWQA study unit is comprised of
parts of Virginia, West Virginia, Maryland, Pennsylvania and the District of
0 Columbia. Surface water is the dominant source of drinking water in this
CO basin, although nearly 800,000 people in the basin relied on domestic wells in
1990.
CD
ry I Surface-water sites included for intensive sites sampled 24 times a year
I for two years in agricultural and urban areas. Twenty-three tributaries with
I watersheds of greater than 100 square miles were sampled once each, and
I 25 to 39 tributaries with smaller basins were sampled once each for three
I III.E.1 Page 39
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years. Diazinon was the most detected OP, found in 24% of samples, with a
maximum concentration of 1.4 ug/l.Chlorpyrifos was detected in 8% of
samples, with a maximum concentration of 0.041 ug/l. Methyl parathion was
detected in 2% of samples, but some portion of these detections might be
due to since-cancelled orchard uses. Malathion, ethoprop and azinphos
methyl were, also detected in fewer than 5% of samples.
Ground-water was sampled one time from each of 48 wells in the
Piedmont and physiographic province from the Washington DC metropolitan
area through central Maryland. Another 54 agricultural and 3 forest region
wells were sampled once each to the west in the Valley and Ridge
a | physiographic region. Chlorpyrifos is described as an important agricultural
-*=> I chemical in the Potomac River Basin, with use on corn, alfalfa and apples. It
£= I was detected in two ground-water samples, with a maximum concentration
® I -of about 0.05 ug/l. Diazinon was detected in ground water three times, with a
£ I maximum concentration of about 0.01 ug/l, and malathion once at <0.005
(/) I ug/l. Neither is listed as a major agricultural chemical in the region.
V) |
CD 1 The Santee River Basin and Coastal Drainages (SANT) NAWQA study
^ I unit includes much of South Carolina, and extends into southwestern North
Carolina. Eighty-six percent of drinking water in this region is from rivers and
reservoirs, although rural regions which are not on public supply rely on
domestic wells. In the north of the study unit, the relatively undeveloped land
in the Blue Ridge physiographic province has little affect on water quality.
However, development is more extensive in the Piedmont, and the rivers
which provide drinking water are well-regulated, as 85% of water use is for
the production of energy. Toward the coast, slow-moving rivers in the Coastal
Plain run through marshland and row-crop farmland.
CO 1 Analysis for pesticides was included in intensive (3 sites) and fixed-site
13 | (13 sites) surface water studies over a range of land uses, and at 16 urban
C I sampling sites. Chlorpyrifos, diazinon and malathion were the only OPs
EE [ detected more than once. All three were detected in more than half of urban
E samples, but only Chlorpyrifos (60%) was detected in more than 10 % of ,
agricultural samples. Chlorpyrifos was detected at a maximum concentration
of 0.03 pg/l in an agricultural stream, and malathion at 0.216 in an urban
stream. Methyl parathion was detected once in an urban stream at 0.013 ug/l.
Diazinon was detected in a single agricultural well at around 0.005 ug/l,
and in a well from the Sandhills aquifer at about 0.06 ug/l. Chlorpyrifos and
diazinon were detected in 2 and 3 urban wells, respectively. No other OPs
were detected in ground water.
I.E.1 Page 40
-------
Table III.E. 1-13. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Southern Seaboard Portion of the
Humid Southeast Region.
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Urban
•
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All
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Agricultural
Cropland
• Value.' •
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
chlorpyrifos
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
u, • ,; .i^-i*',"'' , Concentation, (ug/L) , • ,- >-;•„,
0.004
0.004
0.004
0.0%
0.0.07
0.006
0.004
0.004
0.004
0.004
0.004
2.6%
0.095
0.084
0.022
0.015
0.011
0.010
0.005
67.6%
0.006
0.005
0.005
0.005
0.004
0.004
0.004
1.5%
0.170
0.059
0.016
0.011
0.005
0.005
• 0.004
25.6%
0.099
0.005
0.004
0.004
0.004
0.004
0.002
38.5%
0.015
0.010
0.002
0.002
0.002
0.002
0.002
2.6%
0.323
0.298
0.102
0.048
0.032
0.030
0.018
80.9%
0.015
0.011
0.005
0.005
0.004
0.002
0.002
7.7%
2.800
0.255
0.063
0.032
0.016
0.012
0.002
46.5%
0.012
0.005
0.002
0.002
0.017
0.017
0.017
0.0%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.021
0.021
0.021
0.021
0.017
0.017
0.017
0.0%
0.018
0.021
0.017
0.017
0.017
0.017
0.017
0.2%
0.021
0.021
0.017
0.017
0.003
0.003
0.003
0.0%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.003
0.003
0.003
0.0%
0.021
0.005
0.005
0.003
0.003
0.003
0.003
0.5%
0.010
0.005
0.003
0.003
0.005
0.005
0.005
15.4%
0.018
0.01306
0.005
0.005
0.005
0.005
0.005
2.6%
0.216
0.18518
0.089
0.059
0.028
0.027
0.008
48.5%
0.0886
0.049
0.027
0.027
0.005
0.005
0.005
6.2%
0.140
0.045
0.027
0.009
0.005
0.005
0.005
6.7%
0.009
0.027
0.005
0.005
0.001
0.001
0.001
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.05
0.05
0.050
0.001
0.001
0.001
0.001
0.0%
0.050
0.050
0.050
0.050
0.001
0.001
0.001
0.0%
0.11
0.05
0.050
0.001
0.001
0.001
0.001
0.2%
0.05
0.050
0.001
0.001
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
. 0.006
0.006
0.006
0.006
0.0%
0.0125
0.008
0.006
0.006
0.006
0.006
0.006
1.5%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.002
0.002
0.002
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.011
0.002
0.002
0.002
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.002
0.002
0.013
0.013
0.013
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
0.017
0.017
0.017
0.013
0.013
.0.013
0.013
0.0%
0.017
0.017
0.017
0.017
0.013
0.013
0.013
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.2%
0.017
0.017
. 0.013
0.013
I.E.1 Page 42
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Residential
Mixed
&
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
*?v ofc * »*| ..ir-^^ *,;*
0.004
0.004
0.004
0.6%
0.170
0.085
0.040
0.020
0.011
0.010
0.004
50.0%
0.018
0.014
0.010
0.008
0.005
0.005
0.004
21.8%
0.002
0.002
0.002
0.6%
2.800
0.366
0.124
0.067
0.033
0.029
0.011
81 .9%
0.103
0.063
0.029
0.019
0.013
0.012
0.005
52.8%
^^wPs'P^w™''^™?!™?^^^
0.017
0.017
0.017
0.0%
0.018
0.021
0.017
0.017
0.017
0.017
0.017
0.4%
0.003
0.003
0.003
0.6%
0.021
0.008
0.003
0.003
0.003
0.003
0.003
0.9%
0.021
0.021
0.021
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.005
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
1.3%
0.14
0.06669
0.027
0.017
0.005
0.005
0.005
11.6%
0.044
0.035
0.027
0.016
0.005
0.005
0.005
6.3%
*fBj^SKSji39|9H5|HiE||j
RS(ilJ!*il!i'*iM'*P^wBB3ppfi^
0.001
0.001
0.001
0.0%
0.11
0.05
0.001
0.001
0.001
0.001
0.001
0.4%
0.300
0.070
0.050
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.0%
T^tSH * 1 1 Iff*?"**- %
IHIBBBHBff
0.002
0.002
0.002
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.011
0.011
0.011
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.0%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.4%
0.017
0.017
0.017
0.013
0.013
0.013
0.013
0.0%
Georgia portion of GA-FL coastal Plain
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.028
0.017
0.007
0.005
0.004
0.004
0.004
8.9%
0.097
0.068
0.010
0.005
0.002
0.002
0.002
1 1 .6%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.3%
Agricultural
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.021
0.014
0.006
0.004
0.004
0.004
0.004
6.7%
0.025
0.007
0.002
0.002
0.002
0.002
0.002
1 .4%
0.021
0.021
0.017
0.017
0.017
0.017
0.017
0.5%
0.018
0.010
0.005
0.003
0.003
0.003
0.003
4.0%
0.226
0.027
0.026
0.005
0.005
0.005
0.005
5.2%
0.166
0.073
0.050
0.001
0.001
0.001
0.001
0.6%
0.200
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.003
0.011
0.002
0.002
0.002
0.002
0.002
0.3%
0.018
0.017
0.013
0.013
0.013
0.013
0.013
0.3%
0.018
0.009
0.005
0.003
0.003
0.003
0.003
3.3%
0.025
0.025
0.007
0.005
0.005
0.005
0.005
2.9%
0.166
0.079
0.001
0.001
0.001
0.001
0.001
1 .0%
0.200
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.003
0.011
0.002
0.002
0.002
0.002
0.002
0.5%
0.018
0.017
0.013
0.013
0.013
0.013
0.013
0.5%
Mixed
Maximum
99th
95th
0.028
0.018
0.008
0.097
0.087
0.026
0.021
0.021
0.021
0.015
0.012
0.006
0.226
0.033
0.027
0.3
0.05
0.050
0.050
0.032
0.006
0.020
0.011
0.011
0.017
0.017
0.017
I.E.1 Page 43
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. Land Use
' Value V
90th
80th
75th
50th
Frequenc
V
chlorpyrifbs
'*'' v» *
0.006
0.004
0.004
0.004
13.5%
diazinon
disulfoton
ethoprop
malathion
azinphos
methyl
methyl
parathion
phorate
, ",. •• V i Concentation (ug/L)
0.011
0.007
0.006
0.002
31.5%
0.017
0.017
0.017
0.017
0.0%
0.005
0.003
0.003
0.003
5.4%
0.017
0.005
0.005
0.005
9.9%
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.0%
terbufos
0.013
0.013
0.013
0.013
0.0%
The NAWQA Upper Tennessee River Basin (UTEN) study unit includes
Henderson County, North Carolina, the OP high-use area chosen for the
Eastern Uplands surface-water modeling. The study area is located primarily
in western North Carolina, eastern Tennessee, and southwest Virginia.
Sampling in this study occurred between 1995 and 1999, and included nine of
the OP insecticides that are part of the cumulative water assessment.
Surface-water monitoring was concentrated in the unregulated portions of
the Tennessee River, which is extensively dammed for generation of
hydroelectric power. Chlorpyrifos (10% of samples), diazinon (12%) and
malathion are the only OPs detected in 428 samples taken biweekly between
March and November, 1996. The maximum concentration of diazinon reported
was 0.59 ug/l. The frequency of detection for diazinon was greater for
sampling locations identified as "mixed land use" while the frequency of
detection for chlorpyrifos was greater from "agricultural" sampling sites.
No OPs were detected in ground-water sampling for the Upper Tennessee
River (UTEN) NAWQA study. Thirty monitoring wells were located next to
tobacco fields, while 30 additional wells and 35 springs were randomly
selected from around the Valley and Ridge portion of the study site. Each well
or spring was sampled a single time. Domestic wells are the main source of
drinking water for one-third of the popluation in the UTEN study region.
The Kanawha-New River Basin (KANA) NAWQA study site, located
primarily in south-central West Virginia and southwest Virginia, represents a
less agricultural region with less OP use. Chlorpyrifos, diazinon and malathion
were detected in the KANA study. Diazinon and malathion were detected in
surface water.
Chlorpyrifos was detected in one of 60 domestic or supply wells in the
Kanawha-New River (KANA) NAWQA study at a concentration of 0.004 ppb.
Thirty of the wells were located in the mountainous coal-mining Appalachian
Plateau physiographic province in West Virginia. Chlorpyrifos was detected in
a well in the relatively more agricultural Blue Ridge physiographic province, in
the southern portion of the study unit. Domestic wells are reported to supply
drinking water to thirty percent of the population in the KANA study unit.
The Allegheny and Monongahela River Basins (ALMN) study unit is
located in northeastern West Virginia and western Pennsylvania. Agriculture
I.E.1 Page 44
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accounts for only 30% of land use in the study unit, "commonly low-intensity
pasture, dairy and hay." Diazinon and chlorpyrifos are the only active OPs
detected in this monitoring program. Diazinon was detected at two of 18
agricultural stream samples, and in seven of 26 (31%) urban stream samples,
with maximum concentrations of about 0.1 ug/l. Chlorpyrifos is also reported
as having been detected in surface water. Surface water is the main source of
drinking water in the Pittsburgh region.
Diazinon was also detected in ground water in six of 58 samples from
major aquifers in the Allegheny-Monongahela River (ALMN) NAWQA study,
with a maximum concentration of 0.007 ppb. Domestic wells are reported by
the USGS as the major source of drinking water for people living in rural areas
of the ALMN study unit.
Table III.E.1-14. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Eastern Uplands Portion of the Humid
Southeast Region.
lajid Use1
i?«iSv'4h
jjWrifos
ifiHpRipi
m
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Upper Tennessee River Basin
All
Locations
Maximum
95th
90th
75th
Frequency
0.033
0.005
0.005
O.004
10.1%
0.590 1
0.005
0.004
O.002
12.1%
<0.021
O.017
<0.017
<0.017
0.0%
0.018
<0.003
<0.003
<0.003
0.4%
0.046 '
<0.005
<0.005
<0.005
1 .4%
0.0386
<0.050
<0.001
<0.001
0.2%
<0.006
<0.006
<0.006
<0.006
0.0%
<0.011
<0.002
<0.002
<0.002
0.0%
<0.017
<0.013
<0.013
<0.013
0.0%
Agriculture
Forestry
Vlaximum
95th
90th
75th
Frequency
Vlaximum
95th
90th
75th
Frequency
0.033
0.006
0.005
<0.004
13.2%
0.012
0.005
<0.005
<0.004
5.0%
0.006
0.004
<0.002
<0.002
3.9%
<0.021
O.017
O.017
<0.017
0.0%
0.066
0.008
0.005
<0.002
16.3%
<0.021
<0.021
<0.017
O.017
0.0%
<0.005
<0.003
<0.003
<0.003
0.0%
0.018
<0.005
<0.003
<0.003
1.3%
0.015
<0.008
<0.005
<0.005
2.0%
0.015
<0.027
<0.005
<0.005
1.3%
<0.11
<0.050
<0.001
<0.001
0.0%
0.0386
<0.050
<0.005
<0.001
1.3%
<0.006
<0.006
O.006
<0.006
0.0%
<0.006
<0.006
<0.006
<0.006
0.0%
<0.011
<0.002
<0.002
<0.002
0.0%
<0.017
O.013
<0.013
<0.013
0.0%
0.011
<0.011
<0.002
<0.002
0.0%
0.017
O.017
<0.013
<0.013
0.0%
Mixed
Maximum
95th
90th
75th
Frequency
0.014
0.005
<0.004
<0.004
8.6%
0.040
0.005
0.005
<0.002
14.8%
<0.021
O.017
<0.017
O.017
0.0%
0.015
<0.003
<0.003
<0.003
0.5%
0.0061
<0.005
<0.005
<0.005
0.5%
O.700
<0.200
<0.034
<0.001
0.0%
<0.006
<0.006
<0.006
<0.006
0.0%
O.011
<0.002
<0.002
<0.002
0.0%
<0.017
<0.013
<0.013
<0.013
0.0%
(1) The maximum concentrations of diazinon and malathion occurred at a sample site located in a watershed
influenced by mining. Sample sites representing watersheds with mining land uses were not broken out
separately in this summary table.
Kanawha-New River Basin
All
Locations
Maximum
95th
90th
0.004
<0.004
<0.004
0.004
O.002
O.002
<0.017
<0.017
<0.017
<0.003
<0.003
<0.003
0.005
<0.005
<0.005
<0.06
<0.001
<0.001
<0.006
<0.006
<0.006
<0.002
<0.002
<0.002
<0.013
<0.013
<0.013
I.E.1 Page 45
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CM
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I
Land Use
Value
75th
Frequency
• chlor-
py'rifos
diazinon
'•« .'-
<0.004
4.4%
O.002
1.5%
disulfoton
ethoprop
malg-
thion
azinphos
methyl
Concentration, ug/L ,
<0.017
0.0%
<0.003
0.0%
<0.005
1.5%
O.001
0.0%
methyl
parathion
<0.006
0.0%
phorate
<0.002
0.0%
terbufos
<0.013
0.0%
NOTE: Because of the low number of samples (68 samples were analyzed for OPs) and the low frequency of
detects, monitoring data for this study unit were not broken down by land use within the watershed.
Allegheny and Monongahela River Basin
All
Locations
Maximum
95th
90th
75th
Frequency
0.010
<0.004
<0.004
<0.004
7.4%
0.097
0.027
0.013
0.003
27.2%
<0.017
<0.017
<0.017
O.017
0.0%
O.003
<0.003
-------
f. Region F: Lower Midwest
CM
O
Estimated maximum concentrations of malathion and terbufos (parent plus
sulfoxide/sulfone) were in the single parts per billion (Table III.E.1-15). More
detailed discussion and analysis of the OP load in drinking water sources can
be found in section II.F.
Table III.E.1-15. Predicted
and of the cumulative OP
percentile concentrations of individual OP pesticides
distribution, Lower Midwest Region
Chemical
Acephate
Chlorpyrifos
Dicrotophos
Dimethoate
Malathion
Methamidophos
MethylParathion
Phorate
Phostebupirim
Terbufos
Tribufos
Crop/Use
Cotton
Alfalfa.Corn,
Cotton, Sorghum
Cotton
Corn.Cotton,
Wheat
Cotton
Acephate
degradate
Alfalfa, Cotton
Cotton
Corn
Corn
Cotton
OP cumulative in methamidophos
eauivalents
Concentrations in ug/L (ppb)
Max
1.4e-01
1.3e-01
3.9e-02
6.5e-02
1.5e+00
4.66-02
6.86-02
4.26-02
6.96-02
1 ,4e+00
6.1e-02
3.7e+00
99th
1.26-02
5.96-02
7.9e-03
2.16-02
8.2e-02
8.5e-04
1.56-02
3.86-03.
3.26-02
4.96-01
3.66-02
1.3e+00
95th
1.0e-03
2.96-02
2.46-03
7.06-03
3.4e-02
3.16-05
4.46-03
1.2e-04
1.4e-02
1.7e-01
2.36-02
4.8e-01
90th
1.9e-04
1.8e-02
9.3e-04
4.16-03
1.5e-02
1.1e-06
2.46-03
2.0e-06
8.96-03
7.96-02
1.96-02
2.36-01
80th
2.0e-06
1.8e-02
9.36-04
4.16-03
1.5e-02
1.16-06
2.46-03
2.0e-06
8.96-03
7.96-02
1.96-02
5.76-02
75th
1.0e-07
8.4e-03
6.7e-05
1.66-03
1.86-03
3.16-10
5.36-04
1.76-11
3.76-03
8.66-03
1.36-02
3.0e-02
50th
1.1e-09
3.5e-03
2.66-06
3.36-04
6.1e-06
1.4e-11
3.36-05
2.06-13
1.46-03
4.46-04
9.46-03
4.66-03
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i. Comparison of Monitoring Data versus Model Estimates
A comparison of estimated concentrations for individual OP pesticides with
NAWQA monitoring indicate that, except for terbufos, NAWQA sites in the
Trinity River Basin had higher detections than were predicted for this regional
assessment. For methyl parathion, the highest monitoring detect was an order
of magnitude greater than the estimated maximum concentration. Although
in-depth analysis of use has not been made, it is possible that the methyl
parathion discrepancies may reflect differences resulting from uses that have
been canceled and are not reflected in the modeling. For chlorpyrifos and
malathion, the highest monitoring detections were twice as great as the
highest estimated concentration. These differences are not great, and may
reflect contributions from urban uses. The estimated concentrations for
terbufos include parent terbufos plus the sulfoxide and sulfone transformation
products while NAWQA only analyzed for the less persistent and less mobile
parent.
Although diazinon has been frequently detected in the Trinity River Basin,
particularly in urban streams, the latest MASS surveys indicate little or no
agricultural uses of diazinon in the Central Hills area. Detections of diazinon
in the Trinity River Basin may reflect residential uses which are being
I.E.1 Page 47
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canceled or uses on other crops during the sampling period that are not
reflected in current use surveys.
ii. Summary of NAWQA Monitoring Data in the Region
CM The Trinity River Basin (TRIM) study unit is the NAWQA monitoring
O program closest to the Central Hills of Texas, the high-use area the Agency
chose for the PRZM EXAMS surface-water modeling scenario. More than 90%
of water in this basin is supplied by surface water, mostly in reservoirs (USGS
Circular 1171). Much of the agricultural land is used for grazing cattle.
CO
i Diazinon, chlorpyrifos and malathion were detected in 97%, 71% and 32%
•*-* of urban samples, respectively.The maximum concentration of diazinon in
urban samples was 2.3 ug/l. Diazinon was also detected frequently in
agricultural samples (46%) and rangeland streams (38.5%), with a maximum
detection of 0.16 ug/l. Azinphos-methyl, methyl parathion and disulfoton were
00 1 detected in less than 3% of agricultural samples. Of these azinphos had the
GO highest maximum concentration, 0.55 ug/l.
Ground-water sampling was done at outcrop areas of the four major
aquifers in the study unit; confining units or minor aquifers are present at the
surface (outcrop) over more than half of the area of the TRIM. Diazinon was
detected in nearly half of the samples drawn from the 24 wells in the Trinity
(/) aquifer outcrop. However, half of the wells also had salinity higher than
acceptable for potable water. The maximum concentration of diazinon in
ground water was about 0.1 ug/l. It is not clear whether these detections were
associated with urban or agricultural applications of diazinon.
The South-Central Texas (SCTX) NAWQA study unit includes the city of
San Antonio. Ground water is the predominant source of drinking water in this
area. The water is mostly derived from the Edwards Aquifer, which is one of
the most productive in the world. The Edwards aquifer is recharged by surface
water where precipitation and streams meet the fractured and faulted Edwards
at its outcrop. This hydraulic connection makes stream and river-water quality
important for the Edwards aquifer, which supplies about 70% of water
withdrawn in the study unit. The Trinity aquifer is locally important in the Hill
Country in the north of SCTX, but is generally less productive than the
Edwards.
Ground-water monitoring included domestic wells in the area where
(/) surface-water and precipitation recharge the Edwards aquifer, public supply
wells in the confined part of the Edwards aquifer, and domestic wells from the
0 less permeable Trinity aquifer. Diazinon was the only OP detected, three times
in shallow urban ground water, once in a major aquifer sample, each time <0.1
ug/l. No agricultural ground-water samples were collected.
I.E.1 Page 48
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Three surface-water sampling sites were located at urban and agricultural
streams. These were sampled weekly to monthly from January, 1997 to
March, 1998. Diazinon was detected in 38% of agricultural samples with a
maximum concentration of 0.059 ug/l. Chlorpyrifos (max 0.008 ug/l) was
detected in 21% of agricultural samples, and malathion in 9% of all samples
(max 0.142 ug/l).
In the Central Nebraska Basins (CNBR) NAWQA study unit, ground
water is the major source of drinking water. The major source of ground
water, the Platte River alluvial aquifer, is hydraulically connected with the
North Platte River, both through discharge to the river and increased recharge
from the river due to pumping from the aquifer. Sampling included single
samples from 11 shallow wells installed in this aquifer. No active OP was
detected in ground-water in this limited study (fonofos was detected twice).
A second ground-water study included 61 wells installed in two clusters:
one in a recharge area in a meadow near corn fields, and another in and north
of a public-supply wellfield on Indian Island in the Platte River near Grand
Island. The intention was to study land-use effects on shallow ground-water
along the flow path. This study was useful in further showing that the alluvial
aquifer shows increasing influence from the Platte River from upstream to
downstream. While it did measure pesticide concentrations at a wellfield
designed to be protected from agricultural ground-water contamination, it was
not designed to evaluate acute exposure to pesticides. No OPs were detected
in this study.
OPs were included at four fixed surface-water sampling sites on the Platte
River and its tributaries. These were located in areas of heavy corn
. production. All were sampled monthly, but two of these also were sampled
more intensively in the spring and summer of 1992 (including 12 weeks of
alternate-day sampling). These two were located in the glaciated area in the
eastern, downstream portion of the study unit.
Chlorpyrifos, diazinon and malathion were the most frequently detected
OPs. Diazinon was detected mostly in urban or mix-use streams, while at least
of the detections of the other two occurred in agricultural streams. Chlorpyrifos
had the highest single concentration detected of the three in agricultural
streams, at 0.13 ug/l. Methyl parathion, azinphos-methyl and terbufos were
detected in less than 3% of samples. A detection of 0.27 ug/l terbufos was the
highest concentration detected for any OP.
Table III.E.1-16. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Lower Midwest Rec
I.E:1 Page 49
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*Land Llse-
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
chlorpyrifos
' diazinon
disulfoton
ethopro
'p ' '
malathibn
azinphos
methyl
methyl
parathion
phorate
terbufos
»'!>'"" • -v' : , •>* '• <% . '• , Concentation (ug/L), - .,.,,".
0.110
0.069
0.033
0.017
0.009
0.005
0.004
25.7%
2.300
1.186
0.396
. 0.186
0.061
0.037
0.008
61.3%
0.05
0.059
0.017
0.017
0.017
0.017
0.017
0.6%
0.018
0.012
0.003
0.003
0.003
0.003
0.003
0.0%
0.380
0.144
0.030
0.014
0.005
0.005
0.005
9.2%
0.55
0.135
0.001
0.001
0.001
0.001
0.001
1 .6%
0.230
0.044
0.006
0.006
0.006
0.006
0.006
1.6%
0.016
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
,
Agriculture
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.048
0.012
0.009
0.004
0.004
0.004
0.004
9,4%
0.160
0.110
0.024
0.016
0.011
0.009
0.002
46.2%
0.05
0.060
0.017
0.017
0.017
0.017
0.017
0.6%
0.012
0.012
0.003
0.003
0.003
0.003
0.003
0.0%
0.038
0.026
0.010
0.005
0.005
0.005
0.005
2.9%
0.55
0.437
0.001
0.001
0.001
0.001
0.001
1 .8%
0.230
0.044
0.006
0.006
0.006
0.006
0.006
2.9%
0.011
0.011
0.002
0.002
0.002
. 0.002
0.002
0.0%
0.018
0.016
0.013
0.013
0.013
0.013
0.013
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
Range
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.004
0.004
0.004
0.004
0.004
0.004
0.004
0.0%
Urban
Maximum
99th
95th
90th
80th .
75th
50th
Frequency
0.110
0.089
0.068
0.050
0.032
0.027
0.011
71.2%
0.037
0.036
0.032
0.024
0.008
0.005
0.002
38.5%
0.017
0.017
0.017
0.017
0.017
0.017
0.017
7.7%
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.0%
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.0%
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.0%
0.013
0.013
0.013
0.013
0.013
0.013
0.013
0.0%
2.300
2.040
1.175
0.665
0.420
0.375
0.140
97.0%
0.021
0.018
0.017
0.017
0.017
0.017
0.017
0.0%
0.018
0.017
0.003
0.003
0.003
0.003
0.003
0.0%
0.38
0.237
0.140
0.068
0.029
0.022
0.005
31.8%
0.14
0.114
0.053
0.001
0.001
0.001
0.001
3.0%
0.051
0.050
0.006
0.006
0.006
0.006
0.006
0.0%
0.016
0.016
0.002
0.002
0.002
0.002
0.002
0.0%
0.018
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
Mixed
Maximum
99th
95th
90th
80th.
75th
50th
Frequency
0.022
0.020
0.014
0.010
0.005
0.004
0.004
22.2%
0.340
0.271
0.075
0.072
0.053
0.048
0.030
92.6%
0.021
0.020
0.017
0.017
0.017
0.017
0.017
0.0%
0.005
0.004
0.003
0.003
0.003
0.003
0.003
0.0%
0.0339
0.031
0.022
0.009
0.005
0.005
0.005
11.1%
0.050
0.037
0.001
0.001
0.001
0.001
0.001
0.0%
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.0%
0.011
0.009
0.002
0.002
0.002
0.002
0.002
0.0%
0.017
0.016
0.013
0.013
0.013
0.013
0.013
0.0%
South-Central Texas
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.1.05
0.010
0.007
0.005
0.004
0.004
0.004
19.2%
0.527
0.210
0.095
0.063
0.029
0.020
0.005
56.0%
0.0651
0.021
0.021
0.017
0.017
0.017
0.017
0.5%
0.128
0.008
0.005
0.003
0.003
0.003
0.003
0.5%
0.142
0.084
0.027
0.012
0.005
0.005
0.005
9.3%
0.18
0.050
0.050
0.001
0.001
0.001
0.001
0.6%
0.132
0.006
0.006
0.006
0.006
0.006
0.006
0.5%
0.083
0.011
0.011
0.002
0.002
0.002
0.002
•0.5%
0.109
0.017
0.017
0.013
0.013
0.013
0.013
1.1%
I.E.1 Page 50
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Agriculture
Range
PI
Maximum
99th
95th
90th
80th
75th
50th
Frequency
& **\*% v^
J,*
0.008
0.007
0.006
'0.005
0.004
0.004
0.004
20.6%
0.059
0.047
0.017
0.007
0.005
0.005
0.002
38.2%
f fcK^V^
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.^11%-';
Frequency
chlorpyrifos
"?
diazinon '•
disulfoton
ethoprp
> P"
malathion
azinphos
methyl
methyl
parathion
phorate
terbufos
,>••',,•• ' - •/;*-•» Concentatipn;(ug/L)\ ' _^
25.9%
8.6%
0.0%
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequency
0.140
0.109
0.047
0.016
0.005
0.004
0.004
17.8%
0.0394
0.025334
0.01454
0.009
0.005
0.005
0.002
39.9%
0,021
0.021
0.017
0.017
0.017
0.017
0.017
0.0%
0.0%
5.9%
0.5%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%.
0.0444
0.029
0.020
0.005
0.005
0.005
0.005
5.5%
0.050
0.050
0.001
0.001
0.001
0.001
0.001
0.0%
2.7%
0.0%
0.5%
0.028
0.022
0.006
0.006
0.006
0.006
0.006
3.1%
'0.011
0.011
0.010,,
0.002
0.002
0.002
0.002
0.0%
0.270
0.019
0.013
0.013
0.013
0.013
0.013
1.2%
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I.E.1 Page 52
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g. Region G: Mid-South
Maximum estimated concentrations of acephate, dicrotophos, and terbufos
were in the single parts per billion, while the maximum estimated
concentration of malathion was greater than 10 ppb (Table III.E.1-17). More
detailed discussion and analysis of the OP load in drinking water sources can
be found in section II.G.
Table III.E.1-17. Predicted percentile concentrations of individual OP pesticides
and of the cumulative OP distribution in the Midsouth Region.
;«;'• '-',45f^
••'•ChemlcafW
Acephate
Chlorpyrifos
Dicrotophos
Dimethoate
Disulfoton
Malathion
Methamidophos
Methyl Parathion
Phorate
Profenofos
Phostebupirim
Terbufos
Tributes
*l^ f* X 1
•*ppti«v>rop/
Cotton
Corn
Cotton
Corn, Cotton
Cotton
Cotton
Cotton
Cotton, Soybeans
Cotton
Cotton
Corn
Corn
Cotton
OP Cumulative Concentration (in ppb
methamidoDhos eauivalents)
*MaH!!
4.66+00
3.7e-02
1.5e+00
2.16-01
1.3e-02
1.4e+01
7.2e-01
1.56-01
5.66-01
1.86-01
3.66-02
1.06+00
3.3e-01
8.76+00
7.46-01
1.66-02
6.3e-01
6.1e-02
1.1e-02
1.8e+00
8.1e-02
8.16-02
8.7e-02
2.76-02
1.56-02
3.56-01
2.2e-01
4.36+00
1.1e-01
7.0e-03
2.9e-01
1.3e-02
6.4e-03
4.2e-01
7.7e-03
4.4e-02
4.2e-03
3.8e-03
7.3e-03
1.2e-01
1.7e:01
1.96+00
2.8e-02
3.9e-03
1.4e-01
6.36-03
4.9e-03
2.56-01
1 ,0e-03
2.36-02
1.16-04
9.76-04
4.56-03
6.86-02
1.26-01
1.06+00
1 .6e-03
1.8e-03
4.76-02
1.36-03
3.16-03
8.56-02
1 .2e-05
1.06-02
8.96-08
9.16-05
2.56-03
2.16-02
7.66-02
4.46-01
2.26-04
1.3e-03
2.7e-02
4.66-04
2.76-03
5.06-02
6.86-07
6.7e-03
1.56-09
3.06-05
2.16-03
1.26-02
6.6e-02
3.16-01
3.96-07
5.3e-04
9.76-04
I.Oe-05
1.3e-03
1.56-03
8.46-09
1.76-04
3.66-15
3.36-07
9.56-04
4.96-04
4.46-02
4.16-02
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i. Comparison of Monitoring Data versus Model Estimates
The maximum detect from the USGS NAWQA Mississippi Embayment
study unit for chlorpyrifos was an order of magnitude greater than the
maximum estimated concentration. The estimated maximum concentration is
roughly equivalent to the 90th percentile concentration in the monitoring data.
The maximum detect for methyl parathion in NAWQA was four times greater
than the maximum estimated concentration. The estimated peak
concentration falls somewhere between the 95th and 99th percentile of
monitoring data. The maximum detect for disulfoton in NAWQA was an order
of magnitude greater than the estimated maximum concentration, which was
less than the analytical limit of detection (LOD) for disulfoton in the USGS
study. On the other side, the maximum estimated concentration for malathion
was an order of magnitude greater than the highest NAWQA detection, which
fell between the 95th and 99th percentile in the estimated distribution.
While dicrotophos was not included in the NAWQA study, it was included
in an earlier USGS study on cotton pesticides in the Mississippi Embayment
(USGS Fact Sheet 022-98; Thurman et al, 1998. Available from the web site
http://ks.water.usgs.gov/Kansas/pubs/fact-sheets/fs.022-98.html).
Dicrotophos was detected in 35% of the samples (a comparison of the
dicrotophos LOD of 0.016 ug/L to the estimated concentration distribution
I.E.1 Page 53
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shows an equivalent percentage above the LOD). The maximum detection
reported for dicrotophos corresponds to the estimated 90th to 95th percentiles.
The Bogue Phalia River near Leland, MS contained the most detections
and co-occurrences. Malathion, methyl parathion, and chlopyrifos were all
detected in the Bogue Phalia River, but chlorpyrifos was only detected twice.
For malathion (Figure III.E.1-10), both estimated and observed concentrations
were consistent except for the highest percentiles. For methyl parathion
(Figure III.E.1-11), the observed concentrations were higher than estimated
starting about the 80th percentile.
Estimated
i Bogue Phalia River
40 60 80
Percentile
100 120
Figure 111.E.1-10. Comparison of observed and estimated malathion concentrations
in the Mid-South Region.
o
O
Estimated
Bogue Phalia River
40 60 80
Percentile
100 120
I Figure III.E.1-11. Comparison of observed and estimated methyl parathion
| concentrations in the Mid-South Region.
I.E.1 Page 54
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I ii. Summary of NAWQA Monitoring Data in the Region
I The Mississippi Embayment NAWQA study unit extends from northeast
| Louisiana along the Mississippi River as it forms the borders of Mississippi,
I Arkansas, Tennessee and Missouri. The USGS description of the region
C\l I states that 62% is used for agriculture, up to 90% in areas of intensive row-
. O [ crop agriculture. About 94% of drinking water supplies in this study unit were
^ 1 derived from ground water in 1 995 (USGS Circular 1 208).
— i
i None of the nine active OPs included as analytes were detected in ground
I water studies in this study unit. Surface-water sampling resulted in the
| detection of multiple OPs. Sampling programs included three agricultural
| streams, one mixed use stream, and one urban stream sampled at least
- | biweekly for two years. In addition, 38 sites from "streams that drained all
J*f I major crop types grown in the Study Unit" were sampled once each (USGS
£ I Circular 1208).
co !
CO I Diazinon and chlorpyrifos were detected in 96% and 100% of urban stream
CD 1 samples, respectively. They were detected in 4% and 6% of agricultural
CO I stream samples. Malathion was detected in 56% of urban, 36% of mixed use,
I and 1 1 % of agricultural samples, with a maximum concentration of 0.61 6 ug/l
I (agricultural).
CO I Other OPs were detected in surface water as well. Methyl-parathion was
| detected in 10% of samples, with a maximum concentration of 0.422 ug/l.
I Azinphos-methyl was detected in 5 samples, with a maximum detected
0 | concentration of 1 .0 ug/l. Disulfoton was detected in three samples, with a
i> I maximum detection of 0.213 ug/l. Phorate was detected once at 0.2, ethoprop
+-* ! once at 0.206 ug/l, and terbufos twice, with a maximum concentration of 0.173
TC I ug/l.
Z5 I .
1 The U.S. Geological Survey (USGS) Organic Geochemistry Research
| Group (OGRG) designed a cotton pesticide monitoring study, the results of
i which are published as the May 1998 USGS Fact Sheet 022-98, "Occurrence
| of Cotton Pesticides in Surface Water of the Mississippi Embayment." The
| OGRG collected weekly samples at 8 fixed sites, and collected single samples
I at another 56 sites in 1996.
I Seven different OPs were detected in this study above a detection limit of
O I °-01 U97'
CO I (http://ks.water.usgs.goV/Kansas/pubs/fact-sheets/fs.022-98.fig.8.gif).
> I Dicrotophos was detected in 35% of samples, methyl parathion in 18%, and
0 | profenofos and malathion in 12%. Sulprofos, chlorpyrifos and azinphos-methyl
I were a'so detected: The 90th percentile concentration detected for all OPs was
[ 0.3 ug/l or less.
I.E.1 Page 55
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The high rate of detection in this study correlates to high use of these OPs
on cotton. Methyl parathion, profenofos and dicrotophos are applied
extensively to cotton. The OGRG reported that although profenofos was used
three times as much as dicrotophos, dicrotophos was much more frequently
detected. This is consistent with the shorter persistence of profenofos.
Table III. E. 1-1 8. Magnitude and Frequency of Occurrence of OP Pesticides
Analyzed in the NAWQA Study Units in the Mid-South Region.
Land «
Use - •"
Value
• :.ifi>;ij
S'*1^ t *
isa **"**
ita* ¥J~* X
chlorpyrifos
•tH<',:i«l
diazinon
disulfoton
ethoprop
> * * *; "
malathion
a.1" W- -
azinphos
methyl
methyl
parathio
n
phorate
terbufos
'••!,}; ., ,<•',,,, . : .^Concentation (ug/L)
Mississippi Embayment
All
Locations
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
Agriculture
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.251
0.134
0.041
0.019
0.005
0.004
0.004
13.2%
1.050
0.376
0.125
0.010
0.003
0.002
0.002
14.3%
0.200
0.049
0.010
0.004
0.004
0.004
0.004
5.2%
0.020
0.017
0.005
0.002
0.002
0.002
0.002
4.2%
0.213
0.021
0.021
0.017
0.017
0.017
0.017
0.9%
0.206
0.005
0.005
0.003
0.003
0.003
0.003
0.3%
0.616
0.488
0.147
0.047
0.017.
0.012
0.005
26.2%
0.071
0.021
0.017
0.017
0.017
0.017
0.017
0.9%
0.005
0.005
0.003
0.003
0.003
0.003
0.003
0.0%
0.616
0.311
0.062
0.020
0.005
0.005
0.005
15.6%
1.000
0.521
0.146
0.050
0.001
0.001
0.001
1.5%
0.422
0.274
0.082
0.022
0.006
0.006
0.006
10.1%
0.0654
0.500
0.106
0.020
0.001
0.001
0.001
0.5%
0.422
0.285
0.108
0.044
0.006
0.006
0.006
10.4%
0.244
0.011
0.011
0.002
0.002
0.002
0.002
0.3%
0.011
0.011
0.002
0.002
0.002
0.002
0.002
0.0%
0.173
0.017
0.017
0.013
0.013
0.013
0.013
0.6%
0.017
0.017
0.013
0.013
0.013
0.013
0.013
0.0%
Urban
Mixed
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.251
0.223
0.133
0.089
0.077
0.069
0.036
92.9%
Maximum
99th
95th
90th
80th
75th
50th
Frequenc
y
0.186
0.052
0.011
0.005
0.004
0.004
0.004
7.5%
1.050
0.897
0.451
0.380
0.342
0.319
0.154
96.4%
0.242
0.042
0.010
0.006
0.004
0.002
0.002
12.9%
0.021
0.021
0.020
0.017
0.017
0.017
0.017
0.0%
0.005
0.005
0.004
0.003
0.003
0.003
0.003
0.0%
0.560
0.511
0.334
0.173
0.072
0.050
0.012
57.1%
0.213
0.036
0.021
0.020
0.017
0.017
0.017
1.1%
0.206
0.021
0.005
0.005
0.003
0.003
0.003
1.1%
0.560
0.526
0.217
0.095
0.027
0.024
0.005
41.9%
0.0427
0.0427
0.048
0.018
0.001
0.001
0.001
3.7%
0.061
0.058
0.035
0.006
0.006
0.006
0.006
7.1%
0.011
0.011
0.008
0.002
0.002
0.002
0.002
0.0%
0.900
0.630
0.300
0.120
0.050
0.029
0.001
3.3%
0.312
0.126
0.055
0.020
0.006
0.006
0.006
10.8%
0.244
0.030
0.011
0.009
0.002
0.002
0.002
1.1%
0.017
0.016
0.013
0.013
0.013
0.013
0.013
3.6%
0.173
0.029
0.017
0.017
0.013
0.013
0.013
1.1%
I.E.1 Page 56
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Appendices
E. Water Appendix
2. Summary of State Monitoring Programs
The EPA Office of Pesticide Programs (OPP) contacted State Lead Pesticide
Agencies in October and November, 2001 to inquire whether OP insecticides
were included in ground-water or surface-water monitoring programs over the
last decade. When monitoring programs were performed by agencies other than
the Lead Pesticide Agency, these were contacted, as well. If OP monitoring data
were available for a particular state, OPP inquired whether the data were
available over the Internet. Many State Agencies offered to provide data if
information has not yet been made available online.
The majority of State monitoring programs included few OPs in their analysis,
if any. The majority of States have focused monitoring efforts on ground-water
monitoring, including monitoring of five herbicides under the Pesticide
Management Plan. With few exceptions, such as California's program to
evaluate the effect of OP dormant spray applications on surface-water quality,
= State monitoring programs have not specifically been targeted to the areas and
i timing of OP application. Because of this, and because OPs are not yet required
I by the Safe Water Act to be included as analytes in drinking water sampling,
(/) | data from State monitoring programs are used as important supplemental data
| for the OP cumulative drinking-water risk assessment.
01 a. Alabama
> f
*-" | Tony Gofer, Pesticide Administrator of the Alabama Department of
2«J I Agriculture and Industry Groundwater Protection Section, reports that OPs
;3 | have not been included in joint sampling with the Alabama Department of
CI | Environmental Management. If analysis using immunoassay methods
IZ I indicated detections of pesticides above 1 ppb, a full gas chromatography
1 scan was done. In addition, a full scan was performed every 10 samples.
| Dr. Enid Probst of the Alabama Department of Environmental
I Management does not recall if OPs were ever detected. However, no more
| than 1 % of samples taken in the program had detections of pesticides other
| than those in the Pesticide Management Plan. This could be due in part to
0 1 the detection limits used by the State Agricultural Lab earlier in the program.
CO ! If OPs were detected at any point, it was not because of systematic, targeted
> I monitoring in OP use areas.
0 I
I b. Alaska
I Rose Lombardi of the Department of Environmental Conservation
1 Pesticide Program reported that Alaska does not look for OPs in drinking
! III.E.2 Page 1
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o I
-— i d. Arkansas
CD
i
e. California
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CDPR has seen measurable improvements in the samples they have
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water. The pesticide program has done some outreach by offering domestic
well testing, mostly for 2,4-D.
c. Arizona
The Agency has not obtained monitoring data from the State of Arizona.
Charles Armstrong, Assistant Director of the Arkansas State Plant Board
reported that Arkansas has detected a few herbicides in ongoing ground-
water monitoring since 1992, but no OPs.
The California Environmental Protection Agency Department of Pesticide
Regulation (CDPR) performed a 10-year study of rice pesticides in surface
water, which included methyl parathion and malathion. CDPR samples the
Colusa Basin Drain, an agricultural discharge channel that collects outflow
from rice fields from about 20 to 100 miles north of Sacramento, and west of
the Sacramento River. This area is used for many continuous miles of rice
monoculture on heavy clay soils.
According to the CDPR, methyl parathion was detected at concentrations
of up to 6 ppb in 1989. CDPR was concerned with surface water
contamination by a suite of.rice pesticides. By the late 1980s, CDPR had
instituted a control program to reduce the surface water impacts of rice
herbicides. In the early 1990s, the CDPR expanded the program to include
rice insecticides.
US I The program includes both irrigation and application controls to reduce
CZ | direct input of pesticides to the Colusa Basin Drain, which drains to the
-^ | Sacramento River. Rice farmers are required to hold water on flooded rice
Of fields for prescribed periods of time before releasing it to the drainage
I system, periods which depend on the pesticides applied. The holding time for
Q_ 1 methyl parathion is 24 days, but it is held longer if applied concurrently with
x-\ | another pesticide that must be held longer. A voluntary holding time of 4 days
is suggested for malathion. Application controls include requirements such
as positive shutoff systems for aircraft nozzles, use of drift control agents,
and a 300-foot buffer from water bodies for aerial applications.
taken each year from early or mid-April to mid-June. For instance, the peak
concentration of methyl parathion detected in 1996 was 0.12 ppb. A
maximum concentration of 0.107 ppb of methyl parathion was detected in 32
samples taken in 1997. A single detection of <0.1 ug/l of malathion was
I.E.2Page2
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• I been published, is a summary of about 30 monitoring studies, including
samples from the Sacramento and San Joaquin Rivers and their tributaries,
as well as agricultural drains. The monitoring was predominantly from
streams affected by agricultural runoff. Urban data is limited, but urban
concentrations were much higher.
' •
Agricultural loading was the most significant load of these chemicals in the
Sacramento River. Small streams in the Sacramento basin had the highest
f\ I agricultural detections. Of approximately 3900 individual samples for diazinon
Of a very small percentage exceeded the lifetime Health Advisory of 0.6 ppb in
| rivers and tributaries. None of the 3700 samples for chlorpyrifos had
~Q | concentrations that exceeded the lifetime Heath Advisory of 20 ppb. Overall,
0 | concentrations of chlorpyrifos were lower than those of diazinon. In general,
(/) I based on analysis which will be available when the paper is published, overall
"^ | concentrations in the winter application months have declined since a decade
I ago, corresponding with reductions in use (Frank Spurlock, personal
communication).
A prospective ground-water monitoring study for fenamiphos use on
grapes in California was begun in October, 1997, and preliminary information
III.E.2Page3
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I and monitoring results have been submitted in interim and.progress reports.
I , Interim reports indicate that fenamiphos and its sulfone and sulfoxide
| degradates were found in soil-pore water and ground, water after one
[ application of 6 Ib A.l./acre. Fenamiphos and fenamiphos sulfone were
\ detected in one ground-water sample, at concentrations of 0.05 and 0.53
CM I ppb respectively, 216 days after treatment (DAT). Fenamiphos sulfoxide was
O | detected in ground water samples from four of eight well clusters, at
^H I concentrations up to 2.13 ppb. These concentrations can be considered as a
T_ | lower bound measure of the peak concentrations of total fenamiphos
| residues in ground water resulting from use of fenamiphos on HSG A soils, It
| is likely that application to similar soils in areas with higher rainfall or at higher
i = applications rates will result in higher groundwater concentrations. A similar
-* I study on more vulnerable soils in the Florida Central Ridge resulted in
£- I significantly higher ground-water detections.
£ I The California Department of Pesticide Regulation is currently sampling
00 | "about 40 domestic wells for fenamiphos in high use areas" (Robert
00 | Matzner, CDPR, written communication to EPA). Twenty-eight wells sampled
CD 1 in 2001 did not have detections of fenamiphos, fenamiphos sulfoxide, or
I fenamiphos sulfone. This sampling program is ongoing! These OPs were also
1 not detected in 803 wells sampled in California from 1985 to 1994.
•3
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is
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V 1 California has a ground-water monitoring database required under their
00 1 Pesticide Contamination Prevention Act that includes data since 1984. No
I OPs are among the pesticides California reports as having "verified"
I detections in more than 20,000 wells sampled since 1984.
CD ;
f. Colorado
Brad Austin of the Colorado Department of Health reported that diazinon
and malathion were detected in ground water one time each in 784 wells
since 1992. Chlorpyrifos and dimethoate were also included, but not detected
in monitoring.
g. Connecticut
CL I
Ol Judith Singer of the Connecticut Department of Environmental Protection
| Pesticide Management provided data from a USGS report which covers
monitoring of the Connecticut, Housatonic and Thames Rivers from 1969 to
1992. This report indicates that diazinon was detected in 3 surface water
samples from 0.01 to 0.03 ppb (although a detection limit of 10 ppb was
reported). Chlorpyrifos, diazinon, and phorate were detected once each at
0.01 ppb, and a single detection of "total diazinon" occurred at 0.07 ppb.
Connecticut's main focus for ground-water monitoring is the Pesticide
Management Plan (PMP). ,
I.E.2Page4
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1 h. Delaware
| Scott Blaier, a hydrologist with the Delaware Department of Agriculture,
| indicated that chlorpyrifos was detected one year in domestic and monitoring
| wells. As part of the PMP program, chlorpyrifos was included in 1998. The
C\l I top of the well screen of 70% of the "domestic and agricultural wells" sampled
O f was between 16 and 35 feet. Top of screen for 80 percent of the monitoring
^Hl | wells was shallower than 15 feet.
T"""" i
1 Chlorpyrifos was detected in a single well (LOD = 0.22 ppb) at a
I concentration of 0.75 ppb. This was a domestic well screened between 33
| and 38 feet. Details of the monitoring program are available in "The
1 Occurrence and Distribution of Several Agricultural Pesticides in Delaware's
*— I Shallow Ground Water", 2000: http://www.udel.edu/das/pub/RI61.pdf
0 I
i i. Florida
(/) | Keith Parmer of the Florida Department of Agriculture and Consumer
0 | Services provided results of three ground-water monitoring programs (plus
I data from an additional background well network) which included OPs as
| analytes. Seventeen OPs and transformation products are included as
I analytes among these three studies:
(/) | azinphos-methyl, chlorpyrifos, diazinon, dichlorvos, disulfoton, ethion,
| ethoprop, fenamiphos, fenamiphos sulfone, fenamiphos sulfoxide, malathion,
I methamidophos, methyl parathion, methyl paraoxon, naled, phorate and
d) I terbufos.
> \
"***-* | The three studies include both monitoring and drinking water-supply wells:
| The Florida Department of Environmental Protection and the Florida
I Department of Health in which "up to 50 private drinking water wells were
| selected from each of Florida's 67 counties, to be sampled for a fairly
| comprehensive list of ground water contaminants. As of 1998, wells from
| approximately 26 counties had been sampled. The extent to which the
ry | selected wells represent either the private drinking water resource or the
| ground water resource is unknown" (Keith Parmer, personal communication).
| This data set includes 7016 "determinations" for OP insecticides.
0 | "Determinations" are the total number of analyses made for OPs, including
(/) | duplicates and split samples. No OPs were detected in these samples
> 1 "without qualifiers."
0 1
\ The second dataset included results from the "Very Intense Study Area
I Network." There have been 22 VISA studies to date, "with 7-45 well/spring
[ stations located in each VISA. VISA sample stations were deliberately
{ located to fall within particular land use/vulnerability domains; the water
! III.E.2Page5
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quality in these areas may very likely be impacted by human activities" (Keith
Parmer, personal communication). No OP was detected in 12,136
determinations for OPs in this data set.
A follow-up monitoring program to that performed by the FDEP and the
FDEH include private and public drinking water supply wells. This dataset
includes 7411 determinations for OPs. Fenamiphos sulfoxide was detected in
five samples in 2 wells from this study in 1992 and 1993. The maximum
concentration detected in both wells was 1 ug/l.
Mr. Parmer reported that a "Lake Wells Ridge monitoring network"
included shallow ground-water samples analyzed for OPs. He related that
other compounds have been detected in this study, but not OPs.
j. Georgia
, Doug Jones of the Department of Agriculture indicated that GDA has a
Pesticide Monitoring Network in conjunction with the Georgia Geological
Survey. This ground-water monitoring program includes annual sampling of a
wide number of pesticides, including OPs included in EPA method 507.
Before 1999, NAWQA monitoring wells were included in the program.
Recently, GDA has limited sampling to domestic wells, and excluded
monitoring wells. Sampling has been mostly in southern, agricultural portion
of state, which includes recharge areas for the Floridan aquifer. Wells in the
program are located where the water table is shallower than 100 feet.
Reports from the last three years indicate that no OPs were detected in
samples from this network. Previous studies indicate that no pesticides were
detected above MCLs; OP insecticides have not yet been assigned MCLs.
k. Hawaii
«= Robert Boesch of the Department of Agriculture Pesticides Branch
described a drinking-water study conducted in March, 2001. In preparation for
the OP risk assessment, Hawaii sampled 36 drinking-water wells in areas
where OPs are used on pineapples, or for urban use. These water supply
wells, which have shown contamination for other organic chemicals, did not
have detections (LOD 0.5 ppb) of the following OPs:
acephate, azinphos methyl, chlorpyrifos, DDVP, demeton, diazinon,
dimethoate, disulfoton, ethoprop, fenamiphos, malathion, metnidation, methyl
parathion, mevinphos, monocrotophos, naled and parathion.
I. Idaho
I.E.2Page6
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Gary Bahr of the Idaho Dept of Agriculture Division of Agricultural
Technology indicated that Idaho tests for OPs on a routine basis. There have
been occasional, rare detections of diazinon and methidathion.
m. Illinois
CM
Dave McMillan of the Illinois Environmental Protection Agency Bureau of
Water's Ground Water Section indicated that Illinois has focused ground-
water monitoring on herbicides since 1993, due to reduced funding. The
Illinois Source Water Protection Program, which will lead to assessment of
the State's community and non-community water supplies, does not include
OPs. Ambient lake monitoring done by the State also does not include OPs.
n. Indiana
Ryan McDuffee, an Environmental Scientist with of the Indiana
(/) | Department of Environmental Management Office of Water Quality sent data
CO | sets of pesticides detected in surface water during their 5 year "Surface
0 1 Water Quality Assessment Program." The program has tested for 226
V% I pesticides and semi-volatile compounds using EPA methods 525.5 and 547.
The first of these methods includes many OPs. Three years of data are
available, and Mr. McDuffee provided spreadsheets of detections in these
three years. Only one OP, stirofos, was detected in the three years of
CO 1 sampling.
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1 997- Stirofos, a cattle OP detected at 0.1 ppb in 898 records of stream-
water detections.
> | Q 1998- No OPs detected in 1416 records of stream-water detections
P I Q 1999- No OPs detected in 563 records of stream-water detections
03 f
33 ' 1 Al Lao of the Indiana Department of Environmental Management
indicated that OPs are not included in surface-water or ground-water drinking
~: | water analyses, as they are not required to be by the Safe Drinking Water
-"* s Art
O
o. Iowa
Mary Skopec, Acting Section Supervisor of the Iowa Department of
Natural Resources' Water Monitoring Section, reports that "Iowa's ambient
water monitoring program was expanded in 1999 in response to increased
appropriations from the State. Prior to 1999, very little state money was
spent on money and nearly all ambient monitoring was paid for by EPA.
Therefore our monitoring program was constructed to provide basic
information (water chemistry and nutrients). Since 1999, we have been
working to expand the number of sites and the types of analyses conducted
as part of our monitoring program. Due to the severe restrictions in funding,
OPs were not very often included in the monitoring programs."
III.E.2Page7
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1 Chlorpyrifos, ethoprop, fonofos, phorate, terbufos, dimethoate, diazinon,
| malathion, and parathion were included in Iowa's Statewide Rural Well-Water
| Study. This study included 686 private wells sampled once during 1988-89,
| with 10% of the private wells repeat-sampled during 1990 and 1991. None of
[ the OPs were detected in this study. After the conclusion of the SWRL study,
CNI I private wells continued to be monitored as part of Iowa's Grants to Counties
O I program, but not for pesticides.
| Iowa has a cooperative program with the USGS to sample 90 municipal
I wells on a four-year cycle. Iowa samples 45 wells in surficial materials
[ (alluvial and Pleistocene) each year; bedrock wells are cycled in based on
i j vulnerability to contamination. Twenty-two "vulnerable" wells are sampled
*-» | every two years, and 23 "protected" wells are sampled every 4 years. OPs
C | are not included in this monitoring.
C I i- Future ground-water monitoring
I Iowa's Ambient Surface Water Monitoring program has included about
"43 | 80 sites (including 23 up/downstream of 10 major cities)in two years of
_CD | sampling. Sampling during the first year included two analyses for OPs
-^ I (Fall of 1 999 and Spring of 2000), and samples in the second year were
| collected and analyzed for OP insecticides during April, May, June, and
| July, 2001 . Only one detection of parathion and two detections of
- | chlorpyrifos have occurred since 1999. Concentrations detected were low,
\-s | in the 0.05 ppb range. In 2002, Iowa will sample and analyze for OP
f\ | insecticides during April, May, June, and July.
I p. Kansas
0| Theresa Hodges of the Kansas Department of Health and Environment
(yj | reports that of the OPs, only diazinon has been detected in their routine
•;TJ | ambient surface water quality sampling network. While diazinon is not on the
\ 1 list of pesticides routinely included, it was added because it had been
| detected. Since 1995, 44 detections were found at 16 urban or golf course
I sites. The range of detections was from 0.1 9 to 1 .5 micrograms/liter.
I.E.2 Page 8
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Dale Lambley, Special Environmental Assistant to the Secretary of the
Kansas Department of Agriculture sent information on their ground-water
monitoring of chemigation wells. The objective of the study "is to assess and
monitor groundwater quality by obtaining water samples at selected
chemigation sites located at agricultural irrigation wells." In sampling from
1987 to 2000, chlorpyrifos was detected three times at concentrations of 1.9,
3.5 and 4.2 ppb (LOD = 0.5 ug/l). Dimethoate, disulfoton and methyl
parathion were included in sampling, but were not detected above detection
levels of 2.0, 0.5 and 1.0 ug/l, respectively.
The 100 samples taken annually are apportioned among five
I Groundwater Management Districts based on the number of registered
| chemigation sites in each. Highest priority is given to finding active
I chemigation sites. Ranking of wells has also been based on proximity to
[ public water supplies (within 3 miles), depth to water, soil type, and whether
| chemigation misuse is suspected.
CO
q. Kentucky
Peter Goodman of the Kentucky Division of Water reports that the
following OPs are included in their ground-water monitoring program:
acephate, chlorpyrifos, diazinon, disulfoton, ethoprop, malathion, methyl
parathion and terbufos. Each was included in more than 1300 analyses from
over 300 wells, but only diazinon, chlorpyrifos and malathion were detected.
Chemical # Wells # Samples # Detections Max. Cone.
Diazinon 362 1809 10 0.17 ppb
Chlorpyrifos 398 2057 7 7.1 ppb
Malathion 364 1821 2 0.32 ppb
r. Louisiana
Karen Irion indicated that it is very unlikely that Louisiana would have
analyzed drinking water for OPs, since they have not been required up to now
by the Safe Drinking Water Act.
s. Maine
0 | Julie Chizmas, Senior Water Quality Specialist of the Maine Department
I °f Agriculture Board of Pesticides Control wrote that Maine samples drinking
| water wells no more than 1/4-mile down-gradient of an active pesticide use
I site. Analytes are chosen based on local sales data. Sampling took place in
i 1994 and then in 1999, and included the following OPs:
f III.E.2Page9
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I azinphos methyl, chlorpyrifos, diazinon, ethoprop and phosmet.
| No OPs were detected in 1999. One detection of diazinon in 1994 (7.4
| ppb) was determined to be the result of a homeowner putting diazinon around
i her well head to get rid of ants. Ethoprop was detected in one well at 0.075
CM I ppb. No followup to that detection was conducted.
Of
[ Surface-water monitoring in Mane has included the following OPs:
I
i azinphos methyl, chlorpyrifos, diazinon, ethoprop, malathion and
| phosmet.
I
[ Most surface-water monitoring in Maine is in response to the endangered
I species designation for Atlantic salmon. "Blueberries are the most intensively
| grown commodity in the salmon watershed." Only phosmet has been
I • detected to date in surface water, with a maximum detection of 0.52 ppb (3
(/) | detections). In this study, surface water samples were collected less than 2
(/) I hours after a phosmet application. Sampling continues in that watershed,
CD I except for ethoprop.
C/) I
2 I t. Maryland
Rob Hofstedter of the Maryland Department of Agriculture reports that
C/) i their agency has a current ground-water study that includes diazinon. Results
of this study are not yet available. He referred me to the Maryland Geological
Survey for information on previous surface-water studies which included
d) I malathion.
> I
"-i—» I David Bolton of the Maryland Geological Survey provided summary tables
CD I from the MGS Report of Investigations number 66, "Ground-Water Quality in
33 ' I the Piedmont Region of Baltimore County, Maryland." Analysis in this rural
C3 ( region included 12 OPs, 10 of which are still registered. Seven of the 10
*~ I current OPs were not detected in ground water. Results of the monitoring are
J~? I as follows, which concentrations in ug/l.
n i Pesticide # samples MRL >/=MRL /=MRL
0
0
1
0
0
1
0
0
0
1
1
-------
[ Terbufos 112 0.013 0 0
I MRL = Minimum Reporting Limit
i Surface-water sampling at 8 sites at the Pocomoke River in 1998 did not
CM | result in detections of chlorpyrifos, dimethoate, malathion or terbufos above
O I levels of detection. One sample included a "trace" level of terbufos, reported
I as between 0.07 and 0.1 ppb.
i u. Massachusetts
CO i
i | Kenneth Pelotiere of the Massachusetts Department of Environmental
-*-« | Protection Source Water Assessment Program indicated that over the last 10
C | years, testing of surface water and ground water has been for pesticides
| required under the Safe Drinking Water Act. Therefore, OPs have not been
I included as analytes.
c/) i
(/) i v. Michigan
0 I
( | Dennis Bush from the Surface Water Quality Division has sent information
\ on a study of tributaries of the Saginaw River, which included OPs as
I analytes. The Agency has not yet reviewed this data.
(/) | Mark Breithart of the MDEQ Drinking Water Division examined their
database, and found that analysis was done for the following OPs in Michigan
drinking water:
CD
> | azinphos methyl, chlorpyrifos, .diazinon, dimethoate, disulfoton, fenamiphos,
I malathion, methyl parathion
i
I None of these were detected in 49 analyses of public water supplies. Of the
| 421 analyses from private water supplies, only dimethoate was detected. This
[ single detection of 2 micrograms/liter occurred at an aerial spray service, and
i therefore it is not clear if it was the result of a point source.
| w. Minnesota
| Daniel Helwig reported that the Minnesota Pollution Control Agency does
I not have ground-water monitoring data for insecticides.
CD I
(/) I Mark Zabel of the Minnesota Department of Agriculture reported that OPs
^> I are not included on the list of pesticides included in surface-water and
0 I ground-water monitoring. Although pesticides are added if they are identified
in anomalous gas-chromatpgraphy peaks, he cannot recall any OPs being so
identified.
x. Mississippi
III. E.2 Page 11
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Rusty Crowe reported that the Mississippi Department of Agriculture and
Commerce Bureau of Plant Industry has not conducted ground-water
monitoring since performing an atrazine study in the mid-1990s.
Shedd Landreth of the Mississippi Department of Environmental Quality
reports that about 125 wells a year are included in the Mississippi Agricultural
Chemical Ground-Water Monitoring Program. This program, which is funded
by user fees, concentrates on existing shallower wells, including drinking
wells and irrigation wells, and is patterned after the EPA's National Pesticide
Survey.
A number of OPs are included in their analytical method. However, if other
peaks are found in GC analysis, they are identified. Since 1989 through
present, 910 wells in the state have been sampled, concentrating in areas of
pesticide usage. Out of 910, chlorpyrifos was detected in 3 wells, with a
concentration range of 0.002 to 0.22 ug/l. Diazinon was detected in one well
early in the study at a concentration reported as "trace".
Profenofos was detected in three samples collected from center-pivot
irrigation system. Mr. Landreth collected these samples himself, and noted at
the time that he believed the samples had suffered from cross contamination
from the irrigation equipment itself, resulting from application the day before.
Resampling the next day resulted in non-detections.
CO
Malathion was also detected in one well. Mr. Landreth suspects this may
also have been external contamination, because malathion was being aerially
applied in area.
y. Missouri
Paul Andre, Program Coordinator of the Department of Agriculture Plant
Industries Division indicated that the Department of Natural Resources
undertakes water monitoring. Terry Timmons of the Department of Natural
Resources explained that they sample surface water and ground water used
as drinking water, and analyze for pesticides using several EPA methods.
n | However, although method 507 can include OPs, Missouri does not include
.r-v I them among the analytes.
-Q [ John Ford from the Department of Natural Resources sent 1997 to 1999
0 | stream-water monitoring data from their Water Pollution Control Program for
(/) I diazinon, chlorpyrifos and malathion. Results from the fixed-station database
"5> i are as follows:
0 I
diazinon: 124 detections in 330 samples, range 0.001 to 0.976 ppb;
chlorpyrifos: 50 detections in 328 samples, range 0.001 to 0.691 ppb;
malathion: 36 detections in 223 samples, range 0.004 to 0.325 ppb.
I.E.2Page12
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z. Montana
Donna Rise of the Montana Department of Agriculture (MDA) Agricultural
Sciences Division Technical Services Bureau reports that the MDA samples
ground water for pesticides generally, although the Department of
Environmental Quality undertakes monitoring on a "project or issue basis".
The State has specific criteria under which to put pesticides in a
"Groundwater Management Plan". The only current management plan is for
imazamethabenz methyl.
Montana currently has a network of 14 shallow wells throughout the state,
which are <50 feet deep, "most between 13 and 35 feet." These wells are
sampled twice a year, in the spring before application, and in the fall post-
harvest. Analytes are chosen based on use. In addition, a "Domestic Rural
Monitoring Program" took place from 1992 to 1995, and included two
domestic wells in each county.
CO
There was a single detection of malathion in a 35-foot well drilled into "a
CD j cobbly or gravelly loam." The detection was at a concentration of 4.8 ppb in
May 1999. A sample from the same well in June was estimated at 0.017 ppb
(LOQ = 0.4), and there was no detection in July, October or December.
Although this was a very vulnerable well, there also had been a dirt-floor
_y | storage shed 10 feet unpradient of the well three years before. MDA is not
CO 1 certain that the single detection reflected normal agricultural use.
f? i
*-*~ = aa. Nebraska
Craig Romary of the Nebraska Department of Agriculture Bureau of Plant
Industry indicated that Nebraska maintains the "Quality-Assessed Agricultural
Contminant Database for Nebraska Ground Water," which was created from
ground water quality data submitted by many organizations." The following
OPs are included in the database:
Chlorpyrifos- No detections in 3936 aalyses.
Diazinon- No detections in 190 analyses.
Disulfoton- No detections in 185 analyses.
Ethion- No detection in 1 analysis.
Malathion- No detections in 31 analyses.
Methyl parathion- No detections in 3679 analyses.
Phorate- No detections in 182 analyses.
Terbufos- No detections in 4729 analyses.
The levels of detection are generally below 1 ppb.
Mr. John Lund, supervisor in the Surface Water Unit of the Nebraska
Department of Environmental Quality, indicated that OPs have not been
included in the State's surface-water monitoring.
III.E.2 Page 13
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bb. Nevada
Scott Cichowlaz reported that malathion, diazinon and guthion were
found at low levels in some ground-water monitoring studies. Perhaps 200
shallow wells that are 10 to about 90 feet deep are included in this study.
These include monitoring wells installed by the State, NAWQA wells, and
water authority wells. Each year a subset of 50 to 70 wells is sampled.
Nevada has monitored all agricultural uses in the State, and looked only at
active products, used in the areas where they are looking.
In most cases sampling was from drinking water wells, some of which are
perforated pipe from surface down. The State hasn't found pesticides in the
drinking water wells.
cc. New Hampshire
The New Hampshire Department of Environmental Services does not
include the OPs in drinking water analysis. The state does not include OPs in
systematic ground-water monitoring, which is focused on the Pesticide
Management Plan program. Pat Bickford of the NHDES indicates that some
monitoring of OPs has occurred, but only when the Department of Agriculture
investigating misuse for enforcement, or rarely at the request of a
homeowner.
\ dd. New Jersey
CD I •
> I Dr. Roy Meyer of the New Jersey Department of Environmental Protection
"->-* I (NJDEP) Pesticide Monitoring and Evaluation group indicated that NJDEP
J3 | has not detected OPs in its ground-water monitoring program. The wells in
3 | this program are mostly concentrated in the agricultural areas of southern
C | New Jersey. The wells are shallow (<30 feet), and are intended to give a
= I sense of pesticide migration through the vadose zone.
Another program is in place for the Pesticide Management Plans.
ee. New Mexico
The surface water program in New Mexico monitors stream samples over
a 5 year cycle. The program is done in order to meet requirements of the
Total Maximum Daily Load program. The State attempts to look at more
extreme conditions, such as storm-water or low-flow conditions. The State
runs the EPA method 8270, which includes many OPs.
I.E.2 Page 14
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Before 1998, all of their data were entered into STORET (21-NEX is their
STORET code). The State is attempting to move to an ACCESS- based
database, but this'more recent data is not entered yet.
ff. New York
CM
O Jeff Myers of the New York Department of Environmental Conservation
Bureau of Technical Support says that the emphasis in New York is bottom
sediments and fish tissue, with little sampling in the water column. This
sampling has concentrated more on organochlorines, although some less
persistent pesticides have recently been included.
gg. North Carolina
Dr. Henry Wade, Environmental Programs Manager of the North
CarolinaDepartment of Agriculture and Consumer Services described the
CO "Interagency Study of the Impact of Pesticide Use on Ground Water in North
CO Carolina," which took place between 1991 and 1995. Sampling of mostly
CD shallow monitoring wells was performed based on information by farmers on
which pesticides they used within 300 feet of the wells. By the end of the
^ study, more than 240 pesticides were included as analytes.
j^ [ Sixteen OPs were included in the analysis, but none were detected. The
CO I number of wells sampled for each OP is shown below:
nx I
acephate (23 wells), azinphos-methyl (7), chlorpyrifos (25), diazinon (8),
0 dimethoate (5), disulfoton (12), ethoprop (6), fenamiphos (4), fonofos (1),
> malathion (9), mevinphos (1), parathion (5), phorate (3), phosmet (2),
terbufos (13) and trichlorfon (2).
. Other pesticides were detected in these wells, especially herbicides. The
main focus of the study was herbicides which the EPA had identified as
"potential leachers."
A separate study of domestic wells resulted in a single detection of
n diazinon at 0.55 ppb. It is not clear if this was the result of domestic use.
O hh. North Dakota
"O
0 Bill Schuh of the North Dakota State Water Commission described the
CO ground-water monitoring program run by the ND Department of Health. About
150 to 200 wells are sampled each year, and OPs are included among the
0 analytes. More vulnerable aquifers are sampled on a one square-mile grid,
ry* with a bias toward shallow wells. This sampling occurs once every five years,
and annual reports are available since 1992.
I.E.2Page15
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Norene Bartelson of the NDDoH provided further information. In its
"Ambient Groundwater Monitoring Program," the NDDoH has collected
"approximately 2,700 samples from 1465 wells." This program includes five
OPs: chlorpyrifos, diazinon, ethyl parathion, methyl parathion and malathion.
There have been OP detections in six wells over that time:
Well # Date Sampled
15105504AAA 6/23/93
9/29/93
15305532AAA 6/23/93
6/23/93
5/11/94
5/04/99
5/04/99
9/21/99
7/11/00
1/30/01
7/18/01
9/13/01
6/26/01
9/11/01
I 13705228CAA
I 14708011CAA
I 1541011 SAAB
I 16305620BDC
Analyte
Ethyl Parathion
None
Ethyl Parathion
Ethyl Parathion
None
Malathion
Malathion
None
Malathion
None
None
Malathion
None
Diazinon
Concentration
1.833ug/l
0.274 "
0.322 "
0.379"
0.460 "
0.171"
0.340 "
0.100 "
Sample Type
Regular
Regular
Regular
Duplicate
Regular
Regular
Duplicate
Regular
Regular
Regular
Regular
Regular
Regular
Regular
ii. Ohio
Only chemicals with MCLs are included in Ohio water monitoring
programs, and therefore no OP insecticides (Todd Kelleher and Julie
Letterhos, Ohio Environmental Protection Agency, personal communication).
The "Ohio EPA Pesticide Special Study," a 4-year study which examined
pesticides which might be found in finished drinking water, also did not
include OPs.
OPs are not part of routine sampling, although Ohio does some
watershed-specific monitoring (Gail Hess, OEPA, personal communication).
Data collected through 1998 could be extracted from STORET, but anything
since then isn't yet electronically available. Several OPs may have been
included. The Agency will evaluate the data in the STORET database.
The Great Lakes represent a significant drinking water supply, but water
monitoring of the lakes has not concentrated on OP contamination. According
to the State of Ohio's State of the Lake Report, for instance, 31 water-
treatment plants on the north shore of Ohio draw water from Lake Erie
http://www.epa.state.oh.us/oleo/leqi/14.pdf. These systems have not
analyzed for OPs to this point, as such analysis was not required by the Safe
Drinking Water Act.
These systems are likely to look for triazines once a month in the summer,
and quarterly otherwise. Ohio EPA undertook a "pesticide special study"
I.E.2Page16
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I between 1995 and 1999, but also looked only for herbicides
1 (http://www.epa.state.oh.us/ddagw/pestspst.html ). Cities like Cleveland and
1 Toledo get their water from intakes a couple of miles into Lake Erie.
| Therefore, they rarely detect pesticides other than small levels of atrazine at
| times. Smaller communities might have their intakes somewhat closer to
CM | shore (Todd Kelleher, Ohio EPA Dept. of Drinking and Ground Waters,
O | personal communication).
x__ | jj. Oklahoma
\ Don Molnar of the Oklahoma Department of Agriculture Plant Industry and
| Consumer Services Division indicated that the Pesticide Management Plan is
1 the major monitoring effort currently underway in Oklahoma. While that
[ program does not include the OPs, Oklahoma is performing a general
I "OP/OC" screen for a study monitoring irrigation tailwater from containerized
I nurseries, and in wells for their Organic Certification program. The data is not
(/) | in an electronic format that would permit quick extraction of OP analyses. The
CO I specialized nature of these monitoring programs would limit the usefulness of
CD I the data for the cumulative risk assessment, in any case.
tf) I
I kk. Oregon
V I The Agency has not obtained monitoring data from the State of Oregon.
CO I
\ "• Pennsylvania
CD | John Pari of the Pennsylvania Department of Agriculture Bureau of Plant
> I Industry indicated that Pennsylvania has ground-water monitoring programs
I that are tailored to particular crops uses. This includes a program focusing on
I corn that has run from 1995 to the present. The wells are described as "water
I supply" wells, whether as sources for drinking water for humans or livestock.
I
I Chlorpyrifos is the only OP included in this analysis. There have been
\ about 450 analyses to date, and chlorpyrifos was detected in "4 or 5"
| samples. The maximum concentration detected was 0.29 ppb. Another study
n 1 is just beginning in orchard areas, and may include other OPs.
mm. Rhode Island
"0 1
0 1 Eugene Pepper of the Rhode Island Department of Environmental
CO I Management Division of Agriculture and Resource Marketing reports that in
"> | addition to required Safe Drinking Water Act analyses, the Department of
Q) | Health uses Method 525 to analyze ground water and surface water for
1 chlorpyrifos, diazinon, and by special request, malathion. However, these
I insecticides have not been detected. Mr. Pepper pointed out that both raw
| and finished water are tested, but the lab does not include the transformation
I products in the analysis.
[ III. E.2 Page 17
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I A nearly completed ground-water study for turf chemicals includes
| chlorpyrifos, but chlorpyrifos has not been detected in this study, either.
| nn. South Carolina
CNI | Jerry Moore of Clemson University said that South Carolina has not
O | detected OPs in ground water. South Carolina monitors about 150 rural wells
| (domestic supply, irrigation, shop wells) per year, and runs a broad GC
| screen. The analysis focuses on 22 pesticides, none of which are OPs.
1 Therefore, the detection limit may be a little higher for pesticides other than
i . the main 22. This program has been ongoing since 1990.
|
I Peter Stone of the Department of Health and Environmental Control
| reports that South Carolina does not routinely analyze drinking water for
[ anything but those required by the Safe Drinking Water Act. Kathy Stecker of
1 the SCDHEC provided the internet address for the list of pesticides included
(/) | in the State's ambient surface-water monitoring program (
(/) I http://www.scdhec.net/eqc/water/pubs/appd.pdf). OPs are not included in
CD 1 that list.
(f) |
= oo. South Dakota
V | Brad Berven of the South Dakota Department of Agriculture Pesticide
(/) 1 Program reports that the South Dakota "Statewide Ground Water Quality
| Network" was sampled between 1989 and 1997. This statewide program was
| meant to monitor "shallow, sensitive aquifers" in the state for non-point
Q) 1 agricultural contamination. Monitoring wells were sampled for a number of
> I chemicals, including pesticides. The wells were generally sampled once per
*•*-* [ year, although wells with pesticide detections were subsequently sampled
fl3 | four times per year. One aquifer (Big Souix) was sampled multiple times per
13 i year before 1994.
II [ This monitoring program included six OPs: chlorpyrifos, ethoprop, fonofos,
= parathion, phorate and terbufos. Fonofos and parathion are currently in the
1 process of voluntary cancellation. Chlorpyrifos was not detected in 231
o | analyses. Ethoprop was not detected in 160 analyses. Phorate was not
X-N I detected in 230 analyses. Terbufos was not detected in 246 analyses.
"Q I pp. Tennessee
0 I
(/) i Ken Nafe of the Tennessee Department of Agriculture repprts that, "We
"+£ | have found some chlorpyrifos is ground water in several wells. The primary
I source is from termite treatments that followed the supply line into the well
= and then went down the well casing. We have worked with Dow to clean up
| all wells successfully."
I.E.2Page18
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Mr. Nafe also provided a surface-water monitoring database, which
included chlorpyrifos as the only OP in sampling from 1996 to 2001.
Chlorpyrifos was not detected in ambient samples, nor in raw or finished
drinking water samples.
qq. Texas
The USGS conducted a study of cotton pesticides in playa lakes in the
High Plains of west Texas. Dicrotophos was detected in one sample of 32.
The study authors indicate that the lack of OP detections could be due to the
general short half-lives of these insecticides, but could also be due to
sampling that may have occurred before the application of the OPs that
season.
® rr. Utah
fc
Mark Quilter of the Utah Department of Agriculture and Food directed the
(/) 1 Agency to a web page describing their private well monitoring network:
CD I
tO 1 http://ag.utah.gov/mktcons/groundwater.htm
(/) I
CD
i
| Mr. Quilter reported that Utah has not detected any insecticides in five
| years of sampling, and that a single detection of 2,4-D in a sump well is the
(/) [ only detection in the program to date.
| Arne Hulquist of the Utah Department of Environmental Quality reported
0 I that their data through 2001 is on STORET, but that they have had few
> | positive pesticide detections.
_ 1 ss. Vermont
13 1
I Gary Giguere of the Vermont Department of Agriculture, Food and
I Markets reports that OPs are not regularly included in their monitoring, but
I that the State has an OP screen. This is used for enforcement cases,
• I generally. OPs are not included in drinking-water monitoring.
o. i
Of Surface-water monitoring is not only for corn herbicides, but also railroad
f program, golf course permitting (includes some OPs). Act 250 requires a
-Q [ detailed pesticide management plan to protect surface and ground water.
0 | They have a list of pre-screened pesticides, and the state monitors certain
C/5 I courses. The courses must monitor drinking water. State monitors surface
"•> | water, in order to be sure that permitting is effective in protecting water
0 I resources.
S
1 In 1999, VDAFM analyzed turf (including lawns and golf courses)
I pesticides in streams adjacent to a residential complex immediately following
I a commercial landscape application. Diazinon, chlorpyrifos and malathion
I III.E.2 Page 19
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were included in the analysis. Of these, only diazinon was detected (2
samples), at concentrations of 0.08 and 0.22 ppb.
tt. Virginia
Marvin Lawson of the Virginia Department of Agriculture and Consumer
Services indicated that Virginia undertook a ground-water monitoring study
from the mid- to late-1990s. Daniel Schweitzer of VDACS reported that this
study did not include OPs. He is unaware of any Virginia ground-water or
surface-water monitoring program that included the OPs as analytes.
uu. Washington
The Agency has not obtained monitoring data from the State of
I Washington.
CO vv. West Virginia
CO
Doug Hudson of the West Virginia Department of Agriculture says that
West Virginia DoA does intermittent ground water sampling, including an OP
screen. He could recall only a single detection of diazinon, which they could
not confirm. Other OP detections in ground water were in response to
improper termiticide use.
co ;
~ry \ Chad Board of the West Virginia Department of Environmental Protection
I sent a spreadsheet with analytical results which included the following.OPs:
0 | chloropyrifos, diazinon, disulfoton, ethoprop, malathion, phorate, and
> I terbufos. Each were sampled in 12 wells, but not detected. The detection
"-*-• 1 limits ranged from 0.005 to 0.027 ppb.
CO I
ww. Wisconsin
Bill Phelps, of the Wisconsin Department of Natural Resources Bureau of
Drinking & Groundwater provided a summary of monitoring Wisconsin has
done in public and private water supply wells and information on monitoring
from their GEMS database performed at regulated/investigated sites.
I.E.2Page20
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Csl
o
Analyte
chlorpyrifos
diazinon
DDVP
dimethoate
disulfoton
malathion
methyl
parathion
phorate
# Water
Supply Wells
1
12
8
0
1
1
54
# Detects in
Water Supply
Wells
0
0
0
0
0
0
#GEMS wells
0
20
20
127
190
20
166
199
# GEMS wells
with
detections
9
0
0
9
5
0
21
Maximum
concentration
detected (ug/l)
420
240
19
37
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xx. Wyoming
Jim Bigelow, manager of the Wyoming Department of Agriculture
Technical Services Department, described the generic Pesticide
Management Plan ground-water program, which includes a network of 178
wells. A total of 54 active ingredients are included as analytes, including eight
active OPs:
azinphos-methyl, chlorpyrifos, diazinon, disulfoton, malathion, methyl
parathion, phorate and terbufos.
Mr. Bigelow indicated that there have been detections of pesticides in 117 of
178 wells. The Agency will investigate further details of this program.
I.E.2Page21
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I III. Appendices
E
I
E. Water Appendix
3. Analysis of the USGS-EPA Pilot Reservoir Monitoring Program
Cxi [
O I a. Introduction
^*~., 8
x— i
T— | A pilot reservoir monitoring project initiated by the USEPA's Office of
Pesticide Programs (EFED/OPP) and Office of Ground Water and Drinking
Water (OGWDW), and USGS National Water Quality Assessment
(USGS/NAWQA) assessed pesticide concentrations in raw and finished
drinking water (Blomquist et al. 2001). Reservoirs were sampled because
they are important sources of drinking water and because they store runoff
water and pesticide loadings within their watersheds. Twelve water-supply
reservoirs (Figure III.E.3-1) and Community Water Systems (CWSs) were
selected based on general vulnerability for pesticide contamination.
Selection criteria included small watersheds with high pesticide use and high
runoff potential, representation across pesticide use areas, integration with
ongoing monitoring efforts, and feasibility of monitoring.
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Figure III.E.3-1: Location of Reservoirs in Pilot Monitoring Program
Samples from raw and treated (finished) drinking water and the reservoir
outflow provide an integrated water concentration for the reservoir watershed.
For each site visit, three samples were collected: 1) raw water from the intake
spigot of the public water system, 2) finished water from the compliance tap
at the entry point to the distribution center, and 3) ambient reservoir water
sample at the reservoir outlet. Samples were taken bi-weekly during the
period of intensive pesticide use, such as the post-pesticide application
season, and quarterly beyond the four- month post-application period. Two
I.E.3 Page 1
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sites were sampled at weekly intervals for six months after the application
season to improve the estimate of peak concentrations for short-lived
compounds. Raw and finished drinking water samples were taken at most
sampling times and analyzed using the USGS analytical schedules 2001,
9060, and 9002. Finished water samples were not quenched to eliminate
chemical oxidation from residual chlorine. Out of 186 pesticides and
degradation products analyzed, 46 were organophosphorus (OP) pesticides
and their degradation products (Table III.E.3.1).
Table III.E.3.1. Organophosphorus pesticides and
in the reservoir study, USGS Analytical Schedules
degradation products included
(2001 and 9002).
PESTICIDE
•Azinphos-methyl
Chlorpyrifos
Diazinon
Disulfoton
Ethoprop
Fonofos
Malathion
Parathion
Parathion-methyl
Phorate
Phosmet
Methidathion
(Supracide)
Profenofos
Sulprofos (Bolstar)
Terbufos
Dimethoate
IUPACNAME
S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-
ylmethyl) 0,O-dimethyl phosphorodithioate
O,0-diethyl-0-3,5,6-trichloro-2-pyridyl
phosphorothioate
0,0-diethyl-0-2-isopropyl
-6-methylpyrimidin-4-yl phosphorothioate
0,O-diethyl S-2-ethylthioethyl phosphoro-
dithioate
0-ethyl S,S-dipropyl phosphorodithioate
0-ethyl S-phenyl
(RS)-ethylphosphonodithioate
diethyl (dimethoxy-thiophpsphorylthio)
succinate
O,O-diethyl O-4-nitrophenyl phosphorothioate
O,0-dimethyl O-4-nitrophenyl
phosphorothioate
0,O-diethyl S-ethylthiomethyl phosphoro-
dithioate
0,0-dimethyl S-phthalimidomethyl
phosphorodithioate
S-2,3-dihydro-5-methoxy-2-oxo-1,3,4-thiadiazo
l.-3-ylmethyl 0,0-dimethyl phosphorodithioate
0-4-bromo-2-chlorophenyl O-ethyl S-propyl
phosphorothioate
0-ethyl 0-4-(methylthio)phenyl S-propyl
phosphorodithioate
S-tert-butylthiomethyl 0,O-diethyl -
phosphorodithioate
O,O-dimethyl S-methylcarbamoylmethyl
phosphorodithioate
DEGRADATES
Azinphos-methyl-oxon
Chlorpyrifos, oxygen analog
Disulfoton sulfone, Disulfoton sulfoxide
0-ethyl-O-methyl-S-
propylphosphorodithioate, Ethoprop
metabolite 76960
Fonofos, oxygen analog
Malaoxon
Paraoxon-ethyl
Paraoxon-methyl
Phorate oxygen analog
Phosmet oxon
Terbufos-O-analogue sulfon
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i
PESTICIDE
Ethion
Fenamiphos
Tebupirimphos
(phostebupirim)
Dicrotophos
fenthion
Isofenphos
Temephos
Tribufos
Propetamphos
Dichlorvos
Sulfotep
IUPAC NAME
0,0,O,O-tetraethyl S,S-methylene
bis(phosphorodithioate)
ethyl 4-methylthio-m-tolyl
isopropylphosphoramidate
3-dimethoxyphosphinoyloxy-N,N-dimethylisocr
otonamide
0,0-dimethyl O-4-methylthio-m-tolyl
phosphorothioate
O-ethyl O-2-isopropoxycarbonylphenyl
isopropylphosphoramidothioate
0,0,0,0-tetramethyl 0,O-thiodi-p-phenylene
diphosphorothioate
S,S,S-tributyl phosphorotrithioate
(E)-0-2-isopropoxycarbonyl-1-methylvinyl
O-methyl ethylphosphoramidothioate
2,2-dichlorovinyl dimethyl phosphate
0,0,0,0-tetraethyldithiopyrophosphate
DEGRADATES
Ethion monoxon
Fenamiphos sulfone, Fenamiphos
sulfoxide
Tebupirimphos oxygen analog
Fenthion sulfone, Fenthion sulfoxide
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Ancillary data were also collected for each site to obtain information on
watershed properties, water treatment information, and reservoir
characteristics. The major cropping patterns in each reservoir watershed are
shown in Table III.E.3.2.
Table III.E.3.2: List of Major Crops in Watersheds of Selected Reservoirs in the
Reservoir Monitoring Stud;
State
MO
TX
OH
OK
CA
IN
SO
SC
NC
NY
PA
Cropping Pattern
Not available
Cotton
Corn / soybeans
Not available
Urban / Suburban
Corn / soybeans
Not available
Peach orchards
Tobacco, peanuts
Corn / soybeans
Corn / soybeans
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i b. Uncertainties and Limitations in Interpreting of Monitoring Data
| Some of the uncertainties and limitations associated with interpretation of <
[ the reservoir monitoring data are as follows:
CNJ | Q The samples are not truly paired because sampling did not account for
O i the travel time of the pesticide and its transformation products through the
T— | water treatment plant. This may limit stoichometric linkage of pesticide
T— | degradation and formation of degradation products during water
I treatment. However, comparisons of pesticide concentrations in raw and
| finished drinking water are possible because temporal variability of
i | pesticide concentrations is expected to be lower in drinking water derived
*-* | from reservoirs. Additionally, water samples were taken on the same time
*j^ | scale (hours) as the water treatment cycles for the water utilities.
El | Q OP pesticides had low recoveries in matrix-spiked finished water samples
(/) I (Personal Communication with Joel Blomquist, UGSG, April 28, 2000),
(/) | which may be associated with their low stability in finished water.
CD I Oxidative transformation products of OP pesticides, such as fenamiphos
[ sulfone and sulfoxide and tebupiriamphos oxygen analog, had higher
[ matrix spike recoveries in treated water than the parent compound.
[ Available data indicate OP compounds are not stable in chlorinated
V I drinking water (Magera, 1994, Tierney, et al. 2001, US EPA.2000).
(/) I Because OP pesticides generally have lower concentrations in finished
fy/ I water samples, the detection of any OP pesticide in finished water can be
I viewed as a reliable detection.
CD |
> i Q Ancillary data on weather, pesticide use, and watershed vulnerability need
"•*-» | to be considered when interpreting occurrence data. Sampling was
Cu | extended through 2000 because of extreme drought conditions in the
H3 | northeastern United States and California during the 1999 sampling
C | season. A lower than average rainfall may have impacted pesticide runoff
El | and resulted in fewer detections of pesticides.
>-' I c. Methods of Data Analysis
Q. I
O| Scientists in the Office of Pesticide Programs (OPP) of EPA analyzed the
I reservoir monitoring data for the organophosphorus compounds detected in
-Q I raw and treated waters. In this analysis, reservoir ("outfall") samples were not
0 | considered. Summary statistics were generated only for those OP
(/) | compounds in the cumulative OP assessment (Attachment III.E.1).
> \
0 1 Data from the USGS/EPA Reservoir Monitoring Study (Joel Blomquist,
/y I 6/11/01, Written Communication) were reformatted in an EXCEL
I spreadsheet to accommodate formatting requirements for Statistical Analysis
[ Systems (SAS is a Trademark of SAS Institude, Inc., Gary NC.). Sampling
| dates in the original data set were modified to facilitate translation of date
[ III.E.3Page4
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I variables. After the modification, EXCEL data sets for USGS schedules
1 2001, 9060, and 9002 were merged into a common data set using a SAS
I program. Working with USGS, EPA scientists conducted quality assurance
I and quality control (QA/QC) programs on the data set to eliminate replicated
! data or modified data. Each data analysis process is described below.
CSS [
O I i. Summary Statistics
I The Statistical Analysis Systems (SAS) procedures FREQ and
-^ I SUMMARY calculated detection frequencies and mean detectable
CO | concentrations. Concentration distributions (percentiles) were estimated
i I for OP compounds with 10 or more detections in a reservoir during 1999
| and 2000. Only diazinon and malaoxon met the criteria for percehtile
§ calculations. Percentiles were computed by two different methods for
1 evaluating non-detects. In Method 1 , the detection limit was used as a
I concentration measurement, while in Method 2, non-detects were set
(/) I equal to zero. This difference does not apply to the computation of mean
(/) | detected and maximum detected concentrations. Percentiles were
0 1 computed by linear interpolation using ©SAS proc univariate (percentile
C# I Definition 1). Ranked non-time weighted percentile concentrations were
I reported for all OP pesticides detected in raw or finished water samples
| (Blomquist et al., 2001). Annual time weighted mean (TWM)
\ concentrations were calculated for the OP pesticides using the limit of
(/) I detection (LOD) or zero for non-detections to provide bounding estimates
I of the TWM.
i ii. Considering the Impact of Water Treatment
I
| An analysis of water treatment effects was conducted by further
| modifying the merged data set to calculate the impact of water treatment
I on pesticide removal or transformation. In this analysis, all samples with
I nondetects in both raw and finished water samples were removed, while
I samples with at least one detection were retained in the database. For
1 those samples with one detection, the non-detection was modified to one-
| half the limit of detection (LOD). This data manipulation was required to
n | allow calculation of water treatment reduction percentages.
I Minimum, median and maximum water treatment reduction
I percentages were determined for paired raw and finished water samples
| for each pesticide. Water treatment reduction percentages were
(/) | estimated using the equation [(raw-finished/raw) *1 00]. These
•£ | percentages, though, can only be estimated when pesticides are detected
I in both raw and finished water samples. In this reservoir monitoring study,
I most organophosphorus insecticides were detected only in raw water
I samples or in finished water samples. In order to allow estimation of
I water treatment reduction factors, non-detections in raw or finished water
i samples were assumed to be equal to one-half the LOD. Negative
| III.E.3Page5
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values are calculated for samples where finished water concentrations
were higher than raw water concentrations. This situation can can occur
when detection limits or frequencies are low.
I d. Study Methods and Design
CsS [
O i i. Chemical Analytical Methods
i The reservoir study used three analytical methods: 2001 , 9002, and
i 9060. Method 2001 used a C-1 8 solid phase extraction and gas
= chromatography/ mass spectrometry (GC/MS) (Zaugg et al., 1995). This
| method has been approved and validated for use in the National Water .
| Quality Assessment (NAWQA) program. Methods 9002 and 9060 were
I under development and validation during the course of the study, but are
I now currently approved by USGS. Method 9002 (now referred to as
'! method 2002) used a C-1 8 solid phase extraction and GC/MS (Sandstrom
| extraction and high performance liquid chromatography/mass
CD | spectrometry (HPLC/MS) (Furlong etal., 2001). These methods were
95 i used to expand information on occurrence of pesticides and degradation
i products. Because methods 9002 and 9060 were under development
I and validated during the monitoring study, the data for these methods are
I considered as provisional by the USGS.
i ' ' '
\ ii- Quality Assurance and Quality Control Assessment
(D 1 As requested by OPP, USGS assessed quality assurance and quality
> I \ control (QA/QC) data for OP pesticides and their degradation products
*-* I (written communication from Blomquist, J. 5/17/02). The QA/QC
| assessment was conducted for method 2001 and the provisional method
= 9002 because these methods were used for chemical analysis of the OP
i pesticides. The QA/QC assessment is based on laboratory fortified
[ samples in reagent grade water samples and fortified matrix raw and
/T | finished drinking water samples. All pesticides were fortified in matrix
*~* [ samples at a concentration of 0.1 ug/L. The percent recoveries were
n I calculated by adjusting for actual sample volume and ambient
1 concentration of analyte in non-fortified samples.
-Q I The average analyte-matrix contact time was variable for the fortified
0 I matrix samples. In general, matrix samples for method 2001 were fortified
CO I in the field, shipped to the National Water Quality Laboratory (NWQL),
"^ I and then extracted within 1-7 days. The matrix samples for method 9002
0 1 were fortified at the NWQL. Recoveries from raw and finished waters were
| analyzed separately because of expected differences in matrix effects.
I Statistical analyses of analytical recoveries were conducted using a
1 parametric Cochran t-test or a non-parametric Kruskal-Walis test.
I.E.3 Page 6
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Mean analytical recovery of OP pesticides in fortified raw water matrix
samples ranged from 70% to 175% for 11 compounds for method 2001
and from 30% to 115% for 31 compounds for provisional method 9002
(Table III.E.3.3). Azinphos-methyl and disulfoton sulfone had the highest
mean analytical recoveries in raw water matrix samples. Dichlorvos had
the lowest mean analytical recovery in raw water matrix samples. Mean
analyte recoveries in finished water matrix samples ranged from 4% to
55% for method 2001 and 3% to 135% for provisional method 9002. •
Disulfoton and phorate oxon had the lowest mean analytical recovery in
finished water matrix samples, while tebupirimphos oxygen analog had
the highest mean analytical recovery in finished water samples.
Statistical analysis indicates median analytical recoveries in finished
water matrix were significantly lower than recoveries in raw matrix
samples for method 2001. A similar observation was found for 19
organphosphorus pesticides in method 9002. Diclorvos and
tebupiramphos, however, had significantly higher (P=0.05) median
recoveries in finished water when compared to raw water matrix samples.
Chlorpyrifos oxygen analog, fenamiphos sulfone, fenarniphos sulfoxide,
phosmet oxon, and terbufos-O-analogue sulfone had similar median
recoveries between raw water matrix samples and finished water matrix
samples.
Table III.E.3.3
OP pesticides
Mean recoveries of fortified laboratoy set and matrix samples for
from USGS methods 2001 and 9002 (decimal percentage).
Chemical
Azinphos methyl§
Azinphos-methyl-
oxon§
Chlorpyrifos§
Chlorpyrifos,
oxygen analog
Diazinon§
Diclorvos§
Dicrotophos
Dimethoate§
Disulfoton§
Disulfoton sulfone§
Disulfontone
sulfoxide§
Ethoprop§
Ethoprop
metabolite 76960§
Fenamiphos§
Lab Set 1999
0,81±0.39(108)
Lab Set 2000
0.86±0.34 (422)
0.48±0.20 (163)
0.90±0.14 (108)
0.90±0.1 0(422)
0.40±0.20(163)
0.91 ±0.1 5 (108)
0.93*0.11(422)
0.43*0.16 (163)
0.27±0.08 (163)
0.39±0.11 (163)
0.8310.18(108)
0.76±0.14 (422)
0.78±0.14(163)
1.12±0.35(163)
0.94±0.17(108)
0.86±0.13(422)
0.80±0.33 (28)
0.62±0.11 (163)
Raw Matrix : • ,
1.75*0.53(33)
0.85*0.29 (32)
1.00*0.28(34)
0.44*0.34 (32)
1.09*0.26(34)
0.30*0.22(34)
0.34*0.11 (30)
0.57*0.13(30)
0.70*0.30 (34)
1.06*0.24(32)
1.15*0.44(30)
1.07*0.26(34)
0.95*0.23 (32)
1.09*0.21 (30)
f FinisHed,MatnX>v / 'V>7?,
0.38*0.64 (30)
0.55*0.32(28)
0.21*0.35(31)
0.59*0.37 (28)
0.26*0.43(31)
0.46*0.24 (28)
0.30*0.14 (28)
0.05*0.15(28)
0.04*0.16(31)
0.15*0.33(28)
0.18*0.47(28)
0.55*0.41 (31)
0.80*0.33 (28)
0.04*0.20 (28)
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JcH^micaU ; • ' •
5*v*">^' .»*- - >-, * • '
Fenamiphos
sulfone
Fenamiphos
sulfoxide
Malaoxon
Malathion§
Methiadathion§
Paraoxon-methyl§
Parathion-methyl§
Phorate§
Phorate Oxygen-
Analog§
Phosmet
Phosmet Oxon
Tebupiriamphos§
Tebupiramphos
oxygen analog§
Terbufos§
Terbufos-O-
analogue sulfone
Tribuphos§
5fab>Set 199'9:-s' •, ;•,
Lab Set 2000 '. ;
0.63±0.17(163)
0.30±0.21 (163)
1.03±0.41 (28)
0.9510.19(108)
0.19±0.
0.9210.14 (422)
36 (28)
0.86±0.35(28)
0.8210.20(108)
0.79±0.14(108)
0.03±0.
0.07±0.
0.9510.14 (422) "
0.81±0.14(422)
15(28)
15(28)
0.49±0.43 (28)
0.1 9±0.
33 (28)
Not Available
0.80±0.15(108)
0.81±0.11 (422)
1 .07± 0.69 (28)
Not Available
Raw Matrix
1.12±0.27(30)
0.37±0.24 (30)
1 .0410.29 (32)
1.16±0.36(34)
1.15±0.31 (30)
0.79±0.26 (32)
1 .29±0.40 (34)
0.77±0.27 (34)
0.97±0.26 (32)
0.40±0.30(30)
0.37±0.30 (30)
0.98±0.10 (30)
1.0U0.22 (32)
0.8810.22 (34)
1.1210.65(30)
0.8510.12(30)
Finished Matrix
1.1310.46(28)
0.2710.27 (28)
1.0310.41(28)
0.1910.33(31)
' 0.1910.36(28)
0.8610.35 (28)
0.3110.52 (31)
0.0410.16(31)
0.0310.15(28)
0.0710.15(28)
0.4910.43(28)
0.1910.33(28)
1.3510.48(28)
0.0510.18(31)
1.0710.69(28)
0.5910.27 (28)
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( )- Number of samples used for mean and standard deviation
§- Indicates significant difference (P<0.05) in median recoveries from raw water and finished water samples
Azinphos-methyl had significantly (P=0.05) higher analytical recoveries
in raw water matrix samples than laboratory set samples (Table III.E.3.3).
Disulfoton had significantly (P=0.05) lower mean recoveries in raw water
matrjx samples compared to laboratory set samples. Raw water matrix-
enhanced recovery also was found for chlorpyrifos, diazinon, ethoprop,
malathion, parathion-methyl, and terbufos. Matrix enhanced'recoveries
have been found through quality control analysis for National Water
Quality Assessment Program (Martin, 1999).
i
Azinphos-methyl oxon and dicrotophos had significantly higher
(P<0.05) mean recoveries in raw water matrix sample compared to the
laboratory set recoveries, chlorpyrifos oxygen analog had significantly
higher (P=0.05) mean recoveries in finished water compared to laboratory
recoveries. There were no significant (P<0.05) differences in recoveries of
chlorpyrifos oxygen analog and disulfotone sulfoxide from raw matrix
samples and laboratory set samples.
In summary, the OP pesticides and their degradation products in the
cumulative OP assessment generally had similar or enhanced recovery in
I.E.3 PageS
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the matrix samples compared to the laboratory set samples. However,
parent OP pesticides had lower recoveries in finished water matrix
samples compared to laboratory set samples. OP degradation products
generally had similar or higher recoveries in finished water matrix
samples.
iii. Water Treatment Trains and Basic Water Quality Data
Although the water quality parameters, including pH, hardness, and
total organic carbon, varied among the 12 reservoirs (Table III.E.3.4), the
physical construct of the treatment train processes was similar.
Source Water =DScreens=£>Prechlorination (Preoxidation) =ORapid
Mixer=D>Flocculation=f>Filtration=&Post Disinfection^Clearwell
Table III.E.3.4: Average Water Quality Parameters for Raw Water at Candidate
Reservoirs
Water
Systems
MO
TX
OH
OK
CA
IN
SD
SC
NC
LA
NY
PA
Average Flow
Through Time
(hours)
26
10
23
NA
3.25
8.75
12-13
4
NA
NA
0.29
7-9
Water Quality Properties
pH
7.9 to 9.2
7.7
7.7
7.9-8.8
7.5
8.2
9.2
6.9
7
NA
7.8-9.0
7.2
Alkalinity (mg/L
as CaCO3)
63-120
100
95
137
91
128
32
17
12
NA
40-100
7.2
Hardness
(mg/L as CaCO,)
90 - 145
108
126
150
250
200
NA
15
NA
NA
140
172
TOC*
(mg/L)
4.7
4-8
5.2
5.8
6-8
4
NA
3.8
NA
NA
4.4
2-3
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NA-Not available
* TOC= Total Organic Carbon
The average water flow-through time at each treatment plant was less
than 24 hours. The most common treatment practices included
prechlorination and post disinfection, coagulation, and pH adjustment
processes. Chlorine and chlorine dioxide were the most common
disinfectants used in the prechlorination process (Table III.E.3.5), while
chlorine and chloramines were the most common disinfectants used in the
post disinfection process. The most common coagulants used in the
treatment trains were aluminum salts and polymers. The data also shows
I.E.3 Page 9
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I that pH was adjusted by adding lime and sodium hydroxide. Several of
| the treatment plants used activated carbon in the treatment train.
| . Powdered activated carbon was used as part of the pre-disinfection
| process in the PA, NY, SC, IN water utilities, while granular activated
I carbon was used prior to the post disinfection process at the MO, OK, and
| OH water utilities.
I Table III.E.3.5: Treatment trains for utilities in the reservoir monitoring program
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State
MO
TX
OH
OK
CA
IN
SD
SC
NC
NY
Treatment Train
(1) Prechlorination with Chlorine Dioxide -> (2) Flash Mixer +polymer coagulant -*(3)
Flocculation/Sedimentation + Lime -» (4)Flash Mixer + Sodium silica fluoride -*(5)
Flocculation/ Sedimentation + Chlorine ->(6) Dual Media Filtration + sand with GAC cap
(7) Chlorine added -»(8) Clearwell -> (9) Distribution
(1) Prechlorination with Chlorine + KMnO4 -»(2) Flocculation + Iron salts (ferric sulfate)/pH
adjustment (caustic soda) -> (3) Filtration- dual media sand/ anthracite ->(4) Post-
Disinfection with chloramines -* (5) Corrosion control- pH adjustment/ fluorisilic acid
1) Prechlorination with Chlorine Dioxide (CI02) + KMnQ4 -»(2) Rapid Mix + Aluminum
-> (3) Flocculation + pH adjustment/ polymers -* (4) Settling -*(5) Filtration (Rapid
sand with GAC) -* (6) Post-Disinfection (phosphate/ fluoride/chlorine and caustic soda) -
(7) Clearwell -> (8) Distribution
(1) Aeration -*(2) Prechlorination with ozone -*(3) Flocculating/ Clarifier + polymer/ Lime
->(4) Solids contact/ clarifier + carbon dioxide-* (5) Post-Disinfection with ozone-* (6)
Polyphosphate polymer + chlorine -> (7) Mixed media filters- multimedia-* (8) Carbon filter-
GAC-* (9) Post-Disinfection with chorine -*(10) Clearwell -* (11) Distribution
(1) Prechlorination with chlorine (optional)/ aluminum salts -> (2) Rapid Mix/ Cationic
polymer -> -»(3) Accelerator + chlorine (optional)/ non-ionic polymer -*(4) Pre-chlorination
+ NaOH-* (5) Dual media filters -*(6) Post-chlorination-> (7) Clearwell-* (8) Holding pond
(1) Prechlorination with chlorine + carbon and KMn04 -> (2) Splitter and Rapid Mix +
chlorine, aluminum sulfate, polylmer, carbon, ammonia, lime, and KMnO4 ->(3) Mixing and
settling basin + chlorine, polymer, and carbon added -*(4) Filter plant ->(5) Fluoride added
-*(6) Finished water reservoir + chlorine-* (7) Distribution
(1) GAC polymers -*(2) Lime, aluminum sulfate, polymers added->(3) Chlorine dioxide,
carbon dioxide, and fluoride added ->(4) Ammonium polyphosphate -»(5) Chlorine added
(1) Prechlorination with chlorine + liquid alum, lime, carbon, and polymer-* (2) Hydraulic
flocculators + aluminum salts, polymers ->(3) Dual media High Rate Filters -*(4) Post-
Disinfection with chlorine + fluoride, lime, and phosphate-* (5) Clean/veils-* (6) Distribution
pumps
(1) Prechlorination + aluminum salts and pre-caustic ->(2) Flash Mixer + polymer
Flocculator -* (3) Sedimentation basin + chlorine-* (4) Dual media filter ->(5) Post-
disinfection with chlorine + post caustic, fluoride, chlorine, and phosphate -*(6) Clearwell
-*(7) Distribution system
(1) Prechlorination with chlorine + KMn04/ PAC -* (2) Flocculation + aluminum salts/
polymers -*(3) Filtration - rapid sand and mixed media -* (4) Post-Disinfection with
chlorine + fluoride + ortho phosphate ->(5) Clearwell -»(6) Storage -»(7) Distribution
I.E.3Page10
-------
CM I
o i
State
PA
Treatment Train
(1) Prechlorination with chlorine dioxide + PAC + KMn04 + lime ->(2) Flocculation/
clarification + aluminum sulfate -» (S)Filtration with sand/ anthracite + hydrofluorisilicic acid
-» (3) Ammonium sulfate + chloramines -»(4) Corrosion control + phosphate -»(5) clean/veil
->(6) Reservoir ->(7) Distribution
c
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cr
The pilot reservoir monitoring study provided two years of raw (525
samples) and finished (249 samples) water occurrence data for 18 active OP
parent compounds and 13 transformation products considered in the
cumulative OP assessment. This pilot program included OP pesticides that
have not been analyzed in most other monitoring studies, such as tribufos,
phostebupirim, profenofos and dichlorvos, and some rarely analyzed
transformation products.
Of the thirteen OPs detected in either raw or finished drinking water
samples, diazinon was, by far, the most frequently detected compound.
Although it was found in 35% of 323 raw water samples (Table III.E.3.6), it
was not found in 227 finished water samples, suggesting that this pesticide
was reduced or transformed by water treatment processes. Unfortunately,
the likely transformation product, diazoxon, was not analyzed in the USGS
schedules to substantiate that it was found in treated water.
Other OPs and their oxygen analogs also followed a similar pattern of
detection, but the number of detections was not sufficient to formulate any
definite conclusions. For instance, malathion was detected in 6 of 323 raw
water samples (2%), while malaoxon was detected in 11 of 220 finished
water samples (5%). It is important to note that three finished and raw water
samples (LA water utility on August 26, 1999; September 8,1999 and June
7,2000) showed the presence of only malathion in raw water and malaoxon in
finished water. In this situation, malathion may have transformed into
malaoxon during the treatment process. Chlorpyrifos was detected in 5% of
raw water samples, but neither chlorpyrifos nor its oxygen analog were
detected in finished water. Azinphos-methyl and its oxon were both found in
raw and finished water. In this study, though, the difference between the
number of detections for each was not enough to allow statistical
quantification of treatment effects, especially since azinphos methyl and its
oxon were only found in the MO water utility.
Some non-persistent parent OP pesticides, such as fenamiphos and
disulfoton, were not detected in raw and treated water. However, their
longer-lived sulfoxide and sulfone transformation products were detected in
raw and finished water samples. The low detection frequencies (<1% or 2
samples) in raw and finished water samples limited a clear quantitative
assessment of treatment transformation.
I.E.3Page11
-------
Table III.E.3.6: Summary statistics for organophosphorus pesticides and their
degradation products
• • Y. Chemical
Azinphos-methyl-oxon
Azinphos-methyl
Chlorpyrifos
Chlorpyrifos, oxygen
analog
Diazinon
Diclorvos
Dicrotophos
Dimethoate
Disulfoton
Disulfoton sulfone
Disulfotone sulfoxide
Ethoprop
Ethoprop metasbolite
76960
Fenamiphos
Fenamiphos sulfone
Fenamiphos sulfoxide
Malaoxon
Malathion
Methidathion
Paraoxon-methyl
Parathion-methyl
Phorate
Phorate oxygen analog
Phosmet
Phosmet oxon
Profenofos
Tebupiriamphos
(Phostebupirim)
Terbufos-0-analog
sulfon \
Terbufos
Tribufos (DEF, s,s,s-Tr)
tebupiramphos oxygen
analoo
LOD1
0.031
0.001
0.004
0.016
0.002
0.005
0.016
0.005
0.017
0.005
0.016
0.003
0.005
0.016
0.008
0.031
0.016
0.005
0.008
0.031
0.006
0.002
0.031
0.008
0.016
0.008
0.016
0.016
0.013
0.016
0.008
Raw
No.
samples
316
321
323
316
323
316
316
316
323
316
316
323
316
316
316
316
316
323
316
316
323
323
316
316
316
316
316
316
323
316
316
No.
detects
1
8
17
114
4
1
1
1
2
6
1
1
3
% - -. •
Detected
0.3%
2.5%
5.3%
35%
1.3%
. 0.3%
0.3%
0.3%
0.6%
1.9%
0.3%
0.3%
•
0.9%
Max.
ug/L
0.263
0.144
0.034
0.101
0.022
0.013
0.006
0.005
0.033
0.106
0.01
0.061
0.007
Mean
ug/L
0.263
0.077
0.006
0.023
.'
0.012
0.013
0.006
0.005
0.021
0.032
0.01
0.061
0.005
Finished
No.
samples
219 •
225
227
220
227
220
220
220
227
220
220
227
220
220
220
220
220
227
220
220
227
227
220
220
220
220
220
220
227
220
220
No.
detects
4
5
.
2
1
11
1
2
%
Detected
1.8%
2.2%
0.9%
0.5%
5.0%
0.4%
0.9%
Max.
ug/L
0.026
0.114
.
.
0.016
0.022
0.556
0.001
0.015
Mean
ug/L
0.018
0.059
.
0.012
0.022
0.106
0.001
0.012
CM
O
CO
i
c
CD
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0)
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CO
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CD
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O
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0)
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CD
o:
(1) LOD = Limit of Detection. The value reported is the most common limit of detection. For some chemicals, the
LOD varied during method development.
Diazinon was detected in 10 of 12 reservoirs, and Chlorpyrifos was
detected in 6 reservoirs, reflecting their widespread use (Table III.E.3.7). The
maximum concentration of diazinon was 0.045 ug/L in the raw water of the
CA treatment plant. Percentile concentrations of diazinion for the combined
1999 and 2000 sampling season are shown in (Table III.E.3.8). The
distribution of diazinon concentrations in raw intake water suggest that the
detected concentrations of diazinon were roughly representative of percentile
concentrations greater than the 50th percentile. The estimated concentration
percentiles were relatively insensitive to the values assumed (either the
detection limit or zero) for non-detected samples.
I.E.3Page12
-------
i Table III.E.3.7: Summary statistics for water
/ear, and water utility
CM
O
CD
C
CD
E
V)
to
CD
0^|gUlUk^^^^H^H
Azinphos-methyl
Azinphos-methyl-
oxon
Chlorpyrifos
Diazinon
Dimethoate
Disulfoton sulfone
Disulfotone
sulfoxide
Fenamiphos
sulfone
Fenamiphos
sulfoxide
Malaoxon
Malathion
Methidathion
Parathion-methyl
Phorate
Terbufos-0-
analogue sulfon
tebupiramphos
(Phostebuoirim)
•
MO
SC
SC
MO
NY
OK
LA
MO
OH
OK
OK
PA
SC
CA
IN
IN
LA
MO
NC
OH
OH
OK
OK
PA
PA
SC
SC
TX
LA
PA
NY
NY
NC
NC
IN
IN
MO
LA
LA
LA
LA
MO
MO
LA
MO
PA
MO
•
2000
2000
2000
2000
2000
1999
1999
2000
2000
1999
2000
2000
2000
1999
1999
2000
2000
1999
1999
1999
2000
1999
2000
1999
2000
1999
2000
1999
1999
2000
2000
2000
1999
1999
2000
2000
2000
1999
2000
1999
2000
2000
1999
1999
2000
2000
1999
Raw
Finished
Raw
Finished
Finished
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Raw
Finished
Raw
Finished
Raw
Raw
Finished
Finished
Raw
Raw
Raw
Raw
Raw
Finished
Finished
Raw
PA 1999 Raw
|gm^|
1e
15
8
8
20
8
18
8
20
19
6
20
1
28
1
10
7
5
10
1
1
11
5
20
20
16
8
8
9
9
8
9
10
10
17
7
3
8
9
18
19
10
13
9
18
imEBii^
0.001-0.05
0.001-0.075
0.001-0.1
0.031
0.31-0.06
0.004-0.005
0.004
0.004
0.004-0.005
0.004-0.006
0.004-0.005
0.002
0.002-0.01
0.002
0.002-0.006
0.002-0.01
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002-0.005
0.002-0.006
0.005
0.005
0.005
0.016
0.008
0.008
0.031
0.031
0.031
0.016
0.016
0.005
0.005-0.027
0.005-0.027
0.008
0.006
0.002-0.01 1
0.016
0.008
HgBSMes
I
7
2
2
2
1
2
4
5
1
2
1
1
1
4
5
1
1
1
1
1
1
3
1
2
2
••^Hjg
0.034
0.019-0.114
0.029-0.144
0.008-0.01
0.026
0.002-0.004
0.002
0.003
0.002
0.003-0.004
0.005
0.003-0.004
0.003
0.002
0.002
0.001-0.003
0.003-0.004
0.006
0.006
0.007
0.005
0.022
0.008
0.008-0.01
0.001
0.009-0.015
0.003-0.007
|^aM|]KS
1
3
1
1
3
7
4
. 9
1
14
3
9
20
20
1
5
1
1
2
1
1
1
3
5
3
2
1
1
1
^^^^B^^^]
0.263
0.005-0.008
0.034
0.004
0.004-0.012
0.004-0.045
0.004-0.006
0.006-0.01
0.01
0.005-0.022
0.004-0.012
0.008-0.015
0.017-0.101
0.012-0.095
0.006
0.005-0.015
0.004
0.007
0.012-0.022
0.013
0.016
0.033
0.052-0.204
0.019-0.556
0.023-0.106
0.008-0.011
0.007
0.01
0.061
12 0.008 1 0.006
CO
o:
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O.
CL
O
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0
CO
a MMMMI
CD
OH
(1) Estimated concentrations are qualified estimate of concentration. This is defined as: Compounds with
low or high recoveries (for example, USGS analytical schedule 9002-outside the range of 60 to 120%
recovery ) or concentrations lower than the laboratory reporting limit.
III.E.3 Page 13
-------
I Table III.E.3.8: Concentration percentiles for diazinon in raw water samples
State
California
Indiana
Louisiana
Missouri
N. Carolina
New York
Ohio
Oklahoma
Penn..
S.Carolina
S.Dakota
Texas
No.
8
48
22
40
10
22
21
41
23
45
21 •
22
Detected
7
19
1
14
5
0
10
40
7
5
0 -
6
mean
(ug/L)
0.017
0.0059
0.010
0.0099
0.0068
0.0102
0.0505
0.0076
0.0018
0.0035
Percentiles (ug/L)
percentil max
e method 50th 75th 80th 90th 95th detected
(ug/L)
_,_ [not computed for <10 detections] . 0.045
"1 0.002" 0.005 0.0060 6.0082 0.0096 0.010
2 ^0.000 0.005 0.0054 0.0072 0.0090 _,
_j_ jnot computed "<10"detectionsL , 0.010
1 0~002 0".0060 0.0080 0.6l~1 0.0"13 0.022
2 0.000 0.0060 0.0070 0.011 0.013 _,
^ [not computed <10~d"etections] 0.012
\ | j
1 0.002 0.0088 0.011 0.013 0.013 0.015
2 _j_ 0.000 0.0088 0.011 0.013 0.013 ,
1 0".051 0.066 0.072 0.080 6.0~87 0.10
2 , 0.051 0.066 0.072 0.080 0.087 .
0.015
[not computed <1 0 detections] 0.0030
• 0.0040
CM
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CO
CO
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o:
Of the parent OP compounds, diazinon and chlorpyrifos were the only
ones^detected in more than three reservoirs while azinphos-methyl had the
highest detected concentration (0.114 ug/L in South Carolina raw water). It
also had a high detection frequency (32-46%) in raw and finished water
samples in the SC reservoir. Azinphos-methyl oxon was not detected in raw
or finished water from the SC reservoir. The precision of azinphos-methyl and
azinphos methyl-oxon concentrations, though, is low because the detections
were estimated at concentrations near the reported detection limit. Analytical
detection limits varied among the OP pesticides and their transformation
products (Attachment III.E.2). In general, the lowest detection limit was the
most commonly reported detection limit.
Malaoxon had the highest concentration of all 31 OP analytes, with
maximum finished-water concentrations in Louisiana of 0.556 ug/L in 2000,
and 0.204 ug/L in 1999. Malathion concentrations in raw water ranged from
0.023 to 0.106 ug/L in 1999 and 0.008 to 0.011 ug/L in 2000. The percentile
concentration of malaoxon in finished water at the LA treatment plant are
shown in Table III.E.3.9.
Table III.E.3.9: Concentration percentiles for malaoxon in finished water samples
in Louisiana.
Chemical ,' . >v - *, No'.
• ';>.•'••.'. ''/,»•;';'•• f">;;:«"'' rahalyzed'
-.'•• I't' ;';>?•: ''•*' '•.••"'"' :v-'-.v';> "
Malaoxon 21
(finished water)
Malathion 22
(raw water)
•No.;,: mean 50th
detects cone, %-ile
11 0.11 below
LOD
75th
' %-ile
0.052
5 0.038 [not computed with
80th 90th
%-ile %-ile
0.059 0.12
95th
%-ile
0.20
fewer than 10 detections]
range of
detected
cone.
0.008 -
0.56
0.008-
0.11.
I.E.3Page14
-------
CM
O
I Table III.E.3.10 summarizes percentile concentrations for the OP
I pesticides in raw and finished water. Malaoxon and diazinon were the only
I compounds with sufficient magnitude and range of detections to allow
| estimation of median, 90th percentile, and maximum concentrations. In most
I cases, maximum and 90th percentile concentrations were above the LOD
| while the 50th percentile concentration Was normally below the LOD.
| Table III.E.3.10: Concentration percentiles for OP compounds in raw and finished
water samples in (
Chemical
Azinphos-methyl
Azinphos-methyl-oxon
Chlorpyrifos
Diazinon
Dimethioate
Disulfoton sulfone
Disulfoton sulfoxide
Fenamiphos sulfone
Fenamiphos sulfoxide
Malaoxon
Malathion
Methidathion
Parathion-methyl
Phorate
Tebupiramphos
Terbufos-0-analogue
sulfone
ug/L).
iState
i
jSC
jSC
jNY
jOK
LA
jOH
jOK
•PA
'SC
OH
jOK
'PA
'SC
jTX
jCA
N
JLA
jMO
jNC
LA
jPA
jNY
NY
NC
JNC
jIN"
jMO
LA
LA
jMO
|MO
LA
MO
jMO
PA
jPA
!
jWater jMax
[Type j
jRaw j
jFinished j_
jRaw j
jRaw j_
[Raw |
[Raw j
jRaw j
jRaw '
i_ i
jRaw _j_
[Raw |
jRaw j
[Raw j
jRaw j
jRaw j
jRaw j
[Raw ]
[Raw |
[Raw [
jRaw j_
[Raw |
jRaw J_
jRaw j_
jRaw _j_
jRaw j
jFinished j_
jRaw j
jRaw j
jFinished '
jRaw j
jRaw j_
"Raw |
I |
"FinisTied '
"•Raw j
jRaw "
jFinished j
i i
3 ]90th p
i
0.144J
0.114j_
0~026j
0.263!
0".008j
0.004"
0.004"
0.015!
0.002"
0~615"
0.101"
0.012]
0.003!
0.004"
0.045!
0.01 j
0.01!
0.022J
0.012j_
0~007j
0.022j_
0".0i3j_
0~.6(f6!
0~005j
0.016!
0.033"
0.008'
0.556"
0~.iO~6j
0.007'
0.01 j
0.061J
____0_PP_1l
0.007j
0.006_[
0".015|
!
ercentile3 iMedian3 -^
i /.r-v :••-'
0.054J
0.038j_
0.013]
i
0.005"f
i
!
0.007]
j
0.013J
. 0.08!
0.004'
0.001'
0.004]
0.045!
O.OOSj
i
0.011!
0.01 1j_
I
0.006J_
i
i
0.002]
0.011J_
1
1
0.128j_
~0~.023j
i
1
I
+-— — _— - _ _.— _
______ — ___.
1
1
i
-'*4;^"
* H V
0.051
0.015
0.001
0.008
CD
0
E
CO
(/}
0
0)
"oo
0
CO
O
o.
O
"O
0
GO
">
0
cc
Percentile concentrations are taken from Blomquist et al., 2000.
Time-weighted mean concentrations (TWM) for OP pesticides and their
degradation products were low in raw and finished waters (Table III.E.11).
Diazinon had the highest TWM (0.059 ug/L) in raw water while malaoxon had
III.E.3 Page 15
-------
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O
CD
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13
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the highest TWM (0.043 ug/L) in finished water. In general, the bounding
estimates of TWM was dependent on the treatment of non-detections in the
calculation of TWM. The use of zero for non-detections led to TWM
concentrations below the LOD.
Table III.E.3.11: Time weighted annual means (TWM) for OP compounds in raw
and finished water samples in (ug/L).
OP
azinphos-methyl
azinphos-methyl-oxon
chlorpyrifos
diazinon
dimethioate
disulfoton sulfone
disulfoton sulfoxide
fenamiohos sulfone
fenamiphos sulfoxide
malaoxon
malathion
methidathion
parathion-methyl
State
SC
MO
NY
OK
LA
OH
OK
PA
SC
OH
OK
PA
SC
TX
CA
IN
LA
MO
NC
LA
PA
NY
NY '
NC
IN
MO
LA
LA
MO
MO
LA
Year
1999
2000
1999
2000
1999
. 2000
1999
2000
1999
2000
• 1999
2000
1999
2000
1999
2000
1999
2000
1999
2000
1999
2000
1999
2000
1999
2000
1999
1999
1999
2000
1999
2000
1999
2000
1999
1999
2000
1999
2000
1999
2000
1999
2000
1999
1999
2000
• 1999
2000
1999
2000
1999
2000
1999
2000
1999
2000
1999
Range
LOD
0.001-0.10
0.031-0.31
0.004-0.006
0.002 -0.01
0.005
0.005
0.008
0.031
0.016
0.005-0.027
0.008
. 0.006
Raw
TWM (DL)
.0.001
•.•-•••'• ; 0.051
0.031
0.031
0.031
0.031
0.035
0.032
0.006
( 0.005
0.004
0.004
0.004
0.004
0.004
0.005
0.004
0.004
0.002
0.009
0.055
0.059
0.002
0.004
0.002
0.003
0.002
0.030
bioos
0.006
0.002
0.004
0.005
0.002
0.003
0.004
0.005
0.005
0.006
0.016
0.016
0.005
0.005
0.008
0.031
0.031
0.031
0.025
0.013
0.016
0.016
0.010
6.005
07609
0.008
0.007
0.008
Raw
TWM(O)
0.000
0.017
0.000
0.000
0.000
0.000
0.005
0.000
0.004
0.000
0.000
0.001
0.000
0.000
0.000
0.002
0.000
0.000
0.000
0.008
0.055
0.059
0.001
0.003
0.000
0.000
0.001
0.030
0.001
0.006
0.000
0.000
0.003
0.000
0.002
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.000
0.000
0.000
0.000
0.012
0.001
0.000
0.001
0.000
0.000
0.002
Finished
TWM(DL)
0.001
0.029
0.024
0.024
0.031
0.031
0.013
0.021
0.004
0.004
0.004
0.002
0.002
0.003
0.004
0.004
0.003
0.003
0.002
0.002
0.001
0.002
0.002
0.003
0.002
0.002
. 0.001
0.002
0.002
0.003
0.002
0.002
0.002
0.002
0.002
0.005
0.005
0.005
0.005
0.016
0.016
0.005
0.005
0.008
0.024
0.031
0.024
0.020
0.032
0.043
0.005
0.009
0.004
0.008
0.006
0.005
0.006
Finished
TWM(O)
0.000
0.009
0.000
0.000
0.000
0.007
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.000
0.000
0.020
0.034
0.000
0.000
0.000
0.000
0.000
0.000
0.000
I.E.SPage 16
-------
CM
O
5
E
CO
V)
0
CO
CO
CO
CD
13
E
Z5
OP
phorate
tebupiramphos
terbufos-0-analogue
sulfone
State
MO
MO
PA
PA
Year
2000
1999
2000
1999
2000
1999
2000
1999
2000
Range
LOD
0.002-0.011
0.008
0.008
Raw
TWM(DL)
0.006
0.002
'*•' 0.003
0.008
0.007
0.007
0.008
.0.016
0.016
Raw
TWM(O)
0.000
0.000
0.000
0.000
0.000
0.002
0.000
0.000
0.000
Finished
TWM(DL)
0.006
0.002
0.003
0.006
0.005
0.008
0.008
0,016
0.016
Finished
TWM(O)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
*Shaded gray areas indicate TWM concentrations greater than the lowest LOD.
i. Water Treatment Effects
The concentration of most parent OP insecticides (diazinon,
chlorpyrifos, malathion, dimethiate, methyl parathion) fell below the LOD
during water treatment. Furthermore, the oxidative degradation products
(azinphos methyl-oxon, fenamiphos sulfoxide, malaoxon, and terbufos-O-
analogue sulfone) were detected more frequently in finished water than in
raw water. Several degradation products (malaoxon, and terbufos-O-
analogue sulfone) were not detected in raw water samples.
In analyzing the effects of water treatment on pesticide concentrations,
water treatment reduction percentages were used to quantify the water
treatment removal. These percentages, though, can be estimated only
when pesticides are detected in both raw and finished water samples
(Table III.E.3.12). In this reservoir monitoring study, most OP insecticides
were detected only in raw water samples or in finished water samples. In
order estimate of water treatment reduction factors, non-detections in raw
or finished water samples were assumed to be equal to one-half the
LOD. Negative values can occur when detection limits or frequencies are
low.
Table III.E.3.12: Water treatment reduction percentages and maximum
concentrations in raw and finished water for selected OP pesticides
Pesticide
Azinphos-methyl
Azinphos-
methyl-oxon
Chlorpyrifos
Diazinon
Dimethoate
Disulfoton
sulfone
uses
Schedule
2001
9002
2001
2001
9002
9002
Max Raw Cone
ug/L
0.144
0.263
0.012
0.101
0.022
0.013
Max Finish
Cone
ug/L
0.114
0.026
0.002
0.0025
0.0025
0.0025
Min Percent
Reduction
19
0*(-67)
0
0*(-150)
58
—
Max Percent
Reduction
41
94
83
99
88
80
O
"O
0
CO
0
I.E.3Page17
-------
CM
o
CD
C
0
E
(A
CO
0
co
CO
Pesticide
Disulfoton
sulfoxide
Fenamiphos
sulfone
Fenamiphos
sulfoxide
Malaoxon
Malathion
Parathion-
methyl
Phorate
Tebupiriamphos
Terbufos-0-
analogue
sulfone
USGS
Schedule
9002
9002
9002
9002
2001
2001
2001
9002
9002
Max Raw Cone
ug/L
0.006
0.005
0.033
0.008
0.106
0.061
0.001
0.007
0.008 .
Max Finish
Cone
ug/L
0.008
0.016
0.022
0.556
0.0025
0.003
0.001
0.004
0.015
Min Percent
Reduction
...
0*(-300)
...
0*(-6850)
64
...
• ...
33
0*(-87.5)
Max Percent
Reduction
0*(-33)
0*(-40)
33
0
97
95
0
42
0*(-12.5)
CO
CD
O
CL
O
"O
0
CO
">
0
DC
Equation for pesticide reduction calculation= (raw-finished/raw)*! 00
0* indicates a negative percent reduction was observed. A negative percent reduction indicates the
finished water concentration is greater than the raw water concentration.
-Indicates a single pair of raw and finished water was available.
Table III.E.3.9 shows a wide variability in the water treatment removal
efficiencies among organophospate compounds. Phosphorothioate and
phosphorodithiate compounds (chlorpyrifos, diazinon, parathion-methyl,
dimethoate) have high maximum water treatment removal percentages
(80-99%), while phorate and azinphos-methyl have lower water treatment
reduction percentages. These findings are consistent with those reported
in the open literature for chlorination effects on organophosphorus
insecticide degradation (Magera, 1994, Tierney, et al. 2001, US
EPA,2000).
The reservoir monitoring study shows, that in general, the oxidative
degradation products have lower water treatment reduction percentages
than their parent compounds. A negative water treatment reduction
percentage may indicate that the parent compound is transformed during
treatment. For some degradation products, such as malaoxon and
terbufos-O-analogue sulfone, chemical transformation is a possible
explanation for their occurrence in finished water samples only. For other
degradation products, such as azinphos-methyl-oxon, fenaminphos
sulfoxide, and fenaminphos sulfone, which were found in both raw and
finished water, degradate formation may occur during transport in the
watershed or water treatment.
I.E.3Page18
-------
CN
O
CD
C
0
E
V)
(/)
0
c/)
IT
0
_CQ
13
E
13
O
CL
O
0
C/)
">
0
tr
dMalaoxon
• Phorate .
• Disulfotone sulfoxide
QTerbufos-O-analogue sulfon
nFenamiphos sulfone
• Fenamiphos sulfoxide
QDisulfoton sulfone
• Malath ion
• Parath ion-methyl
• Azinphos-methyl
• Dimethoate
QChlorpyrifos
• Azinphos-methyl-oxon
DDiazinon
BJtebupiramphos (Phostebupir
Figure III.E.3.2: Maximum Water Treatment Reduction Percentages Among
Reservoirs
Figure III.E.3.2 shows the maximum water treatment reduction
efficiencies among the 12 reservoirs that were analyzed in this study.
Because individual treatment processes were not evaluated in this study
and detections were sporadic, it is difficult to assess the impact of specific
water treatment processes on pesticide removal and transformation.
Diazinon, which was detected most frequently in the raw water at 10
reservoirs, showed maximum water treatment reduction percentages,
ranging from 66-99% among the different water treatment systems.
Similar ranges of maximum water treatment reduction percentages were
reported for other organophosphorus pesticides. A possible explanation
for high water treatment removal efficiency is chemical oxidation to such
products as oxons through prechlorination and post-disinfection, which
are commonly used processes. Because the diazinon degradation
product, diazoxon, was not measured in this study, it is difficult to
evaluate any linkage between diazinon degradation and diazoxon
formation in finished water samples. However, there were three samples
in which malathion was found in raw water and malaoxon was found in
finished water at the LA water treatment plant (Figure III.E.3.3). This
observation may be explained by chemical oxidation as a result of
chlorination.
I.E.3Page19
-------
CNJ
o
CD
i
c
Q)
E
CO
c/)
0)
CD
C/)
0)
>
O
0.
O
"O
®
CO
">
CD
a:
August,1999
September, 1999
D June, 2000
Malathion-Raw Malaoxon-
Water Finished Water
Figure III.E.3.3: Malathion and malaoxon formation in raw and finish water
samples at the Louisiana water treatment plant
Another potential degradation pathway of organophosphorus
pesticides is base catalyzed hydrolysis through treatment by liming and
caustic soda. At this time, though, it is difficult to assess the impact of
hydrolysis on OP degradation pathways because information on pH and
contact time after pH adjustment were not available for the reservoir
monitoring study. In addition, hydrolysis degradation products were not
included on the USGS analytical schedules.
ii. Co-occurrence
Co-occurrence of organophosphorus pesticides was found in raw
drinking water but not in finished drinking water (Table III.E.13). Twelve
percent of the raw samples with OP detections (16 samples from 137
samples) had more than one OP detection. These data suggest that
water treatment processes may reduce the occurrence of parent OP
pesticides in finished drinking water.
Table III.E.3.13: Co-occurrence frequency of OP pesticides in raw and finish water
samples at reservoir water treatment plants
Number of OPs
,
sample
0
1 or more
1
2
3
Total
Number of samples (% of samples) with given number of OPs detected
Raw water
mples
177
137
121
12
4
314
%
56%
44%
39%
3.8%
1 .3%
100%
Fin
Samples
194
24
24
218
%
88.99%
11%
11%
100
Table III.E.3.14 shows the profile of individual co-occuring OP
pesticides and degradation products in raw water samples. These co-
occurring pesticides include azinphos-methyl oxon, azinphos-methyl,
chlorpyrifos, diazinon, dimethoate, fenamiphos sulfone, fenamiphos
I.E.3 Page 20
-------
CM
O
sulfoxide, methidathion, and tebupiriamphos, with diazinon co-occuring
the most frequently. These results also show that the PA and MO
reservoirs had the highest co-occurrences (3 pesticides per sample)
among the various reservoirs.
Table III.E.3.14: Co-occurrence profile of organophosphorus insecticides and
some transformation products
Sample
(State, date)
IN 7-1 1-2000
MO 5-17-1999
MO 5-24-1 999
MO 7-1 9-2000
MO 7-6-1 999
NC 5-25-1 999
OH 7-6-2000
OK 6-29-1 999
OK 7-6-1 999
OK 8-2-2000
PA 6-29-2000
PA 7-1 1-2000
PA 8-2-2000
SC 6-28-2000
SC 8-23-2000
SC 9-1 1-2000
Azi/oxon
0.263
Azinphos
E0.034
E0.042
E0.144
Chlorpyr
0.034
E0.002
E0.002
0.004
0.012
0.008
0.004
E0.002
Diazino
n
0.010
0.013
0.022
0.011
0.012
0.009
0.073
0.066
0.048
0.015
0.011
0.005
E0.001
E0.003
E0.002
Dirneth
0.022
0.012
E0.006
Fena/Sn
E0.005
Fen/Sx "*
0.033
E0.008
Methidat^
0.010
TebjjDira','
E0.007
E0.003
Explanation: E=estimated concentration. Azi/oxon=Azinphos-methyl oxon; Azinphos=Azinphos-
methyl; Chlorpyr(ifos); Dimeth(oate);Fena/Sn=Fenamiphos sulfone; Fen/Sx=Fenamiphos sulfoxide;
Methidat(hion);Tebupira(mphos)
CD
C
0)
to
(0
0
CO
CO
CO
0)
JCO
D
E
i3
O
O
-o
CD
CO
">
CD
cr
iii. Conclusion
The reservoir monitoring program provided significant information on the
occurrence of a wide range of OPs and their transformation products in raw
and treated drinking water. The magnitude of detectable concentrations and
frequency of detection of most OP compounds and degradation products
were generally low in raw and finished waters. Widely used compounds such
as chlorpyrifos.diazinon, azinphos methyl, and malathion were detected in
raw drinking waters, while degradation products of OP compounds were
predominantly found in finished drinking water. The maximum concentration
for OP pesticides in water was <0.5 ug/L. The magnitude of time weighted
mean (TWM) concentrations were generally similar to the limit of detection
(LOD) and highly dependent on the treatment of non-detections.
The reservoir monitoring data suggest that parent OP pesticides are
removed or transformed during treatment, possibly by chemical oxidation.
Oxidative degradation products of OP pesticides, such as sulfones,
sulfoxides, and oxons, were detected in certain finished water samples from
actual water treatment plants. At this time, the impact of the individual
treatment processes is difficult to assess because of variability among the
I.E.3 Page 21
-------
Csl
O
CD
C
CD
E
CO
CO
0)
CO
CO
CO
a:
0)
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E
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O
a.
O
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CO
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0
cr:
treatment plants in terms of water quality factors, sequence of treatment
operations, and dosage of applied treatment chemicals.
.E.3 Page 22
-------
Attachment III.E.1: 31 OP chemicals analyzed in the USGS Reservoir Monitoring
Study and Used in Analyses.
Chemical
CM
CO
c
0)
E
V)
0
C/)
0
to
1 Azinphos-methyl
2 Azinphos-methyl-oxon
3 Chlorpyrifos
4 Chlorpyrofos, oxygen analo
5 Diazinon
6 Diclorvos
7 Dicrotophos
8 Dimethoate
9 Disulfoton
10 Disulfoton sulfone
11 Disulfotone sulfoxide
12 Ethoprop
13 Ethoprop metasbolite 76960
14 Fenamiphos
15 Fenamiphos sulfone
16 Fenamiphos sulfoxide
17 Malaoxon
18 Malathion
19 Methidathion (Supracide)
20 Paraoxon-methyl
21 Parathion-methyl
22 Phorate
23 Phorate oxygen analog
24 Phosmet (Imidan)
25 Phosmet oxon
26 Profenofos
27 Tebupiriamphos (Phostebupirim)
28 Terbufos
29 Terbufos-O-analogue sulfon
30 Tribuphos (DEF, s,s,s-Tr
31 tebupiramphos (Phostebupirim) oxygen analog
E
13
o
CL
O
.is
0
01
I.E.3 Page 23
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Attachment III.E.2: Summary of Reported Detection Limits for Raw, Finished, and
Outfall Samples
-*-=»
Limits of detection for nondetects
Chemical Detection Limit (ug/L)
Aztnphos-methyl
Azinphos-methyl-oxon
Chlorpyrifos
Chlorpyrofos, oxygen analo
Diazinon
Oiclorvos
Dicrotophos
Dimethoate
Disulfoton
bisulfoton sulfone
Oisulfotone sulfoxlde
Ethoprop
0.0010
0.0100
0.0150
0.0200
0.0300
0.0400
0.0500
0.0600
0.0700
0.0750
0.0800
0.0900
0.1000
0.0310
0.0600
0.0630
0.0800
0.0040
0.0050
0.0060
0.0100
0.0160
0.0020
0.0050
0.0060
0.0070
0.0100
0.0050
0.0160
0.0050
0.0170
0.0210
0.0050
0.0160
0.0030
0.0050
Samples reported
-------
f LITERATURE CITED
I Blomquist, J. D., 2001 . Transmittal of Preliminary Digital Data Sets From the USGS-
| USEPA Program "Pesticides in Water-Supply Reservoirs and Finished Drinking Water-
I A Pilot Monitoring Program." USGS, Baltimore, MD.
CM I
O i Faust, S.D. and O.M.. Aly.1999. Chemistry of Water Treatment. 2nd Ed. Lewis
I Publishers. Boca Raton, FL.
"--* | Larson, R.A. and E.J. Weber. 1994. Reaction Mechanisms in Environmental Organic
CD | Chemistry. Lewis Publications. Boca Raton, FL. pp 122-124.
3 |
-»-j I Magara, Y., T. Aizawa, N. Matumoto, and F. Souna. 1994. Degradation of pesticides
d [ by chlorination during water purification. Groundwater Contamination, Environmental
CD I Restoration, and Diffuse Source Pollution. Water Science and Technology. 30(7):1 19-
E 1 128.
to !
CO I Tierney, D.P., B.R. Christrensen, and V.C. Culpepper. 2001. Chlorine Degradation of
CD 1 Six Organophosphorus Insecticides and Four Oxons in Drinking Water Matrix.
CO | Submitted by Syngenta Crop Protection, Inc. Greensboro, NC. Performed by Syngenta
~2 I Crop Protection, En-fate, LLC., and EASI Laboratory.
_s£ | U.S. EPA. 2001. Laboratory Study on Chlorination and Softening Effects on Pesticide
CO I Residues in Drinking Water. Work Assignment (1-22) between EFED and ORD.
i U.S. EPA, 2000. Progress Report on Estimating Pesticide Concentrations in Drinking
0 | Water and Assessing Water Treatment Effects on Pesticide Removal and
> i Transformation: A Consultation. FIFRA Scientific Advisory Panel (SAP), September
3 | 29,2000. http://www.epa.gov/ scipoly/2000/September/sept-00-sap-dw-0907.pdf).
co i
E
o
CL
O
~o
0
co
CD
a:
I.E.3Page25
-------
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13
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a:
Appendices
E. Water Appendix
4. Effects of Drinking Water Treatment on Organophosphate Pesticides
The weight of evidence from open literature and studies conducted by a
registrant, an ORD/EPA laboratory investigation, and the USGS-EPA drinking
water reservoir monitoring program (Appendix III.E.3) show that parent
organophosphorus (OP) insecticides in raw drinking water are removed or
transformed during drinking water treatment. The most probable degradation
pathway is chemical oxidation through chlorination, and in some cases, chemical
water softening techniques may contribute to chemical degradation. In the
USGS-EPA pilot reservoir monitoring program, oxidation degradation products of
OP pesticides, such as sulfones, sulfoxides, and oxons, have been detected in
finished water samples from actual water treatment plants. Additionally, the
CO I drinking water reservoir monitoring data suggest that malathion degradation
CO | during the water treatment process may have led to malaoxon formation in some
CD | finished water samples. Laboratory studies have shown that oxons, which may
^ \ be relatively stable in chlorinated drinking water for periods of at least 24 - 48
jf2 I hours, are formed in chlorinated water. These data suggest that oxidative
"^ I degradation products such as oxons, sulfones, and sulfoxides have a likelihood
js^ I of occurrence in finished drinking water when organophosphorus pesticides are
CO I present in raw water.
fV I
""" I a. Introduction
CD f
> 1 This section provides a critical review of the available data that was used
-*"-* | to assess water treatment effects on removal and transformation of
JTO | organophosphorus pesticides and certain degradation products. This review
H3 I was conducted as an extension of the OPP water treatment literature review
CZ presented to a Federal Insecticide, Fungicide, and Rodenticide Act Scientific
Advisory Panel (FIFRA SAP) (http://www. epa.gov/scipoly/ 2000/September/
sept-00-sap-dw-0907.pdf). Documents in this report included information on
the chemistry of chlorination and softening in different water treatment
processes and their effects on organophosphorus pesticide degradation,
registrant-sponsored water treatment data, and ORD/EPA water treatment
data. In addition, water treatment effects are discussed in the USGS-OPP
pilot reservoir monitoring section.
The effects of water treatment were evaluated, with primary focus on
disinfection by chlorination and softening. Chlorine treatment is widely used
in the United States, and has been associated with the transformation of
certain organophosphorus pesticides to products with toxicity and health
concerns. Softening was also considered because organophosphorus
pesticides have the potential to hydrolyze under alkaline conditions.
I.E.4 Page 1
-------
I b. Drinking Water Disinfection
I Disinfection of raw or untreated water for potable uses is a process that is
| used to eliminate disease-causing or pathogenic microorganisms. The
i pathogens are generally bacteria such as Salmonella, viruses such as
CM | Poliovirus, and protozoa such as Cryptosporidium and Giardia. These
O microorganisms can be destroyed by physical treatment (heat or boiling),
ultraviolet (UV) radiation, or chemical treatment. UV radiation kills by
photodegradation of nucleic acids in microorganisms while chemical
treatment (chlorine or other oxidants) destroys pathogens by oxidizing the cell
walls. Other chemicals such as ozone, potassium permanganate, copper and
silver ions, quaternary ammonium compounds, strong acids and bases can
also inactivate microorganisms. In this report, however, the emphasis will be
on disinfection by treatment with chlorine and chlorine compounds.
CD
i
C
CD
E
CO
CO
i. Treatment by Chlorine and Chlorine Compounds
Currently in the United States, chlorine and its related compounds are
CD I commonly used for drinking water disinfection. By far, chlorine gas is the
W [ most widely used disinfectant in water treatment utilities and also can be
j2 [ used for oxidizing iron, manganese and hydrogen sulfide, and for
^ | controlling tastes, odors, algae, and slime. Other compounds, such as
V I sodium hypochlorite (NaCIO), chlorine dioxide (CI02), and chloramines
C/) 1 may be used In place of chlorine gas in other community water systems.
I Chlorine: (CI2) is a dense gas typically shipped in pressurized tanks
CD = to water treatment facilities. It dissolves in water and undergoes
> I hydrolysis or disproportionation as shown in equation. (1):
•*— ' I
_5? 1 CI2 + H2O = HOCI + H+ + CI" (1)
D i . • •
C | HOCI = H+ + OCI- (2)
J~* I The hydrolysis rate is so rapid that the reaction is complete in less
^-' [ than a second. The product HOCI (hypochlorous acid) also hydrolyzes
n 1 in water to form OCI" (hypochlorite) according to eq.(2), with an acid
Oi dissociation constant (pKa) of 7.5. The pKa value suggests that at pH
| of 7.5, 50% of HOCI exists as HOCI and 50% as OCI" . At pH
| conditions commonly encountered in finished or treated waters (~ pH
| 6-9), molecular CI2 is not practically important. At pH > 3 and with
(0 I chlorine dosage of 100 mg/L, very little or negligible CI2 is present.
> 1 Consequently, the dependence of HOCI dissociation on pH and
I distribution between of HOCI and OCI" are needed in order to
| understand the efficiency of disinfection by chlorine treatment along
\ with the chlorine effects on pesticides and other organic compounds.
[ HOCI and OCI" have considerably different capabilities of inactivating
I and destroying microorganisms. HOCI has a greater bactericidal
I . III.E.4 Page 2
-------
[ efficiency than OCI". The protonated species HOCI has been reported
| to be more reactive and has a higher oxidation efficiency than the
I unprotonated species OCI". Thus, it is important to measure pH as a
| • water quality parameter in water disinfection studies.
CNI i Hypochlorite: Sodium hypochlorite (NaCIO) and occasionally calcium
O I hypochlorite [Ca(CIO)2] are used instead of chlorine gas for water
I disinfection. Both salts dissolve to form the hypochlorite ion which
I eventually hydrolyzes in water according to eq. (3):
j OCI" + H2O = HOCI + OH" (3)
| With the formation of a strong base (OH"), the alkalinity of the water
*— | can be affected. One mole of NaCIO or 0.5 mole of Ca(CIO)2 will result
CD ! in an increase of one equivalent of alkalinity. This becomes significant
£~ I during superchlorination with hypochlorite in which a higher dose is
C/5 | used to achieve disinfection as well as remove iron and manganese
CO 1 and simultaneously control taste and odor.
CD =
MK" =
W I Chlorine Dioxide: CIO2, like chlorine, is a dense gas with chlorinous
I odor. However, unlike chlorine, it remains in a molecular form as CIO2
1 in water and does not undergo hydrolysis. Once dissolved in water, it
1 can be transformed under alkaline conditions to chlorite (CIO2"1) and
CO I chlorate (CIO3"1), both of which are undesirable in drinking water. It
I ' does not react with ammonia and does not form trihalomethanes,
I haloacetic acids, and other halogenated disinfection by-products
0 | typically associated with chlorine treatment. Disinfection/oxidation
> | products identified from CIO2 treatment include aldehydes and
*~^ | carboxylic acids, with low levels of some chlorinated compounds.
Z3 I Chloramines: Dissolved ammonia present or intentionally added to
I water can react with hypochlorous acid or hypochlorite to form
I chloramines. The stepwise reactions can be represented as follows:
NH4+ + HOCI = NH2CI + H2O + H+ (4)
CL i
>> I NH2CI + HOCI = NHCI2 + H2O .(5)
-Q I NHCI2 + HOCI = NCI3 + H2O (6)
0 !
CO i The products from reactions (4), (5), and (6) are respectively
"^ | monochloramine, dichloramine, and trichloramine or nitrogen
0 | trichloride. These chloramines have relatively lower biocidal and
I oxidation efficiency. Collectively, the three chloramine species
I contribute to the combined chlorine residual. The relative amount of
| each chloramine depends on pH and molar or dose ratio of CI:N. The
I free chlorine residual is associated with the concentration of HOCI or
I III.E.4 Page 3
-------
.*-=»
c
OCI"1or both. The total chlorine residual is taken as the sum of the free
and combined chlorine residuals which can be analytically determined
using procedures in Standard Methods of Analysis.
ii. Reactions of Chlorine with Organic Compounds and Pesticides
Chlorine gas and other chlorine compounds can react with chemicals
dissolved in water to form different disinfection products. In the water
treatment facilities, the reactions can be generally categorized as
oxidation, substitution/addition, and dechlorination.
Oxidation: All the disinfectants used in the United States have the
capacity to oxidize certain chemicals in raw or untreated water with
varying efficiencies. These chemicals are reduced metal ions,
aldehydes, ketones, alcohols, and other organic compounds that
include pesticides. Aldehydes and ketones can be converted to
carboxylic acids. Thiocarbamates can be transformed to sulfoxides,
and eventually to sulfones.. The P=S bond of organophosphate
pesticides (OPs) can be oxidized to P=O bond, leading to the
formation of oxon. Based on the available data, several OPs are
transformed to their corresponding oxons (Magara et al (1994);
Tierney, et al., 2000). For instance, diazinon is oxidized to diazoxon
which is relatively stable in chlorinated water for about 48 hours.
Substitution/Addition Reactions: HOCI or OCI1 can also react with
organic compounds by displacing chemical species and incorporating
chlorine atoms. This reaction is responsible for the formation of
trihalomethanes and haloacetic acids that are currently regulated
under the Disinfection By-Products rule (DBP). Other by-products
include chlorinated phenols, aromatic hydrocarbons, and alkenes.
Pesticides may also undergo substitution/addition reaction with
chlorine to form chlorinated products. Magara et al (1994) presented
chlorine treatment effects data that show the transformation of
thiobencarb to chlorobenzyl chloride, chlorobenzyl alcohol,
chlorobenzyl aldehyde, and chlorobenzoic acid. Some of these
treatment transformation products have been detected in a Japanese
water purification facility.
Dechlorination: Occasionally, the level of chlorine residual may be
high at the end of the treatment train. Thus, it is necessary to reduce
the chlorine residual before the finished water is transported through
the distribution system. This can be accomplished by dosing with
compounds that can react with chlorine or increase the rate of
decomposition, of chlorine residual.
Compounds typically used for dechlorination include sulfur dioxide
and reduced sulfur compounds such as sodium sulfite, bisulfite, and
II.E.4Page4
-------
I thiosulfate. In some instances, activated carbon can be used for
I dechlorination. Reactions of sulfur compounds such as sulfur dioxide
I generate acidic products (hydrochloric and sulfuric acids) that can
| decrease the alkalinity of the finished water.
CNI I c. Water Softening
P I
| Raw waters which are hard or those with high levels of calcium and
f magnesium are typically treated to reduce the concentrations of these two
I metal cations. This process, known as softening, can be achieved by the use
I of ion-exchange resins or precipitating agents. When lime and soda ash are
| added to water, the pH and carbonate alkalinity are increased which favor the
| precipitation of calcium as calcium carbonate and magnesium as magnesium
1 hydroxide. Under this condition, the pH can increase to about 10-11, leading
| to base-catalyzed hydrolysis of pesticides such as organophosphate
I insecticides. OPs are generally hydrolyzed in the environment by nucleophilic
CO I substitution reactions. At pH 7 at 20° C, the hydrolysis half-lives of certain
CO I OPs (Larson and Weber, 1994) are follows:
CD f
CO I Phosmet 7.1 hours
I Malathion 10.5 days
= Chlorpyrifos — 78 days
I Parathion 130 days
co i
I At softening pH of 10 -11 likely to be encountered in water treatment
I plants, hydrolysis rates would be expected to proceed much faster especially
01 .for phosmet and malathion.
> I
*~* ! d. EPA/ORD Studies on OP Pesticide Removal and Transformation by
ft? [ Water Treatment
C i EPA/ORD's AWBERC laboratory in Cincinnati, OH, conducted a laboratory
!± i study to determine the effects of chlorination and softening on certain
[ pesticides [U.S. EPA. 2001. Laboratory Study on Chlorination and Softening
I Effects on Pesticide Residues in Drinking Water. Work Assignment (1-22)
I between EFED and ORD.] Chlorpyrifos-methyl was one of the pesticides used
Of in the chlorination experiment. Malathion and phorate were used in the
§ softening experiment.
I
= i. Chlorination Jar Test
£/) i
^ I Well water was taken from a treatment plant in Ohio and then
Q) | subsequently used in the jar experiments for evaluating the effects of
| chlorination of several pesticides, including chlorpyrifos-methyl. The test
| water was spiked with about 20 - 1 00 ug/L of pesticides from the prepared
I stock solutions. The chlorination was performed under Uniform Formation
| Conditions (UFC): pH 8.0 ± 0.2; temperature of 20.0 ± .0°C; dark
| III.E.4Page5
-------
0
«*=»
incubation time of 24 ± 1 hr.; chlorine residual of 1.0 ± 0.4 mg/L as free
chlorine after 24 hr. The samples were dosed with hypochlorite-buffer
solution. After the test, the samples was quenched with sodium sulfite
prior to analysis. Chlorpyrifos-methyl, along with the other pesticides, was
analyzed according to Method 525.2 (GC/MS), which has a method
detection limit (MDL) of 0.025 for chlorpyrifos-methyl.
ii. Softening Jar Test
Well water used in the chlorination test was also used in the water
softening experiment. The raw water was spiked with < 20 to 300 ug/L of
pesticides that include 2 OPs, malathion and phorate. Hardness was
reduced by treating the raw water with 50 and 300 mg/L of lime which
corresponded to conventional magnesium softening conditions at about
20°C. Water was exposed to lime for 3 hr. before water samples were
analyzed using Method 525.2 (GC/MS). The MDLs for malathion and
phorate were 0.015 and 0.050 ug/L, respectively. The softening
experiment was conducted with 3 replicates for each pesticide.
Mi. Summary of Results
The well water used in both tests was analyzed for basic water quality
parameters and the results are summarized in Table III.E.4.1. The water
was slightly alkaline and had high hardness.
Table III.E.4.1. Raw Water Quality Characteristics Used in the USEPA ORD
Laboratory Studies
Parameter
Hardness (mg/L as CaCO3)
PH
Temperature (C°)
Alkalinity (mg/L as CaCO3)
Turbidity (NTU*)
TOC" (mg/L)
Sample I
315
7.44
23.6
220
2.7
1.39
Sample II
293
7.78
23.6
230
'l.4
1.36
-*=>
: *
NTU=Nephelometric Turbidity Unit
*TOC=Total Organic Carbon
Table III.E.4.2 shows the results of the chlorination and softening jar
tests for the 3 OP's. The concentrations represent the mean value of four
replicates for chlorination studies and three replicates for softening studies.
About 90% of chlorpyrifos-methyl was removed by chlorine treatment. The
reduction in pesticide concentration is most probably due to oxidation of
the insecticide to oxons and other products. During softening, relatively
higher removal efficiencies were observed in the 300 mg/L treatment than
I.E.4 Page 6
-------
Ct
0)
13
E
D
O
CL
O
0)
t/)
>
0
cr
those in the 150 mg/L treatment. More than 99 % of malathion was
removed, while phorate removal was lower (20%). It is believed that
alkaline hydrolysis was responsible for the significant concentration
reduction of malathion.
(N i
5 l
T— |
T— 1
'"-•^ =
CD |
i i
89*
% Removal
1 50 mg/L 300 mg/L
73* >99*
2 17*
i *Significantly lower than controls at 95%
e. Registrant Sponsored Water Treatment Data
Syngenta Crop Protection submitted a study to OPP in 2001 that evaluated
the effect of Chlorination on six OP pesticides and four of their oxon
transformation products [Tierney, D.P., B.R. Christrensen, and V.C.
Culpepper. 2001. Chlorine Degradation of Six Organophosphorus Insecticides
and Four Oxons in Drinking Water Matrix. Submitted by Syngenta Crop
Protection, Inc. Greensboro, NC. Performed by Syngenta Crop Protection,
En-fate, LLC., and EASI Laboratory.]. The results of the study are difficult to
interpret because the study does not contain water quality data, appropriate
treatment controls, and a complete description of sample storage data.
The data indicate that the six OP pesticides (acephate, azinphos-methyl,
chloropyrifos, diazinoh, malathion, and methamidophos) are transformed in
chlorinated drinking water. Chemical oxidation of the organophosphorus
compounds led to the formation of oxons for azinphos-methyl, chlorpyrifos,
diazinon, and malathion. The oxons were more stable than their parent
organophosphorus pesticides, and degradation of oxons was attributed to
non-chlorine degradation processes and/or hydrolysis. Chloramines were
formed during the experiment. Because chloramines have a lower oxidizing
potential than hypochlorous acid, the extent of degradation and formation of
I.E.4 Page 7
-------
oxidative degradation products (oxons) may be different under conditions of
equivalent or higher free chlorine concentrations.
i. Study Design
CM The study was designed to assess the impact of total residual chlorine
O on the degradation of six organophosphorus pesticides (acephate,
azinphos-methyl, chlorpyrifos, diazinon, malathion, and methamidophos)
and certain transformation products (azinphos-methyl oxon, chlorpyrifos
oxon, diazinon oxon, and malathion oxon).
CO
Study 1: OP Pesticides and Oxon Transformation Products (azinphos-
methyl, chlorpyrifos, diazinon, malathion, azinphos-methyl oxon,
' chlorpyrifos oxon, diazinon oxon, and malathion oxon)
Twenty liter samples of dechlorinated treated drinking water (total
(/) residual chlorine concentration^.02 mg/L as CI2) from the Jefferson
(/) • Parish Louisiana Water Treatment Plant were treated with sodium
CD hypochlorite to yield total residual chlorine (CI2) concentrations of 1.9
mg/L and 4.1 mg/L. The free chlorine concentration for the 1.9 mg/L
and 4.1 mg/L chlorine treatments was < LOD and ~2 mg/L,
respectively. Each bulk water sample was fortified with a working
V . standard mixture of organophosphorus pesticides or organophosphorus
(/) degradation products to yield pesticide concentrations of 0.500 ug/L
jy (500 ng/L).
Treatment controls were prepared using a 10 liter sample of finished
> drinking water from the Jefferson Parish Louisiana Water Treatment
Plant. The water sample was amended with sodium hypochlorite to
CO yield a total-chlorine residual of 2 mg/L. The total chlorine in the water
sample was removed by quenching with 300 mg/L of sodium
thiosulfate. A chlorine analysis of the water sample confirmed removal
of residual chlorine.
Pesticide fortified water and treatment controls were partitioned into
r\ separate 1 liter borosilicate glass jars. Three replicates were used for
Oeach of 5 sampling times (0, 15 minutes, 30 minutes,, 60 minutes, and
24 hours) and 3 chlorine concentrations (treatment control (no
chlorine), 2.0 mg/L, and 4 mg/L). Treatment controls had 3 replicate for
the 0 and 24 hours sampling interval. At each sampling time, the
C/3 chlorine residual in each 1 liter sample was removed through
quenching with ~300 mg of sodium thiosulfate. Residual Chlorine
removal was verified in a single sample fortified with 4.0 mg/L chlorine.
(V
At each sampling time, replicates samples were refrigerated at 4°C
prior to extraction. Samples were extracted using C-18 solid phase
extraction disks and analyzed using gas chromatography /mass
III.E.4Page8
-------
CM
O
spectrometry. The limit of detection (LOD) and limit of quantitation
(LOG) were 0.01 ug/L and 0.05 ug/L, respectively. The registrant
stated that all concentrations less than the LOG were considered as
non-detections. Quality assurance and control measures were
implemented. Each analysis group of 20 samples consisted of
experimental samples, method blank, matrix blank, matrix spike at
0.500 ug/L and duplicate matrix spike.
Diazinon, chlorpyrifos, and azinphos methyl were stable in
nonchlorinated control water, while malathion, diazinon oxon,
chlorpyrifos oxon, malathion oxon, and azinphos methyl oxon had
degraded significantly (p=0.05) degradation in the control water. After
24 hours, the percent remaining was 97% for diazinon, 96% for
chlorpyrifos, 76% for malathion, 90% for azinphos-methyl, 90% for
diazinon oxon, 85% for chlorpyrifos oxon, 55% for malathion oxon, and
62% for azinphos methyl oxon. The registrant stated that observed
C/3 I degradation may be due to non-chlorine degradation processes and/or
{ azinphos methyl oxon. Oxon degradation (21 to 40% of the peak
"-IP [ concentration) was observed in the 2 mg/L total chlorine treatment after
J5 I 24 hours.
•~3 i
Complete degradation of parent organophosphorus compounds
occurred in the 4 mg/L total chlorine treatment where degradation was
complete within 30 minutes. Oxidative degradation of parent
compounds led to the formation of oxons with peak oxon
concentrations were 60% for diazinon, 74% for chlorpyrifos, 64% for
malathion, and 31% for azinphos methyl. Oxon degradation appeared
to be partially dependent on oxidation from chlorine. Diazinon oxon
and chlorpyrifos oxon had significant degradation in the 4 mg/L
chlorination treatment. Malathion oxon and azinphos methyl
degradation was not significantly different than the treatment control.
Study 2: Acephate and Methamidophos
O
O
0
00
">
0
Cf
Chlorine degradation studies for acephate and methamidophos
were conducted using similar procedures as described above. The
experimental design were similar to the previously described study
III.E.4Page9
-------
I (Study 1). Modification in the experimental design are associated with
. | the pesticide fortification process and analytical methods. Because
I acephate degrades to form methamidophos, chlorine degradation
I studies were conducted for the individual compounds rather than a
I mixture of the two. The pesticide fortification method was different 1
CM I because an acetone co-solvent was used in the working standard
O 1 solution. The acetone co-solvent was allowed to evaporate prior to
| reconstitution in deionized water. The reconstituted solution was used
I to fortify bulk water samples.
I At each sampling time, the replicate samples were refrigerated at
I 4°C prior to extraction. Samples were extracted using AC-2 graphitized
I solid phase extraction tubes and analyzed using gas chromatography/
I flame photometric detection. The LOD and LOG were 0.01 ug/L and
i 0.05 ug/L, respectively. The registrant stated all concentrations less
1 than the LOG were considered as non-detections.
CO 1
CO i Methamidophos and acephate degraded in control water by 14%
CD | and 7%, respectively, during a 24 hour incubation period. In the 2 mg/L
CO I chlorine treatment, both compounds degraded by ~40% during a 24
CO | incubation period. Acephate and methamidophos were completely
^ I degraded within 15 minutes and 24 hours, respectively.
V i Methamidophos was not identified as an oxidative degradation product
CO I of acephate.
"(Y (
"- = ii. Uncertainties in Study
CD I
> | Water quality data, which are essential for understanding the water
chemistry, were not provided in the report. Important water quality
parameters include pH, hardness, alkalinity, total organic carbon content,
and concentrations of free chlorine, residual chlorine, NH4+, Na+, Ca+2,
Mg+2, SO4"2, Cl~, NO2", Br and F;". The Agency needs these data to confirm
the registrant's claim that ammonium concentrations in tap water led to the
j-^ I formation of chloramines. The only available water quality data for test
V-' I waters was pH (7.24). The registrant also submitted partial water quality
data which was unitless for alkalinity, hardness, total solids, and fluoride for
raw and treated water at the Jefferson Parish water treatment plant. The
lack of units prevents use of the water quality data.
O
"D
CD
CO
There are no data or adequate treatment control to assess the impact
of sodium thiosulfate on water chemistry. The treatment control water was
treated with 2 mg/L chlorine and then quenched with 300 mg/L sodium
thiosulfate. The study did not include a similar sodium thiosulfate
treatment regime was in the chlorine treatments and a control water
sample without sodium thiosulfate. The Agency recommends that
treatment control water be treated in the same manner as the water used
in chlorine treatments. The addition of sodium thiosulfate in the treatment
II.E.4Page10
-------
CD
c,
0)
E
C/)
c/)
0
0
>
*.*
03
13
o
Q.
O
"O
0
C/5
0
control confounds interpretation of the data when compared to the chlorine
treatments. Additionally, the lack of treatment control (without sodium
thiosulfate) limits the ability to assess the impact of sodium thiosulfate on
water chemistry.
Storage stability data used to compute average recovery were
incomplete. The registrant claim that average percent recoveries ranged
from 80 to 165% for extract storage times greater than 40 days. The
registrant submitted additional data on matrix spike recoveries to
substantiate the stability of analytes in extracts. Sample extracts were
stored for two months prior to chemical analysis. Registrant calculated
average matrix spike recoveries ranged from 59 to 83% for the C-18
method and 52 to 108% for the GC/PFD method. The relative percent
difference (RPD) for duplicate matrix spikes ranged from 1 to 12% for the
C-18 method and 8% to 48% for the GC/PFD method. Based on
performance standards, matrix spike recoveries for the C-18 and GC/PFD
methods should range from 70 to 120%. These data indicated that
analytical recoveries in matrix spikes for most analytes (exceptions
chlorpyrifos oxon and methamidophos) could be explained by analytical
CD I method performance. Low mean recoveries for chlorpyrifos oxon and
1 methamidophos, however, could not be explained by the method
| performance alone. The Agency believes the low recoveries of
I chlorpyrifos oxon and methamidophos suggest that degradation or some
I other factor contributed to low recoveries in matrix spike samples.
I.E.4 Page 1
-------
CM
O
CO
I. Appendices
E. Water Appendix
5. Chemical-Specific Inputs Used.in the Drinking Water Exposure
Assessment
Table III. E. 5-1 PRZM/EXAMS Input Values for Acephate
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
183.16
5.10E-13
1 .70E-06
8.01 E+05
0.09
4.7
0
4.6
19.8
2.3
0
0
18
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
Calculated
MRID 40390601 , cited in RED.
At 24°°C (Technical)
MRID 40390601 , cited in RED.
Technical at 25°°C
MRID 4050481 1 . Only value
available: adsorbed in only one
of the five soils (clay loam)
used in the batch equilibrium
studies.
MRID 40504811. Only value
available: adsorbed in only one
of the five soils (clay loam)
used in the batch equilibrium
studies.
MRID 41081603; stable at pH
7
No data available; used 2x
162-1 (MRID 00014991)
MRID 43971601 ;3x single
value of 6.6 days
MRID 00014991; 90% Cl on
mean using three values.
MRID 41 081 604; stable
MRID 41 081 604; stable
MRID 41081604
Foliar broadcast modeled in
RED; also includes in-furrow
treatments
Foliar broadcast or pre-plant @
2-4 in incorporation
c
0
E
00
CO
cr
0
CL
O
co
">
0
I.E.5 Page 1
-------
[ Table III.E.5.2. PRZM/EXAMS Input Values for Azinphos Methyl
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
317.32
2.20E-07
25.1
7.6
3.19
191.6
396
95.8
38
37
6.9
2
0
9.9
0.937
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
days
cmA-1
Comments / References
EFED One-Liner
MRID
EFED One-Liner
EFED One-Liner
MRID 42959702
MRID 40297001
2X aerobic soil input parameter
MRID 29900/ 2x anaerobic soil
input parameter
MRID 29900/ 3x single value
MRID 40297001
MRID 40297001
MRID 40297001
see EFED RED Chapter •
see EFED RED Chapter
OJ
O
CD
c
0
E
V)
co
0
(A
CO
CO
ir
0
D
E
d
Q_
o
0
CO
">
0
I.E.5Page2
-------
CM
O
Table III. E. 5.3. PRZM/EXAMS In
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic-
Metabolism >
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 1 7:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
put Values for Bensulide
Value
397.5
7.80E-08
8.20E-07
5.6
43.1
2943
200
726
0
363
230
220
220
1
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
RED; calculated value
MRID 41532001
MRID 41532001
MRID 42826701; average of 4
(11,30.5, 96.8, 34) values
MRID 42826701 ; average of 4
values
MRID 4051 3401: Stable
No study; value is 2x aerobic
soil metabolism input value
No study; stable in anaerobic
soil metabolism study (MRID
40460302)
MRID 40460301; single value
(not x3 because of large value)
MRID 00160074
MRID 00160074
MRID 00160074
Veg: unincorporated ground
Unincorporated or incorporated
to 4-cm depth
CO
t
c
V)
0)
0
07
cc
0)
.>
*-}—»
O
a,
O
"O
0
CO
Q)
n:
I.E.5Page3
-------
I Table III.E.5.4. PRZM/EXAMS Input Values for Chlorethoxyfos
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
336
8.00E-03
1.70E-03
2.1
111
27
46
94
23
72
59
4.3
7
2
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days ,
days
days
days
days
days
integer
cm
Comments / References
MRID
MRID
MRID
MRID
MRID 41 29061 8; mean of 40,
53, 150,200
MRID 41736821
No study available; 2x aerobic
soil metabolism half-life value .
No study avail; 2x anaer soil
met t1/2 of 47 da; MRID
41736825
Range 20-23 da; MRIDs
40883706,41736824
MRID 40883705
MRID 40883705
MRID 40883705
In-furrow, t-band (11/23/98 DW
assessment, Matzner)
1 1/23/98 DW assessment,
Matzner
CM
O
CD
i
C
CD
E
C/)
C/)
CD
C/)
C/)
C/)
o:
0)
D
E
D
O
CL
O
"O
0
CD
a:
I.E.5 Page 4
-------
Table III.E.5.5. PRZM/EXAMS In
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
put Values for Chlorpyrifos
Value
351
4.20E-06
1.87E-05
2
6070
30
154
126.7
77
72
72
16
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
RED
RED
RED
MRIDs 00155636, 00155637,
40050401,41892801,
41892802, 42493901; mean of
range 360-3 1000
MRID 41 747206
No study avail; 2x aerobic soil
metabolism input
No study avail; 2x anaerobic
soil met (15-58 da), MRID
00025619
90%th pet Cl on mean of range
11-180 da; MRIDs 00025619,
42144911,42144912
MRID 001 55577
MRID 001 55577
MRID 001 55577
Includes both aerial/foliar and
ground/broadcast/incorporated
C
0)
V)
CO
C/3
0.
>
13
J^MV
Meitt^.'
-J
o
CL
O
CD
C/3
>
0)
CC
I.E.SPageS
-------
CM
O
Table III.E.5.6. PRZM/EXAMS In
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life .
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
put Values for Diazinon
Value
304.34
1.40E-06
1.40E-04
40
758
52
82
164
41
12
138
77
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L ,
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
RED
RED
RED
MRID 40512601 ; see Jones,
2000; D271987
MRID 001 53229; see Jones,
2000; D271987
RED Chapter for Diazinon; 2x
aerobic soil metabolism value
2x aerobic aquatic metabolism
value
EFED RED Chapter for
Diazinon; 90% Cl on mean
EFED RED Chapter for
Diazinon
EFED RED Chapter for
Diazinon
EFED RED Chapter for
Diazinon
CD
i
C
0
£
CO
CO
0
(A
CO
CO
a:
0
_03
•13
E
D
O
CL
O
0
CO
">
0
a:
I.E.5 Page 6
-------
Table III.E.5.7. PRZM/EXAMS In
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
put Values for Dichlorvos (DDVP)
Value
221
5.01 E-08
1.21E-02
15000
37
0
2.5
12.6
1.25
12
5
0.875
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
From RED
Measured (from RED)
From RED
41723103,40034904
43326601 -stable with longer
irradiated half-lives than dark
control
no data; 2x aerobic soil
metabolism half-life value
no data; 2x anaerobic soil
metabolism half-life value
(43835701)
41 7231 02; 3x single half-life
value
41723101
41723101
41723101
o
c
Q)
E
CO
CO
0
CO
CO
0
Z3
O
CL
"O
©
CO
0)
fY
I.E.5 Page 7
-------
I Table III.E.5.8. PRZM/EXAMS Input Values for Dicrotophos
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT ,
PLDKRT
FEXTRC
Value
237.19
3.13E-11
7.00E-05
11990
73
0
18
0
9
117
72
28
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID 43772301
RED; calculated
MRID 43500401
MRID 43603202, 43603201
;
MRID 001 60828; mean of 11,
40,53, 187
stable; 160824
No data; aer soil met input
value x 2
no data
160826, single value (3 days) x
3
160823
160823
160823
CM
O
CD
C
0
E
.to
0
I.E.5 PageS
-------
Table III. E. 5.9. PRZM/EXAMS Input Values for Dimethoate
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
229.2
8.00E-11
1.85E-06
4.00E+04
0.42
0
14.4
, 44
7.2
156
68
4.4
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
RED
RED
RED
MRID 00164959; average of 4
(0.06, 0.30, 0.57, 0.74) values
MRID 001 59762: Stable
No study; value is 2x aerobic
soil metabolism input value
No study; value is 2x anaerobic
soil metabolism input value
(MRID 42843201)
MRID 42843201 ;3x single
half-life value
MRID 00159761
MRID 00159761
MRID 001 59761
Typically foliar application
CD
i
.4-.»
c.
C/)
0
CO
E
13
O
GL
O
"O
0
c/)
">
0
I.E.5 Page 9
-------
I Table III.E.5.10. PRZM/EXAMS Input Values for Disulfoton Total Toxic Residues
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZWI
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
274.39
2.60E-06
1.8X10-4
15
552
4
260
260
1174
323
231
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
Parent; MRID 150088
Parent; RED
Parent; RED
Parent; MRID 150088
Parent; MRID 443731 03; no
data fro sulfoxide & sulfone,
which are expected to be more
mobile than parent
Parent; MRID 40471 102; 93 hr
half-life
Set to = aerobic soil
No valid study available
MRIDs 43800101, 40042201,
41 5851 01; Sulfoxide = 17
days; sulfone =1.50 days; upper
Cl on mean
parent; MRID 00143405
parent; MRID 00143405
parent; MRID 00143405
Foliar diss rate 3.3 da; MRID
41201801
i
CM
O
CD
CD
E
CO
CO
CD
CO
CO
CO
DC
CD
13
E
D
O
CL
O
"O
CD
CO
">
CD
o:
I.E.5Page10
-------
Table III.E.5.11. PRZM/EXAMS Input Values for Disulfoton Parent Compound Only
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
274.39
2.60E-06
1.8X10-4
15
552
4
12
6
1174
323
231
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID 150088
RED (measured)
RED; 20C
MRID 150088, 20 C
MRIDs 44373103, 00145469;
mean of 386, 449, 483, 888
MRID 40471 102; 93 hr half-life
No study available; 2x aerobic
soil metabolism input value
No valid study available
MRIDs 43800101 , 40042201 ,
41585101; 90% Cl on mean of
2 values
MRID 00143405
MRID 00143405
MRID 00143405
Foliar diss rate 3.3 da; MRID
41201801
CD
CO
0
if
0
o
CL
"O
0)
c/s
'>
0
I.E.5Page11
-------
I Table III.E.5.12. PRZM/EXAMS Input Values for Ethoprop .
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZWI
Variable
Name
mwt .
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
242.3
1 .49E-07
3.50E-04
843
2.1
0
600
300
300
0
0
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer '
cm
Comments / References
RED
RED
RED
RED
MRID not given in RED;
average of 4 (1.08, 1.24,2.10,
3.78) values
MRID
MRIDs 41270702, 43833502;
stable
No study; value is 2x aerobic
soil metabolism input value
MRID 00160171; 3x single
half-life value
MRID 00160171; 3x single
half-life value
MRID 41 270703; stable
MRID 41270703; stable
MRID 41270703; stable
Incl. band incorporation, soil
broadcast, broadcast incorp,
in-furrow
Incorporated or watered in
CM
CO.
to
to
I.E.5Page12
-------
Table III.E.5.13. PRZM/EXAMS Input Values for Fenamiphos Total Toxic Residues
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC '
Value
303.36
9.97E-10
400
0.958
75
336
399
168
247
300
231
4
2
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
EFED RED chapter; parent
EFED RED chapter; parent
EFED RED chapter; parent
MRID 407748-08; lowest non-
sand Kf for parent; sulfoxide,
sulfone more mobile in column
caching
MRID 40608001; parent,
corrected for dark control
MRID 421493-03; 2x aerobic .
soil input parameter
MRID 412869-01; 6x anaerobic
soil metabolism rate
MRID 421493-03; half-life 62 d
for sulfoxide, 29 d for sulfone;
comb residue 56 days (x3)
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
CM
O
"•"««*,
c
0
05
0
C/3
0
>
O
Q,
O
"O
0
GO
">
0
01
I.E.5Page13
-------
Table III.E.5.14.
Only
PRZM/EXAMS Input Values for Fenamiphos Parent Compound
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
303.36
9.97E-10
400
0.958
75
12
399
13.3
247
300,
231
4
2
f
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
EFED RED chapter
EFED RED chapter
EFED RED chapter
MRID 407748-08; lowest non-
sand Kf
MRID 40608001; corrected for
dark control
MRID 421493-03; 2x aerobic
soil input parameter
MRID 412869-01; 6x anaerobic
soil metabolism rate
MRID 421493-03; 3x single
value
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
MRID 421493-02; see Jones,
RD, 2001, Revised
Fenamiphos Est. Env. Cone.
Osl
O
CO
c
0
E
c/)
C/)
0
C/)
CO
(A
15
D
E
D
O
CL
O
"O
0
00
0
o:
I.E.5Page14
-------
I Table III.E.5.15. PRZM/EXAMS Input Values for Malathion
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure .
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
330
1.20E-07
4.00E-05
145
151
156
3.27
7.5
3
107
6.2
0.5
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
RED
EFED One-liner
EFED One-liner
RED
MRID 41 345201
MRID 41673001, 43166301
without acetone sensitizer
MRID 42271601, 43163301 3x
single value, value uncertain
MRID 42216301, 43166301 3x
single value, value uncertain
MRID 41721701, 43163301,
see RED Appendix 3
MRID 40941201, 43166301
MRID 40941201, 43166301
MRID 40941201, 43166301
RED used 90% of dissipation
values, should not have
Csf
o
CD
i
E
CO
CO
o
(to
tO
CO
ir
0
13
E
13
O
QL
O
"O
0)
CO
">
CD
I.E.5Page15
-------
I Table III.E.5.16. PRZM/EXAMS Input Values for Methamidophos
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility >
Kd
Koc <•
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
141.14
1.60E-11
1.73E-05
. 200000
1.5
200.5
3.5
0
1.75
0
27
3.2
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
EFGWB One-Liner
Calculated
MRID 43661003. At24°°C
(Technical)
MRID 43661 003.
MRID 4050481 1 . Only one Koc
value available, adsorbed in
only one of the five soils (clay
oam) used in batch equilibrium
studies.
MRID 001 5061 0;pH 5 (dark
control-corrected)
No data available; used 2x
162-1 (MRID 00014991)
No anaerobic aquatic
metabolism data are available.
Since significant hydrolysis
occurs at pHs >5, assume
compound is stable to aquatic
metabolism.
MRID 41372201; 3 X single
value of 14 hours.
MRID 001 50609
MRID 001 50609
MRID 00150609
CM
O
CD
C
0
E
0
V)
CO
0
13.
E
ZJ
O
Q_
O
"O
0
">
0
.E.5Page16
-------
[ Table III.E.5.17. PRZM/EXAMS Input Values for Methidathion
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZNI
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
302.3
3.97E-09
2.48E-06
250
325
11
39.8
20
19.9
37
48
13
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID
MRID
MRID
MRID
MRID
MRID (001 58529)
MRID (42081709)
(see asm, 2 x of asm
value)MRID
(2 x soil anaerobic value) MRID
(42262501)
MRID (44545101, 4226501)
90%ile value
MRID (42037701, NOTE: pH 4
not 5)
MRID (42037701)
MRID (42037701)
CN
O
v—
C
0
to
GO
0)
(/)
CO
CO
03
O
CL
O
o
to
">
0)
a:
I.E.5Page17
-------
I Table III.E.5.18. PRZM/EXAMS Input Values for Methyl Parathion
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZWI
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
PSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
265
6.12E-07
9.70E-06
60
487
2.04
12.3
1.5
11.25
. 68
40
33
2
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID
MRID
MRID
MRID
MRID
MRID 40999001
MRID 40809701
MRID 41768901 3x single
value
MRID 41 768901 3x single
value
MRID 41 735901 3x single
value
MRID 001 3275,40784501
MRID 001 3275,40784501
MRID 001 3275,40784501
simulated washoff 0.5 cm-1
Csl
O
CO
i
c
0
E
0
a:
I.E.5Page18
-------
I Table III.E.5.19. PRZM/EXAMS Input Values for Naled
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
381
1.13E-07
4.50E-04
2000
180
69
1.5
4.5
1.00
4
0.64
0.07
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
Merck
Calculated
00161100,40279200,
40394904,41354104,
41 3541 05 and 41 3541 06
41 31 0702 and 424451 03
from RED
MRIDs 40618201, 41354102,
42445101
85408
40034902 and 41 3541 01
40034902 and 41 3541 01
40034902 and 41 3541 01
CM
O
CD
i
C
CD
E
CO
CO
0
I.E.5Page19
-------
! Table III.E.5.20. PRZM/EXAMS Input Values for Oxydemeton Methyl
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
246
9.26E-09
2.86E-05
1000
0.45
466
19.2
10.5
9.6
93
40
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
40620301
Calculated
42951203
42951203
mrid 40884201
mrid 40781 501 ; corrected for
dark control (137 in light, 194 in
dark)
no study; 2x aerobic soil
metabolism input value
42901801 half-life *3
MRID 42831 501, 3.2 days x 3
MRID 001430547, hydhaf was
used
MRID 001430547, hydhaf was
used
MRID 001430547, hydhaf was
used
T-band?
1
a
c
CO
CO
CD
CO
CO
C/)
"5—*
"D
CD
CO
I.E.5Page20
-------
I Table III.E.5.21. PRZM/EXAMS Input Values for Phorate Total Toxic Residues
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
260
2.87E-08
7.50E-04
8926
0.53
91
2
11
53
121
3
3
4
8
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID 41 297901; parent
Calculated
MRID 41 049502; parent
MRID 41 049501 ; sulfoxide
MRID 44671204;
sulfoxide/more mobile
MRID 41 348508
MRID 44863002, total toxic
half-life based on applied
parent and degradates
41936002; 2x anaerobic soil
metabolism value
(Getzwin and Shanks, J. Econ.
Entom. 63:52-58) (linear, total
toxic half-life)
MRID 41 348507
MRID 41 348507
MRID 41 348507
Corn_ t-band (cam 7);
cotton/peanuts cam 8
1 .27 cm for cotton; 2.5 cm for
corn, peanuts
•Vi
o
c
0)
0
&
c/3
CD
F
5
O
CL
O
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o
0)
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0
I.E.5Page21
-------
1 Table III.E.5.22. PRZM/EXAMS Input Values for Phorate Parent Compound Only
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp .
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
260
5.13E-07
7.50E-04
500
4.04
2
1.5
53
8.3
3
3
4
7
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
41297901
Calculated
41049502
41049501
42208201
41348508
44863002; 3x single value
41936002; 2x anaerobic soil
metabolism value
(Getzwin and Shanks, J. Econ.
Entom. 63:52-58) (non-linear,
no adjustment of value)
MRID 41348507
MRID 41 348507
MRID 41348507
Corn_t-band (cam 7);
cotton/peanuts cam 8
1.27 cm for cotton; 2.5 cm for
corn, peanuts
CM
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CD
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C/)
CD
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C/)
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o:
CD
I?
13
E
13
O
CL
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CD
02
CD
I.E.5Page22
-------
1 Table III.E.5.23. PRZM/EXAMS Input Values for Phosmet
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
317.3
7.50E-09
4.50E-07
25
8.2
0
18
30
9
7.5
0.4
0.004
2
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days'
days
days
days
integer
cm
Comments / References
RED
RED (calculated)
RED
RED
MRID 40599002; average of 4
(1.17, 12.4, 13.6, 15.8) values
MRID
MRID 42607901: Stable
(hydrolysis likely mechanism of
degradation)
No study; value is 2x aerobic
soil metabolism input value
No study; value is 2x anaerobic
soil metabolism input value
(MRID 41497801)
MRID 0011 2304; 3x single
half-life value [compare w/ field
dissipation t1/2s of 5-19 da)
MRID 40394301
MRID 40394301
MRID 40394301
aerial app (2) for alfalfa; air
blast for fruit crops
CM
O
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CD
i
"c
CD
I.E.5 Page 23
-------
I Table III.E.5.24. PRZM/EXAMS Input Values for Phostebupirim
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis;
Hydrolysis:'
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
318.4
3.80E-05
5.5
1779
1.3
666
558
333
47
45
41
7
0
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
r
days
days '
days
days
integer
cm
Comments / References
Kd ranged from 12.4 to 15.6
MRIDs 420054-69, -70; mean
of 2674, 2137, 1024, 1281
MRID 42005467; no
degradation in dark control
No study; value is 2x aerobic
soil metabolism input value
No study; 2x anaerobic soil
metabolism value (279 da,
MRID 42005468)
343 da @ 34x max rate (MRID
42005468); 55, 82, 343 da @
max label rate (MRID
44299803, supplemental) -
90% Cl on mean
MRID 42005465
MRID 42005465
MRID 42005465
Granular; bands, t-bands, in-
furrow
No incorporation modeled,
1 2/8/97 DW assessment
CNJ
O
CO
i
c
CD
E
CO
CO
0
CO
CO
CO
0
O
CL
O
"O
0
CO
">
0
or
I.E.5Page24
-------
I Table III.E.5.25. PRZM/EXAMS Input Values for Profenofos
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
374
1.83E-08
6.70E-09
2
9.7
75
12
9
6
108
62
0.3
2
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID
MRID
MRID
MRID
MRID 41 6273-11 (average of
4.6, 7.5, 17 - non-clay soils)
MRID
MRIDs 418799-01, 419390-02
2x aerobic soil met. value; no
aerobic aquatic study available
3x single value (3 da); MRID
422181-01
3x single value (2 da); MRID
423343-02
MRIDs 416273-09, 419390-01
MRIDs 416273-09, 419390-01
MRIDs 416273-09, 419390-01
2 for aerial spray; 7 for banded
CM
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Q)
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a:
0)
JS
D
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O
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a:
I.E.5Page25 .
-------
I Table III.E.5.26. PRZM/EXAMS Input Values for Terbufos Total Toxic Residues
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 1 8:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND ,
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
288
3.73E-08
3.16E-04
3210
58
1
23
34
129
0
0
0
7
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
MRID 41297901; parent
Calculated
MRID 41 049502; parent
MRID 41049501, for sulfoxide
since it is the predominant toxic
residue
MRID 41 373604;
sulfoxide/sulfone
MRID 161567
44862502, total toxic terbufos
half-life from applied
compounds
41749801, total toxic residues
00156853, linear degradation
of total toxic residue
MRID 00087694;
Bowman&Sans (1982) indicate
metabolites stable @ acidic pH
MRID 00087694;
Bowman&Sans (1982) indicate
metabolites stable @ acidic pH
MRID 00087694;
Bowman&Sans (1982) show
rates of 41 da for sulfoxide +
32 da for sulfone; using aquatic
metabolism data to capture
hydrolysis + metabolism
Corn, sorghum, beets CAM 7
(t-band}_
Incorporated to 2.5 cm
CM
O
CD
C
0)
E
CO
CO
Q)
CO
CO
CO
o:
0)
13
E
D
O
a.
O
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CD
CO
0)
a:
l,E.5.Page26
-------
I Table III.E.5.27. PRZM/EXAMS Input Values for Terbufos Parent Compound Only
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
288
2.39E-05
3.16E-04
5
633
1
1.5
11.7
5.6
12
13
14
7
2.5
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
41297901
Calculated
41049502
41049501
41373604
161567
44672004; pond water only,
upper 90th Cl on mean
41749801
00156853 (non-linear, no
adjustment of value because of
formation and decline)
MRID 00087694
MRID 00087694
MRID 00087694
Corn, sorghum, beets CAM 7
(t-band)
incorp to 2.5 cm
CM
O
CO
I
c
0)
CO
CO
Q
CO
C/5
» t--*ta«g
rv
>
4-J
CD
13
O
QL
O
73
0)
0
o:
I.E.5 Page 27
-------
I Table III.E.5.28. PRZM/EXAMS Input Values for Tribufos
Property/ Parameter
Molecular weight
Henry's Law Const.
Vapor Pressure
Solubility
Kd
Koc
Photolysis half-life
Aerobic Aquatic
Metabolism
Anaerobic Aquatic
Metabolism
Aerobic Soil
Metabolism
Hydrolysis:
Hydrolysis:
Hydrolysis:
Method:
Incorporation Depth:
Record 17:
Record 18:
PRZM
Variable
Name
mwt
henry
vapr
sol
Kd
Koc
kdp
kbacw
kbacs
asm
pH5
pH7
pH9
CAM
DEPI
FILTRA
IPSCND
UPTKF
PLVKRT
PLDKRT
FEXTRC
Value
314
1.70E-06
2.3
76.9
9300
0
1490
150
745
0
0
124
Units
g/mol
atm-mA3/mol
torr
mg/L
mg/L
mg/L
days
days
days
days
days
days
days
integer
cm
Comments / References
9/6/00 Updated DW memo
from D. Spatz, D. Young
9/6/00 Updated DW memo
from D. Spatz, D. Young
9/6/00 Updated DW memo
from D. Spatz, D. Young
MRID 42350004; average of 4
(66.8,60.6,74.3, 106) values
9/6/00 Updated DW memo
from D. Spatz, D. Young
MRID 41 71 9401: Stable
No study; value is 2x aerobic
soil metabolism input value
MRID 43325504; 5-mot1/2,
9/6/00 Spatz/Young DW memo
MRID 42007204; single value.
(not x3 because of high value)
MRID 41618814: Stable
MRID 41618814: Stable
MRID 41618814
See PRZM manual
CM
O
CO
c
CD
E
-------
I III. Appendices
I E. Water Appendix
I 6. Water Exposure Assessment: Application-Specific Input Parameters for
C\f | PRZM/EXAMS by Region
o i
The tables presented in this region summarize the region-specific input
parameters for each of the crop-OP uses modeled in each region. For each
chemical, the tables provide:
Q PRZM scenario file name - the scenario input file, documented in Appendix
III.E.7
Q Crop on which the pesticide is used
(/) I Q Application method (PRZM CAM variable) and the general application
C/5 | method documented in Appendix III.E.8
W | Q Depth of incorporation, based on available information on usage in the
chemical-specific risk assessments
Q Application rate (kg/ha) based on the usage information documented in
Appendix III.E.8
Q Application efficiency, set according to USEPA OPP's input parameter
guidance
Q Spray drift fraction, documented in Appendix III.E.9
Q Application date, based on usage, growth stage, and most active application
CO
P
•0
0
period documented in Appendix III.E.8
""3
OG Interval between additional applications, if any, based on usage information
documented in Appendix III.E.8
CL
I.E.6 Page 1
-------
a. Region A (Florida) Application Parameters
Chemical
Chlorpyrifos
3horate +
Dearadates
Ethoprop
Dhorate +
Dearadates
Chlorpyrifos
Chlorpyrifos
Chlorpyrifos
Chlorpyrifos
Acephate
Vlethamidopho
s (Acephate
degradate)
Diazinon
Diazinon
VIethamidopho
5
PRZM scenario
File name
FLsweetcornC
-LsweetcornC
rLsugarcaneC
=LsugarcaneC
FLcitrusC
rLcitrusC
FLcitrusC
-LcitrusC
rLcucumberC
-LcucumberC
FLcucumberC
FLcucumberC
-LcucumberC
Crop/Use
Corn
Corn
Sugarcane
Sugarcane
Grapefruit
Orange
Tangelo
Tangerine
Deppers
Peppers
Lettuce
Tomato
Tomato
App. Meth. (CAM)
2
Aerial/ foliar
7
Ground/ at plant
4
Ground/ at plant
4
Ground/ at plant
2
Airblast/foliar
2
Airblast/foliar
2
Ground/ at plant
2
Airblast/foliar
2
Ground / foliar
2
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
Incorp.
Depth
(cm)
0
2.5
10
2.5
0
0
0
0
0
0
0
0
0
App. Rate
(kg/ha)
0.73
1.44
3.89
4.44
2.09
0.63
1.12 '
0.80
0.84
0.21
acephate *
0.25
0.77
0.64
0.52
Applic.
Effic..
0.99
1
1
1
0.99
0.99
0.99
0.99
0.99
1
0.99
0.99
0.99
Spray Drift
(D
0.055
Aerial
0.85
Frac in top 2
cm
0
No Drift
0
No Drift
0.0087
Air Blast
0.0087
Air Blast
0.0049
Ground
0.0087
Air Blast
0.0049
Ground
0
degradate
0.0049
Ground
0.0049
Ground
0.0049
Ground
App. Date
15-Feb
1-Sep
1-Sep
. 1-Sep
1-Jan
1-Jan
1-Jan
1-Jan
25-Jan
27-Jan
22-Jan
23-Jan
19-Feb
Interval between apps (days)
1
228
**
45
45
45
263
***
263
k**
266
***
282
***
255
***
2
51
51
55
3
4
5
D
(1) Spray drift load estimated using Ag-Drift.
*** To populate app dates, listed app dates in chronological order w/in
year
I.E.6 Page 2
-------
b. Region B (Northwest) Application Parameters
Chemical
Azinphos
Methyl
Chlorpyrifos
Diazinon
Dimethoate
Malathion
Phosmet
Azinphos
Methyl
Chlorpyrifos
Methidathion
3hosmet
Diazinon
Azinphos
Methyl
Chlorpyrifos
Diazinon
Dimethoate
PRZM
scenario file
name
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
ORapoleC
ORappleC
ORappleC
ORappleC
ORappleC
ORappleC
Crop/Use
Apples
Apples
Apples
Apples
Apples
Apples
Pears
Pears
Pears
Pears
Pears
Cherry, Sweet
Cherry, Sweet
Cherry, Sweet
Cherry, Sweet
App. Meth..
(CAM)
2
Ground/ Foliar
2
Ground/ Dormant
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Dormant
2
Airblast/ Dormant
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Dormant
2
Airblast/ Dormant
2
Airblast/ Foliar
Incorp.
Depth
(cm)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
App.
Rate
(kg/ha)
0.99
2.04
0.72
0.85
1.04
2.49
1.08
2.24
1.45
3.17
1.15
0.97
2.44
1.08
0.90
App.
Effic.
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
Spray Drift
(1)
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
App.Date
1-May
1-Feb
1-Feb
1-May
1-May
1-May
15-Apr
1-Feb
1-Feb
15-Aor
15-May
15-May
1-Feb
1-Feb
15-Apr
Interval between applications
(days)
1
41
103
31
61
61
61
2
41
3
4
5
6
I.E.6 Page 3
-------
Chemical
Dimethoate
Jiazinon
Phosmet
Chlorpyrifos
Chlorpyrifos
Diazinon
Ethoprop
Dimethoate
Diazinon
Bensulide
Chlorpyrifos
Diazinon
Disulfoton +
degradates
Naled
DDVP (naled
degr)
Bensulide
Chlorpyrifos
Dimethoate
PRZM
scenario file
name
ORappleC
ORappleC
ORappleC
ORfilbertsQ
ORswcorn
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
Crop/Use
Cherries, Tart
Cherries, Tart
Cherries, Tart
Hazelnuts
Sweet Corn
Beans, snap
Beans, snap
Peas, green
Peas, green
Broccoli
Broccoli
Broccoli
Broccoli
Broccoli
Broccoli
Cabbage
Cabbage
Cabbage
App. Meth..
(CAM)
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
2
Airblast/ Foliar
4
Ground / At-plant
2
Ground/ foliar
2
Ground/ at-plant
2
Ground/ foliar
2
Ground/ foliar •
1
Ground/ at plant
4
Ground/ at plant
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Degradate
1
Ground/ at plant
4
Ground/ at plant
2
Incorp.
Depth
(cm)
0
0
0
0
5
0
0
0
0
0
5
0
0
0
0
0
5
0
App.
Rate
(kg/ha)
1.01
1.01
1.78
1.38
1.48
0.61
2.69
0.20
0.56
4.04
1.42
0.90
1.13
1.55
0.31
naled *
0.2
4.24
0.74
0.53
App.
Effic.
0.99
0.99
0.99
0.99
1.00
0.99
1
Granular
0.99
0.99
0.99
0.99
0.99
0.99
0.99
1.00
0.99
0.99
0.99
Spray Drift
(1)
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0049
Ground
0.0049
Ground
0
Granular
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground •
0.0049
Ground
0.0049
Ground
0.0049
Ground
0
degradate
0.0049
Ground
0.0049
Ground
0.0049
App.Date
15-Apr
1-Feb
15-May
15-Apr
15-Apr
15-Jun
30-Apr
1-May
1-May
1-May
1-May
1-Jul
1-Jul
1-Jul
1-Ju
15-Mar
15-Mar
15-Jul
Interval between applications
(days)
1
23
23
2
3
4
5
3
I.E.6Page4
-------
Chemical
ODM
Acephate
Methamidoph
os (acephate
degradate)
Diazinon
Dimethoate
^Jaled
DDVP (naled
degradate)
Bensulide
Vlalathion
Chlorpyrifos
Diazinon
Malathion
MethylParath
on
Chlorpyrifos
Chlorpyrifos
Dimethoate
PRZM
scenario file
name
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORsnbeansC
ORgrassseed
--\
i^
ORXmasTree
ORXmasTree
Crop/Use
Cabbage
Cauliflower
Cauliflower
Cauliflower
Cauliflower
Cauliflower
Cauliflower
Cucumbers
Squash
Onions
Onions
Onions
Onions
Grass for
seed
Christmas
Trees
Christmas
Trees
App. Meth..
(CAM)
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Degradate
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Degradate
1
Ground/ at plant
2
Ground/ foliar
4
Ground/ at plant
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Airblast/ foliar
2
Airblast/ foliar
Incorp.
Depth
(cm)
0
0
0
0
0
0
0
0
0
5
0
0
0
0
0
0
App.
Rate
(kg/ha)
0.63
0.93
0.23
acephate
*0.25
0.60
0.44
1.57
0.31
naled *
0.2
3.60
1.59
1.13
0.89
2.06
0.56
1.11
1.11
0.56
App.
Effic.
0.99
0.99
1.00
0.99
0.99
0.99
1.00
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
Spray Drift
(1)
Ground
0.0049
Ground
0.0049
Ground
0
0.0049
Ground
0.0049
Ground
0.0049
Ground
0
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0087
Airblast
0.0087
Airblast
App. Date
15-Jul
15-Aug
17-Auc
15-Aug
15-Aug
15-Aug
1 5-Aug
10-May
1-Ju
20-Mar
1-Jul
1-Jul
1-Ju
1-Apr
1-May
1-May
Interval between applications
(days)
1
23
'
31
15
31
31
2
3
4
5
6
III.E.6Page5
-------
Chemical
ODM
Acephate
vlethamidoph
os (acephate
degradate)
Chlorpyrifos
Diazinon
Diazinon
Acephate
Methamidoph
os (acephate
degradate)
Chlorpyrifos
AzinphosMet
Wl
Diazinon
Diazinon
Malathion
Diazinon
Malathion
PRZM prop/Use
scenario file I
name I
ORXmasTree Christmas
[frees
ORXmasTree Nursery/Tree
B-Shrubs
ORXmasTree [Nursery/Tree
~" B-Shrubs
ORXmasTree
ORXmasTree
ORhopsC
ORmintC
ORmintC
ORmintC
ORberriesC
ORberriesC
ORberriesC
ORberriesC
ORberriesC
ORberriesC
Nursery/Tree
s-Shrubs
Mursery/Tree
s-Shrubs
Hops
Mint
Mint
Mint
Blackberry
Blackberry
Blueberry
Blueberry
Raspberry
Raspberry
App. Meth..
(CAM)
2
Airblast/ foliar
2
Ground/ foliar
2
Degradate
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Degradate
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
2
Ground/ foliar
Incorp.
Depth
(cm)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
App.
Rate
(kg/ha)
0.42
1.11
0.28
acephate
*0.25
1.11
0.77
1.11
1.08
0.27
acephate
*0.25
2.10
1.29
0.89
1.80
1.18
2.29
App.
Effic.
0.99
0.99
1.00
0.99
0.99
0.99
0.99
1.00
0.99
0.99
0.99
0.99
0.99
0.99
0.99
Spray Drift
(1)
0.0087
Airblast
0.0049
Ground
0
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.0049
Ground
App.Date
15-Apr
1-Apr
3-Apr
1-Apr
1-Apr
1-Jun
15-Jul
17-Jul
20-Aug
1-Apr
15-Mar
1-Mar
1-Apr
1-Mar
1-May
Interval between applications
(days)
1
31
62
2
31
3
4
5
6
(1) Spray drift load estimated using Ag-Drift.
I.E.6 Page 6
-------
c. Region C (Arid/Semiarid West): Application Parameters
Chemical
AzinphosMet
iyi
Chlorpyrifos
Diazinon
Methidathion
Naled
DDVP (Naled
deqradate)
3hosmet
Chlorpyrifos
Dimethoate
Malathion
MethylParath
on
Dhosmet
AzinphosMet
lyl
Chlorpyrifos
Diazinon
PRZM
scenario file
lame
CAalmondC
CAalmondC
CAalmondC
CAalmondC
CAalmondC
CAalmondC
CAalmondC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAfruitC
CAfruitC
CAfruitC
Crop/Use
Almonds,
walnuts
Almonds,
walnuts
Almonds,
walnuts
Almonds,
walnuts
Almonds,
walnuts
Almonds,
walnuts
Almonds,
walnuts
Alfalfa
Alfalfa
Alfalfa
Alfalfa
Alfalfa
Apples, pears
Apples, pears
Apples, pears
App. Meth. llncorp.
(CAM) Depth
|(cm)
2
Air29%, Grd71%
2
Air 8%. Grd 92%
2
Air21%, Grd 79%
2
Air 8%. Grd 92%
2
AirO%, Grd 100%
2
2
Air 7%, Grd 93%
2
Air85%. Grd 15%
2
Air80%, Grd 20%
2
Air83%. Grd 17%
2
Air88%, Grd 12%
2
Air80%, Grd 21%
2
Air 6%, Grd 94%
2
Air 8%. Grd 92%
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
App. Rate
1.73
1.89
2.08
1.08
1.78
0.36
Naled*0.2
3.17
0.63
0.39
1.26
0.93
0.8
1.16
1.46
1.67
App.
Effic.
0.99
0.99
0.99
0.99
0.99
1
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
Spray Drift lApp.
bate
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0
Deqradate
0.0087
Airblast
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.0087
Airblast
0.0087
Airblast
0.0087
12-Jul
1 0-May
11 -Jan
11 -Jan
18-Jan
18-Jan
22-Mar
8-Mar
8-Mar
22-Mar
7-Mar
8-Mar
24-May
8-Mar
25-Jan
nterval between applications
(days)
1
7
7
7
7
6
6
119
7
7
7
1
7
21
49
42
2
1
21
14
1
1
1
7
7
7
7
1
1
7
7
1
3
6
49
1
6
1
1
7
35
7
7
6
6
28
21
6
4
1
7
6
7
6
6
7
126
49
7
7
7
35
28
154
5
F^
III.E.6Page7-
-------
Chemical
Dimethoate
Vlethidathion
Phosmet
Chlorpyrifos
Diazinon
Dimethoate
Methidathion
Maled
DDVP
3hosmet
Chlorpyrifos
DisulfotonT
Vlalathion
PRZM
scenario file
lame
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAfruitC
CAtomatoC
CAtomatoC
CAtomatoC
Crop/Use
Apples, pears
Apples, pears
Apples, pears
Peaches,
apricots
Peaches,
apricots
Peaches,
apricots
Peaches,
apricots
Peaches,
apricots
Peaches,
nectarines,
apricots
Peaches,
apricots
Asparagus
Asparagus
Asparagus
App. Meth.
(CAM)
Air1%, Grd99%
2
Incorp.
Depth
(cm)
0
AirO%, Grd100%
2| 0
AirO%, Grd100%
2| 0
Air 15%, Grd85%
2
0
Air1%, Grd99%
2
0
Air 3%, Grd97%
2
0
AirO%, Grd100%
2
0
Air 3%, Grd97%
2
0
AirO%,Grd100%
2
0
AirO%, Grd100%
2
0
Air 2%, Grd98%
2| 0
Air 51%, Grd49%.
2L 0
Air 67%, Grd33%
2| 0
Air 46%. Grd54%
App. Rate lApp.
Effic.
0.64
1.28
3.35
2.03
2.34
4.01
1.3
1.82
0.36
Naled*0.2
(RED)
3.09
0.72
1.18
1.11
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
1
0.99
0.99
0.99
0.99
Spray Drift
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0.0087
Airblast
0
Degradate
0.0087
Airblast
0.055
Aerial
0.055
Aerial
0.055
Aerial
App.
Date
18-Apr
1 8-Jan
17-May
25-Jan
22-Nov
5-Jun
18-Jan
4-Jan
4-Jan
31 -May
5-Jul
9-Aug
6-Jun
Interval between applications
(days)
1
1
7
14
1
1
1
42
1
1
7
21
28
1
2
1
28
35
6
14
1
280
12
12
7
7
14
1
3
20
7
21
318
14
1
14
1
1
21
42
14
13
4
28
7
28
1
7
1
1
1
1
14
35
7
7
5
0
I.E.6 Page 8
-------
Chemical
Acephate
Methamidoph
os (acephate
degradate)
Dimethoate
Vlalathion
^Jaled
DDVP
Diazinon
Dimethoate
Vlethamidoph
OS
ODM
Diazinon
Dimethoate
ODM
Acephate
PRZM prop/Use
scenario file I
name 1
CAtomatoC Legume
.
CAtomatoC
CAtomatoC
CAtomatoC
CAtomatoC
jeans)
.egume
)eans)
.egume
dry/succulent
jeans)
.egume
(dry/succulent
beans)
.egume
beans)
CAtomatoC Legume
CAtomatoC
CAtomatoC
CAtomatoC
CAtomatoC
beans)
Broccoli,
brassicas
Broccoli,
brassicas
Broccoli,
brassicas
Broccoli,
brassicas
CAtomatoC (Cantaloupe
CAtomatoC
DAtomatoC
CAtomatoC
Cantaloupe
Cantaloupe
Tomato
App. Meth.
(CAM)
2
Air 95%, Grd5%
2
Air 95%, Grd5%
2
Air 87%, Grd13%
2
Air 78%, Grd16%
2
Air 93%, Grd7%
2
Air 93%, Grd7%
Incorp.
Depth
(cm)
0
0
0
0
0
0
2| 0
Ground
2| 0
Air 54%, Grd46%
2| 0
Air 60%, Grd40%
2| 0
Air 45%, Grd55%
2| 0
Air 49%, Grd48%
2| 0
Air 69%, Grd31%
2| 0
Air 66%, Grd34%
2| 0
Air 58%. Grd42%
App. Rate
0.96
0.24
Aceph*0.2
5 (RED)
0.45
1.19
0.97
0.19
Maled*0.2
(RED)
1.12
0.4
1.67
0.56
0.38
0.54
0.42
0.91
App.
Effic.
0.99
1
0.99
0.99
0.99
1
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
Spray Drift
0.055
Aerial
0
Degradate
0.055
Aerial
0.055
Aerial
0.055
Aerial
0
Degradate
0.0049
Ground
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
App.
Date
2-Aug
4-Aug
Interval between applications
(days)
1
7
7
Aceph + 2
days
19-Jul
28-Jun
30-Aug
30-Aug
16-Aug
16-Aug
6-Sep
11 -Jan
17-May
2-Aug
24-Jul
9-Aug
14
35
7
7
1
14
20
35
7
1
1
1
2
7
7
7
7
7
7
1
7
1
244
69
6
1
20
3
14
14
21
1
1
1
1
7
1
1
1
1
1
1
4
7
7
14
6
13
13
1
28
20
1
1
7
1
6
5
6
I.E.6 Page 9
-------
Chemical
Vlethamidoph
os (acephate
degradate)
Chlorpyrifos
Diazinon
Dimethoate
Malathion
Methamidoph
OS
Chlorpyrifos
Dimethoate
vlalathion
MethylParath
on
Phosmet
Chlorpyrifos
Dimethoate
Malathion
PhorateT
Chlorpyrifos
Diazinon
Dimethoate
PRZM
scenario file
lame
CAtomatoC
CAtomatoC
CAtomatoC
CAtomatoC
CAtomatoC
CAtomatoC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAalfalfaC
CAcornC
CAcornC
CAcornC
CAcornC
CAgrapesC
CAgrapesC
CAqrapesC
Crop/Use
Tomato
Tomato
Tomato
Tomato
Tomato
Tomato
Alfalfa
Alfalfa
Alfalfa
Alfalfa
Alfalfa
FieldCorn
FieldCorn
FieldCorn
FieldCorn
Grapes
Grapes
Grapes
App. Meth.
(CAM)
2
Air 58%, Grd42%
Incorp.
Depth
(cm)
0
2| 0
Air 12%, Grd88%
2| 0
Air 4%, Grd96%
2[ 0
Air 71%, Grd29%
2| 0
Air 56%, Grd44%
2| 0
Air 51%, Grd49%
2| 0
Air 85%, Grd15%
2| 0
Air 80%, Grd20%
2| 0
Air 83%, Grd17%
2| 0
Air 88%, Grd12%
2| 0
Air 80%, Grd21%
2| 0
Air 18%, Grd82%
2| 0
Air 74%, Grd26%
2| 0
Air 89%, Grd11%
7| 2.5
AirO%,Grd100%
2| 0
Air 0%, Grd99%
2| 0
Air 0%, Grd99%
21 0
App. Rate
0.23
Aceph*0.2
5 (RED1
0.67
1.23
0.49
1.32
0.95
0.63
0.39
1.26
0.93
0.8
1.27
0.36
0.56
1,31
2.08
0.38
0.32
App.
Effic.
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
1
0.99
0.99
0.99
Spray Drift
0
Degradate
0.0049
Ground
0.0049
3round
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.055
Aerial
0.0049
Ground
0.055
Aerial
0.055
Aerial
0.85
Fraction in
upper 2 cm
0.0012
Vineyard
0.0012
Vineyard
0.0012
App.
Date
11-Aug
Interval between applications
(days)
1
1
Aceph + 2
days
12-Jul
8-Mar
. 5-Jul
26-Jul
12-Jul
8-Mar
8-Mar
22-Mar
7-Mar
8-Mar
17-May
13-Mar
22-Mar
3-May
7-Mar
17-May
17-Jul
21
56
14
1
14
7
7
7
1
7
21
1
1
14
1
83
1
2
20
1
14
7
6
21
7
7
7
1
1
7
1
13
14
1
1
1
3
1
20
7
7
1
21
35
7
7
6
6
14
1
133
7
6
1
1
4
6
1
49
21
13
21
126
49
7
7
7
14
90
7
7
1
1
1
5
0
-
III.E.6 Page TO
-------
Chemical
Walathion
Naled
DDVP
Chlorpyrifos
Methamidoph
OS
Naled
DDVP
ODM
PhorateT
PRZM
scenario file
aame
CAgrapesC
CAgrapesC
CAgrapesC
CAsugarbeet
C
CAsugarbeet
i*-»
CAsugarbeet
^
CAsugarbeet
r\
of
CAsugarbeet
^/
CAsugarbeet
>-\
Crop/Use
Grapes
Grapes
Grapes
Sugarbeet
Sugarbeet
Sugarbeet
Sugarbeet
Sugarbeet
Sugarbeet
App. Meth.
(CAM)
Incorp.
Depth
(cm)
Air 0%, Grd99%
2| 0
Air 6%, Grd94%
2| 0
Air 6%, Grd94%
2| 0
Air 6%, Grd94%
2
0
Air 78%, Grd22%
2
0
Air88%,Grd12%
2
0
Air 91%, Grd9%
2
0
Air 91%, Grd9%
2
0
Air 88%, Grd12%
7
2.5
Air 2%, Grd98%
App. Rate
32.37
0.75
0.15
Naled*0.2
(RED)
0.69
0.82
1.13
0.23
NJaled*0.2
(RED)
0.49
0.27
App.
Effic.
0.99
0.99
0.99
0.99
0.99
0.99
0.99
0.99
1
Spray Drift
Vineyard
0.0012
Vineyard
0.0012
Vineyard
0
Degradate
0.055
Aerial
0.055
Aerial
0.055
Aerial
0
Degradate
0.055
Aerial
0.85
Fraction in
uooer 2 cm
App.
Date
19-Jun
21-Jun
21-Jun
17-Mar
10-May
18-Sep
18-Sep
19-Apr
10-Apr
Interval between applications
(days)
1
1
28
28
70
84
1
1
1
1
2
1
14
14
21
7
1
1
6
1
3
1
7
7
21
7
1
1
133
1
4
1
28
28
7
49
1
1
14
1
5
3
(1) Spray drift load estimated using Ag-Drift.
I.E.6Page11
-------
d. Region D (Northeast/ North Central): Application Parameters
Chemical
AzinphosMet
ivl
Dimethoate
Chlorpyrifos
Phorate+
deqradates
Ferbufos+
degradates
Chlorpyrifos
PRZM
scenario file
name
MNsugarbeet
-\
_>
MNsugarbeet
-/
MNsugarbeet
-/
VINsugarbeet
MNsugarbeet
i"\
>j
NDwheatC
Crop/Use
Potato
Potato
Sugar beet
Sugar beet
Sugar beet
Wheat
App. Meth.
(CAM)
2
Aerial/ foliar
2
Aerial foliar
4
Ground/ plant;
gen w/ incorp
7
Ground/ plant
7
Ground/ plant
2
Aerial/ foliar
Incorp.
Depth
[cm)
0
0
5
2
2
0
App. Rate
0.53
0.30
1.39
1.14
2.19
0.56
App.
Effic.
0.99
0.99
.0.99
1
1
0.99
Spray Drift
0.055
Aerial
0.055
Aerial
0.0049
Ground
0.85
Fraction in
upper 2 cm
0.85
Fraction in
jpper 2 cm
0.055
Aerial
App.
Date
31-Jul
31-Jul
10-May
10-May
10-May
3-Jul
Interval between applications
(days)
1
2
3
4
5
6
(1) Spray drift load estimated using Ag-Drift.
I.E.6Page12
-------
e. Region E (Humid Southeast): Application Parameters
Chemical
[Terbufos +
Residues
Chlorpyrifos
Acephate
y/lethamidoph
os (Acephate
degradate)
Dimethoate
3horate +
Residues
Tribufos
Iisulfoton +
esidues
cephate
ethamidoph
os (Acephate
degradate)
Chlorpyrifos
PRZM
scenario file
lame
NCcornEC
NCcornEC
NCcottonC
NCcottonC
NCcottonC
NCcottonC
MCcottonC
NCcottonC
NCpeanutC
sJCpeanutC
NCpeanutC
Crop/Use lApp. Meth.
KCAM)
Corn
Corn
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
3eanut
Peanut
3eanut
7
n-furrow
2
Ground/ broadcas
>efore wheel
2
Broadcast
2
acephate degr
2
Broadcast
8
Banded
2
Broadcast
7
Banded
2
Aerial or ground/
jroadcast
2
acephate degr
2
Incorp.
Depth
(cm)
2.5
0
tor
0
0
0
1.27
0
2.5
0
0
0
Banded
App. Rate
1.27
1.30
0.30
0.07
aceph*0.2
5
0.11
1.00
0.51
0.73
0.52
0.13
aceph*0.2
5
0.70
App.
Effic.
1
0.99
0.99
0.99
0.99
1
0.99
1
0.99
1
0.99
Spray Drift
0.85
Frac in top
2 cm
0.0049
Ground
0.0049
Ground
0
0.0049
Ground
0
No drift
0.0049
Ground
0.85
Frac in top
2 cm
0.0049
Ground
0
0.0049
Ground
App.
Date
17-Apr
17-Apr
11-Jun
13-Jun
Off-set,
2-da t1/2
1-May
10-May
19-Oct
10-May
25-May
27-May
Off-set,
2-da 11/2
7-Jul
Interval between applications
(days)
1
41
2
3
4
5
3
I.E.6Page13
-------
Chemical
Phorate +
Residues
Acephate
Methamidoph
os (Acephate
deqradate)
Chlorpyrifos
PRZM
scenario file
name
NCpeanutC
NCtobaccoC
NCtobaccoC
NCtobaccoC
Crop/Use
Peanut
Tobacco
Tobacco
Tobacco
App. Meth.
(CAM)
7
3anded
2
Ground
Droadcast
2
Ground
aroadcast
2
Aerial or ground/
broadcast
Incorp.
Depth
(cm)
2.5
0
0
0
App; Rate
1.00
0.83
0.21
aceph*0.2
5
2.55
MASS
(1996)
App.
Effic.
1
0.99
1
. 0.99
fc*
Spray Drift
0.85
~rac in top
2 cm
0.0049
Ground
0
0.0049
Ground
App.
Date
18-May
30-Jun
2-Jul
16-May
Interval between applications
(days)
1
2
3
4
5
5
(1) Spray drift load estimated using Ag-Drift.
I.E.6 Page 14
-------
f. Region F (Lower Midwest): Application Parameters
Chemical
Chlorpyrifos
VlethylParath
on
Chlorpyrifos
Dimethoate
Phostebupiri
n
Ferbufos +
degradates
Acephate
Vlethamidoph
os (acephate
Degradate)
Chlorpyrifos
Dicrotophos
Dimethoate
Vlalathion
Malathion
PRZM
scenario file
name
TXalfalfaC
TXalfalfaC
TXcornC
TXcornC
TXcornC
FXcornC
FXcottonC
FXcottonC
FXcottonC
rXcottonC
FXcottonC
TXcottonC
TXcottonC
Crop/Use
Alfalfa
Alfalfa
Corn
j-%
Uorn
Corn
Corn
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
App. Meth.
(CAM)
2
2
\
2
7
7
2
2
Prairie / TX
Prairie / TX
Prairie / TX
Prairie / TX
Prairie / TX
Incorp.
Depth
(cm)
0
0
5
0
2.5
2.5
0
0
0
0
0
0
0
Appl. Rate
0.61
0.21
0.84
0.48
0.09
0.91
0.63
0.16
acephate*
0.25
0.71
0.16
0.27
1.13
1.13
App.
Effic.
0.99
0.99
1
0.99
1
1
0.99
1
0.99
0.99
0.99
0.99
0.99
Spray Drift
0.055
Aerial
0.055
Aerial
0.0049
Ground
0.055
Aerial
0.85
Fraction in
upper 2 cm
0.85
-raction in
upper 2 cm
0.0049
Ground
0
0.055
0.0049
Ground
0.0049
Ground
0.0049
Ground
0.055
Aerial
App.
Date
16-Jun
16-Jun
9-Apr
1-Jul
9-Apr
9-Apr
1-May
3-May
15-Jun
1-May
1-May
15-May
6-Jun
nterval between applications
(days)
1
20
20
31
23
23
22
2
22
3
22
4
22
5
22
6
I.E.6Page15
-------
Chemical
PRZM
scenario file
name
Crop/Use
App. Meth.
(CAM)
Incorp.
Depth
(cm)
Appl. RatelApp.
Effic.
Spray Drift
App.
Date
Interval between applications
(days)
1 f P f P f
Phorate + TXcottonC
degradates
Cotton
Ground/ plant
2.5 0.49 1 0.85 13-Apr
Fraction in
upper 2 cm
Tribufos
Chlorpyrifos
Dimethoate
TXcottonC
TXsorghumC
TXwheatC
Cotton
Sorghum
Wheat
2
Air/ Harvest
2
Aerial/ foliar
Aerial/
2
foliar
0 0.57
0 0,
0 0
.49
.31
0.99
0.99
0.99
Aerial
Aerial
Aerial
0.055
0.
055
0.055
1-Nov
2-May
8-Nov
(1) Spray drift load estimated using Ag-Drift.
I.E.6Page 16
-------
g. Region G (Mid-South): Application Parameters
Chemical
Chlorpyrifos
Dimethoate
Phostebupiri
n
Ferbufos +
Degradates -
Acephate
Methamidoph
os (acephate
deqradate)
Acephate
Methamidoph
os (acephate
deqradate)
Dicrotophos
Dicrotophos
Dimethoate
Dimethoate
vlalathion
PRZM
scenario file
lame
MScornC
VIScornC
MScornC
MScornC
MScottonC
MScottonC
MScottonC
MScottonC
MScottonC
MScottonC
MScottonC
MScottonC
MScottonC
Crop/Use
Corn
Corn
Corn
Corn
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
App. Meth.
(CAM)
4
Ground plant
2
Aerial foliar
7
Ground plant
7
Ground plant
2
Ground/
plant-foliar
2
Ground/
slant-foliar
2
Aerial/ foliar
2
Aerial/ foliar
2
Ground/ foliar
2
Aerial/ foliar
2
Ground/ foliar
2
Aerial/ foliar
2
Incorp.
Depth
(cm)
5
0
2.5
2.5
0
0
0
0
0
0
0
0
0
App. Rate
0.84
0.48
0.09
0.91
0.39
0.10
acephate*
0.25
0.39
0.10
acephate*
0,25
0.30
0.30
0.29
0.29
0.97
Appl.
Effic.
0.99
0.99
1
1
0.99
1
0.99
1
0.99
0.99
0.99
0.99
0.99
Spray Drift
0.0049
Ground
0.055
Aerial
0.85
Fraction in
upper 2 cm
0.85
Fraction in
upper 2 cm
0.0049
Ground
0
0.055
Aerial
0
0.0049
Ground
0.055
Aerial
0.0049
Ground
0.055
Aerial
0.0049
App.
Date
27-Mar
23-Jun
27-Mar
27-Mar
6-May
8-May
24-Jun
26-Jun
1-May
1-Jul
15-Jun
8-Jul
1-May
Interval between applications
(days)
1
19
2
19
3
4
5
3
III.E.6 Page 17
-------
Chemical
Malathion
Methamidoph
OS
PRZM
scenario file
lame
MScottonC
MScottonC
MethylParath MscottonC
ion
MethylParath MScottonC
ion
Phorate + MScottonC
Degradates
Profenofos MScottonC
Tributes MScottonC
Disulfoton + MScottonC
Degradates
MethylParath MSsoybeanC
ion
1(1) Spray drift load estimated
Crop/Use
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Cotton
Soybean
usina Aa-Drift.
App. Meth. Incorp.
(CAM) Depth
(cm)
Ground/ foliar
2 0
Aerial/ foliar
2 0
Aerial/ foliar
2 0
Ground/ foliar
2 0
Aerial/ foliar
7 2.5
Ground/ plant
7 2.5
Ground/ plant
2 0
Air/ Harvest
2 0
Ground/ foliar
2 0
Aerial/ foliar
App. Rate Appl.
Effic.
0.97 0.99
0.42 0.99
0.43 0.99
0.43 0.99
0.68 . 1
0.95 1
0.75 0.99
0.82 0.99
0.51 0.99
Spray Drift
Ground
0.055
Aerial
0.055
Aerial
0.0049
Ground
0.055
Aerial
0.85
Frac in top
2cm
0.85
Frac in top
2cm
0.055
Aerial
0.0049
Ground
0.055
Aerial
App.
Date
27-Jun
1-Jul
Interval between applications
(days)
1
19
2
19
3
19
15-Jun
4-Jul 19 19
6-May
15-Jun
2-Sep
23-May
31-Aug
4
19
5
5
l.E.6 Page 18
-------
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