[Federal Register: March 13, 2007 (Volume 72, Number 48)]
[Notices]
[Page 11411]
[DOCID:fr13mr07-90]

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SECURITIES AND EXCHANGE COMMISSION

[Release No. 34-55415; File No. SR-BSE-2006-03]

Self-Regulatory Organizations; Boston Stock Exchange, Inc.; Order
Granting Approval of Proposed Rule Change as Modified by Amendment No.
1, Relating to the Treatment of Limit Orders That Are Submitted to the
Boston Options Exchange During a Price Improvement Period

March 7, 2007.
    On December 8, 2006, the Boston Stock Exchange, Inc. (``BSE'' or
``Exchange'') filed with the Securities and Exchange Commission
(``Commission'') a proposed rule change pursuant to Section 19(b)(1) of
the Securities Exchange Act of 1934 (``Act''),\1\ and Rule 19b-4
thereunder,\2\ to amend the rules of the Boston Options Exchange
(``BOX'') relating to the treatment of Limit Orders that are submitted
to the BOX during a Price Improvement Period (``PIP''). On January 4,
2007, the BSE filed Amendment No. 1 to the proposal. The proposed rule
change, as amended, was published for comment in the Federal Register
on January 16, 2007.\3\ The Commission received no comments on the
proposal. This order approves the proposed rule change as modified by
Amendment No. 1.
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    \1\ 5 U.S.C. 78s(b)(1).
    \2\ 17 CFR 240.19b-4.
    \3\ See Securities Exchange Act Release No. 55050 (January 5,
2007), 72 FR 1786 (SR-BSE-2006-03) (``Notice'').
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    The Commission finds that the proposed rule change is consistent
with the requirements of the Act and the rules and regulations
thereunder applicable to a national securities exchange \4\ and, in
particular, the requirements of Section 6(b)(5) of the Act.\5\
Specifically, the Commission believes that the proposed rule change is
consistent with the Act because it makes explicit how unrelated Limit
Orders \6\ in the same series as a PIP Order, submitted to the BOX
during the PIP,\7\ are treated, and specifies the circumstances under
which Improvement Orders are not accepted by the BOX Trading Host.\8\
The Commission believes that these rule amendments are reasonable and
consistent with the Act, and should help clarify for investors and
market participants how their orders are executed in various
situations.\9\
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    \4\ In approving this proposed rule change, the Commission has
considered the proposed rule's impact on efficiency, competition,
and capital formation. 15 U.S.C. 78c(f).
    \5\ 15 U.S.C. 78f(b)(5).
    \6\ An ``unrelated order,'' generally, is a non-Improvement
Order entered into the BOX market while a PIP is in progress. See
paragraph (a) of Section 18 of Chapter V of the BOX rules. An
``Improvement Order,'' generally, is an order submitted to a PIP to
compete for a ``PIP Order'' (a customer order submitted to the PIP
for price improvement). See paragraph (e)(i) of Section 18 of
Chapter V of the BOX Rules.
    \7\ As detailed in the Notice, certain unrelated Limit Orders on
the same side of the market as a PIP Order terminate the PIP
prematurely, while certain unrelated Limit Orders on the opposite
side of the market immediately execute against the PIP Order (and
allow the PIP to continue if the PIP Order has not been filled). The
proposal clarifies the circumstances in which these early
terminations and immediate executions take place, as well as the
rules governing the prices that the PIP Order and unrelated Limit
Order receive in each of these circumstances.
    \8\ The proposal specifies that the BOX Trading Host does not
accept Improvement Orders that would lock or cross the BOX Book.
    \9\ In addition, the Commission notes that BSE is currently
obligated to provide certain reports to the Commission that provide
data about BOX-Top and Market Orders that terminate the PIP
prematurely, as well as BOX-Top and Market Orders that immediately
execute against a PIP Order. BSE represents that it will provide the
same information for Limit Orders that terminate the PIP prematurely
or immediately execute against a PIP Order.
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    It is therefore ordered, pursuant to Section 19(b)(2) of the
Act,\10\ that the proposed rule change (SR-BSE-2006-03) as modified by
Amendment No. 1, be, and hereby is approved.
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    \10\ 15 U.S.C. 78s(b)(2).

    For the Commission, by the Division of Market Regulation,
pursuant to delegated authority.\11\
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    \11\ 17 CFR 200.30-3(a)(12).
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Florence E. Harmon,
Deputy Secretary.
[FR Doc. E7-4503 Filed 3-12-07; 8:45 am]

BILLING CODE 8010-01-P


important factor to consider is that core locations be distributed throughout the field in such a
manner that a strong conceptual model can be developed.  This can be accomplished by locating
the cores randomly, along a grid, or stratifying them according to some predetermined criterion.
The grid may be oriented perpendicular or parallel to the ground-water flow field.  The field may

35
be segmented into sectors, gridded and cores randomly located in each sector.  If piezometers
will be installed at core locations, these locations should be located at or near the corners of the
study site.
Coring methods should be selected based on consideration of the anticipated textures of the
vadose and saturated zones, the anticipated borehole depth, stability of the borehole, and ease of
collection of samples for analysis.  Drilling methods appropriate for these considerations are
described in the ASTM standards manual.
3.23 Field Testing
The description or prediction of processes which influence pesticide dissipation, specifically
leaching, in the field requires an understanding of infiltration, recharge, and internal drainage
(water redistribution).  Thus there is a need to characterize soil hydraulic properties, such as soil
water content, matric potential vs. soil water content (water characteristic function) relationships
and hydraulic conductivity.  Because soils in a field are typically heterogeneous, solute transport
is controlled by properties which vary both spatially and temporally, and these are also often
scale dependant.  Therefore, it is important that these parameters be measured in the field.
In these two to five acre study sites, we recommend that the saturated and unsaturated hydraulic
conductivity be measured at a minimum of six locations dispersed across the study site (and
indicated on the site base map) to take into account field variability of soils.  If significant
variability in hydraulic conductivity is evident, then measurements should be made in additional
locations to further define the range of variability across the site.  In general, measurements are
made for at least two depth horizons at each measurement location - one at the soil surface and
for each soil horizon below the surface to a depth of six feet.  The soil water content should also
be measured at these sites from the surface to the water table.  These data will be correlated with
the water characteristic function determined in the lab and the matric potential will be estimated
for these locations.  The matric potential indicates the direction of water movement in the vadose
zone.  The field determined soil water content will also be correlated with the hydraulic
conductivity and compared to the lab results from the soil cores.  This will provide insight into
how well the results of the lab tests represent actual conditions in the field.  Consideration should
also be given to developing breakthrough curves to determine dispersivity and the likelihood for
preferential flow and to estimate an effective porosity for soil samples.
3.24  Preservation and Transportation of Formation Samples
ASTM provides guidance for preserving and transporting soil samples for analysis.  Although
some flexibility in these procedures might be necessary due to the practical considerations in
sampling a farm field, certain procedures should be followed in every case.  The field personnel
should follow all relevant Department of Transportation (DOT) and International Air Transport
Association (IATA) hazardous materials and dangerous goods regulations concerning the
shipping of dry ice.  These samples should be sent by overnight mail the day they are collected,
or kept frozen until they arrive at the laboratory.

36
3.25  Quality Assurance and Quality Control Procedures
Procedures for ensuring the quality of all soil samples and the data derived from those samples
are an integral part of the exploratory coring program.  Mason (1983) and Barth et al. (1989)
present details on quality assurance for soil and formation sampling activities.  Good laboratory
practices relevant to field investigations should be followed.
All soil core logs and subsurface descriptions recorded during the drilling operation should be
included in the Site Characterization Report.  State or local regulations concerning the permitting
and/or documentation of exploratory coring activities should be followed.  Chain-of-custody
forms should be prepared and archived for all subsurface samples, and subsurface samples that
are not destroyed by analytical procedures should be retained as reference samples for the
duration of each study.
3.26  Test Pit Excavation
The Agency views the completion of test pit excavations during the initial phases of the site
characterization process as a quick and inexpensive way to assess the heterogeneity of a site and
the potential for preferential flow.  The 1998 Scientific Advisory Panel (SAP) identified the
presence of preferential flow as a critical element to be assessed in the site selection/site
characterization process.  If a pesticide is to be used in an area dominated by preferential flow
(e.g. in a karstic region or with extensive tile drainage) then site characterization should evaluate
this process and consider sites with documented preferential flow.  The completion of test pits at
the subject site is a quick and inexpensive way to assess whether preferential flow is likely (at
least in the near surface) at a site.  Unusual conditions which may prove problematic for a
Prospective Ground-Water Study ($"!" restrictive layers) can quickly be identified and result in
significant cost savings.  Test pits may also be considered during the course of the study when
unusual conditions are noted.  Test pits should not be located within the active monitoring area
but should be located in close proximity to the area of pesticide application ($"!" immediately
adjacent to the site or within a control plot).
Test pit excavations are particularly useful in characterizing the lateral extent or thickness of
low-permeability layers noted during soil survey and exploratory boring activities or in
identifying dominant patterns at a site (Mason, 1983).  Soil structure or other features that may
result in significant preferential flow should be noted and reported.  Such features are common
and should be investigated through use of test pits when considering a site.  The excavation
should be located adjacent to or near the area of the site where the compounds of interest are to
be applied and monitored.  The locations of the test pits should be indicated on the base map.
The walls of the test pits should be described using methodology and nomenclature which is
consistent with the Soil Survey Manual (Soil Survey Division Staff, 1993), Soil Taxonomy (Soil
Survey Staff, 1975), and Keys to Soil Taxonomy (Soil Survey Staff, 1992).  Photographs of pit
walls could also be considered.
Field workers should take care when entering a test pit to characterize soil properties. All test pit
activities should be conducted under the supervision of an Occupational Safety and Health

37
Administration (OSHA) required “competent person”.  OSHA standards state that test pits
should not be excavated to deeper than five feet unless a shoring system (!"#" trench box or
trench shield) is installed to support the pit walls.  However, since the stability of pits five feet
deep and shallower can also vary with soil texture and moisture, safety precautions should be
considered in these scenarios as well.  Proper abandonment procedures for test pits should be
undertaken and documented in the First Quarterly Report.
3.27  Abandonment of Soil Core Holes
Characterization of the shallow saturated zone requires the installation of at least four
piezometers.  Some of the cores drilled for soil characterization may be converted into
piezometers.  The holes created by soil coring that are not converted to piezometers should be
properly abandoned prior to the application of the compounds of interest.  Guidance on proper
abandonment of soil coring locations may be found in Aller et al. (1990) and American Water
Works Association (1984).  Boring abandonment procedures should also comply with any state
or local regulations for agricultural fields. If additional fill material is required to complete the
abandonment process, “pesticide-free” soil should be used.
3.3 SATURATED ZONE INVESTIGATION
A limited investigation of the saturated flow regime should be conducted for each study site.
This information is needed to develop the conceptual model and to interpret monitoring data.
The following sections describe the recommended procedures for characterizing the ground-
water flow characteristics of the aquifer.  These procedures include collecting hydraulic head
data and conducting pumping tests and/or slug tests.  The data derived from these activities are
then used to estimate the direction of ground-water flow, the hydraulic conductivity of the
aquifer, and the ground-water velocity at the study site.
3.31  Hydraulic Head
Piezometers should be installed at the site to measure the hydraulic head.  If done
simultaneously, piezometers may be placed in the same borehole where the exploratory soil cores
were collected, to save resources.  At least four piezometers should be installed at the corners of
the study site to establish the water-table surface.  These piezometers should remain in place for
the duration of the study so that these simple measurements can continue to be made.  Since
suitable sites for ground-water monitoring studies should exhibit low topographic relief, small
errors in surface elevation measurements can seriously impact the interpretation of subsurface
conditions.  Therefore, care should be taken to measure and record elevation data accurately.  A
small cut or indelible mark should be placed on the piezometer well casing for use as a measur-
ing point (MP), and this point should be surveyed relative to the local U.S. Geodetic Vertical
Datum.  The location and height of this point should be measured to an accuracy of plus or minus
0.01 foot.
Procedures for measuring depth to water in monitoring wells are detailed in ASTM Standards.
Initial measurements of water levels should not be collected until after the piezometer or well has
had time to stabilize from the effects of construction and development activities.  Piezometer

38
locations should be specified on the base map, and initial water level data should be presented on
a map in the Site Characterization and Monitoring Plan Report.
3.32  Direction of Ground-Water Flow and Hydraulic Gradient
A map of the potentiometric surface of the surficial aquifer should be prepared for each study
site.  This map should use the site base map for location information and should include the
locations of piezometric head measuring points.  Contour lines representing equal hydraulic head
should be constructed.  Methods for constructing water-table maps and estimating hydraulic
gradient and ground-water flow direction from these maps are provided in Freeze and Cherry
(1979).
3.33  Hydraulic Conductivity
The hydraulic conductivity of an aquifer controls the rate at which ground water flows under a
given hydraulic gradient.  The velocity of the ground water can be used to approximate how long
it will take a conservative tracer (or pesticide) to travel beyond the test site boundaries.
Hydraulic conductivity is typically measured in the field by means of slug tests or pumping tests.
Slug tests should be conducted at locations where the soil cores indicate very low hydraulic
conductivity aquifer materials.  A pumping test under these conditions is usually not possible
because the yield of the aquifer is too small to collect sufficient data to analyze using typical
methods.  Slug tests sample a very small region around the well and the results only represent the
aquifer properties in that region.  Therefore, they are of limited value and one should be done at
every well.  Pumping tests should be used when the hydraulic conductivity values are large
enough to collect sufficient data to analyze using typical methods.  Pumping tests sample a much
larger region of the aquifer and give a more representative hydraulic conductivity value for the
aquifer.  Also, fewer pumping tests would have to be conducted because they do sample a much
larger portion of the aquifer.  Methods for conducting and analyzing slug tests and pumping tests
are provided in Freeze and Cherry (1979), Walton (1987) and Fetter (1988).  The results and
interpretations of all slug tests and pumping tests should be included in the Site Characterization
Report.
3.34  Background Water Quality
Basic data should be collected to establish the background quality of ground water, irrigation
water and precipitation at the study site.  Analyses should include major ions (dissolved oxygen,
alkalinity, etc.), major nutrients (nitrate, nitrite, ammonia, organic nitrogen, and phosphate),
temperature, electrical conductivity and pH.  Additionally, water should be analyzed for the test
compound (to ensure that there are no residues, and to check the analytical method) and the
tracer compound (typically bromide).
If the irrigation source is a well within a quarter mile of the test plot, the study director should
determine if pumping this well has any effect on the water table below the test site.  This can be
accomplished by using a data logger probe in the monitoring well nearest the irrigation well, and
monitoring any drawdown of the depth to water when the irrigation well pump is turned on.

39
Ensure that the irrigation well is run long enough to ensure communication with the underlying
aquifer.
3.4  CONCEPTUAL MODEL
Site characterization data are analyzed and interpreted to produce a three-dimensional
representation of the characteristics of the study site.  The site-specific conceptual model should
include graphical displays of interpreted hydrogeologic characteristics that illustrate the
relationship between soil and hydrogeologic features.  The conceptual model should be discussed
with reference to graphs, figures, and maps and the data collected during site characterization.
The discussion should integrate site hydrogeology, surface hydrology, and historical climatic
data.  The minimum graphical tools and analyses needed to develop the model are described in
the following sections.
3.41  Soils and the Vadose Zone
The results of the soil analyses including preliminary surface investigations and NRCS
information, exploratory coring program, and test pit excavation should be analyzed and
integrated.  At a minimum, the following are needed to interpret these data:
·
At least two stratigraphic cross sections (or fence diagrams) for each study site, one
parallel to the direction of ground-water flow and one perpendicular to ground-water
flow,
·
A detailed map of surface soils (1:100 to 1:1,000),
·
Graphs or tables of particle-size distribution vs.  depth for each core,
·
Graphs or tables of matric potential head vs.  depth and soil water content,
·
Graphs or tables of hydraulic conductivity vs.  soil water content,
·
Graphs or tables of organic matter content vs.  depth for each core,
·
Tables and/or graphs that display ranges of hydraulic conductivity,
·
Ranges of bulk density and hydraulic conductivity values for significant subsurface
horizons,
·
An estimate of the amount of water needed for the tracer to reach ground water in two
years and
·
An estimate of travel time needed for the tracer and/or pesticide to reach ground water.

40
A brief discussion of the above information should identify areas in the study site (at the surface
or at depth) where variations in topography, soil texture, or other factors could cause differences
in recharge.  All data analysis techniques and the results of those techniques should be
documented in the Site Characterization Report.
3.42  Saturated Zone and Water Quality
The results of saturated zone investigations and background water quality analyses are used to
interpret the subsurface hydrogeology of the site.  At a minimum, the following are needed to
interpret these data:
·
Contour map of the water table surface indicating the direction of ground-water flow,
·
Analyses of slug tests and/or pump tests
·
Estimate of hydraulic gradient and flow velocity of the aquifer,
·
Comparison of the spatial distribution of hydraulic conductivity using data obtained from
laboratory and field investigations,
·
Graphical display of water quality data from the onsite wells, the irrigation source and
precipitation and
·
Sample chromatogram from an analysis of the test compound(s) and tracer in onsite
water.
These and other data analysis techniques and the results of those techniques should be
documented in the Site Characterization Report.  The discussion accompanying these data should
address water table fluctuations based on the collection of local historical data.  Regional
recharge and discharge areas should also be discussed, including nearby features such as
irrigation wells and canals that could influence the flow system.  The discussion should also
include a description of the variations in hydraulic conductivity, the presence of confining layers,
and the overall aquifer flow system at the site, using historical data where necessary.  Any
interferences identified when analyzing the water collected at the site should also be discussed.

41
CHAPTER 4 - MONITORING PLAN DESIGN
Once the site has been characterized, the variability of soil properties and the ground-water flow
system are understood, and a conceptual model developed, a monitoring plan can be designed
that is suited to the study site.  The number of wells and other sampling devices required to
provide a high degree of statistical certainty in the study results would likely prevent the
cooperating farmer from growing a crop on the field using standard agronomic practices, and
would make the study prohibitively expensive.  However, with a good conceptual model and a
reasonable number of sampling locations, monitoring data will be adequate to answer regulatory
questions.  The clear advantages of testing a pesticide in the field under conditions that as closely
as possible resemble those in which it will actually be used, as discussed in Chapter 1, outweigh
any disadvantages.  Additional tools such as lysimeters and computer models can provide useful
data to augment the field data obtained.  It is strongly recommended that studies be conducted
under FIFRA GLP, as described in 40CFR160.  Written standard operating procedures (SOP)
should be developed and maintained by the study director.
The compounds of interest (Chapter 2) will be monitored in surface soils, the vadose zone, and
the saturated zone.  A conservative tracer will be used to follow water movement through the
system and weather will be monitored throughout the study.  Aspects to consider, and minimum
data collection needs, are described in the following sections:
·
Setting Up
·
Soil Monitoring Plan
·
Soil Water Monitoring Plan
·
Ground-Water Monitoring Plan
Design decisions should be integrated into one Monitoring Plan Design Report for the
Prospective Ground-Water Monitoring Study.
4.1 SETTING UP
4.11  Agricultural Management Practices
Standard agricultural practices for the target crop and the intended use of the test pesticide should
be followed while conducting the Prospective Ground-Water Monitoring Study.  All pesticides,
fertilizers, and farming, maintenance, and sampling equipment should be stored away from the
study site so as to eliminate the possibility of contamination.

42
4.12  Irrigation
The following guidelines assume that leaching of the pesticide is being investigated at a site
selected because conditions exist at that site that are more likely to promote ground-water
vulnerability and will provide data on the leaching of the pesticide under those conditions.  Some
alterations may be approved in the irrigation scheme at selected sites when leaching at multiple
sites representing different levels of ground-water vulnerability is being investigated.  Irrigation
should be scheduled at regular intervals, as well as applied at critical periods in the growing
season, to meet the target water input.  The initial irrigation event should be scheduled to occur
within three days after the pesticide application, unless sufficient precipitation occurs during this
time.  Following the first irrigation event, dates should be established when additional water will
be applied to the field if monthly targets of total applied water are not reached as a result of
natural precipitation.  The schedule should be flexible enough to ensure that adequate water is
applied to meet the needs of the crop, particularly in critical moisture periods (such as the period
of tasseling through silking for corn, or during fruit development for orchard crops).  The
Monitoring Plan Design Report should indicate the irrigation method, rate, schedule, and
duration.  Actual dates of irrigation events should be documented and reported in the Final
Report.
Estimate target water requirement by month (for example:  120% of crop water demand or 120% of
historical rainfall data, whichever is greater).  However, it should be noted that the estimated target
water requirement for a specific study site may be much greater than 120% of crop water demand or
120% of historical rainfall data.  State agricultural agents should be consulted to determine an
appropriate target irrigation rate in order to ensure recharge of irrigation water to ground water.  For
example, historical irrigation efficiencies in the San Joaquin Valley of California are estimated at
60% for surface (flood) irrigation and 70% for sprinkler irrigation (DWR, 1983; Snyder et al., 1986;
California Agricultural Technology Institute, 1988).  These efficiencies translate to water application
rates of 167% and 143% of plant demand, respectively.  In addition, extensive agricultural areas in
California have been identified as vulnerable to ground water contamination due to the presence of
coarse soils and shallow ground water.  CA DRP has calibrated the LEACHM transport and fate
model to these conditions and has estimated concentrations of pesticides in ground water from
simulated water application of 167% of plant demand.  These values agree well with measured well
water concentrations (Spurlock, et al., 2006).  California indicated they have limited water
applications to 125% of plant demand to mitigate ground water contamination  for some
contaminants.  Attached as a reference are two example spreadsheets that were developed by the
California Department of Pesticide Regulation, Environmental Monitoring Branch to estimate
drainage from a prospective ground water study. These goals should be maintained at the study site
through each and every agronomic season starting from the initial pesticide application date
throughout the entire monitoring period for the study unless alternate goals are agreed to by the
Agency during the latter years of the study. Calculations for target water requirements should be
based on 20-year data distributions (crop, study site/region, rainfall, irrigation, etc).  Document
calculations, assumptions, and reference 20-year data used in determining target water demand.
Procedures used to determine the timing and amounts of water as a function of rainfall and other

43
climate conditions should be provided.  The type of irrigation system, the frequency of irrigation, and
the minimum amount of irrigation applied should conform with local agronomic practices for the
specific crop and study soil.  Consultation with state agricultural agents may be helpful in identifying
the most suitable sites and applicable agronomic practices for the study.  All irrigation events should
be conducted so as to minimize surface pooling and runoff while maximizing the potential for
infiltration.
4.13  Initial Post-Pesticide Application Irrigation Event
In general, the timing and rate of irrigation is more important during the initial days and weeks
after application than it is as the study progresses into the second year and beyond.  The
relationship between rainfall timing and intensity and pesticide leaching has been reported by a
number of researchers (Isensee et al, 1990; McLay et al., 1991, Shipitalo et al., 1990; Sigua et al.,
1993;1995).  Since rainfall is both spatially and temporally variable, it is necessary to supplement
rainfall so that a study can be conducted within a reasonable time period.  Therefore, it is
recommended that an initial irrigation be applied to the study area within three days after the
pesticide application.
After initial pesticide application, a minimum of 1.0 inch of natural rainfall or irrigation should
occur within 3 days and the application rate should be between 0.5 and 1.0 inches per hour.  The
first month’s targeted rainfall plus irrigation amounts should be divided into four periods of 7-8
days each, and at least one fourth of the target monthly water requirement should occur in each of
the four periods (apply additional irrigation water amounts in increments of 0.3 inches or greater
as needed to meet the total month’s targeted amount).
4.14  Irrigation After Initial Event
The intent of the Prospective Ground-Water Monitoring Study is to evaluate a pesticide’s
potential to contaminate ground water and to provide an idea as to the concentrations that could
be seen in ground water through normal agricultural activities.  It is therefore necessary that
enough water be added to the site so that ground water is recharged during the study.  Due to the
stochastic nature of precipitation, to rely strictly on precipitation may result in the study having to
be conducted for many years.  Thus irrigation can be applied to reduce the length of time that a
study may need to run.
Beginning with the second month after application, at least the target water requirement for the
specific month (as specified in Agency-approved Monitoring Plan Design report) should occur
either in the form of natural rainfall or applied as irrigation.  Irrigation does not have to be
applied when the crop is not present.  For example, irrigation should not be applied during winter
months when freezing would destroy irrigation equipment.  On occasion, at sites where
precipitation has fallen well below historical norms for months or longer, some irrigation water
might be applied during fallow months in order to meet the previously established water balance
targets.  Irrigation is not required at times when damage to the crop would occur (during times
when drying is essential).

44
Sprinkler irrigation is preferred except in instances where other crop-specific methods (flood
irrigation as an example) are required to assess movement under typical agronomic practices.
Documentation should be provided, including references and names, for such crop-specific
irrigation practices.
4.15  Mixing and Loading Area
The location of pesticide mixing and loading activities should be identified on the base map.
Ideally these activities should take place down gradient and down slope from the site to minimize
the possibility of point-source contamination.  Other activities that could take place in this area
include calibration of the sprayer equipment with water, sampling of the application (tank)
mixture, and sampling equipment cleaning.
4.16  Control Plot
To establish background ground water quality, at least one well should be placed hydraulically up
gradient of the field where the test pesticide will be applied.  Control plots should be planted and
maintained the same as the treated field.  Control wells should be sampled on the same schedule
as monitoring wells in the treated field.  The control area and control well location(s) should be
identified on the base map.
4.17  Decontamination Area
Prior to sampling soils or ground water, equipment should be cleaned to minimize the likelihood
of cross-contamination.  This should be done far enough away from the study site so that
activities and onsite disposal of rinsate will not affect study results.  The decontamination area
should be identified on the base map. Additionally, rinsate should not be disposed of in
“ecologically sensitive” areas, such as wetlands or down other wells.
4.18  Weather Station
Onsite climatic monitoring is essential in evaluating pesticide leaching relative to the timing and
magnitude of precipitation.  Precipitation data are also needed to determine the required amount
of monthly irrigation.  Daily rainfall amount and intensity, pan evaporation, and temperature data
are also key input parameters for several computer simulation models.  A variety of automated
weather stations and data logging equipment are commercially available that record daily
precipitation, pan evaporation, wind speed, solar radiation, minimum and maximum air
temperature, and soil temperature.  Special care should be taken to protect parts of the weather
station that can easily be damaged by birds and other animals, such as rain gauges and
evaporation pans.  The weather station should be located close to the test plot in an open,
exposed area without trees.

45
4.2  APPLICATION OF PESTICIDE AND TRACER
4.21  Pesticide
Decisions about pesticide application rates are made when the study scope is defined.
Application method, calibration procedures and the amount applied should be documented for
the test pesticide and reported in the Site Characterization and Monitoring Plan.  Only one
application of the pesticide should be made.  The tank mixture should be sampled and the
concentration confirmed.  The pesticide application rate should be verified using pan samplers,
shallow soil samples, application cards or other in situ collection devices.  Nominal and actual
application rates should be reported.
4.22  Tracer
A conservative tracer should be applied along with the test pesticide to provide information on
the direction and rate of movement of water through the vadose and saturated zones.
When selecting a tracer, the chemistry of the compound should be considered along with
potential sources of background interference, achievable detection limits, and potential losses due
to adsorption, volatilization, and plant uptake.  Bromide and chloride have typically been used to
trace the movement of soil water in agricultural studies.  Other tracers may be acceptable if
approved by EPA.
Appropriate tracer application rates should be determined prior to initiation of the study, taking
into consideration analytical methods and limits of detection and quantification, and
concentrations in background soil and water samples (higher background levels of bromide, for
example, at a study site can interfere with the ability to track the subsurface movement of the ion
unless a relatively high initial application rate is used).  Analytical methods, calibration
procedures and amount of tracer applied should be documented and reported in the Monitoring
Plan Design and Final Reports.  The tracer should only be applied once at the same time as the
initial pesticide application.
4.3  SOIL MONITORING PLAN
The primary purpose of soil sampling in these studies is to verify pesticide application rate and to
provide information on the dissipation of the compounds of interest in the zone of application,
and not to track the movement of the test compound through the subsurface.  Experience with
prospective studies over the past 10 plus years indicates little correlation between pesticide
detections in soil cores and detections in ground water.  Some subsurface soil samples are
collected early in the study to identify residues that remain in top meter of the soil column, above
the uppermost lysimeters.  Deeper vertical transport will be tracked using suction lysimeters and