Office of
Indiana State Chemist and Seed Commissioner
GROUND WATER PROTECTION
STATE OF INDIANA DRAFT GENERIC
PESTICIDE MANAGEMENT PLAN
COMPONENT 6 MONITORING
Introduction
The objective of an Indiana monitoring network will
be to sample selected wells in a manner that will provide a statistical
evaluation of trends in pesticide occurrence and trends in pesticide
concentrations in major aquifers of the State.
BASELINE MONITORING
Goals and Approach of the Indiana Baseline Monitoring
Network.
The purpose of the Indiana Baseline Monitoring Network
(Appendix C) is to develop a statistically valid basis for extrapolating
pesticide data from wells in the Indiana Baseline Monitoring Program
to evaluate aquifers throughout the state. The SMP monitoring
subcommittee has set the following parameters relative to the
development of a baseline monitoring network:
- Criteria for selecting chemical analytes to be
monitored.
- Standards for the inclusion of existing wells.
- Specifications for installing new wells.
- Number of water well samples to be collected
and analyzed each year.
- Selection of principal hydrogeologic settings
and significant subsettings in Indiana.
- Location and frequency of water well sampling
- Water sample handling and analysis.
The statistical analysis of data will be targeted
at detecting trends in the occurrence and quantity of pesticides
in ground water. In particular, the following questions will be
addressed:
(1) In any given year, which categories and (or)
subcategories of aquifers have occurrences and concentrations
of pesticides that are above a specified level of tolerance? The
level of tolerance may be specified by the State Chemist or any
other group authorized to set a limit on occurrences or concentrations
of pesticides in ground water.
(2) Has there been a statistically significant (95
percent confidence level) increase or decrease in the occurrence
and (or) concentration of pesticides in any of the categories
or subcategories of aquifers? If so are the differences associated
with a particular season?
The primary statistical procedure to be employed
in the modeling program is Analysis of Variance (ANOVA), and its
variant the t-test.
Criteria for selecting chemical analytes to be
monitored.
The following criteria were selected for determining
the significance of a pesticide active ingredient for inclusion
in a baseline monitoring network. Active ingredients which meet
three or more of the criteria receive a rank of one (1) priority
for inclusion in a baseline monitoring network. Active ingredients
which meet two (2) or more of the criteria receive a rank of two
(2) priority for inclusion in a baseline monitoring network. Active
ingredients which meet one or more of the criteria receive a rank
of three (3) priority for inclusion in a baseline monitoring network
(APPENDIX G.)
Previously canceled or suspended pesticide active
ingredients will not receive consideration as candidates for a baseline monitoring network.
- Ground water advisory statements present on product
label.
- Detection in ground water samples collected in
Indiana by government agencies.
- Detection in public water supply Safe Drinking
Water Act (SDWA) compliance samples.
- Active Ingredients currently registered for sale
or use in the state of Indiana.
- During three (3) of the last four (4) years,
active ingredient applied to >5% of IN corn acres.
- During three (3) of the last four (4) years,
active ingredient applied to >5% of IN soybean acres.
Standards for the inclusion of existing wells.
Public Supply Wells.
- Well record available (depth, diameter, screen/open interval,
date, etc.)
- Ability to sample raw water from specific location near
well head.
- *Avoid upgradient point source(s) of potential pesticide
contamination.
- Well in current use.
- Well survey/inspection re: drainage, grouting, history,
surface appearance, etc.
- Well is readily accessible.
- Wells screened in multiple aquifers excluded.
- Above ground well seal or pitless adapter.
Domestic Wells.
- Well record available (depth, diameter, screen/open interval,
date, etc.)
- Ability to sample raw water from specific location near
well head.
- *Not near point source of potential pesticide contamination.
- Well in current use.
- Well survey/inspection re: drainage, grouting, history,
surface appearance, etc.
- Well is readily accessible.
- Bored and dug wells excluded.
- Pitless adapter present.
Monitoring Wells.
- Well record available (depth, diameter, screen/open interval,
date, etc.)
- Ability to sample raw water from specific location near
well head.
- *Not near point source of potential pesticide contamination.
- Well continuously protected by locking cap.
- Well survey/inspection re: drainage, grouting, history,
surface appearance, etc.
- Well is readily accessible.
- Any type of steel casing OK.
- PVC or teflon casing OK if threaded joints.
Specifications for installing new monitoring wells.
- Drilled by Indiana licensed driller.
- Detailed well record, completion, and development information.
- Well elevations and coordinates (land surface and casing
top.)
- * Not near point source of potential pesticide contamination.
- Well survey/inspection re: drainage, grouting, history,
surface appearance, etc.
- Well is readily accessible.
- Materials:
- PVC casing, 2-inch diameter, Sch 40, threaded joints, 2.5
to 3.0 feet stickup.
- Steel protector casing, locking metal cap (all keyed alike),
painted bright.
- Steel protector casing cemented in place.
- PVC screen, commercially slotted, .020" slots, length
varies with well.
- End caps on top and bottom, 6-inch blank casing below screen.
- Vented end cap on top.
- Commercial bagged quartz sand filter pack
- Pressure grout annulus with bentonite grout.
- Bentonite chips or pellets on top of filter pack when feasible
before grouting.
- Drilling considerations:
- Minimum 4-inch ID hollow stem auger for shallow unconsolidated
wells.
- Minimum rotary with 6-5/8 inch bit for deeper wells.
- Drilling water source must be from a public water supply,
or other approved source.
- Development, for 2 hours or until clear to owner's
satisfaction.
- Other considerations:
- Consistent well numbering system (e.g., 55-1 and 55-2 for
first 2 wells in Morgan County).
- Provision for proper plugging of abandon holes and eventually
the wells.
- Monitoring well construction standards in 310 IAC 16-8-3
shall be followed at a minimum.
* indicate well siting criteria
Number of water well samples to be collected and
analyzed each year.
The SMP monitoring subcommittee determined approximately
1,600 water well samples could be collected during a calendar
year by IDEM OWM Ground Water Section personnel.
Quarterly sampling of each site is necessary in order
to account for seasonal variability. Thus, the monitoring network
will consist of a total of approximately 400 wells.
Selection of principal hydrogeologic settings
and significant subsettings in Indiana.
(Described in detail in Appendix B.)
Hydrogeologic conditions within Indiana are extremely
varied. The SMP monitoring subcommittee has concluded that random
sampling should be conducted within the aquifers of eight principal
categories of hydrogeologic settings:
- Unconsolidated sediment underlying till plains.
- Moraine environments.
- Outwash fans.
- Outwash plains and valleys.
- Bedrock containing a thin cover of glacial drift.
- Tunnel valleys immediately beyond moraine-belts.
- Karst areas.
- Pennsylvanian bedrock of the driftless area.
The aquifers within each hydrogeologic setting are
considered to be separate entities with hydrologic and chemical
attributes that cannot be extrapolated beyond their physical boundaries.
Some aquifers, however, are comprised of significant subentities
that should be treated separately. For example, aquifers in outwash
fans and morainal areas are extremely heterogeneous, so that monitoring
wells within each significant subentity should be treated as independent
samples representing different statistical populations.
Within each hydrogeologic setting, all of the monitoring
wells will be in row crop areas, so that varying land use does
not strongly influence the data.
Location and frequency of water well sampling
Random samples of 10 to 15 monitoring wells will
be selected from each monitoring subunit. Information regarding
each well that will be entered into the GIS database will include:
(1) well identification numbers (s), (2) location - Universal
Transverse Mercator (UTM) coordinates, and (3) a subunit identification
code. Existing wells that meet the criteria of the SMP monitoring
subcommittee can be used only if they do not exhibit strong spatial
clustering (which may result in biased estimates of statistical
parameter values). Clustering of wells will be evaluated using
Nearest Neighbor Analysis. If a spatially random sample cannot
be achieved using existing wells, then new wells will need to
be installed at the closest accessible points to randomly selected
UTM coordinates.
From the initial samples, the exact number of sample
points in each monitoring subunit will be determined using the
method described above, any additional well locations will be
determined by random sampling. The need for new sampling subunits
will be addressed during this phase, as the preliminary data will
provide a basis for identifying significant subpopulations within
the data. It is also possible that one or more of the a priori
groupings can be eliminated on the basis of the preliminary statistical
analysis.
Water sampling
Water samples will be collected in a consistent manner.
Sampling activities will be conducted according to written Standard
Operating Procedures (SOP's). Written SOP's have been developed
for the following:
- Selection and Decontamination of Sampling Equipment
- Well Purging
- Sample Preservation
- Sample Transport
- Sample Custody
Water Sample Analysis
All sample analysis will be conducted under laboratory
conditions which meet or exceed EPA Quality Assurance Quality
Control criteria.
The following pesticide active ingredients will receive
highest priority for inclusion in a baseline monitoring network:
- 2,4-D
- alachlor
- atrazine
- carbofuran
- cyanazine
- metolachlor
- metribuzin
- simazine
- terbufos
Response Monitoring
Monitoring activities in response to a detection
of pesticide in ground water will be coordinated between IDEM
OWM Ground Water Section and the OISC. The activities include:
Data and source evaluation - confirmation of the
detection;
Perform vulnerability assessment and definition of
the response area;
Expand monitoring if necessary.
Evaluation Monitoring
Evaluation monitoring will provide follow-up monitoring
of known problem areas where BMP's or other restrictions have
been implemented to assess the success of the corrective measures.
The scope and design of an evaluation monitoring network will
be determined by the response monitoring area.
Standardization of Data
A standardized data collection format for water well
records has been developed by IDNR, Division of Water with input
from the Indiana Ground Water Task Force Resource Characterization
Work Group.
The format includes a unique identification number
to enable cross reference of each state agencies database while
enabling each state division to develop and use its own internal
ID numbering system. The key identification numbers have been
established as follows:
External ID # List
| 01 Indiana Department of Natural Resources
| |
| Division | 01 Water
|
| | 02 Geological Survey
|
| | 03 Reclamation
|
| | 04 Oil and Gas
|
| | 05 Soil Conservation
|
| 02 Indiana Department of Environmental Management
| |
| Division | 10-19 Office of Water Management
|
| | 20-29 Office of Solid and Hazardous Waste
|
| | 30-39 Office of Environmental Response
|
| | 40-49 Office of Air Management
|
| 03 Office of Indiana State Chemist
| |
| 04 Department of Health
| |
Example:
| FIELD NAMES
| EXTERNAL ID #
| INTERNAL ID #
| WATER WELL RECORD #
|
| Records
| 0101 |
xxxxxxxx |
(unique number)
|
In this example, the record would have been developed
by the Indiana Department of Natural Resources, Division of Water.
The next 8 digits would be their internal coding system for their
database.
In addition to utilizing the unique identification
numbering system for water well records developed by IDNR, IDEM
OWM Ground Water Section will utilize a data entry and information
management system for ground water data on pesticides (IC 13-7-26-3)
which conforms to the federal information processing standards
for all water well quality information. The 21 data elements are
listed below.
| 1 | Data Sources
|
| 2 | Latitude
|
| 3 | Longitude
|
| 4 | Method used to determine Latitude and Longitude
|
| 5 | Description of Entity
|
| 6 | Accuracy of Latitude and
Longitude measurement
|
| 7 | Altitude
|
| 8 | Method Used to determine Altitude
|
| 9 | State Federal Information Processing Standard (FIPS) Code
|
| 10 | County FIPS Code
|
| 11 | Well Identifier
|
| 12 | Well Use
|
| 13 | Type of Log
|
| 14 | Depth of Well at completion
|
| 15 | Screened/Open Interval
|
| 16 | Sample identifier
|
| 17 | Depth of Water
|
| 18 | Constituent or Parameter Measured
|
| 19 | Concentration/Value
|
| 20 | Analytical Results Qualifier
|
| 21 | Quality Assurance Indicator
|
