KITS
United Stales
Environmental Protection
Agency
Office of Water
Office of Pesticides and
Toxic Substances
Fall 1990
vvEPA National Pesticide Survey
Glossary
Active
Ingredient
Analyte
Analyte Stability
Study
Analytical
Method
Carcinogen
Community
Water System
(CWS)
Confidence
Interval
Contaminant
Contamination
The U.S. Environmental Protection Agency (EPA) has completed its five-year
National Survey of Pesticides in Drinking Water Wells (NPS). A joint project of EPA's
Office of Drinking Water (ODW) and Office of Pesticide Programs (OPP), the Survey
was designed to assess the extent and severity of the presence of pesticides and
nitrate in drinking water wells nationwide, and the relationship of pesticide use and
ground-water vulnerability to the presence of pesticides and nitrate. This glossary
defines terms relating to the Survey design, implementation, and results. The
definitions apply specifically to the Survey and may have additional meanings when
used in other circumstances.
The specific chemical in a product that is biologically active against pest organisms.
One of 127 chemicals that the Survey analytical methods were chosen or designed to
identify. The Survey analytes include 101 pesticides, 25 pesticide degradates, and
nitrate. Analytes were selected on the basis of expected leaching potential,
occurrence in ground water, volume of use, and other considerations.
An analysis of a laboratory sample in which a known quantity of an analyte has been
placed (a "spiked" sample). The sample is analyzed at a pre-determined time to
assess the stability and recovery of the analyte.
One of the eight chemical testing methods used to analyze Survey water samples. Six
of the analytic methods were specifically developed for the NPS.
A substance that is either known or suspected to cause cancer.
A system of piped drinking water that either has at least 15 connections or serves at
least 25 permanent residents. To be eligible for the NPS, a system had to have at
least one operable well (at the time of sampling) supplying drinking water.
The upper and lower limits around an estimated value within which the actual
population value is expected to fail. The confidence interval is stated as a specified
level, such as 95%, of confidence. For the NPS, estimates for wells throughout the
United States, based on analysis of results for the NPS sample of wells, are given with
a 95% confidence interval, indicating the upper and lower limits that EPA is reasonably
confident contain the actual detection rate.
Any substance such as a chemical, ion, radionuclide, synthetic organic compound,
microorganism, waste, or other substance that occurs in water causing it to be impure.
Contaminated water does not necessarily pose a health risk if the concentration of the
contaminant does not exceed acceptable drinking water standards.
The direct or indirect introduction of any contaminant into ground water caused in
whole or in part by human activities.
NPS Glossary
Printed on Recycled Paper
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Contract
Laboratory
Cropped and
Vulnerable
Degradate
Domains of
Interest
DRASTIC
Drinking Water
Well
EPA Laboratory
Estimated
Detection Limit
Federal
Insecticide,
Fungicide, and
Rodenticlde Act
(FIFRA)
Federal
Reporting Data
System
(FRDS)
Ground Water
One of the five laboratories hired to analyze Survey water samples. The laboratories
performed different analytic methods. EPA laboratories performed referee and
confirmation analyses to verify the results of the contract laboratories.
Sub-county areas specified for the rural domestic well survey that have high ground-
water vulnerability and greater than 25 percent of the land area used for agricultural
production or medium ground-water vulnerability and greater than 50 percent of the
land area used for agricultural production.
The product of the chemical or biological breakdown of a complex compound into
simpler compounds. See Pesticide Degradate.
The seven subgroups of the entire population of drinking water wells about which the
Survey was particularly interested in obtaining data. The seven domains of interest
are (1) community water systems nationally; (2) community water systems in counties
with the highest average ground-water vulnerability; (3) rural domestic wells nationally;
(4) rural domestic wells in counties with the highest average pesticide use;
(5) rural domestic wells in counties with the highest average ground-water
vulnerability; (6) rural domestic wells in counties with the highest average pesticide
use and ground-water vulnerability; and (7) rural domestic wells in "cropped and
vulnerable" areas of counties.
A classification system that attempts to provide a relative ranking of the vulnerability of
ground-water to contamination. The letters in DRASTIC stand for features of the area
around the well that may affect the movement of pesticides into ground water: (depth
to water, recharge, aquifer media, soil media, topography, impact of the unsaturated
aqueous zone between the soil media and water table, and conductivity of the
aquifer). DRASTIC does not consider sources of the contamination or population
affected. A DRASTIC score was computed for all of the counties in the United States
as part of the Survey.
A rural domestic well or a community water system well whose water is used primarily
for human consumption (i.e., drinking, cooking, and bathing).
One of two EPA laboratories that were chosen to manage contracts for the analytical
laboratories, and perform referee analyses.
The minimum concentration of an analyte that can be measured and reported with
confidence that the analyte concentration is greater than zero.
Federal law first enacted in 1947 and administered by the EPA since 1970. Under
FIFRA, EPA registers pesticide products and ensures that they will not present
unreasonable risks to human health or the environment when used according to label
directions.
A data base maintained by EPA's Office of Drinking Water (ODW) that contains
information on all public water supply systems in the United States. The FRDS was
used as the sampling frame for selecting community water system wells for NPS water
sampling and analysis.
Water found beneath the earth's surface contained in the interconnected pores and
fractures of soils and geologic formations.
NPS Glossary
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Ground-Water
Vulnerability
Health Advisory
Health Advisory
Level (HAL)
Health Advisory
Summary
Herbicide
Human Health
Risk
Hydrology
Insecticide
Leaching
Maximum
Contaminant
Level (MCL)
The degree to which ground water in the area surrounding a well is sensitive to
pesticide infiltration, based on an assessment of the hydrogeological makeup of an
aquifer, such as depth of the water table, soil properties, and ground-water recharge
rates.
A technical and scientific guidance document prepared by EPA for many of the
analytes included in the Survey. Each Advisory contains information on the analyte's
physicochemical properties, uses, chemical fate, health effects, treatment, and existing
criteria and guidelines. EPA also prepared non-technical Health Advisory Summaries
based on the Health Advisories.
The maximum concentration of a contaminant in water that may safely be consumed
over a specific time period. EPA sets HALs for short-term exposures, such as one day
and ten days, and longer-term exposures of greater than ten days up to several years,
and over a lifetime. A pesticide's HAL is based on health effects (other than cancer)
that were found in humans or in animals given high doses of the pesticide in
laboratory studies. For pesticides believed to cause cancer, EPA does not calculate a
Lifetime HAL Instead, EPA calculates the increased risks of cancer that are
associated with different concentrations and exposures to the pesticide.
A one-page summary prepared by EPA for many of the analytes included in the
Survey. These summaries provide concise information on possible health effects of
these chemicals and actions that may be taken to ensure a safe drinking water supply.
EPA distributed these summaries to the owners, residents, and operators of sampled
Survey wells in which analytes were detected.
A pesticide used to limit or inhibit plant growth.
The probability that a given exposure or series of exposures will damage the health of
individuals experiencing the exposures.
The science dealing with the properties, distribution, and circulation of water on the
land surface, in the soil, and in underlying rock formations.
A pesticide used to control insects.
The downward transport through the soil by percolating water of dissolved or
suspended minerals, fertilizers, pesticides, and other substances. A chemical's
solubility, the soil texture, and the amount and timing of water applied to the soil (as in
irrigation, rainfall, or heavy runoff) all contribute to the rate of leaching.
The maximum permissible level of a contaminant in water that is delivered to any user
of a public water system (established by the Safe Drinking Water Act (SDWA)).
Method Blank A portion of reagent water analyzed as if it were a sample.
Micrograms per
Liter (fig/L)
Milligrams per
Liter (mg/L)
One-millionth of a gram of a substance per liter of water, commonly referred to as
parts per billion. This unit of measurement was used for pesticides and pesticide
degradates in water samples during the Survey.
One-thousandth of a gram of a substance per liter of water, commonly referred to as
parts per million. This unit of measurement was used for nitrate in water samples
during the Survey.
WPS Glossary
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Minimum
Quantification
Limit (MQL)
Minimum
Reporting Limit
(MRL)
National
Pesticide
Survey Pilot
Study
National
Pesticide
Telecommuni-
cations Network
Nitrate (NO31
Nitrite (NCV)
Office of
Drinking Water
(ODW)
Office of
Pesticide
Programs (OPP)
Organic
Compound
Parts per billion
(PPB)
Parts per million
(PPM)
Pesticide
Pesticide
Degradate
The lowest concentration of an analyte in a sample that could be reliably measured
and reported as a detection with a measured concentration.
The lowest concentration of an analyte that could reliably be reported as a detection
of that analyte, established as one-half the MQL Analytes detected at a concentration
between one-half the MQL and the MQL were reported as detected, without a
measured concentration.
The preliminary study for the NPS conducted in 1987 in the States of California,
Minnesota, and Mississippi. The pilot study determined whether any changes in the
proposed Survey design were necessary or advisable prior to the implementation of
the full-scale Survey. The pilot program sampled approximately 50 rural domestic and
community water system wells.
A toll-free information service that answers inquiries on the health effects of pesticides
and pesticide poisonings. This service operates 24 hours a day and can be reached
at 1-800-858-7378.
An oxidized form of nitrogen that is an important plant nutrient and inorganic fertilizer.
The major sources of nitrate are septic systems, animal feed lots, agricultural fertilizers,
manured fields, industrial waste waters, sanitary landfills, and garbage dumps. Nitrate
also occurs naturally in ground water. The Survey analyzed water samples for the
combined presence of nitrate and nitrite, measured as nitrogen (N).
A form of nitrogen that is less oxidized than nitrate. Nitrite is a relatively unstable
transitional form between nitrate and ammonium.
The EPA office, under the management of the Office of Water, that is primarily
responsible for implementing the Safe Drinking Water Act (SDWA). The Office of
Drinking Water jointly conducted the NFS with the Office of Pesticide Programs.
The EPA office, under the management of the Office of Pesticides and Toxic
Substances, that is primarily responsible for implementing the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA). The Office of Pesticide Programs jointly
conducted the NFS with the Office of Drinking Water.
Natural or synthetic chemical containing carbon.
A measure that corresponds to one part pesticide in one billion parts of water.
PPB =
Weight of material
X 1,000,000,000
Total wt. of gas, liquid, or solid
A measure that corresponds to one part nitrate in one million parts of water.
PPM = Weight of material X 1,000,000
Total wt. of gas, liquid, or solid
Chemical substance used to destroy, control, or repel undesirable organisms which
may include plants, insects, fungi, nematodes, rodents, predators, or microorganisms.
A generic term that includes breakdown products of a pesticide active ingredient
resulting from biological processes (i.e., metabolites) and chemical processes (i.e.,
hydrolysis, photolysis, photooxidation). See Degradate.
WPS Glossary
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Pesticide
Metabolite
Public Water
Supply
Identification
Number
(PWSID)
Quality
Assurance (QA)
Quality Control
(QC)
Random Sample
Rapid Reporting
Level
Raw Water
Sample
Reagent Water
Relational
Analysis
Ruraj Domestic
Well
Safe Drinking
Water Act
(SDWA)
Safe Drinking
Water Hotline
Sample Blank
A product of biological processes (e.g., metabolism, or the chemical changes in living
cells) of a pesticide active ingredient by microorganisms, plants, or animals.
The unique identifying number given to public water systems in the Federal Reporting
Data System (FRDS) that was used when statistically selecting community water
systems for the NFS.
Oversight activities performed by EPA and its contractors to maintain quality control
standards and to ensure compliance with the standard operating procedures for
conducting well sampling, laboratory analysis, and processing Survey questionnaires.
Monitoring activities performed by EPA and its contractors to ensure that sampling,
data collection, and laboratory procedures are properly conducted and meet specified
performance standards.
A method of statistical sampling that ensures each member of the population has the
same chance of being chosen.
A level of pesticide or nitrate presence detected by the Survey laboratories that
warranted immediate contact with the well owner/operator. Rapid reporting occurred if
the measured detection equalled or exceeded EPA's Lifetime Health Advisory Levels
for the detected analyte.
A water sample gathered prior to treatment of any kind.
Water used in the laboratory quality assurance/quality control procedures that is
treated to remove any contaminant so it will not be observed at or above the
estimated detection limit of any analyte.
Any of the various types of statistical methods used to estimate the correlation or
relationship between variables in a given population.
A drinking water well that supplies an occupied private household located in rural
areas of the United States, except for wells located on government reservations. The
Census Bureau defines rural areas as households outside of incorporated or
unincorporated places with a population of 2,500 or more and outside of urban areas.
To be eligible for the Survey, the NPS required that the well be used for human
consumption (i.e., drinking, cooking, bathing).
A law passed in 1974 and administered by EPA that establishes national standards for
drinking water to provide a safe and wholesome water supply from both surface and
ground-water sources.
A toll-free hotline established by EPA in July 1987 to handle requests for information
on drinking water issues, including the NPS. The hotline can be reached at
1-800-426-4791 (in Washington, D.C. at (202) 382-5533) and is operated Monday
through Friday, 8:30 to 4:30 eastern standard time.
Water samples that were shipped to analytical laboratories for analysis and compared
to the analytical results of NPS well water samples to ensure that the analytical
methods were accurate.
NPS Glossary
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Scientific
Advisory Panel
(SAP)
Septic System
Spiked Sample
Surface Water
Synthetic
Organic
Compound
(SOC)
Temporal
Variability
Volatile Organic
Compound
(VOC)
Water Table
Well Casing
A panel of scientists created under the authority of FIFRA to advise the EPA on
scientific issues related to the assessment of risks posed by pesticides. A special
subpanel-of the SAP reviewed the NPS Survey design in 1985 and in 1987 reviewed
technical issues such as data collection options, well selection methods, temporal
variation, and analyte instability.
A sewage system composed of both a septic tank and septic field. The septic tank is
an underground watertight container made of durable material through which sewage
flows very slowly and in which solids separate from the liquid to be decomposed or
broken down by bacterial action. The septic field is the area through which the
sewage liquid passes and in which it is cleaned through physical filtering by soils,
biodegradation, and evaporation.
A water sample to which a known quantity of a pesticide has been added so that the
accuracy of the laboratory analyses can be determined.
Water found on the land surface in streams, ponds, marshes, lakes, or other fresh
water sources.
Man-made organic compound, not naturally found in ground water.
Seasonal fluctuations in weather conditions and pesticide use that may affect the
presence of pesticides in ground water and may potentially bias Survey sampling.
This problem was minimized by randomly allocating selected wells to specified two-
week periods within each strata across the two year sampling period.
An organic compound that evaporates (volatilizes) readily into the atmosphere and is
highly mobile in ground water.
The top of an unconfined (unpressurized) aquifer, below which the void spaces
resulting from the granular texture or fractures of earthen material are saturated with
water.
Materials such as concrete, piping, metal, and stone that line and support a well and
prevent it from collapsing.
WPS Glossary
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Where to Go
lor More
Information
This fact sheet is part of a series of NPS outreach materials, fact sheets and
reports. The following additional fact sheets are available through EPA's Public
Information Center (401 M Street SW, Washington DC 20460, 202-382-2080):
Survey Design
Survey Analytes
Quality Assurance/
Quality Control
Analytical Methods
Fact Sheet for each
detected anatyte
Project Summary
Summary Results
How EPA Will Use
The NPS Results
Additional information on the Survey and on pesticides in general can be
obtained from the following sources:
U.S. EPA Safe Drinking Water Hotline
1-800-426-4791 (In Washington, DC - 382-5533)
Monday-Friday, 8:30 am to 4:30 pm Eastern Time
National Pesticide Telecommunications Network
1-800-858-7378
24 hours a day
U.S. EPA Office of Pesticide Programs (OPP) Docket
401 M Street, SW Room NEG004
Washington, DC 20460
(202) 382-3587
National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161
(703) 487-4650
Information on regulation of
pesticides in drinking
water
Information on health
effects and safe
handling of pesticides
Background documents
for Survey (available
for review)
Copies of the
NPS Phase I Report
(available 1991) and
NPS Phase II Report
(when available)
If you are concerned about the presence of pesticides and nitrate in your private water
well, contact your local or State health department. Other experts in your State
environmental agency or agriculture and health department may also be helpful to
you. If you receive your drinking water from a community water system and have
questions about your water quality, contact your local community water system
owner/operator or the State water supply agency.
WPS Glossary
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