Nutrients, Select Pesticides, and Suspended Sediment in the 

Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06 

Scientific Investigations Report 2010–5167

Prepared in cooperation with the Kentucky Energy and Environment Cabinet

U.S. Department of the Interior

U.S. Geological Survey
Cover: Photograph of the headwater of Sinking Creek, Breckinridge County, Kentucky, 

March 4, 2004. Photograph by Angela S. Crain, U.S. Geological Survey.
Nutrients, Select Pesticides, and 

Suspended Sediment in the 

Karst Terrane of the Sinking Creek 

Basin, Kentucky, 2004–06

By Angela S. Crain

Prepared in cooperation with the Kentucky Energy and Environment Cabinet

Scientific Investigations Report 2010–5167

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Crain, A.S., 2010, Nutrients, select pesticides, and suspended sediment in the karst terrane of the Sinking Creek 

Basin, Kentucky, 2004–06: U.S. Geological Survey Scientific Investigations Report 2010-5167, 48 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................2

Purpose and Scope ..............................................................................................................................2

Description of Study Area ...................................................................................................................2

Stratigraphy ..................................................................................................................................2

Karst and Groundwater Hydrology ...........................................................................................4

Surface-Water Hydrology ..........................................................................................................4

Precipitation..................................................................................................................................5

Land Use and Land Cover...........................................................................................................6

Pesticide Use, Properties, Application, and Sales.................................................................7

Study Design and Methods..........................................................................................................................8

Sample-Station Selection and Sampling Frequency ......................................................................8

Sampling Methods................................................................................................................................8

Analytical Methods...............................................................................................................................9

Quality Control.....................................................................................................................................10

Statistical Analysis of Nutrients, Pesticides, and Suspended Sediment..................................11

Estimate of Daily Streamflow at the Sinking Creek at Rosetta Station......................................11

Load-Estimation Method ...................................................................................................................12

Sources of Nutrients ...................................................................................................................................13

Nonpoint-Source Contributions .......................................................................................................13

Atmospheric Deposition ...........................................................................................................13

Commercial Fertilizer and Livestock Waste..........................................................................14

Nitrogen Fixation by Soybeans................................................................................................15

Point-Source Contributions...............................................................................................................15

Concentrations, and Estimated Loads and Yields of Nutrients............................................................16

Concentrations of Nutrients..............................................................................................................16

Spatial Variability of Nutrients.................................................................................................16

Seasonal Variability of Nutrients.............................................................................................18

Estimated Loads and Yields of Nutrients ........................................................................................20

Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of 

Select Pesticides............................................................................................................................24

Occurrence and Distribution of Select Pesticides........................................................................24

Concentrations of Pesticides Compared to Drinking-Water Standards and 

Aquatic-Life Benchmarks ....................................................................................................26

Spatial Variability of Select Pesticides ..................................................................................27

Seasonal Variability of Select Pesticides ..............................................................................27

Estimated Loads and Yields of Select Pesticides..........................................................................30

Concentrations and Estimated Loads and Yields of Suspended Sediment........................................34

Concentrations of Suspended Sediment ........................................................................................34

Spatial Variability of Suspended Sediment ...........................................................................34

Hydrologic Variability of Suspended Sediment ....................................................................35

Estimated Loads and Yields of Suspended Sediment...................................................................35
iv

Contents—Continued

Summary and Conclusions.........................................................................................................................36

Acknowledgments.......................................................................................................................................37

References Cited..........................................................................................................................................37

Appendix 1. Station Name, Sample-Collection Date, Nutrient, and Suspended Sediment

Results for Samples Collected in the Karst Terrane of the Sinking Creek Basin, 

Kentucky, 2004–06 ..........................................................................................................................41

Appendix 2. Station Name, Sample-Collection Date, and Select Pesticide Results for 

Samples Collected in the Karst Terrane of the Sinking Creek Basin, Kentucky, 

2004–06.............................................................................................................................................45

Figures

Figure 1. Map showing location of the surface-water- and groundwater-sampling

stations in the karst terrane of the Sinking Creek Basin, Kentucky, study area ... 3

Figure 2. Map showing surficial geology in the karst terrane of the Sinking Creek Basin, 

Kentucky, study area........................................................................ 3

Figure 3. Map showing generalized distribution of sinkholes in the karst terrane of 

the Sinking Creek Basin, Kentucky, study area .......................................... 5

Figure 4. Graphs and maps showing precipitation and daily and estimated daily mean 

streamflow at selected surface-water stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, study area ............................................. 6

Figure 5. Map showing land cover in the karst terrane of the Sinking Creek Basin, 

Kentucky, study area........................................................................ 7

Figure 6. Graph showing correlation of same-day instantaneous streamflow between

the Sinking Creek at Rosetta station and the Sinking Creek near Lodiburg

station with mean annual streamflow and estimated peak-streamflow, 

low-streamflow, and harmonic-mean streamflow as supporting data ............... 11

Figure 7. Graphs showing concentrations of nitrite plus nitrate, total phosphorus, and 

orthophosphate at seven sampling stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, 2004–06 ................................................ 17

Figure 8. Graphs showing monthly distribution of nitrite plus nitrate, total phosphorus, 

and orthophosphate at seven sampling stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, 2004–06 ................................................ 18

Figure 9. Graphs showing seasonal variability of nitrite plus nitrate, total phosphorus, 

and orthophosphate at the Sinking Creek at Rosetta and the Sinking Creek 

near Lodiburg stations in the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004–06 ........................................................................... 19

Figure 10. Graphs showing relation between estimated and measured loads of nitrite 

plus nitrate, total phosphorus, and orthophosphate at two Sinking Creek 

mainstem stations in the karst terrane of the Sinking Creek Basin, Kentucky, 

2004–06 ....................................................................................... 23

Figure 11. Graph showing occurrence of pesticide compounds from all samples at all 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, study area, 

2004–06 ....................................................................................... 26
v

Figures—Continued

Figure 12. Boxplots showing concentrations of acetochlor, atrazine, deethylatrazine, 

metolachlor, and simazine at all sampling stations in the karst terrane of the

Sinking Creek Basin, Kentucky, 2004–06 ................................................ 28

Figure 13. Graphs showing monthly distribution of select pesticides at seven sampling 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06......... 29

Figure 14. Graphs showing seasonal variability of atrazine and its transformation 

product, deethylatrazine, at the Sinking Creek at Rosetta and the Sinking 

Creek near Lodiburg stations in the karst terrane of the Sinking Creek 

Basin, Kentucky, 2004–06 .................................................................. 30

Figure 15. Graphs showing relation between estimated and measured loads of select 

pesticides at two Sinking Creek mainstem stations in the karst terrane of 

the Sinking Creek Basin, Kentucky, 2004–06 ............................................. 33

Figure 16. Boxplots showing concentrations of suspended sediment at all sampling 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06......... 34

Figure 17. Boxplots showing seasonal distribution of suspended sediment concentrations

at seven sampling stations in the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004–06 ........................................................................... 35

Figure 18. Graphs showing relation between estimated and measured loads of suspended 

sediment at two Sinking Creek mainstem stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, 2004–06 ................................................ 36

Tables

Table 1. Surface-water and groundwater stations sampled in the karst terrane of 

the Sinking Creek Basin, Kentucky, 2004–06 ............................................. 4

Table 2. Mean land area of soybeans harvested and corn harvested for grain statewide, 

and in Breckinridge, Hardin, and Meade Counties, Kentucky, 2004–06............... 7

Table 3. Pesticide active-ingredient sales from Breckinridge, Hardin, and Meade 

Counties, Kentucky, 2004–06 ............................................................... 8

Table 4. Long-term method detection levels, laboratory reporting levels, and 

method reporting levels for nutrients and select pesticides established 

by the U.S. Geological Survey National Water-Quality Laboratory, 2004–06 ......... 9

Table 5. Summary of replicate sample data for commonly detected pesticides and 

pesticide-transformation compounds, nutrients, and suspended sediment ......... 10

Table 6. Estimated mean annual loads of total nitrogen and total phosphorus from 

nonpoint and point sources in the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004–06 ........................................................................... 13

Table 7. Summary statistics of the nutrients and suspended sediment in samples 

collected in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06 ...... 16

Table 8. Estimated mean annual load and yield of nutrients and suspended sediment 

at two Sinking Creek mainstem sites in the karst terrane of the Sinking Creek 

Basin, Kentucky, 2004–06 .................................................................. 21

Table 9. Regression coefficients and coefficients for determination (R2) for load 

models used to estimate loads of nitrite plus nitrate, total phosphorus, 

orthophosphate, and suspended sediment at two stations in the karst 

terrane of the Sinking Creek Basin, Kentucky, 2004–06................................. 22
vi

Tables—Continued

Conversion Factors and Abbreviations

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

mile (mi) 1.609 kilometer (km)

millimeter (mm) 0.03937 inch (in.)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

gallon (gal) 0.003785 cubic meter (m3) 

gallon (gal) 3.785 cubic decimeter (dm3) 

million gallons (Mgal) 3,785 cubic meter (m3)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

gallon per day (gal/d) 0.003785 cubic meter per day (m3/d)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

Mass

pound, avoirdupois (lb) 0.4536 kilogram (kg) 

Application and fixation 

pounds per acre (lb/acre) 1.121 kilograms per hectare (kg/ha)

pounds per square mile per year 

[lb/mi2)/yr]

1.7513 X 10-7 kilograms per square hectare per 

year [kg/ha2)/yr]

Table 10. Summary statistics of the detected herbicides and insecticides in samples 

collected at the sampling stations in the karst terrane of the Sinking Creek 

Basin, Kentucky, 2004–06; laboratory reporting levels, drinking-water standards, 

and aquatic-life criteria..................................................................... 25

Table 11. Pesticides and pesticide-transformation products analyzed in surface-water 

and groundwater samples from the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004–06 ........................................................................... 26

Table 12. Estimated mean annual load and yield of five select pesticides at two 

Sinking Creek mainstem stations in the karst terrane of the Sinking Creek 

Basin, Kentucky, 2004–06 .................................................................. 31

Table 13. Regression coefficients and coefficients for determination (R2) for load 

models used to estimate the loads of five select pesticides at two stations 

in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06. .................. 32
vii

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F = (1.8×°C)+32.

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

The measurement of the mesh size of sampling devices is measured in micrometers (μm); 

1,000 micrometers equals 1 millimeter (mm).

Abbreviations

AIC Akaike Information Criterion

AMLE Adjusted Maximum Likely Estimation

CIAT deethylatrazine

DEA deethylatrazine

DO dissolved oxygen

LAD Least Absolute Deviation

LRL Laboratory-reporting level

MCL maximum contaminant level

MDL method detection level

MOVE.1 Maintenance of Variance-Extension type 1

MRL method reporting level

NADP National Atmospheric Deposition Program

NASS National Agricultural Statistics Service

NPDES National Pollutant Discharge Elimination System

NWQL National Water Quality Laboratory

p probability

R2 coefficient of determination 

RPD relative percent difference

TMDL total maximum daily load

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

< less than

Conversion Factors and Abbreviations—Continued
viii

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Nutrients, Select Pesticides, and Suspended Sediment in the 

Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

By Angela S. Crain

Abstract

This report presents the results of a study by the U.S. 

Geological Survey, in cooperation with the Kentucky 

Department of Agriculture, on nutrients, select pesticides, and 

suspended sediment in the karst terrane of the Sinking Creek 

Basin. 

Streamflow, nutrient, select pesticide, and 

suspended‐sediment data were collected at seven sampling 

stations from 2004 through 2006. Concentrations of nitrite 

plus nitrate ranged from 0.21 to 4.9 milligrams per liter (mg/L) 

at the seven stations. The median concentration of nitrite plus 

nitrate for all stations sampled was 1.6 mg/L. Total phosphorus 

concentrations were greater than 0.1 mg/L, the U.S. 

Environmental Protection Agency’s recommended maximum 

concentration, in 45 percent of the samples. Concentrations 

of orthophosphates ranged from less than 0.006 to 0.46 mg/L. 

Concentrations of nutrients generally were larger during spring 

and summer months, corresponding to periods of increased 

fertilizer application on agricultural lands. Concentrations 

of suspended sediment ranged from 1.0 to 1,490 mg/L at the 

seven stations. Of the 47 pesticides analyzed, 14 were detected 

above the adjusted method reporting level of 0.01 micrograms 

per liter (μg/L). Although these pesticides were detected in 

water-quality samples, they generally were found at less than 

part-per-billion concentrations. Atrazine was the only pesticide 

detected at concentrations greater than U.S. Environmental 

Protection Agency drinking water standard of 3 μg/L, and the 

maximum detected concentration was 24.6 μg/L. 

Loads and yields of nutrients, selected pesticides, and 

suspended sediment were estimated at two mainstream 

stations on Sinking Creek, a headwater station (Sinking Creek 

at Rosetta) and a station at the basin outlet (Sinking Creek 

near Lodiburg). Mean daily streamflow data were available for 

the estimation of loads and yields from a stream gage at the 

basin outlet station; however, only periodic instantaneous flow 

measurements were available for the headwaters station; mean 

daily flows at the headwater station were, therefore, estimated 

using a mathematical record-extension technique known as 

the Maintenance of Variance-Extension, type 1 (MOVE.1). 

The estimation of mean daily streamflows introduced a large 

amount of uncertainty into the loads and yields estimates at 

the headwater station. 

Total estimated loads of select (five most commonly 

detected) pesticides from the Sinking Creek Basin were about 

0.01 to 1.2 percent of the estimated application, indicating 

pesticides possibly are retained within the watershed. Mean 

annual loads [(in/lb)/yr] for nutrients and suspended sediment 

were estimated at the two Sinking Creek mainstem sampling 

stations. The relation between estimated and measured 

instantaneous loads of nitrite plus nitrate at the Sinking Creek 

near Lodiburg station indicate a reasonably tight distribution 

over the range of loads. The model for loads of nitrite plus 

nitrate at the Sinking Creek at Rosetta station indicates small 

loads were overestimated and underestimated. Relations 

between estimated and measured loads of total phosphorus 

and orthophosphate at both Sinking Creek mainstem stations 

showed similar patterns to the loads of nitrite plus nitrate at 

each respective station. The estimated mean annual load of 

suspended sediment is about 14 times larger at the Sinking 

Creek near Lodiburg station than at the Sinking Creek near 

Rosetta station.

Estimated yields of nutrients and suspended sediment 

increased from the headwater to downstream monitoring 

stations on Sinking Creek. This finding suggests that 

sources of nutrients and suspended sediment are not evenly 

distributed throughout the karst terrane of the Sinking Creek 

Basin. Yields of select pesticides generally were similar 

from the headwater to downstream monitoring stations. 

However, the estimated yield of atrazine was about five times 

higher at the downstream station on Sinking Creek than at 

the headwater station on Sinking Creek. A predominantly 

cultivated agricultural land area of the karst drainage basin 

drains into Sinking Creek just downstream of the headwater 

station. Because the daily mean streamflow was estimated at 

the headwater monitoring station, the error in the estimated 

nutrient, select pesticide, and suspended-sediment loads 

and yields are subject to considerable and unknown biases 

and imprecision (greater standard error of predictions than 

reported). Additional streamflow and water-quality data are 

needed to improve the reliability of the load estimates and the 

errors associated with them at the upstream and downstream 

stations on Sinking Creek. 
2 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Introduction

Pesticides are chemical or biological substances that 

are used to control pests such as weeds (herbicides), insects 

(insecticides), and fungi (fungicides). Nearly 1 billion pounds 

of pesticides are used annually in the United States (Barbash 

and Resek, 1997). About 80 percent of pesticides are used 

for agricultural purposes, but pesticides also are used for 

industrial, commercial, and residential purposes. Pesticides 

are present in streams and aquatic ecosystems in many parts 

of the United States and the world (Larson and others, 1997). 

Many streams also contain nutrients, including nitrogen and 

phosphorus compounds, at concentrations exceeding natural 

conditions. Although pesticide and nutrient applications 

are useful for many purposes, excessive amounts of these 

compounds in the environment may cause a variety of adverse 

ecological or human-health effects. Suspended sediment plays 

a major role in the transport and fate of contaminants such as 

pesticides and nutrients, because contaminants may sorb onto 

the surface of suspended sediment particles and be transported 

and or deposited, or both, downstream. 

About 520 stream miles in Kentucky are considered 

to have impaired water quality because of nutrients, and 

about 420 stream miles are considered impaired because of 

suspended sediment (U.S. Environmental Protection Agency, 

2006a). Impaired water quality in Kentucky streams due to 

pesticides is unknown because of a lack of available data.

Water resources in the Sinking Creek Basin, in north 

central Kentucky, are particularly vulnerable to applications 

of pesticides and fertilizers because much of the basin is 

underlain by karst. Karst topography is characterized by 

internal or sinkhole drainage and rapid flow through solutional 

conduits, providing reduced attenuation of contaminants 

and enhanced potential for surface-water and groundwater 

contamination relative to nonkarst environments (Field, 

1990). Three streams in the Sinking Creek Basin have been 

listed in the State’s 2008 Integrated Report to Congress on 

the Condition of Water Resources in Kentucky as impaired 

by nutrients and suspended sediment (Kentucky Energy 

and Environment Cabinet, 2008a). These streams have been 

on the State’s 303(d) List of Impaired Waters since 2002 

(Kentucky Natural Resources and Environmental Cabinet, 

2003). Because of these impairments, Sinking Creek Basin has 

been designated a target priority watershed, and the State must 

develop plans to restore and maintain the water quality of the 

streams in the basin. The plans establish a “total maximum 

daily load,” or TMDL, for the impaired streams. A TMDL 

represents the total amount of contaminant that a water body 

can assimilate without violating the designated water-quality 

standard established by the U.S. Environmental Protection 

Agency.

In 2004, the U.S. Geological Survey (USGS), in 

cooperation with the Kentucky Department of Agriculture, 

began a study to determine concentrations and estimate loads 

and yields of nutrients, pesticides, and suspended sediment 

in the karst terrane of the Sinking Creek Basin. Information 

from this study will assist State and local water managers 

and planners, who are responsible for implementing TMDLs 

and who are responsible for drinking-water supplies in the 

Sinking Creek Basin, to make informed management decisions 

regarding acceptable levels of nutrients, pesticides, and 

suspended sediment.

Purpose and Scope

This report summarizes data collected at seven sampling 

stations from 2004 through 2006 to determine the presence 

and distribution of nutrients, select pesticides (5 of the most 

commonly detected of 47 analyzed), and suspended sediment 

in streams, springs, and karst windows in the Sinking Creek 

Basin in north-central Kentucky. Water samples were collected 

to make seasonal, spatial, and hydrologic evaluations of 

constituent concentrations, loads, and yields. Loads and yields 

of nutrients, select pesticides, and suspended sediment were 

estimated for two mainstem stations on Sinking Creek by use 

of S-LOADEST, a U.S. Geological Survey software program 

used to compute mean constituent loads in rivers by use of 

regression models. 

Description of Study Area

Stratigraphy

The Sinking Creek Basin (fig. 1) is mostly underlain by 

limestone formations of Mississippian through Pennsylvanian 

age (fig. 2). The limestone units of significance within the 

upper Sinking Creek Basin study area are the St. Louis 

Limestone and Ste. Genevieve Limestone. The St. Louis 

Limestone is mostly composed of sequences of massively 

bedded (tabular) limestones and shales, and the Ste. Genevieve 

Limestone is mostly composed of thin-bedded, cherty 

limestones. Overlying the Ste. Genevieve Limestone and 

St. Louis Limestone in parts of the Sinking Creek Basin, is a 

thick sequence of limestone, sandstone, and shale formations 

of Chester age (lower part). Rocks of lower Chester age 

are composed of alternating sandstone and limestone strata 

that include the Golconda Formation, which is sandstone 

dominated, and the Girkin Limestone (McDowell, 1986).
Introduction 3

Sinking Creek

0 5 10 MILES

0 6 12 KILOMETERS

Base from U.S. Geological Survey digital data, 2004, NAD83, Lambert Conformal Conic

EXPLANATION

Sinking Creek karst boundary

(Boiling Spring Basin)

Sinking Creek Basin

Irvington

Big Spring

Hardinsburg

86° 32' 86° 2'

38° 8'

37° 40'

MEADE COUNTY

BRECKINRIDGE COUNTY

HARDIN COUNTY

MEADE COUNTY

BRECKINRIDGE COUNTY

HARDIN COUNTY

Sinking Creek

near Lodiburg 03303205

Boiling Spring

F14CS002

Ross Karst Window

F14DS003

Sinking Creek at Rosetta

03303195

Flat Rock

Spring

F14DS005

Fiddle Spring

F14DS007

Big Spring

F15CS004

Ohio River

Figure 1. Location of the surface-water and groundwater-sampling stations in 

the karst terrane of the Sinking Creek Basin, Kentucky, study area.

Study area

Kentucky

Groundwater sampling station

Surface-water sampling station

Figure 1. Location of the surface-water- and 

groundwater-sampling stations in the karst 

terrane of the Sinking Creek Basin, Kentucky, 

study area.

EXPLANATION

Mississippian

Mgl - Ste. Genevieve, St. Louis limestone

Mcl - Lower Chesterian

Geology from McDowell, R.C., and others, 1981; Paylor, R.L., and others, 2003. 

# Surface-water sampling station

Groundwater sampling station

#

#

#

#

# #

0 5 10 MILES

0 5 10 KILOMETERS 86° 30’

37° 54’

37° 46’

86° 10’

86° 10’

86° 30’

37° 54’

37° 46’

Figure 2. Surficial geology in the karst terrane of the Sinking Creek Basin, Kentucky, study area.

Figure 2. Surficial geology in the karst terrane of the Sinking 

Creek Basin, Kentucky, study area.
4 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Karst and Groundwater Hydrology

The karst terrane portion of the Sinking Creek Basin, 

also known as the Boiling Spring Basin, encompasses about 

125 square miles (mi2) (fig. 1 and table 1). Groundwater is 

contributed to Sinking Creek by numerous karst features 

including sinkholes (fig. 3), caves, springs, and sinking 

streams. The exposure of Ste. Genevieve Limestone at the 

land surface allows water from surface-water streams to enter 

the underground cavities through sinkholes. Water also enters 

the Ste. Genevieve and Girkin Limestones through sinkholes 

developed in the sandstone members of the Golconda 

Formation.

Sinking Creek is one of the largest losing streams in 

Kentucky (Ray and others, 2005). Blue Fork and Stony Fork 

are two springs that form the headwaters of Sinking Creek 

in eastern Breckinridge County. Sinking Creek’s main losing 

reach is about 3 miles (mi) south of Irvington. A dry channel 

extends about 12 mi from the losing reach to Boiling Spring, 

where Sinking Creek once again flows on the surface to the 

Ohio River (George, 1976; Ray, 2001).

Because of its karst terrane, the Sinking Creek Basin 

is rated as hydrogeologically sensitive, indicating that 

contaminants in runoff are readily transported to and within 

a groundwater system (Ray and others, 1994).Water quality 

throughout the basin is directly affected by natural factors, 

such as geology, climate, and soils, and human factors, such as 

population and land use. 

Surface-Water Hydrology

Mean annual flow in Sinking Creek does not differ 

appreciably from year to year, but variations exist within each 

year based on precipitation conditions. A streamgaging station 

at Sinking Creek near Lodiburg, Ky. (USGS station 03303205) 

was installed and operated during the June 2004 through 

April 2007 study period; however, the time period from 

July 2006 through April 2007 was not included in this report. 

Mean annual streamflow at the Sinking Creek near Lodiburg 

station was 237 cubic feet per second (ft3/s) in 2005 and 

233 ft3/s in water year 2006 (fig. 4). Mean monthly streamflow 

from June through September of 2004 was 128 ft3/s. Mean 

streamflow was largest in the spring months, defined as 

March through May, and winter months, defined as December 

through February, and streamflow typically is lower during the 

summer and fall months of June through September. The mean 

daily streamflows for the Sinking Creek near Lodiburg station 

in water year 2004 ranged from 13 ft3/s on September 26–30 

to 4,140 ft3/s on May 31; mean daily streamflows in water 

year 2005 ranged from 9.3 ft3/s on July 21 to 3,910 ft3/s on 

March 28; mean daily streamflows in water year 2006 ranged 

from 9.1 ft3/s on November 25 to 5,440 ft3/s on May 26. 

The Kentucky Division of Water has measured Boiling 

Spring six times in 8 years during low- flow periods. Flow 

ranged from a low of 6.3 ft3/s during the 1999 drought to 

12.9 ft3/s. The mean low-flow discharge is 9.8 ft3/s (Ray 

and others, 2005). Peak flows at Boiling Spring have been 

estimated as 2,000 ft3/s (George, 1976).

Table 1. Surface-water and groundwater stations sampled in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.

[Percentage of basin area in indicated land use from Kentucky Land Cover Data Set, 2001, Kentucky Commonwealth Office of Technology. Abbreviations: 

USGS, U.S. Geological Survey; GW, groundwater; SW, surface water; KY, Kentucky; mi2, square mile. Symbols: –, data not available; <, less than]

USGS station No. USGS station name

(identifier on figure 1)

Type of 

station Latitude Longitude

Topographic 

drainage 

area

(mi2)

Percentage of basin area in indicated land use

Agriculture

Forest Urban Water

Cultivated Pasture

374755086090401 Big Spring - F15CS004 GW 37°47′55′′ 86°09′04′′ – – – – – –

374846086154101 Ross Karst Window - F14DS003 GW 37°48′46′′ 86°15′41′′ – – – – – –

374813086171501 Flat Rock Spring - F14DS005 GW 37°48′13′′ 86°17′15′′ – – – – – –

374847086172901 Fiddle Spring - F14DS007 GW 37°48′47′′ 86°17′29′′ – – – – – –

375209086224001 Boiling Spring - F14CS002 GW 37°52′09′′ 86°22′40′′ – – – – – –

03303195 Sinking Creek at Rosetta, KY SW 37°47′47′′ 86°16′25′′ 36 – – – – –

03303205 Sinking Creek near Lodiburg, KY SW 37°52′06′′ 86°23′16′′ 125 11 37 47 4 <1
Introduction 5

Geology from Paylor, R.L., and others, 2003.

EXPLANATION

Sinkholes

Sinking Creek Basin

Boiling Spring Basin

0 5 10 MILES

0 5 10 KILOMETERS 86° 30’

37° 54’

37° 46’

86° 10’

86° 10’

86° 30’

37° 54’

37° 46’

Figure 3. Figure 3. Generalized distribution of sinkholes in the karst terrane of the Sinking Creek Basin, Kentucky, study area Generalized distribution of sinkholes in the karst terrane of the Sinking Creek Basin, Kentucky, study area. .

Precipitation

Total precipitation for the upper Sinking Creek Basin at 

the streamflow station was 14.7 inches (in.) from June through 

September 2004, 42.6 in. in 2005, and 51.8 in. in 2006. Total 

precipitation at the nearest Cooperative (COOP) precipitation 

station (Hardinsburg, ID 153604) was 54.2 in. in 2004, 35.73 

in. in 2005, and 52.5 in. in 2006 (National Oceanic and 

Atmospheric Administration, 2008) (fig. 4). Precipitation 

during the growing season from April through October was 

32.6 in. or 60 percent of the total precipitation in 2004, 19.8 

in. or 55 percent of the total precipitation in 2005, and 33.5 in. 

or 64 percent of the total precipitation in 2006. The long-term 

mean annual precipitation for the period 1974–2000 for the 

Sinking Creek Basin is about 48 in.
6 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Land Use and Land Cover

Streams and springs in the karst terrane of the Sinking 

Creek Basin drain a diverse landscape of forest, agriculture, 

and developed areas, such as Irvington, Ky. About 48 

percent of the study area is agricultural land (fig. 5). Most 

of the agricultural land is used for pasture (37 percent); the 

remaining 11 percent of the agricultural land is used for corn, 

soybeans, wheat, hay, and tobacco production. Soybeans 

are the principal row crop harvested in the basin, followed 

by corn. Table 2 shows the mean land area of soybeans 

1

10

100

1,000

10,000

Sinking Creek at Rosetta

ESTIMATED DAILY MEAN STREAMFLOW,

IN CUBIC FEET PER SECOND

1

10

100

1,000

10,000

M J J A S O N D J F M A M J J A S O N D J F M A M J

2 0 0 4 2 0 0 5 2 0 0 6

Sinking Creek near Lodiburg

DAILY MEAN STREAMFLOW,

IN CUBIC FEET PER SECOND

J F M A M J J A S O N D 0

1

2

3

4

5

6

7

8

9

10

PRECIPITATION, IN INCHES

2004

2005

2006

86° 30’

37° 54’

37° 46’

86° 10’

86° 10’

86° 30’

37° 54’

37° 46’

0 5 10 MILES

0 5 10 KILOMETERS

Sinking Creek

#

#

Sinking Creek

near Lodiburg

03303205

Sinking Creek

at Rosetta

03303195

Sinking Creek

Sinking Creek

near Lodiburg

03303205

Sinking Creek

at Rosetta

# 03303195

#

Sinking Creek near Lodiburg

Figure 4. Precipitation and daily and estimated daily mean streamflow at selected surface-water stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, study area.

harvested and corn harvested for grain from 2004 to 2006 for 

Kentucky and for Breckinridge, Hardin, and Meade Counties 

in Kentucky (U.S. Department of Agriculture, 2008). Forested 

land comprises about 47 percent of the Sinking Creek Basin, 

and the most densely forested area is in the headwaters of the 

basin. Developed areas are about 4 percent of the land use in 

the basin. The most heavily populated community in the upper 

Sinking Creek Basin is Irvington, which has a population of 

about 1,450 people (U.S. Census Bureau, 2002).
Introduction 7

Pesticide Use, Properties, 

Application, and Sales

Herbicides commonly are used to 

control weeds in agricultural areas in the 

upper Sinking Creek Basin. The three classes 

of herbicides most commonly used in the 

upper Sinking Creek Basin are triazines, 

chloroacetanilides, and organophosphate 

herbicides, such as glyphosate. The most 

common triazine herbicides contain atrazine, 

simazine, and cyanazine and primarily 

are used on corn. The most common 

chloroacetanilide herbicides contain 

acetochlor and metolachlor and are used on 

both corn and soybeans. The most common 

organophosphate herbicide, glyphosate, is 

used on corn and soybeans. Combinations 

of herbicides applied to row crops are 

sometimes used for more effective weed 

control. Multiple applications are common 

and include some combination of preplanting 

applications of selective and nonselective 

herbicides and pre- and post-emergent 

applications of selective herbicides (Hippe 

and others, 1994). Both the triazine and 

chloroacetanilide groups have moderate to 

strong potential for transport, primarily in the 

dissolved phase, from fields through surface 

runoff (Goss, 1992). 

Chemical or biological processes 

can transform herbicides. Chemicaltransformation processes include 

photolysis or photochemical degradation, 

hydrolysis, oxidation, and reduction. The 

transformation of herbicides through 

microbial metabolic processes is considered 

the primary mechanism of biological 

degradation (Ritter and Shirmohammadi, 

Table 2. Mean land area of soybeans harvested and corn harvested for grain statewide, and in Breckinridge, 

Hardin, and Meade Counties, Kentucky, 2004–06.

[Data from U.S. Department of Agriculture, National Agricultural Statistics Service, 2008. Abbreviation: mi2, square mile]

State and County Land area 

(mi2)

Mean 

soybean 

harvest

(acres)

Mean land 

area of 

soybeans 

harvested 

(percent)

Mean 

harvested 

corn for grain 

(acres)

Mean land area 

of harvested 

corn for grain 

(percent)

Kentucky 39,732 1,303,000 5.1 1,120,000 4.4

Breckinridge 572 16,700 4.5 12,300 3.3

Hardin 308 27,300 14 23,870 12

Meade 628 15,200 3.8 10,170 2.5

Figure 5. Land cover in the karst terrane of the Sinking Creek Basin, 

Kentucky, study area.

Sinking Creek

Irvington

Big Spring

Hardinsburg

86° 32' 86° 2'

38° 8'

37° 40'

MEADE COUNTY

BRECKINRIDGE COUNTY

HARDIN COUNTY

MEADE COUNTY

BRECKINRIDGE COUNTY

HARDIN COUNTY

Sinking Creek

near Lodiburg

03303205

Boiling Spring F14CS002

Ross Karst Window

F14DS003

Sinking Creek at Rosetta

03303195 Flat Rock

Spring

F14DS005

Fiddle Spring F14DS007

Big Spring

F15CS004

Ohio River

Figure 5. Land cover in and around the karst terrane of the Sinking Creek 

Basin, Kentucky, study area.

EXPLANATION

Land cover

Urban

Forest

Agriculture

Pasture

Cultivated

Groundwater sampling station

Surface-water sampling station

Sinking Creek karst boundary

(Boiling Spring Basin)

Land cover from Kentucky Land Cover Data Set 2001, Kentucky Commonwealth Office of Technology, February 9, 2005.

Sinking Creek Basin

0 5 10 MILES

0 6 12 KILOMETERS
8 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

2001). Pesticide-transformation compounds are generally 

more water-soluble than their parent compounds. For 

example, Mills and Thurman (1994) found that one of the 

transformation compounds of the parent compound atrazine, 

deethylatrazine (DEA), sorbs less strongly to soils than does 

its parent compound. In some studies, pesticide-transformation 

compounds often have been detected at higher concentrations 

than their respective parent compound (Koplin and others, 

1998; Scribner and others, 1998). The toxicity of pesticidetransformation compounds is unknown (U.S. Geological 

Survey, 1999).

The amount of pesticides applied annually to agricultural 

land within the karst terrane of the Sinking Creek Basin, 

expressed in pounds of active ingredient, was derived from 

county-based crop-acreage data and State-level estimates of 

pesticide-use rates for individual crops from the National 

Agricultural Statistics Service (NASS) database (U.S. 

Department of Agriculture, 2008). County crop acreages were 

combined with the State pesticide-use coefficients to calculate 

county-level pesticide usage by pesticide and crop. The crops 

of interest included corn, soybeans, winter wheat, alfalfa hay, 

pasture, and tobacco. Little information was available for 

pesticide use in forestry; transportation, for weed control along 

roadways and right-of-ways; aquatic use for algae control; and 

various commercial and industrial applications.

Atrazine was the top-selling active ingredient of the 

pesticides studied in Breckinridge, Hardin, and Meade 

Counties in the Sinking Creek Basin. Other top-selling active 

ingredients within the counties that were studied included 

acetochlor, metolachlor, and simazine (table 3). Hardin, 

Breckinridge, and Meade Counties generally ranked within 

the top 30 of 98 counties reporting pounds of active ingredient 

for atrazine from 2004 to 2006. Hardin County consistently 

ranked higher for pounds of active ingredient for atrazine than 

Breckinridge and Meade Counties. It is assumed that higher 

sales equate to higher use of pesticides in the upper Sinking 

Creek Basin. 

Study Design and Methods

Sampling stations in the karst terrane of the Sinking 

Creek Basin were selected to assess the spatial and seasonal 

variability of nutrients, pesticides, and suspended sediment in 

areas of mixed land use and different types of agricultural land 

(fig. 5). Samples were collected at two Sinking Creek main 

stem stations, Sinking Creek at Rosetta, which has a 36-square 

mile drainage area, and Sinking Creek near Lodiburg, which 

has a 125-square mile drainage area; four springs, Big Spring, 

Flat Rock Spring, Fiddle Spring, and Boiling Spring; and one 

karst window, Ross Karst Window (fig. 1 and table 1). 

Sample-Station Selection and Sampling 

Frequency

Water-quality and suspended-sediment samples were 

collected from April 2004 through November 2004 and 

March 2005 through December 2005 at all sampling stations 

and from April 2006 through June 2006 at all stations except 

Boiling Spring and Ross Karst Window. To help minimize 

errors in the load estimates, samples were collected during 

high-flow events in addition to the scheduled monthly 

sampling. Four instantaneous streamflow measurements 

were made during high-flow conditions (substantial surface 

runoff) in addition to the other 18 instantaneous streamflow 

measurements made during monthly sampling. Water samples 

were not collected in the winter months so errors in the 

estimated loads are larger than reported by S-LOADEST. 

One hundred and thirty-one nutrient samples were collected 

and 155 suspended-sediment samples were collected at the 

stations. One hundred and twenty-nine samples were collected 

for pesticides and transformation compounds. Twenty-two 

samples composed of blanks, replicates, and pesticide spikes 

were collected for quality assurance/quality control. 

Sampling Methods

Representative water-quality and suspended-sediment 

samples from the Sinking Creek at Rosetta and Sinking 

Creek near Lodiburg stations were collected by means of the 

equal-width-increment method, in which depth-integrated 

samples were collected at equal distances across the entire 

stream width and composited (Edwards and Glysson, 1998). 

Dip samples were collected from the springs for waterquality and suspended-sediment analyses. An automatic 

suspended‐sediment pump sampler was installed at the 

downstream Sinking Creek near Lodiburg station (station 

number 03303205). All sampling material was constructed 

of Teflon® or fluorinated plastic to minimize contamination. 

Equipment used to collect and process nutrient and pesticide 

samples was precleaned with a 0.1-percent nonphosphate 

detergent, triple rinsed with tap water, rinsed with 5-percent 

hydrochloric acid for 30 minutes (nonmetal equipment only), 

Table 3. Pesticide active-ingredient sales from Breckinridge, 

Hardin, and Meade Counties, Kentucky, 2004–06.

[Amount of active ingredient from Ernest Collins, Kentucky Department of 

Agriculture, written commun., 2004, 2005, and 2006]

Pesticide active 

ingredient

Amount of active ingredient, in pounds

2004 2005 2006

Acetochlor 18,250 21,500 22,389

Atrazine 85,344 75,836 92,630

Metolachlor 20,777 21,230 24,564

Simazine 23,237 19,642 19,009
Study Design and Methods 9

triple rinsed with deionized water, rinsed with 

certified pesticide-free methanol, air dried, and stored 

in a dust-free environment prior to sample collection 

(Webb and others, 1999). 

Water samples for dissolved nutrients were 

filtered using a 0.45-micrometer (μm) average 

pore-size capsule filter that was prerinsed with 

deionized water and filtered native stream water and 

collected in the appropriate bottle types. Whole-water 

(unfiltered) nutrient samples were preserved using 

1 milliliter (mL) of 4.5N sulfuric acid. Samples for 

pesticides were pumped through Teflon® tubing and 

filtered through a 142-millimeter (mm) diameter, 

0.7-μm pore size, borosilicate glass-fiber filter placed 

in a stainless-steel filter unit (Sandstrom, 1995). The 

filtered water was collected in amber-colored glass 

bottles and chilled for later analysis of pesticides. 

Both the glass-fiber filters and the glass bottles 

had been baked at 450°C in a muffle furnace for 

a minimum of 2 hours. All nutrient and pesticide 

samples were chilled and shipped on ice to the USGS 

National Water Quality Laboratory (NWQL) in 

Lakewood, Colo., for analysis. Suspended-sediment 

samples were analyzed by the USGS Kentucky 

Water Science Center Sediment Laboratory in 

Louisville, Ky.

Field measurements of air temperature, 

barometric pressure, water temperature, specific 

conductance, pH, dissolved oxygen (DO), and 

turbidity were collected at the time of sampling 

(Wilde, chapter sections variously dated). Alkalinity 

and bicarbonate were determined by incremental 

tritration of a filtered water sample with 0.16N 

sulfuric acid using a digital titrator. Discharge was 

measured according to standard USGS guidelines as 

described by Rantz and others (1982).

A continuously recording water-quality monitor 

with a 15-minute-record interval was installed at 

the USGS streamflow-gaging station on Sinking 

Creek near Lodiburg (station number 03303205) 

on May 25, 2004, and removed on April 30, 2007. 

Water-quality properties measured with the monitor 

from May 2004 through April 2007 included water 

temperature, specific conductance, pH, and DO. 

Measurements were transmitted every 4 hours via 

satellite to the USGS Kentucky Water Science 

Center in Louisville, Ky., and were made available in 

near-real time on the World Wide Web at URL http//

ky.water.usgs.gov/. The water‐quality monitor was 

inspected on-site by USGS personnel approximately 

every 3 to 4 weeks to maintain calibration. 

Guidelines and standard operating procedures for 

maintaining the station and reporting the data are 

described in Wagner and others (2006). Data are 

currently available on the USGS public database 

NWISWeb online at: http://waterdata.usgs.gov/nwis.

Analytical Methods

The USGS NWQL analyzed the water-quality samples for the 

concentrations of nutrients and pesticides. Water‐quality samples for 

dissolved (filtered) and suspended (unfiltered) species of nitrogen and 

phosphorus were analyzed by colorimetric methods (Patton and Truitt, 

1992; Fishman, 1993; U.S. Environmental Protection Agency, 1993). 

These analyses quantified sample concentrations of dissolved nitrite 

plus nitrate, dissolved ammonia (ammonia plus ammonium), dissolved 

orthophosphate, and total phosphorus (table 4). Concentrations 

of nutrients discussed in this report represent their concentrations 

expressed as either nitrogen or phosphorus. For example, a 

concentration of nitrate expressed as 10 milligrams per liter (mg/L) 

refers to a concentration of nitrate of 10 mg/L as nitrogen.

Pesticide samples (laboratory schedule 2001) were analyzed 

using capillary-column gas chromatography/mass spectrometry with 

selected-ion sampling (Zaugg and others, 1995). Concentrations of 

47 pesticides were reported by the NWQL with appropriate qualifiers 

to indicate analytical limitations. Analytical data from the NWQL were 

reported as “less than” when a pesticide was not detected or not present 

at the method detection level (MDL). Table 4 presents the Long‐Term 

MDL of five select pesticides (those that were most commonly 

detected). The MDL is defined as the minimum concentration of 

a substance that can be identified, measured, and reported with 

99-percent confidence that the compound concentration is greater than 

zero (Wershaw and others, 1987). When the presence of a pesticide 

was detected and quantified in the sample and its reported value was 

less than the reporting level, the concentration was identified as an 

estimated value and footnoted.

Table 4. Long-term method detection levels, laboratory reporting levels, 

and method reporting levels for nutrients and select pesticides established 

by the U.S. Geological Survey National Water-Quality Laboratory, 2004–06.

[In some cases, more than one reporting level is given because these changed over the 

term of the project. Abbreviations: LT-MDL, Long Term-Method Detection Level; 

LRL, Laboratory Reporting Level; MRL, Method Reporting Level; N, nitrogen; 

P, phosphorus; mg/L, milligrams per liter; μg/L, micrograms per liter]

Constituent LT-MDL LRL/MRL

Nutrients

Ammonia (as N), dissolved 0.01 mg/L as N 0.04 mg/L as N

Nitrite plus nitrate (as N), dissolved 0.03 mg/L as N 0.06 mg/L as N

Phosphorus (as P), total 0.002 mg/L as P 0.004 mg/L as P

Orthophosphate (as P), dissolved 0.004 mg/L as P 0.006 mg/L as P

Select pesticides

Acetochlor 0.003 μg/L 0.006 μg/L

Atrazine 0.004 μg/L 0.007 μg/L

Deethylatrazine 0.003 μg/L 0.006 μg/L

Metolachlor 0.003/0.006 μg/L 0.0060/0.013 μg/L

Simazine 0.002 μg/L 0.005 μg/L
10 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

The USGS Kentucky Water Science Center analyzed 

the suspended-sediment samples by filtering samples through 

a 0.45-μm membrane filter. The filtrate was rinsed with 

deionized water to remove salts, and the insoluble material 

and filter were dried at 103°C and weighed (Fishman and 

Friedman, 1989). The laboratory reporting level for suspended 

sediment is 1 mg/L.

Quality Control

Quality-control information is needed to estimate 

potential bias and variability resulting from sample collection, 

sample processing, and laboratory analysis. About 16 percent 

of all samples submitted to the laboratory were quality-control 

samples, which included equipment blanks and field blanks 

to measure contamination and bias, and replicate samples to 

measure variability.

A blank is a water sample that consists of water that 

has undetectable concentrations of an analyte of interest. 

Blank-water samples are used to test for bias that could result 

from contamination during any stage of sample collection 

or the analysis process. Field-blank samples were collected 

to demonstrate that: (1) equipment has been adequately 

1 2 / ( 1 2) / 2*100,

where

1 is equal to the concentration in the

environmenal sample, in milligrams per liter

for nutrients or micrograms per liter for

pesticides; and

S2 is equal to the concentration i

RPD S S S S

S

= − +

n the replicate

 sample, in milligrams per liter for nutrients or

micrograms per liter for pesticides.

(1)

A large RPD can indicate greater variability in those 

samples. Median concentration differences, as measured by 

RPD, within replicate sets ranged from 1.7 to 8.2 percent for 

pesticides, 0 to 3.5 percent for nutrients, and were 5.3 percent 

for suspended sediment (table 5). The high maximum relative 

percent differences for some of constituents are likely because 

both detections in the replicate sample pair were near the 

reporting level for those constituents. The quality-assurance 

data indicate that adequate quality-control measures were used 

in the collection of the synoptic water-quality and sediment 

samples.

Table 5. Summary of replicate sample data for commonly detected pesticides and 

pesticide-transformation compounds, nutrients, and suspended sediment.

[The standard deviation is estimated from pairs of duplicate samples where the concentrations were 

above the reporting limit. The formula for the estimated standard deviation is from Taylor (1987). 

Abbreviation: RPD, relative percent difference]

Constituent

Number of 

replicate 

sample sets

Median 

RPD

Maximum

RPD

Estimated 

Standard 

Deviation

Pesticides

Acetochlor 7 2.9 40 0.0020

Atrazine 7 1.9 5.9 0.0166

Deethylatrazine1 7 8.2 18 0.0140

Metolachlor 7 1.7 17 0.0013

Simazine 7 4.6 13 0.0077

Nutrients

Ammonia (as N), 

dissolved

7 0.0 77 0.0353

Nitrite plus nitrate (as N), 

dissolved

7 0.4 6.5 0.0251

Phosphorus (as P), total 7 3.5 21 0.0287

Orthophosphate (as P), 

dissolved

7 2.2 35 0.0045

Sediment

Suspended sediment 5 5.3 95 6.058

1

Pesticide-transformation compound.

cleaned to remove contamination introduced 

by samples obtained at previous stations; 

(2) sample collection and processing have 

not resulted in contamination; and (3) sample 

handling, transport, and laboratory analysis 

have not introduced contamination (Mueller 

and others, 1997). The procedure for blank 

samples was to place pesticide-free water, 

which is a high grade of blank water that also 

is free of inorganic contaminants, through 

all sampling and filtration steps as a typical 

water-quality sample. Field-blank sample 

concentrations for pesticides or nutrients did 

not indicate any bias from contamination of 

the equipment or sample processing methods.

Replicate samples are a set of two or 

more environmental samples considered to 

be essentially identical in composition. All 

replicate samples were collected concurrently 

by use of one sampler and alternating the 

collection of samples into two or more 

compositing containers. Samples were then 

processed and analyzed independently. Data 

obtained from the seven sets of replicate 

samples was used to assess the variability of 

the overall sampling and analytical process. 

Replicate samples were compared by use of 

relative percent differences. Relative percent 

difference (RPD) for each analyte and 

replicate sample pair was calculated by the 

equation:
Study Design and Methods 11

Statistical Analysis of Nutrients, Pesticides, and 

Suspended Sediment

The S-Plus software program (Insightful Corporation, 

2005) was used to calculate summary statistics such as the 

mean, median, minimum, and maximum concentrations for 

nutrients, select pesticides, and suspended sediment. The 

Kruskall-Wallis nonparametric statistical test (Helsel and 

Hirsch, 2002) was used to make comparisons in the ranks of 

concentrations of nutrients, select pesticides, and suspended 

sediment among the groups of data. This tests for differences 

in the median ranks of two or more groups. If the KruskalWallis test on the entire group showed significant differences 

among groups, the Wilcoxon rank-sum test was performed 

on the ranked data to determine the statistical significance 

of differences in concentrations between groups of data. 

Differences between the groups of data with a probability (p) 

value of 0.05 or less were considered significant in this study.

Estimate of Daily Streamflow at the Sinking 

Creek at Rosetta Station

A mathematical record-extension technique known as 

the Maintenance of Variance-Extension, type 1 (MOVE.1) 

technique (Hirsch, 1982) was used to estimate streamflow 

for the partial-record station (Sinking Creek at Rosetta) 

by using same-day streamflows at the nearby gaging 

station (Sinking Creek near Lodiburg). Only instantaneous 

streamflow measurements were available at the partialrecord station. A total of 22 instantaneous streamflow 

measurements were made at the partial-record station over a 

range of flow conditions from April 2004 through November 

2004; March 2005 through December 2005; and April 2006 

through June 2006 (appendix 1). Of the 22 instantaneous 

streamflow measurements, 18 were made when the stream 

appeared to represent moderate-flow and low-flow conditions 

(no substantial surface runoff). The MOVE.1 method is 

one of three methods recommended for use by the USGS 

Office of Surface Water in Technical Memorandum No. 

86.02, Low‐Flow Frequency Estimation at Partial-Record 

Stations, issued December 16, 1985. The MOVE.1 technique 

assumes that a linear relation exists between the logarithms 

of the same-day streamflows at the partial-record station 

and a nearby streamgaging station. A graph of the relation 

between the logarithms of the same-day streamflows at the 

partial‐record station, Sinking Creek at Rosetta, and the 

nearby gaging station, Sinking Creek near Lodiburg, was 

linear (fig. 6), and the computed correlation coefficient of 0.95 

confirms that a linear relation exists between streamflow at the 

two stations. The means (Y and X ) and standard deviations 

(Sy and Sx) of the logarithms-base 10 of the same‐day flows 

for the partial-record and streamgaging stations and the 

logarithms-base 10 of the streamflow statistics ( Xi

 ) for 

the streamgaging station were calculated. Estimates of the 

streamflow statistics (Yi

 ) for the partial-record station were 

obtained by inserting the calculated values into the MOVE.1 

equation:

( ). Sy Yi Y Xi X

Sx

= + −   (2)

Estimates of streamflow for the partial-record station 

are transformed by exponentiating the estimates (Yi

 ) from 

logarithms back into their original units of measurement.

0.1 10 100 1,000 10,000 100,000

0.1

1

10

100

1,000

10,000

Correlation coefficient = 0.95

ESTIMATED STREAMFLOW, IN CUBIC FEET PER SECOND,

SINKING CREEK AT ROSETTA, KENTUCKY

STREAMFLOW, IN CUBIC FEET PER SECOND,

SINKING CREEK NEAR LODIBURG, KENTUCKY

2-year peak streamflow (Q2)

MOVE.1 line

Same-day instantaneous streamflow

Peak-streamflow estimate

Low-streamflow estimate

Estimated harmonic-mean streamflow

Mean annual streamflow

5-year peak streamflow (Q5)

7-day 2-year low streamflow (7Q10)

7-day 10-year low streamflow (7Q10)

Figure 6. Correlation of same-day instantaneous streamflow between the Sinking Creek

at Rosetta station and the Sinking Creek near Lodiburg station with mean annual streamflow

and estimated peak-streamflow, low-streamflow, and harmonic-mean streamflow as 

supporting data. [Q2, Q5, 7Q2, 7Q10, and mean annual streamflow from KYGEONET at http://kygeonet.ky.gov/kyhydro/main.htm

1

Figure 6. Correlation of same-day 

instantaneous streamflow between 

the Sinking Creek at Rosetta 

station and the Sinking Creek near 

Lodiburg station with mean annual 

streamflow and estimated peakstreamflow, low-streamflow, and 

harmonic-mean streamflow as 

supporting data.
12 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

various functions of streamflow and time. The S-LOADEST 

program is incorporated in the computer program S-Plus 

(Insightful Corporation, 2005). 

S-LOADEST estimates loads using three statistical 

estimation methods: Adjusted Maximum Likelihood 

Estimation (AMLE), Maximum Likelihood Estimation (MLE), 

and Least Absolute Deviation (LAD). The user chooses the 

most appropriate method for the data being analyzed. The 

AMLE method was selected for all models, because the input 

data in this study included censored data (concentrations 

below the reporting level), and the model calibration residuals 

were normally distributed within acceptable levels. 

The S-LOADEST software allows the user to choose 

between selecting the general form of the regression 

from several predefined models and letting the software 

automatically select the best-defined model, on the basis of 

the Akaike Information Criterion (AIC) (Akaike, 1981). The 

predefined model with the lowest value for the AIC is then 

selected for use in load estimation. S-LOADEST contains 

nine predefined rating-curve models that can test the relation 

between constituent load and streamflow. The seven-parameter 

regression model has been shown to work well with estimating 

nutrient loads (Cohn and others, 1992) and was selected for 

this study. The regression models for the select pesticides in 

this study did not include all of the terms below, depending on 

the specific model selected by the software. The “best” model 

indicated in S-LOADEST was different for each station and 

select pesticide; however, a consistent model for each select 

pesticide was chosen to estimate loads for both stations and 

periods in the basin. Use of the seven-parameter regression 

model was applicable to estimating pesticide annual loads in 

this study, because the dataset adequately represents periods 

when small to negligible concentrations of pesticides are 

normally found. However, an analysis of the “best” models 

compared to the general seven-parameter model (equation 3) 

indicated small improvement in reduction of variance. 

The output regression equations take the following 

general form:

( ) ( ) ( )

] [

2

2

ln ln ln

[sin(2 ) cos(2 )] ,

where

is the constituent load, in pounds per day;

is the stream discharge, in cubic feet per 

second;

is the time, in decimal years from the 

beginning of 

L a b Q c Q

d pT e pT fT gT

L

Q

T

= + +

+ + + +

the calibration period; and

a,b,c,d,e, f,g are regression coefficients.

(3)

Runkel and others (2004) provide a complete discussion 

of the theory and principles behind the calibration and 

estimation methods.

There is a large uncertainty in the estimated daily 

streamflows at the partial-record station, because (1) only 

instantaneous streamflow measurements were available 

at the partial-record station; (2) the drainage area at the 

partial‐record station is about 29 percent of the drainage 

area of the streamgaging station; and (3) the partial-record 

station is a headwater station indicating streamflow response 

to precipitation events is usually quicker than at downstream 

stations. Additional streamflow data were used to support the 

use of the MOVE.1 technique in extending the streamflow 

record at the partial-record station. The additional streamflow 

data used in support included estimates of low-streamflow, 

peak-streamflow, and mean annual streamflow from the 

KYGEONET geographic information system datasets, 

available online at http://kygeonet.ky.gov/kyhydro/main.

htm), and the harmonic-mean streamflows (Martin and Ruhl, 

1992) (fig. 6). The flow statistics from the KYGEONET, 

which are calculated using regression-based methods and 

basin characteristics (Ruhl and Martin, 1991; Martin, 2002; 

Hodgkins and Martin, 2003) are in good agreement with the 

line of correlation determined by the MOVE.1 method (fig. 6). 

The KYGEONET low-flow statistics include the annual 

minimum 7Q2 and 7Q10 low-flow values. These statistics 

are based on the minimum average 7-consecutive-day flow 

from each year of record with a recurrence interval of 2 years 

and 10 years. For example, a 7Q10 of 1.0 ft3/s means that the 

annual minimum average 7-consecutive-day streamflow of 

less than 1.0 ft3/s should be expected at the station, on average, 

once every ten years (Hayes, 1991). The KYGEONET peakflow statistics include the Q2 and Q5 peak‐flow values. These 

statistics refer to the peak discharges for recurrence intervals 

of 2 and 5 years. The KYGEONET mean annual streamflow 

is the arithmetic mean of the individual daily mean discharges 

for a designate period. This statistic lies within the set of data 

points on the MOVE.1 correlation line. The harmonic-mean 

streamflow statistic also lies within the set of data points on 

the MOVE.1 correlation line, and is determined by summing 

the inverses of daily mean streamflow data for the entire 

period of record and dividing the resulting sum by the number 

of data values. The quotient is reciprocated to yield the 

harmonic mean. 

Load-Estimation Method

Linear-regression models were developed by use of 

the USGS software S-LOADEST for the estimation of 

loads for the select pesticides atrazine, acetochlor, simazine, 

and metolachlor, and the transformation compound, 

deethylatrazine; loads for the nutrients nitrite plus nitrate, total 

phosphorus, and orthophosphate; and suspended sediment for 

the period 2004–2006. This S-LOADEST software is based 

on LOADEST (Runkel and others, 2004) and uses time-series 

streamflow data and constituent concentrations to calibrate a 

regression model that describes constituent loads in terms of 
Sources of Nutrients 13

The model calibration procedure performed by 

S-LOADEST uses instantaneous discharge data and 

concurrent instantaneous concentration data, provided by 

the user in a calibration file for each station. Data used in the 

calibration files for this study were collected from April 2004 

through November 2004, March 2005 through December 

2005, and April 2006 through June 2006. Samples were not 

collected in the winter months so errors in the estimated loads 

are larger than reported by S-LOADEST. The total number 

of concentration measurements in the calibration files for 

each station varied, depending on the constituent, but ranged 

from 20 samples for suspended sediment at each station to 

24 samples for nutrients and pesticides at each station.

Estimation files containing daily mean streamflow 

data, in cubic feet per second, were used in S-LOADEST to 

estimate annual and daily loads at the Sinking Creek at Rosetta 

station and the Sinking Creek near Lodiburg station from 

April 2004 through June 2006. The daily mean streamflow for 

the Sinking Creek at Rosetta station was estimated by use of 

the MOVE.1 technique. 

Sources of Nutrients

The sources of nutrients in the karst terrane of the 

Sinking Creek Basin are categorized as being from point 

or nonpoint sources (table 6). Contaminant sources that 

are diffuse and do not have a single point of origin into 

receiving streams are called nonpoint sources. Nonpoint 

sources of nutrients include atmospheric deposition, fertilizer 

applications from agricultural and residential areas, feed-lot 

discharges, septic systems, and urban runoff. Point sources 

differ from nonpoint sources in that they discharge directly 

into a receiving stream at a discrete or localized point. Point 

sources primarily consist of a variety of large and small 

wastewater-treatment facilities, as well as storm-water runoff 

and sewer overflows.

Nonpoint-Source Contributions

Nonpoint sources of nutrients estimated in this report 

for the karst terrane of the Sinking Creek Basin include 

atmospheric deposition, commercial fertilizer application, 

livestock waste, and nitrogen fixation from soybeans. Nutrient 

inputs from urban runoff, combined sewer overflows, and 

septic systems were not included in the nonpoint source 

estimates of this report because of minimal or no data. In 

addition, there is limited urban land use in the basin, so urban 

runoff and combined sewer overflows are not extensive and 

are possibly minimal nutrient input sources within the basin.

Atmospheric Deposition

Atmospheric deposition of nitrogen has been measured at 

a National Atmospheric Deposition Program (NADP) station 

(KY19) located at Seneca Park, in Jefferson County, since 

October 2003. The wet deposition data from NADP include 

nitrate, ammonia nitrogen, and other constituents. No dry 

deposition data are measured; therefore, total atmospheric 

deposition of nitrogen cannot be obtained. Atmospheric 

deposition of phosphorus is not measured by NADP because 

concentrations are generally not significant and samples are 

subject to contamination (National Atmospheric Deposition 

Program, 2008).

Rates of wet deposition of inorganic nitrogen in 2004, 

2005, and 2006 were 437,000 pounds per year (lb/yr) 

(3,500 pounds per square mile (lb/mi2), 350,000 lb/yr 

(2,800 lb/mi2), and 450,000 lb/yr (3,600 lb/mi2), respectively. 

The 3-year mean rate (2004–06) of wet deposition of inorganic 

nitrogen was 412,000 lb/yr (3,300 lb/mi2) (table 6). The 

NADP provides annual-summary reports that are available 

online at http://nadp.sws.uiuc.edu/.

Table 6. Estimated mean annual loads of total nitrogen and total 

phosphorus from nonpoint and point sources in the karst terrane 

of the Sinking Creek Basin, Kentucky, 2004–06.

[Abbreviations: NA, not applicable. Symbol: –, data not available]

Source

Mean annual load, in pounds per year

Total nitrogen Total phosphorus

Inputs to land

Atmospheric deposition1 412,000 NA

Farm fertilizer2 1,780,000 377,000

Nonfarm fertilizer2 22,600 4,560

Livestock waste3 328,000 96,300

Nitrogen fixation4 16,600 NA

Septic systems5 293,000–846,000 67,700–135,000

Input to streams

Municipal wastewater 

discharge6

1,500 –

1

Data from National Atmospheric Deposition Program, 2008. Dry 

deposition nitrogen not included in atmospheric deposition.

2

Ruddy and others, 2006. Data from 2001.

3

U.S. Department of Agriculture, 2004.

4

Kentucky Agricultural Statistics Service, 2004.

5

U.S. Census Bureau, 1990 and 2002; U.S. Environmental Protection 

Agency, 2002.

6

U.S. Environmental Protection Agency, 2006b.
14 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Commercial Fertilizer and Livestock Waste

Commercial fertilizers applied to agricultural lands have 

become a primary nonpoint source of nitrogen and phosphorus 

in the United States. Commercial nitrogen fertilizer is applied 

as either ammonia or nitrate and commercial phosphorus 

fertilizer is commonly applied as phosphate. Application 

of nitrogen and phosphorus in commercial fertilizers in 

the United States from 1945–93 has increased by 20 and 

3.6 percent, respectively (Ruddy and others, 2006).

County-level data for nitrogen and phosphorus inputs 

from farm and nonfarm applications of commercial fertilizer 

and from livestock waste were compiled in a national data set 

(Ruddy and others, 2006). The methods for allocating data 

on state total fertilizer sales to individual counties and for 

estimating livestock-waste inputs from livestock populations 

are described in detail by Ruddy and others (2006). The 

county-level data then were disaggregated by parsing the 

percentage of the basin within the counties and then summing 

the values. The use of county-level data has some limitations 

in its application, because fertilizer and livestock waste 

sources are not evenly distributed within counties and because 

typically smaller-sized farms do not have to report usage. The 

use of county-level data are generally more applicable to large 

drainage basins that encompass entire counties than smaller 

drainage basins that encompass only parts of one or more 

counties. 

Farm fertilizer inputs of nutrients in 2001 are estimated 

to have been 1,780,000 lb of nitrogen and 377,000 lb of 

phosphorus in the karst terrane of the Sinking Creek Basin, 

an average of about 14,200 (lb/mi2)/yr of nitrogen and about 

3,020 (lb/mi2)/yr of phosphorus applied (table 6). The amount 

of cultivated agricultural land in the karst terrane of the 

Sinking Creek Basin is about 12 percent, or about 15 mi2. 

Nitrogen and phosphorus fertilizers generally are applied to 

corn fields in spring, just before seeding. Livestock waste also 

can be applied to fields during this time. Nitrogen fertilizer is 

reapplied to corn fields 6–10 weeks after planting. Phosphorus 

fertilizer is applied to corn and soybeans at the time of 

planting. Nitrogen and phosphorus fertilizers and livestock 

waste are applied in late summer through early fall for 

cool‐season pasture, hay fields, and wheat fields (University of 

Kentucky, 2001).

Nonfarm fertilizer contributions of nutrients in 2001 are 

estimated to have been 22,600 lb of nitrogen and 4,560 lb 

of phosphorus in karst terrane of the Sinking Creek Basin 

(table 6). The estimated average annual application per square 

mile is about 181 (lb/mi2)/yr for nitrogen and 37 (lb/mi2)/yr 

for phosphorus. 

Nutrient-input estimates from livestock waste were based 

on county-level livestock-population data collected by the 

U.S. Census Bureau during the Census of Agriculture. The 

method and assumptions used in Ruddy and others (2006) to 

estimate nitrogen and phosphorus content of livestock waste 

produced by the various types of livestock are described by 

Goolsby and others (1999). The livestock groups used to 

estimate nutrient inputs from livestock waste include beef 

cattle, dairy cows, hogs, and poultry.

Nitrogen and phosphorus in livestock waste can be a 

major source of nitrogen and phosphorus loads in streams 

draining agricultural areas. Animal-feeding operations and 

concentrated animal-feeding operations, which concentrate 

animals, feed, and waste on a small land area, have greater 

potential to contribute nutrients to surface runoff and 

groundwater than other livestock operations. Wastes produced 

by these operations may be applied to pasture and crop 

land and are subsequently taken up by plants or lost to the 

environment. An animal-feeding operation in Kentucky is 

defined as a facility where animals are confined and fed for 

a total of 45 days or more in any 12-month period and where 

crops, vegetation forage growth, or postharvest residues are 

not sustained over any portion of the facility in the normal 

growing season (Kentucky Energy and Environment Cabinet, 

2008b). An animal-feeding operation is defined as a confined 

animal-feeding operation when more than 300 animal units are 

confined at the facility, and there are contaminants discharged 

into the waters of the Commonwealth, or more than 

1,000 head of beef cattle, 700 head of dairy cattle, 2,500 pigs, 

25,000 broilers, or 82,000 laying hens or pullets are present 

at the facility. There were six animal-feeding operations and 

no confined animal-feeding operations within the karst terrane 

of the Sinking Creek Basin as of July 2008 (James Seamy, 

Kentucky Energy and Environment Cabinet-Division of Water, 

written commun., 2008).

In Kentucky, the average inputs of nutrients from 

livestock waste were 1,100,000 lb of nitrogen and 320,000 lb 

of phosphorus in 1997. In Breckinridge, Hardin, and 

Meade Counties, mean nutrient inputs were 4,030,000 lb of 

nitrogen and 1,190,000 lb of phosphorus. Disaggregating 

the county-level data by parsing the percentage of the basin 

within the counties and then summing the values, the mean 

nutrient inputs were 328,000 lb of nitrogen and 96,300 lb of 

phosphorus for the karst terrane of the Sinking Creek Basin. 

These nutrient inputs average about 2,620 (lb/mi2)/yr of 

nitrogen and 770 (lb/mi2)/yr of phosphorus throughout the 

area. Actual nitrogen inputs to the land are probably lower 

because of volatilization of ammonia from the waste and 

nitrification and denitrification. The county-level data were 

disaggregated by parsing the percentage of the basin within 

the counties and then summing the values.
Sources of Nutrients 15

Nitrogen Fixation by Soybeans

Nitrogen fixation by soybeans is an important source 

of nitrogen in the karst terrane of the Sinking Creek Basin 

because of the acreage of soybeans in the study area. The 

amount of nitrogen produced by fixation from soybeans in the 

basin is based on the area of soybeans planted and an annual 

nitrogen fixation rate of 105 pounds per acre (lb/acre), as used 

by Hoos and others (1999) for soybeans in the Southeast. This 

rate was multiplied by the mean harvested acres for soybeans 

in 2004–06 in the basin (U.S. Department of Agriculture, 

2008) to estimate the amount of fixed nitrogen. The estimated 

nitrogen fixation for the karst terrane of the Sinking Creek 

Basin was 16,600 (lb/mi2)/yr (table 6).

Point-Source Contributions

The Irvington wastewater treatment facility is the only 

permitted municipal wastewater treatment facility in the karst 

terrane of the Sinking Creek Basin. This facility has a mean 

flow of 0.04 million gallons per day (Mgal/d) based on 2007 

and 2008 data.

Nutrient inputs from the wastewater facility are based 

on monthly average information from the National Pollutant 

Discharge Elimination System (NPDES) permitting program 

of the USEPA. The required sampling data for NPDES 

discharges are stored in the USEPA Permit Compliance 

System data base (U.S. Environmental Protection Agency, 

2008b). The Irvington wastewater-treatment facility monitors 

effluent for ammonia, but concentrations of total nitrogen 

and total phosphorus were not available. A regression 

equation, developed from more than 800 observations of 

effluent concentrations from municipal wastewater-treatment 

facilities in Virginia and North Carolina, was used to estimate 

concentrations of total nitrogen from concentrations of 

ammonia nitrogen (McMahon and Lloyd, 1995, p. 70–71). 

The regression equation is:

Total nitorgen = 11.97 + 0.55 (ammonia),

where concentrations are in milligrams per liter, as nitrogen.

Nitrogen inputs to streams from the municipal 

wastewater-treatment facility were estimated using 2007 and 

2008 data in the following equation:

( )( )( )( ),

where

is nutrient load in lb/yr;

is wastewater effluent flow in cubic feet per second;

is concentraton of nutrient, in milligrams per liter;

is a unit conversion factor of 5.3943; and

L RQ C f T

L

RQ

C

f

=

T is time in days per year.

(4)

Monthly load estimated for nitrogen were calculated by 

multiplying the average daily discharge for the month by the 

average nitrogen concentration. Monthly load estimates were 

summed over the year. The estimated input from wastewater 

discharge was 1,500 lb/yr for nitrogen (table 6). The error 

in this estimate is unknown, because it is based on a set 

of data outside the study area and because the variability 

around this relation is not shown in McMahon and Lloyd 

(1995). Estimated inputs from wastewater discharge for total 

phosphorus were not available.

The use of septic systems is common throughout the 

study area. In 1990, more than 22,000 septic systems were in 

use within Breckinridge, Hardin, and Meade Counties (U.S. 

Census Bureau, 1990). Septic systems are mostly used for 

individual households or small commercial establishments, 

such as churches, restaurants, convenience stores, that are 

located in rural areas or that are not served by a domestic 

wastewater facility. Water from septic systems generally is 

released to the ground through an absorption field after natural 

biological treatment. 

Based on an average discharge of 69 gallons per 

day (gal/d) per person (U.S. Environmental Protection 

Agency, 2002) and 2.47 people per household (U.S. Census 

Bureau, 2002), estimated water released from each septic 

tank is about 170 gal/d. Discharge from the nearly 22,000 

septic tanks in Breckinridge, Hardin, and Meade Counties 

is about 3.7 Mgal/d. The average concentration of total 

nitrogen and the average concentration of total phosphorus 

in typical residential wastewater range from 26 to 75 mg/L 

for total nitrogen and 6 to 12 mg/L for total phosphorus 

based on literature values (U.S. Environmental Protection 

Agency, 2002). Thus, an estimated mean annual load of total 

nitrogen of about 293,000 to 846,000 lb/yr, and an estimated 

mean annual load of total phosphorus of about 67,700 to 

135,000 lb/yr is discharged from septic tanks throughout 

Breckinridge, Hardin, and Meade Counties (table 6).
16 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Concentrations, and Estimated Loads 

and Yields of Nutrients

Summary statistics for the concentrations of ammonia, 

nitrite plus nitrate, total phosphorus, and orthophosphate 

were collected from April 2004 through November 2004, and 

March 2005 through December 2005 at all sampling stations 

(Sinking Creek at Rosetta; Sinking Creek near Lodiburg; 

Big Spring; Flat Rock Spring; Boiling Spring; Ross Karst 

Window; and Fiddle Spring), and April 2006 through June 

2006 at all stations except Boiling Spring and Ross Karst 

Window. Summary statistics for concentrations of nutrients 

and suspended sediment in samples from all selected stations 

are shown in table 7. The results of all the samples collected 

and analyzed are provided in appendix 1. These data provide 

the basis for analysis of concentrations at the selected 

sampling stations and the loads and yields at the Sinking 

Creek near Lodiburg and Sinking Creek at Rosetta stations.

Concentrations of Nutrients

Although nutrients such as nitrogen and phosphorus are 

necessary for plant and animal life, in excessive quantities 

they can accelerate the growth of aquatic plants and cause 

algal blooms. Excessive aquatic plant growth may result 

in unsuitable habitat conditions for aquatic animals and 

can interfere with recreational activities such as fishing, 

swimming, and boating. Decomposition of aquatic plant 

growth can cause odor and taste problems in drinking-water 

supplies and can consume dissolved oxygen, which can 

adversely affect aquatic life (Journey and Arrington, 2009).

Spatial Variability of Nutrients

Concentrations of nitrate greater than 10 mg/L in 

drinking water can have adverse human-health effects (Ward 

and others, 2005). Concentrations of nitrite plus nitrate ranged 

from 0.21 to 4.9 mg/L at the seven stations (fig. 7). The 

highest concentration of nitrite plus nitrate of 4.9 mg/L was 

observed at the Big Spring station. The lowest concentration 

of nitrite plus nitrate of 0.21 mg/L was observed at the Sinking 

Creek at Rosetta station. The median concentration of nitrite 

plus nitrate for all stations sampled was 1.6 mg/L. The Big 

Spring station had the highest median nitrite plus nitrate 

concentration, 2.3 mg/L. The range of median concentrations 

of nitrite plus nitrate was 0.85 mg/L at the Sinking Creek at 

Rosetta station to 1.8 mg/L at the Flat Rock Spring station.

The nonparametric statistical tests (Kruskal-Wallis 

and Wilcoxon rank-sum) were used to examine the nutrient 

concentrations for significant differences among the sampling 

stations. The Kruskal-Wallis test does not determine which 

medians of the nutrient concentrations at the stations 

are different, so the Wilcoxon rank-sum test was used to 

determine which stations had significantly different nutrients 

concentrations. Differences between the groups of data 

with a probability (p) value of 0.05 or less were considered 

significant. The number of samples collected at each station 

during 2004 through 2006 ranged from 12 to 23 samples. 

Significant differences (Kruskal-Wallis, p-value = <0.001) 

in concentrations of nitrite plus nitrate occurred among the 

sampling stations, with pair-wise comparisons (Wilcoxon 

rank-sum) showing that concentrations of nitrite plus nitrate 

at the downstream Sinking Creek near Lodiburg station were 

significantly larger than those at the headwater, Sinking Creek 

at Rosetta station, and at the Big Spring station. 

Table 7. Summary statistics of the nutrients and suspended sediment in samples collected in the karst terrane of the 

Sinking Creek Basin, Kentucky, 2004–06.

 [Abbreviations: mg/L, milligrams per liter; N, nitrogen; P, phosphorus; LD, less than laboratory reporting level; E, estimated]

Constituent Number of 

samples

Laboratory 

reporting level 

(mg/L)

Concentrations, in mg/L

Minimum Median Maximum

Ammonia, as N 131 0.04 LD LD 0.61

Nitrite plus nitrate, as N 131 0.06 0.21 1.6 4.9

Total phosphorus, as P 130 0.004 LD 0.08 0.89

Orthophosphate, as P 131 0.006 E0.003 0.043 0.46

Suspended sediment1 156 1 1 73 1,490

1

Includes automatic-sampler results. 
Concentrations, and Estimated Loads and Yields of Nutrients 17

Data outside

10th and 90th percentile

90 percent

75 percent

Median

25 percent

10 percent

EXPLANATION

(23) Number of samples collected

CONCENTRATION, IN MILLIGRAMS PER LITER CONCENTRATION, IN MILLIGRAMS PER LITER

0

1

2

3

4

5

6

Nitrite plus nitrate

Figure 7. Concentrations of nitrite plus nitrate, total phosphorus, and orthophospate at seven sampling stations in the karst terrane of the 

Sinking Creek Basin, Kentucky, 2004-2006.

0.0

0.2

0.4

0.6

0.8

1.0

(23)

SINKING

CREEK

AT ROSETTA

(19)

BIG SPRING

F15CS004

(14)

ROSS

KARST

WINDOW

F14DS004

(19)

FLAT ROCK

SPRING

F14DS005

(16)

FIDDLE

SPRING

F14DS007

(12)

BOILING

SPRING

F14CS002

(28)

SINKING

CREEK

NEAR

LODIBURG

(23)

SINKING

CREEK

AT ROSETTA

(19)

BIG SPRING

F15CS004

(14)

ROSS

KARST

WINDOW

F14DS004

(19)

FLAT ROCK

SPRING

F14DS005

(16)

FIDDLE

SPRING

F14DS007

(12)

BOILING

SPRING

F14CS002

(28)

SINKING

CREEK

NEAR

LODIBURG

Total phosphorus

Orthophosphate

USEPA recommended

criteria for total 

phosphorus

Figure 7. Concentrations of nitrite plus nitrate, total phosphorus, and orthophosphate at seven sampling stations in the 

karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
18 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Phosphorus is a common element in the rocks of 

the Sinking Creek Basin; other sources of phosphorus 

include sewage effluent, detergents, and leachates 

from septic tanks. No aquatic-life criterion exists for 

total phosphorus. However, the USEPA recommends a 

maximum total phosphorus concentration of 0.1 mg/L 

in streams that do not directly discharged into lakes and 

reservoirs to discourage excessive growth of aquatic 

plants and algae (U.S. Environmental Protection Agency, 

1986). Total phosphorus concentrations were greater 

than 0.1 mg/L in 45 percent of the samples (fig. 7). 

The median concentration of total phosphorus for all 

stations sampled was 0.09 mg/L. Concentrations of 

orthophosphates ranged from <0.006 to 0.46 mg/L. The 

highest concentration of orthophosphate, 0.46 mg/L, was 

measured at the Big Spring station (fig. 7). 

Significant differences (Kruskal-Wallis, p-value = 

0.003) in concentrations of total phosphorus occurred 

among the sampling stations, with pair-wise comparisons 

(Wilcoxon rank-sum) showing that concentrations 

of total phosphorus at the headwater, Sinking Creek 

at Rosetta station (0.03 mg/L), were statistically 

significantly smaller than those at the Flat Rock Spring 

station, the Ross Karst Window station, and the Sinking 

Creek near Lodiburg station. Results of the KrusalWallis test for concentrations of orthophosphate (p-value 

= <0.001) indicated significant differences among the 

stations. The Wilcoxon rank-sum test showed that 

concentrations of orthophosphate at the Sinking Creek at 

Rosetta station of 0.01 mg/L were significantly smaller 

than those at all other stations.

Seasonal Variability of Nutrients

Concentrations of nutrients can vary seasonally. 

Mean concentrations of nitrite plus nitrate measured 

tended to be higher in the late spring and early summer 

(June and early July) and early winter (late November 

and December) and lower in early spring (March) and 

autumn (September and October) in the karst terrane 

of the Sinking Creek Basin (fig. 8). An increase in 

precipitation in the early winter allows for the runoff of 

nutrients, such as nitrite plus nitrate, into the streams. 

In addition, increases in the concentrations of nitrite 

plus nitrate in early winter are possibly because of the 

release from biota as they become dormant or die off. 

Precipitation decreases in autumn, allowing plants to 

uptake much of the available nutrients in the soil; thus, 

concentrations of nitrite plus nitrate decrease in streams. 

Concentrations of nitrite plus nitrate, total phosphorus, 

and orthophosphate in relation to daily mean streamflow 

at the Sinking Creek near Lodiburg station and Sinking 

Creek at Rosetta station are shown in figure 9.

Concentrations of nitrite plus nitrate were slightly higher 

in late spring and early summer and lower in late summer and 

autumn at the Sinking Creek at Rosetta station. A possible 

cause of lower concentrations of nitrite plus nitrate in late 

summer and autumn is increased nutrient uptake resulting 

from longer days and warmer temperatures. Concentrations 

of nitrite plus nitrate remained constant throughout the 

sampling period at the Sinking Creek near Lodiburg station. 

Significant differences (Kruskal-Wallis, p-value = 0.001) 

in concentrations of nitrite plus nitrate occurred among the 

seasons, with pair-wise comparisons (Wilcoxon rank‐sum) 

indicating that concentrations of nitrite plus nitrate were 

statistically different between spring and summer. No 

statistical differences were indicated for the other season 

comparisons. 

(7)

(12)

(12)

(23)

(23)

(13)

(13) (14)

(14)

(7)

(7)

(7)

(7)

(8)

(21) (43)

(7)

(12)

(23) (13)

(14)

(7)

(7)

Figure 8. Monthly distribution of nitrite plus nitrate, total phosphorus,

and orthophosphate at seven sampling stations in the karst terrane of 

the Sinking Creek Basin, Kentucky, 2004-2006. MONTHLY MEAN CONCENTRATIONS, IN MILLIGRAMS PER LITER

Nitrite plus nitrate

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Total phosphorus

Orthophosphate

(8)

(8) (21)

(21)

(8) Number of samples (43)

(43)

(7)

(8) Number of samples

0.0

1.0

2.0

3.0

0.0

0.1

0.2

0.3

0.4

0.5

Figure 8. Monthly distribution of nitrite plus nitrate, total 

phosphorus, and orthophosphate at seven sampling stations 

in the karst terrane of the Sinking Creek Basin, Kentucky, 

2004–06.
Concentrations, and Estimated Loads and Yields of Nutrients 19 Figure 9. Seasonal variability of nitrite plus nitrate, total phosphorus, and orthophosphate at the Sinking Creek at Rosetta and the Sinking Creek near Lodiburg stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.

1010.10.01

Continuous streamflowTotal phosphorusOrthophosphate

1010.10.010.001

Estimated continuous streamflowTotal phosphorusOrthophosphate

1001010.1

Continuous streamflowNitrite plus nitrate

1

10

100

1,000

10,000 10

10.1

1

10

100

1,000

10,000

Estimated continuous streamflowNitrite plus nitrate

CONCENTRATION, IN MILLIGRAMS PER LITER

Figure 9. Seasonal variability of nitrite plus nitrate, total phosphorus, and orthophosphate at the Sinking Creek at Rosetta and the Sinking Creek near Lodiburg stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006.

ESTIMATED DAILY MEAN STREAMFLOW, DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND,

IN CUBIC FEET PER SECOND,

SINKING CREEK AT ROSETTA

SINKING CREEK NEAR LODIBURG

M J J A S O N D J F M A M J J A S O N D J F M A M J

2 0 0 4 2 0 0 5 2 0 0 6

M J J A S O N D J F M A M J J A S O N D J F M A M J

2 0 0 4 2 0 0 5 2 0 0 6
20 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Mean concentrations of total phosphorus and 

orthophosphate tended to be higher in the spring (March 

through May) and summer (June through August) and 

lower in the autumn (September to November) and early 

winter (December) (fig. 8). Samples were not collected in 

January and February. Concentrations of total phosphorus 

and orthophosphate were higher during periods of increased 

streamflow, mainly in the spring, and lower when streamflow 

decreased at the Sinking Creek at Rosetta station and the 

Sinking Creek near Lodiburg station (fig. 9). This could be 

because of the relation between phosphorus and sediment, 

which possibly is mobilized during high-flow events. The 

seasonal pattern for orthophosphate was similar to that 

of orthophosphate. The concentration of orthophosphate 

was slightly higher than total phosphorus in a March 2005 

sample at the Sinking Creek at Rosetta station; however, the 

difference was less than 0.01 mg/L and within the analytical 

variance of the methods. The Kruskal-Wallis test (p-value = 

0.008) performed on the concentrations of total phosphorus 

indicated significant differences among the seasons. Pair‐wise 

comparisons using the Wilcoxon rank-sum test showed 

concentrations of total phosphorus were statistically different 

between summer and autumn with higher concentrations of 

total phosphorus occurring in the summer.

Estimated Loads and Yields of Nutrients

Load represents the mass, usually expressed in pounds or 

tons, of a given water-borne constituent moving past a given 

point per unit of time. Annual loads can vary depending upon 

drainage basin size, hydrologic conditions, and land uses 

within a basin. Mean annual loads [(in/lb)/yr] for nutrients 

were estimated by use of the S-LOADEST program at the 

two Sinking Creek mainstem sampling stations from samples 

collected from 2004 through spring 2006 (table 8). The ratio of 

the standard error of prediction to the mean load standardizes 

the model error and provides a comparison among the load 

estimates at the two stations. The prediction error of the 

mean load of nitrite plus nitrate estimates was 17 percent at 

the Sinking Creek at Rosetta station, and 10 percent at the 

Sinking Creek near Lodiburg station (table 8). The prediction 

error of the mean load of total phosphorus and orthophosphate 

estimates at the Sinking Creek at Rosetta station were 59 and 

69 percent, respectively (table 8). The Sinking Creek near 

Lodiburg station had prediction errors of the mean of total 

phosphorus and orthophosphate estimates of 31 and 28 

percent, respectively (table 8). These values indicate that the 

regression models had low error in the estimates of nitrogen 

and more error in the estimates of phosphorus. Because the 

daily mean streamflow was estimated at the Sinking Creek 

at Rosetta station, the error in the estimated nutrient loads at 

this station is larger than that determined by the S-LOADEST 

model alone, because it includes considerable and unknown 

biases and imprecision in the streamflow estimates. Loads 

were not estimated at the springs or karst window station, 

because continuous streamflow data were not available.

The coefficients of determination (R2) for the bestfit regression models for loads of nitrite plus nitrate, total 

phosphorus, and orthophosphate are listed in table 9. High 

R2 values indicate that the models for all four constituents 

successfully simulated the variability in constituent loads 

at the two Sinking Creek mainstem stations. Measured 

instantaneous loads of nitrite plus nitrate, total phosphorus, 

and orthophosphate for the two Sinking Creek mainstem 

stations were plotted against estimated loads for the same 

day to visually assess the fitness of the model (fig. 10). Points 

above the 1:1 line indicate that the model underestimated the 

loads; points below the line indicate the model overestimated 

the loads. The relation between estimated and measured loads 

of nitrite plus nitrate at the Sinking Creek near Lodiburg 

station indicate a reasonably tight distribution near the 1:1 

line over the range of loads (fig. 10). The model for loads 

of nitrite plus nitrate at the Sinking Creek at Rosetta station 

indicates small loads were overestimated and underestimated 

(fig. 10). Relations between estimated and measured loads of 

total phosphorus and orthophosphate at both Sinking Creek 

mainstem stations showed similar patterns to the loads of 

nitrite plus nitrate at each respective station (fig. 10). 

The estimated mean annual loads of nitrite plus nitrate 

at the Sinking Creek at Rosetta station and the Sinking 

Creek near Lodiburg station were 92,900 and 665,000 lb/yr, 

respectively (table 8). The mean annual total load of nitrogen 

from the estimate reported by Michael C. Ierardi and others 

(U.S. Geological Survey, unpub. data, 2006) is similar to the 

estimate for mean annual load of nitrite plus nitrate in this 

report. The estimates reported by Michael C. Ierardi and others 

(U.S. Geological Survey, unpub. data, 2006) are provided by a 

U.S. Geological Survey internal interactive tool SPARROWWEB display. Access is provided to reach-level information 

through a user-navigated hierarchical system of mapped 

watersheds, based on the Water Resources Council hydrologic 

drainage basin classification for the United States. This nested 

drainage basin classification includes 18 water‐resources 

regions, 204 sub-regions, 334 accounting units, and 

2,106 hydrologic cataloging units (i.e., 8-digit HUCs). 

Selection of a river reach displays water-resource statistics 

for the drainage basin above the reach, including drainage 

area, mean-annual stream discharge and water velocity, land 

use, and population, as well as predictions of mean-annual 

nutrient (total nitrogen and total phosphorus ) concentrations 

and yields and nutrient sources from the SPARROW 

(SPAtially Referenced Regressions on Watershed attributes) 

watershed model. The model predictions also include natural 

background concentrations and yields of nutrients for the 

river reach (Smith and others, 2003). Estimated mean annual 

load for total nitrogen was 809,000 lb/yr as reported by 
Concentrations, and Estimated Loads and Yields of Nutrients 21

Michael C. Ierardi and others (U.S. Geological Survey, unpub. 

data, 2006). Although Michael C. Ierardi and others (U.S. 

Geological Survey, unpub. data, 2006) reported mean annual 

loads for total nitrogen but not nitrite plus nitrate, the major 

form of nitrogen in the karst terrane of the Sinking Creek 

Basin is nitrite plus nitrate, which is about 84 percent of total 

nitrogen. This estimate is based on water-quality samples 

collected by the Kentucky Division of Water mainly under 

wading conditions. Load estimates from stations that have 

long periods of record are more reliable than estimates from 

stations that have short periods of record.

The Sinking Creek at Rosetta station contributed an 

estimated mean annual load of total phosphorus of 

17,100 lb/yr during 2004 to 2006, which is about 10 percent 

of the total estimated mean annual load at the Sinking Creek 

near Lodiburg station, from about 29 percent of the overall 

drainage area. The estimated mean annual load of total 

phosphorus of 63,900 lb/yr, reported by Michael C. Ierardi 

and others (U.S. Geological Survey, unpub. data, 2006), 

is much lower than the estimate for mean annual load of 

total phosphorus in this report for the Sinking Creek near 

Lodiburg station of 177,000 lb/yr. There is about a 94 percent 

relative difference between the estimated total phosphorus 

load in this report and the estimate reported by Michael 

C. Ierardi and others. As previously stated, the estimates 

reported by Michael C. Ierardi and others (U.S. Geological 

Survey, unpub. data, 2006) are provided by a U.S. Geological 

Survey internal interactive tool SPARROW-WEB display. 

Access is provided to reach-level information through a 

user-navigated hierarchical system of mapped watersheds, 

based on the Water Resources Council hydrologic drainage 

basin classification for the United States. This nested drainage 

basin classification includes 18 water‐resources regions, 

204 sub-regions, 334 accounting units, and 2,106 hydrologic 

cataloging units (i.e., 8-digit HUCs). Selection of a river 

reach displays water-resource statistics for the drainage basin 

above the reach, including drainage area, mean-annual stream 

discharge and water velocity, land use, and population, as well 

as predictions of mean-annual nutrient (total nitrogen and total 

phosphorus) concentrations and yields and nutrient sources 

from the SPARROW (SPAtially Referenced Regressions on 

Watershed attributes) watershed model. The model predictions 

also include natural background concentrations and yields of 

nutrients for the river reach (Smith and others, 2003).

Table 8. Estimated mean annual load and yield of nutrients and suspended sediment at two Sinking Creek mainstem sites in the karst 

terrane of the Sinking Creek Basin, Kentucky, 2004–06.

[Abbreviations: N, nitrogen; P, phosphorus; lb/yr, pound per year; (lb/yr)/mi2, pound per year per square mile; DA, drainage area; mi2, square mile. 

Symbol: –, not available]

Constituent

Estimated mean 

annual load

(lb/yr)

Standard

error of 

prediction

Prediction 

error

(percent)

Estimated mean 

annual yield 

[(lb/yr)/mi2]

Estimated mean annual 

load and yield from Ierardi 

and others (U.S. Geological 

Survey, unpub. data, 2006)

Load

(lb/yr)

Yield

[(lb/yr)/mi2]

Sinking Creek at Rosetta, Ky.

(DA = 36 mi2)

Ammonia (as N), dissolved – – – – – –

Nitrite plus nitrate (as N), dissolved 92,900 15,800 17 2,580 – –

Phosphorus (as P), total 17,100 10,100 59 475 – –

Orthophosphate (as P), dissolved 6,700 4,600 69 187 – –

Suspended sediment 10,300,000 6,360,000 62 280,000 – –

Sinking Creek near Lodiburg, Ky.

(DA = 125 mi2)

Ammonia (as N), dissolved – – – – –

Nitrite plus nitrate (as N), dissolved 665,000 65,900 10 5,300 809,000 4,600

Phosphorus (as P), total 177,000 54,000 31 1,400 63,900 370

Orthophosphate (as P), dissolved 37,400 10,400 28 300 – –

Suspended sediment 143,000,000 61,600,000 43 1,140,000 – –
22 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

The estimated mean annual loads for orthophosphate for 

the Sinking Creek at Rosetta station and the Sinking Creek 

near Lodiburg station are 6,700 and 37,400 lb/yr, respectively 

(table 8). The mean annual load of orthophosphate represented 

a larger percentage, 33 percent, of the mean annual load of 

total phosphorus at the Sinking Creek at Rosetta station than 

at the Sinking Creek near Lodiburg station, where it was 

21 percent. A possible reason for the larger percentage of 

orthophosphate to total phosphorus at the Sinking Creek at 

Rosetta station may be nutrients contributed by a hog farm 

located upstream of the sampling station.

Yields are defined as the amount of load per unit area 

and are useful for comparing basins with varying size, land 

use, and physiography. Yields for nitrite plus nitrate, total 

phosphorus, and orthophosphate were computed for each of 

the three fixed-sampling stations (table 8).

Estimated historical mean-annual yields (Michael C. 

Ierardi and others, U.S. Geological Survey, unpub. data, 2006) 

of nitrite plus nitrate and total phosphorus for the Sinking 

Creek near Lodiburg station were somewhat similar to those 

computed from samples collected in 2004–06. Estimated 

mean annual yields of total nitrogen and total phosphorus 

from Michael C. Ierardi and others (U.S. Geological 

Survey, unpub. data, 2006) were 4,700 and 370 (lb/yr)/mi2, 

respectively; whereas, the mean annual yield of nitrite plus 

nitrate was 5,300 (lb/yr)/mi2 and the mean annual yield for 

total phosphorus was 1,400 (lb/yr)/mi2 for the years 2004 to 

2006 at the Sinking Creek near Lodiburg station. Mean annual 

streamflow for the Sinking Creek near Lodiburg station was 

245 ft3/s for water years 2004 to 2006, compared to 259 ft3/s 

for the 1970–92 period reported by Michael C. Ierardi and 

others (U.S. Geological Survey, unpub.data, 2006).

Table 9. Regression coefficients and coefficients for determination (R2) for load models used to estimate loads of nitrite plus nitrate, 

total phosphorus, orthophosphate, and suspended sediment at two stations in the karst terrane of the Sinking Creek Basin, Kentucky, 

2004–06.

[The regression equation is ln(L)=a + b(lnQ) + c(lnQ2) + d[sin(2πT)] + e[cos(2πT)]+ fT +gT2: where L is the constituent load, in pounds per day; Q is stream 

discharge, in cubic feet per second; T is time in decimal years from the beginning of the calibration period; a, b ,c, d, e, f, g are regression coefficients; R2

represents the amount of variance explained by the model. Estimated residual variance is the maximum likelihood estimation variance corrected for the number 

of observations, number of censored observations, and number of parameters in the regression model. Station locations are shown in figure 1]

Station name

Number

of 

observations

Regression coefficient Estimated

residual

variance

R2

(percent) a b c d e f g

Nitrite plus nitrate

Sinking Creek at Rosetta, Ky. 23 6.29 0.942 -0.078 -0.130 -0.204 0.153 -0.341 0.147 97

Sinking Creek near Lodiburg, Ky. 24 7.82 0.910 -0.069 -0.109 -0.061 0.156 -0.136 .060 99

Total phosphorus

Sinking Creek at Rosetta, Ky. 23 3.39 1.54 0.003 -0.711 -0.180 -0.037 0.081 .541 96

Sinking Creek near Lodiburg, Ky. 24 5.10 1.49 0.025 -0.601 -0.170 0.152 0.146 .186 98

Orthophosphate

Sinking Creek at Rosetta, Ky. 23 2.84 1.51 -0.147 -1.05 0.016 0.485 0.065 .412 97

Sinking Creek near Lodiburg, Ky. 24 4.27 1.27 -0.033 -0.746 -0.180 0.277 0.042 .186 97

Suspended sediment

Sinking Creek at Rosetta, Ky. 21 9.10 1.75 0.100 -0.274 -1.30 -0.113 -0.881 .842 96

Sinking Creek near Lodiburg, Ky. 20 11.2 1.97 -0.005 -0.576 -0.773 -0.162 -0.275 .354 99
Concentrations, and Estimated Loads and Yields of Nutrients 23

NATURAL LOG ESTIMATED LOAD OF NUTRIENT, IN POUNDS PER DAY,

SINKING CREEK NEAR LODIBURG

NATURAL LOG MEASURED LOAD OF NUTRIENT,

IN POUNDS PER DAY

1:1 line

NATURAL LOG ESTIMATED LOAD OF NUTRIENT, IN POUNDS PER DAY,

SINKING CREEK AT ROSETTA

NATURAL LOG MEASURED LOAD OF NUTRIENT,

IN POUNDS PER DAY

NATURAL LOG MEASURED LOAD OF NUTRIENT,

IN POUNDS PER DAY

Nitrite plus nitrate Nitrite plus nitrate

Orthophosphate Orthophosphate

Total phosphorus Total phosphorus

0 1 2 3 4 5 6 7 8 9 -4 -3 -2 -1 0 1 2 3 4 5 6

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

7

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

0 1 2 3 4 5 6 7 8 9 0

1

2

3

4

5

6

7

8

9

0

1

2

3

4

5

6

7

8

9

0

1

2

3

4

5

6

7

8

9

0

1

2

3

4

5

6

7

8

9

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Figure 10. Relation between estimated and measured loads of nitrite plus nitrate, orthophosphate, and total phosphorus at two 

Sinking Creek mainstem stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006.

Figure 10. Relation between estimated and measured loads of nitrite plus nitrate, total phosphorus, and orthophosphate at 

two Sinking Creek mainstem stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
24 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Occurrence, Distribution, 

Concentrations, and Estimated Loads 

and Yields of Select Pesticides

Summary statistics for the concentrations of pesticides 

from April 2004 through November 2004, March 2005 

through December 2005 at all sampling stations (Sinking 

Creek at Rosetta; Sinking Creek near Lodiburg; Big Spring; 

Flat Rock Spring; Boiling Spring; Ross Karst Window; 

and Fiddle Spring), and April 2006 through June 2006 at 

all stations except Boiling Spring and Ross Karst Window 

are presented in table 10. Results for seven compounds 

in all the samples collected and analyzed are provided in 

appendix 2. These data provide the basis for the occurrence 

and distribution and variability by station and season of select 

pesticides at all sampling stations and estimated loads and 

yields of select pesticides at the Sinking Creek near Lodiburg 

and Sinking Creek at Rosetta stations. Water-quality criteria 

and guidelines were used to evaluate the potential effects of 

pesticides on human health and aquatic organisms.

Occurrence and Distribution of Select 

Pesticides

Detections and concentrations of pesticides in streams 

are influenced by many factors, including the amount of 

pesticide used, the environmental persistence of the pesticide, 

the solubility and absorptive properties, and the analytical 

methods used. The most commonly detected pesticides (5 of 

the 47 pesticides analyzed) were among the most heavily 

applied in the karst terrane of the Sinking Creek Basin. 

Samples from all 7 stations had detectable concentrations of at 

least 1 pesticide; 1 sample collected at the Ross Karst Window 

station had 10 pesticides detected. Atrazine (24.6 μg/L), 

simazine (2.68 μg/L), acetochlor (2.85 μg/L), and metolachlor 

(1.55 μg/L) had the highest detected concentrations in 

the basin of the 11 herbicides detected (table 10). These 

herbicides are row‐crop herbicides and are the most heavily 

applied pesticides in the basin. Median concentrations of the 

herbicides—acetochlor, atrazine, metolachlor, and simazine—

ranged from <0.005 μg/L for simazine to 0.079 μg/L for 

atrazine for all samples collected during this study (table 10). 

A common method reporting level (MRL) of 0.01 μg/L was 

used to compare the detection frequencies of pesticides, 

because MRLs vary widely from one pesticide or related 

compound to another. Of the 47 pesticides analyzed, 14 were 

detected above the adjusted MRL of 0.01 μg/L (table 11). The 

use of the detection threshold allows for comparisons among 

pesticides by censoring detections to a common reference 

concentration. The lowest appropriate MRL for comparing 

pesticides is 0.01 μg/L for most of the pesticides analyzed 

in this study; however, prometon, pendimethalin, carbaryl, 

and malathion had MRLs that were greater than or equal to 

0.01 μg/L. For these pesticides, the detection frequency is 

preceded by the asterisk (*) symbol to indicate that the true 

percentage of samples with concentrations greater than the 

threshold probably is greater than or equal to that reported in 

figure 6.

Herbicides were detected more frequently than 

insecticides. Eleven of the 14 pesticides detected in water were 

herbicides. The commonly used herbicides, atrazine, simazine, 

metolachlor, acetochlor, and prometon, were found throughout 

the basin. Atrazine was detected in 97 percent of all 

surface‐water samples. Simazine was detected in 60 percent, 

and metolachlor and acetochlor were detected in more than 

30 percent of all surface-water samples (fig. 11). Almost 

30 percent of the atrazine and 11 percent of the simazine 

samples were in the 0.1 to 1.0 μg/L range. The pesticide 

transformation compound deethylatrazine (DEA) was detected 

in 93 percent of the samples; however, the method recovery 

for DEA is poor, so actual concentrations may be higher 

than reported. Only one nonagricultural herbicide, prometon, 

was detected in about 17 percent of the samples. Less 

frequently detected herbicides (less than 10-percent detection 

frequency) were alachlor, dieldrin, metribuzin, napropamide, 

pendimethalin, and propachlor. The insecticides carbaryl, 

a carbamate, and malathion, an organophosphate, were the 

only insecticides detected at any of the stations. Carbaryl, 

the most commonly detected insecticide, was found in about 

14 percent of the samples and was detected at all stations in 

the late spring and early summer (May through July) during 

storm events. Carbaryl was most frequently detected at the 

Sinking Creek at Lodiburg station and was detected 5 out 

of 63 samples. Malathion was detected in about 2 percent 

of the samples. The lower use of insecticides relative to 

herbicides and their application during periods of reduced 

runoff probably account for lower detection rates and low 

concentrations of insecticides in the basin.
Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of Select Pesticides 25

Table 10. Summary statistics of the detected herbicides and insecticides in samples collected at the sampling stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06; laboratory reporting levels, drinking-water standards, and aquatic-life criteria.[Drinking water standards are from U.S. Environmental Protection Agency (2004b), unless otherwise noted. Concentrations in micrograms per liter (μg/L). Abbreviations: E, estimated value (for low concentrations, the compound detected, but below the reporting limit; for high concentrations, the compound was detected above the range of the analytical method); MCL, maximum contaminant level; HAL, health advisory level; Ky, Kentucky; CIAT, 2-chloro-4-isopropylamino-6-amino-s-triazine. Symbol: –, no regulation or guideline]

Compound

Laboratory 

reporting level

 (μg/L)

Median 

concentration 

detected 

(μg/L)

95th

percentile 

detected

Maximum 

concentration 

detected 

(μg/L)

Station of maximum concentration

Drinking water 

standard guideline 

(MCL or HAL) 

(μg/L)

Aquatic-Life 

Benchmark 

(chronic aquatic 

community) 

(μg/L)

Herbicides

Acetochlor 0.006 0.03 1.07 2.85 Big Spring—F15CS004

–

–

Alachlor 0.005 0.082 0.171 0.186 Big Spring—F15CS004 2 –Atrazine 0.007 0.079 4.32 224.6 Sinking Creek at Rosetta, KY 3 11.8; 417.5Deethylatrazine (DEA) or (CIAT) 0.006 20.064 20.342 21.11 Big Spring—F15CS004

–

–

Metolachlor 0.006 0.036 0.466 1.55 Big Spring—F15CS004 3100 17.8Metribuzin 0.006 0.021 0.059 0.089 Big Spring—F15CS004 3200 11Napropamide 0.007 0.012 0.013 0.013 Sinking Creek near Lodiburg, KY

–

–

Pendimethalin 0.022 0.026 0.037 0.038 Sinking Creek at Rosetta, KY

–

–

Prometon 0.010 0.010 0.020 0.020 Sinking Creek at Rosetta, KY; Sinking 

Creek near Lodiburg, KY

3100

–

Propachlor 0.025 20.016 0.027 0.029 Fiddle Spring - F14DS007Simazine 0.005 0.030 0.708 2.68 Big Spring—F15CS004 4 –

Insecticides

Carbaryl .041 <.041 .041 .079 Fiddle Spring—F14DS007 700 1.20Malathion .027 <.027 .027 .211 Ross Karst window—F14DS003 200 0.1

1Canadian water-quality guidelines for the protection of freshwater aquatic life (Canadian Council of Ministers of the Environment, 2003).2Estimated value. 3U.S. Environmental Protection Agency lifetime-health advisory for a 70-kilogram adult (U.S. Environmental Protection Agency, 2004a).4U.S. Environmental Protection Agency aquatic-life benchmark table for chronic aquatic communities (U.S. Environmental Protection Agency, 2007).
26 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Figure 11. Occurrence of pesticide compounds from all samples at seven 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006. 

[Detection rates shown are relative to the common reference concentration of 0.01 ug/L.]

MALATHION

CARBARYL

PROMETON

ACETOCHLOR

METOLACHLOR

SIMAZINE

DEETHYLATRAZINE

ATRAZINE

DETECTION RATE, IN PERCENT

0 20 40 60 80 100

2006

2005

2004

Mean

ND No data

NDND

EXPLANATION

Figure 11. Occurrence of pesticide compounds from all samples at all stations in 

the karst terrane of the Sinking Creek Basin, Kentucky, study area, 2004–06.

Table 11. Pesticides and pesticide-transformation products 

analyzed in surface-water and groundwater samples from the 

karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.

[Bold-faced compounds were detected at the method reporting limit of 

0.01 μg/L; italicized compounds are pesticide-transformation products]

2,6-Diethylaniline Dieldrin Pebulate

Deethylatrazine 

(DEA) or 2-Chloro4-isopropylamino6-amino-s-triazine 

(CIAT)

Disulfoton Pendimethalin

Acetochlor EPTC Phorate

Alachlor Ethalfluralin Prometon

alpha-HCH Ethoprop Propyzamide

Atrazine Fonofos Propachlor

Azinphos-methyl Lindane Propanil

Benfluralin Linuron Propargite

Butylate Malathion Simazine

Carbaryl Methyl parathion Tebuthiuron

Carbofuran Metolachlor Terbacil

Chlorpyrifos Metribuzin Terbufos

cis-Permethrin Molinate Thiobencarb

Cyanazine Napropamide Triallate

DCPA pp’-DDE amide Trifluralin

Diazinon Parathion

Concentrations of Pesticides Compared to 

Drinking-Water Standards and Aquatic-Life 

Benchmarks

The USEPA has developed water-quality standards 

and benchmarks for some compounds that can have adverse 

effects on human health and aquatic organisms. Maximum 

contaminant levels (MCL) are standards established by 

the USEPA for finished drinking water delivered by public 

water systems. The MCL values provide a benchmark for 

comparison with sampled concentrations (U.S. Environmental 

Protection Agency, 2004a). Aquatic-life benchmarks provide 

for the protection of aquatic organisms for short-term (acute) 

and long-term (chronic) exposures to chemical compounds. 

In certain instances, Canadian benchmarks were used 

for comparisons when other criteria or benchmarks were 

unavailable (International Joint Commission Canada and 

United States, 1977; Canadian Council of Ministers of the 

Environment, 2003).

Most measured concentrations of pesticides during this 

study were less than existing drinking-water standards and 

benchmarks established for the protection of aquatic life 

(table 10). Only one pesticide compound—atrazine—exceeded 

the USEPA established MCL of 3 μg/L. Atrazine exceeded 

the established MCL in 8 percent of the samples. These 

exceedences occurred in the spring and were observed at four 
Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of Select Pesticides 27

of the seven sampling stations. Atrazine also was detected at 

concentrations exceeding benchmarks established to protect 

aquatic life (International Joint Commission Canada and 

United States, 1977; Canadian Council of Ministers of the 

Environment, 2003; U.S. Environmental Protection Agency, 

2007) (table 10). Concentrations of atrazine exceeded its 

aquatic-life benchmarks of 1.8 μg/L in 13 samples collected 

from 4 of the 7 sampling stations. The concentration of 

atrazine in the storm event sample collected from the Sinking 

Creek at Rosetta station, 24.6 μg/L, was more than 12 

times the Canadian aquatic-life benchmarks and exceeded 

the USEPA benchmarks for chronic effects on aquatic 

communities (table 10). Most of the high concentrations of 

atrazine occurred in storm event samples. Concentrations of 

the insecticide malathion exceeded its aquatic-life benchmark 

of 0.1 μg/L in two samples collected from the Ross Karst 

Window station and Flat Rock Spring station in August 2004.

Spatial Variability of Select Pesticides

Factors such as soil type, pesticide application rates, 

and the use of pesticides can affect the spatial variability 

of concentrations of pesticides. A detailed analysis of these 

factors, among others, is beyond the scope of this report. 

The nonparametric statistical tests (Kruskal-Wallis and 

Wilcoxon rank-sum) were used to examine select pesticide 

concentrations for significant differences among the sampling 

stations. The Kruskal-Wallis test does not determine which 

medians of the select pesticide concentrations at the stations 

are different, so the Wilcoxon rank-sum test was used to 

determine which stations had significantly different select 

pesticide concentrations. Differences between the groups 

of data with a probability (p) value of 0.05 or less were 

considered significant. 

Significant differences (Kruskal-Wallis, p-value = 0.006) 

in concentrations of atrazine occurred among the sampling 

stations, with pair-wise comparisons (Wilcoxon rank-sum) 

showing that concentrations of atrazine were statistically 

smaller at the Fiddle Spring station than at all stations, 

except at the Sinking Creek at Rosetta station (fig. 12). A 

possible explanation is that the Fiddle Spring station has 

a different recharge area from these stations, and the land 

use/land cover has minimal cultivated agricultural land. No 

statistical differences were found among the concentrations 

of atrazine at the other stations. Results of the Krusal-Wallis 

test for concentrations of deethylatrazine, the transformation 

compound of atrazine (p-value = <0.001), indicated significant 

differences among the stations. The Wilcoxon rank-sum test 

showed that concentrations of deethylatrazine at the Sinking 

Creek at Rosetta station and the Fiddle Spring station were 

statistically less than concentrations of deethylatrazine at the 

other stations. Lesser concentrations of deethylatrazine at the 

Sinking Creek at Rosetta station and the Fiddle Spring station 

are likely related to the small amount of cultivation in their 

drainage areas.

Significant differences (Kruskal-Wallis, p-value = 0.006) 

in concentrations of simazine occurred among the sampling 

stations, with pair-wise comparisons (Wilcoxon rank-sum) 

showing that concentrations of simazine were statistically 

less at the Fiddle Spring station than the other stations, except 

at the Sinking Creek at Rosetta station (fig. 12). Lesser 

concentrations of simazine at the Fiddle Spring station are 

likely related to less cultivation in its recharge area. No 

significant differences between the stations and concentrations 

of acetochlor or metoachlor were dedected at the 95-percent 

confidence level.

Seasonal Variability of Select Pesticides

Concentrations of pesticides varied throughout the 

year in samples collected at all sampling stations, and the 

highest concentrations generally were found during the spring 

(fig. 13). The maximum concentrations of select herbicides 

detected—acetochlor, atrazine, metolachlor, and simazine— 

occurred in the growing season (April–May) (fig. 13). The 

pesticides detected above the adjusted MRL of 0.01 μg/L in 

the karst terrane of the Sinking Creek Basin were found in 

Sinking Creek and surrounding springs and karst windows 

year around, but at smaller concentrations (table 10). The most 

commonly detected insecticide, carbaryl, also was present 

primarily in the spring. The highest concentrations of carbaryl, 

0.09 μg/L, occurred during May 2005. However, most 

detections of carbaryl were less than the 0.041 μg/L laboratory 

reporting level. Unlike carbaryl, malathion was detected 

only in the summer of 2005, and the highest concentration 

was 0.211 μg/L. Median concentrations of these two most 

commonly detected insecticides in the karst terrane of the 

Sinking Creek Basin were less than their reporting levels.

Concentrations of atrazine and its transformation 

compound, deethylatrazine, in relation to daily mean 

streamflow at the Sinking Creek near Lodiburg station and 

Sinking Creek at Rosetta station are shown in figure 14. 

Concentrations of the parent pesticide compound, atrazine, 

were higher in the spring following application during periods 

of increased streamflow and lower later in the growing season 

when it is not applied and streamflow is decreased. The 

seasonal pattern for the pesticide transformation compound, 

deethylatrazine, mirrored that of its parent compound, 

atrazine, but generally at lower concentrations. Pesticide 

transformation compounds generally cooccur with parent 

pesticide compounds, because most pesticides begin to 

degrade by chemical or biological processes immediately 

following application.
28 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

(27)

SINKING

CREEK

NEAR

LODIBURG

(11)

BOILING

SPRING

F14CS002

(16)

FIDDLE

SPRING

F14DS007

(19)

FLAT 

ROCK

SPRING

F14DS005

(14)

ROSS

KARST

WINDOW

F14DS004

(19)

BIG 

SPRING

F15CS004

(23)

SINKING

CREEK

AT 

ROSETTA

Data outside

10th and 90th percentile

90 percent

75 percent

Median

25 percent

10 percent

EXPLANATION

(23)Number of samples collected

Figure 12. Concentrations of select pesticides (acetochlor, atrazine, deethylatrazine, metolachlor, and simazine) at seven sampling stations

in the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006. CONCENTRATION, IN MICROGRAMS PER LITER

0.0

0.5

2.0

4.0

Simazine

0.0

0.5

2.0

3.0

Metolachlor

(27)

SINKING

CREEK

NEAR

LODIBURG

(11)

BOILING

SPRING

F14CS002

(16)

FIDDLE

SPRING

F14DS007

(19)

FLAT 

ROCK

SPRING

F14DS005

(14)

ROSS

KARST

WINDOW

F14DS004

(19)

BIG 

SPRING

F15CS004

(23)

SINKING

CREEK

AT 

ROSETTA

0

2

9

16

23

30

Atrazine

Deethylatrazine

0.0

0.5

2.0

4.0

Acetochlor

Figure 12. Concentrations of acetochlor, atrazine, deethylatrazine, metolachlor, and simazine at all sampling stations in the 

karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of Select Pesticides 29

0.0

0.1

0.2

0.3

0.4

0.5

Simazine

0.0

0.1

0.2

0.3

Metolachlor

0

1

2

3

4

Deethylatrazine

0

1

2

3

4

Atrazine

(20)

(8)

(7)

(10)

(16) (13) (14) (7) (6)

(28)

0.0

0.1

0.2

0.3

0.4

0.5

Acetochlor

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

AUGUST

SEPTEMBER

OCTOBER

NOVEMBERDECEMBER

Figure 13. Monthly distribution of select pesticides at seven sampling stations in the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004-2006.

JULY

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

AUGUST

SEPTEMBER

OCTOBER

NOVEMBER

DECEMBER

JULY

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

AUGUST

SEPTEMBER

OCTOBER

NOVEMBERDECEMBER

JULY

MONTHLY MEAN CONCENTRATIONS, IN MICROGRAMS PER LITER

(20)

(8) (7) (10)

(16) (13) (14) (7) (6)

(28)

(20)

(8)

(7) (10) (16)

(13) (14) (7) (6)

(28)

(20)

(8)

(7)

(10) (16) (13) (14) (7) (6)

(28)

(20) (8)

(7)

(10)

(16) (13) (14) (7) (6)

(28)

MONTHLY MEAN CONCENTRATIONS, IN MICROGRAMS PER LITER

Figure 13. Monthly distribution of select pesticides at seven sampling stations in the karst terrane of the Sinking Creek Basin, 

Kentucky, 2004–06.
30 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Figure 14. Seasonal variability of atrazine and its transformation 

product, deethylatrazine, at the Sinking Creek at Rosetta and the 

Sinking Creek near Lodiburg stations in the karst terrane of the Sinking 

Creek Basin, Kentucky, 2004–06.

Estimated Loads and Yields of Select Pesticides

Water-resource managers often need to know the amount of 

a contaminant transported in a stream to determine the stream’s 

condition and how it changes over time. Loads and yields of the 

contaminants are common measures for these assessments. Load 

represents the mass, usually expressed in pounds or tons, of a given 

constituent moving past a given point per unit time, and yield 

represents the load for a unit area. Loads and yields were estimated 

for the four select pesticides and one transformation compound 

frequently detected in samples for the Sinking 

Creek at Rosetta station and the Sinking Creek near 

Lodiburg station from samples collected in 2004, 

2005, and 2006 (table 12). The ratio of the standard 

error of prediction to the mean load standardizes the 

model error and provides a comparison among the 

load estimates at the two stations. In general, the 

regression model errors for pesticides at the Sinking 

Creek at Rosetta station were greater than the 

regression model errors for pesticides at the Sinking 

Creek near Lodiburg station. Because the daily mean 

streamflow was estimated at the Sinking Creek at 

Rosetta station, the error in the estimated nutrient 

loads at this station is larger than that determined by 

the S-LOADEST model alone, because it includes 

considerable and unknown biases and imprecision in 

the streamflow estimates. Loads were not estimated 

at the karst window or spring stations, because a 

streamflow relation between these stations and the 

Sinking Creek near Lodiburg station could not be 

established.

Mean annual loads, in pounds per year, 

for select pesticides were estimated using the 

S-LOADEST program. Load estimates based on 

sampling stations with long periods of record are 

more reliable than estimates from stations with short 

periods of record. Annual loads vary depending on 

drainage basin size, discharge conditions, and land 

uses.

The coefficients of determination (R2) for the 

best-fit regression models for loads of the select 

pesticides are listed in table 13. High R2 values 

indicate that the models for the select pesticides 

reasonably simulated the variability in constituent 

loads at the two Sinking Creek mainstem stations. 

Measured instantaneous loads of select pesticides 

for the two Sinking Creek mainstem stations were 

plotted against estimated loads for the same day 

to visually assess the fitness of the model (fig. 15). 

Points above the 1:1 line indicate that the model 

underestimated the loads; points below the line 

indicate the model overestimated the loads. The 

relation between estimated and measured loads of 

atrazine at both Sinking Creek mainstem stations 

suggests that the model overestimated the loads 

of atrazine at these stations. Relations between 

estimated and measured loads of deethylatrazine 

and simazine at the Sinking Creek near Lodiburg 

0.01

0.1

1

10

100

CONCENTRATION, IN MICROGRAMS PER LITER

Sinking Creek near Lodiburg

CONCENTRATION, IN MICROGRAMS PER LITER

1

10

100

1,000

10,000

ESTIMATED STREAMFLOW, IN CUBIC FEET PER SECOND

0.001

0.01

0.1

1

10

100

Estimated continuous streamflow

Deethylatrazine

Atrazine

Sinking Creek at Rosetta

1

10

100

1,000

10,000

STREAMFLOW, IN CUBIC FEET PER SECOND

Continuous streamflow

Deethylatrazine

Atrazine

M J J A S O N D J F M A M J J A S O N D J F M A M J

2004 2005 2006
Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of Select Pesticides 31

station indicate a reasonably tight distribution near the 1:1 line 

over the range of loads (fig. 15) and suggest that the model 

had a reasonably good fit; however, the modeled loads of 

deethylatrazine and simazine at the Sinking Creek at Rosetta 

station show a much poorer fit of the model. The model for 

the loads of metolachlor at the Sinking Creek near Lodiburg 

station indicates a reasonable relation between estimated and 

measured loads; however, the plot shows the model was not as 

successful in estimating large loads (fig. 15). 

The Sinking Creek near Lodiburg station had the 

highest mean annual loads of acetochlor (72 lb/yr), atrazine 

(1,020 lb/yr), metolachlor (35 lb/yr), and simazine (12 lb/yr) 

from 2004 through spring of 2006 (table 12). The estimated 

load of atrazine at the Sinking Creek at Rosetta station of 73 

lb/yr was about 7 percent of the atrazine load at the Sinking 

Creek near Lodiburg station of 1,020 lb/yr.

The estimated annual loads of acetochlor, atrazine, 

metolachlor, and simazine in the karst terrane of the Sinking 

Creek Basin during the study period were less than 0.01 to 

1.2 percent of the amount of assumed applications in the basin. 

The large variability in the values for load as a percentage of 

use is to be expected because of the considerable variability 

in physical properties and application practices (Larson and 

others, 1997).

The Sinking Creek near Lodiburg station had higher 

yields of the commonly used row-crop herbicides acetochlor, 

atrazine, deethylatrazine, and metolachlor than the Sinking 

Creek at Rosetta station. The yield of atrazine upstream from 

the Sinking Creek at Lodiburg station was 8.2 (lb/yr)/mi2; 

acetochlor and metolachlor yields were 0.58 (lb/yr)/mi2 and 

0.28 (lb/yr)/mi2, respectively (table 12). Simazine, another 

commonly used row-crop herbicide, had a slightly higher yield 

at the Sinking Creek at Rosetta station, 0.08 (lb/yr)/mi2, than 

at the Lodiburg station, 0.03 (lb/yr)/mi2. 

Table 12. Estimated mean annual load and yield of five select pesticides at two Sinking Creek mainstem 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.

[Abbreviations: lb/yr, pound per year; (lb/yr)/mi2, pound per year per square mile; DA, drainage area; mi2, square mile. 

Symbol: <, less than]

Pesticide

Estimated 

mean annual 

load

(lb/yr)

Standard

error of 

prediction

Prediction 

of error

(percent)

Mean annual 

yield 

[(lb/yr)/mi2]

Sinking Creek at Rosetta, Ky.

(DA = 36 mi2)

Acetochlor 4.4 4.2 95 0.12

Atrazine 73 110 151 2.0

Deethylatrazine 5.8 1.9 53 0.16

Metolachlor 5.5 7.3 133 0.15

Simazine 2.8 11 393 0.08

Sinking Creek near Lodiburg, Ky.

(DA = 125 mi2)

Acetochlor 72 137 190 0.58

Atrazine 1,020 370 36 8.2

Deethylatrazine 37 7.6 21 0.29

Metolachlor 35 30 86 0.28

Simazine 12 6.1 51 0.03
32 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06 Table 13. Regression coefficients and coefficients for determination (R2) for load models used to estimate the loads of five select pesticides at two stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06. [Estimated residual variance is the maximum likelihood estimation variance corrected for the number of observations, number of censored observations, and number of parameters in the regression model. The regression equation is ln(L)=a + b(lnQ) + c(ln

Q2) + d[sin(2πT)] + e[cos(2πT)]+ 

fT +gT2 where L is the constituent load, in pounds per day; Q is stream discharge, in cubic feet per second; T is time in decimal 

years from the beginning of the calibration period; a, b ,c ,d ,e, f, g are regression coefficients; R2 represents the amount of variance explained by the model. Station locations are shown in figure 1.]

Station name

Regression coefficient

R2

(percent) Number of

observations a b c d e f g

Estimated

residual

variance

Acetochlor

Sinking Creek at Rosetta, Ky. 23 -6.46 1.40 0.649 -1.97 1.40 91Sinking Creek near Lodiburg, Ky. 24 -5.32 1.63 0.646 -2.74 2.63 89

Atrazine

Sinking Creek at Rosetta, Ky. 23 -3.88 1.01 -0.041 -2.48 -0.022 3.47 73Sinking Creek near Lodiburg, Ky. 24 -1.81 1.23 .510 -1.36 0.578 1.65 87

Deethylatrazine

Sinking Creek at Rosetta, Ky. 23 -4.48 1.02 -0.183 -1.06 -0.112 0.736 90Sinking Creek near Lodiburg, Ky. 24 -2.59 1.04 -.072 -.714 0.149 0.390 94

Metolachlor

Sinking Creek at Rosetta, Ky. 23 -7.71 1.29 1.00 -3.53 -0.856 1.29 94Sinking Creek near Lodiburg, Ky. 24 -3.87 1.48 -0.180 -0.874 0.724 1.22 90

Simazine

Sinking Creek at Rosetta, Ky. 23 -6.20 0.943 0.004 0.416 -1.82 0.798 -0.094 2.78 77Sinking Creek near Lodiburg, Ky. 24 -5.59 0.901 0.140 0.676 -1.51 0.470 0.741 0.600 94
Occurrence, Distribution, Concentrations, and Estimated Loads and Yields of Select Pesticides 33

Figure 15. Relation between estimated and measured loads of select pesticides at two Sinking Creek mainstem stations in the karst

terrane of the Sinking Creek Basin, Kentucky, 2004-2006.

Atrazine

Deethylatrazine

Metolachlor

Simazine

Atrazine

Deethylatrazine

Metolachlor

Simazine

NATURAL LOG ESTIMATED LOAD OF PESTICIDE, IN POUNDS PER DAY,

SINKING CREEK NEAR LODIBURG

NATURAL LOG ESTIMATED LOAD OF PESTICIDE, IN POUNDS PER DAY,

SINKING CREEK AT ROSETTA

0 1 2 3 4 5 6 7 8 9

1:1 line

NATURAL LOG MEASURED LOAD OF PESTICIDE,

IN POUNDS PER DAY

NATURAL LOG MEASURED LOAD OF PESTICIDE,

IN POUNDS PER DAY

NATURAL LOG MEASURED LOAD OF PESTICIDE,

IN POUNDS PER DAY

NATURAL LOG MEASURED LOAD OF PESTICIDE,

IN POUNDS PER DAY

-4 -3 -2 -1 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

-4 -3 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

-2

-1

0

1

2

3

4

5

6

7

8

9

10

11

-2

-1

0

1

2

3

4

5

6

7

8

-4

-3

-2

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

-4

-3

-2

-1

0

1

2

3

4

5

6

7

8

9

-4

-3

-2

-1

0

1

2

3

4

5

6

7

8

-4

-3

-2

-1

0

1

2

3

4

5

6

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

-4 -3 -2 -1 0 1 2 3 4 5 6

-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8

-2 -1 0 1 2 3 4 5 6 7 8

-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Figure 15. Relation between estimated and measured loads of select pesticides at two Sinking Creek mainstem 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
34 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Concentrations and Estimated Loads 

and Yields of Suspended Sediment

Summary statistics are computed in table 7 for the 

concentrations of suspended sediment from April 2004 

through November 2004, March 2005 through December 

2005 at all sampling stations (Sinking Creek at Rosetta; 

Sinking Creek near Lodiburg; Big Spring; Flat Rock Spring; 

Boiling Spring; Ross Karst Window; and Fiddle Spring), and 

April 2006 through June 2006 at all stations except Boiling 

Spring and Ross Karst Window. Additional high-flow event 

samples of suspended sediment were collected at the Sinking 

Creek near Lodiburg station with an automatic sampler. The 

results of all the samples collected and analyzed are provided 

in appendix 1. These data provide the basis for analysis of 

concentrations at the selected sampling stations and the loads 

and yields at the Sinking Creek near Lodiburg and Sinking 

Creek at Rosetta stations.

Concentrations of Suspended Sediment

Suspended sediment is all particulate matter suspended 

in the water column resulting from streambed resuspension, 

rock weathering, and soil erosion. Although streams transport 

sediments, anthropogenic impacts such as construction, 

timber harvesting, and certain agricultural practices can 

increase sediment transport. High concentrations of suspended 

sediment can cause habitat destruction and limit light 

penetration throughout the water column (Osterkamp and 

others, 1998). In addition, suspended sediment plays a major 

role in the transport and fate of contaminants and pathogens. 

Contaminants and pathogens may sorb onto the surface of the 

suspended sediments and be transported and deposited in other 

areas downstream (Horowitz, 1991; Rasmussen and Ziegler, 

2003).

Spatial Variability of Suspended Sediment

Concentrations of suspended sediment for all hydrologic 

conditions ranged from 1 mg/L at multiple stations to 

1,490 mg/L at the Sinking Creek near Lodiburg station in 

karst terrane of the Sinking Creek Basin (fig. 16). When 

storm-event samples collected by the automatic sampler were 

excluded, the median concentration of suspended sediment 

for all stations sampled was 15 mg/L. When storm-event 

samples collected by the automatic sampler were included, the 

median concentration of suspended sediment was 73 mg/L. 

The highest concentration of suspended sediment, 1,490 mg/L, 

was measured at the Sinking Creek near Lodiburg station 

during an early summer runoff event (fig. 16). The KruskalWallis test (p-value = 0.552) performed on concentrations of 

suspended sediment indicate no significant differences among 

the stations.

Figure 16. Concentrations of suspended sediment at all sampling stations in the karst 

terrane of the Sinking Creek Basin, Kentucky, 2004–06.

Data outside

10th and 90th percentile

90 percent

75 percent

Median

25 percent

10 percent

EXPLANATION

(21)Number of samples collected

(21) Sinking Creek at Rosetta

(18) Big Spring F15CS004

(13) Ross Karst Window F14DS004

(18) Flat Rock Spring F14DS005

(15) Fiddle Spring F14DS007

(12) Boiling Spring F14CS002

(22) Sinking Creek near Lodiburg(35) Sinking Creek near Lodiburg

0

400

800

1200

1600

2000

CONCENTRATION, IN MILLIGRAMS PER LITER

Samples from

automatic 

sampler

Suspended sediment
Concentrations and Estimated Loads and Yields of Suspended Sediment 35

Hydrologic Variability of Suspended Sediment

Concentrations of suspended sediment were higher in the 

spring (March through May) and winter (December through 

February) than in summer (June through August) and autumn 

(September through November) (fig. 17). Results from the 

Kruskal-Wallis test (p-value = <0.001) for concentrations of 

suspended sediment indicate a statistical difference among 

seasons. The Wilcoxon rank-sum test showed concentrations 

of suspended sediment were less in autumn compared with the 

concentrations of suspended sediment in the other seasons. 

Streamflow is typically lower in autumn than any other time 

of the year. No statistical differences were found among the 

concentrations of suspended sediment in spring, summer, and 

winter. Increases in precipitation in the spring, winter, and 

during thunderstorms in the summer allow for the runoff of 

sediment into the streams.

Estimated Loads and Yields of Suspended 

Sediment

Mean annual loads [(in/lb)/yr] for suspended sediment 

were estimated using the S-LOADEST program at the two 

Sinking Creek mainstem sampling stations from samples 

collected from 2004 through spring 2006 (table 8). Because 

the daily mean streamflow was estimated at the Sinking Creek 

at Rosetta station, the error in the estimated nutrient loads at 

this station is larger than that determined by the S-LOADEST 

model alone, because it includes considerable and unknown 

biases and imprecision in the streamflow estimates. Loads 

were not estimated at the springs or karst window station, 

because of the absence of continuous streamflow data.

The coefficients of determination (R2) for the best‐fit 

regression models for loads of suspended sediment are 

listed in table 9. High R2 values indicate that the models for 

suspended sediment reasonably simulated the variability in 

constituent loads at the two Sinking Creek mainstem stations. 

Measured instantaneous loads of suspended sediment for the 

two Sinking Creek mainstem stations were plotted against 

estimated loads for the same day to visually assess the fitness 

of the model (fig. 18). Relations between the estimated and 

measured loads of suspended sediment at the Sinking Creek 

near Lodiburg station indicate a reasonably tight distribution 

near the 1:1 line over the range of loads (fig. 18); thus, 

suggesting that the model had a reasonably good fit. The 

modeled loads of suspended sediment at the Sinking Creek 

at Rosetta station indicate overestimations of loads at smaller 

loads (fig. 18). The estimated mean annual loads of suspended 

sediment at the Sinking Creek at Rosetta station and the 

Sinking Creek near Lodiburg station were 10,300,000 and 

143,000,000 lb/yr, respectively (table 8). The estimated mean 

annual load of suspended sediment is about 14 times larger at 

the Sinking Creek near Lodiburg station than at the Sinking 

Creek near Rosetta station. The yield of suspended sediment 

at the Sinking Creek near Lodiburg station is about four times 

greater than at the Sinking Creek at Rosetta station. The 

difference indicates a possible increase in yield from a source, 

such as streambank retreat, and supports the concept that landcover or land-use changes or both increase streamflows that 

may result in higher rates of streambank retreat. Other possible 

sources of sediment include collapse of a swallow hole, or 

widening of a sinkhole.

Figure 17. Seasonal distribution of suspended sediment concentrations at seven sampling stations in

the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006.

0

200

400

600

800

1000

1200

1400

1600

CONCENTRATION, IN MILLIGRAMS PER LITER

Data outside

10th and 90th percentile

90 percent

75 percent

Median

25 percent

10 percent

EXPLANATION

SPRING SUMMER AUTUMN WINTER

Figure 17. Seasonal distribution of suspended sediment concentrations at seven sampling 

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
36 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Summary and Conclusions

A water-quality assessment of springs, karst windows, 

and streams in the karst terrane of the Sinking Creek Basin, 

also known as the Boiling Spring Basin, was conducted from 

April 2004 through November 2004, March 2005 through 

December 2005, and April 2006 through June 2006, in 

cooperation with the Kentucky Department of Agriculture. 

The monitoring network consisted of two stations on the 

mainstem of Sinking Creek, Sinking Creek at Rosetta, which 

has a 35-square mile drainage area, and Sinking Creek near 

Lodiburg, which has a 125-square mile drainage area; four 

spring stations, Big Spring, Flat Rock Spring, Fiddle Spring, 

and Boiling Spring; and one karst window station, Ross 

Karst Window. Water samples were analyzed for nutrients, 

pesticides, and suspended sediment. Nutrient, select pesticide 

(5 of the 47 pesticides analyzed), and suspended-sediment 

data were used to estimate loads and yields from the two 

mainstem Sinking Creek monitoring stations. A mathematical 

record-extension technique known as the Maintenance of 

Variance-Extension, type 1 (MOVE.1) technique was used 

to estimate streamflow for the partial-record station, Sinking 

Creek at Rosetta, by use of data from the nearby gaging 

station Sinking Creek near Lodiburg. Large uncertainty exists 

in the estimated daily streamflows at the partial-record station, 

because (1) only instantaneous streamflow measurements 

were available at the partial-record station; (2) the drainage 

area at the partial-record station is about 29 percent of the 

drainage area of the streamgaging station; and (3) the partialrecord station is a headwater station indicating streamflow 

response to precipitation events is usually quicker than at 

downstream stations. Additional streamflow data were used 

to support the use of the MOVE.1 technique in extending the 

streamflow record at the partial-record station. Because the 

daily mean streamflow was estimated at the Sinking Creek 

at Rosetta station, the error in the estimated nutrient, select 

pesticide, and suspended-sediment loads at this station are 

subject to considerable and unknown biases and imprecision 

(greater standard error of predictions than reported); thus, the 

reliability of the results is affected. Additional streamflow 

and water-quality data are needed to improve the reliability of 

the load estimates and the errors associated with them at the 

upstream and downstream stations on Sinking Creek. Loads 

were not estimated at the karst window or spring stations, 

because a streamflow relation between these stations and the 

mainstem stations could not be established.

Concentrations of nitrite plus nitrate ranged from 0.21 to 

4.9 milligrams per liter (mg/L) at the seven stations. The 

highest concentration of nitrite plus nitrate of 4.9 mg/L was 

observed at the Big Spring station. The lowest concentration 

of nitrite plus nitrate of 0.21 mg/L was observed at the 

Sinking Creek at Rosetta station. The median concentration 

of nitrite plus nitrate for all stations sampled was 1.6 mg/L. 

Total phosphorus concentrations were greater than 0.1 mg/L, 

the U.S. Environmental Protection Agency’s recommended 

maximum concentration, in 45 percent of the samples. The 

median concentration of total phosphorus for all stations 

sampled was 0.08 mg/L. Concentrations of orthophosphates 

ranged from <0.006 to 0.46 mg/L. The highest concentration 

of orthophosphate, 0.46 mg/L, was measured at the Big Spring 

station.

Concentrations of nutrients were generally larger during 

spring and summer months, corresponding to periods of 

increased fertilizer application on agricultural lands. Estimated 

Figure 18. Relation between estimated and measured loads of suspended sediment at two Sinking Creek mainstem

stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004-2006.

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

1:1 line

Sinking Creek

near Lodiburg

NATURAL LOG ESTIMATED LOAD OF SUSPENDED SEDIMENT, IN POUNDS PER DAY

NATURAL LOG MEASURED LOAD OF SUSPENDED 

SEDIMENT, IN POUNDS PER DAY

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

Sinking Creek 

at Rosetta

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Figure 18. Relation between estimated and measured loads of suspended sediment at two Sinking Creek 

mainstem stations in the karst terrane of the Sinking Creek Basin, Kentucky, 2004–06.
References Cited 37

mean annual yield of nitrite plus nitrate at the downstream 

monitoring station, Sinking Creek near Lodiburg, were two 

times larger than yields at the upstream monitoring station, 

Sinking Creek at Rosetta. The estimated mean annual yields 

of orthophosphate and total phosphorus at the downstream 

monitoring station were 1.5 and 3 times larger, respectively, 

than yields at the upstream monitoring station.

Herbicides were detected more frequently than 

insecticides at all seven monitoring stations. Eleven of 

the 14 pesticides detected in water were herbicides. The 

commonly used herbicides, atrazine, simazine, metolachlor, 

acetochlor, and prometon were found at all seven monitoring 

stations. Atrazine was detected in 97 percent of the 

129 surface-water samples for pesticides. The atrazine 

transformation compound, deethylatrazine, was detected 

in 93 percent of the samples. Prometon was the only 

nonagricultural herbicide detected. Carbaryl, carbofuran, and 

malathion were the only insecticides detected.

Most pesticides were present in less than part-perbillion concentrations. Atrazine and simazine, which are 

row-crop herbicides, had the highest measured concentrations 

of 24.6 and 2.68 micrograms per liter (μg/L), respectively, 

and were the most heavily applied herbicides in the basin. 

Atrazine was the only pesticide compound to exceed the 

U.S. Environmental Protection Agency standard for drinking 

water of 3 μg/L. Concentrations of atrazine, deethylatrazine, 

and simazine at the Fiddle Spring station generally were 

statistically smaller than those stations draining predominately 

cultivated agricultural land. Concentrations of pesticides 

generally were highest in the spring and correspond to the 

period of heaviest land application.

The estimated annual loads of acetochlor, atrazine, 

metolachlor, and simazine for the study period were less than 

0.01 to 1.2 percent of the amount assumed applied in the 

basin. Mean annual loads of atrazine of 1,020 pounds per year 

at the downstream Sinking Creek near Lodiburg station were 

larger than the 73 pounds per year at the Sinking Creek near 

Rosetta station.

The concentrations of suspended sediment ranged from 

1.0 to 1,490 mg/L at the seven stations. When storm-event 

samples collected by the automatic sampler were excluded, 

the median concentration of suspended sediment for the seven 

stations sampled was 15 mg/L. When storm-event samples 

collected by the automatic sampler were included, the median 

concentration of suspended sediment was 73 mg/L. The 

highest concentration of suspended sediment, 1,490 mg/L, was 

measured at the Sinking Creek near Lodiburg station during an 

early summer runoff event. The estimated mean annual yield 

of suspended sediment at the downstream monitoring station, 

Sinking Creek near Lodiburg, was about four times greater 

than the yield at the upstream monitoring station, Sinking 

Creek at Rosetta. The difference indicates a possible increase 

in yield from a source, such as streambank retreat, collapse of 

a swallow hole, or widening of a sinkhole.

Acknowledgments

Thanks are extended to members of the Sinking Creek 

Watershed Council, especially Ernest Collins, Kentucky 

Department of Agriculture; Rickey Miller, Breckinridge 

County Extension Service; Calvin Bohannon, Breckinridge 

and Meade County Conservation Districts; Tim Carden, 

Breckinridge County Extension District Board; Steve Gray, 

Kentucky Division of Forestry; Scott Harp, Kentucky 

Department of Fish & Wildlife Liaison; Angela Kessans and 

Kathy Ward, Kentucky Division of Water; Jill Bulter, Lincoln 

Resource Conservation and Development Council; and 

Bill Thom, University of Kentucky Cooperative Extension 

Service; and other members of the Sinking Creek Watershed 

Council for their technical assistance, expertise, and 

knowledge of local contacts to help organize and implement 

the field-day demonstrations. I also would like to thank 

Aimee Downs, USGS, for assistance with GIS illustrations 

and summarizing the agricultural crop sales data, and thank 

Casey Lee, Cherie Miller, and Timothy Willoughby, USGS, 

for technical colleague reviews. A special thanks to the land 

owners in the Sinking Creek Basin who provided access for 

water-sample collection.

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Appendix 1 41

Appendix 1. Station Name, Sample-Collection Date, Nutrient, and Suspended 

Sediment Results for Samples Collected in the Karst Terrane of the Sinking 

Creek Basin, Kentucky, 2004–06

[ft3/s, cubic feet per second; mg-L, milligrams per liter; E, estimated, <, less than; –, no data]

USGS station name USGS station No.

Samplecollection 

date

Discharge 

(ft3/s)

Ammonia

as N

(mg/L)

Nitrite plus 

nitrate as N 

(mg/L)

Orthophosphate as P 

(mg/L)

Total 

phosphorus 

(mg/L)

Suspended 

sediment 

(mg/L)

Sinking Creek at 

Rosetta, Ky

03303195 04-22-04 125 <0.04 0.81 0.015 0.066 26

05-27-04 2,080 <0.04 0.21 0.01 0.250 306

07-08-04 7.4 <0.04 1.06 E0.003 0.037 73

08-02-04 7.0 <0.04 1.02 0.008 0.023 4

09-07-04 17 <0.04 0.7 0.011 0.031 5

10-25-04 – <0.04 0.32 <0.006 0.023 3

11-22-04 – <0.04 1.21 0.101 0.151 11

03-16-05 29 <0.04 0.72 <0.006 0.017 2

03-28-05 1,000 0.05 0.69 0.034 0.220 251

04-12-05 35 <0.04 0.73 <0.006 E0.003 –

04-29-05 17 <0.04 0.85 <0.006 0.009 8

05-17-05 15 E0.03 0.98 0.01 0.049 15

05-20-05 428 0.08 1.49 0.047 0.260 274

06-14-05 8.7 E0.03 1.16 <0.006 0.028 –

07-13-05 14 E0.02 1.53 0.01 0.036 12

08-18-05 3.9 <0.04 0.85 E0.005 0.020 51

08-30-05 1,250 0.04 0.57 0.091 0.350 1,160

09-15-05 6.1 <0.04 0.88 E0.010 0.029 4

10-25-05 2.5 <0.04 0.54 E0.007 0.022 3

12-06-05 4.7 <0.04 1.25 E0.003 0.019 1

04-17-06 22 <0.04 0.56 <0.006 0.011 6

05-11-06 36 – – – – 6

05-26-06 2,140 <0.010 0.41 0.038 0.220 358

06-21-06 14 0.018 0.93 0.025 0.046 9

Sinking Creek near 

Lodiburg, Ky

03303205 04-22-04 333 <0.04 1.29 0.014 0.096 106

05-25-04 1,160 <0.04 1.34 0.072 0.420 414

05-27-04 5,260 <0.04 0.35 0.037 0.400 563

07-08-04 44 <0.04 2.04 0.042 0.070 67

07-12-04 – – – – – 1,490

07-12-04 – – – – – 647

08-02-04 38 <0.04 2.17 0.071 0.101 19

09-07-04 20 <0.04 1.33 0.054 0.086 8

10-25-04 16 <0.04 1.14 0.043 0.070 5

11-22-04 – <0.04 2.15 0.061 0.094 34

03-16-05 110 <0.04 1.48 0.017 0.030 8

03-28-05 4,240 0.11 0.96 0.065 0.540 1,060

04-12-05 184 <0.04 1.6 0.02 0.042 –

04-29-05 79 <0.04 1.6 0.019 0.037 14

05-17-05 59 <0.04 1.62 0.017 0.042 10

05-19-05 – – – – – 1,020

05-20-05 – 0.13 1.84 0.037 0.630 –

05-20-05 – – – – – 1,270

05-20-05 – 0.27 1.79 0.046 0.590 1,070

05-20-05 – – – – – 886

05-20-05 2,360 0.16 1.76 0.093 0.480 811
42 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

USGS station name USGS station No.

Samplecollection 

date

Discharge 

(ft3/s)

Ammonia

as N

(mg/L)

Nitrite plus 

nitrate as N 

(mg/L)

Orthophosphate as P 

(mg/L)

Total 

phosphorus 

(mg/L)

Suspended 

sediment 

(mg/L)

Sinking Creek near 

Lodiburg, Ky—Cont.

03303205 05-20-05 – – – – – 629

05-20-05 – – – – – 493

05-20-05 – 0.09 1.76 0.056 0.420 436

05-21-05 – – – – – 364

05-21-05 – – – – – 365

06-14-05 41 <0.04 2.2 0.03 0.068 –

07-13-05 136 <0.04 1.84 0.091 0.230 93

08-18-05 17 <0.04 1.67 0.044 0.064 24

08-30-05 897 0.09 1.39 0.109 0.440 387

08-30-05 – – – – – 517

08-30-05 – – – – – 1,280

08-30-05 – – – – – 1,020

08-30-05 – – – – – 580

08-31-05 – <0.04 1.03 0.077 0.440 –

08-31-05 – – – – – 365

08-31-05 – – – – – 293

09-15-05 17 <0.04 1.87 0.037 0.075 5

10-25-05 10 <0.04 1.63 0.036 0.073 3

12-06-05 15 <0.04 1.65 E0.026 0.068 2

01-11-06 – – – – – 408

01-11-06 – – – – – 203

01-17-06 – – – – – 325

01-17-06 – – – – – 572

01-17-06 – – – – – 877

01-18-06 – – – – – 521

01-23-06 – – – – – 822

01-23-06 – – – – – 1,090

01-23-06 – – – – – 1,050

01-23-06 – – – – – 636

01-23-06 – – – – – 483

01-23-06 – – – – – 359

04-17-06 368 0.11 1.54 0.11 0.260 205

05-11-06 194 – – – – 294

05-26-06 – – – – – 1,160

05-26-06 – – – – – 1,140

05-26-06 – – – – – 728

05-26-06 5,660 0.024 0.73 0.074 0.460 761

05-26-06 – – – – – 514

05-26-06 – – – – – 413

05-26-06 – – – – – 331

06-21-06 97 E0.009 2.26 0.053 0.105 25

Big Spring – F15CS004 374755086090401 04-22-04 46 0.14 2.01 0.052 0.119 62

05-25-04 – <0.04 3.09 0.136 0.300 82

05-27-04 – <0.04 1.24 0.152 0.340 153

08-02-04 2.4 <0.04 2.32 0.037 0.052 6

09-07-04 1.6 <0.04 1.68 0.03 – 2

Appendix 1. Station Name, Sample-Collection Date, Nutrient, and Suspended 

Sediment Results for Samples Collected in the Karst Terrane of the Sinking 

Creek Basin, Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; mg-L, milligrams per liter; E, estimated, <, less than; –, no data]
Appendix 1 43

USGS station name USGS station No.

Samplecollection 

date

Discharge 

(ft3/s)

Ammonia

as N

(mg/L)

Nitrite plus 

nitrate as N 

(mg/L)

Orthophosphate as P 

(mg/L)

Total 

phosphorus 

(mg/L)

Suspended 

sediment 

(mg/L)

Big Spring – F15CS004–

Cont.

374755086090401 10-25-04 1.1 <0.04 1.87 0.031 0.042 1

11-22-04 7.5 <0.04 3.95 0.037 0.053 7

03-28-05 – 0.04 1.25 0.122 0.340 194

04-29-05 6.8 <0.04 2.3 0.017 0.029 7

05-20-05 – 0.61 4.95 0.459 0.830 440

07-13-05 2.5 <0.04 2.87 0.024 0.072 6

08-30-05 – E0.03 2.11 0.219 0.360 239

09-15-05 1.5 <0.04 2.32 0.033 0.053 2

10-25-05 0.9 <0.04 1.72 0.02 0.038 1

12-06-05 3.0 <0.04 2.96 0.035 0.062 2

04-17-06 5.9 <0.04 2.52 0.009 0.028 3

05-11-06 9.1 <0.04 3.47 0.022 0.040 4

05-26-06 – 0.057 1.12 0.261 0.450 281

06-21-06 6 E0.009 3.96 0.079 0.130 18

Flat Rock Spring – 

F14DS005

374813086171501 04-22-04 50 <0.04 1.61 0.03 0.077 25

05-25-04 – <0.04 0.76 0.115 0.300 138

07-08-04 12 <0.04 2.03 0.043 0.079 28

08-02-04 8.6 <0.04 1.9 0.092 0.148 20

09-07-04 4.8 <0.04 1.57 0.066 0.094 5

10-25-04 3.1 <0.04 1.57 0.045 0.057 3

11-22-04 23 <0.04 2.54 0.05 0.093 15

03-28-05 – 0.07 0.84 0.057 0.450 547

04-29-05 16 <0.04 1.99 0.022 0.040 6

05-20-05 – 0.11 1.38 0.134 0.610 788

07-13-05 16 <0.04 2.19 0.181 0.350 81

08-18-05 3.7 <0.04 2.31 0.043 0.057 25

08-30-05 – <0.04 1.73 0.164 0.300 246

09-15-05 4.5 <0.04 2.35 0.05 0.080 4

10-25-05 2.1 <0.04 1.97 0.027 0.057 1

12-06-05 3.5 <0.04 1.89 0.064 0.105 12

04-17-06 19 <0.04 1.68 0.023 0.037 10

05-11-06 20 <0.04 2.57 0.028 0.049 5

06-21-06 21 0.018 1.87 0.091 0.168 38

Ross Karst Window – 

F14DS003

374846086154101 05-25-04 – <0.04 0.82 0.092 0.240 106

05-27-04 – <0.04 0.42 0.043 0.410 581

08-02-04 – <0.04 1.95 0.081 0.140 25

09-07-04 – <0.04 1.59 0.06 0.089 6

10-25-04 – <0.04 1.47 0.041 0.060 6

Appendix 1. Station Name, Sample-Collection Date, Nutrient, and Suspended 

Sediment Results for Samples Collected in the Karst Terrane of the Sinking 

Creek Basin, Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; mg-L, milligrams per liter; E, estimated, <, less than; –, no data]
44 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

USGS station name USGS station No.

Samplecollection 

date

Discharge 

(ft3/s)

Ammonia

as N

(mg/L)

Nitrite plus 

nitrate as N 

(mg/L)

Orthophosphate as P 

(mg/L)

Total 

phosphorus 

(mg/L)

Suspended 

sediment 

(mg/L)

Ross Karst Window – 

F14DS003—Cont.

374846086154101 11-22-04 – <0.04 2.4 0.045 0.077 14

03-28-05 – 0.07 0.76 0.054 0.330 489

04-29-05 – <0.04 1.96 0.019 0.031 12

05-20-05 – 0.1 1.54 0.185 0.530 489

07-13-05 – <0.04 1.83 0.171 0.320 –

08-30-05 – E0.03 1.67 0.214 0.89 238

09-15-05 – <0.04 2.45 0.044 0.077 17

10-25-05 – <0.04 1.75 0.028 0.055 7

12-06-05 – <0.04 2.06 0.06 0.103 5

Fiddle Spring – F14DS007 374847086172901 04-22-04 23 <0.04 1.12 0.025 0.065 11

05-25-04 – <0.04 0.4 0.09 0.310 253

08-02-04 4.4 <0.04 2.08 0.192 0.250 28

09-07-04 2.7 <0.04 1.44 0.042 0.070 6

10-25-04 1.4 <0.04 1.13 0.038 0.055 6

11-22-04 7.4 <0.04 2.08 0.051 0.080 18

03-28-05 – 0.09 0.91 0.07 0.470 572

04-29-05 6.6 <0.04 1.69 0.022 0.037 9

05-20-05 364 0.1 1.32 0.14 0.620 731

07-13-05 8.7 E0.03 1.64 0.145 0.350 99

08-30-05 – E0.02 1.65 0.101 0.210 319

09-15-05 1.5 <0.04 1.57 0.025 0.057 4

10-25-05 1.2 <0.04 1.18 0.014 0.036 3

12-06-05 1.2 <0.04 1.65 0.079 0.141 8

04-17-06 12.0 <0.04 1.49 0.026 0.047 18

06-21-06 4.4 0.022 1.88 0.184 0.300 39

Boiling Spring – F14CS002 375209086224001 04-22-04 – <0.04 1.31 0.019 0.106 135

05-25-04 – <0.04 0.83 0.075 0.450 409

05-27-04 – <0.04 0.47 0.038 0.310 408

08-02-04 37 <0.04 2.23 0.078 0.106 11

09-07-04 3.5 <0.04 1.52 0.057 0.087 7

10-25-04 16 <0.04 1.26 0.041 0.072 7

11-22-04 153 <0.04 2.24 0.066 0.139 31

04-29-05 78 <0.04 1.67 0.022 0.037 8

05-20-05 – 0.07 1.39 0.093 0.580 1,040

07-13-05 – <0.04 1.81 0.086 0.230 81

10-25-05 10 <0.04 1.67 0.036 0.079 2

12-06-05 15 <0.04 1.75 0.043 0.075 3

Appendix 1. Station Name, Sample-Collection Date, Nutrient, and Suspended 

Sediment Results for Samples Collected in the Karst Terrane of the Sinking 

Creek Basin, Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; mg-L, milligrams per liter; E, estimated, <, less than; –, no data]
Appendix 2 45

Appendix 2. Station Name, Sample-Collection Date, and Select Pesticide 

Results for Samples Collected in the Karst Terrane of the Sinking Creek Basin, 

Kentucky, 2004–06

[ft3/s, cubic feet per second; μg/L, micrograms per liter; E, estimated; <, less than; –, no data]

USGS station name USGS station No.

Samplecollection 

date

Discharge

(ft3/s)

2-Chloro-4-

isopropylamino-6-

amino-striazine (DEA) 

(μg/L)

 Acetochlor

(μg/L)

Atrazine 

(μg/L)

Carbaryl 

(μg/L)

Malathion

(μg/L)

Metolachlor 

(μg/L)

Simazine

(μg/L)

Sinking Creek at 

Rosetta, Ky

03303195 04-22-04 125 E0.025 0.027 0.139 <0.041 <0.027 E0.010 0.013

05-27-04 2,080 E0.099 0.092 0.905 <0.041 <0.027 0.112 0.010

07-08-04 7.4 E0.063 0.008 0.436 <0.041 <0.027 0.025 0.009

08-02-04 7.0 E0.064 0.006 0.132 <0.041 <0.027 0.014 <0.010

09-07-04 17 E0.022 E0.003 0.044 <0.041 <0.027 E0.004 E0.005

10-25-04 – E0.015 <0.006 0.027 <0.041 <0.027 <0.006 <0.005

11-22-04 – E0.024 <0.010 0.024 <0.041 <0.027 <0.006 <0.005

03-16-05 29 E0.013 E0.005 0.009 <0.041 <0.027 <0.006 <0.005

03-28-05 1,000 E0.005 0.007 <0.007 <0.041 <0.027 E0.004 <0.005

04-12-05 35 E0.016 <0.006 0.013 <0.041 <0.027 <0.006 <0.005

04-29-05 17 E0.023 E0.004 0.025 <0.041 <0.027 E0.005 <0.005

05-17-05 15 E0.283 0.031 E24.6 E0.003 <0.027 0.202 0.093

05-20-05 428 E0.382 0.827 9.12 E0.079 <0.027 0.146 0.789

06-14-05 8.7 E0.042 0.008 0.550 <0.041 <0.027 0.008 0.045

07-13-05 14 E0.084 0.017 0.273 <0.041 <0.027 0.006 0.123

08-18-05 3.9 E0.033 <0.006 0.076 <0.041 <0.027 <0.006 0.014

08-30-05 1,250 E0.034 0.011 0.074 <0.041 <0.027 <0.006 <0.005

09-15-05 6.1 E0.037 <0.006 0.034 <0.041 <0.027 <0.006 <0.005

10-25-05 2.5 E0.024 <0.006 0.030 <0.041 <0.027 <0.006 0.008

12-06-05 4.7 E0.019 <0.006 0.025 <0.041 <0.027 <0.006 0.006

04-17-06 22 E0.011 <0.006 0.012 <0.041 <0.027 <0.006 0.012

05-11-06 36 – – – – – – –

05-26-06 2,140 E0.043 0.022 0.263 E.025 <0.027 0.046 0.033

06-21-06 14 E0.046 <0.006 1.57 <.041 <0.027 E0.005 0.053

Sinking Creek near 

Lodiburg, Ky

03303205 04-22-04 333 E0.047 0.010 0.409 <.041 <0.027 E0.008 0.017

05-25-04 1,160 E0.126 0.227 0.753 <.041 <0.027 0.047 0.035

05-27-04 5,260 E0.116 0.091 0.942 <.041 <0.027 0.102 0.056

07-08-04 44 E0.118 E0.006 0.200 <.041 <0.027 E0.011 0.014

07-12-04 – – – – – – – –

07-12-04 – – – – – – – –

08-02-04 38 E0.075 0.008 0.119 <.041 <0.027 E0.010 0.012

09-07-04 20 E0.046 E0.004 0.069 <.041 <0.027 E0.007 0.009

10-25-04 16 E0.035 <0.006 0.042 <.041 <0.027 0.009 <0.010

11-22-04 – E0.077 <0.006 0.037 <.041 <0.027 0.006 <0.005

03-16-05 110 E0.041 <0.006 0.017 <.041 <0.027 <0.006 <0.005

03-28-05 4,240 E0.012 E0.006 0.080 <.041 <0.027 0.008 <0.005

04-12-05 184 E0.050 <0.006 0.032 <.041 <0.027 E0.004 <0.005

04-29-05 79 E0.070 0.010 0.092 <.041 <0.027 0.006 0.009

05-17-05 59 E0.082 0.048 0.772 <.041 <0.027 0.018 0.028

05-19-05 – – – – – – – –

05-20-05 – E0.372 0.755 3.77 E0.059 <0.027 0.393 0.037

05-20-05 – – – – – – – –

05-20-05 – E0.442 1.07 4.65 E0.052 <0.027 .875 0.058
46 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

Appendix 2. Station Name, Sample-Collection Date, and Select Pesticide 

Results for Samples Collected in the Karst Terrane of the Sinking Creek Basin, 

Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; μg/L, micrograms per liter; E, estimated; <, less than; –, no data]

USGS station name USGS station No.

Samplecollection 

date

Discharge

(ft3/s)

2-Chloro-4-

isopropylamino-6-

amino-striazine (DEA) 

(μg/L)

 Acetochlor

(μg/L)

Atrazine 

(μg/L)

Carbaryl 

(μg/L)

Malathion

(μg/L)

Metolachlor 

(μg/L)

Simazine

(μg/L)

Sinking Creek near 

Lodiburg, Ky—

Cont.

03303205 05-20-05 – – – – – – – –

05-20-05 2,360 E0.324 .807 4.24 E.041 E.008 .466 .051

05-20-05 – – – – – – – –

05-20-05 – – – – – – – –

05-20-05 – E0.342 0.543 30.84 E0.043 <0.027 0.388 0.509

05-21-05 – – – – – – – –

05-21-05 – – – – – – – –

06-14-05 41 E0.118 <0.007 0.397 <0.041 <0.027 0.009 0.051

07-13-05 136 E0.100 0.071 0.262 E0.036 <0.027 0.034 0.033

08-18-05 17 E0.065 <0.006 0.077 <0.041 <0.027 <0.006 0.012

08-30-05 897 E0.035 0.017 0.061 <0.041 <0.027 0.012 <0.005

08-30-05 – – – – – – – –

08-30-05 – – – – – – – –

08-30-05 – – – – – – – –

08-30-05 – – – – – – – –

08-31-05 – – – – – – – –

08-31-05 – – – – – – – –

08-31-05 – – – – – – – –

09-15-05 17 E0.087 <0.006 0.059 <0.041 <0.027 0.009 0.013

10-25-05 10 E0.064 <0.006 0.043 <0.041 <0.027 E0.004 0.009

12-06-05 15 E0.034 <0.006 0.030 <0.041 <0.027 E0.005 0.006

01-11-06 – – – – – – – –

01-11-06 – – – – – – – –

01-17-06 – – – – – – – –

01-17-06 – – – – – – – –

01-17-06 – – – – – – – –

01-18-06 – – – – – – – –

01-23-06 – – – – – – – –

01-23-06 – – – – – – – –

01-23-06 – – – – – – – –

01-23-06 – – – – – – – –

01-23-06 – – – – – – – –

01-23-06 – – – – – – – –

04-17-06 368 E0.062 1.13 16.9 <0.041 <0.027 0.292 0.072

05-11-06 194 – – – – – – –

05-26-06 – – – – – – – –

05-26-06 – – – – – – – –

05-26-06 – – – – – – – –

05-26-06 5,660 E0.204 0.330 1.31 E0.039 <0.027 0.311 0.161

05-26-06 – – – – – – – –

05-26-06 – – – – – – – –

05-26-06 – – – – – – – –

06-21-06 97 E0.126 0.043 0.528 <0.041 <0.027 0.05 0.022
Appendix 2 47

USGS station name USGS station No.

Samplecollection 

date

Discharge

(ft3/s)

2-Chloro-4-

isopropylamino-6-

amino-striazine (DEA) 

(μg/L)

 Acetochlor

(μg/L)

Atrazine 

(μg/L)

Carbaryl 

(μg/L)

Malathion

(μg/L)

Metolachlor 

(μg/L)

Simazine

(μg/L)

Big Spring – 

F15CS004

374755086090401 04-22-04 46 E0.172 <0.010 4.92 <0.041 <0.027 0.309 0.152

05-25-04 – E0.300 0.014 2.08 <0.041 <0.027 0.447 0.043

05-27-04 – E0.330 0.009 2.99 <0.041 <0.027 0.736 0.548

08-02-04 2.4 E0.133 0.018 0.097 <0.041 <0.027 0.017 0.018

09-07-04 1.6 E0.093 0.007 0.065 <0.041 <0.027 E0.006 0.010

10-25-04 1.1 E0.042 0.010 0.034 <0.041 <0.027 <0.006 0.010

11-22-04 7.5 E0.289 <0.006 0.118 <0.041 <0.027 <0.006 <0.010

03-28-05 – E0.038 <0.006 0.030 <0.041 <0.027 E0.003 <0.005

04-29-05 6.8 E0.121 E0.006 0.212 <0.041 <0.027 0.017 0.100

05-20-05 – E1.11 2.85 11.5 <0.041 <0.027 1.55 2.68

07-13-05 2.5 E0.135 0.044 0.106 <0.041 <0.027 0.035 0.031

08-30-05 – E0.082 <0.020 0.090 <0.041 <0.027 0.193 0.013

09-15-05 1.5 E0.142 E0.003 0.058 <0.041 <0.027 <0.006 0.029

10-25-05 0.9 E0.058 <0.006 0.027 <0.041 <0.027 <0.006 0.011

12-06-05 3.0 E0.143 0.008 0.053 <0.041 <0.027 E0.004 0.009

04-17-06 5.9 E0.096 <0.006 0.035 <0.041 <0.027 <0.006 0.006

05-11-06 9.1 E0.289 0.030 1.02 <0.041 <0.027 0.026 0.100

05-26-06 – E0.250 0.520 1.05 E0.021 <0.027 0.272 0.141

06-21-06 5.7 E0.293 0.056 0.352 <0.041 <0.027 0.037 0.022

Flat Rock Spring – 

F14DS005

374813086171501 04-22-04 50 E0.062 0.011 0.588 <0.041 <0.027 E0.009 0.027

05-25-04 – E0.342 0.033 2.91 E0.009 <0.027 0.058 2.28

07-08-04 12 E0.138 E0.004 0.195 <0.041 <0.027 E0.010 0.020

08-02-04 9 E0.066 0.007 0.103 <0.041 0.181 E0.007 0.014

09-07-04 4.8 E0.075 <0.006 0.063 <0.041 <0.027 <0.013 0.019

10-25-04 3.1 E0.044 <0.006 0.046 <0.041 <0.027 <0.006 <0.010

11-22-04 23 E0.106 <0.006 0.059 <0.041 <0.027 <0.006 <0.005

03-28-05 – E0.009 <0.006 0.010 <0.041 <0.027 <0.006 <0.005

04-29-05 16 E0.072 E0.005 0.069 <0.041 <0.027 E0.002 0.020

05-20-05 – E0.244 0.577 2.67 E0.031 <0.027 0.068 0.665

07-13-05 16 E0.042 <0.006 0.121 <0.041 <0.027 0.021 0.128

08-18-05 3.7 E0.074 <0.006 0.050 <0.041 <0.027 <0.006 0.015

08-30-05 – E0.043 <0.006 0.052 <0.041 <0.027 0.038 0.014

09-15-05 4.5 E0.107 <0.006 0.056 <0.041 <0.027 <0.008 0.029

10-25-05 2.1 E0.060 <0.006 0.032 <0.041 <0.027 <0.006 0.012

12-06-05 3.5 E0.048 <0.006 0.029 <0.041 <0.027 <0.006 0.008

04-17-06 19 E0.052 <0.006 0.024 <0.041 <0.027 <0.006 E0.004

05-11-06 20 E0.143 0.027 0.858 <0.041 <0.027 0.017 0.041

06-21-06 21 E0.114 0.046 0.138 E0.011 <0.027 0.014 0.011

Appendix 2. Station Name, Sample-Collection Date, and Select Pesticide 

Results for Samples Collected in the Karst Terrane of the Sinking Creek Basin, 

Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; μg/L, micrograms per liter; E, estimated; <, less than; –, no data]
48 Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06

USGS station name USGS station No.

Samplecollection 

date

Discharge

(ft3/s)

2-Chloro-4-

isopropylamino-6-

amino-striazine (DEA) 

(μg/L)

 Acetochlor

(μg/L)

Atrazine 

(μg/L)

Carbaryl 

(μg/L)

Malathion

(μg/L)

Metolachlor 

(μg/L)

Simazine

(μg/L)

Ross Karst Window 

– F14DS003

374846086154101 05-25-04 – E0.252 0.080 2.10 E0.018 <0.027 0.048 1.31

05-27-04 – E0.133 0.016 1.45 <0.041 <0.027 0.345 0.507

08-02-04 – E0.083 0.008 0.109 <0.041 0.211 E0.009 0.019

09-07-04 – E0.070 E0.003 0.080 <0.041 <0.027 E0.005 0.012

10-25-04 – E0.042 <0.006 0.041 <0.041 <0.027 <0.010 0.015

11-22-04 – E0.107 <0.006 0.057 <0.041 <0.027 <0.006 <0.005

03-28-05 – E0.008 <0.006 0.011 <0.041 <0.027 <0.006 <0.005

04-29-05 – E0.072 E0.005 0.069 <0.041 <0.027 E0.002 0.016

05-20-05 – E0.198 0.806 2.18 E0.039 <0.027 0.288 0.448

07-13-05 – E0.048 0.007 0.111 <0.041 <0.027 0.032 0.127

08-30-05 – E0.033 <0.006 0.030 <0.041 <0.027 0.021 0.008

09-15-05 – E0.094 <0.006 0.052 <0.041 <0.027 0.006 0.021

10-25-05 – E0.058 <0.006 0.034 <0.041 <0.027 <0.006 0.011

12-06-05 – E0.062 <0.006 0.037 <0.041 <0.027 0.006 0.008

Fiddle Spring – 374847086172901 04-22-04 23 E0.031 <0.008 0.345 <0.041 <0.027 <0.013 0.013

 F14DS007 05-25-04 – E0.141 0.091 0.850 E0.012 <0.027 0.036 0.481

08-02-04 4.4 E0.026 0.011 0.075 E0.018 <0.027 <0.013 <0.005

09-07-04 2.7 E0.020 <0.006 0.047 <0.041 <0.027 <0.013 <0.005

10-25-04 1.4 E0.006 <0.006 0.013 <0.041 <0.027 <0.006 <0.005

11-22-04 7.4 E0.019 <0.006 0.026 <0.041 <0.027 <0.006 <0.005

03-28-05 – <0.010 <0.006 <0.010 <0.041 <0.027 <0.006 <0.005

04-29-05 6.6 E0.014 <0.006 0.009 <0.041 <0.027 <0.006 <0.005

05-20-05 364 E0.375 0.438 2.04 E0.093 <0.027 0.065 0.488

07-13-05 8.7 E0.010 <0.006 0.026 E0.022 <0.027 E0.003 <0.005

08-30-05 – E0.024 <0.006 0.028 <0.041 <0.027 0.025 <0.008

09-15-05 1.5 E0.015 <0.006 0.012 <0.041 <0.027 <0.006 <0.005

10-25-05 1.2 E0.009 <0.006 E0.006 <0.041 <0.027 <0.006 <0.005

12-06-05 1.2 E0.006 <0.006 0.01 <0.041 <0.027 <0.006 <0.005

04-17-06 12 E0.008 <0.006 E0.005 <0.041 <0.027 <0.006 <0.005

06-21-06 4.4 E0.018 <0.006 0.034 <0.041 <0.027 E0.005 <0.005

Boiling Spring – 375209086224001 04-22-04 – E0.047 0.010 0.424 <0.041 <0.027 E0.008 0.018

 F14CS002 05-25-04 – E0.104 0.137 0.658 <0.041 <0.027 0.042 0.039

05-27-04 – E0.109 0.082 0.866 <0.041 <0.027 0.106 0.050

08-02-04 37 E0.075 0.007 0.129 <0.041 <0.027 E0.011 0.013

09-07-04 3.5 E0.046 E0.004 0.073 <0.041 <0.027 E0.007 0.010

10-25-04 16 E0.035 <0.010 0.04 <0.041 <0.027 0.011 <0.010

11-22-04 153 E0.074 <0.006 0.042 <0.041 <0.027 0.008 <0.005

04-29-05 78 E0.063 0.014 0.105 <0.041 <0.027 0.007 0.010

05-20-05 – E0.398 0.652 40.35 E0.021 <0.027 0.365 0.076

07-13-05 – E0.073 0.076 0.269 E0.045 <0.027 0.033 0.030

10-25-05 10 E0.042 <0.006 0.031 <0.041 <0.027 E0.003 <0.007

12-06-05 15 – – – – – – –

Appendix 2. Station Name, Sample-Collection Date, and Select Pesticide 

Results for Samples Collected in the Karst Terrane of the Sinking Creek Basin, 

Kentucky, 2004–06—Continued

[ft3/s, cubic feet per second; μg/L, micrograms per liter; E, estimated; <, less than; –, no data]
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For more information concerning the research in this report, contact the

 Director, Kentucky Water Science Center

U.S. Geological Survey

9818 Bluegrass Parkway

Louisville, Kentucy 40299-1906

http://ky.water.usgs.gov
Crain— Nutrients, Select Pesticides, Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004–06—Scientific Investigations Report 2010–5167