Water Quality in the Santee River Basin and Coastal Drainages, North and South Carolina, 1995–98

Water Quality in the Santee River Basin and Coastal Drainages North and South Carolina, 1995–98

U.S. Department of the Interior Circular 1206 U.S. Geological Survey POINTS OF CONTACT AND ADDITIONAL INFORMATION

The companion Web site for NAWQA Study Unit summary reports: http://water.usgs.gov/nawqa/

Santee River Basin and coastal drainages contact and Web site: USGS State Representative U.S. Geological Survey Water Resources Division Stephenson Center, Suite 129 720 Gracern Road Columbia, SC 29210-7651 e-mail: [email protected] http://sc.water.usgs.gov/nawqa/santhome.html

National NAWQA Program: Chief, NAWQA Program U.S. Geological Survey Water Resources Division 12201 Sunrise Valley Drive, M.S. 413 Reston, VA 20192 http://water.usgs.gov/nawqa/

Other NAWQA summary reports

River Basin Assessments Red River of the North Basin (Circular 1169) Albemarle-Pamlico Drainage Basin (Circular 1157) Rio Grande Valley (Circular 1162) Allegheny and Monongahela River Basins (Circular 1202) Sacramento River Basin (Circular 1215) Apalachicola-Chattahoochee-Flint River Basin (Circular 1164) San Joaquin-Tulare Basins (Circular 1159) Central Arizona Basins (Circular 1213) South-Central Texas (Circular 1212) Central Columbia Plateau (Circular 1144) South Platte River Basin (Circular 1167) Central Nebraska Basins (Circular 1163) Southern Florida (Circular 1207) Connecticut, Housatonic and Thames River Basins (Circular 1155) Trinity River Basin (Circular 1171) Eastern Iowa Basins (Circular 1210) Upper Colorado River Basin (Circular 1214) Georgia-Florida Coastal Plain (Circular 1151) Upper Mississippi River Basin (Circular 1211) Hudson River Basin (Circular 1165) Upper Snake River Basin (Circular 1160) Kanawha-New River Basins (Circular 1204) Upper Tennessee River Basin (Circular 1205) Lake Erie-Lake Saint Clair Drainages (Circular 1203) Western Lake Michigan Drainages (Circular 1156) Las Vegas Valley Area and the Carson and Truckee River Basins White River Basin (Circular 1150) (Circular 1170) Willamette Basin (Circular 1161) Lower Illinois River Basin (Circular 1209) Long Island-New Jersey Coastal Drainages (Circular 1201) National Assessments Lower Susquehanna River Basin (Circular 1168) The Quality of Our Nation‘s Waters—Nutrients and Pesticides (Circular 1225) Mississippi Embayment (Circular 1208) Ozark Plateaus (Circular 1158) Potomac River Basin (Circular 1166) Puget Sound Basin (Circular 1216)

Front cover: Edisto River near Givhans, South Carolina. Back cover: Left—Surface-water sampling, Indian Creek, North Carolina; Middle—Fish identification, Jacob Fork River, North Carolina.

All photographs in this report were taken by members of the Santee River Basin and coastal drainages Study Unit, U.S. Geological Survey. Water Quality in the Santee River Basin and Coastal Drainages, North and South Carolina, 1995–98

By W. Brian Hughes, Thomas A. Abrahamsen, Terry L. Maluk, Eric J. Reuber, and Lance J. Wilhelm

U.S. GEOLOGICAL SURVEY CIRCULAR 1206

U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Government.

2000

Free on application to the U.S. Geological Survey Information Services Box 25286 Federal Center Denver, CO 80225

Or call: 1-888-ASK-USGS

Library of Congress Cataloging-in-Publications Data

Water-quality assessment of the Santee River Basin and coastal drainages, North and South Carolina, 1995–98 / by W. Brian Hughes…[et al.]. p. cm. -- (U.S. Geological Survey Circular ; 1206) Includes bibliographical references. ISBN 0-607-95422-1 (alk. paper) 1. Water quality--South Carolina--Santee River Watershed. 2. Water quality--North Carolina. I. Hughes, W. Brian. II. Geological Survey (U.S.) III. Series.

TD224.S6 W384 2000 363.739’42’097578--dc21 00-049461 CONTENTS

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM...... IV SUMMARY OF MAJOR FINDINGS ...... 1 Stream and River Highlights...... 1 Ground-Water Highlights ...... 2 INTRODUCTION TO THE SANTEE RIVER BASIN AND COASTAL DRAINAGES ...... 3 Physiography and Water Quality ...... 3 Land Use and Water Quality...... 3 Climate Conditions and Water Quality...... 4 Water Use...... 4 Flow Regulation, Impoundments, and Surface-Water Quality ...... 5 Aquifer Characteristics and Ground-Water Quality...... 5 MAJOR FINDINGS ...... 6 Pesticides Commonly Were Detected in Santee Basin Streams...... 6 Few Pesticides Were Detected in Drinking-Water Supply Aquifers ...... 7 Pesticides Were Common in Shallow Ground Water in Urban and Agricultural Areas...... 8 Organochlorine Pesticides Were Detected in Bed Sediment and Tissues ...... 8 NATIONAL PERSPECTIVE—Santee Basin Pesticide Findings Were Similar to National Findings...... 9 Phosphorus Concentrations in Streams Frequently Exceeded USEPA Goals ...... 10 Water-Supply Aquifers Rarely Exceeded Drinking-Water Standards for Nitrate...... 11 NATIONAL PERSPECTIVE—Phosphorus Concentrations in the Santee Basin Were in the Middle Range of National Results ...... 13 Bed Sediment Had Low Concentrations of Trace Elements ...... 14 NATIONAL PERSPECTIVE—Mercury Contamination Potential in Santee Basin Was Highest in Nation....14 Trace Elements Accumulated in Clam Tissue and Fish Livers ...... 15 Radon Exceeded Proposed Standards in Many Wells ...... 16 NATIONAL PERSPECTIVE—Radon Concentrations Were High in the Santee Basin ...... 16 Volatile Organic Compounds Were Common in Urban Ground Water ...... 17 Drinking-Water Aquifers Had Low Concentrations of Volatile Organic Compounds...... 18 Urban and Agricultural Streams Had High Concentrations of Bacteria ...... 19 Biological Communities Reflected Land-Use Differences ...... 20 NATIONAL PERSPECTIVE—Santee Basin Streams were in the Middle of National Biological Rankings..21 STUDY UNIT DESIGN...... 22 GLOSSARY ...... 24 REFERENCES...... 25 APPENDIX—WATER-QUALITY DATA FROM THE SANTEE RIVER BASIN AND COASTAL DRAINAGES IN A NATIONAL CONTEXT ...... 26

Contents III NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

THIS REPORT summarizes major findings about water quality in the Santee River Basin and coastal drainages that emerged from an assessment conducted between 1995 and 1998 by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Water quality is discussed in terms of local and regional issues and compared to conditions found in all 36 NAWQA study areas, called Study Units, assessed to date. Findings are also explained in the context of selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. The NAWQA program was not intended to assess the quality of the Nation’s drinking water, such as by monitoring water from household taps. Rather, the assessments focus on the quality of the resource itself, thereby complementing many ongoing Federal, State, and local drinking-water monitoring programs. The comparisons made in this report to drinking-water standards and guidelines are only in the context of the available untreated resource. Finally, this report includes information about the status of aquatic communities and the condition of in-stream habitats as elements of a complete water-quality assessment. Many topics covered in this report reflect the concerns of officials of State and Federal agencies, water-resource managers, and members of stakeholder groups who provided advice and input during the Santee River Basin and coastal drainages assessment. Basin residents who wish to know more about water quality in the areas where they live will find this report informative as well.

NAWQA Study Units— Assessment schedule 1991–95

1994–98

1997–2001

Not yet scheduled

High Plains Regional Ground Water Study, 1999-2004 Santee River Basin and coastal drainages

THE NAWQA PROGRAM seeks to improve scientific and public understanding of water quality in the Nation’s major river basins and ground-water systems. Better understanding facilitates effective resource management, accurate identification of water-quality priorities, and successful development of strategies that protect and restore water quality. Guided by a nationally consistent study design and shaped by ongoing communication with local, State, and Federal agencies, NAWQA assessments support the investigation of local issues and trends while providing a firm foundation for understanding water quality at regional and national scales. The ability to integrate local and national scales of data collection and analysis is a unique feature of the USGS NAWQA Program. The Santee River Basin and coastal drainages is one of 51 water-quality assessments initiated since 1991, when the U.S. Congress appopriated funds for the USGS to begin the NAWQA Program. As indicated on the map, 36 assessments have been completed, and 15 more assessments will conclude in 2001. Collectively, these assessments cover about one-half of the land area of the United States and include water resources that are available to more than 60 percent of the U.S. population.

IV National Water-Quality Assessment Program SUMMARY OF MAJOR FINDINGS

Stream and River Highlights 82° 81° EXPLANATION 36° Surface water sampled in the Santee River 36° WATER-QUALITY SAMPLING IN Basin and coastal drainages generally meets THE SANTEE RIVER BASIN Ca AND COASTAL DRAINAGES t

a w

e existing Federal and State guidelines for b g a STREAM-WATER SAMPLING SITE d R drinking-water quality and protection of i R North Carolina GROUND-WATER SAMPLING AREAS Charlotte aquatic life. However, urban and agricultural e South Carolina Piedmont aquifer 35° lu 35° B Sandhills aquifers land uses have affected water quality, as Piedmont Greenville- T yg Agricultural study and Floridan aquifer Spartanburg er indicated by elevated concentrations of E R no Columbia urban study ree bacteria, pesticides, and nutrients in basins R B Cow Castle Creek flow-path study r o a S d dominated by these land uses. al W uda R

R a

t 80°

e r

e 34° • The herbicides atrazine, simazine, and tebuthiu- 34° e NORTH 82° Columbia R CAROLINA ron were detected in almost every stream in the N . Fo Santee rk Basin Santee Basin, including those in forested areas, at S. Fo levels below aquatic-life and drinking-water rk S SOUTH

E a Cooper R n di t CAROLINA st ee guidelines. Four insecticides—malathion, diazi- o R R non, chlorpyrifos, and parathion—exceeded 33° Coastal 33° Plain aquatic-life guidelines. No pesticides exceeded Charleston drinking-water standards, though 7 of the 30 80° compounds detected do not have drinking-water standards and 13 do not have aquatic guidelines. 0 50 MILES 0 50 KILOMETERS Pesticide concentrations had seasonal patterns, 81° The Santee River Basin and coastal drainages (the “Santee Selected Indicators of Stream-Water Quality Basin”) is an approximately 24,000-square-mile area in North and Small Streams Major Rivers South Carolina that encompasses the Blue Ridge Mountains, the Agricul- Undeveloped/ Mixed Piedmont, and the Coastal Plain (Fenneman, 1946). Most of the Urban tural Forest Land Uses 3.5 million people in the Santee Basin live in urban areas. Eighty- 1 Pesticides six percent of the water used in homes and for industry is treated surface water withdrawn from rivers or reservoirs. Ground water is 2 Nutrients the main water source for rural households. Trace elements 3 ~ ~ with the highest concentrations measured in the spring fol- Organo- lowing application. 4 ~ chlorines • Nitrate concentrations did not exceed drinking-water Volatile standards in any streams sampled. Average total phosphorus 5 organics concentrations in four streams were above the U.S. Bacteria6 Environmental Protection Agency (USEPA) recommended goal to prevent nuisance aquatic growth. The South Fork Semivolatile 7 Catawba River had an average total phosphorus concentration organics ~ that was four times higher than the USEPA goal and is a Percentage of samples with concentrations equal to or greater than a significant source of phosphorus to downstream lakes. health-related national guideline for drinking water,aquatic life, or contact recreation; or above a national goal for preventing excess Wastewater discharge and agricultural runoff are major algal growth sources of nitrogen and phosphorus. Percentage of samples with concentrations less than a health-related national guideline for drinking water, aquatic life, or water-contact recreation; or below a national goal for preventing excess algal growth • Trace metals were detected frequently in bed sediment and Percentage of samples with no detection tissue, mostly at concentrations within aquatic-life guidelines. Not assessed Insufficient data Arsenic, chromium, and lead exceeded guidelines in a few 1 ~ Insecticides, herbicides, and pesticide metabolites, sampled in water. 2 samples. Although concentrations were not high in sediment Total phosphorus and nitrate (as nitrogen), sampled in water. 3 Arsenic, mercury, and metals, sampled in sediment. 4 samples, data suggest that mercury is accumulating in fish Organochlorine compounds including DDT and PCB's, sampled in sediment. 5 Solvents, refrigerants, fumigants, and gasoline compounds, sampled in water. and clams in concentrations that are harmful to humans or 6 Fecal coliform bacteria, sampled in water. animals that eat them. Sampling by State agencies has 7 Miscellaneous industrial chemicals and combustion by-products, sampled in sediment.

Summary of Major Findings 1

resulted in fish-consumption advisories for mercury in 49 rivers • Nitrate is the only nutrient that was detected in and reservoirs in South Carolina. significant concentrations in ground water, and it • Organochlorine pesticides were detected frequently in bed exceeded drinking-water standards in almost one-half sediment and tissue. Most of these compounds have been of the shallow monitoring wells in agricultural areas. discontinued for use for many years but continue to be detected Although this finding indicates significant because they are persistent in the environment. A derivative of contamination of shallow ground water, most DDT was detected at concentrations exceeding aquatic-life drinking-water wells are located in deeper aquifers. standards in sediment at three agricultural sites. Nitrate in the Piedmont and Sandhills aquifers was elevated above natural concentrations but exceeded • Volatile organic compounds (VOCs) known to occur in the aqui- standards in only two wells. The Floridan aquifer, fer adjacent to Gills Creek, an urban stream in Columbia, S.C., which is protected for the most part by confining units were frequently detected in the creek as well. Although no exist- in the study area, had relatively low concentrations of ing Federal or State drinking-water standards or aquatic guide- nitrate. lines were exceeded, this finding is consistent with the important influence of ground-water quality on stream-water • Radon, a naturally occurring radioactive gas, was quality. detected in almost all wells sampled in drinking-water aquifers. Over one-half of the wells had • Bacteria levels frequently exceeded South Carolina standards for concentrations that exceeded proposed Federal contact recreation in streams in forested, urban, and agricultural drinking-water standards. Most of the wells with areas. Standards were exceeded more frequently in small radon concentrations that exceeded the proposed streams than in large rivers. standard are located in the Piedmont aquifer. • Biological communities in urban and agricultural streams had • VOCs were detected in 27 of 30 monitoring wells in fewer species of fish and invertebrates that can tolerate contam- an urban setting. Most compounds were detected at ination than forested and mixed land-use streams. This suggests extremely low levels; however, the concentrations of that contaminants resulting from these land uses affect the natu- trichloroethylene, a solvent, and methyl tert-butyl ral communities that live in these areas, although factors such as ether, a gasoline additive, were above a drinking- habitat alteration can cause similar changes in biological com- water standard and an advisory level, respectively, in munities. one well each. Fifteen of the 35 compounds detected do not have drinking-water standards. VOCs in Ground-Water Highlights drinking-water supply aquifers were detected Ground water in the Santee Basin generally meets exist- throughout the Santee Basin, but no concentrations ing Federal and State standards for drinking water except exceeded drinking-water standards. with respect to nitrate, which failed to meet the drinking- Selected Indicators of Ground-Water Quality water standard in almost one-half of the shallow monitoring wells sampled in agricultural areas, and radon, which did Shallow Ground Water Water-Supply Aquifer not meet proposed standards in about one-half the drinking- Urban Agricultural Piedmont Sandhills Floridan water wells sampled basinwide. Pesticides were detected Pesticides1 frequently in urban, agricultural, and drinking-water supply wells, but only two samples exceeded drinking-water stan- Nitrate 2 dards. Many wells contained low concentrations of numer- 3 ous synthetic chemicals related to industry, household use, Radon and motor vehicles, and a few of these chemicals were at Volatile levels above drinking-water standards. organics 4 Percentage of samples with concentrations equal to or • Pesticides were detected in 17 of 90 wells sampled in drinking- greater than health-related national guidelines for drinking water water supply aquifers. Of the 34 detected, only 2 pesticides Percentage of samples with concentrations less than health-related national guidelines for drinking water exceeded drinking-water standards, but 11 of the detected Percentage of samples with no detection pesticides do not have standards. Most wells in agricultural and urban areas contained at least one pesticide, but only two wells Not assessed 1 Insecticides, herbicides, and pesticide metabolites, sampled in water. in urban areas had concentrations that exceeded drinking-water 2 Nitrate (as nitrogen), sampled in water. 3 standards. Radon, sampled in water. 4 Solvents, refrigerants, fumigants, and gasoline compounds, sampled in water.

2 Water Quality in the Santee River Basin and Coastal Drainages INTRODUCTION TO THE SANTEE RIVER BASIN AND COASTAL DRAINAGES The Santee River Basin and Most of the Coastal Plain is charac- Land Use and Water Quality coastal drainages includes about terized by slow-moving, low-gradi- The Santee Basin has a rapidly 24,000 square miles in North and ent streams that commonly are growing population of about 3.5 South Carolina. The Santee River bordered by extensive swamps million people. Most of the people has the second largest drainage (Smock and Gilinsky, 1992). The live in the urban areas of Charlotte, area in the Eastern United States, combination of slow-moving water N.C., and Greenville-Spartanburg, and its basin makes up 70 percent and large quantities of organic mat- Columbia, and Charleston, S.C. of the study area. The basins of the ter in the swamps results in a char- (fig. 1). The most common types of Cooper, Edisto, and numerous acteristically dark-colored water urban development are commercial smaller rivers make up the remain- called “blackwater.” Under natural and residential. der of the study area.Throughout conditions, blackwater streams As urban areas develop, this report, the study area, includ- have low pH and contain low con- increased use of pesticides and fer- ing these smaller river basins, will centrations of dissolved oxygen. tilizers on lawns and landscaped be collectively referred to as the These conditions can make the areas can lead to increased concen- “Santee Basin.” stream particularly susceptible to trations of these chemicals in water-quality degradation by the ground and surface waters. Com- Physiography and Water contribution of oxygen-consuming Quality mercial and residential use of sol- chemicals in wastewater discharge vents and fuel products can result The rugged mountains of the or nonpoint contamination. in their introduction to ground and Blue Ridge physiographic province are sparsely populated. Land-use effects on water quality are mini- mal because the area is largely undeveloped. Consequently, the

Blue Ridge has more pristine water EXPLANATION quality and intact stream ecosys- URBAN OR BUILT-UP tems than other parts of the study AGRICULTURAL CHARLOTTE area. North Carolina RANGELAND The rolling hills and abundant South Carolina FORESTED water resources of the Piedmont WATER GREENVILLE- WETLAND have attracted industrial develop- SPARTANBURG ment and human population STUDY UNIT BOUNDARY growth. Many of the areas experi- encing urban growth are in the Piedmont, near the headwaters of rivers that supply drinking water COLUMBIA and also receive treated waste water. Since flows in these head- water streams are smaller than they are farther along the stream courses, they have a limited capacity to assimilate large quantities of wastewater and nonpoint-source CHARLESTON inputs from the urban areas. The flat-lying topography and fertile soils of the Coastal Plain are 0 50 100 MILES ideal for agricultural use. Develop- 0 50 100 KILOMETERS ment for shipping, industry, and tourism is mostly limited to land Figure 1. Land use in the Santee Basin includes about 60 percent forested, 30 within a few miles of the coast. percent agricultural, and 6 percent urban lands.

Introduction to the Santee River Basin and Coastal Drainages 3

surface water through accidental increased flows also can help to spills or leaking storage tanks. Bac- dilute concentrations of chemicals 80 70 teria and nutrients can enter water in ground water and surface water. 60 through leaking sewer lines, mal- The distribution of rainfall in the 50 EXPLANATION functioning septic tanks, and from Santee Basin is fairly uniform 50 LINE OF EQUAL AVERAGE ANNUAL runoff of pet and waterfowl wastes. except for very high precipitation PRECIPITATION Although thoroughly regulated, in the Blue Ridge (South Carolina discharges from wastewater treat- Water Resources Commission, ment plants increase as population 1983; fig. 2). grows, increasing the loading of Seasonal variability of rainfall nutrients to streams. also is important. Generally the 50 Agriculture is an important eco- highest concentrations of pesticides nomic activity throughout the San- in streams occur when rainfall tee Basin. Row crop agriculture is immediately follows pesticide Figure 2. Precipitation affects water most common in the Coastal Plain, applications. Rainfall is highest in quality by producing runoff to streams where corn, soybeans, and cotton spring and summer, typically when and infiltration to aquifers. are the most common crops (South agricultural and residential lawn Carolina Agricultural Statistics pesticides are applied. Water Use Service, 1999). Pasture for hay and Rainfall also is important Most of the 7 billion gallons of for grazing cattle is typical of agri- because it contains nutrients and water used each day in the Santee cultural land in the Piedmont. metals that contribute to concentra- Basin is surface water (fig. 3). These agricultural activities can tions of these compounds in sur- About 85 percent of this water is result in elevated nutrient and pes- face water. Atmospheric deposition used in the production of electric- ticide levels in streams and ground accounts for the majority of ammo- ity, and the remainder is used for water from runoff or infiltration of nia and nitrate nitrogen in streams public water supplies, commercial manure, fertilizer, or pesticides. (Maluk and others, 1998). A study and industrial uses, irrigation of Most of the land in the Santee also has suggested that mercury crops, and watering livestock. Basin is forested. Forests range contamination in the Santee Basin Ground water accounts for only from largely unaltered hardwoods results from atmospheric deposi- about 14 percent of total water use in the Blue Ridge and mixed pine tion (Krabbenhoft and others, but is a very important resource. and hardwood stands in the Pied- 1999). Private domestic wells are the only mont to intensively managed pine plantations and forested wetlands in the Piedmont and Coastal Plain. EXPLANATION

Trees are commercially harvested DOMESTIC SUPPLY in all of these areas, producing var- THERMOELECTRIC ious levels of soil disturbance, ero- IRRIGATION AND LIVESTOCK sion, and increased sediment loads COMMERCIAL AND INDUSTRIAL in the streams. PUBLIC SUPPLY Climate Conditions and Water Quality The major climatic factors affecting water quality are seasonal and areal distributions of precipitation. The amount of rainfall affects (86 percent) (14 percent) water quality because areas with SURFACE-WATER USE IN 1995 GROUND-WATER USE IN 1995 higher rainfall generally have Figure 3. Most water used in the Santee Basin is supplied by surface water. Ground greater runoff and more infiltration water is important because it is the major source of domestic water supply in rural to ground water. However, areas. Relative size of pie charts represents relative percentage water use.

4 Water Quality in the Santee River Basin and Coastal Drainages viable sources of water in areas not nutrient enriched, and cause algal Sandy soils typically are present in served by public water supplies. blooms. Occasionally, fishkills parts of the Coastal Plain and to a result when the artificially large lesser degree in the Piedmont. Flow Regulation, Impound- algal population dies and the dis- Deep aquifers also can be ments, and Surface-Water solved oxygen, which is necessary susceptible to contamination, Quality for fish survival, is consumed dur- depending on their degree of The regulation of flow in the ing the decaying process. Of 11 connection to the surface. The Santee Basin has altered the histor- major lakes in the study area, 9 Piedmont, Sandhills, and Floridan ical seasonal flow patterns in the contained areas with “excessive aquifers supply most of the ground rivers. High peak flows and nutrients, extremely high produc- water in the Santee Basin (fig. 4). extreme low flows downstream tivity” and were “susceptible to Ground water in the Piedmont from major reservoirs generally are nuisance macrophyte growth and aquifer occurs in fractures or less common than they were prior algal blooms” (Stecker and cracks in the hard crystalline to construction of the reservoirs. Crocker, 1991). bedrock. In most areas, the bedrock The alteration of flow primarily is overlain by clay soils of variable affects the physical habitat of the Aquifer Characteristics and thickness. Sandhills aquifers are rivers and also can affect stream Ground-Water Quality unconfined; that is, they have no temperature. Populations of aquatic Shallow ground water (generally clay layer above them to inhibit the organisms are altered due to less than 50 feet below land downward movement of changed conditions in the streams surface) is vulnerable to contaminants to the aquifer. The downstream from reservoirs. For contamination in much of the Floridan aquifer is confined toward example, cold water discharged Santee Basin. Fertilizers, the coast but is unconfined farther from the bottom of Lake Murray pesticides, and spills or leaks of inland. Of the three aquifers, the makes it possible for trout to sur- chemicals at or near the land Sandhills aquifer is the most vive nearly 100 miles beyond their surface can move rapidly to the susceptible to contamination normal range. water table. Areas with sandy soils because of its sandy soils and lack Reservoirs are especially are particularly susceptible to of confinement. The Floridan affected by stream chemistry contamination because these aquifer, near the coast, is the least because they trap sediment and the coarse-grained soils allow rapid susceptible because it is confined. phosphorus that attaches to the sed- transport and provide little iment. This trapping process can opportunity for filtration or cause lakes to become eutrophic, or degradation of contaminants.

Sandhills aquifers Piedmont aquifer A' Surficial aquifer

Floridan aquifer Tertiary sand aquifer

Black Creek aquifer A North Carolina Line of section Middendorf aquifer

Study South Area Carolina EXPLANATION Cape Fear aquifer A' CONFINING UNIT

Not to scale

Figure 4. Aquifers sampled in the Santee Basin include the surficial, Piedmont, Sandhills, and Floridan aquifers (modified from Aucott and others, 1987). The Black Creek, Middendorf, and Cape Fear aquifers are not used much in the study area because of the cost of drilling deep wells and poor water quality.

Introduction to the Santee River Basin and Coastal Drainages 5 MAJOR FINDINGS

Pesticides Commonly Were Detected in Santee Basin Streams Thirty pesticides, including 22 herbicides and 8 insecticides, were detected in streams in the Santee Basin (Maluk and Kelley, 1998). Of the 161 surface-water samples collected, 141 contained at least one pesticide. At least one pesticide was detected at all of the sites, including forested sites that have little influence from humans. Insecticides were detected most frequently in urban streams, Although detections were fre- such as Gills Creek in Columbia, S.C. quent, concentrations tended to be low, with no herbicides and only Urban Streams Contain More Insecticides were detected about four insecticides and one metabo- Pesticides than Other Streams four times more frequently at urban lite exceeding aquatic-life criteria. Pesticides were detected more stream sites than at agricultural None of the pesticide concentra- frequently in urban streams than in stream sites, and aquatic-life crite- tions exceeded drinking-water agricultural streams (fig. 5). The ria were exceeded in nine samples standards. Thirteen of the 30 pesti- most commonly detected herbi- collected at urban sites and in three cides detected do not have aquatic cides—simazine, prometon, atra- samples collected at agricultural criteria and 7 do not have drinking- zine, and tebuthiuron—were sites. The insecticide diazinon was water standards (U.S. Environmen- detected nearly twice as frequently detected only in urban streams, tal Protection Agency, 1996). in water samples collected at urban whereas chlorpyrifos was detected Herbicides were the most com- sites than at agricultural sites. Con- frequently in both urban and agri- monly detected pesticides in versely, some herbicides such as cultural streams. This agrees with streams. Atrazine, an herbicide metolachlor and alachlor were national findings in which insecti- used on corn as well as turfgrasses detected almost exclusively at agri- cides were detected more fre- and golf courses, was detected at cultural sites. quently in urban than in the most sites, occurring at 11 of the 13 sampling sites. Other frequently detected herbicides were URBAN AGRICULTURAL 100 simazine, metolachlor, and prometon.Tebuthiuron, an herbicide that generally is used to control weeds 80 on highway and railroad rights-of- way, also was detected frequently. 60 EXPLANATION Insecticides were detected much INSECTICIDES less frequently than herbicides, 40 HERBICIDES accounting for less than one-third of the pesticides detected. Most 20 insecticides detected are used on agricultural and ornamental crops, WITH DETECTION OF SAMPLES PERCENTAGE 0 lawns, livestock, and in homes and

SIMAZINE ATRAZINE SIMAZINE ATRAZINE gardens. Those most commonly DIAZINONCARBARYL ALACHLOR DIAZINONCARBARYL ALACHLOR MALATHION PROMETON MALATHION PROMETON TEBUTHIURON TEBUTHIURON detected included chlorpyrifos, CHLORPYRIFOS METOLACHLOR CHLORPYRIFOS METOLACHLOR diazinon, malathion, and carbaryl. Figure 5. Pesticides, particularly insecticides, were detected more frequently in urban streams than in agricultural streams.

6 Water Quality in the Santee River Basin and Coastal Drainages

agricultural streams (U.S. Geologi- were observed during storms that cal Survey, 1999). followed applications. These findings indicate that Understanding these patterns of while agricultural activities con- occurrence is important because tribute pesticides to surface water, sampling programs need to be concentrations are rarely high designed so that critical periods of enough to affect aquatic life. The high pesticide concentrations are consequences of urban and subur- monitored. This information also ban use of pesticides is much more can be used by environmental man- significant, with concentrations of agers to assess risk associated with insecticides frequently at levels that agricultural chemical use. can affect aquatic life. Figure 6. Herbicide concentrations Few Pesticides Were generally peaked following spring Pesticides Showed Seasonal Detected in Drinking-Water applications in Gills Creek, an urban Patterns in Streams Supply Aquifers stream. Some herbicides showed pat- Of the 90 drinking-water, indus- the other aquifers, as is illustrated terns of occurrence that can be trial, and irrigation supply wells by the larger number of pesticides related to seasonal applications and sampled in the Floridan, Piedmont, detected and the higher detection weather patterns. At Gills Creek, and Sandhills aquifers, 17 had frequency in the Sandhills aquifers an urban stream, concentrations of detectable concentrations of pesti- than in the Piedmont and Floridan herbicides, such as atrazine, cides; of those, only two wells had aquifers (fig.7). In addition, the two simazine, and tebuthiuron, peaked pesticide concentrations that wells that had pesticide concentra- in the spring following application exceeded USEPA drinking-water tions exceeding USEPA drinking- and gradually decreased over the standards (U.S. Environmental Pro- water standards were located in the summer (fig. 6). Atrazine and tection Agency, 1996). Eleven of Sandhills aquifers. Drinking water simazine followed a similar pat- the 34 pesticides detected in drink- obtained from the Piedmont and tern at Cow Castle Creek, an agri- ing-water supply aquifers did not Floridan aquifers is probably cultural stream, with the addition have water-quality standards. unlikely to contain pesticides at of a second peak in early fall. The The Sandhills aquifers are more harmful levels; however, the high highest concentrations at all sites susceptible to contamination than rate of detection and large number of pesticides detected in the San- dhills aquifers are a cause for concern.

5 NONE DETECTED NUMBER OF PESTICIDES DETECTED 0 Floridan Piedmont Sandhills

AQUIFERS SAMPLED

Figure 7. The large number of pesti- Ground-water samples are pumped directly into a mobile laboratory for process- cides detected in the Sandhills aquifers ing samples and conducting field analyses. illustrates its relatively high susceptibility to contamination.

Major Findings 7 The differences in the rate and Pesticides were detected in number of detections in the aqui- ground water in urban areas about 60 fers may be related to differences twice as frequently as in agricul- 50 in aquifer properties. The Sandhills tural areas (fig. 8). Some pesticides are largely composed of layers of detected in urban and agricultural 40 coarse and fine sand with various ground water were the same, 30 quantities of clay. No continuous although insecticides were detected 20 confining unit or soil layer overlies more frequently in urban ground 10

PERCENTAGE OF SAMPLESWITH PERCENTAGE the aquifer to impede the move- water. This was similar to national PESTICIDE DETECTIONS ment of contaminants into ground NAWQA findings. The insecticide 0 URBAN AGRICULTURAL water. At the other extreme, the most frequently detected at urban Figure 8. Pesticides were detected Floridan aquifer has an overlying sites was dieldrin. Although its more frequently at urban ground-water clay confining layer that impedes agricultural use was canceled in the sites than at agricultural sites. vertical movement of contami- mid-1970s, dieldrin (and aldrin, nants throughout much of its extent which breaks down to dieldrin) was Organochlorine Pesticides (Aucott and others, 1987). The used for termite control until the Were Detected in Bed Piedmont aquifer has an overlying mid-1980s and is a persistent com- Sediment and Tissues layer of weathered bedrock that pound (Barbash and Resek, 1996). Fourteen pesticides were contains abundant clay. The thick- Dieldrin was also the most com- detected in streambed-sediment ness of this unit is highly variable, monly detected pesticide in urban samples, and 21 of 24 sites sam- but generally it impedes rapid verti- ground water nationally (U.S. Geo- pled had at least one detectable cal movement of contaminants logical Survey, 1999). pesticide. All of the pesticides from land surface to ground water. detected in sediment were organochlorine insecticides, such Pesticides Were Common in as chlordane, dieldrin, mirex, and Shallow Ground Water in DDT and its derivatives. Many of Urban and Agricultural Areas these compounds had their agricul- Pesticides were detected in 24 of tural uses cancelled more than 20 30 shallow wells in urban areas and years ago, yet they still appear in in 22 of 30 wells in agricultural sediment samples. The reason for areas (Reuber, 1999). Dieldrin con- this is because the compounds are centrations exceeded drinking- persistent, or are highly resistant to water standards in four urban chemical breakdown. wells; however, the wells sampled Of the compounds detected, only were installed for monitoring pur- DDE, a breakdown product of poses only and are not drinking- DDT, exceeded guidelines for the water supply wells. Dieldrin also protection of aquatic life. The exceeded aquatic-life standards in guidelines were exceeded at three these four urban wells, and tebuthi- sites, all of which are in basins with uron concentrations exceeded a high percentage of agricultural aquatic-life standards in one agri- land. In addition, DDT concentra- cultural well. Generally, ground- tions were only slightly below the water concentrations are not com- aquatic guidelines at several sites. pared to aquatic-life standards; Comparisons of land use to con- however, these concentrations can centrations of organochlorine pesti- be of concern because shallow cides generally did not show strong ground water can discharge to Shallow wells for the urban ground-water relations, primarily because these streams, elevating the pesticide study were installed by the U.S. Geologi- insecticides were used in both concentrations in surface water. cal Survey with assistance from the urban and agricultural settings South Carolina Geological Survey. (fig. 9). The only prominent rela-

8 Water Quality in the Santee River Basin and Coastal Drainages

35 SANTEE BASIN PESTICIDE FINDINGS 30 WERE SIMILAR TO NATIONAL FINDINGS 25

15 The most common pesticides detected in the Santee Basin included atrazine,

10 simazine, tebuthiuron, prometon, and metolachlor. These pesticides were among

5 the top 11 pesticides detected nationally. Consistent with national findings,

0 herbicides were the most common type of pesticide detected in streams and

Forested Urban Agricultural Mixed aquifers in agricultural areas in the Santee Basin, whereas insecticides were IN SEDIMENT, IN MICROGRAMS PER KILOGRAM PER MICROGRAMS IN SEDIMENT, IN TOTAL ORGANOCHLORINE PESTICIDE CONCENTRATION PESTICIDE ORGANOCHLORINE TOTAL LAND-USE SETTING IN STREAM BASINS more prevalent in urban areas. Overall, streams and aquifers that integrate Figure 9. Bed sediment in forested set- different land uses had lower concentrations of pesticides than those that are tings has significantly lower total orga- dominated by either agricultural or urban land uses. Detections of pesticides in nochlorine pesticide concentrations mixed land-use streams in the Santee Basin overall were much less frequent than bed sediment in other land-use than national detections. The most striking differences between national and settings. Santee Basin findings are the more frequent detections of alachlor, diazinon, and metolachlor in agricultural streams, simazine in agricultural and urban streams, tion is the uniformly low levels of and tebuthiuron in all land-use settings in the Santee Basin. The greater detection these pesticides detected at forested frequency does not appear to result from higher use of these compounds in the sites where these chemicals were Santee Basin. less likely to be used. 100 The same pesticides detected in AGRICULTURAL LAND USE sediments were also in clam and 80 INSECTICIDES HERBICIDES fish tissues. Concentrations measured were generally much higher 60 in tissue than in sediment; however, EXPLANATION 40 a direct comparison of these con- STREAMS centrations may not be valid 20 because of potential differences in NATIONAL exposure rates of sediment and 0 SANTEE BASIN 100 fish, differences in uptake by sedi- URBAN LAND USE ment organic carbon and tissue, 80 INSECTICIDES HERBICIDES GROUND WATER and partitioning in fish tissue. NATIONAL 60 SANTEE BASIN

0 100 MIXED LAND USE

DETECTION FREQUENCY, IN PERCENTDETECTION FREQUENCY, 80 INSECTICIDES HERBICIDES

Organochlorine pesticides, such as SIMAZINE DDT, can be found in streambed CARBARYL DIAZINON ATRAZINE ALACHLORCYANAZINE PROMETON sediment and can accumulate in TEBUTHIURON METOLACHLOR tissues of fish, such as this carp. CHLORPYRIFOS DEETHYLATRAZINE

Major Findings 9 Phosphorus Concentrations streams that do not directly dis- in Streams Frequently charge to reservoirs (U.S. Environ- Exceeded USEPA Goals mental Protection Agency, 1986). Nutrients measured in streams in The purpose of this goal is to pre- the Santee Basin, such as ammonia, vent excessive plant growth in nitrite, nitrate, phosphate, and streams. Indian Creek, N.C., Con- orthophosphate, were elevated garee River, and Brushy Creek do above background concentrations not meet this goal based on mean in areas affected by agricultural annual concentrations (fig. 10). and urban runoff. Of these nutri- Only two of the streams sampled The Congaree River is one of several ents, the only one governed by a did not have at least one sample rivers in the Santee Basin that exceed- above the goal. These were Jacob ed the U.S. Environmental Protection drinking-water standard is nitrite- Agency goal for phosphorus. plus-nitrate nitrogen (hereinafter Fork River and McTier Creek, both referred to as nitrate) because it is of which drain forested watersheds. Although 34 of the 90 sites showed the only nutrient that directly The remaining streams had per- decreasing trends in phosphorus affects human health. None of the centages of individual samples that concentrations, 53 showed no surface-water samples had concen- exceeded the goal, ranging from 4 trend, and 3 had increasing trends. trations of nitrate that were above to 96 percent. An analysis of nutrient data col- the drinking-water standard of Agricultural Runoff and Industrial 10 milligrams per liter (mg/L) lected by State monitoring agencies during 1973–93 (Maluk and others, Discharges are Sources of (U.S. Environmental Protection Nutrients in Surface Water Agency, 1996). 1998) showed that all but 3 of 90 Phosphorus concentrations were stream and lake sites exceeded the For all the streams in the study above the USEPA goal in several applicable phosphorus goal at least unit, except in the South Fork rivers in the Santee Basin. For once, and 23 sites had median con- Catawba River, there is a strong example, the flow-weighted mean centrations that exceeded the goal. relation between orthophosphate annual concentration of total phosphorus in the South Fork Catawba River is about four times higher 0.35 than the USEPA goal for streams entering a reservoir (U.S. Environ- 0.30 mental Protection Agency, 1986) (fig. 10). This is important because 0.25 many of the reservoirs in the San- U.S. Environmental Protection Agency Phosphorus Goal For Waters Entering tee Basin are eutrophic; that is, 0.20 Reservoirs they have high levels of nutrients that can result in excessive growth 0.15 U.S. Environmental Protection Agency Phosphorus Goal For Waters Not Entering of algae (Stecker and Crocker, Reservoirs 1991). Much of the phosphorus and 0.10 nitrogen that feeds the algae is carried into the reservoirs by major 0.05 rivers. The South Fork Catawba 0

FLOW-WEIGHTED MEAN CONCENTRATION OF TOTAL OF MEAN CONCENTRATION FLOW-WEIGHTED River flows into Lake Wylie IN MILLIGRAMS PER LITER PHOSPHORUS, directly downstream of the sam- Gills Creek, SC Indian Creek, NCBrushy Creek,Indian SCCreek,Saluda SC River, SC McTier Creek, SCEdisto River, SC pling site and is the only stream Congaree River, SC Jacob Fork River, NC Cow Castle Creek, SC sampled that enters directly into a Coosawhatchie River, SC South Fork Catawba River, NC reservoir. Figure 10. Three streams in the Santee Basin frequently exceeded the U.S. Environ- The USEPA also has a goal of mental Protection Agency goal for phosphorus in surface waters not entering reser- 0.1 mg/L total phosphorus for voirs, and one exceeded the goal for waters entering reservoirs.

10 Water Quality in the Santee River Basin and Coastal Drainages

(the predominant form of dissolved 0.08 centrations of nitrate than wells in phosphorus in streams) 0.07 SOUTH FORK agricultural lands and were lower CATAWBA RIVER concentrations and the percentage 0.06 than the national NAWQA median of agricultural land in the basins 0.05 for urban land use. 0.04 sampled (fig. 12). This relation 0.03 Nitrate concentrations measured most likely results from the runoff 0.02 in the three drinking-water supply of phosphate-containing chemical 0.01 aquifers sampled in the Santee 0

CONCENTRATION OF ORTHOPHOSPHATE, CONCENTRATION fertilizer and manure from IN MILLIGRAMS PER LITER 0 1020304050607080 Basin were variable. The Pied- agricultural lands. The relation PERCENTAGE OF AGRICULTURAL LAND IN STREAM BASIN mont had the highest nitrate con- generally is not influenced by Figure 11. The concentration of ortho- centrations, followed by the municipal waste-water discharges phosphate in streams is directly related Sandhills and Floridan aquifers because phosphate-containing to the percentage of agricultural land in the stream basin except for the South (fig. 13). Only two wells exceeded detergents have been banned for Fork Catawba River. the drinking-water standard for domestic use in the Santee Basin nitrate, one each in the Piedmont since the late 1990s (Litke, 1999). wells that exceeded the standard and Sandhills aquifers. With the The South Fork Catawba River were located in the shallow aquifer exception of these two wells, most has much higher concentrations of beneath agricultural land in the concentrations measured were well orthophosphate than would be pre- Coastal Plain. In fact, wells in the within the standard. One of the dicted from the amount of agricul- agricultural land-use study had the wells with a concentration above tural land in the basin (fig. 11). highest concentrations of nitrate the standard was an irrigation well This may result from a lack of a overall, with concentrations up to located in the middle of a corn and phosphorus ban on industrial users. 23 mg/L and a median concentra- soybean field; the other was adja- The South Fork Catawba River tion about double the national cent to a golf course. These results Basin contains a large concentra- NAWQA median for agricultural suggest that most wells in these tion of industries that use phos- land use (fig.12). Although the three aquifers are safe from high phate detergents, which are a shallow aquifer generally is not levels of nitrate, but some concern potential source for the high ortho- used for drinking-water supplies, is justified for wells located near phosphate levels in the South Fork the potential for movement of areas with high fertilizer use. Catawba River (Lindsey and nitrate-enriched water to deeper The higher nitrate concentrations Lewis, 1994). aquifers used for water supply is a in the Piedmont and Sandhills aqui- cause for concern. Wells beneath fers are related to the lack of con- Water-Supply Aquifers urban land had lower median con- Rarely Exceeded Drinking- Water Standards for Nitrate 6 With the exceptions of nitrate, most nutrient concentrations in 5 ground water in the Santee Basin SANTEE BASIN were low. This is fairly typical of 4 ground water in which most forms NATIONAL of nitrogen and phosphorus are 3 negligible (Nolan and Stoner, 2000). 2 Nitrate concentrations exceeded the USEPA (1996) drinking-water 1 standard of 10 mg/L in 14 of the 150 wells sampled. Drinking water 0

MEDIAN NITRATE CONCENTRATION IN CONCENTRATION MEDIAN NITRATE GROUND WATER, IN MILLIGRAMS PER LITER WATER, GROUND AGRICULTURAL URBAN LAND MAJOR containing concentrations of nitrate LAND USE USE AQUIFERS above the standard can result in methemoglobinemia, a life-threat- Figure 12. Nitrate concentrations in shallow ground water in agricultural areas were higher than those in urban areas and in ening illness. All but two of the major aquifers.

Major Findings 11 0.8 Nitrate in Ground Water Can Affect all locations where ground water 0.7 Nitrate Concentrations in Streams discharges to Cow Castle Creek. 0.6 Local conditions can strongly This is evidenced by the high con- 0.5 affect the nitrogen concentrations centrations of nitrate measured in 0.4 in ground water and how much Cow Castle Creek during low flow 0.3 nitrate discharges from ground when most streamflow is attributed 0.2 water to surface water. A study of to ground-water discharge. 0.1 the transport of nitrate in ground MEDIAN CONCENTRATION OF MEDIAN CONCENTRATION IN MILLIGRAMS PER LITER NITRATE, 0 water was conducted at an agricul-

NATIONAL tural site adjacent to Cow Castle FLORIDANSANDHILLS PIEDMONT MEDIAN AQUIFER AQUIFER AQUIFER Creek, S.C. (fig. 14). At this site, Figure 13. The Piedmont and Sandhills ground water beneath a corn field aquifers had higher median nitrate con- had concentrations of nitrate more centrations than the Floridan aquifer. than 28 mg/L, nearly three times finement for these aquifers, which the drinking-water standard. Along readily allows the downward the ground-water flow path, nitrate movement of surficial contami- concentrations decreased to less nants. Water in these aquifers often than 5 mg/L. has high dissolved oxygen concen- Directly below the streambed, trations, which prevents denitrifi- nitrate concentrations were above cation (the removal of nitrate by 4 mg/L. However, as ground water conversion to nitrogen gas). By moves upward to the stream, it comparison, the Floridan aquifer passes through an organic-rich has the lowest nitrate concentra- zone containing little dissolved oxygen. Denitrification occurring Water levels were measured simulta- tions because it is confined, mean- neously in Cow Castle Creek and at ing little water moves vertically in this zone results in water with a multiple depths in the aquifer below into the aquifer, and it has little dis- nitrate concentration of only the creek. Under most streamflow solved oxygen, a condition which 0.4 mg/L. conditions, water from the aquifer was moving upward into the creek. can promote denitrification. Denitrification may not always be effective in removing nitrate at

Corn field

Hay field 150 Pines 150 Unsaturated zone 140 14.1 140 Water table 5.1 Cow Castle 28.3 12.7 Creek 3.2 11.9 130 5.7 130 2.3 0.6 0.8 2.0 9.6 3.6 8.1 120 0.4 12.1 2.4 Sand and clay 3.1 120 4.5 2.2 3.7 2.0 surficial aquifer 1.8

ALTITUDE, IN FEET 110 4.7 110 Santee Limestone Datum is sea level Vertical scale is greatly exaggerated 100 100 0200 400 600 800 1,000 FEET EXPLANATION 0 100 200 300 METERS 12.4 WELL; NUMBERS INDICATE NITRATE CONCENTRATION LESS 3.8 NITRATE CONCENTRATIONS, THAN 10 MILLIGRAMS PER LITER 0.7 IN MILLIGRAMS PER LITER NITRATE CONCENTRATION GREATER THAN 10 MILLIGRAMS PER LITER DIRECTION OF GROUND- WATER FLOW

Figure 14. Concentrations of nitrate are reduced through denitrification as ground water flows to Cow Castle Creek. Typical wells used for water supply in this area are greater than 100 feet deep. Nitrate concentrations at that depth generally are not above drinking-water standards.

12 Water Quality in the Santee River Basin and Coastal Drainages

PHOSPHORUS CONCENTRATIONS IN THE SANTEE BASIN WERE IN THE MIDDLE RANGE OF NATIONAL RESULTS

Six of the 12 streams sampled in the Santee Basin had average concentrations of total phosphorus that Agricultural Areas were within the medium concentration range of all streams sampled in the NAWQA Program. The exceptions were an agricultural area drained by Indian Creek in North Carolina, which ranked high nationally, and two mixed land-use streams, which were in the lowest category for phosphorus. Nationally, higher concentrations of phosphorus corresponded to areas of the Midwest that also had high inputs of phosphorus from fertilizer and manure that were applied to agricultural lands. Phosphorus SANTEE BASIN inputs from agriculture in the Santee Basin were typically in the low to middle range. The two mixed land-use sites that had the lowest phosphorus concentrations compared to national results were Urban Areas located on the Saluda and Edisto Rivers. The Saluda River site is located downstream from a major reservoir that traps much of the phosphorus carried into the system. The Edisto River is located in the Coastal Plain and mostly drains forested and agricultural lands. Extensive wetlands border the Edisto River and may act as local traps for phosphorus attached to sediment.

SANTEE BASIN EXPLANATION

AVERAGE ANNUAL CONCENTRATION OF TOTAL PHOSPHORUS--IN MILLIGRAMS PER LITER Highest (greater than 0.27) Mixed Land-Use Areas Medium (0.05 to 0.27) Lowest (less than 0.05)

BACKGROUND CONCENTRATIONS Bold outline indicates median values greater than USEPA desired goal of 0.1 milligrams per liter for prevention of nuisance plant growth in flowing waters not discharging directly to lakes and impoundments AVERAGE ANNUAL TOTAL PHOSPHORUS INPUT-- IN POUNDS PER ACRE, BY COUNTY, FOR 1995-98. SANTEE BASIN INPUTS ARE FROM FERTILIZER AND MANURE Greater than 5 pounds per acre 2 to 5 pounds per acre Less than 2 pounds per acre

Major Findings 13 Bed Sediment Had Low Concentrations of Trace MERCURY CONTAMINATION POTENTIAL IN Elements SANTEE BASIN WAS HIGHEST IN NATION Trace elements in bed sediment were detected frequently but mostly at concentrations below Mercury is a widespread and extremely toxic contaminant that affects the Nation’s those expected to affect aquatic life aquatic ecosystems. Approximately 80 percent of the fish consumption advisories (Canadian Council of Ministers of in the Nation were issued as a result of contamination by mercury (U.S. Environ- mental Protection Agency, 1998). Methylmercury is the form of mercury that is the Environment, 1995). Arsenic easily accumulated in the tissues of organisms. As part of the NAWQA Program, a and lead exceeded aquatic stan- nationwide investigation of methylmercury in water, sediment, and fish tissues was dards in one sample each, and conducted (Krabbenhoft and others, 1999). Analysis of samples collected in the chromium exceeded standards in Santee Basin indicated that they had the greatest methylation efficiency (the ratio four samples. The samples with of methylmercury to total mercury) in the Nation. In other words, conditions at the elevated chromium concentrations sites sampled in the Santee Basin are such that a relatively small amount of ele- were not associated with any par- mental mercury in water can result in high concentrations of methylmercury being ticular land use; however, most of available for accumulation in fish tissue. The types of sites sampled were primarily these samples were collected at blackwater streams, which typically have large amounts of dissolved organic car- sites in the Piedmont. This suggests bon and low dissolved oxygen concentrations. The bacteria that convert elemental that the elevated concentrations mercury to methylmercury thrive under these conditions. Many of the streams that may be naturally occurring as a are covered by State fish-consumption advisories are blackwater streams. result of geologic conditions in the Piedmont. Regional differences in bed sedi- NAWQA STUDY AREAS SAMPLED FOR THE NATIONAL PILOT ment trace-metal concentrations STUDY OF MERCURY CONTAMINATION were observed in the study area. In GREAT SALT LAKE BASINS general, a decrease in the bed-sedi- LOWER TENNESSEE RIVER BASIN ment concentrations of arsenic, OAHU ISLAND chromium, copper, nickel, and zinc SACRAMENTO BASIN occurs from the Blue Ridge south- TRINITY RIVER BASIN eastward across the Piedmont to ALLEGHENY AND MONONGAHELA BASINS the Coastal Plain. In the same MOBILE RIVER AND TRIBUTARIES direction, an increase in the bed- NORTHERN ROCKIES INTERMONTANE BASINS sediment concentrations of lead, NEVADA BASIN AND RANGE mercury, and selenium occurs. COOK INLET BASIN These differences are likely a result DELAWARE RIVER BASIN of geologic differences among the GREAT AND LITTLE MIAMI RIVER BASINS areas (Abrahamsen, 1999). UPPER COLORADO BASIN A comparison of land use with YELLOWSTONE RIVER BASIN bed sediment trace-element con- ACADIA-PONTCHARTRAIN SANTA ANA RIVER centrations indicates that lead is LONG ISLAND AND NEW JERSEY COASTAL DRAINAGES significantly higher in sediment UPPER ILLINOIS RIVER BASIN from urban streams than in sedi- NEW ENGLAND COASTAL BASINS ment from forested streams. SOUTH FLORIDA Neither agricultural nor mixed SANTEE BASIN land-use streams had significantly higher concentrations of lead than 0 0.02 0.04 0.06 0.08 0.10 0.12 forested streams (Abrahamsen, AVERAGE METHYLMERCURY TO TOTAL 1999). MERCURY RATIO FOR WATER AND SEDIMENT

14 Water Quality in the Santee River Basin and Coastal Drainages

Trace Elements Accumulated health risk. Consumption adviso- because of high levels of mercury in Clam Tissue and Fish ries generally are not applied to in 49 rivers and reservoirs in the Livers clams because few humans con- Santee Basin, including the Edisto Trace metals are naturally sume them. The South Carolina River. occurring and were detected in all Department of Health and Environ- fish liver and clam tissue samples mental Control (2000) has issued collected. Nine trace elements fish-consumption advisories (arsenic, cadmium, chromium, 6 5 copper, lead, mercury, nickel, sele- 5 nium, and zinc) have been classi- Arsenic 4 4 fied as priority pollutants because 3 Cadmium they are toxic to aquatic organisms 3 2 in low concentrations (Code of 2 Federal Regulations, 1996). Of 1 1 these nine metals, concentrations of cadmium, copper, selenium, and 0 0 zinc were higher in clams and fish 80 200 70 liver tissue than those measured in 60 150 sediment. Carp liver tissue con- 50 Chromium Copper tained significantly higher concen- 40 100 trations of these metals than those 30 in clams and bed sediment, indicat- 20 50 ing that the metals accumulate in 10 fish livers. Concentrations of 0 0 arsenic, chromium, lead, and 40 10 nickel were significantly lower in 35 30 8 tissues than in sediment, suggest- Lead 25 6 Selenium ing that these metals do not accu- 20 mulate in tissues (fig. 15). 15 4 Concentrations of mercury were 10 2 higher in clam tissue than in sedi- 5 ment and fish livers. Although data 0 0 suggest that some metals accumu- 30 600 late in tissues, most metals do not 25 500 Nickel have criteria for assessing risk to 20 400 Zinc human health or aquatic wildlife

MEDIAN CONCENTRATION OF TRACE ELEMENTSTRACE IN BEDOF SEDIMENTTISSUE,MEDIAN IN AND CONCENTRATION MICROGRAMS PER KILOGRAM 15 300 associated with fish consumption. Concentrations of mercury in 10 200 clams and fish liver tissue from the 5 100 Edisto River were 24 and 8 times 0 0 greater, respectively, than the South Carolina action level for issuance of a fish-consumption FISH LIVER FISH LIVER CLAM TISSUE advisory. Data collected in the CLAM TISSUE BED SEDIMENT BED SEDIMENT NAWQA Program cannot be used to assess potential risk to human Figure 15. Cadmium, copper, selenium, and zinc were detected at higher concentrations health because fish livers were in clam and fish tissue than in sediment, suggesting that they accumulate in the tissues. Conversely, arsenic, chromium, lead, and nickel were detected in lower concentrations in used for analyses, whereas fish fil- tissues than in sediment, indicating that these metals do not accumulate in the tissues. lets are needed to assess human-

Major Findings 15 Radon Exceeded Proposed Standards in Many Wells EXPLANATION Ninety-six percent of the 90 AQUIFERS wells sampled in drinking-water Blue Ridge supply aquifers of the Santee Basin Piedmont North Carolina Sandhills contained measurable quantities of South Carolina Floridan radon, a colorless, odorless gas that can cause cancer in humans. The RADON CONCENTRATION Less than 300 picocuries gas results from the radioactive per liter decay of uranium in rocks and soil Greater than 300 but less than 4,000 picocuries per liter and can enter homes directly from Greater than 4,000 the soil or in drinking water sup- picocuries per liter plied by wells. Radon is a health risk through direct inhalation of the gas and from drinking water contaminated with radon. Of the 90 wells sampled, radon exceeded the USEPA’s (1999) proposed maximum contaminant level (MCL) of 300 picocuries per liter (pCi/L) in 100, 47, and 17 percent of the wells in the Piedmont, Sandhills, and Floridan aquifers, respectively (fig. 16). For wells not Figure 16. Radon concentrations were highest in the Piedmont and meeting the MCL, the USEPA has Sandhills aquifers, resulting from naturally high levels of uranium in near-surface rocks and sediment. proposed an Alternative Maximum Contaminant Level (AMCL) of AMCL, the State or local water 4,000 pCi/L. To comply with the utility must develop indoor air radon-reduction programs and RADON CONCENTRATIONS WERE HIGH reduce radon levels in drinking IN THE SANTEE BASIN water to 4,000 pCi/L. Of the wells that were sampled in the Piedmont, Sandhills, and Floridan aquifers, 20 Radon concentrations in the Santee Basin were among the highest measured in percent, zero percent, and less than the Nation. These high concentrations result from radioactive decay of naturally 1 percent, respectively, exceeded occurring minerals in the soil and rock that underlie the study area and compose the proposed AMCL. the aquifer in the Piedmont part of the study area. The Piedmont metamorphic Wells in the Piedmont had much rocks are present in many eastern coastal States and probably account for the higher concentrations of radon, on high radon concentrations observed in Study Units located in those States. average, than wells sampled in the Sandhills and Floridan aquifers (fig. 16). This results from the greater relative abundance of min-

EXPLANATION erals containing uranium in the RADON--222 IN GROUND WATER Study Units with radon concentrations metamorphic rocks that compose exceeding: 1,000 picocuries per liter (pCi/L) the Piedmont aquifer. The same 600 pCi/L in at least 25 percent of samples bedrock underlies the Sandhills and 300 pCi/L in at least 25 percent of samples Santee 300 pCi/L in less than 25 percent of samples Floridan aquifers, but generally at Basin No data depths ranging from several hun- dred to several thousand feet.

16 Water Quality in the Santee River Basin and Coastal Drainages

Volatile Organic Compounds tion in one well exceeded a drink- makes it difficult to attribute Were Common in Urban ing-water advisory. detected compounds to particular Ground Water Some of the most frequently homes or businesses, posing a problem for scientists who seek to All but 3 of 30 monitoring wells detected compounds included establish the relative importance of installed in commercial and resi- trichloromethane, chloromethane, these sources and for regulators dential areas of Columbia, S.C., and bromodichloromethane. These who seek to educate the public or contained a variety of volatile compounds can result from the control the release of toxic sub- organic compounds (VOCs), a chlorination of drinking water and stances. group of chemicals that includes can enter ground water by infiltra- gasoline additives, solvents, and tion from irrigation systems or Volatile Organic Compounds in disinfection by-products (Reuber, from leaky water-supply lines. Streams Can Result from Ground- 1999). Thirty-five such com- Other VOCs that were detected Water Discharge and Urban Runoff pounds were detected. Most wells were solvents, such as TCE, tetra- contained three or more VOCs, and chloroethene, and acetone. These Ten VOCs were detected in one well contained 15 different compounds have commercial and seven monthly stream-water sam- VOCs. industrial uses as degreasers and ples that were collected from Gills Most of the VOC detections dry-cleaning solvents, but they are Creek, an urban stream in the were at extremely low levels. The often used in households for simi- Columbia metropolitan area. five VOCs detected with the high- lar purposes. The gasoline addi- MTBE, chloromethane, methyl- est concentrations were methyl tives MTBE and TAME and the benzene, chlorobenzene, and ace- tert-butyl ether (MTBE), trichloro- gasoline component benzene also tone were detected most frequently. ethene (TCE), acetone, tert-amyl were detected in Columbia’s None of the VOCs detected in Gills methyl ether (TAME), and trichlo- ground water. These compounds Creek were at concentrations romethane. Of the 35 detected can enter ground water from leak- exceeding drinking-water or VOCs, 14 have established drinking gasoline storage tanks, spills, aquatic-life standards. Six of the ing-water standards; of these, only and potentially through atmo- VOCs detected do not have stan- TCE exceeded the standard. Cur- spheric deposition (Lopes, 1998). dards. rently there is no standard for The diffuse, nonpoint nature of VOCs have many sources, MTBE, but the MTBE concentra- sources of VOCs in ground water including contaminated precipitation, surface-water runoff, and ground-water discharge. Though the sources are diffuse and hard to measure directly, inferences can be made about the likely sources. For example, samples collected in Gills Creek while the water level was ris- ing during a rainstorm indicate that as streamflow increased, the concentration of acetone increased. This suggests that the source of acetone in the samples was from contaminated precipitation or stormwater runoff (Lopes and others, 2000). If the acetone resulted from continuously discharging ground water, the concentration would be expected to decrease as dilution by rainfall and Shallow ground water in the Columbia, S.C., metropolitan area contains a variety of volatile organic compounds, but mostly at low concentrations. runoff increased.

Major Findings 17 Drinking-Water Aquifers Had about twice as many wells in the Low Concentrations of Sandhills aquifers contain VOCs as Volatile Organic Compounds those in the Floridan and Piedmont Of the 90 wells sampled in the aquifers. The more frequent occur- Piedmont, Sandhills, and Floridan rence of VOCs in the Sandhills aquifers, 62 contained detectable aquifers probably relates to their concentrations of VOCs. All of the greater susceptibility to contamina- 28 compounds detected met tion. USEPA drinking-water standards; Data on VOCs in drinking-water however, 19 of the compounds did aquifers indicate that although not have standards. The VOCs these compounds are widespread, measured had widely ranging concentrations are sufficiently low detection limits, making compari- that human health is not immedi- sons among compounds and aqui- ately at risk. However, the fact that fers difficult. A subset of the detections were so frequent sug- compounds having detection limits gests that aquifers are susceptible of 0.05 microgram per liter (µg/L) to contamination and should be or lower was used to make compar- carefully monitored. isons. This comparison shows that Stormwater samples for volatile organic compounds were collected by using special samplers developed for the NAWQA Program. Ground water affects the quality of surface water Presently, surface water is used for most public water supplies in the During the summer of 1996, 20 Columbia metropolitan area. However, the quality of these supplies is largely different VOCs were detected at controlled by ground-water quality, especially during summer months. In low concentrations in individual areas of the basin with sandy soils, such as the Sandhills, flow in streams is samples collected at 16 surface- contributed mostly by discharge from ground water. Discharging ground water sites scattered throughout the water transports contaminants, including VOCs, that can result in water- Gills Creek Basin. The compounds quality problems in streams and lakes. Consequently, the health of aquatic detected in the highest concentra- organisms and surface-water drinking supplies can be affected by the tions included MTBE, 1,1-dichlo- chemical quality of shallow ground water discharged to streams and roethene, trichloroethene, reservoirs. Several streams in the metropolitan area, including Penn Branch methylbenzene, and 1,2-dibromo- and Jackson Creek, have high concentrations of nutrients and pesticides that 3-chloropropane—all solvents evidence suggests result from ground-water discharge (Maluk, 1999). except for MTBE, which is a gasoline additive. Fifteen of the compounds detected in surface water also were present in the Columbia ground-water samples. This result is not surprising because the samples were collected during low streamflow conditions when the ground-water contribution to Gills Creek is greatest; consequently, VOCs from contaminated ground water most likely would be detected in stream samples.

18 Water Quality in the Santee River Basin and Coastal Drainages

Urban and Agricultural The highest bacterial concentra- Streams Had High tions measured were at agricultural Concentrations of Bacteria sites, such as Cow Castle Creek Thirteen of 17 streams sampled and Indian Creek, N.C., which had for fecal coliform bacteria had at concentrations of 21,600 and least one sample that exceeded the 12,000 col/100 mL, respectively. South Carolina single-sample The highest concentrations standard of 400 colonies per 100 observed in urban streams were milliliters (cols/100 mL; South much lower—around 2,000 col/100 Bacterial cultures were prepared and Carolina Department of Health and mL. Forested streams generally had the lowest peak concentrations, counted in a mobile field laboratory Environmental Control, 1992). and in the USGS South Carolina Dis- ranging from about 500 to 1,000 This standard was implemented to trict laboratory. col/100 mL. Samples were col- reduce the risk of gastrointestinal 2 disorders that are associated with lected under all flow conditions, mi . Because major rivers and recreational contact with water and higher concentrations as well small streams have similar sources containing elevated levels of as standard exceedances tended to of bacteria, the most likely reason bacteria. All concentrations occur at higher streamflows. for the differences in bacterial lev- measured in this report were els is dilution by the larger flows in Stream Size is Important compared to South Carolina the major rivers. standards for consistency; North All of the regularly monitored Sources of Bacteria Carolina does not recognize a small streams exceeded the South single-sample standard. Carolina single-sample standard A comparison of bacterial con- Urban and agricultural streams for bacteria. Most large rivers did centrations to the physical and had more concentrations of bacte- not exceed the standard during the chemical parameters of the water ria that exceeded standards than period sampled, including the indicate that surface-water runoff forested and mixed land-use Wateree, Saluda, Congaree, and accounts for much of the elevated streams (fig. 17). Several creeks Edisto Rivers. The median bacte- fecal coliform concentrations repeatedly had high concentrations rial concentrations in streams with (Wilhelm and Maluk, 1998). Bacte- of bacteria. For example, one of the drainage areas larger than 100 rial concentrations increased as 2 urban streams sampled, Brushy square miles (mi ) were signifi- streamflow, organic nitrogen, Creek, exceeded the standard in 60 cantly lower than those in streams organic carbon, phosphorus, and percent of the samples collected. with drainage areas less than 100 suspended-sediment concentrations increased. Because increases in 50 these parameters usually result from surface-water runoff, the 40 implication is that the increase in bacteria also resulted from runoff. 30 In agricultural areas, bacteria in runoff may result from applications of manure to fields and from ani- 20 mal holding and feeding areas. Urban sources include runoff from 10 lawns containing pet wastes, leaking or failed septic tanks and sewer

PERCENTAGE OF SAMPLES EXCEEDING SOUTH PERCENTAGE CAROLINA BACTERIA STANDARDS BACTERIA CAROLINA 0 lines, and municipal or industrial Forested Urban Agricultural Mixed discharges. Bacterial contamina- LAND USE IN BASIN tion in forested areas most likely Figure 17. Urban and agricultural streams had more concentrations results from fecal contamination by of bacteria that exceeded South Carolina State standards than wildlife. forested and mixed land-use streams.

Major Findings 19 Biological Communities 0.05 Reflected Land-Use ATRAZINE Differences 0.04 AMMONIA Biological communities that inhabit streams in Santee Basin agricultural and urban areas were 0.03 indicative of degraded water quality compared to those that inhabit 0.02 streams that drain forested areas. Fish that have a low tolerance for 0.01 contamination make up a smaller percentage of the fish community at agricultural and urban sites than OF AMMONIA AND MEDIAN CONCENTRATION PER LITER IN MICROGRAMS ATRAZINE, 0 at forested sites (fig. 18). This can Forested Agricultural Urban Mixed result because fish such as darters 35 and shiners that are sensitive to contaminants do not thrive at 30 EPT TAXA degraded sites. Other species such CONTAMINANT-INTOLERANT 25 as catfish, redbreast sunfish, and FISH SPECIES some minnows that are relatively 20 unaffected by contaminants will take the place of the more sensitive 15 fish. 10 Urban and agricultural streams also had lower numbers of inverte- 5 brate species that are intolerant of contaminants than forested and 0 NUMBER OF EPHEMEROPTERA, PLECOPTERA, NUMBER OF EPHEMEROPTERA, AND PERCENTAGE TAXA TRICHOPTERA AND FISH SPECIES OF CONTAMINANT-INTOLERANT mixed land-use streams. This is Forested Agricultural Urban Mixed evidenced by the lower numbers of Figure 18. Compared to forested sites, urban and agricultural sites Ephemeroptera, Plecoptera, and have higher concentrations of atrazine and ammonia as well as lower Trichoptera (EPT) taxa, a group of numbers of fish and invertebrates that are intolerant of contamination. aquatic insects that are relatively uses the presence or absence of intolerant of contamination, at aquatic habitats, can affect aquatic EPT taxa as an indicator of aquatic urban and agricultural sites. The community health in ways that are USEPA (Plafkin and others, 1989) community health. similar to those that result from Water-quality constituents and changes in water quality. In addi- contaminant-intolerant species are tion, sample sites were located in related (fig.18). Median concentra- several different physiographic tions of ammonia, a nutrient asso- provinces, including the Blue ciated with wastewater discharges, Ridge, Piedmont, and Coastal and atrazine, an agricultural and Plain. Differences in species distri- turfgrass herbicide, are highest at butions and habitat in these differ- urban and agricultural sites, corre- ent settings can make comparisons sponding to low numbers of con- difficult to interpret. Most likely, a taminant-intolerant fish and combination of water quality and invertebrate species. This suggests habitat disturbance associated with that these water-quality constitu- agricultural and urban land uses Over 85 fish species were identified ents have an effect on the aquatic results in the observed differences during ecological sampling in the community; however, other factors, in biological communities. Santee Basin. primarily those associated with

20 Water Quality in the Santee River Basin and Coastal Drainages

SANTEE BASIN STREAMS WERE IN THE MIDDLE OF NATIONAL BIOLOGICAL RANKINGS

Algal Siltation Index Algal data collected in each of the NAWQA Study Units were combined and compared to show differences in the percentage of species that are able to avoid burial by sediment (Bahls and others, 1992). High percentages of these mobile algae are indicative of siltation of benthic habitats. Two sites in the Santee Basin were in the highest 25-percent category. One of these sites is the Edisto River, a blackwater river

Santee that has low light penetration.The high Basin ranking at this site may result from low- light conditions that favor mobile algal species. Other variables that can lower light levels in streams can affect this index, including turbidity and forest

*Higher values suggest a more degraded stream site canopy closure.

Invertebrate Status Index A multimetric index was developed to compare invertebrate populations nationally. The index is an average of 11 metrics that summarize changes in richness, tolerance, trophic condition, and dominance associated with water- quality degradation. Only one site in the Santee Basin, an urban stream, was placed in the highest 25-percent category. The remaining Santee Basin sites were in the middle category, except for Jacob Fork River and McTier Creek, which were in the lowest category. Both of these sites represent Santee the least degraded water quality in the Basin study area and were located in areas with the least effects of human activity. Nationally, urban and agricultural sites tended to have the most degraded invertebrate communities according to *Higher values suggest a more degraded stream site this index.

Major Findings 21 STUDY UNIT DESIGN

STREAM CHEMISTRY AND BIOLOGY Fixed sites were sampled to examine differences in streamwater quality due to the environmental setting, a combination of land use, EXPLANATION geology, physiography, and climate. Intensive fixed sites were a FIXED SITE subset of fixed sites that were sampled more frequently to deter- INTENSIVE FIXED SITE mine the occurrence and seasonal variability of pesticides. Aquatic BED SEDIMENT AND community structure, including algae, fish, and macroinvertebrates, TISSUE SITES was studied at each fixed site to quantify the effects of water quality on stream biota. Synoptic studies focused on low streamflow conditions in an urban setting in Gills Creek, S.C., and a mixed land-use setting in the South Fork Catawba River Basin, N.C. Streambed sediments and fish and clam tissues were sampled to determine the occurrence and distribution of trace elements and organic compounds.

0 50 MILES EXPLANATION 0 50 KILOMETERS AQUIFERS Blue Ridge Piedmont Sandhills Floridan SUBUNIT SURVEY WELLS URBAN LAND-USE GROUND-WATER CHEMISTRY WELLS AGRICULTURAL LAND- USE WELLS Subunit surveys were conducted in three drinking-water FLOW-PATH STUDY SITE supply aquifers to assess overall water quality. Land-use studies in urban and agricultural settings evaluated the effects of these land uses on shallow ground water. An agricultural flow-path study examined the transport and fate of nutrients and pesticides in shallow ground water.

0 50 MILES 0 50 KILOMETERS EXPLANATION FORESTED WETLAND INITIATIVE CONGAREE SWAMP NATIONAL MONUMENT EDISTO RIVER SPECIAL STUDIES MERCURY STUDY The effects of a forested wetland on nutrient concentrations in stream water were studied as part of the Forested Wetland Initiative, a joint research project with the U.S. Forest Service. Baseline data on water quality and aquatic communities were collected in cooper- ation with the National Park Service at Congaree Swamp National Monument (Maluk and Abrahamsen, 1999). A study to determine the accumulation of mercury in fish tissues was conducted in the Edisto River Basin.

0 50 MILES 0 50 KILOMETERS

22 Water Quality in the Santee River Basin and Coastal Drainages

SUMMARY OF DATA COLLECTION IN THE SANTEE RIVER BASIN AND COASTAL DRAINAGES, 1995–98

Study Number of Sampling frequency What data were collected and why Types of sites sampled component sites and period Stream Chemistry and Biology Fixed sites Streamflow was measured continuously and samples were Streams draining basins ranging in size Monthly, plus 3–6 storms collected monthly for major ions, nutrients, organic car- from 14 to 7,850 square miles and repre- 13 (October 1995–Septem- bon, suspended sediment, bacteria, pesticides, and physi- senting forested, agricultural, urban, and ber 1997) cal properties to describe concentration, seasonal mixed land uses. Pesticides (February, May, variability, and loads. August 1996) Intensive fixed In addition to the above constituents, samples were ana- A subset of fixed sites draining agricul- Weekly during growing sites lyzed for dissolved pesticides to describe concentration tural, urban, and mixed land uses. 3 season (February 1996– and seasonal variability. October 1997) Urban synoptic Streamflow, major ions, nutrients, organic carbon, sus- Urban streams draining basins ranging in study pended sediment, bacteria, pesticides, volatile organic size from 0.5 to 59.4 square miles. 16 September 1996 compounds, and physical properties were determined under low-flow conditions to describe concentrations and spatial distributions. South Fork Streamflow, major ions, nutrients, organic carbon, sus- Mixed land use streams draining basins Catawba River pended sediment, bacteria, and physical properties were ranging in size from 5 to 350 square 20 October 1997 synoptic study determined under low-flow conditions to describe con- miles. centrations and spatial distributions. Streambed sed- Streambed sediments were analyzed for trace elements and Sediment depositional zones at all fixed Summer 1995 iments hydrophobic pesticides and other organic compounds to sites and other selected sites. 20 determine occurrence and spatial distribution. Aquatic biota Clams and fish livers were analyzed for trace metals, and All fixed sites and other selected sites. Summers 1995, 1996 clams and whole fish were analyzed for organic com- 20 pounds to determine occurrence and spatial distribution. Fixed site reach Fish, benthic invertebrates, algae, and aquatic and riparian Stream reaches located at or near fixed Once in 1996 or 1997; assessment habitats were sampled and described to assess aquatic sites. Sites represent the variety of land 13 Multiyear sites, once dur- biological community structure in different land uses and uses, geology, and physiography within ing 1996–98 associated habitats. the Santee Basin

Ground-Water Chemistry Study unit sur- Major ions, nutrients, pesticides, volatile organic com- Randomly chosen existing pubic supply, Sandhills—Summer 1996 vey pounds, dissolved organic carbon, trace metals, radon private domestic, irrigation, and indus- 90 (30 per Floridan—Spring 1999 and physical parameters analyzed in three major drink- trial supply wells in the Piedmont, aquifer) Piedmont—Fall 2000 ing-water aquifers to determine ground-water quality. Sandhills, and Floridan aquifers. Urban land-use Major ions, nutrients, pesticides, volatile organic com- Wells installed at randomly chosen com- Summer 1996 study pounds, dissolved organic carbon, and physical parame- mercial/residential land-use areas. 30 ters analyzed in shallow ground water in the Columbia, South Carolina, metropolitan area. Agricultural Major ions, nutrients, pesticides, dissolved organic carbon, Wells installed at randomly chosen row- Summer 1997 land-use study and physical parameters analyzed in shallow ground crop land-use areas. 30 water in row-crop agricultural lands of the lower Coastal Plain Flow-path Major ions, nutrients, pesticides, dissolved organic carbon, Multidepth wells installed along a ground- November 1997, April and study and physical parameters analyzed to determine fate and water flow path in the lower Coastal 34 August 1997 transport of pesticides and nutrients in an agricultural set- Plain. ting. Special Studies Forested Wet- Major ions, nutrients, and organic carbon analyzed Coosawhatchie River in the lower Coastal Approximately quarterly, land Initiative upstream and downstream from a forested wetland to Plain. 2 1996–97 compare changes in concentrations. Congaree Streamflow, major ions, nutrients, organic carbon, sus- Streams draining basins ranging in size Swamp pended sediment, bacteria, pesticides, and physical prop- from 32 to 70 square miles with agricul- 4 Quarterly 1996–98 National Mon- erties to describe concentrations and seasonal variability. tural, urban, and forested land uses that ument Fish, benthic invertebrates, algae, and aquatic habitat drain into Congaree Swamp. described to assess aquatic biological community structure.

Edisto mercury Sediment, stream water, aquatic insects, and vegetation, and Blackwater streams in the Edisto River study whole fish analyzed for elemental and methyl mercury to Basin and a reference site in the Pied- 5 Once in 1998 examine bioaccumulation of mercury. mont

Study Unit Design 23 GLOSSARY

Ammonia—A compound of nitrogen and hydrogen (NH3) that is a com- Intolerant organisms—Organisms that are not adaptable to human alter- mon by-product of animal waste. Ammonia readily converts to nitrate ations to the environment and thus decline in numbers where human in soils and streams. alterations occur. Aquatic-life criteria—Water-quality guidelines for protection of aquatic Invertebrate—An animal having no backbone or spinal column. life. Often refers to U.S. Environmental Protection Agency water- Major ions—Constituents commonly present in concentrations exceeding quality criteria for protection of aquatic organisms. 1.0 milligram per liter. Dissolved cations generally are calcium, mag- Aquifer—A water-bearing layer of soil, sand, gravel, or rock that will yield nesium, sodium, and potassium; the major anions are sulfate, chlo- usable quantities of water to a well. ride, fluoride, nitrate, and those contributing to alkalinity, most Atmospheric deposition—The transfer of substances from the air to the generally assumed to be bicarbonate and carbonate. surface of the Earth, either in wet form (rain, fog, snow, dew, frost, Maximum contaminant level (MCL)—Maximum permissible level of a hail) or in dry form (gases, aerosols, particles). contaminant in water that is delivered to any user of a public water Bedrock—General term for consolidated (solid) rock that underlies soils or system. MCLs are enforceable standards established by the U.S. other unconsolidated material. Environmental Protection Agency. Bed sediment—The material that temporarily is stationary in the bottom of Median—The middle or central value in a distribution of data ranked in a stream or other watercourse. order of magnitude. The median is also known as the 50th percentile. Concentration—The amount or mass of a substance present in a given vol- Metamorphic rock—Rock that has formed in the solid state in response to ume or mass of sample. Usually expressed as microgram per liter pronounced changes of temperature, pressure, and chemical environ- (water sample) or micrograms per kilogram (sediment or tissue sam- ment. ple). Method detection limit—The minimum concentration of a substance that Confined aquifer (artesian aquifer)—An aquifer that is completely filled can be accurately identified and measured with present laboratory with water under pressure and that is overlain by material that technologies. restricts the movement of water. Micrograms per liter (µg/L)—A unit expressing the concentration of con- Confining layer—A layer of sediment or lithologic unit of low permeabil- stituents in solution as weight (micrograms) of solute per unit volume ity that bounds an aquifer, (liter) of water; equivalent to one part per billion in most streamwater Contamination—Degradation of water quality compared to original or nat- and ground water. One thousand micrograms per liter equals 1 mg/L. ural conditions due to human activity. Milligrams per liter (mg/L)—A unit expressing the concentration of Degradation products—Compounds resulting from transformation of an chemical constituents in solution as weight (milligrams) of solute per organic substance through chemical, photochemical, and/or biochem- unit volume (liter) of water; equivalent to one part per million in most ical reactions. streamwater and ground water. One thousand micrograms per liter Denitrification—A process by which oxidized forms of nitrogen such as equals 1 mg/L. – nitrate (NO3 ) are reduced to form nitrites, nitrogen oxides, ammonia, Minimum reporting level (MRL)—The smallest measured concentration or free nitrogen: commonly brought about by the action of denitrify- of a constituent that may be reliably reported using a given analytical ing bacteria and usually resulting in the escape of nitrogen to the air. method. In many cases, the MRL is used when documentation for the Detect—To determine the presence of a compound. method detection limit is not available. DDT—Dichloro-diphenyl-trichloroethane. An organochlorine insecticide Monitoring well—A well designed for measuring water levels and testing no longer registered for use in the United States. ground-water quality. – Drainage area—The drainage area of a stream at a specified location is that Nitrate—An ion consisting of nitrogen and oxygen (NO3 ). Nitrate is a area, measured in a horizontal plane, which is enclosed by a drainage plant nutrient and is very mobile in soils. divide. Nutrient—Element or compound essential for animal and plant growth. Drinking-water standard or guideline—A threshold concentration in a Common nutrients in fertilizer include nitrogen, phosphorus, and public drinking-water supply, designed to protect human health. As potassium. defined here, standards are U.S. Environmental Protection Agency Pesticide—A chemical applied to crops, rights of way, lawns, or residences regulations that specify the maximum contamination levels for public to control weeds, insects, fungi, nematodes, rodents or other "pests." water systems required to protect the public welfare; guidelines have Phosphorus—A nutrient essential for growth that can play a key role in no regulatory status and are issued in an advisory capacity. stimulating aquatic growth in lakes and streams. Eutrophication—The process by which water becomes enriched with plant Study Unit—A major hydrologic system of the United States in which nutrients, most commonly phosphorus and nitrogen. NAWQA studies are focused. Study Units are geographically defined Fecal bacteria—Microscopic single-celled organisms (primarily fecal by a combination of ground- and surface-water features and generally coliforms and fecal streptococci) found in the wastes of warm- encompass more than 4,000 square miles of land area. blooded animals. Their presence in water is used to assess the sanitary Trace element—An element found in only minor amounts (concentrations quality of water for body-contact recreation or for consumption. Their less than 1.0 milligram per liter) in water or sediment; includes presence indicates contamination by the wastes of warm-blooded ani- arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc. mals and the possible presence of pathogenic (disease producing) Unconfined aquifer—An aquifer whose upper surface is a water table; an organisms. aquifer containing unconfined ground water. Flow path—An underground route for ground-water movement, extending Volatile organic compounds (VOCs)—Organic chemicals that have a high from a recharge (intake) zone to a discharge (output) zone such as a vapor pressure relative to their water solubility. VOCs include com- shallow stream. ponents of gasoline, fuel oils, and lubricants, as well as organic sol- Ground water—In general, any water that exists beneath the land surface, vents, fumigants, some inert ingredients in pesticides, and some by- but more commonly applied to water in fully saturated soils and geo- products of chlorine disinfection. logic formations. Water table—The point below the land surface where ground water is first Herbicide—A chemical or other agent applied for the purpose of killing encountered and below which the earth is saturated. Depth to the undesirable plants. See also Pesticide. water table varies widely across the country. Insecticide—A substance or mixture of substances intended to destroy or repel insects.

24 Water Quality in the Santee River Basin and Coastal Drainages REFERENCES

Abrahamsen, T.A., 1999, Trace elements in bed sediments and South Carolina: U.S. Geological Survey Fact Sheet FS–007– biota from streams in the Santee River Basin and coastal 98, 6 p. drainages, North and South Carolina, 1995–97: U.S. Geologi- Maluk, T.L., Reuber, E.J., and Hughes, W.B., 1998, Nutrients in cal Survey Water-Resources Investigations Report 99–4179, waters of the Santee River Basin and coastal drainages, North 26 p. and South Carolina, 1973–93: U.S. Geological Survey Water- Aucott,W.R., Davis, M.E., and Speiran, G.K., 1987, Geohydrologic Resources Investigations Report 97–4172, 60 p. framework of the Coastal Plain aquifers of South Carolina: Nolan, B.T., and Stoner, J.D., 2000, Nutrients in ground waters of U.S. Geological Survey Water-Resources Investigations the conterminous United States 1992–1995: Environmental Report 85-4271, 7 sheets. Science and Technology, v. 34, no. 7, p. 1156–1165. 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Major Findings 25

APPENDIX—WATER-QUALITY DATA FROM THE SANTEE RIVER BASIN AND COASTAL DRAINAGES IN A NATIONAL CONTEXT

For a complete view of Santee River Basin and coastal drainages data and for additional information about speciﬁc benchmarks used, visit our Web site at http://water.usgs.gov/nawqa/. Also visit the NAWQA Data Warehouse for access to NAWQA data sets at http://water.usgs.gov/nawqa/data.

This appendix is a summary of chemical concentrations Pesticides in water—Herbicides and biological indicators assessed in the Santee River Study-unit frequency of detection, in percent Basin and coastal drainages. Selected results for this National frequency of detection, in percent Study-unit sample size Study Unit are graphically compared to results from as Alachlor (Lasso, Bronco, Lariat, Bullet) ** many as 36 NAWQA Study Units investigated from 1991 to 55 44 | 53 14 20 | 43 1998 and to national water-quality benchmarks for human 17 45 | 18 health, aquatic life, or fish-eating wildlife. The chemical and 3 3 | 30 0 <1 | 28 biological indicators shown were selected on the basis of 2 1 | 88 frequent detection, detection at concentrations above a Atrazine (AAtrex, Atrex, Atred, Gesaprim) national benchmark, or regulatory or scientific importance. 96 88 | | 53 98 86 | | 43 The graphs illustrate how conditions associated with each 72 87 | | 18 land use sampled in the Santee River Basin and coastal 50 40 | 30 57 30 | 28 drainages compare to results from across the Nation, and 10 18 | 88 how conditions compare among the several land uses. 2,4-D (Aqua-Kleen, Lawn-Keep, Weed-B-Gone) Graphs for chemicals show only detected concentrations 4 15 | | 28 9 18 | | 33 and, thus, care must be taken to evaluate detection 0 11 | | 15 frequencies in addition to concentrations when comparing 0 <1 | 30 0 1 | 28 study-unit and national results. For example, tebuthiuron 0 <1 | 87 concentrations in Santee River Basin and coastal Deethylatrazine (Atrazine breakdown product) * ** 77 75 53 drainages agricultural streams were similar to the national 93 62 43 distribution, but the detection frequency was much higher 44 75 18 60 39 30 (66 percent compared to 22 percent). 43 28 28 10 19 88

CHEMICALS IN WATER Dinoseb (Dinosebe) 0 <1 28 Concentrations and detection frequencies, Santee River Basin | | and coastal drainages, 1995–98—Detection sensitivity varies among chemicals and, thus, frequencies are not directly comparable 0 1 | 30 2 <1 | 87 Detected concentration in Study Unit 66 38 Frequencies of detection, in percent. Detection frequencies Metolachlor (Dual, Pennant) were not censored at any common reporting limit. The left- 96 81 | | 53 28 64 | | 43 hand column is the study-unit frequency and the right-hand 67 83 | | 18 column is the national frequency 17 18 | 30 0 9 | 28 -- Not measured or sample size less than two 2 5 | 88 12 Study-unit sample size. For ground water, the number of samples is equal to the number of wells sampled Prometon (Pramitol, Princep) ** 57 44 | 53 95 86 | 43 National ranges of detected concentrations, by land use, in 36 33 60 | 18 NAWQA Study Units, 1991–98—Ranges include only samples 3 12 | 30 7 21 | 28 in which a chemical was detected 1 5 | 88 Streams in agricultural areas Simazine (Princep, Caliber 90) Streams in urban areas 81 61 | | 53 Streams and rivers draining mixed land uses 98 77 | | 43 61 74 | | 18 Shallow ground water in agricultural areas 7 21 | 30 Shallow ground water in urban areas 39 18 | 28 3 5 | 88 Major aquifers Lowest Middle Highest 25 50 25 Tebuthiuron (Spike, Tebusan) percent percent percent 66 22 | | 53 98 39 | | 43 94 32 | | 18 National water-quality benchmarks 7 3 | 30 National benchmarks include standards and guidelines related to 11 7 | 28 5 3 88 drinking-water quality, criteria for protecting the health of aquatic life, and | a goal for preventing stream eutrophication due to phosphorus. Sources include the U.S. Environmental Protection Agency and the Canadian 0.0001 0.001 0.01 0.1 1 10 100 1,000 Council of Ministers of the Environment CONCENTRATION, IN MICROGRAMS PER LITER | Drinking-water quality (applies to ground water and surface water) | Protection of aquatic life (applies to surface water only) Other herbicides detected | Prevention of eutrophication in streams not flowing directly into Acifluorfen (Blazer, Tackle 2S) ** lakes or impoundments Benfluralin (Balan, Benefin, Bonalan) * ** Bentazon (Basagran, Bentazone) ** No benchmark for drinking-water quality * Bromacil (Hyvar X, Urox B, Bromax) ** No benchmark for protection of aquatic life Butylate (Sutan +, Genate Plus, Butilate) **

26 Water Quality in the Santee River Basin and Coastal Drainages

Cyanazine (Bladex, Fortrol) Study-unit frequency of detection, in percent DCPA (Dacthal, chlorthal-dimethyl) * ** National frequency of detection, in percent Study-unit sample size 2,6-Diethylaniline (Alachlor breakdown product) * ** Diuron (Crisuron, Karmex, Diurex) ** Diazinon (Basudin, Diazatol, Neocidol, Knox Out) 6 16 | | 53 EPTC (Eptam, Farmarox, Alirox) * ** 81 70 43 0 39 | | 18 Ethalfluralin (Sonalan, Curbit) * ** | | 3 <1 | 30 Fenuron (Fenulon, Fenidim) * ** 11 2 | 28 Fluometuron (Flo-Met, Cotoran) ** 1 2 | 88 Linuron (Lorox, Linex, Sarclex, Linurex, Afalon) * Metribuzin (Lexone, Sencor) Dieldrin (Panoram D-31, Octalox, Compound 497) 2 6 | | 53 Molinate (Ordram) * ** 0 2 | | 43 0 2 18 Neburon (Neburea, Neburyl, Noruben) * ** | | Norflurazon (Evital, Predict, Solicam, Zorial) * ** 3 1 | 30 25 6 | 28 Oryzalin (Surflan, Dirimal) * ** 1 1 | 88 Pendimethalin (Pre-M, Prowl, Stomp) * ** Pronamide (Kerb, Propyzamid) ** Malathion (Malathion) 9 5 | | 53 Propham (Tuberite) ** 56 21 | | 43 Terbacil (Sinbar) ** 11 6 | | 18 Trifluralin (Treflan, Gowan, Tri-4, Trific) 0 <1 | 30 0 <1 | 28 0 <1 | 88 Herbicides not detected Acetochlor (Harness Plus, Surpass) * ** Parathion (Roethyl-P, Alkron, Panthion, Phoskil) * Bromoxynil (Buctril, Brominal) * 4 <1 | 53 5 1 | 43 Chloramben (Amiben, Amilon-WP, Vegiben) ** 0 <1 | 18 Clopyralid (Stinger, Lontrel, Transline) * ** 2,4-DB (Butyrac, Butoxone, Embutox Plus, Embutone) * ** Dacthal mono-acid (Dacthal breakdown product) * ** Dicamba (Banvel, Dianat, Scotts Proturf) Dichlorprop (2,4-DP, Seritox 50, Lentemul) * ** 0.0001 0.001 0.01 0.1 1 10 100 1,000 MCPA (Rhomene, Rhonox, Chiptox) CONCENTRATION, IN MICROGRAMS PER LITER MCPB (Thistrol) * ** Napropamide (Devrinol) * ** Pebulate (Tillam, PEBC) * ** Picloram (Grazon, Tordon) Other insecticides detected Propachlor (Ramrod, Satecid) ** Aldicarb (Temik, Ambush, Pounce) Propanil (Stam, Stampede, Wham) * ** Aldicarb sulfone (Standak, aldoxycarb) 2,4,5-T ** Carbofuran (Furadan, Curaterr, Yaltox) 2,4,5-TP (Silvex, Fenoprop) ** Fonofos (Dyfonate, Capfos, Cudgel, Tycap) ** Thiobencarb (Bolero, Saturn, Benthiocarb) * ** 3-Hydroxycarbofuran (Carbofuran breakdown product) * ** Triallate (Far-Go, Avadex BW, Tri-allate) * Methiocarb (Slug-Geta, Grandslam, Mesurol) * ** Triclopyr (Garlon, Grandstand, Redeem, Remedy) * ** Methomyl (Lanox, Lannate, Acinate) ** Oxamyl (Vydate L, Pratt) ** cis-Permethrin (Ambush, Astro, Pounce) * ** Pesticides in water—Insecticides Propoxur (Baygon, Blattanex, Unden, Proprotox) * ** Study-unit frequency of detection, in percent Insecticides not detected National frequency of detection, in percent Study-unit sample size Azinphos-methyl (Guthion, Gusathion M) * Disulfoton (Disyston, Di-Syston) ** Aldicarb sulfoxide (Aldicarb breakdown product) Ethoprop (Mocap, Ethoprophos) * ** 3 <1 | | 29 alpha-HCH (alpha-BHC, alpha-lindane) ** gamma-HCH (Lindane, gamma-BHC) 0 <1 | 30 Methyl parathion (Penncap-M, Folidol-M) ** 1 <1 | 85 Phorate (Thimet, Granutox, Geomet, Rampart) * ** Propargite (Comite, Omite, Ornamite) * ** Carbaryl (Carbamine, Denapon, Sevin) Terbufos (Contraven, Counter, Pilarfox) ** 9 9 | | 53 51 46 | | 43 0 16 | | 18 0 <1 | 30 11 2 | 28 0 1 | 88 Volatile organic compounds (VOCs) in ground water Chlorpyrifos (Brodan, Dursban, Lorsban) These graphs represent data from 16 Study Units, sampled from 1996 to 1998 60 18 | | 53 72 37 | | 43 0 20 | | 18 Study-unit frequency of detection, in percent 0 1 | 30 National frequency of detection in percent Study-unit sample size 7 1 | 28 0 <1 | 88 1 Carbon disulfide * p,p'-DDE 2 8 | | 53 0 2 43 6 4 | | 18 -- 30 0 | | 83 42 30 0 4 | 30 24 24 90 0 2 | 28 2 2 | 88 0.001 0.01 0.1 1 10 100 1,000 10,000

CONCENTRATION, IN MICROGRAMS PER LITER 0.0001 0.001 0.01 0.1 1 10 100 1,000 CONCENTRATION, IN MICROGRAMS PER LITER

Water-Quality Data in a National Context 27

Study-unit frequency of detection, in percent 1,1,1-Trichloroethane (Methylchloroform) National frequency of detection in percent Study-unit sample size Trichlorofluoromethane (CFC 11, Freon 11)

Chloromethane (Methyl chloride) 1 VOCs not detected Bromobenzene (Phenyl bromide) * Bromochloromethane (Methylene chlorobromide) -- 20 | 0 Bromoethene (Vinyl bromide) * 63 22 | 30 2 15 90 n-Butylbenzene (1-Phenylbutane) * | 3-Chloro-1-propene (3-Chloropropene) * Methyl tert-butyl ether (MTBE) 1-Chloro-2-methylbenzene (o-Chlorotoluene) 1-Chloro-4-methylbenzene (p-Chlorotoluene) 1,2-Dibromo-3-chloropropane (DBCP, Nemagon) -- 4 | 0 1,2-Dibromoethane (Ethylene dibromide, EDB) 23 16 30 3 6 | 90 Dibromomethane (Methylene dibromide) * | trans-1,4-Dichloro-2-butene ((Z)-1,4-Dichloro-2-butene) * 2,2-Dichloropropane * Trichloroethene (TCE) 1,3-Dichloropropane (Trimethylene dichloride) * trans-1,3-Dichloropropene ((E)-1,3-Dichloropropene) cis-1,3-Dichloropropene ((Z)-1,3-Dichloropropene) -- 3 | 0 27 8 | 30 1,1-Dichloropropene * 2 5 | 90 Diisopropyl ether (Diisopropylether (DIPE)) * Ethenylbenzene (Styrene) Trichloromethane (Chloroform) 1 Ethyl methacrylate * Ethyl tert-butyl ether (Ethyl-t-butyl ether (ETBE)) * 1-Ethyl-2-methylbenzene (2-Ethyltoluene) * -- 35 | 0 73 51 | 30 Hexachlorobutadiene 46 30 | 90 1,1,1,2,2,2-Hexachloroethane (Hexachloroethane) 2-Hexanone (Methyl butyl ketone (MBK)) * 0.001 0.01 0.1 1 10 100 1,000 10,000 Methyl acrylonitrile * Methyl-2-methacrylate (Methyl methacrylate) * CONCENTRATION, IN MICROGRAMS PER LITER 4-Methyl-2-pentanone (Methyl isobutyl ketone (MIBK)) * 1 Many of the samples in this study were diluted prior to laboratory analysis and therefore the Methyl-2-propenoate (Methyl acrylate) * actual detection frequency may be larger than the value listed. Naphthalene 2-Propenenitrile (Acrylonitrile) n-Propylbenzene (Isocumene) * Other VOCs detected 1,1,1,2-Tetrachloroethane tert-Amylmethylether (tert-amyl methyl ether (TAME)) * 1,2,3,4-Tetramethylbenzene (Prehnitene) * Benzene 1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 113) * Bromodichloromethane (Dichlorobromomethane) 1,2,4-Trichlorobenzene Bromomethane (Methyl bromide) 1,2,3-Trichlorobenzene * 2-Butanone (Methyl ethyl ketone (MEK)) * 1,1,2-Trichloroethane (Vinyl trichloride) sec-Butylbenzene * 1,2,3-Trichloropropane (Allyl trichloride) tert-Butylbenzene * 1,2,3-Trimethylbenzene (Hemimellitene) * Chlorobenzene (Monochlorobenzene) 1,2,4-Trimethylbenzene (Pseudocumene) * Chlorodibromomethane (Dibromochloromethane) 1,3,5-Trimethylbenzene (Mesitylene) * Chloroethane (Ethyl chloride) * Chloroethene (Vinyl chloride) 1,2-Dichlorobenzene (o-Dichlorobenzene) 1,3-Dichlorobenzene (m-Dichlorobenzene) Nutrients in water 1,4-Dichlorobenzene (p-Dichlorobenzene) Study-unit frequency of detection, in percent Dichlorodifluoromethane (CFC 12, Freon 12) National frequency of detection, in percent Study-unit sample size 1,2-Dichloroethane (Ethylene dichloride) 1,1-Dichloroethane (Ethylidene dichloride) * Ammonia, as N * ** 76 84 111 1,1-Dichloroethene (Vinylidene chloride) 86 86 102 trans-1,2-Dichloroethene ((E)-1,2-Dichlorothene) 64 75 181 cis-1,2-Dichloroethene ((Z)-1,2-Dichloroethene) 27 78 30 73 71 30 Dichloromethane (Methylene chloride) 64 70 89 1,2-Dichloropropane (Propylene dichloride) Diethyl ether (Ethyl ether) * Dissolved ammonia plus organic nitrogen, as N * ** 52 78 111 1,2-Dimethylbenzene (o-Xylene) 69 74 102 1,3 & 1,4-Dimethylbenzene (m-&p-Xylene) 77 62 181 1-4-Epoxy butane (Tetrahydrofuran, Diethylene oxide) * 7 28 30 17 30 30 Ethylbenzene (Phenylethane) 25 24 89 Iodomethane (Methyl iodide) * Isopropylbenzene (Cumene) * Dissolved nitrite plus nitrate, as N ** p-Isopropyltoluene (p-Cymene) * 100 95 | 111 94 97 | 102 Methylbenzene (Toluene) 83 91 | 181 2-Propanone (Acetone) * 87 81 | 30 1,1,2,2-Tetrachloroethane * 87 74 | 30 60 71 | 89 Tetrachloroethene (Perchloroethene) Tetrachloromethane (Carbon tetrachloride) 1,2,3,5-Tetramethylbenzene (Isodurene) * 0.001 0.01 0.1 1 10 100 1,000 10,000 100,000 Tribromomethane (Bromoform) CONCENTRATION, IN MILLIGRAMS PER LITER

28 Water Quality in the Santee River Basin and Coastal Drainages

Study-unit frequency of detection, in percent Other trace elements detected Study-unit sample size National frequency of detection, in percent Selenium Orthophosphate, as P * ** Uranium 86 79 111 26 72 103 Trace elements not detected 88 74 181 Cadmium 40 59 30 10 52 30 69 61 89 CHEMICALS IN FISH TISSUE Total phosphorus, as P * ** AND BED SEDIMENT 95 92 | 111 91 90 | 102 Concentrations and detection frequencies, Santee River Basin 97 88 181 | and coastal drainages, 1995–98—Detection sensitivity varies among chemicals and, thus, frequencies are not directly comparable among chemicals. Study-unit frequencies of detection are based on small sample sizes; the applicable sample size is specified in each graph

0.001 0.01 0.1 1 10 100 1,000 10,000 100,000 Detected concentration in Study Unit CONCENTRATION, IN MILLIGRAMS PER LITER 66 38 Frequencies of detection, in percent. Detection frequencies were not censored at any common reporting limit. The left- Dissolved solids in water hand column is the study-unit frequency and the right-hand column is the national frequency Study-unit frequency of detection, in percent -- National frequency of detection, in percent Study-unit sample size Not measured or sample size less than two 12 Study-unit sample size Dissolved solids * ** 100 100 111 100 100 103 National ranges of concentrations detected, by land use, in 36 100 100 179 NAWQA Study Units, 1991–98—Ranges include only samples 100 100 30 in which a chemical was detected 100 100 30 100 100 90 Fish tissue from streams in agricultural areas Fish tissue from streams in urban areas Fish tissue from streams draining mixed land uses 0.001 0.01 0.1 1 10 100 1,000 10,000 100,000 Sediment from streams in agricultural areas CONCENTRATION, IN MILLIGRAMS PER LITER Sediment from streams in urban areas Sediment from streams draining mixed land uses Trace elements in ground water Lowest Middle Highest 25 50 25 percent percent percent Study-unit frequency of detection, in percent National frequency of detection, in percent Study-unit sample size National benchmarks for fish tissue and bed sediment Arsenic National benchmarks include standards and guidelines related to criteria for protection of the health of fish-eating wildlife and aquatic organisms. Sources include the U.S. Environmental Protection Agency, -- 58 | 0 other Federal and State agencies, and the Canadian Council of -- 36 | 0 Ministers of the Environment 4 37 | 90 | Protection of fish-eating wildlife (applies to fish tissue) Chromium | Protection of aquatic life (applies to bed sediment) * No benchmark for protection of fish-eating wildlife -- 85 | 0 -- 79 | 0 ** No benchmark for protection of aquatic life 57 73 | 90

Lead

-- 9 | 0 Organochlorines in fish tissue (whole body) -- 5 | 0 37 16 | 90 and bed sediment

Zinc Study-unit frequency of detection, in percent National frequency of detection, in percent Study-unit sample size

Total Chlordane (sum of 5 chlordanes) -- 28 | 0 -- 29 | 0 -- 38 | 1 62 66 | 90 -- 75 | 1 100 56 | 2 0 9 | 7 0.01 0.1 1 10 100 1,000 10,000 100,000 67 57 | 3 0 11 | 8 CONCENTRATION, IN MICROGRAMS PER LITER o,p'+p,p'-DDD (sum of o,p'-DDD and p,p'-DDD) * -- 49 1 Radon-222 -- 69 1 50 50 2 29 27 | 7 33 50 | 3 -- 99 | 0 12 20 | 8 -- 100 | 0 93 97 | 90 0.1 1 10 100 1,000 10,000 100,000

0.01 0.1 1 10 100 1,000 10,000 100,000 CONCENTRATION, IN MICROGRAMS PER KILOGRAM CONCENTRATION, IN PICOCURIES PER LITER (Fish tissue is wet weight; bed sediment is dry weight) Water-Quality Data in a National Context 29

Study-unit frequency of detection, in percent Semivolatile organic compounds (SVOCs) National frequency of detection, in percent Study-unit sample size in bed sediment p,p'-DDE * ** -- 90 1 Study-unit frequency of detection, in percent -- 94 1 100 92 3 National frequency of detection, in percent Study-unit sample size 71 48 7 33 62 3 Acenaphthene 62 39 8

o,p'+p,p'-DDE (sum of o,p'-DDE and p,p'-DDE) * -- 90 1 14 10 | 7 -- 94 1 33 54 | 3 100 92 2 50 27 | 8 71 48 | 7 33 62 | 3 Anthracene 62 39 | 8

Total DDT (sum of 6 DDTs) ** 43 37 | 7 -- 90 | 1 100 89 3 -- 94 | 1 88 56 | 8 100 93 | 2 | 71 49 7 33 66 3 Anthraquinone ** 62 41 8

Dieldrin (Panoram D-31, Octalox) * -- 53 1 14 21 7 -- 42 1 100 83 3 67 38 3 62 39 8 0 13 | 7 33 30 | 3 9H-Carbazole ** 0 9 | 8

Dieldrin+aldrin (sum of dieldrin and aldrin) ** 14 19 7 -- 52 | 1 100 76 3 -- 42 | 1 50 33 8 50 38 | 2 0 13 7 33 29 3 Dibenzothiophene ** 0 9 8

Heptachlor+heptachlor epoxide ** 29 12 7 -- 9 | 1 67 64 3 -- 9 | 1 62 30 8 50 14 | 2 0 1 7 0 2 3 1,4-Dichlorobenzene (p-Dichlorobenzene) ** 0 <1 8

Total PCB 2 -- 38 | 1 0 6 3 -- 81 | 1 12 7 8 100 66 | 2 0 2 | 7 0 21 | 3 2,6-Dimethylnaphthalene ** 0 9 | 8

57 65 7 0.1 1 10 100 1,000 10,000 100,000 67 74 3 CONCENTRATION, IN MICROGRAMS PER KILOGRAM 62 77 8 (Fish tissue is wet weight; bed sediment is dry weight) bis(2-Ethylhexyl)phthalate ** 2 The national detection frequencies for total PCB in sediment are biased low because about 30 percent of samples nationally had elevated detection levels compared to this Study Unit. See http://water.usgs.gov/nawqa/ for additional information. 100 91 7 100 99 3 Other organochlorines detected 100 95 8 DCPA (Dacthal, chlorthal-dimethyl) * ** o,p'+p,p'-DDT (sum of o,p'-DDT and p,p'-DDT) * Fluoranthene Heptachlor epoxide (Heptachlor breakdown product) * Hexachlorobenzene (HCB) ** Mirex (Dechlorane) ** 100 66 | 7 100 97 | 3 88 78 | 8 Organochlorines not detected Chloroneb (Chloronebe, Demosan) * ** 9H-Fluorene (Fluorene) Endosulfan I (alpha-Endosulfan, Thiodan) * ** Endrin (Endrine) gamma-HCH (Lindane, gamma-BHC, Gammexane) * 14 22 | 7 67 76 | 3 Total-HCH (sum of alpha-HCH, beta-HCH, gamma-HCH, and 75 41 8 delta-HCH) ** | Isodrin (Isodrine, Compound 711) * ** p,p'-Methoxychlor (Marlate, methoxychlore) * ** 0.1 1 10 100 1,000 10,000 100,000 o,p'-Methoxychlor * ** CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT cis-Permethrin (Ambush, Astro, Pounce) * ** trans-Permethrin (Ambush, Astro, Pounce) * ** Toxaphene (Camphechlor, Hercules 3956) * **

30 Water Quality in the Santee River Basin and Coastal Drainages

Study-unit frequency of detection, in percent 4-Chlorophenyl-phenylether ** National frequency of detection, in percent Study-unit sample size 1,2-Dichlorobenzene (o-Dichlorobenzene) ** 1,3-Dichlorobenzene (m-Dichlorobenzene) ** N-Nitrosodiphenylamine ** 3,5-Dimethylphenol ** 2,4-Dinitrotoluene ** Isophorone ** 0 2 7 33 10 3 Nitrobenzene ** 0 4 8 N-Nitrosodi-n-propylamine ** Pentachloronitrobenzene ** Phenanthrene 1,2,4-Trichlorobenzene **

71 50 | 7 100 93 | 3 75 66 | 8

Phenol ** Trace elements in fish tissue (livers) and bed sediment

100 81 7 100 82 3 Study-unit frequency of detection, in percent 88 80 8 National frequency of detection, in percent Study-unit sample size

Pyrene Arsenic * -- 56 1 -- 38 1 100 76 4 86 64 | 7 100 99 | 7 100 95 | 3 100 98 | 3 88 76 | 8 100 97 | 7

Cadmium * 0.1 1 10 100 1,000 10,000 100,000 -- 77 1 -- 72 1 CONCENTRATION, IN MICROGRAMS PER KILOGRAM, DRY WEIGHT 100 95 4 100 98 | 7 100 100 | 3 100 98 | 7 Other SVOCs detected Acenaphthylene Chromium * Acridine ** -- 62 1 -- 72 1 Benz[a]anthracene 50 54 4 Benzo[a]pyrene 100 100 | 7 100 99 | 3 Benzo[b]fluoranthene ** 100 100 7 Benzo[ghi]perylene ** | Benzo[k]fluoranthene ** Copper * Butylbenzylphthalate ** -- 100 1 -- 100 1 Chrysene 100 100 4 p-Cresol ** 100 100 | 7 100 99 3 Di-n-butylphthalate ** 100 100 | 7 Di-n-octylphthalate ** | Dibenz[a,h]anthracene Lead * Diethylphthalate ** -- 11 1 -- 41 1 1,2-Dimethylnaphthalene ** 50 41 4 1,6-Dimethylnaphthalene ** 100 100 | 7 100 100 | 3 Dimethylphthalate ** 100 99 7 2-Ethylnaphthalene ** | Indeno[1,2,3-cd]pyrene ** Mercury * Isoquinoline ** -- 71 1 -- 59 1 1-Methyl-9H-fluorene ** 75 80 4 2-Methylanthracene ** 100 82 | 7 4,5-Methylenephenanthrene ** 100 97 | 3 100 93 7 1-Methylphenanthrene ** | 1-Methylpyrene ** Nickel * ** Naphthalene -- 42 1 -- 44 1 Phenanthridine ** 0 50 4 Quinoline ** 100 100 7 2,3,6-Trimethylnaphthalene ** 100 100 3 100 100 7 SVOCs not detected C8-Alkylphenol ** Selenium * -- 99 1 Azobenzene ** -- 100 1 Benzo[c]cinnoline ** 100 99 4 2,2-Biquinoline ** 100 100 | 7 100 100 | 3 4-Bromophenyl-phenylether ** 100 100 | 7 4-Chloro-3-methylphenol ** bis(2-Chloroethoxy)methane ** 0.01 0.1 1 10 100 1,000 10,000 2-Chloronaphthalene ** 2-Chlorophenol ** CONCENTRATION, IN MICROGRAMS PER GRAM (Fish tissue is wet weight, bed sediment is dry weight)

Water-Quality Data in a National Context 31

Study-unit frequency of detection, in percent National frequency of detection, in percent Study-unit sample size

Zinc * -- 100 1 -- 100 1 100 100 4 100 100 | 7 100 99 | 3 100 100 | 7

0.01 0.1 1 10 100 1,000 10,000

CONCENTRATION, IN MICROGRAMS PER GRAM (Fish tissue is wet weight, bed sediment is dry weight)

BIOLOGICAL INDICATORS Higher national scores suggest habitat disturbance, water-quality degradation, or naturally harsh conditions. The status of algae, invertebrates (insects, worms, and clams), and fish provide a record of water-quality and stream conditions that water- chemistry indicators may not reveal. Algal status focuses on the changes in the percentage of certain algae in response to increasing siltation, and it often correlates with higher nutrient concentrations in some regions. Invertebrate status averages 11 metrics that summarize changes in richness, tolerance, trophic conditions, and dominance associated with water-quality degradation. Fish status sums the scores of four fish metrics (percent tolerant, omnivorous, non-native individuals, and percent individuals with external anomalies) that increase in association with water-quality degradation

Biological indicator value, Santee River Basin and coastal drainages, by land use, 1995–98 Biological status assessed at a site

National ranges of biological indicators, in 16 NAWQA Study Units, 1994–98 Streams in undeveloped areas Streams in agricultural areas Streams in urban areas Streams in mixed-land-use areas 75th percentile 25th percentile

Algal status indicator Undeveloped Agricultural Urban Mixed

Invertebrate status indicator Undeveloped Agricultural Urban Mixed

0 10 20 30 40 50 60 70 80 90 100

Fish status indicator Undeveloped Agricultural Urban Mixed

0 5 101520

32 Water Quality in the Santee River Basin and Coastal Drainages A COORDINATED EFFORT

Coordination with agencies and organizations in the Santee River Basin and coastal drainages was integral to the success of this water-quality assessment. We thank those who served as members of our liaison committee.

Federal Agencies Gaston County Cooperative Extension Service National Park Service, Congaree Swamp National Greenville County Soil and Water Conservation Monument District Natural Resources Conservation Service Western Piedmont Council of Governments U.S. Army Corps of Engineers U.S. Fish and Wildlife Service Universities U.S. Forest Service Columbia College South Carolina State University State Agencies University of North Carolina at Charlotte North Carolina Department of Environment and University of South Carolina Natural Resources Ocean and Coastal Resource Management Other public and private organizations South Carolina Department of Health and Environ- Catawba Nation mental Control Clean Water Fund of North Carolina South Carolina Department of Natural Resources Duke Energy South Carolina Forestry Commission National Audubon Society South Carolina Geological Survey South Carolina Electric and Gas Company South Carolina Sea Grant Consortium South Carolina Rural Water Association South Carolina Water Resources Research Institute

Local Agencies Catawba Regional Planning Council Charlotte-Mecklenburg Utility Department

We thank the following individuals for contributing to this effort.

Barbara Kleiss, Ted Campbell, and Sandra Cooper (USGS); Barry Beasley (South Carolina Department of Natural Resources); and Oscar Penegar (Environmental Advocate) for reviewing the report. Jeannie Eidson (South Carolina Department of Environmental Control) for providing support and data for geo- graphic information systems. Larry Bradham (South Carolina Well Drillers Association) for assisting in locating wells for sampling. Gary Taylor and Ralph Willoughby (South Carolina Geological Survey) for assisting in drilling wells. The numerous property owners who allowed the USGS to install monitoring wells or sample existing wells on their property. Ben Abercrombie, Boyce Blanks, Wade Bryant, Kristen Hein, Cliff Hupp, Robert Kelley, Donald Leary, Krystal Lynn, Brent Means, Larry Puckett, Whitney Stringfield, Robert Thorn, and Carlton Wood for providing invaluable technical and field support for the study. Dick Christie (South Carolina Department of Natural Resources), Ginny Lindsey (North Carolina Clean Water Fund), and Charlie Zemp (South Carolina Department of Natural Resources) for providing guided tours of parts of the Santee Basin.

This report is dedicated to the memory of Don Leary; his quiet strength, hard work, and good humor helped make this study a success. NAWQA National Water-Quality Assessment (NAWQA) Program Santee River Basin and Coastal Drainages

Hughes and others— W

ater Quality in the Santee River Basin and Coastal Drainages

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