Support for Integrated Ecosystem Assessments of 

NOAA’s National Estuarine Research Reserves 

System (NERRS), Volume II: 

Assessment of Ecological Condition and Stressor 

Impacts in Subtidal Waters of the North Carolina 

NERRS 

NOAA Technical Memorandum NOS NCCOS 83 

NC 

NERRS 

Sapelo Island 

ACE Basin 

N. Inlet-Winyah Bay 
This report has been reviewed by the National Ocean Service of the National 

Oceanic and Atmospheric Administration (NOAA) and approved for publication. 

Mention of trade names or commercial products does not constitute endorsement 

or recommendation for their use by the United States government. 

Citation for this Report 

Cooksey, C., J. Hyland, E. Wirth, W.L. Balthis, M. Fulton, D.Whitall and S. White. 2008. 

Support for Integrated Ecosystem Assessments of NOAA’s National Estuarine Research 

Reserves System (NERRS), Volume II: Assessment of Ecological Condition and Stressor 

Impacts in Subtidal Waters of the North Carolina NERRS. NOAA Technical Memorandum NOS 

NCCOS 83. NOAA Center for Coastal Environmental Health and Biomolecular Research, 

Charleston, SC.
Support for Integrated Ecosystem Assessments of NOAA’s National 

Estuarine Research Reserves System (NERRS), Volume II: 

Assessment of Ecological Condition and Stressor Impacts in 

Subtidal Waters of the North Carolina NERRS

Cynthia Cookseya, Jeff Hylanda, Ed Wirtha, W. Leonard Balthisa, Mike Fultona, David Whitallb, 

and Susan Whitec

a

NOAA, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson 

Road, Charleston, S C, 29412-9110, USA 

b

NOAA, Center for Coastal Monitoring and Assessment, 1305 East-West Highway, Silver 

Spring, MD, 20910, USA 

c

NOAA, Center for Human Health Risk, Hollings Marine Laboratory, 219 Fort Johnson Road, 

Charleston, SC, 29412-9110, USA 

August 2008 

NOAA Technical Memorandum NOS NCCOS 83

United States Department of National Oceanic and National Ocean Service 

Commerce Atmospheric Administration 

Carlos M. Gutierrez Conrad C. Lautenbacher, Jr. John (Jack) H. Dunnigan 

Secretary Administrator Assistant 

i

Table of Contents 

Table of Contents............................................................................................................................. i

List of Tables .................................................................................................................................. ii

List of Figures................................................................................................................................ iv

List of Appendices .......................................................................................................................... v

Abstract.......................................................................................................................................... vi

1. Introduction................................................................................................................................. 1

2. Methods....................................................................................................................................... 3

2.1 Sampling Design and Field Collection ............................................................................. 3 

2.2 Water Quality Analysis..................................................................................................... 5 

2.3 Chemical Contaminant Analysis....................................................................................... 6 

2.4 Sediment toxicity testing................................................................................................... 7 

2.5 Benthic Community Analysis........................................................................................... 7 

2.6 Data Analysis.................................................................................................................... 9

3. Results and Discussion ............................................................................................................. 13

3.1 Water Quality.................................................................................................................. 13 

3.2 Sediment Quality ............................................................................................................ 21 

3.3 Biological Condition....................................................................................................... 24 

3.4 Overall Ecological Condition and Human Factors ........................................................ 39

4.0 Overall Project Summary and Conclusions ............................................................................ 43

4.1 Summary Points from Volume I: Assessing Impacts of Coastal Development on the 

Ecology and Human Well-Being of Tidal Creek Ecosystems (from Sanger et al. 2008). ... 43 

4.2 Summary Points from Volume II: Assessing Ecological Condition and Stressor Impacts 

in Subtidal Waters of the North Carolina NERRS (Present Volume) .................................. 44 

4.3 Concluding Remarks on Coastal Management Applications and Opportunities............ 44

5.0 References............................................................................................................................... 46 
ii

List of Tables 

Table 1. Thresholds used for classifying samples relative to various environmental indicators... 8

Table 2. ERM and ERL guidance values in sediments (Long et al. 1995). ................................. 11

Table 3. Risk-based EPA advisory guidelines for recreational fishers (US EPA 2004)............. 12

Table 4. Comparison of selected water and sediment characteristics among the four NC 

NERRS. ......................................................................................................................... 16

Table 5. Number of stations (by reserve) and percent area of overall NC NERRS exhibiting 

designated ranges in selected environmental variables. CB=Currituck Banks (n=4), 

RC=Rachel Carson (n=9), MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5).

....................................................................................................................................... 17

Table 6. Number of stations by reserve and percent area within each reserve with contaminants 

in sediment that exceeded corresponding ERL and ERM Sediment Quality Guidelines 

(SQG) values (μg/g dry mass; Long et al. 1995). CB=Currituck Banks (n=4), 

RC=Rachel Carson (n=9), MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5). 

....................................................................................................................................... 23

Table 7. Summary of major taxonomic groups of benthic infauna and corresponding numbers of 

identifiable taxa in samples from NC NERRS.............................................................. 27

Table 8. Comparison of selected benthic characteristics among the NC NERRS. ...................... 29

Table 9. Fifty most abundant benthic taxa at NC NERRS (listed in decreasing order of 

abundance among all samples combined). Mean density (m-2) and frequency of 

occurrence (% of samples from corresponding NERRS reserves) are listed for each of 

the four NERRS and all four combined. CB=Currituck Banks (12 grabs), RC=Rachel 

Carson (27 grabs), MI=Masonboro Island (36 grabs), and ZI=Zeke’s Island (15 grabs). 

Letters in parentheses refer to major taxonomic group: P = Polychaeta, O = 

Oligochaeta, B = Bivalva, G = Gastropoda, C = Crustacea, In = Insecta, and N = 

Nemertea. ...................................................................................................................... 30

Table 10. Comparison of measured concentrations of inorganic arsenic in fish tissues (μg/g wet 

weight) to corresponding cancer and noncancer health endpoints, based on 

consumption of four 8-ounce meals per months (US EPA 2000). CB=Currituck Banks, 

RC=Rachel Carson, MI=Masonboro Island, ZI=Zeke’s Island. ................................... 33

Table 11. Summary of sediment quality based on combined measures of sediment 

contamination, sediment toxicity, and condition of benthic communities.................... 36

Table 12. Evaluation of benthic condition in relation to various possible stressers. .................. 37 
iii

Table 13. Comparison of fish tissues contaminant levels to corresponding sediment 

contaminants at station with tissue contaminant values above human health endpoints.

....................................................................................................................................... 38

Table 14. Estimates of overall ecological condition at NC NERRS based on combined 

indicators of water quality, sediment quality, and biological condition (note: fish tissue 

contaminant data are not included in these calculation of % area, since they represent 

only a portion of the total stations)................................................................................ 42 
iv

List of Figures 

Figure 1. Map of study area, NC NERRS station locations............................................1 

Figure 2. Station locations within each of the NC NERRS: Currituck Banks (A), Rachel Carson 

(B), Masonboro Island (C), and Zeke’s Island (D). Sampling stations are indicated by 

yellow circles and labeled with the site names.................................................3 

Figure 3. Box and whisker plots of selected water and sediment characteristics among the four 

NC NERRS. Boxes=interquartile range, horizontal lines=median, whisker 

endpoints=10th and 90th percentile. CB=Currituck Banks (n=4), RC=Rachel Carson 

(n=9), MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5).......................15 

Figure 4. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

dissolved oxygen (DO, mg/L) in bottom waters.............................................18 

Figure 5. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

(A) dissolved inorganic nitrogen (DIN, mg/L), (B) dissolved inorganic phosphorus 

(DIP, mg/L), and (C) chlorophyll a (CHLa, μg/L) in surface waters......................20 

Figure 6. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

total organic carbon (TOC, mg/g) in sediments...............................................21 

Figure 7. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

chemical contamination in sediments..........................................................23 

Figure 8. Relative compositions of major benthic taxonomic groups at NC NERRS. Data based 

on 3 replicate grabs (0.04m2) at each of 30 stations (Currituck Banks=4, Rachel 

Carson=9, Masonboro Island=12, Zeke’s Island=5). (A) % composition by abundance 

(total # individuals=8908), (B) % composition by taxa (total # taxa=310)...............26 

Figure 9. Box and wisker plots of benthic variables (mean abundance, mean H′, mean number of 

taxa, benthic index of biotic integrity [B-IBI]) among the four NC NERRS. 

Boxes=interquartile range, horizontal lines=median, whisker endpoints=10th and 90th

percentile...........................................................................................28 

Figure 10. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

benthic condition based on benthic index scores (B-IBI)....................................28 

Figure 11. Summary of sediment quality based on combined measures of benthic condition 

(degraded = B-IBI < 3), sediment toxicity (significant Microtox toxicity), and sediment 

contamination (mean ERM-Q > 0.058 or ≥ 1 ERM value exceeded)......................39 
v

List of Appendices 

Appendix A. Locations, depths, and water and sediment characteristics of 30 stations sampled in 

NC NERRS in September 2006. ............................................................................ 53

Appendix B. Summary by station of nutrient and chlorophyll concentrations in surface waters at 

30 stations sampled in NC NERRS in September 2006......................................... 54

Appendix C. Summary of sediment contaminant concentrations (dry mass) by analyte at 30 NC 

NERRS stations. Concentrations that were reported below method detection limits 

(<MDL) were assigned a value of zero for data analysis purposes........................ 55

Appendix D. Summary by station of mean ERM quotients and the number of contaminants that 

exceeded the corresponding ERL or ERM values (from Long et al., 1995) at 30 

NC NERRS stations. .............................................................................................. 60

Appendix E. Summary by station of Microtox toxicity tests conducted in sediments from 30 NC 

NERRS stations. Stations were determined to be toxic if %EC50 was <0.5 and the 

silt-clay content was <20%, or if the %EC50 was <0.2 and the silt-clay content 

was >20%. .............................................................................................................. 61

Appendix F. Summary by station of benthic macroinfaunal (> 0.5mm) characteristics at 30 

stations sampled in NC NERRS in September 2006. Three replicate benthic grabs 

(0.04m2 each) were taken at each station. .............................................................. 62

Appendix G. Summary of fish tissue contaminant concentrations (wet mass) by analyte and fish 

species at NC NERRS. Concentrations that were reported below detection limits 

(<MDL) were assigned a value of zero for data analysis purposes........................ 63 

 
vi

Abstract 

A study was conducted to assess the status of ecological condition and potential human-health 

risks in subtidal estuarine waters throughout the North Carolina National Estuarine Research 

Reserve System (NERRS) (Currituck Sound, Rachel Carson, Masonboro Island, and Zeke’s 

Island). Field work was conducted in September 2006 and incorporated multiple indicators of 

ecosystem condition including measures of water quality (dissolved oxygen, salinity, 

temperature, pH, nutrients and chlorophyll, suspended solids), sediment quality (granulometry, 

organic matter content, chemical contaminant concentrations), biological condition (diversity 

and abundances of benthic fauna, fish contaminant levels and pathologies), and human 

dimensions (fish-tissue contaminant levels relative to human-health consumption limits, various 

aesthetic properties). A probabilistic sampling design permitted statistical estimation of the 

spatial extent of degraded versus non-degraded condition across these estuaries relative to 

specified threshold levels of the various indicators (where possible). With some exceptions, the 

status of these reserves appeared to be in relatively good to fair ecological condition overall, with 

the majority of the area (about 54%) having various water quality, sediment quality, and 

biological (benthic) condition indicators rated in the healthy to intermediate range of 

corresponding guideline thresholds. Only three stations, representing 10.5% of the area, had one 

or more of these indicators rated as poor/degraded in all three categories. While such a 

conclusion is encouraging from a coastal management perspective, it should be viewed with 

some caution. For example, although co-occurrences of adverse biological and abiotic 

environmental conditions were limited, at least one indicator of ecological condition rated in the 

poor/degraded range was observed over a broader area (35.5%) represented by 11 of the 30 

stations sampled. In addition, the fish-tissue contaminant data were not included in these overall 

spatial estimates; however, the majority of samples (77% of fish that were analyzed, from 79%, 

of stations where fish were caught) contained inorganic arsenic above the consumption limits for 

human cancer risks, though most likely derived from natural sources. Similarly, aesthetic 

indicators are not reflected in these spatial estimates of ecological condition, though there was 

evidence of noxious odors in sediments at many of the stations. Such symptoms reflect a 

growing realization that North Carolina estuaries are under multiple pressures from a variety of 

natural and human influences. These data also suggest that, while the current status of overall 

ecological condition appears to be good to fair, long-term monitoring is warranted to track 

potential changes in the future. This study establishes an important baseline of overall ecological 

condition within NC NERRS that can be used to evaluate any such future changes and to trigger 

appropriate management actions in this rapidly evolving coastal environment. 

Key Words: North Carolina NERRS, southeastern estuaries, ecological condition, benthic 

communities, sediment and tissue contaminants, Integrated Ecosystem Assessments 
1

1. Introduction 

Under the FY05-09 Strategic Plan of NOAA’s National Centers for Coastal Ocean Science 

(NCCOS 2004), NCCOS is prompted to produce baseline assessments of ecological resources 

and to quantify impacts of ecosystem stressors in various NOAA protected areas, including 

National Estuarine Research Reserve System (NERRS) locations. The NERRS is an especially 

important network of NOAA protected areas characterized by diverse habitats and living 

resources, multiple human uses, and resultant high ecological and societal value. An integrated 

system-wide approach for monitoring and assessing ecological condition of NERRS resources 

and potential threats from multiple stressors currently does not exist (except for some waterquality parameters). The purpose of the present effort was to work in partnership with the 

NERRS program to assess current status of ecological condition and human-health risks 

throughout NERRS, beginning with GA and NC reserves, and to provide this information as a 

framework for forecasting future changes due to natural or human-induced disturbances. This 

work also is intended to complement system-wide water-quality monitoring (SWMP) and other 

site-specific research activities currently underway in the NERRS program. 

Figure 1. Map of study area, NC NERRS station locations. 
2

This NERRS-NCCOS partnership resulted in solid contributions by NERRS staff in planning, 

field support and logistics, and data interpretation. In addition, local information helped in the 

identification of sampling sites and provided insight into nearby watershed influences on water 

quality (i.e. land use change and development), improving interpretation of watershed and 

historical data. NC NERRS staff also facilitated access to sampling locations. 

There are two complementary components of this project: (1) a tidal-creek, sentinel habitat 

study to develop a framework for evaluating impacts of land-use and associated stressors on tidal 

creeks; and (2) a probabilistic monitoring component to assess the spatial extent of ecological 

condition throughout sub-tidal estuarine waters, based on the status of various measured 

ecological indicators relative to specific management thresholds. Field work for both 

components was conducted in summer 2006 and incorporated multiple indicators of ecological 

condition including basic habitat characteristics (dissolved oxygen, salinity, temperature, pH, 

depth, sediment granulometry and organic matter content, levels of nutrients and chlorophyll in 

the water column), chemical contaminants in sediments and biota (metals, PAHs, PCBs, 

pesticides, and PBDEs), and diversity and abundances of benthic fauna. The tidal-creek 

component focused on NERRS at Sapelo Island, GA and Masonboro Island, NC and is being 

integrated with results of prior/ongoing tidal-creek work in SC. Results of the tidal-creek 

component are discussed in the companion Volume I of this report. The present Volume II 

focuses on results of the sub-tidal probabilistic component conducted throughout all four NERRS 

locations in NC: Currituck Sound, Rachel Carson, Masonboro Island, and Zeke’s Island (Figure 

1). 

Together, the two project components are intended to provide a demonstration of the utility of 

the complementary assessment tools, one serving as a sentinel of environmental signals in areas 

of estuaries where signals are likely to occur, and the other providing a means for assessing the 

spatial extent of condition throughout a targeted resource category (i.e., sub-tidal estuarine 

waters of a reserve) and how the relative proportions of healthy vs. degraded areas may be 

changing with time. This pilot project is providing new information on the status of ecological 

condition and human-health risks in the NC and GA NERRS. The results may also serve as a 

useful framework of assessment strategies that could be applied systematically across other 

reserves to support national comparisons. 
3

2. Methods 

2.1 Sampling Design and Field Collection 

A total of 30 stations were sampled in the North Carolina National Estuarine Research Reserve 

System (NC NERRS). The four component NC NERRS reserves (Currituck Sound, Rachel 

Carson, Masonboro Island, and Zeke’s Island) are located across a wide latitudinal range and 

encompass a variety of physical environments. Therefore, stations were distributed 

proportionally among the subtidal areas of the component NC NERRS sites, as follows, using a 

stratified random design (Figures 1 and 2): 

Figure 2. Station locations within each of the NC NERRS: Currituck Banks (A), Rachel Carson 

(B), Masonboro Island (C), and Zeke’s Island (D). Sampling stations are indicated by yellow 

circles and labeled with the site names.
4

Currituck Banks (4 stations) 

Rachel Carson (9 stations) 

Masonboro Island (12 stations) 

Zeke’s Island (5 stations) 

Geographic delineations of these areas were derived from GIS shapefiles provided by the NC 

NERRS office, based on a habitat classification scheme which was recently adopted to 

consistently describe ecosystems throughout the Reserve System and at various levels of detail 

(Kutcher et al. 2005). The NERRS Habitat Classification scheme is a modified combination of 

classification schemes established for the U.S. Geological Survey (Anderson et al. 1976), U.S. 

Fish and Wildlife Service (Cowardin et al. 1979), and NOAA Coastal Change Analysis Program 

(C-CAP 2004). The NERRS Habitat Classification scheme uses a nested hierarchical structure 

to describe habitat and land cover conditions at 5 levels of detail: System, Subsystem, Class, 

Subclass, and Descriptors. Each habitat category is assigned a unique text label and numerical 

code for each hierarchical level. This allows the classified data to be analyzed efficiently and 

summarized at any of the 5 levels. 

The NC NERRS office conducted a pilot project at the Zeke’s Island component to evaluate the 

NERRS Habitat Classification scheme and develop standardized methods for consistent 

application of the scheme for the four NC NERRS components. Habitat analyses and area 

calculations were conducted using ESRI GIS software. Products resulting from the NC NERRS 

habitat classification effort include geo-referenced digital shapefiles with polygons that delineate 

habitat subclasses for each of the four NC NERRS components. Attribute tables of the 

shapefiles include a text label and numerical code for the four highest levels of the classification 

scheme. Attribute data for Descriptors (level 5) will be added as time and priorities allow. Areal 

coverage in acres was calculated and summarized for each habitat sub-class for each of the four 

NC NERRS components. 

For this study, the sub-tidal portions of each NC NERRS reserve, the survey area, were extracted 

as polygons. Each of the four NC NERRS is considered an individual stratum. Within each 

stratum, a set of random locations was generated using the Random Point Generator extension to 

ArcView (Jenness 2003). Points were generated with a minimum separation distance of 2 km 

within each component NC NERRS. The number of sites in each reserve was proportional to the 

total subtidal area of the four reserves combined (i.e., selection weighted by size). 

All field work was conducted in September 2006 from small trailerable boats. Sampling dates 

for the 30 stations were as follows: four stations at Currituck Banks on September 7, nine 

stations at Rachel Carson from 9 – 11 September, 12 stations at Masonboro Island from 12 – 14 

September, and five stations at Zeke’s Island on September 15. Coordinates for each station are 

given in Appendix A. 

At each station, synoptic sampling of a variety of ecological indicators was conducted — 

including general habitat characteristics, multiple stressor levels, toxicity, and biological 

responses — to support “weight-of-evidence” assessments of condition and examination of 

potential associations between presence of stressors and potential bioeffects. Salinity (ppt), pH, 

temperature (o

C), dissolved oxygen (mg L-1), and water depth (m) were measured at 
5

approximately 1 m off the bottom using a Hydrolab, Minisonde 4, water-quality data logger. 

Discrete samples (1 L) of near-surface water (~ 0.5 m below surface) also were collected at each 

station for the analysis of nutrients, total suspended solids (TSS), and chlorophyll a. 

Sediment samples for analysis of chemical contaminants, total organic carbon (TOC), grain-size, 

sublethal toxicity (Microtox assay), and benthic community characteristics were collected at each 

station using a 0.04-m2 Young grab sampler. Grabs were collected to a maximum depth of 10 

cm and rejected if < 5 cm or if there was other evidence of sampling disturbance (e.g., major 

slumping, debris caught in jaws). Surficial sediments (upper 2-3 cm) were collected and 

composited from multiple grabs to provide sufficient material (~ 8 L) for the TOC, grain-size, 

Microtox, and contaminant analyses. Subsamples of the composited material were removed and 

placed into appropriate sample containers. As part of the QA/QC process, steps were taken to 

minimize spurious contamination such as between-station rinses of the grab and sampling 

utensils with acetone and site water. Sediments collected for contaminant analyses were 

maintained on ice throughout sampling and shipment, stored frozen (- 40 C) once transferred to 

the laboratory, and analyzed within 12 months of receipt. Sediments collected for toxicity 

testing were maintained on ice throughout sampling and shipment, kept under refrigeration (~ 4 

C) once in the laboratory, and analyzed within 30 days of receipt. Three separate Young grabs 

also were collected at each station and processed as individual replicate samples for the analysis 

of benthic macroinfauna. Contents of the grabs were sieved in the field with a 0.5-mm mesh 

screen. Material remaining on the screen was fixed in 10% buffered formalin with rose bengal 

and transferred to the laboratory for further processing. 

Sampling of fish for chemical contaminant analysis was attempted at each station using a baited 

hook and line. A total of 22 fish collected among four species, from 14 of the 30 stations, were 

selected for analysis as follows: 

 3 white perch (Morone americanus) from two stations at Currituck Banks; 

 11 Atlantic croaker (Micropogonias undulatus): one fish from Currituck Banks, two fish 

from one station at Rachel Carson, one fish each from three stations at Masonboro Island, 

and five fish from one station at Zeke’s Island; 

 2 spot (Leiostomus xanthurus): one fish each from Currituck Bank and Zeke’s Island; 

and 

 6 pigfish (Orthopristis chrysoptera): one fish each from five stations at Rachel Carson 

and one station at Masonboro Island. 

Fish samples were maintained on ice throughout sampling and shipment, stored frozen (- 40 C) 

once transferred to the laboratory, and analyzed within 12 months of receipt. Fish muscle was 

used for tissue chemical contaminant analysis. 

2.2 Water Quality Analysis 

Preliminary processing of water samples for nutrients, chlorophyll, and TSS was conducted 

onshore at the end of each sampling day. A portion of the water (~0.5 L) from each station was 

vacuum-filtered using Filterware microfiltration glassware and a Whatman GF/F 47mm filter. 
6

The filtered water sample was then transferred to a 120 mL polypropylene bottle, frozen (< -

20°C), and analyzed within 30 days for dissolved nutrients including ammonium (NH4

+

), 

nitrate/nitrite (NO2/3), orthophosphate (PO4

3-), silicate (Si), total dissolved phosphorus (TDP), 

and total dissolved nitrogen (TDN)). The filter was folded and wrapped in a foil pouch, frozen, 

and analyzed within 30 days for chlorophyll a (CHLa) and phaeopigments (PHAEO). Whole 

water samples were frozen in 60 mL polypropylene bottles and later analyzed for total nitrogen 

(TN) and total phosphorus (TP). Remaining water was used to measure TSS within 7 days of 

collection. 

Water chemistry was measured at the Chesapeake Biological Laboratory (Solomons, Maryland) 

using established laboratory methods for the analysis of NH4

+

 (method 804-86T, Technicon 

1986a), NO2/3 (method 158-71, Technicon 1977), PO4

3- (method 155-71W, Technicon 1973), 

and Si (method 811-86T, Technicon 1986b). TN, TP, TDN, and TDP concentrations were 

determined by a persulfate digestion method (Valderrama 1981). The Welschmeyer method 

(Welschmeyer 1994) was used to determine both CHL and PHAEO. TSS was analyzed using a 

photometric method on a HACH DR/2500 TSS analyzer (method 8006, Hach 2003). 

2.3 Chemical Contaminant Analysis 

2.3.1 Laboratory Sample Preparation 

Sediment samples were kept frozen at approximately - 40 oC until analysis could proceed. To 

thaw, samples were left in closed containers in a + 4 oC cooler for approximately 24 hours. 

Samples were thoroughly homogenized by hand prior to any sample extraction. Fish tissue 

samples were frozen upon receipt in the laboratory and stored at - 40 oC until analysis. Fish were 

removed from the freezer and stored overnight at 4 oC and allowed to partially thaw. The fish 

were filleted (skin on) and well homogenized using a ProScientific homogenizer in 500 mL 

Teflon containers. The homogenized tissue sample was split into an organic (pre-cleaned glass 

container) and inorganic (pre-cleaned polypropylene container) and stored at - 40 oC until 

extraction or digestion. 

A percent dry-weight determination was made gravimetrically on an aliquot of the wet sediment 

and tissues. 

2.3.2 Inorganic Sample Digestion and Analysis 

Dried sediment was ground with a mortar and pestle and transferred to a 20 mL plastic screw-top 

container. A 0.25 g sub-sample of the ground material was transferred to a Teflon-lined 

digestion vessel and digested in 5 mL of concentrated nitric acid using microwave digestion. 

The sample was brought to a fixed volume of 50 mL in a volumetric flask with deionized water 

and stored in a 50 mL polypropylene centrifuge tube until instrumental analysis of Li, Be, Al, Fe, 

Mg, Ni, Cu, Zn, Cd, and Ag. A second 0.25 g sub-sample was transferred to a Teflon-lined 

digestion vessel and digested in 5 mL of concentrated nitric acid and 1 mL of concentrated 

hydrofluoric acid in a microwave digestion unit. The sample was then evaporated on a hotplate 

at 225 °C to near dryness and 1 mL of nitric acid was added. The sample was brought to a fixed 

volume of 50 mL in a volumetric flask with deionized water and stored in a 50 mL 
7

polypropylene centrifuge tube until instrumental analysis for V, Cr, Co, As, Sn, Sb, Ba, Tl, Pb, 

and U. Selenium was analyzed by hotplate digestion using a 0.25 g sub-sample and 5 mL of 

concentrated nitric acid. Each sample was brought to a fixed volume of 50 mL in a volumetric 

flask with deionized water and stored in a 50 mL polypropylene centrifuge tube until 

instrumental analysis. Additionally, two to three grams wet tissue were microwave digested in 

Teflon-lined digestion vessels using 10 mL of concentrated nitric acid along with 2 mL of 

hydrogen peroxide. Digested samples were brought to a fixed volume with deionized water in 

graduated polypropylene centrifuge tubes and stored until analysis. Finally, a separate inorganic 

aliquot was used for mercury analysis. Approximately 0.5 g of wet sediment or tissue was 

analyzed on a Milestone DMA-80 Direct Mercury Analyzer. 

All remaining elemental analysis was performed using an Inductively Coupled Plasma Mass 

Spectrometry (ICP-MS) except for silver, which was determined using Graphite Furnace Atomic 

Absorption (GFAA) spectroscopy. Data quality was controlled by using a series of blanks, 

spiked solutions, and standard reference materials including NRC MESS-3 (Marine Sediments) 

and NIST 1566b (freeze dried mussel tissue). 

2.3.3 Organic Extraction and Analysis 

An aliquot (10 g sediment or 5 g tissue wet weight) was extracted with anhydrous sodium sulfate 

using Accelerated Solvent Extraction (ASE) in either 1:1 methylene chloride:acetone (for 

sediments) or 100% dichlormethane (for tissues) (Schantz 1997). Following extraction, samples 

were dried and cleaned using Gel Permeation Chromatography and Solid Phase Extraction to 

remove lipids and then solvent-exchanged into hexane for analysis. Samples were analyzed for 

PAHs, PBDEs, PCBs (by congener), and a suite of chlorinated pesticides using appropriate 

GC/MS technology. Data quality was ensured by using a series of spiked blanks, reagent blanks, 

and appropriate standard reference materials including NIST 1944 (sediments) and NIST 1566b 

(muscle tissue). 

2.4 Sediment toxicity testing 

Microtox assays were conducted using the standardized solid-phase test protocols (Microbics 

Corporation 1992) and a Microtox Model 500 analyzer (Strategic Diagnostics Inc., CA). In this 

assay, sediment was homogenized and a 7.0 – 7.1 g sediment sample was used to make a series 

of sediment dilutions with 3.5% NaCl diluent, which were incubated for 10 minutes at 15 oC. 

Luminescent bacteria (Vibrio fisheri) were then added to the test concentrations. The liquid 

phase was filtered from the sediment phase and bacterial post-exposure light output was then 

measured using Microtox Omni Software. An EC50 value (the sediment concentration that 

reduces light output by 50% relative to the controls) was calculated for each sample. Triplicate 

samples were analyzed simultaneously. Sediment samples were classified as either toxic or nontoxic using criteria developed by Ringwood and Keppler (1998). 

2.5 Benthic Community Analysis 

Once in the laboratory, samples were transferred from formalin to 70% ethanol. Macroinfaunal 

invertebrates were sorted from the sample debris under a dissecting microscope and identified to 
8

the lowest practical taxon (usually species). Data quality steps included: (1) tests of ongoing 

sorting proficiency on 10% of samples by independent sorters to assure that  95% of animals in 

each sample were removed by original sorter; (2) use of skilled taxonomists with updated 

standard taxonomic keys and reference collections to perform species identifications; (3) checks 

for potential misidentifications on minimum of 10% of samples by independent qualified 

taxonomists; and (4) appropriate corrective actions to resolve any potential sorting or species 

identification errors. Data were used to compute density (m-2) of total fauna (all species 

combined), densities of numerically dominant species (m-2), numbers of species, H' diversity 

(Shannon and Weaver 1949) derived with base-2 logarithms, and estimates of condition based on 

the Southeastern benthic index of biotic integrity (B-IBI, Van Dolah et al. 1999). Computation 

of the B-IBI was based on the procedures and habitat designations of Van Dolah et al. (1999). 

B-IBI scoring criteria are presented here in Table 1. 

Table 1. Thresholds used for classifying samples relative to various environmental indicators. 

Indicator Threshold Reference 

Water Quality 

Salinity (ppt) < 5 = Oligohaline Carriker 1967 

5 – 18 = Mesohaline 

>18 – 30 = Polyhaline 

> 30 = Euhaline 

DO (mg/L) < 2 = Low (Poor) USEPA 2004; 

 2 – 5 = Moderate (Fair) Diaz and Rosenberg 1995 

 > 5 = High (Good) 

DIN (mg/L) > 0.5 = High (Poor) USEPA 2004 

 0.1 – 0.5 = Moderate (Fair) 

 < 0.1 = Low (Good) 

DIP (mg/L) > 0.05 = High (Poor) USEPA 2004 

 0.01 – 0.05 = Moderate (Fair) 

 < 0.01 = Low (Good) 

CHLa (μg/L) > 20 = High (Poor) USEPA 2004 

 5 – 20 = Moderate (Fair) 

 < 5 = Low (Good) 

Sediment Quality 

Silt-Clay Content (%) > 80 = Mud USEPA 2004 

20 – 80 = Muddy Sand 

< 20 = Sand 

TOC Content (mg/g) > 50 = High (Poor) USEPA 2004 

 20 – 50 = Moderate (Fair) 

 < 20 = Low (Good) 

 

 > 35 = High (Poor) Hyland et al. 2005 
9

Indicator Threshold Reference 

mERM-Q > 0.058 or 

≥ 1 ERM value exceeded = High (Poor); 

mERM-Q > 0.02 – 0.058 or ≥ 5 ERL 

values exceeded = Moderate (Fair); 

Hyland et al. 1999; 

USEPA 2004 

Chemical 

Contamination 

mERM-Q ≤ 0.02 or No ERMs exceeded 

or < 5 ERLs exceeded = Low (Good) 

Individual chemical > ERM Bioeffects likely Long et al. 1995 

contaminant 

concentrations 

< ERL = Bioeffects not likely 

Sediment Toxicity: Silt-Clay ≥ 20%: Toxic if EC50 ≤ 0.2% 

Microtox Silt-Clay < 20%: Toxic if EC50 ≤ 0.5% 

Ringwood et al. 1997; 

Ringwood and Keppler 

1998 

Biological Condition 

B-IBI ≤ 1.5 = Degraded Benthos Van Dolah et al. 1999 

1.5 – 3 = Some Stress 

≥ 3 = Healthy Benthos 

≥ 1 chemical exceeded Human Health 

upper limit = High (Poor) 

USEPA 2000 

≥ 1 chemical within Human Health risk 

range = Moderate (Fair) 

Chemical 

Contaminants in Fish 

Tissues 

All chemicals below Human Health 

lower risk limit = Low (Good) 

2.6 Data Analysis 

A probabilistic, stratified-random, sampling design was used in this study in order to provide a 

basis for making unbiased statistical estimates of the spatial extent of degraded versus nondegraded condition within the NC NERRS, based on the status of various measured ecological 

indicators and corresponding thresholds of interest at component sampling sites (Table 1). A 

similar approach has been applied throughout EPA’s EMAP and related National Coastal 

Assessment (NCA) programs (e.g., USEPA 2001a, 2001b, 2002). Methods for estimating the 

proportion of area of NC NERRS corresponding to specified values of an indicator, and its 

associated variance, are based on published formulae for stratified random sampling designs 

(Cochran 1977, Fulton et al. 2007, Llanso et al. 2005). For every site i in stratum h, yhi takes the 

value 1 when a criterion is met, and 0 otherwise. The estimated proportion and its associated 

variance for stratum h is calculated as 



 h n

i h

hi

hh

n

y yp

1

ˆ (1) 

and 

Table 1 continued. 
10

 

  h n

i h

hhi

hh

n

yy sp

1

2

2

1

)( var( ) . (2) 

The estimated proportion for a given system (combined across L strata) is given as 





L

i

hh yWP

1

ˆ , (3) 

where the weighting factor Wh = Ah/A; Ah is the area of stratum h, and A is the combined area of 

all strata. The variance of (3) is calculated as 





L

h

nSWP hhh

1

22 ) / var( . (4) ˆ

Results of the above type of spatial estimates are presented throughout this report as the percent 

area (± 95% confidence interval) of NC NERRS within specified ranges of a particular indicator. 

Thresholds defining such ranges (see Table 1) include, where possible, those having known 

biological significance (e.g.; dissolved oxygen < 2 mg/L) or that represent other basic 

environmental delineations (e.g.; breakpoints depicting various salinity zones). Additional data 

summaries include box-whisker plots of key distributional properties (e.g., where boxes are 

interquartile ranges, horizontal lines within boxes are medians, and wisker endpoints are 10th and 

90th percentile points) and other basic data tabulations. 

The biological significance of sediment contamination was evaluated by comparing measured 

chemical concentrations in sediments to corresponding Effects Range-Low (ERL) and Effects 

Range-Median (ERM) sediment quality guideline (SQG) values developed by Long et al. (1995) 

and listed here in Table 2. The ERL values are lower-threshold bioeffect limits, below which 

adverse effects on sediment–dwelling organisms are not expected to occur. ERM values 

represent upper-threshold concentrations, above which bioeffects are likely to occur in some 

sediment-dwelling species. Overall sediment contamination from multiple chemicals was 

expressed as the mean ERM quotient (ERM-Q) (Long et al. 1998; Long and MacDonald 1998; 

Hyland et al. 1999), which is the mean of the ratios of individual chemical concentrations in a 

sample relative to corresponding ERM values. Mean ERM-Qs ≤ 0.02 and > 0.058 have been 

associated with a low and high incidence of stress, respectively, in benthic communities of 

southeastern estuaries (Hyland et al 1999). 

The biological significance of fish-tissue contamination was evaluated from a human-health 

perspective using risk-based consumption limits for cancer and non-cancer (chronic systemic 

effects) endpoints derived by USEPA (2000) for a variety of organic and inorganic contaminants 

(Table 3). Concentrations of contaminants measured in fish tissues (filets with skin on) were 

compared to the corresponding endpoints for cancer and chronic health risks associated with the 

consumption of four 8-ounce meals per month for the general adult population. Fish tissue 

contamination data were only available for a subset of stations, therefore, tissue contaminant data 

were not evaluated on a percent areal basis nor were they included in the final estimate of 

ecological condition of NC NERRS (see Table 14). 
11

Table 2. ERM and ERL guidance values in sediments (Long et al. 1995). 

 

Metals (μg/g) ERL ERM 

Arsenic 8.2 70 

Cadmium 1.2 9.6 

Chromium 81 370 

Copper 34 270 

Lead 46.7 218 

Mercury 0.15 0.71 

Silver 1 3.7 

Zinc 150 410 

Organics (ng/g) ERL ERM 

Acenaphthene 16 500 

Acenaphthylene 44 640 

Anthracene 85.3 1100 

Fluorene 19 540 

2-Methyl naphthalene 70 670 

Naphthalene 160 2100 

Phenanthrene 240 1500 

Benzo(a)anthracene 261 1600 

Benzo(a)pyrene 430 1600 

Chrysene 384 2800 

Dibenz(a,h)Anthracene 63.4 260 

Fluoranthene 600 5100 

Pyrene 665 2600 

Total PAHsa

 4020 44800 

4,4-DDE 2.2 27 

Total DDTb

 1.58 46.1 

Total PCBsc

 22.7 180 a without Perylene 

b Total DDTs = 2,4′-DDD + 4,4′-DDD + 2,4′-DDE + 4,4′-DDE + 2,4′-DDT + 4,4′-DDT c Total PCBs: ((Sum of 18 PCB congeners) * 2.19) + 2.19
12

Table 3. Risk-based EPA advisory guidelines for recreational fishers (US EPA, 2004). 

Health Endpoint 

(non-cancer) 

Health Endpoint 

(cancer) 

Metals μg/g Concentration Rangea

 Concentration Rangeb

 Arsenic (inorganic)c 0.35-0.70 0.008–0.016 

 Cadmium 0.35-0.70 

 Mercury (methelmercury)d

 0.12-0.23 

 Selenium 5.9-12.0 

Organics ng/g 

 Chlordane 590-1200 0.03–0.07 

 DDT (total) 59-120 0.035–0.069 

 Dieldrin 59-120 0.00073–0.0015 

 Endosulfan 7000-14000 

 Endrin 350-700 

 Heptachlor Epoxide 15-31 0.0013–0.0026 

 Hexachlorobenzene 940-1900 0.0073–0.015 

 Lindane 350-700 0.009–0.018 

 Mirex 230-470 

 Toxaphene 290-590 0.011–0.021 

 PCB (total) 23-47 0.0059–0.012 

a. Range of concentrations associated with non-cancer health endpoint risk for consumption of four 8-oz meals per 

month. 

b. Range of concentrations associated with cancer health endpoint risk for consumption of four 8-ounce meals per 

month. 

c. Inorganic arsenic, the form considered toxic, estimated as 2% of total arsenic (USEPA 2000). 

d. Because most mercury in fish is present as methyl mercury, USEPA 2000 recommends total mercury be analyzed 

for with the conservative assumption that all mercury is present as methylmercury. 
13

3. Results and Discussion 

3.1 Water Quality 

3.1.1 General Water Characteristics 

Key bottom-water characteristics, as measured during this survey, throughout the four reserves 

(Figure 3, Table 4, Appendix A) can be summarized as follows: (1) relatively shallow water 

depths ranging from 0.7 – 4.3 m and averaging 1.5 m (water depths were not corrected to Mean 

Low Low Water); (2) widely variable salinities ranging from oligohaline to euhaline values of 

2.6 – 36.2 ppt (overall mean of 25.6 ppt); (3) moderate to high DO levels ranging from 4.6 – 9.0 

mg/L and averaging 5.9 mg/L; (4) typical late-summer, southern-temperate temperatures 

ranging from 22.5 – 25.6 °C and averaging 24.3 °C; and (5) slightly basic pH levels ranging 

from 7.3 – 8.7 and averaging 7.8. Mean water-quality variables at each of the individual reserves 

ranged from 1.0 m (Currituck Banks) to 1.8 m (Masonboro Island) for depth, 2.7 ppt (Currituck 

Banks) to 35.0 ppt (Rachel Carson) for salinity, 5.6 mg/L (Masonboro Island) to 7.5 mg/L 

(Currituck Banks) for DO, 24.0 °C (Masonboro Island) to 24.6 °C (Rachel Carson) for 

temperature, and 7.6 (Zeke’s Island) to 7.9 (Currituck Banks) for pH. Currituck Banks was 

characterized by the lowest salinities and highest DO levels of the four reserves. 

DO levels in bottom waters at all stations were well above a reported benthic hypoxic-effectthreshold of about 1.4 mg/L (Diaz and Rosenberg 1995). Only one station at Masonboro Island, 

representing 3.5% (± 6.9%) of the NC NERRS survey area, had a moderate DO concentration 

(4.6 mg/L) below the 5 mg/L upper threshold (Figure 4, Table 5). The majority of the area (96.5 

± 6.9%), represented by 29 of the 30 stations, had DO in the high range (> 5.0 mg/L) considered 

safe for marine life. In contrast, Hyland et al. (2000) reported low-DO conditions over larger 

portions of North Carolina estuaries state-wide, with DO < 2 mg/L in 4% of the area and DO < 5 

mg/L in another 14% of the area. USEPA (2004) also reported a lower incidence of high-DO 

water throughout southeastern estuaries region-wide, with DO > 2 mg/L in 74% of the area, 2-5 

mg/L in 24% of the area, and < 2 mg/L in 2% of the area. 

The amount of total suspended solids (TSS) in the water column has a direct effect on turbidity 

(a measure of water clarity) by causing the attenuation or scattering of light. Generally as TSS 

increases, the water becomes murkier or more turbid. Excessively high turbidity and TSS may 

be harmful to marine life (e.g., by reducing light penetration and photosynthesis, increasing 

biological oxygen demand of high organic content, interfering with normal respiratory and 

feeding activities) and distract from the aesthetic value of a coastal area. TSS in surface waters 

throughout the NC NERRS stations ranged from 6.0 to 24.0 mg/L and averaged 12.0 mg/L 

(Table 4, Appendix A). Mean TSS at each of the four individual reserves ranged from a low of 

8.5 mg/L at Masonboro Island to 17.6 mg/L at Currituck Banks. Fifteen of the 30 stations, 

representing an estimated 50% of the survey area, had TSS concentrations < 10.5 mg/L and 27 

stations, representing about 90% of the area, had concentrations < 18.7 mg/L. These values 

appear to be within a normal range for North Carolina estuaries. For example, unpublished data 

on TSS collected from surface waters of North Carolina estuaries as part of the EPA EMAP 
14

program (1997/98 data from 40 sites, www.epa.gov/emap/nca/) show a range of 0 to 54.5 mg/L 

and mean of 8.7 mg/L. Though we are not aware of any TSS guideline for estuarine receiving 

waters, only one station at Rachel Carson had a TSS concentration (24.0 mg/L) above the State 

of North Carolina’s effluent discharge limit of 20 mg/L for Outstanding Resource Waters 

(NCDENR 2007). 

The State of North Carolina has a turbidity standard for saltwater measured in Nephelometric 

Turbidity Units (i.e., 25 NTU, NCDENR 2007) which is a measure of the amount of light 

scattered due to the presence of suspended particles. NTU levels, usually obtained through use 

of a nephelometric sensor, were not measured in the present study. While there is no simple 

conversion factor to use for relating TSS to NTU, a general rule of thumb reported by Michaud 

(1994) is that 1 mg TSS/L ≈ 1.0 to 1.5 NTUs. If this latter approximation range is applied to the 

TSS concentrations in Appendix A, then it can be estimated that at best case (using the lower 

conversion factor) none of the 30 NC NERRS stations had NTU levels above 25 and that at 

worse case (higher conversion factor) six of the stations, representing 18.6% of the total reserve 

area, had values above 25. Half of these stations were in the Currituck Banks reserve. 
15

Figure 3. Box and whisker plots of selected water and sediment characteristics among the 

four NC NERRS. Boxes=interquartile range, horizontal lines=median, whisker 

endpoints=10th and 90th percentile. CB=Currituck Banks (n=4), RC=Rachel Carson (n=9), 

MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5).
16

Table 4. Comparison of selected water and sediment characteristics among the four NC NERRS. 

 Overall Currituck Banks Rachel Carson Masonboro Island 

Mean Range Mean Range Mean Range Mean Range M

Water:

Depth (m) 1.5 0.7 – 4.3 1.0 1.0 - 1.0 1.6 0.8 - 4.3 1.8 0.7 - 3.8 1DO (mg/L) 5.9 4.6 – 9.0 7.5 5.9 - 9.0 5.8 5.2 - 6.3 5.6 4.6 - 6.3 5Salinity 25.6 2.6 – 36.2 2.7 2.6 - 2.7 35.0 32.8 - 36.1 32.2 19.9 - 36.2 1Temperature (oC) 24.2 22.5 – 25.6 24.1 23.2 - 25.2 24.6 23.3 - 25.6 24 22.5 - 25.3 2pH 7.8 7.3 – 8.7 7.9 7.3 - 8.7 7.8 7.4 - 8.0 7.8 7.6 - 8.0 7

DIN (mg/L) 0.055 0.007 - 0.238 0.018 0.010 - 0.023 0.010 0.007 - 0.015 0.035 0.007 - 0.115 0.DIP (mg/L) 0.015 0.002 - 0.053 0.002 0.002 - 0.003 0.004 0.003 - 0.005 0.012 0.005 - 0.034 0.CHL a (μg/L) 8.57 2.70 - 33.07 31.72 29.45 - 33.07 5.02 3.54 - 7.76 4.2 2.70 - 6.15 6

TSS 12.0 6.0 - 24.0 17.6 13.5 – 20.0 13.1 7.5 – 24.0 8.5 6.0 - 15.5 1

Sediments:

TOC (mg/g) 6.6 0.5 - 37.8 9.6 2.0 - 25.1 2.6 0.5 – 9.0 4 0.5 - 16.7 1Silt-Clay (%) 17.4 0.1 - 72.9 29.0 3.2 - 55.7 11.6 0.1 - 46.4 10.4 0.2 - 44.3 3mean ERM-Q 0.0093 0.0024 - 0.0369 0.0096 0.0036 - 0.0184 0.0062 0.0024 - 0.0143 0.0073 0.0032 - 0.0207 0.0
17

Table 5. Number of stations (by reserve) and percent area of overall NC NERRS exhibiting 

designated ranges in selected environmental variables. CB=Currituck Banks (n=4), RC=Rachel 

Carson (n=9), MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5). 

 Number of Stations % Area Overall 

Indicator* CB RC MI ZI (± 95% C.I.) 

Water: 

Salinity Classification 

Oligohaline (< 5 ppt) 4 0 0 0 11.6 (0) 

Mesohaline (5 – 18 ppt) 0 0 0 5 17.6 (0) 

Polyhaline (>18 – 30 ppt) 0 0 4 0 14.0 (11.7) 

Euhaline (> 30 ppt) 0 9 8 0 56.8 (11.7) 

DO (mg/L) 

< 2 (Poor) 0 0 0 0 0 

2 – 5 (Fair) 0 0 1 0 3.5 (6.9) 

> 5 (Good) 4 9 11 5 96.5 (6.9) 

DIN (mg/L) 

> 0.5 (Poor) 0 0 0 0 0 

0.1 – 0.5 (Fair) 0 0 2 5 24.6 (9.2) 

< 0.1 (Good) 4 9 10 0 75.4 (9.2) 

DIP (mg/L) 

> 0.05 (Poor) 0 0 0 2 7.0 (8.4) 

0.01 – 0.05 (Fair) 0 0 5 3 28.1 (14.9) 

< 0.01 (Good) 4 9 7 0 64.9 (12.2) 

CHL a (μg/L) 

> 20 (Poor) 4 0 0 0 11.5 (0) 

5 – 20 (Fair) 0 4 3 3 33.9 (16.9) 

< 5 (Good) 0 5 9 2 54.6 (16.9) 

Sediments: 

Silt-Clay: 

> 80% (Mud) 0 0 0 0 0 

20 – 80% (Muddy Sands) 3 2 2 3 11.6 (16.1) 

< 20% (Sand) 1 7 10 2 88.4 (16.1) 

TOC (mg/g) 

> 50 (Poor) 0 0 0 0 0 

20 – 50 (Fair) 1 0 0 2 9.9 (10.2) 

< 20 (Good) 3 9 12 3 90.1 (10.2) 

 

> 35 (Poor) 0 0 0 2 7.0 (8.4) 
18

 Number of Stations % Area Overall 

Indicator* CB RC MI ZI (± 95% C.I.) 

Significant Microtox 

Toxicity 

0 2 4 3 31.0 (16.6) 

Chemical Contamination 

High (Poor) 0 0 0 0 0 

Moderate (Fair) 0 0 1 2 10.5 (10.9) 

Low (Good) 4 9 11 3 89.5 (10.9) 

Benthic Condition: 

B-IBI 

≤ 1.5 (Degraded Benthos) 0 0 1 2 10.5 (10.9) 

1.5 – 3 (Some Stress) 1 0 3 0 13.4 (12..2) 

≥ 3 (Healthy Benthos) 3 9 8 3 76.1 (15.5) 

Marine Debris (and other 

aesthetic indicators) present: 

0 0 0 0 0 

* See Table 1 for complete descriptions of threshold values for all indicators. 

Figure 4. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

dissolved oxygen (DO, mg/L) in bottom waters.

Table 5 continued. 
19

3.1.2 Nutrients and Chlorophyll 

Dissolved inorganic nitrogen (DIN) levels in surface waters ranged from 0.0068 – 0.2385 mg/L 

and averaged 0.0552 mg/L (Figure 3, Table 4, Appendix B). Mean DIN at each of the four 

individual reserves ranged from a low of 0.0098 mg/L at Rachel Carson to a high of 0.2156 

mg/L at Zeke’s Island. No part of NC NERRS had high DIN levels (> 0.5 mg/L) indicative of 

high eutrophic potential, while 75.4 ± 9.2% of the area had low “good” levels of DIN (< 0.1 

mg/L) (Figure 5, Table 5). USEPA (2004) reported similarly low levels of DIN during the late 

summer time-frame for southeastern estuaries region-wide, with DIN < 0.1 mg/L in 79% of the 

area, 0.1 – 0.5 mg/L in 21% of the area, and > 0.5 mg/L in < 1% of the area. 

Dissolved inorganic phosphorus (DIP) levels in surface waters ranged from 0.0020 – 0.0532 

mg/L and averaged 0.0146 mg/L (Figure 3, Table 4, Appendix B). Mean DIP at each of the four 

individual reserves ranged from a low of 0.0024 mg/L at Currituck Banks to 0.0492 mg/L at 

Zeke’s Island. An estimated 64.9 ± 12.2% of the overall survey area had low levels of DIP < 

0.01 mg/L; 28.1 ± 14.9% had moderate levels from 0.01 – 0.05 mg/L; and 7.0 ± 8.4% of the 

area, represented by two stations at Zeke’s Island, had DIP in the upper range (> 0.05 mg/L) 

indicative of high eutrophic potential (Figure 5, Table 5). USEPA (2004) reported similar levels 

of DIP during the late summer time-frame for southeastern estuaries region-wide, with DIP < 

0.01 mg/L in 64% of the area, 0.1 – 0.5 mg/L in 24% of the area, and > 0.5 mg/L in 12% of the 

area. 

Chlorophyll a (CHLa) levels in surface waters ranged from 2.70 – 33.07 μg/L and averaged 8.58 

μg/L (Figure 3, Table 4, Appendix B). Mean CHLa at each of the four individual reserves 

ranged from a low of 4.20 μg/L at Masonboro Island to a high of 31.72 μg/L at Currituck Banks. 

An estimated 54.6 ± 16.9% of the overall survey area had low levels of CHLa < 5 μg/L; 33.9 ± 

16.9% had moderate levels from 5 – 20 μg/L; and 11.6 ± 0% of the area, represented by all four 

of the stations at Currituck Banks, had CHLa in excess of the upper 20 μg/L threshold, indicative 

of high eutrophic potential (Figure 5, Table 5). The co-occurrence of relatively low levels of 

DIN and DIP and moderate to high levels of CHLa, as observed here over a sizeable portion of 

the NERRS survey area (Appendix B), reflects a natural process of nutrient reduction due to 

uptake by phytoplankton and resultant chlorophyll production, which is typical of southeastern 

estuaries during the spring to summer period (USEPA 2004). USEPA (2004), however, reported 

CHLa at moderate to high levels over a much broader portion of southeastern estuaries regionwide, with only 18% of the area having values < 5 μg/L, 80% having values from 5 – 20 μg/L, 

and 3% having values > 20 μg/L. 
20

Figure 5. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges of 

(A) dissolved inorganic nitrogen (DIN, mg/L), (B) dissolved inorganic phosphorus (DIP, 

mg/L), and (C) chlorophyll a (CHLa, μg/L) in surface waters.
21

3.2 Sediment Quality 

3.2.1 Grain Size and TOC 

The percentage of silt-clay in sediments ranged from 0.1% to 72.9% and averaged 17.4% 

throughout the four reserves (Table 4, Fig. 3, Appendix A). Mean percent silt-clay at each of the 

individual reserves ranged from a low of 10.4% at Masonboro Island to 35.7% at Zeke’s Island, 

depicting a predominance of sands to intermediate muddy sands throughout much of the area. 

Approximately 88% of the overall survey area had sediments composed of sands (< 20% siltclay) and 12% was composed of intermediate muddy sands (20-80% silt-clay). None of the 

stations were composed of muds (> 80% silt-clay) (Table 5). 

Total organic carbon (TOC) in sediments ranged from 0.5 to 37.8 mg/g and averaged 6.6 mg/g 

throughout the four reserves (Table 4, Fig. 3, Appendix A). Mean TOC at each of the individual 

reserves ranged from a low of 2.6 mg/g at Rachel Carson to 17.9 mg/g at Zeke’s Island. The 

majority of the survey area (90.1%) had relatively low TOC levels of < 20 mg/g, while the 

remaining portion (9.9%) had moderate TOC levels (20 – 50 mg/g; Table 5). None of the survey 

area had high levels of TOC in a range (> 50 mg/g) potentially harmful to benthic fauna (Figure 

6). In comparison, Hyland et al. (2000) 

reported a much larger range of TOC 

values (0.2 – 117.8 mg/g) and a lower 

percentage of area (73%) in the low (< 20 

mg/g) range for North Carolina estuaries 

statewide. The upper and lower thresholds 

of 20 mg/g and 50 mg/g used here for 

evaluating the biological significance of 

sediment TOC content are adopted from 

earlier EPA National Coastal Condition 

Reports (e.g., U.S. EPA 2004). Hyland et 

al. (2005) also identified TOC 

concentrations > 35 mg/g as an upper 

range associated with a high risk of 

degraded benthic condition from multiple 

coastal areas around the world. The 

portion of the present survey area with 

TOC in excess of this slightly more 

conservative threshold also was small (7.0 

%) and limited to two sites at Zeke’s 

Island (Table 5). The cause of the 

elevated TOC at these sites is unknown at 

this time. 

Figure 6. Percent area (± 95% Confidence Interval) 

of NC NERRS within specified ranges of total 

organic carbon (TOC, mg/g) in sediments.
22

3.2.2 Chemical Contaminants in Sediments 

In general, concentrations of most chemical contaminants were at low background levels 

(Appendix C). None of the NC NERRS sampling sites had detectable concentrations of 

pesticides (e.g.; DDT and its metabolites) or PBDEs (brominated flame retardants). Mean total 

PCB concentrations for each of the four reserves ranged from 0.120 ng/g dry weight (dw) at 

Rachel Carson to 0.599 ng/g dw at Zeke’s Island. PCB concentrations among the 30 individual 

stations ranged from < method detections limits (MDL) – 1.24 ng/g dw. Total PCB 

concentrations at all stations were well below the ERL for total PCBs of 22.7 ng/g dw (Long et 

al. 1995). Concentrations of PAHs (Appendix C) in sediments were also generally quite low 

throughout the four reserve locations. Only three of the 25 individual PAHs analyzed were 

present at detectable concentrations (naphthalene, perylene and benzo (b) fluoranthene) at any of 

the stations. No PAHs were detected at any of the Masonboro Sound stations and the highest 

concentration for any individual PAH was 80 ng/g dw (perylene) in a sample from Zeke’s Island. 

Perylene is a natural, plant-derived PAH that is produced through the process of diagenesis under 

anoxic or reduced conditions (Sanders et al. 2002). There are no ERL or ERM values for 

perylene or benzo (b) fluoranthene; however the maximum naphthalene concentration, 11.3 ng/g 

dw in a sample from Zeke’s Island, was well below the corresponding ERL value of 160 ng/g dw 

(Long et al. 1995). Mean total PAH concentrations for each of the four reserves ranged from 

9.71 ng/g dw at Currituck Banks to 68.6 ng/g dw at Zeke’s Island. The maximum total PAH 

concentration among the 30 stations, 154 ng/g dw, was well below the corresponding ERL value 

of 4022 ng/g dw (Long et al. 1995). 

Inorganic contaminant concentrations also were at low background concentrations for most 

analytes (Appendix C). Arsenic was the only inorganic analyte that was measured at elevated 

concentrations, above sediment quality guideline values, at any of the NERRS sampling stations 

(Table 6). Mean arsenic concentrations for each of the four reserves ranged from 1.87 μg/g dw 

at Currituck Banks to 7.99 μg/g dw at Zeke’s Island. Concentrations at individual sampling 

stations ranged from 0.69 – 15.1 μg/g dw. Arsenic concentrations exceeded the ERL (8.2 μg/g 

dw, Long et al. 1995) at two stations from Zeke’s Island and one station from Masonboro Sound. 

Hyland et al. (2000) also reported arsenic concentrations as high as 17.2 μg/g dw in estuarine 

sediments throughout NC. Arsenic concentrations are naturally elevated in soils along the 

southeastern coast (Shacklette and Boerngen 1984, Scott et al. 1994, Sanger et al. 1999, Van 

Dolah et al. 2004, 2006). Thus, it is likely that the moderately elevated levels of arsenic 

observed at a few of the NC NERRS stations (three of 30) were due to natural geological 

conditions rather than anthropogenic sources (also see Kimbrough et al. 2008, Riedel and 

Valette-Silver 2002). 

Mean ERM-Qs are listed by station in Appendix D. Stations with mean ERM-Qs > 0.058 were 

recorded as having poor sediment quality in a range associated with a high likelihood of 

impaired benthic condition (Hyland et al. 1999). Values ranging from > 0.02 to 0.058 were 

classified as moderately degraded and values ≤ 0.02 were considered to have “good” sediment 

quality previously associated with a high incidence of unimpaired benthic condition (Hyland et 

al. 1999). None of the NC NERRS stations had mean ERM-Q values above 0.058. Three 

stations (one from Masonboro Island and two from Zeke’s Island) had mean ERM-Qs between 

0.02 and 0.058 indicating slightly contaminated habitats with moderate risks of adverse 
23

conditions for benthic fauna. These three stations are the same ones with arsenic concentrations 

in excess of the lower-threshold ERL value and this single contaminant, probably derived from 

natural sources, was largely responsible for the moderately elevated mean ERM-Q values. 

Overall chemical contamination of a sediment sample was classified as high (i.e., poor sediment 

quality) if the mean ERM-Q was > 0.058, or if ≥ 1 contaminant exceeded its corresponding ERM 

value; moderate if the mean ERM-Q was > 0.02 to 0.058, or if ≥ 5 contaminants exceeded 

corresponding ERL values and none were above the ERM values; and low (i.e., good quality) if 

the mean ERM-Q was ≤ 0.02 and there were < 5 contaminants below ERL values and no 

contaminants above ERM values (Table 1). 

Based on these criteria, 89.5 ± 10.9% of the 

overall NC NERRS survey area had 

sediment contaminants in the low range and 

the remaining 10.5 ± 10.9% had 

contaminants in the moderate range (Table 5, 

Figure 7). None of the stations were 

classified as having high sediment 

contamination. For comparison, Hyland et 

al. (2000), using the above mean ERM-Q 

thresholds, reported low sediment 

contamination in 57% of NC estuaries statewide, moderate contamination in 27% of the 

area, and high contamination in 16% of the 

area. USEPA (2004), using the above 

numbers of ERL and ERM values that were 

exceeded as thresholds, reported low 

contamination in 99% and moderate 

contamination in the remaining 1% of 

southeastern estuaries region-wide. If the 

latter thresholds (based only on numbers of 

ERL/ERM values exceeded) were used in the 

present analysis, then 100% of the NC 

NERRS survey area would be classified as 

having low sediment contamination 

(Appendix D). 

Table 6. Number of stations by reserve and percent area within each reserve with contaminants 

in sediment that exceeded corresponding ERL and ERM Sediment Quality Guidelines (SQG) 

values (μg/g dry mass; Long et al. 1995). CB=Currituck Banks (n=4), RC=Rachel Carson (n=9), 

MI=Masonboro Island (n=12), and ZI=Zeke’s Island (n=5). 

 # stations > SQG 

Analyte SQG CB RC MS ZI 

% Area > SQG 

(± 95% C.I.) 

Arsenic ERL: 8.2 0 0 1 2 10.5 (10.9) 

Arsenic ERM: 70 0 0 0 0 0 

Figure 7. Percent area (± 95% Confidence 

Interval) of NC NERRS within specified ranges 

of chemical contamination in sediments.
24

3.2.3 Sediment Toxicity: Microtox 

Sediments from nine of the 30 stations, representing 31 ± 16.6% of the survey area, were 

classified as toxic based on the Microtox assay (Table 5, Appendix E). This measure of 

sublethal toxicity (reduction in microbial bioluminescence) was observed in sediments from two 

of seven stations at Rachel Carson, four of eight stations at Masonboro Island, and three of five 

stations at Zeke’s Island. None of the sediments from Currituck Banks caused toxicity. Three of 

the stations with significant toxicity (NC06MI08, NC06ZI02, and NC06ZI05) were the same 

ones described as having moderately degraded sediment quality, based on the mean ERM-Q, and 

which also had arsenic in excess of its corresponding ERL value. The remaining six stations that 

exhibited a significant Microtox response, were classified as having good sediment quality based 

on low levels of chemical contamination. This lack of concordance could be due to a number of 

factors including toxicity from unmeasured contaminants, or those without sediment quality 

guidelines, or oversensitivity of the Microtox assay relative to the influence of other 

physicochemical variables. Other authors (e.g., Van Dolah et al. 2006) have noted that this assay 

is very sensitive to sediment-associated contamination, but also has a tendency for false positives 

(i.e., toxicity without evidence of chemical contamination). Hyland et al. (2000 and references 

therein), in comparing results of Microtox tests conducted on sediments throughout NC estuaries 

to those documented from other coastal systems, reported toxicity in about 14% of the NC 

estuaries, 39% for the Hudson-Raritan estuary, 43% for Charleston Harbor, 45% for Boston 

Harbor, 57% for Savannah River, 68% Long Island Sound, 70% for Winyah Bay, and 96% for 

Biscayne Bay. Thus, aside from the potential oversensitivity of the Microtox assay, the 

estimated spatial extent of sediment toxicity throughout the present NC NERRS survey area, 

including all nine sites that tested positive in the Microtox assay, was within the lower end of the 

above range of spatial estimates for other coastal systems. 

3.3 Biological Condition 

3.3.1 Benthic Communities 

Macrobenthic infauna (> 0.5 mm) were sampled at a total of 30 stations throughout the four NC 

NERRS reserves. Three replicate grabs (0.04 m2

 each) were collected at all stations resulting in 

a total of 90 benthic grabs. A total of 310 taxa were identified from the 90 samples, including 

184 to the species level. Polychaetes were the dominant taxa, both by percent abundance (67%; 

Figure 8) and percent taxa (43%; Figure 8, Table 7). Crustaceans and bivalves were the second 

and third most dominant taxa respectively, both by % abundance (11% bivalves, 9% crustaceans) 

and % species (23% crustaceans, 16% bivalves). Collectively, these three groups represented 

86% of the total faunal abundance and 83% of the species throughout the four reserves. 

Crustaceans were represented mostly by amphipods (40 identifiable taxa, 13% of the total 

number of taxa) followed by hexapoda (13 larval insect taxa, 4.2% of total taxa) and decapoda 

(12 taxa, 3.9% of total taxa) (Table 7). 

Species richness, expressed as the number of taxa present in a 0.04-m2

 grab, ranged from 2 – 47 

taxa per grab with a mean of 20 taxa per grab (Table 8, Appendix F). Mean richness was highest 

at Rachel Carson (27 taxa per grab) and lowest at Zeke’s Island (9 taxa per grab) (Table 8, 

Figure 9). H′ diversity (log base 2 derived) ranged from 0.3 – 4.9 with a mean of 2.9. Mean H′
25

for each of the four individual reserves followed an identical pattern to species richness, with 

mean values being highest at Rachel Carson (4.5) and lowest at Zeke’s Island (1.8). A total of 

8,908 individual specimens were collected across the 30 stations (90, 0.04-m2

 grab samples). 

Densities ranged from 375 – 7,842 m-2 and averaged 2474 m-2. Mean density was highest at 

Rachel Carson NERR (2,725 m-2) and lowest at Zeke’s Island NERR (2,207 m-2). 

There was a great deal of variability in the composition of dominant taxa among the four reserve 

locations, possibly reflecting observed differences in salinity, percent silt-clay, and TOC content 

of sediment. The polychaete Streblospio benedicti was the most abundant species overall, 

though it displayed a wide range in density (means of 6.2 – 733/m2

) and frequency of occurrence 

(means of 16.6 – 93.3%) among the four reserves (Table 9). S. benedicti was particularly 

abundant at Masonboro Island and Zeke’s Island and relatively sparse at Currituck Banks. S. 

benedicti is a well known inhabitant of organically enriched sediments (Pearson and Rosenberg 

1978), which is consistent with its high abundance at Zeke’s Island where the highest 

percentages of TOC and fine-grained sediments were observed. Currituck Banks, which had the 

lowest salinity (oligohaline range) among the four reserves, stood out as having the highest 

densities of tubificid oligochaetes, larval insects of the genus Chironomus, and the polychaete 

Amphicteis floridus. The latter two dominant species at Currituck Banks in fact were not present 

in samples from the other three reserves. None of the species on the list of the 50 most abundant 

taxa (Table 9) are known non-indigenous species for the region of collection. 

The B-IBI is a multi-metric index providing a quantitative unbiased basis for coding a sample as 

degraded vs. non-degraded biologically. Typically, B-IBI values ≤ 1.5 are indicative of a highly 

degraded benthos, values ≥ 3 are indicative of a healthy benthos, and transitional values between 

1.5 and 3 reflect partial symptoms of stress (Van Dolah et al. 1999). The B-IBI for the four 

reserves ranged from 1 – 5 and averaged 3.6 (Table 8, Figure 9, Appendix F). Mean B-IBI was 

highest at Rachel Carson (4.5) and lowest at Masonboro Island and Zeke’s Island (3.2). Two of 

the five stations at Zeke’s Island and one of the 12 stations at Masonboro Island, together 

representing 10.5 ± 10.9% of the total survey area, had values ≤ 1.5 indicative of an impaired 

benthos (Table 5, Figure 10). Four other stations (one at Currituck Banks and three at 

Masonboro Island), together representing 13.4 ± 12.4% of the area, had values in the 

intermediate range. However, the majority (76.1 ± 15.5%) of the NC NERRS survey area had 

mean B-IBI values in the upper (≥ 3) range indicative of a healthy benthos (Table 5, Figure 10). 

Notably, all nine of the stations sampled at the Rachel Carson reserve had values in the upper 

range (Table 8, Appendix F). Hyland et al. (2000) reported a similar profile of benthic condition 

for estuaries state-wide, with B-IBI values ≥ 3 in 70% of the area, values from 1.5 – 3 in 15% of 

the area, and values ≤ 1.5 in 15% of the area. Similar estimates also have been reported for 

estuaries throughout the southeastern region, e.g., 79% with healthy benthic condition, 10% in 

the intermediate range, and 11% with degraded benthic condition (USEPA 2004). 
26

Figure 8. Relative compositions of major benthic taxonomic groups at NC NERRS. 

Data based on 3 replicate grabs (0.04m2) at each of 30 stations (Currituck Banks=4, 

Rachel Carson=9, Masonboro Island=12, Zeke’s Island=5). (A) % composition by 

abundance (total # individuals=8908), (B) % composition by taxa (total # taxa=310). 
27

Table 7. Summary of major taxonomic groups of benthic infauna and corresponding numbers of 

identifiable taxa in samples from NC NERRS. 

Taxonomic Group Number identifiable taxa % Total identifiable taxa 

Phylum Cnidaria 

Class Hydrozoa 1 0.3 

Class Anthozoa 1 0.3 

Phylum Platyhelminthes 1 0.3 

Phylum Nemertea 3 1.0 

Phylum Nemata 2 0.6 

Phylum Sipuncula 1 0.3 

Phylum Mollusca 

Class Gastropoda 25 8.1 

Class Bivalvia 50 16.1 

Class Polyplacophora 1 0.3 

Phylum Annelida 

Class Polychaeta 128 41.3 

Class Clitellata 7 2.3 

Phylum Arthropoda 

Subphylum Crustacea 

Class Malacostraca 

Order Decapoda 12 3.9 

Order Mysida 2 0.6 

Order Cumacea 2 0.6 

Order Tanaidacea 4 1.3 

Order Isopoda 5 1.6 

Order Amphipoda 40 12.9 

Class Branchiopoda 1 0.3 

Class Ostracoda 6 1.9 

 Subphylum Hexapoda 13 4.2 

Phylum Phoronida 1 0.3 

Phylum Brachiopoda 1 0.3 

Phylum Echinodermata 

Class Ophiuroidea 1 0.3 

Class Echinoidea 1 0.3 

Class Holothuroidea 1 0.3 

Phylum Chordata 1 0.3 

Total 310 100 
28

Figure 9. Box and wisker plots of benthic variables (mean abundance, mean H′, mean 

number of taxa, benthic index of biotic integrity [B-IBI]) among the four NC NERRS. 

Boxes=interquartile range, horizontal lines=median, whisker endpoints=10th and 90th 

percentile.

Figure 10. Percent area (± 95% Confidence Interval) of NC NERRS within specified ranges 

of benthic condition based on benthic index scores (B-IBI).
29

Table 8. Comparison of selected benthic characteristics among the NC NERRS. 

Mean # Taxa per grab Total # Taxa per station Mean Density (#/m2) Mean H ́ per gra

NERRS Site Mean Range Mean Range Mean Range Mean Range Overall 20 2 - 47 38 3 - 85 2474 375 - 7842 2.9 0.3 - 4.Currituck Banks 12 5 - 20 20 11 - 30 2508 583 - 5792 2.2 1.3 - 2.Rachel Carson 27 17 - 41 53 33 - 73 2725 750 - 4583 3.8 3.2 - 4.Masonboro Island 21 6 - 47 41 9 - 85 2387 417 - 7842 3.1 1.4 - 4.Zeke’s Island 9 2 - 18 15 3 - 30 2207 375 - 3808 1.8 0.3 - 2.
30

Table 9. Fifty most abundant benthic taxa at NC NERRS (listed in decreasing order of abundance among all sam

Mean density (m-2) and frequency of occurrence (% of samples from corresponding NERRS reserves) are listed f

NERRS and all four combined. CB=Currituck Banks (12 grabs), RC=Rachel Carson (27 grabs), MI=Masonboro 

and ZI=Zeke’s Island (15 grabs). Letters in parentheses refer to major taxonomic group: P = Polychaeta, O = OlBivalva, G = Gastropoda, C = Crustacea, In = Insecta, and N = Nemertea. 

Density (#/m2) Frequency (% 

Taxon Overall CB RC MI ZI Overall CB RStreblospio benedicti (P) 480.2 6.2 251.8 733 663.3 65.5 16.6 6Tubificidae (O) 191.6 952 72.2 79 68.3 55.5 91.6 3Mediomastus spp. (P) 185 151.8 163 445 58.8 6Nassarius obsoletus (G) 126.3 101 515 26.6 Tellina spp. (B) 97.7 195.3 97 1.6 52.2 8

Chironomus spp.(In) 56.1 420.8 8.8 66.6 Acteocina canaliculata (G) 55.8 179.6 4.8 25.5 6Maldanidae (P) 50.5 97.2 53 27.7 4Lumbrineris tenuis (P) 41.1 136.1 0.6 11.1 3

Amphicteis floridus (P) 37.2 279.1 5.5 41.6 Gemma gemma (B) 36.9 53.7 43 21.6 27.7 2Spiochaetopterus oculatus (P) 35.5 3.7 13 176.6 13.3 14Brania wellfleetensis (P) 33.6 5.5 80 13.3 14Haplocytheridea setipunctata (C) 33.6 103.7 4.8 3.3 22.2 4Laeonereis culveri (P) 33 162.5 25.9 0.6 20 15.5 58.3 1Rhepoxynius hudsoni (C) 33 41.6 51 11.1 1Nemertea (N) 27.7 37.9 20 50 54.4 7Prionospio spp. (P) 26.9 58.3 24 26.6 5Mediomastus ambiseta (P) 25.8 78.7 5.5 6.6 1Caulleriella sp. J (P) 25.5 75.9 6.9 12.2 1

Aricidea taylori (P) 23.3 76.8 0.6 8.8 2Parapionosyllis longicirrata (P) 22.7 2.7 55 13.3 3Hargeria rapax (C) 22.7 156.2 5.5 0.6 8.8 50 3

Capitella capitata (P) 22.5 2.7 33 50 14.4 1

Bivalvia (B) 22.5 4.1 26.8 34 1.6 34.4 16.6 5
31

Density (#/m2) Frequency (% 

Taxon Overall CB RC MI ZI Overall CB RAcanthohaustorius millsi (C) 21.6 70.3 1.3 3.3 7Cirratulidae (P) 18.8 17.5 25 21.6 30 2Tharyx acutus (P) 18.8 13.8 31 13.3 24.4 3Spionidae (P) 16.9 4.1 29.6 19 27.7 16.6 5

Axiothella mucosa (P) 15.8 37.9 11 18.8 44

Paraonis fulgens (P) 14.7 49 5.5 1Polydora cornuta (P) 14.7 6.2 1.8 33 1.6 12.2 16.6 3

Cirrophorus spp. (P) 14.4 15.7 24 20 14

Tellina iris (B) 13.3 35.1 6.9 15.5 3Parandalia tricuspis (P) 13 12 50 13.3 Aricidea suecica (P) 12.7 14.8 21 20 22

Scoloplos rubra (P) 11.3 25.9 3.4 13.3 20 4Leitoscoloplos spp. (P) 10.8 19.4 9.7 6.6 23.3 3

Listriella barnardi (C) 10.8 20.3 12 22.2 4

Nereididae (P) 10.2 3.7 21 5 15.5 14Nephtys picta (P) 9.7 7.4 19 22.2 22

Streptosyllis arenae (P) 9.7 11.1 16 10 14Ampelisca verrilli (C) 9.7 29.6 2 16.6 44

Armandia maculata (P) 9.1 6.4 18 10 14

Diplodonta spp. (B) 9.1 9.2 15 3.3 17.7 2

Tagelus divisus (B) 9.1 20.3 6.9 1.6 11.1 22

Tubulanus (N) 8.8 22.2 5.5 17.7 3Prionospio heterobranchia (P) 8.6 28.7 10 3Cyathura polita (C) 8.6 62.5 0.9 7.7 50 3

Corophiidae (C) 8 41.6 7.4 0.6 8.8 33.3 1

Table 9 continued. 
32

3.3.2 Chemical Contaminants in Fish Tissues 

Analysis of chemical contaminants in fish tissues (wet-weight concentrations of metals, PAHs, 

PBDEs, PCBs, and pesticides) was performed on homogenized filets (including skin) from 22 

samples of four species — white perch (Morone americanus), Atlantic croaker (Micropogonias 

undulatus), spot (Leiostomus xanthurus), and pigfish (Orthopristis chrysoptera). Many of the 

measured contaminants in these samples were below corresponding MDLs (Appendix G). 

However, twelve of the 22 inorganic elements that were measured (Al, As, Ba, Cr, Cu, Fe, Mn, 

Ni, Hg, Se, V, and Zn) were present at detectable levels consistently across all four fish species. 

Additionally, there were several organic contaminants that were present at detectable levels 

including total PCBs (all four fish species), 4,4'-DDD (croaker), 4,4'-DDE (white perch, croaker, 

and spot), dieldrin (croaker and spot), and mirex (croaker). 

USEPA (2000) developed human-health consumption limits for cancer and non-cancer (chronic 

systemic) health endpoints for a variety of contaminants (Table 3). The values listed in Table 3, 

against which measured concentrations were compared, represent risk-based limits associated 

with the consumption of four 8-ounce meals of fish per month for the general adult population 

(similar to the approach used by most state advisory programs, USEPA 2004). Cancer endpoints 

were based on a 1 in 100,000 risk level. Measured contaminant concentrations (Appendix G) 

fell well below both the cancer and non-cancer consumption limits for most chemicals. 

However, one white perch from Currituck Banks, of the 22 fish analyzed in this study, had 

mercury levels (0.14 ug/g wet) that exceeded the lower threshold for non-cancer effects (0.12 

ug/g wet). Also, inorganic arsenic (estimated as 2% of total arsenic (USEPA 2000)) exceeded 

both the lower and upper cancer thresholds in 16 of the 22 fish samples that were analyzed (all 

six pigfish and 10 of the 11 croaker) and the lower cancer threshold in one of two samples of 

spot (Table 10). In contrast, all three samples of white perch had levels of inorganic arsenic 

below the human-health consumption limits. None of the fish samples from the Currituck Banks 

reserve had inorganic arsenic above the consumption limits, though the remaining three reserves 

all contained fish with inorganic arsenic in the cancer-risk range. 

Greene and Crecelius (2006) assessed total and inorganic arsenic in samples of summer flounder, 

croaker, bass, and hard clams collected from Delaware estuaries. Roughly 18% of fish samples 

contained inorganic arsenic, though it was detectable in croaker in only one of five samples at a 

relatively low concentration (0.00057 μg/g wet). Croaker in the present study typically had 

higher levels of inorganic arsenic (ranging from 0.003 to 0.313 μg/g wet). This difference may 

be due to the relatively elevated levels of natural arsenic found in sediments along the NC coast 

(see above Section 3.2.2). We evaluated unpublished arsenic data from fish collected as part of 

the EPA EMAP Program (1995/97 data for 17 fish- nine croaker and eight spot, 

www.epa.gov/emap/nca/. Inorganic arsenic (estimated as 2% of total arsenic) exceeded both the 

upper and lower cancer thresholds in five of the 17 fish samples (two of nine croaker and three of 

eight spot) and the lower cancer threshold in three other samples (one croaker and two spot). 

While the proportion of these samples with arsenic levels above the cancer thresholds was lower 

than in the present study, this comparison does demonstrate that these levels are often exceeded 

in fish from other North Carolina locations. Additionally, other data for wild caught red drum 

from the southeastern and gulf coasts of the U.S. further demonstrate that US EPA cancer risk 
33

limits are regularly exceeded (11 of 13 samples), though the ranges (0.0044 – 0.057 μg/g wet) 

again appear to be lower than those observed in the present study (C. Browdy, personal 

communication, S.C. Department of Natural Resources, Charleston S.C.). Conversely, USEPA 

(2004) reported low levels of inorganic arsenic in fish tissues, below the cancer or non-cancer 

consumption limits, in all samples collected from estuaries throughout the southeastern U.S. 

Measured arsenic levels in the tissues of fish from these various studies may have been 

influenced by the size and age of the fish sampled. 

Table 10. Comparison of measured concentrations of inorganic arsenic in fish tissues (μg/g wet 

weight) to corresponding cancer and noncancer health endpoints, based on consumption of four 

8-ounce meals per months (US EPA 2000). CB=Currituck Banks, RC=Rachel Carson, 

MI=Masonboro Island, ZI=Zeke’s Island. 

Sample # Species NERR

S 

Concentrationa

(μg/g wet weight) 

> Noncancer 

Endpointsb

> Cancer 

Endpointsc

NC06CB01-a white perch CB 0.0024 

NC06CB01-b white perch CB 0.0031 

NC06CB03-b croaker CB 0.0032 

NC06CB04-a spot CB 0.0029 

NC06CB04-b white perch CB 0.0030 

NC06RC01-a pigfish RC 0.1185 ** 

NC06RC01-b croaker RC 0.3127 ** 

NC06RC01-c croaker RC 0.1292 ** 

NC06RC03-a pigfish RC 0.0724 ** 

NC06RC05-a pigfish RC 0.0386 ** 

NC06RC06-a pigfish RC 0.0781 ** 

NC06RC08-a pigfish RC 0.0536 ** 

NC06MI05-a croaker MI 0.1403 ** 

NC06MI09-a croaker MI 0.0879 ** 

NC06MI10-a croaker MI 0.0863 ** 

NC06MI12-a pigfish MI 0.1208 ** 

NC06ZI03-a croaker ZI 0.0993 ** 

NC06ZI03-b croaker ZI 0.0660 ** 

NC06ZI03-c croaker ZI 0.0558 ** 

NC06ZI03-d croaker ZI 0.0785 ** 

NC06ZI03-e croaker ZI 0.1298 ** 

NC06ZI05-a spot ZI 0.0137 * 

a. Inorganic arsenic concentration estimated as 2% of total arsenic. 

b. Tissue concentrations > 0.35 – 0.70 μg/g (wet weight) representing risks of human chronic systemic effects. 

*Measured concentration exceeds lower endpoint; **measured concentration exceeds upper endpoint. 

c. Tissue concentrations > 0.0078 – 0.016 μg/g (wet weight) representing human cancer risks at a 1 in 100,000 risk 

level. *Measured concentration exceeds lower endpoint; **measured concentration exceed upper endpoint.
34

3.3.3 Potential Linkages of Biological Condition to Ecosystem Stressors 

Multi-metric benthic indices are often used as indicators of pollution-induced degradation of the 

benthos (see review by Diaz et al. 2004) and have been developed for a variety of estuarine 

applications (Engle et al. 1994, Weisberg et al. 1997, Van Dolah et al. 1999, Llannso 2002, 

Llannso et al. 2003). A desired feature of these indices is the ability to differentiate impaired vs. 

unimpaired benthic condition, based on a number of key biological attributes (e.g., numbers of 

species, abundance, dominance, percent sensitive taxa), while attempting to take into account 

variations associated with natural controlling factors. In the present study, we utilized the 

benthic index of biotic integrity (B-IBI) for southeastern estuaries, developed by Van Dolah et al. 

(1999), to provide a quantitative unbiased basis for coding each sample as degraded vs. nondegraded biologically. An additional approach used here was to evaluate benthic condition 

(expressed as B-IBI scores) in relation to sediment contamination and toxicity, the combination 

of which is often referred to as the Sediment Quality Triad (SQT). The SQT has been shown to 

be very effective as a “weight-of-evidence” approach to assessing pollution-induced degradation 

of the benthos (Long and Chapman 1985, Chapman 1990). 

Overall, about 66% of the survey area (20 stations) had a healthy benthos with low levels of 

sediment contamination and no toxicity (Table 11). No part of the NC NERRS had a degraded 

benthos with both high contamination and toxicity (i.e., positive hits in all three legs of the SQT). 

Twenty-one percent of the survey area (six stations) had a degraded benthos co-occurring with 

significant sediment toxicity, but without elevated levels of measured chemical contaminants, 

possibly suggesting toxicity/bioeffects from other unmeasured stressors. The remaining 13% of 

the survey area, represented by four stations, showed some symptoms of stress, but no 

connection between adverse biological and exposure conditions. These cases included one 

station with a degraded benthos accompanied by low levels of contaminants and no toxicity, and 

three stations that had significant Microtox toxicity but no evidence of degraded benthic 

condition or sediment contamination. Possible explanations include: contaminants were present 

but were not bioavailable; contaminants were present in toxic bioavaliable forms, but there was 

no adverse benthic effects due to biological avoidance or resistance mechanisms; or benthic 

impacts were caused by other natural stressors (e.g., biological interactions, physical 

disturbances of sediment). It is noteworthy that none of the stations in the Rachel Carson reserve 

had a degraded benthos. 

A closer look at the co-occurrences of degraded benthic condition and various stressor indicators 

further highlights the relatively close agreement between low B-IBI scores (<3) and significant 

Microtox toxicity, as well as the possible influence of stressors other than the measured chemical 

contaminants as sources of the observed bioeffects (Table 12). Six of the seven stations with 

degraded benthic condition also had significant Microtox toxicity. Two of these stations, both in 

the Zeke’s Island reserve, also contained high levels of TOC, in a reported range (> 35 mg/g) 

associated with a high risk of disturbance from organic over-enrichment (Hyland et al. 2005). 

Interestingly, none of the stations with a degraded benthos and significant toxicity co-occurred 

with high levels of measured sediment contamination. As noted above, this may be due to 

toxicity from other unmeasured sediment contaminants. None of the stations with a degraded 

benthos also had low DO in a range (< 2.0 mg/L) potentially harmful to benthic fauna. 
35

There was little concordance between the observed incidence of fish-tissue and sediment 

contamination (Table 13). Inorganic arsenic in excess of cancer-risk consumption limits was the 

only contaminant that exceeded human-health guidelines for cancer or non-cancer systemic 

effects. All but one station where such an exceedance occurred had sediments with very low 

mean ERM-Qs and no contaminants in excess of corresponding ERL or ERM values. Generally, 

with the exception of arsenic (or estimated inorganic arsenic), most chemical contaminants were 

below detection limits or present at low background levels in both sediments and fish tissues. 
36

Table 11. Summary of sediment quality based on combined measures of sediment contamination, sediment toxi

benthic communities. 

Type Effect 

Sediment 

Cont.a

Toxicityb Degraded 

Benthosc

No. 

Stations 

% Area 

(± 95% C.I.) Possible Conclusion 

+ + + 0 0 Degraded benthos with high contamination and t

evidence of contaminant induced degradation of 

+ - + 0 0 

- + + 6 21.1 (14.4) 

Degraded benthos with high contamination or toxunder-sensitivity of assays or field and lab bioeff

unmeasured stressors. 

- - + 1 2.9 (5.7) 

+ + - 0 0 + - - 0 0 

- + - 3 9.9 (10.8) 

Some stress, but no connection between adverse 

exposure conditions: contaminants not bioavailabpresent in toxic bioavailable forms, but no clear bto avoidance or resistance; or benthic impacts caustressors (e.g., biological interactions, physical dsediment). 

- - - 20 66.1 (17.6) Healthy benthos with low levels of sediment con

toxicity. 

a. Mean ERM-m > 0.058 or ≥ 1 ERM value exceeded. 

b. Significant Microtox toxicity. 

c. B-IBI < 3. 
37

Table 12. Evaluation of benthic condition in relation to various possible stressors. 

A. 

Stressor Indicatora NERRS 

Site 

Stations with 

Degraded Benthos 

(B-IBI < 3) 

B-IBI 

Score mERM-Q # Contaminants > ERM # Contaminants > ERL DO (mg/L) TOC 

Currituck Banks CB01 2 0.003612 0 0 8.3 

MI03 2.5 0.008107 0 0 5.34 

MI04 2 0.008873 0 0 5.08 MI08 1.5 0.020689 0 1 5.06 

Masonboro Island 

MI09 2.5 0.015499 0 0 6.19 

Zeke’s ZI02 1.5 0.036887 0 1 5.9 3Island ZI05 1 0.035535 0 1 5.44 3

a. Bold values exceed corresponding probable effect threshold levels. B. 

Type Effect No. of Stations % Area (± 95% C.I.) 

Healthy benthos with low stressor levels 20 66.1 (17.6) Healthy benthos with ≥ 1 stressor at high risk level 3 9.9 (10.8) Degraded benthos with low stressor levels 1 2.9 (5.7) Degraded benthos with ≥ 1 stressor at high risk level 6 21.1 (14.4) 
38

Table 13. Comparison of fish tissues contaminant levels to corresponding sediment contaminants at station with 

values above human health endpoints. 

Station Fish Type Contaminants Sediment Mean ERM-Q # of contaminants in sediment > ERL # of contamin

in sediment > 

NC06CB04 White Perch Mercury 0.009096 0 0 

NC06MI05 Atlantic Croaker Arsenic 0.003244 0 0 NC06MI09 Atlantic Croaker Arsenic 0.015499 0 0 NC06MI10 Atlantic Croaker Arsenic 0.00422 0 0 NC06MI12 Pigfish Arsenic 0.003187 0 0 

NC06RC01 Pigfish, Atlantic Croaker Arsenic 0.00458 0 0 

NC06RC03 Pigfish Arsenic 0.004996 0 0 NC06RC05 Pigfish Arsenic 0.014272 0 0 NC06RC06 Pigfish Arsenic 0.004908 0 0 NC06RC08 Pigfish Arsenic 0.011519 0 0 

NC06ZI03 Atlantic Croaker Arsenic 0.009127 0 0 

NC06ZI05 Spot Arsenic 0.035535 1 0 
39

3.4 Overall Ecological Condition and Human Factors 

As noted above, the majority (about 66%) of the NC NERRS had a healthy benthos without 

signs of significant sediment contamination or toxicity (Figure 11, Table 11). Moreover, no part 

of the survey area was found to have degraded benthic condition accompanied by both high 

sediment contamination and toxicity (positive hits in all three legs of the SQT). Ecological 

condition within the NC NERRS, based on such a SQT approach, appears to be slightly healthier 

compared to an earlier assessment of conditions conducted throughout North Carolina estuaries 

state-wide (Hyland et al. 2000). The latter authors, who used similar methods and indicators, 

reported 54% of estuarine habitat being in good condition and 7% having degraded benthic 

condition with high sediment contamination and toxicity. Another 12% of the area showed 

evidence of a degraded benthos coupled to significant pollutant exposure (high sediment 

contamination or toxicity though not both). The adverse environmental conditions in the earlier 

state-wide assessment tended to be concentrated spatially in the Neuse and Pamlico Rivers and 

their tributaries. Hyland et al. (2000, Figs. 6 and 7 therein) also pointed out that, while 

detectable in some locations, the spatial extent of sediment contamination and toxicity observed 

for these North Carolina estuaries is much less in comparison to other U.S. coastal regions where 

similar studies have been performed. 

Figure 11. Summary of sediment quality based on combined measures of benthic condition 

(degraded = B-IBI < 3), sediment toxicity (significant Microtox toxicity), and sediment 

contamination (mean ERM-Q > 0.058 or ≥ 1 ERM value exceeded). 
40

Water quality measurements across the NC NERRS exhibited some signs of elevated nutrient 

levels, including DIN (25% of area classified as fair), DIP (7% of area classified as poor and 

28% as fair), and chlorophyll a (11 % of area classified as poor and 34% as fair). DO levels, 

however, were in the high range (> 5 mg/L) across most of the survey area (96%). These results 

are very similar to those published in the National Coastal Condition Report (USEPA 2004) for 

estuaries throughout the southeastern U.S., with the exception of DO. In this latter case, the 

percent area with high DO (“good” category) was observed over a much smaller portion of area 

region-wide (74%) in comparison to the present NC NERRS. Although there were symptoms of 

eutrophic conditions in the NC NERRS, as evidenced by the poor to fair levels of chlorophyll a 

levels across a large area (45%), the majority of NC NERRS had all water quality measurements 

in the good to fair condition. Our evaluation of water quality of the NC NERRS is in general 

agreement with results from the National Estuarine Eutrophication Assessment Program for the 

southeast region, which used very different assessment techniques, but found 2 of the 3 studied 

North Carolina estuarine systems having low to moderate symptoms of eutrophication based on 

chlorophyll and DO (Bricker et al. 2007). 

There has been an evolving interest recently in the U.S. and other parts of the world to adopt an 

ecosystem approach to the management (EAM) of coastal resources (Murawski 2007, Marine 

Ecosystems and Management 2007). Integrated ecosystem assessments (IEAs) have been 

identified as an important component of an EAM strategy (Levin et al. 2008, Murawski and 

Menashes 2007). An IEA is a synthesis and quantitative analysis of information on relevant 

natural and socio-economic factors in relation to specified ecosystem management goals. Key 

steps in the IEA process include the assessment of baseline conditions defining the status of the 

system as well as the assessment of stressor impacts and their links to source drivers and 

pressures. Another underlying tenet in this process is the role of humans as both a source and 

receptor of ecosystem effects. While the focus of the present study has been on indicators of 

ecological condition and its potential linkage to humans as sources of stress, some of the 

indicators that we have included can be used to help evaluate how key human uses of these 

resources are being affected as a result of the current status of ecosystem condition. These 

include indicators of potential human-health risks (fish contaminant levels) and aesthetic value 

(e.g., water clarity, marine debris, noxious odors). 

As an indicator of potential human-health risks, concentrations of chemical contaminants 

(metals, PAHs, PBDEs, PCBs, pesticides) were measured in whole fillets of 22 fish samples 

from 14 stations and compared to EPA consumption limits for cancer and non-cancer (chronic 

systemic health) risks. While most contaminants were below MDLs or the consumption limits, 

one fish of the 22 (4%) contained levels of mercury that exceeded the lower threshold for noncancer effects, but there was no clear pattern evident of widespread consumption concerns due to 

Hg. More importantly, 17 of the fish samples (77%) from 11 of the 14 stations where fish were 

caught (79%) contained inorganic arsenic above the limits for cancer risks. In comparison, 

USEPA (2004) reported contaminants in whole fish tissues at concentrations above these same 

risk-based guidelines at a much lower percentage of stations (20%) for southeastern estuaries 

region-wide. Moreover, inorganic arsenic was not one of the contaminants that exceeded the 

guidelines; contaminants found at such elevated levels in this latter case were total PAHs and 

PCBs. Related data, focused on the Albemarle-Pamlico Estuarine System portion of the region 
41

(USEPA 2006), indicate a higher percentage (30%) of stations where the human-health 

guidelines were exceeded. The elevated levels of arsenic that were observed consistently among 

the majority of fish tissues in the present study most likely originate from the naturally elevated 

concentrations of arsenic in crustal rocks of the area and therefore probably are not indicative of 

human impacts. None of the fish with elevated inorganic arsenic levels showed obvious 

pathological disorders (e.g., tumors, lesions, fin rot). 

Aesthetic indicators included measures of water clarity (TSS), presence of debris (“trash”) in 

surface and bottom waters, visual evidence of oil sheens in surface waters or bottom sediments, 

and noxious odors. As noted previously, TSS concentrations in surface waters ranged from 6.0 

to 24.0 mg/L and averaged 12.0 mg/L, which appear to be within a normal range for such 

naturally turbid waters characteristic of southeastern estuaries. There was no evidence of marine 

debris, either floating or collected in bottom grabs, at any of the reserve sites. Similarly, we 

observed no signs of surface oil slicks or oil sheens in bottom sediments. The only positive 

evidence of an aesthetic effect was the occurrence of noxious odors in bottom sediments at a 

number of the stations. A total of 16 stations, representing 53.0% of the overall survey area, had 

sediments with noxious (hydrogen sulfide) odors. By reserve, this condition was observed at 

four of the five stations at Currituck Banks, two of the nine stations at Rachel Carson, six of the 

12 stations at Masonboro Island, and four of the five stations at Zeke’s Island. The most 

probable source of the sulfide smell is the natural decomposition of detrital organic matter across 

these near-coastal estuarine sites. 

With some exceptions, as discussed above, the status of subtidal estuarine habitats throughout 

the NC NERRS appears to be in relatively good to fair ecological condition overall, with the 

majority of the area (about 54%) having various water quality, sediment quality, and biological 

(benthic) condition indicators rated in the healthy to moderate/intermediate range (Table 14). 

This is consistent with an overall rating of good to fair condition for southeastern estuaries 

region-wide (USEPA 2004). Only three stations in the present study, representing 10.5% of the 

area, had one or more indicators of water quality, sediment quality, and biological condition 

rated as poor/degraded in all three categories. While such a conclusion is encouraging from a 

coastal management perspective, it should be viewed with some caution. For example, although 

co-occurrences of adverse biological and abiotic environmental conditions were limited spatially, 

at least one indicator of adverse condition (rated in the poor/degraded range) was observed over 

a broader area (35.5%) represented by 11 of the 30 stations sampled. In addition, the fish-tissue 

contaminant data were not included in these overall spatial estimates (see Table 14); however, as 

noted above, there is evidence that fish in the area have elevated levels of inorganic arsenic, 

above consumption limits for human cancer risks, though most likely derived from natural 

sources. Similarly, aesthetic indicators are not reflected in these spatial estimates of ecological 

condition, though as noted above there was evidence of noxious odors at many of the stations. 

Such symptoms reflect a growing realization that North Carolina estuaries are under multiple 

pressures from a variety of natural influences as well as anthropogenic factors, including rapidly 

increasing human populations and coastal development, nutrient enrichment and sedimentation 

from agriculture, and industrialized point sources of pollution (Mallin et al. 2000). These data 

also suggest that, while current status of overall ecological condition appears to be good to fair, 

long-term monitoring is warranted to track any potential changes in the future. This study 
42

establishes an important baseline of overall ecological condition within the NC NERRS that can 

be used to evaluate such changes and to trigger appropriate management actions in this rapidly 

evolving coastal environment. 

Table 14. Estimates of overall ecological condition at NC NERRS based on combined 

indicators of water quality, sediment quality, and biological condition (note: fish tissue 

contaminant data are not included in these calculation of % area, since they represent only a 

portion of the total stations). 

Condition No. of 

Stations 

% Area 

(± 95% C.I.) a

All water quality, sediment quality, and biological condition 

indicators rated as “good/healthy” 

8 27.1 (15.4) 

b

One or more water quality, sediment quality, or biological 

condition indicators rated “Moderate/Fair” (but none as 

‘Poor/Degraded”) 

8 26.9 (16.4) 

c

One or more water quality, sediment quality, or biological condition 

indicators rated as “Poor/Degraded” 

11 35.5 (16.0) 

d

One or more water quality, sediment quality, and biological 

condition indicators rated as “Poor/Degraded” 

3 10.5 (10.9) 

a. DO > 5 mg/L, DIN < 0.1 mg/L, DIP < 0.01 mg/L, CHLa < 5 mg/L, TOC < 20 mg/g, mean ERM-q ≤ 0.02 or < 5 

ERL values exceeded and no ERM value exceeded, no Microtox toxicity, and B-IBI ≥ 3. 

b. DO 2-5 mg/L, DIN 0.1-0.5 mg/L, DIP 0.01-0.05 mg/L, CHLa -5-20 mg/L, TOC 20-50 mg/g, mean ERM-q 0.02-

0.058 or ≥ 5 ERL values exceeded and no ERM value exceeded, no Microtox toxicity, and B-IBI 1.5-3. 

c. DO < 2 mg/L, DIN > 0.5 mg/L, DIP > 0.05 mg/L, CHLa > 20 mg/L, TOC > 50 mg/g, mean ERM-q ≥ 0.058 or ≥

1 ERM value exceeded, significant Microtox toxicity, and B-IBI ≤ 1.5. 

d. See “c” thresholds. 
43

4.0 Overall Project Summary and Conclusions 

The present report is part of a two-volume set summarizing results of a collaborative NCCOSNERRS effort to assess the status of ecosystem conditions and potential stressor impacts at 

NERRS sites in the southeastern U.S., and to provide this information as a basis for monitoring 

future conditions in these same areas or in other NERRS locations. There are two 

complementary components of this overall initial effort: (1) a sentinel habitats study designed to 

evaluate the impacts of development on tidal creek ecosystems, including potential impacts to 

human health and well-being; and (2) a probabilistic monitoring component to assess the spatial 

extent of ecological condition throughout sub-tidal estuarine waters, based on the status of 

various measured ecological indicators relative to specific management thresholds. The tidal 

creek component, discussed in Volume I (Sanger et al. 2008), focused on NERRS sites at Sapelo 

Island, Georgia and Masonboro Island, North Carolina and was coordinated with results of 

related tidal creek work in South Carolina. The sub-tidal probabilistic component, discussed in 

the present Volume II, was conducted throughout all four North Carolina NERR locations 

(Currituck Sound, Rachel Carson, Masonboro Island, and Zeke’s Island). Together, the two 

project components are intended to provide a demonstration of the utility of the complementary 

assessment tools, one serving as a sentinel of environmental signals in areas of estuaries where 

signals are likely to occur (i.e., tidal creeks close to pollutant sources), and the other providing a 

quantitative basis for assessing the relative proportions of degraded vs. non-degraded conditions 

throughout a targeted resource category (i.e., sub-tidal estuarine waters of a reserve) relative to 

the various measured indicators and associated management thresholds. While providing new 

information on the status of ecological condition and human health risks in several southeastern 

U.S. NERRS locations, the results also are intended to serve as a useful framework of assessment 

strategies that could be applied systematically across other reserves to support broader regional 

and national comparisons. 

4.1 Summary Points from Volume I: Assessing Impacts of Coastal Development on the 

Ecology and Human Well-Being of Tidal Creek Ecosystems (from Sanger et al. 2008). 

Southeastern tidal creeks and associated watersheds are sensitive to coastal development and 

provide an early warning of potential degradation from upland land uses well before adverse 

conditions would be detected in larger coastal waters (e.g., tidal rivers, bays). Accounting for the 

spatial variability in hydrological and other watershed attributes among individual tidal creek 

systems is an important factor to consider in assessing the environmental quality of these 

habitats. Thus, the application of an appropriate tidal creek classification scheme in the sampling 

design process to accommodate such variability was a critical aspect of the research described in 

Volume I. One important finding of this research was that the sensitivity of tidal creeks to 

changes in the environmental quality of the surrounding watersheds diminishes downstream 

toward the mouths of the creeks. Smaller intertidal creeks generally had higher concentrations of 

non-point source pollutants (e.g., water quality, nutrients, and pathogen indicators), which likely 

reflect both the greater upland runoff component and estuarine dilution influence (i.e., tidal 

flushing) associated with larger creeks. Additionally, indicators of deteriorating environmental 

quality were found to vary directly with increasing levels of impervious cover, the latter allowing 

greater inputs of runoff and associated pollutants from the surrounding watershed into tidal 
44

creeks, particularly in headwater regions. The integrity and productivity of headwater portions 

of tidal creek environments are often impaired by land use changes and associated non-point 

source pollution, suggesting that these habitats serve as valuable early-warning sentinels of 

ensuing stress including ecological and potential public health threats (e.g., seafood consumption 

advisories, swimming advisories). A conceptual model of these linkages was validated and 

expanded for the southeastern US. Lastly, the tidal creek study and its associated conceptual 

model provide a useful framework for forecasting potential changes in ecological and human 

health indicators within these systems in relation to varying watershed attributes and land use 

patterns. 

4.2 Summary Points from Volume II: Assessing Ecological Condition and Stressor Impacts 

in Subtidal Waters of the North Carolina NERRS (Present Volume) 

This component of the project was aimed at assessing the status of ecological condition and 

stressor impacts in subtidal estuarine waters throughout the four North Carolina NERR locations 

(Currituck Sound, Rachel Carson, Masonboro Island, and Zeke’s Island). Sampling incorporated 

multiple indicators of ecosystem condition including measures of water quality, sediment 

quality, biological condition, and potential threats to human health and well-being (e.g., fishtissue contaminant levels relative to human health consumption limits, various aesthetic 

properties). A probabilistic sampling design permitted statistical estimation of the spatial extent 

of degraded versus non-degraded condition across these estuaries relative to specified threshold 

levels of the various indicators (where possible). With some exceptions, the status of this reserve 

appeared to be in relatively good to fair condition overall, with the majority of the area (about 

54%) having various water quality, sediment quality, and biological (benthic) condition 

indicators rated in the healthy to intermediate range of corresponding guideline thresholds. Only 

three of the 30 stations sampled, representing 10.5% of the area, had one or more of these 

indicators rated as poor/degraded in all three categories. However, although co-occurrences of 

adverse biological and abiotic environmental conditions were limited spatially, at least one 

indicator of ecological condition rated in the poor/degraded range was observed over a broader 

area (35.5% represented by 11 stations). In addition, fish-tissue contaminant data were not 

included in these overall spatial estimates; however, the majority of samples (77% of fish that 

were analyzed, from 79%, of stations where fish were caught) contained inorganic arsenic above 

the consumption limits for human cancer risks, though most likely derived from natural sources. 

Such symptoms reflect a growing realization that North Carolina estuaries are under multiple 

pressures from a variety of natural and human influences. These data also suggest that, while the 

current status of overall ecological condition appears to be good to fair, long-term monitoring is 

warranted to track potential changes in the future. This study establishes an important baseline 

of overall ecological condition within the NC NERR that can be used to evaluate any such future 

changes and to trigger appropriate management actions in this rapidly evolving coastal 

environment. 

4.3 Concluding Remarks on Coastal Management Applications and Opportunities 

NCCOS’s mission, as defined in its FY05-09 Strategic Plan (NCCOS 2004), is to provide coastal 

managers with scientific information and tools needed to balance society’s environmental, social, 

and economic goals. The NCCOS Strategic Plan also calls for baseline assessments of 
45

ecological resources and potential stressor impacts in NERRS and other NOAA protected areas. 

The NERRS’ mission is to practice and promote coastal and estuarine stewardship through 

innovative research and education activities focused on the NERRS (NERRS 2005). The present 

collaborative studies sought to address common research and management goals supportive of 

both program missions. The two studies provide new information on the current status of the 

ecological condition and human health risks at NERRS sites and neighboring waters in Georgia, 

South Carolina, and North Carolina as well as a set of complementary assessment tools for 

monitoring future conditions in these same areas or in other NERRS locations. The tidal creek 

study and its associated conceptual model (Volume I) provide a framework for forecasting 

potential changes from coastal development on the ecological and human health and well-being 

within these systems. The tidal creek study also exemplifies the utility of these habitats as a 

sentinel of environmental signals in areas of estuaries (e.g., in upper reaches close to pollutant 

sources) where signals are most likely to occur. The probabilistic sampling approach used in the 

subtidal assessment (Volume II) provides an additional unbiased statistical basis for quantifying 

the spatial extent of condition relative to the various measured indicators and desired 

management thresholds, throughout a targeted resource category, and thus a quantitative baseline 

for monitoring how the relative proportions of healthy vs. degraded areas may be changing with 

time. Thus, in addition to providing new information on the status of ecosystem conditions in 

specific southeastern U.S. NERRS locations, the results also are intended to serve as a 

framework of assessment strategies that could be applied systematically across other reserves to 

support national comparisons. Such ecological assessment tools would also complement systemwide, water-quality monitoring program (SWMP) and other site-specific research activities 

currently underway in the NERRS program. 

Such baseline assessments of the status of ecosystem conditions and stressor impacts also 

provide the first steps in the implementation of Integrated Ecosystem Assessments (IEAs) of 

NERRS sites. An IEA is a synthesis and quantitative analysis of information on relevant natural 

and socio-economic factors in relation to specified ecosystem management goals (Murawski and 

Menashes 2007, Levin et al. 2008). The NERRS, as a system of protected areas, offers an ideal 

series of place-based sites for an IEA, which includes the assessment of baseline conditions 

defining current ecosystem status as well as potential stressor impacts and their links to source 

drivers and pressures (as was the focus here). NOAA has placed an emphasis on conducting 

IEAs to support improved ecosystem approaches to management (EAM) within its protected 

coastal resources in order to offer coastal managers a more comprehensive framework to their 

coastal decision making. Such an approach requires increased understanding of these complex 

systems and improved integration and collaboration in their management. 

Related to the above point, as a NOAA protected resource, the NERRS offers an ideal 

opportunity to become a suite of place-based reference sites across the nation for documenting 

status and trends in coastal ecosystem conditions among reserves and in comparison to other 

non-protected areas. Results of the present two studies have provided new information on the 

status of conditions at NERRS sites in the southeastern U.S. These areas were found to be 

reasonable regional references, with the caveat that some symptoms of stress were detectable and 

thus the realization that such areas and surrounding watersheds are under multiple pressures from 

a variety of natural and human influences. Long-term monitoring is warranted to track potential 

changes in the future. The data and assessment strategies provided here can be applied in any 
46

such efforts for these same areas, as well as in any future surveys in other NERRS sites to 

support broader-scale regional and national comparisons. 

Another underlying project goal is to make the present information and assessment tools readily 

available for meeting NERRS research and management needs. There is a tremendous 

opportunity to achieve this goal through the educational and outreach resources of NERRS, 

including their strong education programs, Coastal Training Programs (CTP), and stewardship 

coordinators. Any related efforts to inform the public and coastal management community 

through targeted presentations and products derived from these studies should help to expand 

their utility toward addressing important coastal management and human health concerns. 

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52
53

Appendix A. Locations, depths, and water and sediment characteristics of 30 stations sampled in NC NERRS in 

Near-Bottom Water NERRS 

Site Station Latitude (DD) Longitude (DD) Depth (m) Temp. (oC) Salinity (ppt) DO (mg/L) pH TSSab (mg/L) TOC (mg/g) % 

(sand

Currituck Bank 1 36.38929 -75.8413 1 24.25 2.7 8.3 8.01 20 (30) 1.98 9 2 36.39447 -75.8468 1 23.69 2.74 6.81 7.64 18.5 (27.75) 25.11 

 3 36.39127 -75.8590 1 25.21 2.59 8.97 8.7 18.5 (27.75) 2.68 7

 4 36.39926 -75.8474 1 23.19 2.71 5.92 7.28 13.5 (20.25) 8.63 7

Masonboro Island 1 34.12385 -77.8679 2.02 24.39 35.23 5.8 7.82 6 (9) 1.9 8 2 34.18657 -77.8185 3.83 25.03 36.14 6.29 8.02 8.5 (12.75) 0.53 9

 3 34.12228 -77.8588 1.05 23.61 21.91 5.34 7.59 8 (12) 4.71 8

 4 34.11205 -77.8627 0.66 23.3 19.95 5.08 7.69 8.5 (12.75) 5.29 8

 5 34.15813 -77.8507 1.2 22.87 33.86 5.34 7.74 9.5 (14.25) 0.91 9

 6 34.17625 -77.8258 3.4 25.06 36.2 5.84 8.03 9.5 (14.25) 0.81 9

 7 34.16906 -77.8425 1.24 23.23 35.53 5.67 7.86 6 (9) 1.32 9

 8 34.13656 -77.8503 1.15 23.65 29.62 5.06 7.63 15.5 (23.25) 16.7 

 9 34.09257 -77.8709 1.3 24.89 35.79 6.19 7.83 8.5 (12.75) 10.27 7

 10 34.14796 -77.8526 0.85 22.48 29.49 4.61 7.65 9.5 (14.25) 1.8 9

 11 34.13828 -77.8643 2.26 25.26 36.22 5.72 7.94 6 (9) 2.54 9

 12 34.17035 -77.8296 2.15 24.76 36.09 6.07 8.03 7 (10.5) 1.11 9

Rachel Carson 1 34.70448 -76.6583 4.3 25.3 36.05 5.77 8.02 10 (15) 0.86 9 2 34.70024 -76.6453 0.8 25.07 35.69 5.81 7.94 19 (28.5) 1.07 9 3 34.69266 -76.6123 1.03 23.31 34.71 5.56 7.75 14 (21) 2.26 9 4 34.70261 -76.6372 1.37 23.94 33.89 5.78 7.57 24 (36) 0.82 9 5 34.69811 -76.6022 0.95 23.91 34.76 6.01 7.78 14.5 (21.75) 8.99 5

 6 34.71168 -76.6732 1.1 23.74 32.78 5.23 7.43 11.5 (17.25) 2.21 8

 7 34.70574 -76.6747 2.27 25.39 35.9 5.89 8.04 7.5 (11.25) 0.48 9

 8 34.69778 -76.6093 1.05 25.26 35.96 5.88 7.92 7.5 (11.25) 6.24 6 9 34.70010 -76.6307 1.51 25.6 35.65 6.32 7.9 10 (15) 0.7 Zeke's Island 1 33.92343 -77.9484 1.07 24.14 11.42 5.66 7.61 14.5 (21.75) 4.06 8 2 33.95100 -77.9457 0.69 23.67 12.13 5.9 7.7 18 (27) 37.75 2 3 33.93167 -77.9541 1.97 23.8 9.89 5.7 7.56 13.5 (20.25) 2.69 9 4 33.93312 -77.9391 1.01 24.72 11.83 5.68 7.76 11 (16.5) 8.13  5 33.95433 -77.9360 1.41 24.84 11.73 5.44 7.53 11.5 (17.25) 36.79 3

a. Surface water. 

b. Value in parentheses is TSS converted to NTU (reference). 
54

Appendix B. Summary by station of nutrient and chlorophyll concentrations in surface waters at 30 stations sam

in September 2006. 

NERRS Site Station 

DIN 

(mg/L) 

NH4+

(mg/L) 

TDN 

(mg/L) 

TN 

(mg/L) 

DIP 

(mg/L) 

TDP 

(mg/L) 

TP 

(mg/L) 

Si 

(mg/L) 

CHL a

(μg/L) 

Phaeophyt

(μg/L) 

Currituck Banks 1 0.023 0.020 0.54 1.53 0.0029 0.0072 0.0474 1.50 31.75 3. 2 0.010 0.007 0.47 1.40 0.0020 0.0049 0.0363 1.31 32.6 5. 3 0.014 0.011 0.46 1.30 0.0024 0.0043 0.0350 1.36 29.45 4. 4 0.023 0.020 0.53 1.36 0.0024 0.0056 0.0397 1.29 33.07 5.Masonboro Island 1 0.007 0.003 0.20 0.31 0.0086 0.0191 0.0418 0.25 5.25 1. 2 0.008 0.003 0.18 0.29 0.0046 0.0151 0.0358 0.11 3.66 1. 3 0.104 0.055 0.51 0.59 0.0271 0.0443 0.0627 0.84 3.43 1. 4 0.115 0.056 0.56 0.64 0.0338 0.0501 0.0680 0.98 2.70 1. 5 0.014 0.006 0.28 0.39 0.0131 0.0225 0.0433 0.32 5.24 4. 6 0.008 0.003 0.18 0.27 0.0051 0.0152 0.0340 0.12 3.89 1. 7 0.008 0.003 0.27 0.37 0.0062 0.0190 0.0376 0.23 3.70 1. 8 0.054 0.035 0.34 0.48 0.0133 0.0270 0.0626 0.50 6.15 2. 9 0.018 0.008 0.22 0.31 0.0075 0.0203 0.0432 0.22 3.59 1.2 10 0.068 0.042 0.38 0.49 0.0163 0.0347 0.0585 0.57 4.97 2. 11 0.008 0.003 0.19 0.28 0.0068 0.0138 0.0326 0.16 4.16 1.4 12 0.007 0.003 0.18 0.28 0.0079 0.0161 0.0358 0.15 3.66 1.Rachel Carson 1 0.007 0.003 0.16 0.28 0.0036 0.0127 0.0470 0.11 6.2 2. 2 0.009 0.003 0.18 0.38 0.0034 0.0124 0.0556 0.13 7.76 3. 3 0.011 0.003 0.23 0.34 0.0043 0.0141 0.0345 0.26 3.54 1. 4 0.008 0.003 0.23 0.43 0.0028 0.0134 0.0543 0.31 6.21 3. 5 0.011 0.004 0.20 0.32 0.0029 0.0120 0.0417 0.24 3.7 1. 6 0.015 0.007 0.25 0.39 0.0054 0.0213 0.0396 0.35 5.26 2.4 7 0.007 0.003 0.16 0.23 0.0032 0.0117 0.0319 0.13 4.90 1. 8 0.013 0.008 0.18 0.26 0.0042 0.0126 0.0302 0.12 3.74 1.4 9 0.007 0.003 0.18 0.24 0.0031 0.0122 0.0285 0.15 3.88 1.2Zeke's Island 1 0.221 0.123 0.80 0.94 0.0532 0.0675 0.1011 1.41 8.90 3. 2 0.237 0.141 0.78 0.91 0.0479 0.0627 0.1019 1.31 11.44 3. 3 0.186 0.074 0.81 0.85 0.0463 0.0624 0.0855 1.34 3.18 1. 4 0.239 0.150 0.78 0.89 0.0524 0.0697 0.1004 1.53 7.33 2. 5 0.195 0.089 0.77 0.87 0.0463 0.0653 0.0870 1.36 3.95 1.
55

 Appendix C. Summary of sediment contaminant concentrations (dry mass) by analyte at 30 NC NERRS station

that were reported below method detection limits (<MDL) were assigned a value of zero for data analysis purpos

Currituck Banks Rachel Carson Masonboro Sound Z

Analyte Mean Min Max Mean Min Max Mean Min Max Mean Metals (% dry)Aluminum 1.62 0.560 2.86 0.728 0.222 1.86 1.37 0 8.57 2.67 Iron 1.11 0.595 2.03 0.599 0 1.67 0.477 0 1.59 2.06 Trace Metals (μg/g dry mass)

Arsenic 1.87 0.690 3.66 2.41 1.34 5.13 2.89 1.45 8.20 7.99 Barium 167 90.0 205 166 89.0 260 120 84.7 177 163 Beryllium 0.272 01 0.559 0.206 0 0.644 0.202 0 0.71 0.804 Cadmium 0.069 0.021 0.151 0.027 0.011 0.051 0.065 0.044 0.120 0.104 Chromium 23.6 15.9 35.0 16.0 6.96 28.10 17.2 9.18 32.4 29.5 Cobalt 3.39 1.41 5.74 1.70 0.671 3.67 1.24 0.512 2.85 4.63 Copper 1.96 0 5.87 0 0 0 2.57 0 12.8 7.19 Lead 11.9 6.30 19.7 7.45 3.17 13.2 7.32 4.26 14.0 15.2 Lithium 12.6 4.02 26.2 7.59 2.52 23.5 7.47 1.79 24.8 28.2 Manganese 108 72.3 152 67.9 36.9 106 45.9 27.4 74.2 216 Mercury 0.014 0.002 0.037 0.005 0.001 0.017 0.0 0.000 0.0 0.031 Nickel 5.52 1.42 11.3 2.57 0 7.880 2.25 0 7.47 8.94 Selenium 0.185 0 0.509 0.073 0 0.369 0.197 0 0.549 0.487 Silver 0 0 0 0 0 0 0 0 0 0 Thallium 0.238 0.106 0.357 0.171 0.061 0.302 0.180 0.107 0.295 0.256 Tin 1.03 0.551 1.51 0.584 0.198 1.08 0.550 0.245 1.06 1.20 Uranium 1.24 0.746 1.64 0.737 0.451 1.18 1.21 0.925 1.56 1.61 Vanadium 31.2 17.3 49.5 18.5 7.59 36.2 18.8 10.4 37.6 37.6 Zinc 21.2 0 44.9 8.63 0 34.6 9.77 0 43.7 44.5 PAHs (ng/g dry)

Napthalene 0 0 0 0 0 0 0 0 0 4.25 2-MethylNapthalene 0 0 0 0 0 0 0 0 0 0 1-MethylNapthalene 0 0 0 0 0 0 0 0 0 0 biphenyl 0 0 0 0 0 0 0 0 0 0 2,6-dimethylnaphthalene 0 0 0 0 0 0 0 0 0 0 acenaphthylene 0 0 0 0 0 0 0 0 0 0 acenaphthene 0 0 0 0 0 0 0 0 0 0 1,6,7-trimethylnaphthalene 0 0 0 0 0 0 0 0 0 0 flourene 0 0 0 0 0 0 0 0 0 0 dibenzothiophene 0 0 0 0 0 0 0 0 0 0 phenanthrene 0 0 0 0 0 0 0 0 0 0 anthracene 0 0 0 0 0 0 0 0 0 0 
56

Currituck Banks Rachel Carson Masonboro Sound Z

Analyte Mean Min Max Mean Min Max Mean Min Max Mean 1-methylphenanthrene 0 0 0 0 0 0 0 0 0 0 flouranthene 0 0 0 0 0 0 0 0 0 0 pyrene 0 0 0 0 0 0 0 0 0 0 benz(a)anthracene 0 0 0 0 0 0 0 0 0 0 chrysene+triphenylene 0 0 0 0 0 0 0 0 0 0 benzo(b)flouranthene 3.14 0 8.91 3.98 0 12.8 0 0 0 12.9 benzo(j+k)flouranthene 0 0 0 0 0 0 0 0 0 0 benzo(e)pyrene 0 0 0 0 0 0 0 0 0 0 benzo(a)pyrene 0 0 0 0 0 0 0 0 0 0 perylene 6.57 0 16.3 0 0 0 0 0 0 36.1 indeno(1,2,3-cd)pyrene 0 0 0 0 0 0 0 0 0 0 dibenz(a,h)anthracene 0 0 0 0 0 0 0 0 0 0 benzo(g,h,i)perylene 0 0 0 0 0 0 0 0 0 0 TOTAL PAHs 9.71 0.00 25.2 16.6 0.00 67.1 14.9 0.00 106 68.6 PBDEs (ng/g dry)

PBDE 17 0 0 0 0 0 0 0 0 0 0 PBDE 28 0 0 0 0 0 0 0 0 0 0 PBDE 71 0 0 0 0 0 0 0 0 0 0 PBDE 47 0 0 0 0 0 0 0 0 0 0 PBDE 66 0 0 0 0 0 0 0 0 0 0 PBDE 100 0 0 0 0 0 0 0 0 0 0 PBDE 99 0 0 0 0 0 0 0 0 0 0 PBDE 85 0 0 0 0 0 0 0 0 0 0 PBDE 154 0 0 0 0 0 0 0 0 0 0 PBDE 153 0 0 0 0 0 0 0 0 0 0 PBDE 138 0 0 0 0 0 0 0 0 0 0 PBDE 183 0 0 0 0 0 0 0 0 0 0 PBDE 190 0 0 0 0 0 0 0 0 0 0 PCBs (ng/g dry)

PCB 103 0 0 0 0 0 0 0 0 0 0 PCB 104 0 0 0 0 0 0 0 0 0 0 PCB 105 0 0 0 0 0 0 0 0 0 0 PCB 106/118 0 0 0 0 0 0 0 0 0 0 PCB 107/108 0 0 0 0 0 0 0 0 0 0 PCB 110 0 0 0 0 0 0 0 0 0 0 PCB 114 0 0 0 0 0 0 0 0 0 0 PCB 119 0 0 0 0 0 0 0 0 0 0 

Appendix C continued. 
57

Currituck Banks Rachel Carson Masonboro Sound Z

Analyte Mean Min Max Mean Min Max Mean Min Max Mean PCB 12 0 0 0 0 0 0 0 0 0 0 PCB 123 0 0 0 0 0 0 0 0 0 0 PCB 126 0 0 0 0 0 0 0 0 0 0 PCB 128/167 0 0 0 0 0 0 0 0 0 0 PCB 130 0 0 0 0 0 0 0 0 0 0 PCB 132/168 0 0 0 0 0 0 0 0 0 0 PCB 138/163/164 0.20 0 0.44 0.10 0 0.23 0.11 0 0.29 0.34 PCB 141 0 0 0 0 0 0 0 0 0 0 PCB 146 0 0 0 0 0 0 0 0 0 0 PCB 149 0 0 0 0 0 0 0 0 0 0 PCB 15 0 0 0 0 0 0 0 0 0 0 PCB 151 0 0 0 0 0 0 0 0 0 0 PCB 153 0 0 0 0 0 0 0 0 0 0 PCB 154 0 0 0 0 0 0 0 0 0 0 PCB 156 0 0 0 0 0 0 0 0 0 0 PCB 157 0 0 0 0 0 0 0 0 0 0 PCB 158 0 0 0 0 0 0 0 0 0 0 PCB 159 0 0 0 0 0 0 0 0 0 0 PCB 169 0 0 0 0 0 0 0 0 0 0 PCB 170/190 0 0 0 0 0 0 0 0 0 0 PCB 172 0 0 0 0 0 0 0 0 0 0 PCB 174 0 0 0 0 0 0 0 0 0 0 PCB 177 0 0 0 0 0 0 0 0 0 0 PCB 18 0 0 0 0 0 0 0 0 0 0 PCB 180 0 0 0 0 0 0 0 0 0 0 PCB 183 0 0 0 0 0 0 0 0 0 0 PCB 184 0 0 0 0 0 0 0 0 0 0 PCB 187 0 0 0 0 0 0 0 0 0 0 PCB 188 0 0 0 0 0 0 0 0 0 0 PCB 189 0 0 0 0 0 0 0 0 0 0 PCB 193 0 0 0 0 0 0 0 0 0 0 PCB 194 0 0 0 0 0 0 0 0 0 0 PCB 195 0 0 0 0 0 0 0 0 0 0 PCB 198 0 0 0 0 0 0 0 0 0 0 PCB 2 0 0 0 0 0 0 0 0 0 0 PCB 20 0 0 0 0 0 0 0 0 0 0 PCB 200/201 0 0 0 0 0 0 0 0 0 0 PCB 202 0 0 0 0 0 0 0 0 0 0 PCB 206 0 0 0 0.02 0 0.16 0.03 0 0.18 0.26 PCB 207 0 0 0 0 0 0 0 0 0 0 
58

Currituck Banks Rachel Carson Masonboro Sound Z

Analyte Mean Min Max Mean Min Max Mean Min Max Mean PCB 209 0 0 0 0 0 0 0 0 0 0 PCB 26 0 0 0 0 0 0 0 0 0 0 PCB 28 0 0 0 0 0 0 0 0 0 0 PCB 29 0 0 0 0 0 0 0 0 0 0 PCB 3 0 0 0 0 0 0 0 0 0 0 PCB 31 0 0 0 0 0 0 0 0 0 0 PCB 37 0.20 0 0.78 0 0 0 0 0 0 0 PCB 44 0 0 0 0 0 0 0 0 0 0 PCB 45 0 0 0 0 0 0 0 0 0 0 PCB 48 0 0 0 0 0 0 0 0 0 0 PCB 5/8 0 0 0 0 0 0 0 0 0 0 PCB 50 0 0 0 0 0 0 0 0 0 0 PCB 52 0 0 0 0 0 0 0 0 0 0 PCB 56/60 0 0 0 0 0 0 0 0 0 0 PCB 61/74 0 0 0 0 0 0 0 0 0 0 PCB 63 0 0 0 0 0 0 0 0 0 0 PCB 66 0 0 0 0 0 0 0 0 0 0 PCB 69 0 0 0 0 0 0 0 0 0 0 PCB 70 0 0 0 0 0 0 0 0 0 0 PCB 76 0 0 0 0 0 0 0 0 0 0 PCB 77 0 0 0 0 0 0 0 0 0 0 PCB 81 0 0 0 0 0 0 0 0 0 0 PCB 82 0 0 0 0 0 0 0 0 0 0 PCB 84 0 0 0 0 0 0 0 0 0 0 PCB 87/115 0 0 0 0 0 0 0 0 0 0 PCB 88 0 0 0 0 0 0 0 0 0 0 PCB 89/90/101 0 0 0 0 0 0 0 0 0 0 PCB 9 0 0 0 0 0 0 0 0 0 0 PCB 92 0 0 0 0 0 0 0 0 0 0 PCB 95 0 0 0 0 0 0 0 0 0 0 PCB 99 0 0 0 0 0 0 0 0 0 0 Pesticides (ng/g dry)

2,4'-DDD 0 0 0 0 0 0 0 0 0 0 2,4'-DDE 0 0 0 0 0 0 0 0 0 0 2,4'-DDT 0 0 0 0 0 0 0 0 0 0 4,4'-DDD 0 0 0 0 0 0 0 0 0 0 4,4'-DDE 0 0 0 0 0 0 0 0 0 0 4,4'-DDT 0 0 0 0 0 0 0 0 0 0 Aldrin 0 0 0 0 0 0 0 0 0 0 Chlorpyrifos 0 0 0 0 0 0 0 0 0 0 
59

Currituck Banks Rachel Carson Masonboro Sound Z

Analyte Mean Min Max Mean Min Max Mean Min Max Mean Cis-chlordane (alpha-chlordane) 0 0 0 0 0 0 0 0 0 0 Dieldrin 0 0 0 0 0 0 0 0 0 0 Endosulfan I 0 0 0 0 0 0 0 0 0 0 Endosulfan II 0 0 0 0 0 0 0 0 0 0 Endosulfan Sulfate 0 0 0 0 0 0 0 0 0 0 Gamma-HCH (g-BHC, lindane) 0 0 0 0 0 0 0 0 0 0 Heptachlor 0 0 0 0 0 0 0 0 0 0 Heptachlor epoxide 0 0 0 0 0 0 0 0 0 0 Hexachlorobenzene 0 0 0 0 0 0 0 0 0 0 Mirex 0 0 0 0 0 0 0 0 0 0 Trans-nonachlor 0 0 0 0 0 0 0 0 0 0 
60

Appendix D. Summary by station of mean ERM quotients and the number of contaminants that exceeded the co

ERM values (from Long et al., 1995) at 30 NC NERRS stations. 

Station NERRS Site Mean ERM-Q # of ERLs exceeded # of ERMs exceeded Sediment Quality Assessment based on ERL/ERM exceedancesa Sedime

NC06CB01 Currituck Banks 0.003612 0 0 good NC06CB02 Currituck Banks 0.018458 0 0 good NC06CB03 Currituck Banks 0.007425 0 0 good NC06CB04 Currituck Banks 0.009096 0 0 good NC06RC01 Rachel Carson 0.00458 0 0 good NC06RC02 Rachel Carson 0.002653 0 0 good NC06RC03 Rachel Carson 0.004996 0 0 good NC06RC04 Rachel Carson 0.005539 0 0 good NC06RC05 Rachel Carson 0.014272 0 0 good NC06RC06 Rachel Carson 0.004908 0 0 good 

NO06RC07 Rachel Carson 0.002355 0 0 good NO06RC08 Rachel Carson 0.011519 0 0 good 

NC06RC09 Rachel Carson 0.004782 0 0 good 

NC06MI01 Masonboro Sound 0.004966 0 0 good NC06MI02 Masonboro Sound 0.004727 0 0 good NC06MI03 Masonboro Sound 0.008107 0 0 good NC06MI04 Masonboro Sound 0.008873 0 0 good NC06MI05 Masonboro Sound 0.003244 0 0 good NC06MI06 Masonboro Sound 0.00337 0 0 good NC06MI07 Masonboro Sound 0.005015 0 0 good NC06MI08 Masonboro Sound 0.020689 1 0 good NC06MI09 Masonboro Sound 0.015499 0 0 good NC06MI10 Masonboro Sound 0.00422 0 0 good NC06MI11 Masonboro Sound 0.006027 0 0 good NC06MI12 Masonboro Sound 0.003187 0 0 good 

NC06ZI01 Zeke's Island 0.00563 0 0 good NC06ZI02 Zeke's Island 0.036887 1 0 good NC06ZI03 Zeke's Island 0.009127 0 0 good NC06ZI04 Zeke's Island 0.010628 0 0 good NC06ZI05 Zeke's Island 0.035535 1 0 good 

a. Good (low contamination) = < 5 ERLS exceeded and no ERM exceeded; Moderate = ≥ 5 ERLs exceeded and no ERMs excee

contamination) = ≥ 1 ERM exceeded (sensu USEPA 2004). 

b. Good (low contamination) = mean ERM-Q < 0.02; Moderate = mean ERM-Q > 0.02 to 0.058; Poor (high contamination) = m

(sensu Hyland et al. 1999). 
61

Appendix E. Summary by station of Microtox toxicity tests conducted in sediments from 30 NC 

NERRS stations. Stations were determined to be toxic if %EC50 was <0.5 and the silt-clay content 

was <20%, or if the %EC50 was <0.2 and the silt-clay content was >20%. 

Station NC NERRs Site Silt-Clay Content (%) Microtox EC50 Toxic Response (y/n) 

NC06CB01 Currituck Banks 3.24 4.4832 n 

NC06CB02 Currituck Banks 55.7 0.6316 n 

NC06CB03 Currituck Banks 27.54 3.4598 n 

NC06CB04 Currituck Banks 29.69 2.6036 n 

NC06RC01 Rachel Carson 0.59 >16.0950 n 

NC06RC02 Rachel Carson 0.34 >16.6338 n 

NC06RC03 Rachel Carson 8.42 5.3420 n 

NC06RC04 Rachel Carson 0.58 6.5340 n 

NC06RC05 Rachel Carson 46.35 0.1112 y 

NC06RC06 Rachel Carson 11.47 0.8575 n 

NO06RC07 Rachel Carson 0.08 >.16.7856 n 

NO06RC08 Rachel Carson 35.52 0.1729 y 

NC06RC09 Rachel Carson 0.8 11.3830 n 

NC06MI01 Masonboro Sound 10.69 2.3986 n 

NC06MI02 Masonboro Sound 1.79 >16.9245 n 

NC06MI03 Masonboro Sound 13.03 0.2857 y 

NC06MI04 Masonboro Sound 14.65 0.2440 y 

NC06MI05 Masonboro Sound 2.76 >15.3524 n 

NC06MI06 Masonboro Sound 0.31 5.7567 n 

NC06MI07 Masonboro Sound 0.55 3.6188 n 

NC06MI08 Masonboro Sound 44.3 0.1709 y 

NC06MI09 Masonboro Sound 27.09 0.0617 y 

NC06MI10 Masonboro Sound 0.92 13.5398 n 

NC06MI11 Masonboro Sound 8.55 2.3017 n 

NC06MI12 Masonboro Sound 0.17 10.7327 n 

NC06ZI01 Zeke's Island 13.39 2.5966 n 

NC06ZI02 Zeke's Island 72.91 0.0401 y 

NC06ZI03 Zeke's Island 4.52 1.9629 n 

NC06ZI04 Zeke's Island 21.5 0.0889 y 

NC06ZI05 Zeke's Island 66.07 0.0284 y 
62

Appendix F. Summary by station of benthic macroinfaunal (> 0.5mm) characteristics at 30 stations 

sampled in NC NERRS in September 2006. Three replicate benthic grabs (0.04m2

 each) were taken at 

each station. 

NERRS 

Site Station 

Mean # Taxa 

per Grab 

Total # Taxa 

per Station 

Mean Density 

(#/m2

) 

Mean H′

per Grab 

B-IBI 

Score 

Currituck 

Banks 1 5 11 667 1.3 2 

 2 8 16 583 2.3 3 

 3 20 30 5792 2.4 4.5 

 4 15 23 2992 2.5 4.5 

Rachel 

Carson 1 26 56 2317 3.4 4.5 

 2 21 46 2942 3.2 5 

 3 34 67 3308 4.1 4.5 

 4 27 50 3267 3.4 4.5 

 5 24 50 1992 3.6 4 

 6 29 49 3467 3.7 4.5 

 7 17 33 750 3.7 4.5 

 8 41 73 4583 4.2 4.5 

 9 27 54 1900 3.9 4.5 

Masonboro 

Island 1 18 38 1417 2.9 3 

 2 39 73 2500 4.7 4.5 

 3 13 27 1342 2.8 2.5 

 4 6 14 417 1.8 2 

 5 13 22 1058 2.5 3.5 

 6 21 46 1008 4 3.5 

 7 47 85 3608 4.8 4 

 8 6 9 1225 1.4 1.5 

 9 14 29 5200 1.7 2.5 

 10 17 33 1617 2.8 3.5 

 11 40 70 7842 3.4 4 

 12 20 43 1408 3.5 3.5 

Zeke's 

Island 1 12 22 2683 2.1 4.5 

 2 4 8 658 1.3 1.5 

 3 18 30 3508 2.7 4.5 

 4 9 14 3808 2.2 4.5 

 5 2 3 375 0.2 1 
63

Appendix G. Summary of fish tissue contaminant concentrations (wet mass) by analyte and fish 

species at NC NERRS. Concentrations that were reported below detection limits (<MDL) were 

assigned a value of zero for data analysis purposes. 

White Perch Croaker Spot Pigfish Analyte Mean Min Max Mean Min Max Mean Min Max Mean Min Max 

Metals (μg/g wet weight) 

Aluminum 0.969 0.462 1.818 1.42 0.73 2.30 1.89 1.75 2.03 1.01 0.674 1.734 

Arsenic 0.140 0.118 0.153 4.97 0.16 15.63 0.415 0.144 0.686 4.02 1.93 6.04 

Inorganic Arsenica

 0.0028 0.0024 0.0031 0.099 0.003 0.313 0.008 0.003 0.014 0.080 0.039 0.121 

Barium 0.0460 0.0387 0.0579 0.071 0.032 0.236 0.097 0.097 0.097 0.064 0.031 0.115 

Beryllium 0 0 0 0 0 0 0 0 0 0 0 0 

Cadmium 0 0 0.001 0 0 0.002 0 0 0.001 0.001 0 0.002 

Chromium 0.459 0.431 0.495 0.434 0.300 0.560 0.508 0.486 0.529 0.519 0.323 0.858 

Cobalt 0 0 0 0.002 0 0.010 0.009 0 0.018 0 0 0 

Copper 0.288 0.251 0.317 0.343 0.274 0.556 0.331 0.323 0.340 0.448 0.313 0.586 

Iron 10.6 9.4 11.3 11.5 10.2 13.0 25.7 16.2 35.1 12.2 10.8 14.4 

Lead 0.008 0 0.017 0.004 0 0.013 0.007 0.005 0.009 0.086 0.003 0.399 

Lithium 0 0 0 0.007 0 0.019 0 0 0 0.020 0 0.028 

Manganese 0.250 0.202 0.282 0.331 0.243 0.849 0.538 0.288 0.788 0.212 0.138 0.271 

Mercury 0.108 0.090 0.140 0.020 0.009 0.035 0.018 0.012 0.023 0.031 0.019 0.040 

Nickel 0.018 0.013 0.022 0.049 0.010 0.240 0.030 0.027 0.032 0.033 0.024 0.043 

Selenium 0.671 0.603 0.731 0.726 0.527 1.25 0.523 0.502 0.545 0.701 0.518 0.842 

Silver 0 0 0 0 0 0 0 0 0 0 0 0 

Thallium 0 0 0 0 0 0 0 0 0 0 0 0 

Tin 0 0 0 0 0 0 0.009 0 0.018 0 0 0 

Uranium 0 0 0 0 0 0 0 0 0 0 0 0 

Vanadium 0.078 0.067 0.085 0.111 0.060 0.168 0.096 0.064 0.129 0.156 0.124 0.175 

Zinc 11.9 9.2 15.8 4.93 4.22 5.48 7.94 7.68 8.19 5.81 4.99 7.01 

PAHs (ng/g wet weight) 

Napthalene 0 0 0 0 0 0 0 0 0 0 0 0 

2-MethylNapthalene 0 0 0 0 0 0 0 0 0 0 0 0 

1-MethylNapthalene 0 0 0 0 0 0 0 0 0 0 0 0 

biphenyl 0 0 0 0 0 0 0 0 0 0 0 0 

2,6-

dimethylnaphthalene 0 0 0 0 0 0 0 0 0 0 0 0 

acenaphthylene 0 0 0 0 0 0 0 0 0 0 0 0 

acenaphthene 0 0 0 0 0 0 0 0 0 0 0 0 

1,6,7-

trimethylnaphthalene 0 0 0 0 0 0 0 0 0 0 0 0 

flourene 0 0 0 0 0 0 0 0 0 0 0 0 

dibenzothiophene 0 0 0 0 0 0 0 0 0 0 0 0 

phenanthrene 0 0 0 0 0 0 0 0 0 0 0 0 

anthracene 0 0 0 0 0 0 0 0 0 0 0 0 

1-methylphenanthrene 0 0 0 0 0 0 0 0 0 0 0 0 

flouranthene 0 0 0 0 0 0 0 0 0 0 0 0 

pyrene 0 0 0 0 0 0 0 0 0 0 0 0 

benz(a)anthracene 0 0 0 0 0 0 0 0 0 0 0 0 

chrysene+ 

triphenylene 0 0 0 0 0 0 0 0 0 0 0 0 

benzo(b)flouranthene 0 0 0 0 0 0 0 0 0 0 0 0 

benzo(j+k) 

flouranthene 0 0 0 0 0 0 0 0 0 0 0 0 

benzo(e)pyrene 0 0 0 0 0 0 0 0 0 0 0 0 

benzo(a)pyrene 0 0 0 0 0 0 0 0 0 0 0 0 
64

White Perch Croaker Spot Pigfish Analyte Mean Min Max Mean Min Max Mean Min Max Mean Min Max 

perylene 0 0 0 0 0 0 0 0 0 0 0 0 

indeno(1,2,3-cd) 

pyrene 

0 0 0 0 0 0 0 0 0 0 0 0 

dibenz(a,h)anthracene 0 0 0 0 0 0 0 0 0 0 0 0 

benzo(g,h,i)perylene 0 0 0 0 0 0 0 0 0 0 0 0 

PBDEs (ng.g wet weight) 

PBDE 17 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 28 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 71 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 47 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 66 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 100 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 99 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 85 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 154 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 153 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 138 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 183 0 0 0 0 0 0 0 0 0 0 0 0 

PBDE 190 0 0 0 0 0 0 0 0 0 0 0 0 

PCBs (ng/g wet weight) 

Total PCBs 0.359 0.300 0.399 1.98 0.415 4.030 0.990 0.288 1.91 0.555 0.293 0.818 

Pesticides (ng/g wet weight) 

2,4'-DDD 0 0 0 0 0 0 0 0 0 0 0 0 

2,4'-DDE 0 0 0 0 0 0 0 0 0 0 0 0 

2,4'-DDT 0 0 0 0 0 0 0 0 0 0 0 0 

4,4'-DDD 0 0 0 0.096 0 0.675 0 0 0 0 0 0 

4,4'-DDE 0.460 0 0.854 0.902 0 2.605 0 0 0.868 0 0 0 

4,4'-DDT 0 0 0 0 0 0 0 0 0 0 0 0 

Aldrin 0 0 0 0 0 0 0 0 0 0 0 0 

Chlorpyrifos 0 0 0 0 0 0 0 0 0 0 0 0 

Cis-chlordane 

(alpha-chlordane) 0 0 0 0 0 0 0 0 0 0 0 0 

Dieldrin 0 0 0 0.297 0 0.625 0 0 0.625 0 0 0 

Endosulfan I 0 0 0 0 0 0 0 0 0 0 0 0 

Endosulfan II 0 0 0 0 0 0 0 0 0 0 0 0 

Endosulfan Sulfate 0 0 0 0 0 0 0 0 0 0 0 0 

Gamma-HCH 

(g-BHC, lindane) 0 0 0 0 0 0 0 0 0 0 0 0 

Heptachlor 0 0 0 0 0 0 0 0 0 0 0 0 

Heptachlor epoxide 0 0 0 0 0 0 0 0 0 0 0 0 

Hexachlorobenzene 0 0 0 0 0 0 0 0 0 0 0 0 

Mirex 0 0 0 0.088 0 1.061 0 0 0 0 0 0 

Trans-nonachlor 0 0 0 0 0 0 0 0 0 0 0 0 a

. Inorganic arsenic estimated at 2% of total arsenic (USEPA 2000). 

Appendix G continued. 

United States Department of Commerce 

Carlos M. Gutierrez 

Secretary 

National Oceanic and Atmospheric Administration 

Vice Admiral Conrad C. Lautenbacher, Jr. USN (Ret.) 

Under Secretary of Commerce for Oceans and Atmospheres 

National Ocean Service 

John (Jack) H. Dunnigan 

 Assistant Administrator for Ocean Service and Coastal Zone Management