Special Thanks *

About the Environmental Science Laboratory *

1 - Pasquotank River Water Quality Program *

1.1 Purpose of the PRWQ Program *

1.2 Testing Methods of the PRWQ Program *

1.3 Pasquotank River Overview *

2 - Estuaries *

2.1 What is an Estuary? *

2.2 Why protect Estuaries? *

2.3 Threats to Estuaries *

2.4 The Future of Estuaries *

2.5 Albemarle-Pamlico Estuary *

3 - pH *

3.1 What is pH? *

3.2 Synergistic Effects of pH *

3.3 pH in Surface Water *

3.4 pH in the Pasquotank River *

3.5 Test Methods for pH *

4 - Dissolved Oxygen (DO) *

4.1 What is Dissolved Oxygen? *

4.2 Factors that Determine DO *

4.3 DO in the Pasquotank River *

4.4 Test Methods for DO *

5 - Nitrates & Phosphates *

5.1 Effects of Nutrients on Surface Water *

5.2 Nitrates *

5.3 Phosphates *

5.4 Sources of Nitrate & Phosphate Pollution *

5.5 Nitrates in the Pasquotank River *

5.6 Test Methods for Nitrates *

5.7 Phosphates in the Pasquotank River *

5.8 Test Methods for Phosphates *

6 - Microbiology *

6.1 What is total coliform and e.coli? *

6.2 Total coliform in the Pasquotank *

6.3 E.coli in the Pasquotank *

6.4 Continued Coliform Testing *

6.5 Microbiology Test Methods *

7 - Total Dissolved Solids and Conductivity *

7.1 What is TDS? *

7.2 TDS in the Pasquotank *

7.3 What is Conductivity? *

7.4 Conductivity in the Pasquotank *

7.5 Test Methods for TDS & Conductivity *

8 - Temperature *

8.1 How water temperature affects water quality *

8.2 Water Temperature in the Pasquotank *

8.3 Continued Testing *

9 - Conclusion *

9.1 Conclusions in the Pasquotank River *

9.2 Continuation of the PRWQ Program *

9.3 Final Thoughts *

Works Cited *

Contact Information *

This is written in appreciation to the people who contributed their time and shared their knowledge. Thank you for making this a successful project.

First of all, great thanks are owed to Dr. Maurice Powers who is responsible for creating the Environmental Science Research Laboratory. Without his requests for funding, motivation, dedication and hard work none of this would have been possible. Thank you for your inspiration.

Also special appreciation is owed to Dr. James McLean and his staff in Sponsored Programs. The hardworking staff at Sponsored programs always had the answers to the difficult administrative questions, and was always friendly and happy to assist. Thank you for all the administrative support and continued funding.

In addition, many people offered their knowledge and advice. Out of those, a few deserve special recognition. Harold Johnson of the NC DENR’s Division of Marine Fisheries (Elizabeth City Office) offered advice and knowledge, and introduced us to many of the water quality professionals in the region. Also Guy Stefanski and Joan Giordano of the Albemarle-Pamlico National Estuary Program. Their assistance and data sharing was invaluable. They also invited us to attend and present at Albemarle-Pamlico National Estuary Program meetings and workshops.

The Pasquotank River Water Quality Program was initiated in August 1998. The research is based out of the Environmental Science Lab in the Department of Geosciences. The ESL is directed by Dr. Maurice Powers and funded by Title III. The laboratory has a successful track record since its beginnings in 1994. Some of the more successful research and programs have included the Dismal Swamp Boardwalk Project, the Water Quality Hotline, and surface water, ground water and drinking water testing programs.

Students working out of a small, cramped laboratory in the Jenkins Science Center have had a major impact on water quality issues in the area. Many research and work study students have learned about the environment, been taught the procedures for a multitude of water quality tests, and have been challenged to explore new territory through research and investigation. Any problems found are reported to the proper agency and the responsible parties.

The primary purpose of the PRWQ Program was to collect a water quality database for the Pasquotank River over a one-year time period and to use that information to identify any water quality concerns. Data from the Pasquotank River in the past has been either localized to the Elizabeth City area or only tested for a few parameters. A database for the area is clearly needed due to the fact that it will indicate the overall health of the River. A secondary purpose of the program was to monitor the differences between the man-made Dismal Swamp Canal and the Pasquotank River, and to determine if the Canal was having any negative affects on the River.

Ten monitoring stations were set up along the Pasquotank River and the Dismal Swamp Canal (See Location Map, Appendix A). The stations were sampled bi-weekly between the hours of 10:00 a.m. and 3:00 p.m., and weather conditions were observed and noted. Parameters monitored were pH, nitrates, phosphates, dissolved oxygen (DO), temperature, total dissolved solids (TDS), conductivity, and microbiology. Concerns in the Pasquotank River are from mostly non-point sources – runoff from farmland, hog farms, faulty septic tank systems, runoff from lawns, and stormwater runoff from Elizabeth City, the largest populated area on the River (NC DEHNR, 1997). Microbiology is a concern throughout the basin, and pH and dissolved oxygen levels are suspected to be low in the Dismal Swamp area.

The Pasquotank River is located in Northeastern North Carolina, and it forms the boundary between Camden and Pasquotank counties. It is the only water supply watershed in the basin, and the River is fresh above Elizabeth City and brackish and tidally influenced below (NC DEHNR, 1997). It is one of the five major tributaries to the Albemarle Sound, and is a part of the Atlantic Intracoastal Waterway. It is considered a "blackwater river" due to the coloration from tannic acid that leaches into the water from surrounding wetlands. The Pasquotank River and the Albemarle Sound is part of the Albemarle-Pamlico Estuary System, which is one of the largest estuaries in the United States, second only to the Chesapeake Bay.

The Pasquotank River has historically played an important role for the area, providing the basis for Elizabeth City. English settlers came to the Albemarle area from Roanoke Island in 1585. The Pasquotank River became a commercial "water highway", making the area a center for West Indies trade. In 1793, construction of the Dismal Swamp Canal began, which linked the Pasquotank River with the Chesapeake Bay via the Elizabeth River. This is the oldest continually operating man-made canal in the United States. What keeps it alive today is the myriad of pleasure boaters who transit this unique waterway every year on the Atlantic Intracoastal Waterway, which provides a protected inland channel between Norfolk, VA and Miami, Fla. Today the Pasquotank River is more important as a recreational area, with fishing, pleasure boating, swimming and water-skiing being a few of the many activities that attract locals and visitors to the area.

Estuaries are dynamic bodies of water along our nation’s coasts that are formed by the mixing of freshwater from rivers and streams with saltwater from the ocean. Typically these waters are semi-enclosed by surrounding mainland, fringing wetlands, peninsulas or barrier islands. Many terrestrial and aquatic species inhabit estuarine areas. The constant interchange of nutrients and the availability of sunlight in estuaries make these waters prime habitat for aquatic life. (Martin & others, 1996)

Estuaries and adjacent lands support a variety of habitats for plants and animals. Distinctive estuarine habitat types include eelgrass beds, seagrass beds, kelp beds, mangrove forests, salt marshes, freshwater marshes, upland forested wetlands, etc. Lobsters, shrimp, crabs, oysters, scallops and clams are examples of shellfish that depend on estuarine systems. Estuarine dependent finfish species include menhaden, cod, flounder, spotted seatrout, mullet, and striped bass. In addition anadromous fish (species that migrate from ocean to freshwater streams in order to spawn), such as salmon, shad, and alewife use estuaries during their migrations. Colonial waterbirds, shorebirds, songbirds, seabirds, waterfowl and raptors use estuaries and estuarine wetlands for a variety of purposes, including breeding, nesting, and foraging. In addition, estuaries provide feeding and resting points during bird migrations. Also many marine and terrestrial mammals inhabit estuarine areas. (Martin & others, 1996)

Estuaries are the life force of the oceans. Serving as the transition zone between the land and the sea. The intermixing of fresh and saltwater in this transition zone creates a distinct environment where aquatic communities thrive. An abundance of land and ocean nutrients, ample light which promotes the growth of aquatic vegetation, and a continuous mixing of the system by winds, tides and river inflows create conditions which give life to some of the richest and most productive ecosystems in the world. Amazingly, they produce more food per acre than the most productive mid-western farmland. Almost 75% of all fish and shellfish in the US use estuaries as primary habitat, or as spawning or nursery grounds (Martin & others, 1996). This gains added significance when you realize that commercial and recreational fishing contributes $111 billion to the national economy and 1.5 million jobs (EPA NEP, 1998).

In addition, estuaries and their fringing wetlands play important roles in flood and erosion control, pollution filtration, water quality protection, wildlife conservation, fish production, coastal storm protection, and recreation.

Plants along the shoreline of estuaries and their tributaries trap sediments, nutrients, toxic chemicals, pathogens, and other contaminants carried by water flowing into the wetland area. The contaminants eventually settle into the soils and are neutralized. By reducing the amounts and concentrations of contaminates, these natural areas protect the estuary’s water quality, habitat and wildlife (Martin & others, 1996).

Estuaries also support many filter-feeding organisms that help maintain clean waters. A healthy population of filtering organisms, such as oysters, clams and mollusks contribute significantly to water filtration. One oyster for example, while feeding on plankton, filters 25 gallons of water per day, or 27,375 gallons in a four-year life span (Martin & others, 1996).

Wetland areas protect inland areas from storms and flooding. They act as natural buffers that minimize the impacts of coastal storms and wind on coastal and inland areas. Wetlands have the capacity to temporarily store large quantities of floodwaters, releasing waters over an extended period of time into groundwater and adjacent waterbodies.

The allure of these areas jeopardizes their health and productivity. To support growing populations along the coasts, estuaries are frequently overused and misused by society. Over 45% of the nation’s population reside in estuarine areas (Martin & others, 1996). This percentage is expected to grow over the next few decades. Unfortunately, estuaries are disposal sites for human and industrial wastes, are dredged to create navigational routes for large ships, supply cooling waters needed by power generation plants and other industrial operations, and receive various contaminants that stormwater picks up from streets, lawns, and construction sites. Estuarine wetlands are destroyed in order to open up areas for more shoreline development. The floors of estuaries are damaged by the accumulation of sediments, toxins and nutrients and by the dumping of dredged materials.

Estuaries are adaptable ecosystems. However, they have not been able to adapt to the human impacts associated with rapid development and population growth. Because of their shallow depths and limited circulation, estuaries are highly susceptible to environmental degradation. Throughout the nation, degraded estuaries have led to the loss of commercial fishing jobs, closed shellfish harvesting areas, oxygen-depleted algal blooms and subsequent fish kills, and increased coastal storm damage due to the loss of wetlands. The misuse and overuse of estuaries are threatening the viability of these ecologically and economically valuable waters. Fortunately more and more people are beginning to realize the importance estuaries hold to out country. Organizations like the National Estuary Program are leading the struggle to preserve our estuaries for future generations to enjoy.

The Pasquotank River is located in the Albemarle-Pamlico Estuary, which is the second largest estuary in the United States. The system is made up of seven sounds – Albemarle, Pamlico, Currituck, Croatan, Bogue, Core and Roanoke. It also includes five major river basins, as well as beaches, marshes, and bottomland forests. The Sounds contain approximately 3,000 square miles of estuarine waters. They are relatively shallow with an average depth of 13 feet. The estuary is 26 feet at its deepest point. The watershed area of the Sounds measures 30,000 square miles and includes portions of 36 counties in NC and 16 counties in SE Virginia. (NC DEHNR, 1997)

Almost 2 million people live in this massive watershed, which covers approximately one third of the land area in NC. The watershed includes almost 9,300 miles of freshwater rivers and streams. Groundwater sources and 5 major rivers – the Chowan, Roanoke, Pasquotank, Tar-Pamlico, and Neuse Rivers – deliver fresh water to sounds. A chain of barrier islands, with only a few inlets, separates the Sounds from the Atlantic Ocean. Various types of habitat can be found within the watershed, including pocosins, pine savannas, hardwood swamp forests, bald cypress swamps, salt marshes, brackish marshes, freshwater marshes, and submerged aquatic vegetation. It is one of the most biologically productive estuaries in the US. The Sounds support numerous species of wildlife, fish, shellfish, and plants. The watershed includes 11 National Wildlife Refuges including the Great Dismal Swamp in the vicinity of the Pasquotank River.

A variety of recreational activities attract millions of visitors to the Albemarle-Pamlico Sounds each year. 10% of the local work force is employed by the tourism industry of the Sounds. The populations of the counties increase significantly with tourists during the summer months. More than 60% of the recreational fish in North Carolina use the Sounds for spawning and nursery grounds. In 1991, recreational fishing in North Carolina generated approximately $1.3 billion in economic output and employed nearly 22,000 people. (NC DEHNR, 1997)

In 1987 the Albemarle-Pamlico Estuarine Study (APES) began examining the water quality and habitat problems of the sounds and the impact that the greater watershed area has on the estuarine system. Their research identified habit loss and water quality declines caused by pathogen contamination, toxic pollution, and nutrient loading as the foremost problems affecting the health of the Sounds. Agricultural runoff, storm-water discharges, and runoff from construction sites and forested lands are significant sources of the habitat degradation and pollution currently plaguing the system. North Carolina is the leading meat producer in the nation. Inadequately treated hog wastes has become a particular concern as of late because of the increasing number of hog farms in NC, and the impact their wastes have on estuaries and their tributaries. More than 75% percent of the hog population is raised in the 15 coastal counties (NC DEHNR, 1997).

The state of NC has lost almost 50% of its original 11 million acres of wetlands (Martin & others, 1996). The dramatic rate of population growth and development in the region presents great obstacles to the restoration of the Sounds. In addition to the demands placed on the estuary by the growing number of residents, millions of tourists visit the Sounds each year. Increased population places greater demands on freshwater resources in the region. Specifically, the expanding use of groundwater by businesses, farms and residents in the watershed is depleting the aquifers which feed the Sounds with freshwater.

pH is the measure of the relative acidity or alkalinity of water. The pH is defined as the negative logarithm of the concentration of the hydrogen ion, pH = -log [H₃O+] (Jones & others, 1987). The pH scale describes the acidity of a solution. The pH scale runs from 0 to 14. A pH of 7 indicates a neutral solution (such as pure water), a pH below 7 indicates an acidic solution, and a pH above 7 indicates a basic solution. For each unit decrease in the pH number, there is a tenfold increase in the concentration of the hydrogen ions (that is, the acidity). For example, water with a pH of 5 is ten times more acidic than water with a pH of 6.

As stated, the pH scale is used to determine whether a substance is acidic or basic. In 1923, J.N. Bronsted and T.M. Lowry defined acids and bases as chemists generally recognize them today (Jones & others, 1987).

• Acid – a chemical species that can donate hydrogen ions ( H+ ).
• Base – a chemical species that can accept hydrogen ions.

In the reaction of an acid with a classic base, the acid supplies hydrogen ions, H+, which react with hydroxide ions, OH-, from the base to form water, HOH.

The balance of positive hydrogen ions (H⁺) and negative hydroxide ions (OH^-) in water determines how acidic or basic the water is. When analysts measure pH, they are determining the relative concentration (expressed in exponential, or "power" form) of hydrogen ions; the term "pH" comes from the power of Hydrogen ions, strongly acidic) to 14 (high concentration of negative hydroxide ions, strongly basic). In pure water, the concentration of negative hydrogen ions is in equilibrium with the concentration of negative hydroxide ions, and the pH measures exactly 7.0.

Synergy is the process whereby two or more substances combine and produce effects greater than their sum. For example, 1+1=2 (mathematically). Synergistically 1+1= more than 2.

When acid waters (with low pH) come into contact with certain chemicals and metals, they often make them more toxic than normal. As an example, fish that usually withstand pH values as low as 4.8 will die at 5.5 if the water contains 0.9 mg/L of iron (Hach Company, *²). Mix an acid water environment with small amounts of aluminum, lead or mercury, and you have a similar problem – one far exceeding the usual dangers of these substances.

Most fish can tolerate pH values of about 5.0 to 9.0. The vast majority of American rivers, lakes and streams fall within this range, though acid rain has compromised many bodies of water in our environment.

pH changes to surface waters can result from point and non-point source discharges. The NC standard for pH in fresh water is from 6.0 – 9.0. The supplemental ‘swamp’ (Sw) classification is applied to waters that have naturally acidic waters and allows for lower pH levels (NC DEHNR, 1997). Since pH is naturally low in Sw classified waters, these pH violations do not indicate a man-induced problem.

Acids formed from sulfur oxides can be leached from the air by rain or snow and produce precipitation with a pH below 7. Rain is slightly acidic because of dissolved carbon dioxide, which forms carbonic acid in water and produces a pH of 5.6. Any precipitation below 5.6 is considered acid rain.

As organic substances decay, carbon dioxide (CO₂) forms and combines with water to produce a weak acid, called "carbonic" acid ----- the same stuff that’s in carbonated soft drinks. Large amounts of carbonic acid lower water’s pH.

The data for pH levels in the Pasquotank River were analyzed for changes over time and by station locations. First, the pH readings for each month were averaged to indicate variations (Fig 3.2). The average pH in the Pasquotank River in November and December of 1998 was in the 7.0 range. In January the pH dropped down to an average of just above 6.0, and has remained the same since.

The pH readings for each station were averaged to indicate which locations have characteristically lower pH levels (Fig 3.3). The pH upstream of Elizabeth City at stations 1-4 have been lower than downstream, and climbs from a low of ~5, climbing up to ~7 downstream past Elizabeth City at stations 8 - 10. The acidic readings in the Dismal Swamp Canal at stations 1 and 2 is probably due to tannins leached into the River by the groundwater in the surrounding swamp, which has characteristically low pH levels.

Overall the pH levels found in the Pasquotank River do not indicate a problem. The pH is low in and near the Dismal Swamp Canal, but the lower pH levels are most likely caused by natural occurrences, and not due to acid rain or other pollutants.

pH in the Pasquotank River was tested using the Hach One Portable pH meter made by Hach Company. The pH meter uses a probe to measure pH levels. It provides direct digital readouts in pH units and also indicates temperature of the sample(Hach, 1989 *⁴). Testing was conducted at the lab, immediately on return from the field. Before each set of samples was tested, the probe was calibrated using buffer solutions known to have a pH of 4.00 and 7.00. After calibration, the probe was inserted into a beaker containing 40 ml of the sample, and a reading was taken and recorded.

Since it is required to support aquatic life and maintain water quality, oxygen is the most important dissolved gas in water. Water in equilibrium with air at 25°  C contains 8.3 mg/L of dissolved O₂ (Jones & others, 1987). Although water molecules contain an oxygen atom, this oxygen is not what is needed by aquatic organisms living in natural waters. A small amount of oxygen, up to ten molecules of oxygen per million of water, is actually dissolved in water (Swaddle, 1997). Fish and zooplankton breath dissolved oxygen, and without sufficient oxygen mortality will occur.

DO concentrations are affected by a number of factors. Higher DO is produced by turbulent actions such as waves, which mix air and water. Lower water temperatures also allows for retention of higher DO concentrations. Low DO levels tend to occur more often in warmer, slow moving waters. In general, low DO levels occur during the warmest summer months and particularly during low flow periods. Water depth is also a factor. In deep slow moving waters DO concentrations may be high near the surface due to wind action and plant photosynthesis, but may be entirely depleted (anoxic) at the bottom.

Oxygen consuming wastes include decomposing organic matter or chemicals that reduce DO in the water. Raw domestic wastewater contains high concentrations of oxygen consuming wastes that need to be removed before it can be discharged into a waterway. Maintaining a sufficient level of DO in water is critical to most forms of aquatic life.

• Waste Water Treatment Plant (WWTP) effluent
• Decomposition of organic matter

• Organic waste discharged into water

Over time the average DO concentration for the River fluctuated between 8 – 10 mg/L, except in April when it dropped to an average of ~7.0 mg/L (Fig 4.2). During the time periods tested in April, a large amount of pollen was observed in some parts of the River, floating on the surface. Decomposition of this pollen may have used up oxygen in the water and thus contributed to the low readings in the Pasquotank River.

DO was also analyzed in the Pasquotank River by stations (Fig 4.3). Average levels in the Pasquotank River are lower upstream of Elizabeth City near stations 1-4. This is to be expected due to the low rate of flow, small surface area which prevents turbulent action, and darker water coloration which prevents light from penetrating to the bottom. Still levels were on average around 6.5 – 8.5 mg/L which is sufficient to support aquatic life. Upstream of Elizabeth City where the River widens, the DO concentrations increased to an average of 9 – 10 mg/L. The larger surface area affected by wave action, flow induced by wind tides, and lighter color water which allows more sunlight for photosynthesis all could be contributing factors to account for the higher concentrations.

Overall, DO concentrations in the Pasquotank River seem to be sufficient during the time periods tested. Testing will continue over the warmer summer months to see if the temperature increase will raise levels in the River.

DO in the Pasquotank River was tested using the Model 85 Hand Held Dissolved Oxygen Meter made by YSI. The YSI Model 85 comes with its own calibration chamber, for easy on site calibration (YSI). After calibration the probe was lowered into the water by its 10-ft. cable, and readings were taken near the bottom, the middle and the top of the water’s surface. Usually the readings were the same due to the fact that depth of the water in most testing sites was no more than 5 feet deep. When a difference occurred at different depths, all were recorded. For purposes of this report, the 3 readings were averaged to obtain an overall DO reading for that station.

Nutrient over-enrichment is a leading problem in our nation's estuaries. Low natural concentrations of nitrogen and phosphorus enable algae and phytoplankton to grow. Excessive loadings of nitrates and phosphates introduced by humans are significantly upsetting the balance of estuarine life. An excessive level of nitrogen and phosphorus stimulates the intense growth of algae. The algae under these conditions may grow so densely as to block sunlight needed for the growth of submerged aquatic vegetation. Furthermore, after the algae die, their decomposition requires a great amount of dissolved oxygen. This depletes DO levels for other aquatic life. The resulting low oxygen (hypoxia) and no oxygen conditions can sometimes lead to massive fish kills. (Martin & others, 1996)

In surface waters, Nitrate-Nitrogen levels below 90 mg/L, and nitrite levels below 0.5 mg/L seem to have no effect on warm-water fish (Hach *²). The recommended maximum phosphate-phosphorus level for rivers is 0.1 mg/L (Hach *²).

Nitrogen makes up about 80% of the air we breath (Hach *²). As an essential protein component, it is found in the cells of all living things. Inorganic nitrogen may exist in the free state as a gas, or as nitrites, nitrates or ammonia; organic nitrogen is found in proteins and other compounds. Nitrogen is recycled continually by plants and animals.

Although N² is also the most abundant gas in the atmosphere, plants cannot use nitrogen in this form. They need it in the form of NO₃^-, or nitrates. Nitrogen-fixing bacteria have the ability to "fix" the nitrogen (change to a useful form) by combining it with hydrogen to make ammonia (NH₃), some of which combines with H⁺ in water to become ammonium (NH₄⁺). Nitrite-forming bacteria combine ammonia with oxygen forming nitrites (NO₂^-). The nitrite forming bacteria convert nitrites to nitrates (NO₃^-) (Cunningham, 1994). Now nitrogen is in a form that can be absorbed and used by green plants.

Phosphates exist in three forms: orthophosphate, metaphosphate (or polyphosphate) and organically bound phosphate. Each compound contains phosphorus in a different chemical formula. Ortho forms are produced by natural processes and are found in wastewater. Poly forms are used for treating boiler waters and in detergents; they can change to ortho form in water. Organic phosphates are important in nature and also may result from the breakdown of organic pesticides that contain phosphates.

The usual mineral source of phosphorus is insoluble rock phosphate [Apatite - Ca₅(PO₄)³(F₃OH)] (Swaddle, 1997).

Phosphorus is essential for plant growth and is often the limiting nutrient in aquatic ecosystems. Phosphates are used in fertilizers, pesticides, industry and cleaning compounds. Unlike the nitrogen cycle, the phosphorus cycle is said to be imperfect because not all phosphates are recycled.

Nutrients enter waterways through municipal WWTP effluent, leaky septic systems, animal wastes, agricultural runoff, stormwater containing crop and lawn fertilizers, and atmospheric deposition.

Nitrogen in atmospheric deposition originates primarily from combustion of fossil fuels such as oil and gas. Large industries and automobiles are the two main contributors to atmospheric deposition. Some may settle in particles and some will enter the water by precipitation. This source of pollution is found mostly in industrial and metropolitan areas, and is not believed to be a major source of pollution in Northeastern North Carolina.

WWTP effluent and leaky septic tanks both may be sources of nutrient discharge into rivers and streams. The WWTP in Elizabeth City is a newer facility and claims to meet state and EPA standards for nutrient discharge. Some water quality professionals have voiced some concern about the sewer lines in the area, and there is definitely a strong opinion that many of the septic tanks in Pasquotank and Camden Counties may be failing. This would also be a source of bacterial contamination of the River.

Runoff from agricultural fertilizers is thought to be a major source of nutrient discharge into rivers and streams in the Southeastern United States. On an annual basis, about 11.5 million tons of nitrogen is applied as commercial fertilizer for agricultural purposes in the US (Puckett, online). A portion applied to fields returns to the atmosphere as ammonia gas, and the rest is either taken up by plants or converted to nitrate in the soil. Most of the dissolved nitrogen that enters water from agricultural runoff occurs as nitrate. Also nearly all fertilizers contain phosphates.

Another major source of nutrient over loading in the Southeastern states is runoff from animal farming operations such as hog farms. Each year the 7 billion farm animals in the country produce millions of tons of manure, rich in nutrients (Puckett, online). North Carolina is the leading meat producer in the country, with a large volume of hog farming operations. Hog farm waste lagoons have been a serious concern for pollution of surface and groundwater supplies with nutrients as well as bacteria.

Nitrate overloading does not seem to be a problem in the Pasquotank River from November to May. In surface waters, Nitrate-Nitrogen levels below 90 mg/L seem to have no effect on warm-water fish (Hach *²). The highest nitrate level recorded was 3.5 mg/L in mid January 1999 at station 6 (see Fig. 5.1). The highest monthly average for a station was 2.8 mg/L which was recorded for station 3 in March of 1999 and station 7 for April of 1999. The overall station average for the period between November 1998 and May 1999 ranged from 0.5 mg/L to 1.2 mg/L. The overall monthly average ranged from a low of 0.3 mg/L to a high of 1.2 mg/L. No trends were observed by month or by station to indicate a specific area or time of concern. In addition, no algal blooms or other obvious signs of nutrient overloading was observed. The increased levels of nitrate found erratically during the observation will be looked at more closely, and compared to precipitation data in the region for possible correlation to agricultural runoff.

The method used to test nitrates in the Pasquotank River was Hach Company's Mid Range Cadmium Reduction method (method #8171) using the DR4000 Spectrophotometer. Complete steps to this test can be seen by referring to appendix B. The test read results as NO₃^- -^N , or nitrate nitrogen. Before each set of tests, a reagent blank was determined, and calibration with a known standard was performed.

The recommended maximum phosphate-phosphorus level for rivers is 0.1 mg/L (Hach *²). Most readings in the River were above this limit, with the highest recorded monthly reading being 1.70 mg/L at station 10 during the month of November, 1998 (see Fig 5.2). November also had the highest monthly average of 0.49 mg/L (see Fig 5.3), but this average was due to the aforementioned reading at station 10, and a another high reading at station 8. No specific trends were observed by location or date as readings were erratic. Also no algal blooms were noted in locations with high levels. The phosphate levels will continue to be observed over the summer, and any suspected correlation with agricultural runoff will be investigated.

The test used was Hach Company's Reactive Phosphorus (Orthophosphate) Ascorbic Acid Method (method #8048) using the DR4000 Spectrophotometer. Complete steps to this test can be seen by referring to appendix C. The test read results as PO₄^3- , or orthophosphate. Before each set of tests, a reagent blank was determined, and calibration with a known standard was performed.

Total coliform bacteria are a collection of relatively harmless microorganisms that live in large numbers in the intestines of man and warm- and cold-blooded animals. They aid in the digestion of food. Total coliform bacteria can also be found in various soils and their presence is common to decaying plant material. A specific subgroup of total coliform is the fecal coliform bacteria. The fecal group is associated exclusively with the intestinal tracts of warm-blooded animals. The most common member of the fecal coliform family is Escherichia coli. or e.coli.

Testing for total coliform bacteria is quite important when determining overall water quality. The reason we test for total coliform bacteria in the Pasquotank is not because this easily killed group poses a threat itself. The occupancy of total coliform bacteria within the Pasquotank may indicate the presence of other disease causing organisms. Being such an easily killed organism, its presence raises a question as to what other substances are present and do they pose a health threat? Below is a chart that expresses acceptable amounts of total coliform depending on usage of water.

The graph shows that total coliform levels have been above desirable levels for commercial boating since mid-December:

E.coli bacteria, the head of the large enteric bacteria family, has made headlines as of late because of the amounts of contaminated beef discovered around the country and the illness it has caused. As mentioned above e.coli is a specific type of fecal coliform bacteria which originates in the intestines of warm-blooded organisms. So of what concern does e.coli have with respect to water quality? The Pasquotank River is Elizabeth City's main source of water recreation. Locals fish, boat, and swim in this body of water and the presence of harmful pathogens can have negative affects. E.coli is responsible for three types of infections in humans: urinary tract infections, neonatal meningitis, and intestinal diseases. In fact, e.coli is responsible for 90% of the urinary tract infections in anatomically normal, unobstructed urinary tracts (Todar, online). Since e.coli can come from only one generalized source, the intestinal tracts of warm-blooded animals, one must consider how this potentially harmful microorganism could possibly enter the Pasquotank.

The number one blame seems to be from non-point source runoff. That is runoff of storm waters from the urban areas and even from the wooded areas which surround the river itself. Fecal material from animals such as deer, fox, opossum, squirrels, and even birds is caught up in rain water and delivered downhill into the streams and finally the Pasquotank. The problem with this theory is that our wooded areas act as riparian buffer zones. True non-point source runoff is carried directly into the river without a natural obstacle to hinder it's flow or use up nutrients. Most fecal material from wooded areas has a hard time making it to a stream due to the vast vegetation. The trees, leaves, and vegetation debris on the ground greatly reduce the amount of water that gets to the stream. As the water moves more slowly it either seeps into the groundwater or is transpired by the plants. Without a host to keep the temperature up the e.coli will die before it reaches the surface water.

A more likely reason for elevated e.coli counts is faulty septic systems and/or sanitation practices. The following graph suggests a trend:

Station 5 is located at Roanoke Bible College. This site is just down stream of Elizabeth City's Wastewater treatment facility. The station average is much greater here than at any other site tested. This site, with its lack of heavy vegetation, is also conducive to seagull and duck activity. The highest totals were noted after heavier rainfalls. In addition to Station 5, Stations 6, 9, and 10 all possess certain characteristics. Each station lacks heavy vegetation. Each is location is fairly urbanized or settled. Each of these three sites has been noted as to having water fowl frequent the area. The one item that sets station 5 apart from the other two is that it is located just down stream from the Wastewater Treatment Plant. The Plant's treatment process boasts very low coliform counts. If a containment problem is a possibility then there has been no report of it. Heavy precipitation could aid in the over flow untreated water, if that were the case. The graph below expresses a chronological e.coli distribution in the Pasquotank on a monthly basis:

The count of e.coli peaked in the month of January. Ironically the month of January also provided the coolest water temperatures. This came as a surprise. E.coli counts are typically directly related to temperature. That is, the higher the outside or water temperature, the higher the e.coli count. The end of January is the time when the greatest concentrations of e.coli were measured at station 5. This is the only time and place where e.coli counts really spiked. Counts at this time and location were ten times that of any other during the course of this research. Counts were well over ten times greater than at any other station.

Total coliform and e.coli pose reasonable threats to public health. Attention needs to be drawn to this problem before it gets out of hand. Local health officials need to make it a point to extend public awareness and provide preventative measures. Advertising safer sanitation practices and enforcing stricter laws that cover septic systems and wastewater treatment practices. The Pasquotank River Water Quality Program at ECSU is committed to monitoring the quality of our surface waters. Hopefully this research will provide a base of data that can be referred to in the future.

The m-ColiBlue24 broth membrane filtration technique is used when testing for coliform. Refer to Appendix D for this analytical procedure as explained by Hach.

Total Dissolved Solids (TDS) is a term used to define the amount of all the dissolved minerals in the water. The term solids came from the original method of testing which consisted of evaporating the filtered water and weighing the actual solids that remained. TDS are picked up by the water as it passes over or through the earth. Various rocks that line the course of travel are continuously eroded and their minerals are slowly dissolved by the water. TDS testing is also an indicator of how much salt is dissolved in the water. The TDS measurement expresses the concentration of various ions. In lieu of the evaporation method mentioned above, a conductivity probe was used in the measurement of TDS in this research. The conductivity probe does not record the presence of specific ions, but the total concentration of all inorganic material within the water sample. The conductivity probe was calibrated with sodium chloride solution so that TDS is expressed in PPM (parts per million) of NaCl. (Hach, 1989*³)

The primary inorganic ions that make up TDS are Calcium (Ca⁺⁺), Magnesium(Mg⁺⁺), Sodium(Na⁺), Iron(Fe⁺⁺), Manganese(Mn⁺⁺), Bicarbonate(HCO₃^-), Chloride(Cl^-), Sulfate(SO₄^--), Nitrate(NO₃^-), and Carbonate(CO₃^--). TDS is an indicator of the mineralized character of the water. Heavily mineralized water, AKA hard water, is the most common complaint of residential water. This is due to it’s tendency toward bad taste, scaling, spotting of dishes, and a producing a laxative effect (Culligan,online). One main concern with TDS is how it effects our surface waters. Fish cannot thrive if hardness levels are too high. The hard water is difficult to process. The fish not only filter the oxygen out of the water but they also extract heavy minerals. This ultimately leads to an overdose of those minerals that finally kill the fish.

A trend tends to develop as the winter season moves forward. The TDS measurements peak in December and suddenly drop going into January. This level stays relatively level through March and begins to tail off as we head into the spring. Continued research through out the rest of the year will provide an overall trend of TDS in the Pasquotank River. The presence of fertilizer runoff and runoff of the area’s hard groundwater, which is used extensively for irrigation, may account for some of the TDS.

Total Dissolved Solids are of concern to overall water quality due to salinity concentrations. If the concentrations of TDS become too high then it may pose a threat to normal freshwater life and to agriculturally based outfits. Salinity increases as one moves from the freshwater of the Pasquotank River toward the brackish water of the Albemarle Sound. Higher concentrations of TDS (salinity) could prove useful to organisms that thrive on brackish waters. The boundary that separates freshwater and brackish water food webs could become vague as it moves upstream. These concentrations collect downstream, but if the amount of TDS becomes a problem then that boundary could slowly migrate upstream. The mineral content of water progressively increases as rainfall and runoff coalesce into streams and rivers.

Conductivity is an approximate measure of Total Dissolved Solids. Conductivity is the measurement of a solution’s ability to conduct an electrical current. Absolutely pure water is actually a poor electrical conductor. It is the dissolved substances (salts) within the water which determine how conductive the solution will be. Therefore, conductivity is an excellent indicator of water quality.

The quality of river water is of most importance to everyday operations within the Albemarle region. Environmental conditions such as drought, changing seasons, heavy rainfall, etc. can cause the concentration of dissolved salts in our surface waters to vary significantly. These dissolved salts can affect the health of submerged aquatic vegetation over time. This would ultimately carry the trend through out the food web.

When moving down stream from Station 1 toward Station10, conductivity gradually increases. Above Elizabeth City the more acidic waters that originate out of the Dismal Swamp contain much less in the way of dissolved ions. The number of ions suspended in the surface water increases as it flows past Elizabeth City and closer to the brackish water of the Albemarle Sound. A slight drop is recorded from Station 9 to Station 10. Wind currents will typically drive waters toward the east of the Pasquotank producing slightly higher measurements on the Camden side.

After water samples are collected they are brought back to the ERL for testing. Levels are measured with the Model 44600 Conductivity/TDS Meter manufactured by HachÔ . Conductivity is expressed in millisiemens (a siemen is the reciprocal of the ohm in the resistance measurement) per centimeter (mS/cm). TDS is expressed as grams per liter (g/L). The probe is turned on and lowered into the water sample. The Hach meter automatically makes an adjustment to compensate for temperatures that deviate from the reference temperature of 25^oC.

The determination of conductivity is performed by measuring the resistance occurring in an area of the test solution defined by the design of the probe. A voltage is applied between the two electrodes immersed in the sample, and the voltage drop caused by the resistance of the solution is used to calculate its conductivity per centimeter.(Hach, 1989*³)

Hach uses a factor of 0.5 in the measurement of TDS. That is to say that the testing of TDS is essentially the same as the conductivity procedure. With the introduction of the 0.5 factor, which is nearly equivalent to a sodium chloride concentration, the TDS value is one half the conductivity value. This procedure measures the sum total of the inorganic concentrations within the water sample.(Hach, 1989*³)

Water temperature is probably one of the easily measured aspects of overall water quality. It is also one of the most important. Fish and most aquatic organisms are cold-blooded. Therefore their metabolism increases as the water warms and decreases as it cools. Fish are quite sensitive to water temperature. If the temperature increases or decreases by just a few degrees Celsius, the fish will swim to another area to regulate their body temperature. Fish cannot survive temperatures below 0^oC(32^o F), and very few can tolerate temperatures above 36^oC (97^oF). Dissolved oxygen levels are also linked to water temperature. As water temperature increases, more dissolved oxygen is needed to maintain aquatic life. As water temperature increases by 20^o Celsius, fish need up to six times more dissolved oxygen in the water (Hach, online *²). In other words, if high water temperature is coupled with low dissolved oxygen levels, then it becomes dangerous to aquatic plants and animals.

As noted by the curves, the temperature in the Pasquotank River hasn’t fallen below 5^oC, nor did it rise above 19^oC on average since November. The station to station average has remained fairly consistent, hovering between 9^oC and 12^oC. This is primarily cold weather data. The collection of cold weather data is important so that a correlation can be made based upon seasonal activities, such as farming. More testing will be done as the year moves on. The summer months will be an adequate indicator of just how warm the water will get. For the most part a river's temperature is determined mainly on its locale. The temperature may also depend on a variety of other factors. Below is a list of variables that may affect the temperature of surface water.

1. The color of the water. Most heat warming surface waters comes from the sun, so waterways with dark-colored water, or those with dark muddy bottoms, absorb heat best.
2. The depth of the water. Deep waters usually are colder than shallow waters simply because they require more time to warm up.
3. The amount of shade received from shoreline vegetation. Trees overhanging a lake's shoreline or a river-bank shade the water from sunlight. Some narrow creeks and streams are almost completely covered with overhanging vegetation during certain times of the year. The shade prevents water temperatures from rising too fast on bright sunny days.
4. The latitude of the waterways. Lakes and rivers in cold climates are naturally colder than those in warm climates.
5. The time of year. The temperature of waterways varies with the seasons.
6. The temperature of the water supplying the waterways. Some lakes and rivers are fed by cold mountain streams or underground springs. Others are supplied by rain and/or surface run-off. The temperature of the water flowing into a lake, river or stream helps determine its temperature.
7. The volume of the water. The more water there is, the longer it takes to heat up or cool down.
8. The temperature of effluents dumped into the water. When people dump heated effluents into waterways, the effluents raise the temperature of the water. (Hach, online *²)

The chart below lists the optimum temperatures of common local fishes with respect to their life cycle. Accompanied are two graphs that express average water temperatures monthly and by station.

Temperature is an important tool in determining water quality. It's variation affects the degree to which certain chemicals effect aquatic plant and animal life. By keeping track of the river's changing temperature trends in water quality may be noted. Tracking the Pasquotank's water temperature will remain protocol for the PRWQP.

The Pasquotank River data indicates that the river has good water quality during the winter months, except for the high levels of coliforms and e. coli. Previous microbiological research during the summer months suggest that the levels will increase during the warmer periods. Possible sources in the Pasquotank River are agricultural runoff, stormwater runoff, leaky septic systems, WWTP effluent and local pig farming operations. Further research must be conducted to locate the sources of this contamination, and work must be carried out to find a viable solution.

The PRWQ Program will continue until January of 2000. The completed database will be analyzed for any changes over time and location, and differences between summer and winter recordings will be noted. Also special research over the summer will try to correlate rain fall events to changes in the water chemistry of the Pasquotank River.

The Pasquotank River is a very beautiful and important body of water for the area. It has a rich history, and in earlier times provided the basis for Elizabeth City and surrounding communities. Today it is important to the area for many reasons, including the recreational activities which bring tourists to the region. Protecting this wonderful natural resource must become a priority in this region. The Environmental Science Laboratory at ECSU pledges to continue monitoring, researching and investigating water quality.