POLLUTANT CHARACTERIZATION OF SEDIMENTS IN THE NEW RIVER ESTUARY AS RELATED TO WATERSHED ACTIVITIES

The accumulation of pollutants in stream and estuarine sediments and the subsequent effects on the aquatic ecosystem have long been an area of concern for researchers, resource and regulatory agencies, the regulated community and the public. Despite these concerns, there is little baseline pollutant characterization data of sediments to evaluate potential impacts. The Marine Corp Base (MCB), Camp Lejuene is located along the New River estuary in Onslow County, North Carolina and has recently constructed an advanced wastewater treatment facility (AWRF) that discharges through a diffuser into the New River. In permitting the new facility and discharge location, agencies within the North Carolina Department of Environment and Natural Resources (DENR) requested Camp Lejeune to conduct sediment and water quality monitoring to characterize conditions prior to initiation of discharge. Sediments in the estuary are affected from a number of sources including upstream agricultural and urban development within the New River watershed as well as the urban and “industrial” impacts from the MCB.In response to the DENR requirements, Camp Lejeune developed a sampling program that included:A far-field sediment and water quality monitoring study that establishes baseline sediment and water quality conditions for various segments of the New River to define effects from different portions of the watershed;A near-field sediment monitoring plan that determines whether pollutants accumulate in the sediments in the vicinity of the outfall, by conducting sampling before and after the discharging begins.Sediments were characterized along three transects as part of the near-field samples and ten transects for the far field samples. The initial characterization of sediments and water quality was conducted in June and early July 1998. The near-field characterization was repeated in June 1999. Pollutant parameters were as follows: SedimentPhysical/Bioavailability: Grain Size, Total Organic Carbon, Acid Volatile SulfidesMetals: Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Selenium, Silver, and ZincPolycyclic Aromatic Hydrocarbons (PAHs): Acenaphthene, Anthracene, Benzo [a] anthracene, Benzo [a] pyrene, Chrysene, Fluoranthene, Fluorene, Naphthalene, Phenanthrene, Pyrene, and Total Polycyclic Aromatic HydrocarbonsChlorinated Hydrocarbons: PCB Arochlors, Total PCB's DDT, DDE, DDD, Total DDT, Dieldrin, Endrin, Chlordane, Hexachlorobenzene, Lindane, and Toxaphene.Surface WaterPhysical: Dissolved oxygen (DO) (corrected for salinity), Salinity, Temperature, Conductivity, pH, and Secchi DepthChemical: Total Phosphorus, TKN, Ammonia, Nitrite/Nitrate, Chlorophyll a, and Fecal Coliforms.Results of the initial sampling showed few detectable levels of hydrocarbons. Metals results were generally low and showed a decreasing trend from the upstream transects in Wilson Bay (near the City of Jacksonville, NC) to the downstream area. Near-field results showed no significant differences after one year of discharge through the diffuser to the New River from AWRF. Results were compared to National Oceanic and Atmospheric Administration (NOAA) criteria for sediments and all results were below these criteria except for transect samples in the upper estuary near Wilson Bay and tributaries.In addition to meeting DENR requirements, the characterization effort has been used as information for local stakeholder groups in evaluating water quality and sediment problem areas within the New River. The information collected generally indicates that the New River estuary problems associated with contaminated sediments are limited spatially and are not as severe as “alleged” by various interest groups.