Season matters when sampling streams for swine CAFO waste pollution impacts.

Concentrated (or confined) animal feed operations (CAFOs) are the principal means of livestock production in the United States, and such facilities pollute nearby waterways because of their waste management practices; CAFO waste is pumped from the confinement structure into a cesspit and sprayed on a field. Stocking Head Creek is located in eastern North Carolina, a state with >9,000,000 head of swine confined in CAFOs. This watershed contains 40 swine CAFOs; stream water quality was investigated at seven sites during 2016, with five sampling dates in early spring and five in summer. Geometric mean fecal coliform counts were in the thousands/100 mL at five sites in spring and all seven sites in summer. Excessive nitrate pollution was widespread with concentrations up to >11.0 mg N/L. Seasonality played an important role in pollutant concentrations. In North Carolina, spraying animal waste on adjoining fields is permissible from March 1 through September 30. Seasonal data showed significantly higher (p < 0.01) concentrations of conductivity, nitrate, total nitrogen, total organic carbon, and fecal bacteria in summer as opposed to early spring. Thus, sampling performed only in winter-early spring would significantly underestimate impacts from swine CAFO spray fields on nearby waterways.

Microcystins and two new micropeptin cyanopeptides produced by unprecedented Microcystis aeruginosa blooms in North Carolina's Cape Fear River.

The Cape Fear River is the largest river system in North Carolina. It is heavily used as a source of drinking water for humans and livestock as well as a source of irrigation water for crops, and production water for industry. It also serves as a major fishery for both commercial and recreational use. In recent years, possibly related to increased eutrophication of the river, massive blooms of cyanobacteria, identified as Microcystis aeruginosa have been observed. Bloom samples collected in 2009 and 2012 were chemically analyzed to determine if they contained cyanobacterial toxins known as microcystins. Both blooms were found to produce microcystins in high yields. Microcystins are potent hepatotoxins that can be bio-accumulated in the food chain. Recent biological studies have also shown a host of other potentially harmful effects of low level microcystin exposure. Detailed chemical analysis of these blooms led us to discover that these blooms produce an additional family of cyanobacterial peptides know as the micropeptins, including two new members named micropeptins 1106 and 1120. The biological activities of these new molecules have not yet been determined, although protease activity has been well documented for this peptide group. These data indicate a need for thorough monitoring of toxin levels especially during bloom events in addition to additional biological testing of other cyanopeptides present in blooms.

High pollutant removal efficacy of a large constructed wetland leads to receiving stream improvements.

Hewletts Creek, in Wilmington, North Carolina, drains a large suburban watershed and as such is affected by high fecal bacteria loads and periodic algal blooms from nutrient loading. During 2007, a 3.1-ha wetland was constructed to treat stormwater runoff from a 238-ha watershed within the Hewletts Creek drainage. A rain event sampling program was performed in 2009-2010 to evaluate the efficacy of the wetland in reducing pollutant loads from the stormwater runoff passing through the wetland. During the eight storms sampled, the wetland greatly moderated the hydrograph and retained and/or removed 50 to 75% of the inflowing stormwater volume. High removal rates of fecal coliform bacteria were achieved, with an average load reduction of 99% and overall concentration reduction of >90%. Particularly high (>90%) reductions of ammonium and orthophosphate loads also occurred, and lesser but still substantial reductions of total phosphorus (89%) and total suspended solids loads (88%) were achieved. Removal of nitrate was seasonally dependent, with lower removal occurring in cold weather and a high percentage (90%+) of nitrate load removal occurring in the growing season when water temperature exceeded 15°C. Long-term before-and-after sampling in downstream Hewletts Creek proper showed that, after wetland construction, statistically significant average decreases of 43% for nitrate, 72% for ammonium, and 59% for fecal coliform bacteria were realized. Wetland features contributing to the high pollutant control efficacy included available space for a large wetland, construction of deep forebays, and a dense and diverse aquatic and shoreline plant assemblage.

Pollutant impacts to Cape Hatteras National Seashore from urban runoff and septic leachate.

The sandy barrier islands of Cape Hatteras National Seashore, USA, attract large seasonal influxes of tourists, and are host to numerous motels, rentals and second homes. To investigate the impacts of nearby urbanization on public trust waters, sampling was conducted in nine brackish water bodies within this coastal national park. A large tidal urban ditch delivered runoff-driven fecal-contaminated water directly into public beach waters. At all sites except the control, ammonium, phosphorus and fecal bacteria concentrations were high, strongly seasonal and significantly correlated with community water usage, indicating that increased septic tank usage led to increased pollutant concentrations in area waterways. Nutrients from septic systems caused ecosystem-level problems from algal blooms, BOD, and hypoxia while fecal microbes created potential human health problems. Septic system usage is widespread in sensitive coastal areas with high water tables and sandy soils and alternatives to standard septic systems must be required to protect human health and the environment.

Elevated levels of metals and organic pollutants in fish and clams in the Cape Fear River watershed.

A study was performed in 2003 to 2004 to assess metal and organic contaminant concentrations at three areas in the lower Cape Fear River system, North Carolina, United States. Sites examined were Livingston Creek along the mainstem of the Cape Fear River near Riegelwood, Six Runs Creek in the Black River Basin, and Rockfish Creek in the Northeast Cape Fear River basin. The results of the investigation showed that levels of metals and organic pollutants in the sediments were lower than limits considered harmful to aquatic life. However, results of fish (adult bowfin) tissue analyses showed that concentrations of arsenic (As), cadmium (Cd), mercury (Hg), selenium (Se), and now-banned polychlorinated biphenyls (PCBs), and the pesticide dieldrin were higher than levels considered safe for human consumption by the United States Environmental Protection Agency and the North Carolina Health Director's Office. Fish tissue concentrations of Hg, Se, and PCBs were also higher than concentrations determined by researchers to be detrimental either to the health of the fish themselves or their avian and mammalian predators. Due to the rural nature of two of the sites, increased concentrations of As, Cd, Se, and PCBs in fish tissue were unexpected. The likely reason the levels are increased in fish and some clams but not in sediments is that these pollutants are biomagnified in the food chain. These pollutants will also biomagnify in humans. In these rural areas there is subsistence fishing by low-income families; thus, increased fish tissue metals and toxicant concentrations may present a direct threat to human health.

Impacts of a raw sewage spill on water and sediment quality in an urbanized estuary.

A sewer main serving a large municipal wastewater system ruptured, discharging approximately 3,000,000 gallons (11,355,000 L) of raw human sewage into a multi-branched tidal creek estuary along the US East Coast. The biochemical oxygen demand caused severe hypoxia in the system, causing a large fish kill. The sewage load led to high fecal coliform bacteria concentrations in the creek (maximum of 270,000 CFU 100ml(-1)), which declined in an approximate logarithmic manner over the first few days. The spill caused elevated sediment fecal coliform bacteria and enterococcus counts that declined much more gradually than water column counts. Persistence of relatively high concentrations of fecal indicator bacteria in sediments for several weeks after the spill suggests that sediment sampling should be included in response to major sewage spills. The high concentration of nutrients in the spilled sewage led to several algal blooms. However, nutrient concentrations in the water column declined rapidly, demonstrating the value of conserving marshes because of their pollutant filtration function.