Chronic Stream Pollution in a CAFO Rich Watershed in Duplin County, NC Michael A. Mallin, Matthew R. McIver, Amanda Kahn Dickens and Anna R. Robuck Center for Marine Sciences University of North Carolina Wilmington mallinm@uncw.edu
Stocking Head Creek Stream originates in swine waste sprayfield Swine and poultry CAFOs mixed in watershed No point sources, only 67 human dwellings in watershed Swine CAFO Poultry CAFO Tributary stream site TR SDCR Largely sandy stream sediments at sampling stations
There are many head of cattle in the watershed (unquantified), many who graze directly under swine waste spray
Field and Laboratory Methods Surface water samples were collected at 7 stream stations on 5 sampling runs within a 30 day period in both summer (July August 2013) and fall (September October 2013) Sampling was performed using procedures required by NCDENR for assessment of use support of NC waters for fecal coliform concentrations. Sampling was performed in both rain and non rain conditions, with statistical analysis (after log transformation) to determine if significant pollution was due to acute surface stormwater runoff, or chronic pollution. Nutrients, TOC, BOD5 and fecal coliform analysis were performed at a state certified contract lab and field parameters and chlorophyll a were performed at the UNCW CMS Aquatic Ecology Laboratory, which is state certified for those parameters. UNCW follows QA/QC procedures of the Lower Cape Fear River Program and is audited annually by NCDENR.
GIS based methods The ArcMap 10.1 Hydrology toolset was utilized, and the catchment area of Stocking Head Creek system was identified. A shapefile including all of the documented animal operations from the NC OneMap geospatial portal was clipped to only display those CAFOs within the newly defined watershed area (these consist of swine CAFOs). 2012 orthophotography from the North Carolina OneMap service was analyzed for undocumented CAFOs. The signature shape of the farm buildings (long rectangles side by side) was used to identify these locations, which were presumed to be poultry CAFOs. These were manually digitized as polygons superimposed on the aerial photos, and added to the existing CAFO location data to provide a more accurate assessment of the total number of animal operations within the Stocking Head Creek watershed. The dimensions of each poultry building were computed from the digitized aerial photographs. Maximum bird (considered as broiler chickens) population per building were estimated by assuming 743 cm 2 (0.80 ft 2 ) of space allotted per bird as is standard for a major poultry producer (Sanderson Farms 2007). The United Egg Producers (2010) recommend 436 557 cm 2 (0.47 to 0.60 ft 2 ) of space per egg laying chicken; thus, we feel our counts are conservative. As there is no way to distinguish chicken from turkey operations from the air, for the purposes of this study we assumed all broiler chickens.
Stocking Head Creek, Duplin County, North Carolina. Catchment area is 4,893 acres (1,980 ha) and stream length to the Northeast Cape Fear River is 13.7 mi (22.1 km). Contains 40 swine CAFOs permitted for 94,068 head of swine. Poultry estimated (by UNCW) as broilers or other chickens approximately 1.3 million birds in SHC watershed.
Ammonium Concentrations In Stocking Head Creek 2013, mean + standard error 14.0 12.0 10.0 mg g N/L 8.0 6.0 4.0 2.0 0.0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Station Ammonium concentrations were highest at sites abutting swine waste sprayfields, stations TR SDCR and SHC SHCR. The maximum ammonium concentration found was 38.7 mg N/L at TR SDCR on September 16, 2013.
The most NH 4+ impacted sites were those adjacent to swine waste sprayfields, for example the Stocking Head Road ste(abo site (above left et and right). An aerial photograph of the watershed shows sprayfield drainage running into creekside wetlands immediately adjacent to the sprayfield.
Nitrate concentrations in Stocking Head Creek, 2013, mean + standard error 10.0 9.0 8.0 7.0 mg g N/L 6.0 5.0 4.0 3.0 2.0 1.0 0.0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Stationti In ten of the 70 samples nitrate N concentrations exceeding 10 mg/l (an EPA criteria to prevent blue baby syndrome) were found in creek samples. Peak areas were not adjacent to spray fields, demonstrating considerable sub surface nitrate movement towards the stream.
Total N concentrations in Stocking Head Creek, 2013, as median 10.00 9.0 8.0 7.0 mg N/L 6.0 5.0 4.0 3.0 2.0 1.0 0.0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Station For perspective, using a large data set of 1,070 streams Dodds et al. (1998) determined that TN concentrations > 1.5 mg/l were characteristic of eutrophic conditions. Dodds, W.K., J.R. Jones and E.B. Welch. 1998. Suggested classification of stream trophic state: distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Research 32:1455 1462.
Total P concentrations for Stocking Head Creek, 2013, as median 1.8 1.6 14 1.4 1.2 mg g P/L 1.0 0.8 0.6 0.4 0.2 0.0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Station For perspective, using data from 1,366 streams, Dodds et al. (1998) concluded that TP concentrations > 0.075 mg/l were characteristic of eutrophic streams. Dodds, W.K., J.R. Jones and E.B. Welch. 1998. Suggested classification of stream trophic state: distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Research 32:1455 1462.
BOD5 Concentrations for Stocking Head Creek, 2013, as mean + standard error 30.0 25.0 20.0 mg g/l 15.0 10.0 5.0 0.0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Station BOD5 exceeded 10 mg/l on 11 of 70 samples in this creek; maximum of 88 mg/l at TR SDCR. From a wide variety of Coastal Plain Streams Mallin et al. (2006) determined that BOD5 of 1 to 2 mg/l could be considered the normal range. Mallin, M.A., V.L. Johnson, S.H. Ensign and T.A. MacPherson. 2006. Factors contributing to hypoxia in rivers, lakes and streams. Limnology and Oceanography 51:690 701.
What drives biochemical oxygen demand (BOD) in Stocking Head Creek? We performed correlation analyses between BOD and several water quality parameters Correlation results BOD vs TOC: r = 0.833, p < 0.0001 BOD vs ammonium: r = 0.666, p < 0.0001 BOD vs TP: r = 0.626, p < 0.0001 BOD vs orthophosphate: r = 0.569, p < 0.0001 BOD vs chlorophyll a: r = 0.316, p = 0.008 BOD vs TN: r = 0.284, p = 0.017 Best predictive linear regression model dlfor BOD in SHC: BOD5 = 0.952(TOC) + 0.367(ammonium) 3.961 R 2 = 0.85, p < 0.0001
Algal blooms occurred at times at the sampling sites, but were g p g, inconsistent in space and time. On several occasions high chlorophyll a levels coincided with high BOD5 concentrations.
4,500 4,000 Fecal coliform counts for Stocking Head Creek summer 2013 geometric mean of 5 samples in 30 days fecal coliform ms CFU/100 ml 3,500 3,000 2,500 2,000 1,500 1,000 500 0 TR SDCR SHC GDR SHC CSR CSR SHC SDCR SDCR SHC SHCR SHCR SHC 50 SHC PBR Stations Upper 5 stations exceed 400 CFU/100 ml 100% of the time sampled All7 stations exceeded 200 CFU/100 ml 100% of occasions sampled
Fecal coliform counts for Stocking Head Creek fall 2013 geometric mean 5 samples in 30 days 10,000 9,000 fecal coliform ms CFU/100 ml 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 0 TR SDCR SHC GDR SHC CSR SHC SDCR SHC SHCR SHC 50 SHC PBR Stations The off screen geometric mean at station TR SDCR is 32,700 CFU/100 ml. U 4 f 5 t ti d 400 CFU/100 l 100% f th ti l d Upper 4 of 5 stations exceed 400 CFU/100 ml 100% of the time sampled All 7 stations exceeded 200 CFU/100 ml 100% of occasions sampled
Median pollutant concentrations in Stocking Head Creek in rain vs non rain periods. T test ss indicated no significant difference between periods. This indicates that that the upper groundwater table contains elevated fecal bacteria and inorganic nitrogen CFU U/100 ml 1,400 1,200 1,000 800 600 400 Fecal coliform counts (as median) for rain vs non rain periods in Stocking Head Creek 200 0 Rain Non rain Ammonium concentrations (mg/l) for rain vs non rain periods in Stocking Head Creek 8.0 Nitrate concentrations (mg/l) for rain vs nonrain periods for Stocking Head Creek 10.0 Am mmonium (mg N/) 6.0 4.0 2.0 Nitrat (mg N/ /L) 8.0 6.0 4.0 2.0 0.0 Rain Non rain 0.0 Rain Non rain
Summary human health and ecological issues The North thcarolina protocol states tt that t fecal coliform counts shall not exceed a geometric mean of 200 CFU/100 ml based on at least five consecutive samples during any 30 day period, nor exceed 400 CFU/100 ml in more than 20% of the samples examined during such period. Stocking Head Creek fits all criteria for non support of designated use due to excessive fecal coliform pollution, and should be candidate for inclusion onthe 303(d) list. This creek also has some of highest ammonium and nitrate concentrations our laboratory has found in eastern NC: on par with levels l seen in CAFO spills and failing WWT plants Stream BOD concentrations were correlated with TOC, ammonium, phosphorus and algal blooms. This stream drains into the Northeast Cape Fear River, which enters the Cape Fear River at Wilmington. The lower CFR andestuaryare are on the NC 303(d) list for low dissolved oxygen and is required to produce a TMDL although reclassification actions are currently ongoing.
Other thoughts Pollution in this stream is chronic, meaning that it is not necessarily driven by stormwater pulses but has constant inputsof ammonium, nitrate andfecal bacteria entrained in groundwater through sprayfield contributions. Excessive land use of industrial scale swine (as much as 94,000 head), poultry (over 1.3 million chickens or equivalent wt. of turkeys, or some combination) are polluting this stream with ihfecal lbacteria, nutrients, and BOD. Action should be taken to require industry to address this non point source pollution to bring this (and other similar) streams into compliance with North Carolina standards. The present proposal p to reclassify the lower CFR basin to swamp water status does not address these sources of BOD and nutrients
New poultry houses, Duplin Co., NC 2013 Turkeys in NC poultry house, 2013 A i l i f D li C NC 2013 Aerial view of Duplin Co., NC 2013, patchwork of swine and poultry CAFOs, + cattle grazing