Literature Review on Hog Lagoons

The literature we examined evaluates North Carolina’s $2.9 billion hog industry, which is the second largest in the United States (McGrath 2005). Duplin County, North Carolina has the highest hog concentrations in the country with a hog population of 2.2 million (Kilborn 1999). Each year, Duplin County hogs produce 15.5 million tons of waste that are not adequately handled (Nicole 2013). Despite the hog industry’s economic prosperity, human health and water integrity suffer from poor hog waste infrastructure and extreme weather events, which increase toxic runoff. In this paper, we will examine literature about hog waste in North Carolina and its relationship with extreme weather, environmental injustice and current waste management technologies.

In eastern North Carolina, where the hog farms are concentrated, the water table often sits less than five feet from the surface (Eimers et al. 2001). This makes the area susceptible to flooding, especially during hurricanes and other extreme weather events (Stevens 1999). In 1998, Hurricanes Dennis and Floyd dumped tremendous amounts of rain onto the eastern North Carolina terrain in a two-week time frame, which led to many flooded hog lagoons (Stevens 1999). With current practices, hog waste sits in above ground lagoons, only being held in place by dikes that often break during above average rainfall (Schmidt 2000.) Hog waste bacteria, ammonia, and nitrates added to the watershed during floods act as catalysts for phytoplankton and algae blooms that create hypoxic dead zones (Burkholder et al. 1997). Current hog farming practices do not include precautionary steps to prevent downstream ecological damage.

Floods from Hurricane Floyd led to thousands of dead hogs decomposing in standing water, which contaminated groundwater with pathogenic bacteria (Bullard 2008). Monitoring wells are rarely present to test for groundwater pollution after lagoons overflow, leaving residents to unknowingly use and drink contaminated water (Mallin et al. 2015). Testing of surrounding water sources and groundwater showed contamination with parasites, viruses, hormones, pharmaceuticals, and antibiotic-resistant bacteria from hog waste (Peach 2014). These long-standing vulnerabilities were highlighted when 14 hog lagoons overflowed during rainfall from Hurricane Matthew in 2016 (Board 2016). The percentage of rainfalls characterized as “extreme” events has increased from 5% in 1970 to 48% in 2010, which highlights the increasing need to address flooding concerns (Irfan 2017). The literature we reviewed prompts concern that increasing flooding instances amplifies the ability of the hog industry to affect the water security of their communities, downstream sources, and water dependent industries like fishing.

Environmental injustice in eastern North Carolina results from failures to fairly and effectively handle hog waste. Hog waste sits without treatment in lagoons until sprayed onto land and crops as fertilizer (Nicole 2013). The spray fertilizers make the waste airborne and wind dispersible (Mallin et al. 2015). Therefore, adjacent communities are exposed to the hog waste polluted air and contaminated groundwater (Nicole 2013). Waste compound exposure and ingestion cause inflammatory, immunological, psychological, and neurological disease among residents (Wing and Wolf 2000). The spraying causes community-wide stench and toxin exposure symptoms like wheezing and high blood pressure (Wing and Wolf 2000). Minority and impoverished communities are affected by the pollution, highlighting the environmental injustice and discriminatory effects of the hog waste industry (Wing et al. 2000). Consensus among researchers at North Carolina universities exists regarding the toxic effects of compounds found in hog waste on human and water system health.

North Carolina has the least strict guidelines in the United States for hog farms and lack of enforcement for existing policies (Skolnick 2016). Despite devastation from the 1998 hurricane season, 4,000 lagoons from prior to 1997 are still in use (Board 2016).  Any attempt to change the regulations generates pushback from the North Carolina Pork Council, a hog industry lobbying group (Kilborn 1999). The selected literature does not evaluate economic policies such as subsidies and grants to help offset the cost of adopting of new technologies A gap in the literature exists when examining the effectiveness of the regulation of 40% of US lagoons by the EPA under the Clean Water Act  (Peach 2014). Subjecting waste lagoons to municipal treatment plants has been proposed along with anaerobic bacteria digester systems (Peach 2014). While some literature suggests these alternatives are effective at limiting stench, controlling runoff, and treating toxic waste compounds, other literature sources we reviewed claim these alternatives are not economically sustainable (Peach 2014). However, the existing literature on hog management practices covers new technological innovations and alternatives to the lagoon spray field system but exclude new cost-effective systems from serious consideration.

The literature demonstrated that extreme precipitation events caused hog lagoon overflows, which resulted in severe human health and ecological damages. We examined current regulations and determined that they do not protect the watershed or surrounding communities, which are disproportionately affected by the air and water contamination from hog farms. The literature we examined suggested a lack of economically and technologically viable alternatives to North Carolina’s current hog lagoon system. Despite consensus among all reviewed sources that current waste management practices are not sustainable, alternatives continue to be debated over economic and political feasibility. From this, we determined that offsetting costs of implementation of new technology will be the most critical factor in reforming industrial hog farming waste management practices.


Works Cited

Board, The Editorial. 2016. “North Carolina’s Noxious Pig Farms.” The New York Times. (March 1, 2018).

Bullard, Robert D. 2008. “Differential Vulnerabilities: Environmental and Economic Inequality and Government Response to Unnatural Disasters.” Social Research; New York [BG1] 75(3): 753–784,1033.

Burkholder, JoAnn M., Michael A. Mallin, Matthew R. McIver, et al. 1997. “Comparative Effects of Poultry and Swine Waste Lagoon Spills on the Quality of Receiving Streamwaters.” Journal of Environmental Quality 26(6): 1622.

Burkholder, JoAnn M., Michael A. Mallin, Howard B. Glasgow, et al. 1997. “Impacts to a Coastal River and Estuary from Rupture of a Large Swine Waste Holding Lagoon.” Journal of Environmental Quality; Madison 26(6): 1451.

Hellerstein, Erica, and Ken Fine. 2017. “A Million Tons of Feces and an Unbearable Stench: Life near Industrial Pig Farms.” The Guardian. (March 1, 2018).

Irfan, Umair. 2017. “One of the Clearest Signs of Climate Change in Hurricane Maria, Irma, and Harvey was the Rain.” Vox. (March 1, 2018).

Kilborn, Peter T. 1999. “Hurricane Reveals Flaws in Farm Law as Animal Waste Threatens N. Carolina Water.” The New York Times. (March 1, 2018).

Mallin, Michael A., Matthew R. Mciver, Anna R. Robuck, and Amanda Kahn Dickens. 2015. “Industrial Swine and Poultry Production Causes Chronic Nutrient and Fecal Microbial Stream Pollution.” Water, Air and Soil Pollution; Dordrecht 226(12): 1–13.

McGrath, Gareth. 2005. “Smells like a Winner ; But Could New Technology Replace Hog Lagoons, Fields?; System Separates Waste, Produces Potable Water Quickly.” Star – News; Wilmington, N.C.: 1.A.

Peach, Sara. 2014. “What to do About Pig Poop? North Carolina Fights a Rising Tide.” National Geographic News. (March 1, 2018).

Skolnick, Adam. 2016. “More than a Dozen Breached Hog Waste Lagoons Found in North Carolina After Hurricane Matthew.” Sierra Club. (March 1, 2018).

Nicole, Wendee. 2013. “CAFOs and Environmental Justice: The Case of North Carolina.” Environmental Health Perspectives (Online); Research Triangle Park 121(6): A182

Schmidt, Charles W. 2000. “Lessons from the Flood: Will Floyd Change Livestock Farming?” Environmental Health Perspectives 108(2): A74.

Stevens, William K. 1999. “After the Storm, an Ecological Bomb.” The New York Times. (March 1, 2018).

Eimers, Jo Leslie, Sara Terziotti, and Mary Giorgino. 2001.  “Estimated Depth to Water, North Carolina.” (March 1, 2018).

Wing, Steve, Dana Cole, and Gary Grant. 2000. “Environmental Injustice in North Carolina’s Hog Industry.” Environmental Health Perspectives 108(3): 225-31, (March 1, 2018).

Wing, Steve, and Susanne Wolf. 2000. “Intensive Livestock Operations, Health, and Quality of Life among Eastern North Carolina Residents.” Environmental Health Perspectives 108(3): 233-38, (March 1, 2018).

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