Environmental and Health Issues With Anaerobic Manure Lagoons


Toxic Fumes

The decomposition of manure in lagoons by anaerobic bacteria produces toxic airborne compounds, which can be harmful to human health and the environment.

A study performed in North Carolina showed people living nearby a 6,000-head intensive pig farm reported increased rates of headaches, runny nose, sore throat, excessive coughing, diarrhea and burning eyes compared to rural residents living far from livestock operations. Additionally, rates of asthma in children living near intensive farms are consistently elevated.

The process of anaerobic digestion has been shown to release over 400 volatile compounds from lagoons. The most prevalent of these are: ammonia, hydrogen sulfide, methane, and carbon dioxide.


In the United States, 80 percent of ammonia emissions come from livestock production. The urea (a component of urine) stored in the lagoon contains ammonium, which is a liquid nitrogen compound.

Through ammonia volatilization, a lagoon can vaporize up to 80 percent of its nitrogen through the reaction: NH4+-N -> NH3 + H+. As pH or temperature increases, so does the amount of volatilized ammonia. Once ammonia has been volatilized, it can travel as far as 300 miles, and at closer ranges it is a respiratory irritant.

Acidification and eutrophication of the ecosystem surrounding the lagoons could be caused by prolonged exposure to volatilized ammonia. This volatilized ammonia has been implicated in widespread ecological damage in Europe, and is becoming a growing concern for the United States.

Hydrogen Sulfide

Lagoons have high concentration of the toxic gas hydrogen sulfide. A study by the Minnesota Pollution Control Agency has found that concentrations of Hydrogen sulfide near lagoons have exceeded the state standard, even as far away as 4.9 miles.

Hydrogen sulfide is recognizable for its unpleasant rotten-egg odor. Exposure to the gas can cause eye, nose and throat irritation, diarrhea, hoarseness, sore throat, cough, chest tightness, nasal congestion, heart palpitations, shortness of breath, stress, mood alterations, sudden fatigue, headaches, nausea, sudden loss of consciousness, comas, seizures and death. Because hydrogen sulfide is heavier than air, it tends to linger around lagoons even after ventilation. Levels of hydrogen sulfide are at their highest after agitation and during manure removal.


Methane is an odorless, tasteless, colorless gas, which is fatal at high levels (though these levels are not usually seen at lagoons). Lagoons produce about 2,300,000 metric tons per year, with around 40 percent of this number coming from swine lagoons. Methane is combustible at high temperatures and explosions and fires are a real threat at, or near, lagoons. Additionally, methane is a potent greenhouse

gas. The EPA has estimated that 13 percent of all the methane emissions came from livestock manure in 1998, and this number has grown in recent years.

Carbon Dioxide

Carbon Dioxide is a main product of anaerobic respiration within the lagoon. Though it is not toxic in itself, health effects include: respiratory problems, eye irritation and headaches. Carbon dioxide is also considered a greenhouse gas.

TM Water Soluble Contaminants

Contaminants that are water soluble can escape from anaerobic lagoons and enter the environment through leakage from badly constructed or poorly maintained manure lagoons as well as during excess rain or high winds, resulting in an overflow of lagoons. These leaks and overflows can contaminate surrounding surface and ground water with some hazardous materials which are contained in the lagoon. By definition spreading slurry on land spreads those contaminants. The most serious of these contaminants are pathogens, antibiotics, heavy metals and hormones.


There are more than 150 pathogens in manure lagoons that have been found to impact human health. Healthy individuals who come into contact with pathogens usually recover promptly.

However, those who have a weakened immune system, such as cancer patients and young children,have an increased risk for a more severe illness or even death. About 20 percent of the U.S. population is categorized in this risk group.

Some of the more notable pathogens are:

E. Coli

E. Coli is found in the intestines and feces of both animal and humans and is extremely virulent. One particular strain Escherichia coli O157:H7 is found specifically in the lumen of cattle raised in CAFOs.

Because cattle are fed corn in CAFOs instead of grass, this changes the pH of the lumen so that it is more hospitable to E. Coli. Grain-fed cattle have 80 percent more of this strain of E. Coli than grassfed cattle.


Cryptosporidium is a parasite that causes diarrhea, vomiting, stomach cramps and fever. It is particularly problematic because it is resistant to most lagoon treatment regimens. In a tudy performed in Canada, 37 percent of swine liquid-manure samples contained Cryptosporidium.

Some other common pathogens (and their symptoms)

  • Bacillus anthracis, otherwise known as Anthrax (skin sores, headache, fever, chills, nausea, vomiting)
  • Leptospira pomona (abdominal pain, muscle pain, vomiting, fever)
  • Listeria monocytogenes (fever, fatigue, nausea, vomiting, diarrhea)
  • Salmonella (abdominal pain, diarrhea, nausea, chills, fever, headache)
  • Clostirdum tetani (violent muscle spasms, lockjaw, difficulty breathing)
  • Histoplasma capsulatum (fever, chills, muscle ache, cough rash, joint pain and stiffness)
  • Microsporum and Trichophyton Ringworm (itching, rash)
  • Giardia lamblia (abdominal pain, abdominal gas, nausea, vomiting, fever)
  • Cryptosporidium (diarrhea, dehydration, weakness, abdominal cramping)
  • Pfiesteria piscicida (neurological damage)

The full presentation can be seen HERE

Remember this presentation (which was published in 2012) is by a vendor of agricultural equipment to farmers. It is simply stating facts that are recognised to be true by the agricultural industry.

How on earth can we allow the unregulated storing and spreading of hundreds of millions of gallons of slurry across the UK?

2 thoughts on “Environmental and Health Issues With Anaerobic Manure Lagoons”

  1. Would be interesting, if it is possible to source the info from Public Health, how many of the listed illnesses have occurred near large scale dairy units. It may be time someone did the research. I have a personal interest as I had e coli eighteen months ago and the source was unknown as I am vegetarian and don’t eat take away food. The official who spoke to me thought the most likely source was cattle. I live in Welcombe.

    • Ruth,
      I apologise for the delay in getting back to you. (A newsletter coming out shortly will explain.) We are back on the campaign trail and the revised home page of the website explains what we are hoping to do.
      Your reference to your e coli infection is very interesting. May I ask to you provide more detail in letter form (which you can send by email but we need your name and address on the document) including the name of the official and his or her title.
      That would be most helpful.

      Many thanks.
      Jeremy (Roe)


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