As we celebrate World Farm Animals Day, we contemplate how we as a society can find ways to treat our livestock in a more humane way or, better yet, look for ways to eliminate them in our diet. Aside from this, we should also think about how livestock farm operations are ruining our environment by contributing to ammonia water pollution.
What is ammonia?
The chemical formula for ammonia is NH3. Natural ammonia is important to the environment as they are involved in the nitrogen fixation, mineralization, and nitrification process.6
What is ammonia used for?
In the agriculture industry, ammonia is used in fertilizer and animal feed production. Furthermore, it is needed in the production of fibres, plastics, paper and rubber.6
Should we be concerned when there is ammonia in water?
As explained later in this post, drinking water that contains ammonia does not cause ammonia poisoning. However, high levels of ammonia in water should still be a cause of concern.
Ammonia and Livestock waste
Animal waste and human waste are considered to be the natural sources of ammonia in water. In fact, half of the manure’s nitrogen is in the form of ammonia. This ammonia can be lost through volatilization when the environment is warm and windy and can contribute to ammonia pollution of the air. The volatilization of ammonia can occur during the collection, storage, and land disposal of the manure. This gaseous ammonia could then contribute to water acidification, ammonia in water, and water pollution by nitrates.2,3,4
In pasture fields, the vegetation present is often low lying and does not provide an effective canopy over the soil that they are susceptible to agricultural runoff. Rain may help manure penetrate the soil. However, too much soil moisture may also make the soil susceptible to run-off. Besides ammonia, agricultural runoff may also carry other nutrients like nitrogen and phosphorus which may lead to harmful algal blooms. Runoff may also erode soil particles that contain ammonia, nitrogen, and phosphorus which are then deposited as sediment in bodies of water. These deposited sediments may cause delayed algal blooms.1,2
Effects of Agricultural Runoff and High levels of Ammonia in Water
Agricultural Runoff, which carries ammonia, nitrogen, phosphorus, and other nutrients present in livestock manure, leads to several disastrous consequences like algal blooms, dead zones, ammonia poisoning, and nitrate poisoning in aquatic ecosystems.
Some microorganisms can break down the ammonia in water into nitrogen. This nitrogen would then be taken up by aquatic plants and algae. The aquatic ecosystem is highly dependent on these aquatic plants and algae. However, in cases where there are excess nutrients in the environment, they would grow out of control. You may ask, “wouldn’t it be great to have a lot of photosynthetic aquatic plants and algae to provide oxygen to the aquatic environment?” At first, it is, but when the excess nutrients would be used up and they would start to die off in large numbers, they would suck away the dissolved oxygen in the water and create ‘dead zones’.2
There are numerous factors that could contribute to the depletion of dissolved oxygen in an aquatic environment, one of them is algal blooms. At the end of the bloom when the algae would die in huge quantities, the decomposition process would suck out most of the dissolved oxygen in the water. This aquatic area that is devoid of oxygen is referred to as ‘dead zones’. Any living organism that is dependent on oxygen for survival will suffocate and die in these dead zones. Some cases of Fish-kills, or the sudden death of a huge number of fishes, are caused by the appearance of these dead zones.2
Ammonia can cause direct toxic effects on aquatic life. In controlled laboratory tests, ammonia concentrations of 0.3 to 0.9 mg/L were enough to kill half of the population of their coldwater fish test animal. For warm water fishes, ammonia concentrations of 0.7 to 3.0 mg/L exhibited the same results. Finally, for marine fishes ammonia concentration of 0.6 to 1.7 mg/L also resulted in the death of half of the test animal’s population. The effects of these ammonia concentrations in actual aquatic environments were more or less harmless due to the fact that other factors such as pH and temperature came into play. Nevertheless, extremely high levels of ammonia in bodies of water can cause ammonia poisoning to the creatures that are living in it.2,5
Manure can contain small amounts of nitrates. However, when there is a lot of manure around then the level of nitrate present in the soil would rise significantly. Nitrates are not held tightly by the soil, so when it rains they easily leach downwards and may mix with groundwater.2
Nitrate is generally non-toxic but if you consume nitrates in high enough concentrations then you might get nitrate poisoning. High levels of nitrate in the body have been attributed to methemoglobinemia and poor RBC oxygen absorption.2
Other concerns with regards to the Presence of Ammonia in Water
Although ammonia may not be toxic towards humans, it may be an indicator of another problem. High levels of ammonia may indicate faecal pollution. As mentioned previously, livestock rearing may lead to the contamination of bodies of water with faecal matter. Their faecal matter contains a lot of ammonia which increases the ammonia levels in the contaminated waters. Despite this, not all cases of high ammonia levels in bodies of water are due to faecal pollution. In other words, ammonia tests are not reliable indicators of faecal pollution. Thus, when faecal pollution is suspected more reliable methods of detecting faecal pollution such as the Multiple Fermentation Tube method is required to confirm it.6
How do you reduce ammonia in water? Methods of Preventing Ammonia Pollution
The volatilization of ammonia in animal waste may be avoided by composting them in a compost pit. This is quite easy to do and is cost-effective. To create a compost pit, basically, you just need to create a pit in the ground and throw organic materials into the pit like dried leaves, dead plants, and livestock waste. Other benefits of composting include reduction of volume and moisture of the animal waste which makes them easier to handle, sanitation, odour removal, and safe storage if the compost pit is covered with a tarp. Compost pit significantly reduces the possibility of ammonia pollution due to agricultural runoff compared to incorporating animal waste in the crop fields directly.3
The solid and liquid fractions of manure and animal wastes can be separated through a variety of means be it mechanical or chemical. In doing so, animal waste and manure may become more manageable. Various treatment strategies may now be applied to the liquid fraction and solid fraction separately. Treatment strategies may be effective for one fraction but not both. Furthermore, nutrient recovery methods which are unsuitable to raw animal waste or manure is more feasible with the use of solid-liquid separation.3
We can tackle the whole ‘ammonia from animal waste problem’ directly by eliminating the ammonia which is present in the animal waste. This can be done by utilizing several nitrification-denitrification systems. Through the nitrification-denitrification process, a significant amount of reactive nitrogen compounds, including ammonia, are converted into other less environmentally-harmful forms.3
Candidatus Brocadia caroliniensis is a bacterium strain that was discovered in the United States. This bacteria is capable of oxidizing ammonia (NH3) and releases Nitrogen gas (N2) as a byproduct. This bacteria is primarily used for treating agricultural, industrial, or municipal wastewaters which may contain high amounts of ammonia. Although its application for eliminating ammonia in animal waste and manure is still being studied, it is a promising methodology for removing and preventing ammonia in water nonetheless.3
Frequently asked questions
Is ammonia in Drinking water safe?
The question we should ask first is, “Is it possible for ammonia to be present in drinking water?” The answer is yes. Whether the drinking water is taken from groundwater or surface water sources there will always be some level of ammonia present in them. For groundwater, the natural level of ammonia is 0.2 mg per litre; some may even reach 3 mg per litre. For surface waters, the natural level of ammonia is 12 mg per litre. Furthermore, the ammonia in water may come from disinfection procedures which utilizes chloramines.6
The pipes that bring the water to the consumers may also introduce ammonia into the drinking water. Some pipes are coated with cement mortar which may introduce significant amounts of ammonia into the drinking water.6
There are currently no research papers that provide quantitative data regarding the human body’s capacity to metabolize ammonia. In animal studies, the ammonia ingested were converted to glutamate and urea within 30 minutes. The urea is then metabolized further in the liver into urinary urea and 25% of this urea is excreted through the urinary system as urine. The remaining 75% is completely eliminated from the animal’s body after three days. In these animal studies, researchers noted that ammonia ingestion rarely raises ammonia levels within a person’s body. Thus, ingesting ammonia in water does not pose any potential health hazard.6,8
Although ammonia ingestion through drinking water does not do you any harm, it may still compromise the quality of the drinking water in other ways. First and foremost, the ammonia may interfere with chlorine and render the disinfectant less effective. As little as 0.2 mg of ammonia per litre of drinking water may reduce chlorine concentrations by up to 68% which significantly reduces the efficacy of the disinfection procedure. The ammonia may react with the manganese-removal filters rendering them less effective. This, in turn, would increase the amount of manganese in the water and would make the water taste earthy and mouldy.6
What happens when ammonia reacts with water?
When ammonia comes into contact with water it will react with it and form ammonium hydroxide. This is a corrosive chemical that can damage our cells and tissues. This is especially true with our mucus membranes. Gaseous ammonia reacts with the water present in our mucus membrane thus irritating our mucosal lining like those found in our eyes, nose, and throat.7
Although cases are almost always intentional, ingesting ammonia at very high amounts can lead to ammonia poisoning. This can cause chemical burns on the mouth, throat, and stomach.7
World Farm Animals Day is the perfect day to contemplate about how our treatment of farm animals, especially livestock animals, affects the environment. Our aquatic ecosystems are especially vulnerable to our livestock rearing activities. Ammonia present in their waste can get carried away and deposited to various bodies of water. This may lead to further complications which can be detrimental to both humans and animals despite the fact that ammonia ingestion is rarely harmful to man.