Intensive animal agriculture creates waste materials and pollutants whose concentrations pose risks to the environment, communities and to investors in the sector. This article explores this issue, looking at risks and mitigations as well as the status of regulation around the world.
Why agricultural waste and pollution risk matters?
The number of livestock on the planet (19 billion chickens, 1.5 billion cows, 2 billion sheep and pigs) living at any one time is three times greater than the number of humans. The volume of manure produced by the 70 billion animals processed by the global food system each year is equivalent to the waste produced by twice the entire human population.
While governments typically have strict regulations for human waste, animal waste from industrial farms and slaughterhouses remains vastly under-regulated. The scale and extent of the problem is severe but under-reported. How protein companies manage – or mismanage – animal waste has significant implications for human health, climate change and biodiversity loss. A company’s continued licence to operate can also be impacted as regulations around the world become stricter.
Animal waste naturally contains nitrogen and phosphorus, two key nutrients most plants need to survive. The presence of these nutrients in animal manure means it has long been regarded as an effective fertiliser for plant growth.i However, manure is often either disposed of at the lowest cost, becoming a potential pollutant, or applied in a way that increases the risk of pollution.
Manure is costly to transport, so it tends to be applied within five kilometres of where it is produced, leading to concentrated areas of manure production and application on fields, which create nutrient hotspots. This problem of nutrient excess is exacerbated by the application of synthetic fertilisers on livestock crops, which take up a third of the planet’s arable land. When excess nutrients enter bodies of water, they can cause eutrophication, where excess growth of oxygen-depleting organisms damage ecosystems, by creating algal blooms, for example.
Slaughterhouses can also pollute the environment by discharging inadequately treated wastewater containing excessive nutrients into local waterways.
Agricultural waste and pollution: A multifaceted problem
Methane produced from manure storage and processing represents an estimated 10% of the total emissions from global livestock.
Manure from livestock is one of the main global sources of heavy metal contamination. High levels of antibiotics and antibiotic-resistant bacteria are consistently found in soil and water near livestock farms.
Slaughterhouses in the US discharge the highest phosphorus levels and the second-highest nitrogen levels of all industrial categories in the country.
Almost three quarters of US slaughterhouses that discharge pollution directly into rivers and streams are within one mile of under-resourced or low-income communities or communities of colour.
Types of animal waste and pollution
Animal waste from concentrated feeding operations can contain contaminants, pathogens, growth hormones, antibiotics, chemicals, animal blood and more, risking water contamination while emitting greenhouse gases (GHGs).
Types of animal waste pollution include:
Animal waste runoff
Waste can enter groundwater and subsequently the drinking water sources of humans and livestock, polluting them with a high concentration of nitrates. Large-scale production of animal waste and its surface application to soils has also been shown to cause an increase in the concentration of pollutants such as ammonia, which turns into nitrous oxide, further driving higher GHG emissions.
Animal waste odour
Livestock waste is also a source of malodours, originating from livestock buildings, storage, and the field application of animal manure. The intensity of the smell is often unacceptable, especially where there are residential areas close by, and communities impacted by such odours have pursued legal action to push for redress. For example, in July 2025 a Spanish court ruled that national and regional authorities had breached residents’ human rights and made their lives “unfeasible”, due to their mismanagement of pollution from industrial pig and poultry farms over several decades.
The High Court of Galicia ruled that the authorities must immediately adopt measures to guarantee the end of odours and the environmental degradation of the Las Conchas reservoir and its surroundings, measures which will potentially impact how industrial farms operating in the region treat and discharge of their animal waste.
Agricultural waste and pollution regulations
A lack of regulation and enforcement around waste management has favoured the expansion of intensive animal agriculture, but governments and international bodies are now beginning to legislate to reduce pollution from livestock farming:
The EU has been acting on its 1991 Nitrates Directive, which requires member states to monitor their waters and identify the effects of pollution from agriculture, referring Spain to the Court of Justice of the European Union after algal blooms in Mar Menor were linked to the region’s pork production, for example.
The EU´s Farm to Fork strategy targets a 50% reduction in nutrient losses to the environment by 2030.
Lawsuits and community opposition in relation to ecosystem degradation and biodiversity loss are also becoming more common, particularly in the US:
The city of Des Moines brought legal action against the state of Iowa, accusing it of not doing enough to control nutrient runoff and protect the Raccoon River from pollution.
In the UK, FTSE-listed protein producer Cranswick had an application to build one of the largest poultry and pig farms in Europe rejected, due to environmental concerns, including air and water pollution.
Residents submitted more than 12,000 objections, while 42,000 people signed a petition against the proposed expansion, showing how companies are risking their social license to operate if they are deemed to not sufficiently address such issues.
Managing risks throughout the production process
It is important that companies identify and disclose high-risk locations, set quality and volume targets at their facilities and engage with suppliers on nutrient pollution management.
More advanced practices entail year-on-year improvements for processing facilities, including an overall decrease in wastewater discharged and an increase in the quality of wastewater. Companies could also look to provide comprehensive guidance, technical support and incentives to suppliers to improve nutrient management.
Animal waste must be carefully disposed of to avoid harm to waterways and the wider environment. Pooling waste in deep pits or manure lagoons has been common for years due to their low costs and convenience. However, converting livestock waste into environmentally friendly products, such as biogas and compost, is now seen as a preferred alternative.
The rise of biogas
Methane’s global warming potency is 27 times that of carbon dioxide, and livestock is responsible for around 44% of human-made methane emissions. As such, there has been a growing focus on cutting down agriculture’s methane emissions to meet the pledge made by global leaders at COP26 to reduce methane emissions by 30% by 2030. This has driven the adoption of biodigesters in intensive animal farming to produce biogas.
While capturing methane from waste lagoons to produce biogas is recognised as better environmental practice than simply allowing methane to be emitted, leakages during digestion, transport and storage may mitigate the associated climate benefits.
Why are waste and pollution material financial risks for investors?
Poor waste management exposes animal protein producers to potential financial, regulatory, and social backlash. Although there are some examples of good practice in the industry, many companies are not managing waste responsibly. These firms face increased scrutiny about the impact of waste on surrounding communities and the environment. Assessing and managing risks associated with inadequate waste management throughout the livestock production process can help companies mitigate such scrutiny while demonstrating to investors that they have supply chain visibility.
Summary
The waste and pollution produced by intensive animal agriculture creates significant short- and long-term impacts with local and global implications. While this is a relatively unregulated area, legislation to control agricultural waste and pollution is on the rise worldwide. The risks associated with agricultural waste and pollution should be proactively managed by producers and scrutinised by investors.
Reference
[1] Dall, C. (2019). Antibiotic resistance in farm animals tied to global hot spots. CIDRAP.
[2] Des Moines Register. (2017). Des Moines Water Works won’t appeal lawsuit.
[5] FAO. (2006). Livestock’s long shadow: Environmental issues and options.
[9] Fleming, R., & Ford, M. (2001). Human versus animals – Comparison of waste properties.
[13] New Scientist. (2021). COP26: 105 countries pledge to cut methane emissions by 30 per cent.
[18] Statista. (2023). Soybean production worldwide 2012/13–2022/23, by country.
[19] Thornton, A. (2019). This is how many animals we eat each year. World Economic Forum.
[20] US Environmental Protection Agency. (2021). Meat and poultry products effluent guidelines.
