When large numbers of animals are farmed intensively in industrial units in an attempt to maximise financial gain this is known as factory farming. During the second half of the twentieth century agricultural practices went through massive changes, particularly in mechanisation, the use of chemicals and large-scale intensive farming.
As a result of increasing the density of domestic farm animals, reported farm pollution incidents have remained high and farm waste remains a major problem. In some countries about half of all serious water pollution incidents are from manure runoff from farms. Poultry, cows and pigs are the farm animals most responsible for the pollution. Livestock production occupies 70% of all land used for agriculture and 30% of the planet’s land surface. It is responsible for 18% of the world’s greenhouse gas emissions as measured in CO2 equivalents. It also generates 64% of the ammonia, which contributes to acid rain and acidification of ecosystems.
Farm waste is a mixture of animal faeces and urine, plus milk and chemicals such as pesticides. A large quantity of animal waste is generated by concentrated animal feeding operations and disposal of the waste has been a major problem. Factory farms collect the animal waste and mix it with water to form slurry. Slurry is a type of liquid manure that can be used on fields as fertiliser. If the soil or plants are unable to absorb the slurry or if the slurry is spread in too high a concentration, the run-off can get into water systems.
Slurry is generally more polluting than raw sewage. When slurry tanks are accidentally or deliberately breached large amounts of slurry can spill into rivers, streams or lakes, including wetlands causing severe environmental problems. Many incidents are not reported. Animal waste is found in soil, surface water, groundwater and sea water.
Slurry disturbs aquatic ecosystems by increasing nitrogen and phosphorus levels leading to the growth of toxic algae, which poison the fish and it decreases oxygen levels causing fish to suffocate.
Farm waste has led to the development of parasitic infections on frogs, which have become severely deformed, growing without hind legs or with up to six extra limbs.
The growth of toxic algae in waterways is called algal blooms. In addition to the ecological effects these algal blooms make waterways smelly, unsightly, unsuitable for drinking and dangerous for swimming.
Increased use of agrochemicals, farm machinery and irrigation in recent years has made the pollution problem worse.
Milk spills are another major environmental hazard for aquatic ecosystems. Milk is a highly polluting substance and when it gets into waterways is a threat to fish and other animals living within the waterway. This is because the bacteria feeds on the milk and uses up oxygen that fish and other animals need to survive. The dairy industry sometimes accidentally loses huge volumes of milk from its tankers. Sometimes milk that cannot be sold is deliberately dumped and gets into waterways.
Chemicals used on farms as pesticides, fungicides or fertilisers are found in waterways. Common farm chemicals include 1080, aluminium phosphide, cresol, organophosphorus pesticides, pyrethroids, methyl bromide, strychnine, and tryquat. These chemicals are sprayed on farmland using tractors and boom sprayers, or aerial sprays from light planes. Droplets are produced that can linger in air and may be carried by wind away from the intended area. This is known as ‘spray drift’. Chemical spray drift cannot always be contained and might still occur despite correct application. These chemical sprays often drift over neighbouring properties or waterways and can affect human health, animals and the environment.
Factory farmed animals are given antibiotics in their food to prevent infection in their overcrowded conditions. Animal waste contains substantial amounts of bacteria, and because only about a quarter of the antibiotic is digested by an animal, the waste may also contain antibiotics. This combination is a perfect opportunity for the development of antibiotic-resistant bacteria, which may pass to humans when water or soil is contaminated with the bacteria from farm waste. Vegetables and fruit can also become contaminated with antibiotic-resistant bacteria if animal waste that contains the bacteria is spread onto agricultural fields of fruit or vegetables.
Many farmers in developing countries want to maintain traditional farming methods which are often better for the environment, but competition from corporations contributes to making this unviable, forcing small farmers into large-scale farming or condemning them to poverty.
Permaculture and small-scale organic farming are a better alternative to monocultures and factory farming. But these systems are still only models for farming and are not being used. There is still a long way to go before agriculture as a whole is environmentally sustainable.
We need more government controls on farming-related pollution and waste. There are measures that can be taken to ensure that manure from farms is treated and does not reach waterways and pollute them. There should be improvements in farm practices through an appropriate combination of: educating landowners and land managers; providing funds for improvement programs; offering incentives and subsidies; improving regulations and better enforcement of them.
In the United States "factory farms" have been ordered to manage their manure and wastewater better and to apply for water run-off permits. In Australia, new initiatives such as the farm waste factory in Gunnedah, New South Wales, provide innovative solutions to the farm waste problem. At the new factory, waste will be recycled to produce charcoal beads, which can be used as water harvesters, and soil improvers.
Education about how to transport, store, use and dispose of chemicals more safely, and chemical disposal services such as Chem-clear have helped reduce chemical pollution.
Farm waste has huge potential as a source of energy. It is a major source of methane, a greenhouse gas contributing to climate change. When possible the methane should not be allowed to escape into the atmosphere. It should be captured and the energy potential should be harnessed.
What you can do
Report any farm waste pollution to your local water authority. Many industries have licences from the environmental regulatory body relating to their operations and waste. The licence is usually publicly available upon request and indicates what is supposed to be done.
If you have gardens, support local farmers who sell their farm waste as an alternative to chemical fertilizers.
Write a letter or email to the editor of your local newspaper and urge them to publish your concerns about local farm waste issues.
If you live near or on a waterway, ensure you don’t pollute this by over use of farm manures you place on your garden.
Write a letter or email your government representative, urge him or her to take action to protect waterways and manage farm waste in a more sustainable way.
Be careful in the use, transportation, storage and disposal of chemicals. Minimise or eliminate their use by applying organic alternatives in your farming practises wherever possible.
As a consumer, support farmers who take their responsibility to the environment seriously. Consider adopting a vegetarian diet. If you eat meat, dairy products or eggs try to buy organic, free-range produce from small, local farms.