Agricultural pollution
Agricultural pollution refers to biotic and abiotic byproducts of farming practices that result in contamination or degradation of the environment and surrounding ecosystems, and/or cause injury to humans and their economic interests.
Pollutants from agriculture greatly affect water quality and can be found in lakes, rivers, wetlands, estuaries, and groundwater.
For example 2,4-D and atrazine have with lifetimes up to 20 years—such as DDT, aldrin, dieldrin, endrin, heptachlor, and toxaphene), or even permanent (as seen in substances like lead, mercury, and arsenic).
[9] The extent to which the pesticides and herbicides persist depends on the compound's unique chemistry, which affects sorption dynamics and resulting fate and transport in the soil environment.
While they are beneficial for plant growth, they can also disrupt natural nutrient and mineral biogeochemical cycles and pose risks to human and ecological health.
[16]Although leading to increased crop yield, nitrogen fertilizers can also negatively affect groundwater and surface waters, pollute the atmosphere, and degrade soil health.
Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause "blue baby syndrome" (acquired methemoglobinemia) in infants and possibly thyroid disease and various types of cancer.
Other significant processes in the nitrogen cycle are nitrification and ammonification which convert ammonium to nitrate or nitrite and organic matter to ammonia respectively.
[19] A common result of this in aquatic ecosystems is eutrophication, which in turn creates hypoxic and anoxic conditions – both of which are deadly and/or damaging to many species.
A greater amount of NOx compounds in the atmosphere can result in the acidification of aquatic ecosystems and cause various respiratory issues in humans.
Because of this, it typically enters surface waters when the soil particles it is attached to are eroded as a result of precipitation or stormwater runoff.
[27] In addition to depleting oxygen levels in surface waters, algae and cyanobacteria blooms can produce cyanotoxins which are harmful to human and animal health as well as many aquatic organisms.
Where high annual rates of phosphorus fertilizer are used, this can result in uranium-238 concentrations in soils and drainage waters that are several times greater than are normally present.
[31] Agriculture contributes greatly to soil erosion and sediment deposition through intensive management or inefficient land cover.
[44][45] However, the same paper noted that a shift from conventional to organic practices would likely be beneficial for long-term efficiency and ecosystem services, and probably improve soil over time.
[50] The United Nations Food and Agriculture Organization (FAO) predicted that 18% of anthropogenic greenhouse gases come directly or indirectly from the world's livestock.
While the FAO used a life-cycle assessment of animal agriculture (i.e. all aspects including emissions from growing crops for feed, transportation to slaughter, etc.
[51] Alternate sources [52] claim that FAO estimates are too low, stating that the global livestock industry could be responsible for up to 51% of emitted atmospheric greenhouse gasses rather than 18%.
The World Trade Organization has international regulations concerning the quarantine of pests and diseases under the Agreement on the Application of Sanitary and Phytosanitary Measures.
Potential ecological issues could include the dispersal from agricultural habitats into natural environments, and host-switching or adapting to utilize a native species.
In addition, predicting the interaction outcomes in complex ecosystems and potential ecological impacts prior to release can be difficult.
In order to prevent agricultural pollution, quarantine and extensive research on the organism's potential efficacy and ecological impacts are required prior to introduction.
For example, the increased use of herbicide in herbicide-resistant corn fields in the mid-western United States is decreasing the amount of milkweeds available for monarch butterfly larvae.
[62] Animal feeding operations produce about 100 times more manure than the amount of human sewage sludge processed in US municipal waste water plants each year.
Undiluted animal manure or slurry is one hundred times more concentrated than domestic sewage, and can carry an intestinal parasite, Cryptosporidium, which is difficult to detect but can be passed to humans.
Silage liquor (from fermented wet grass) is even stronger than slurry, with a low pH and very high biological oxygen demand.
With a low pH, silage liquor can be highly corrosive; it can attack synthetic materials, causing damage to storage equipment, and leading to accidental spillage.
[citation needed] Anaerobic digestion is the biological treatment of liquid animal waste using bacteria in an area absent of air, which promotes the decomposition of organic solids.
[64] The remaining liquid is nutrient rich and can be used on fields as a fertilizer and methane gas that can be burned directly on the biogas stove[65] or in an engine generator to produce electricity and heat.
[64][66] Methane is about 20 times more potent as a greenhouse gas than carbon dioxide, which has significant negative environmental effects if not controlled properly.
