5 Agricultural Pollution Examples and Their Attributes Discussed
Agricultural pollution examples are; water pollution by influx of sediments loosened/exposed by overgrazing and over-tillage, air pollution by toxins from burning agricultural waste and biofuel, eutrophication by excessive fertilizer-accumulation, discharge of pathogenic agricultural effluents, and livestock methane emissions.
This article discusses agricultural pollution examples, as follows;
1). Water Pollution by Influx of Sediments from Agricultural Lands (as one of the Agricultural Pollution Examples)
One of the environmental issues associated with agricultural practices is the influx of sediments into aquatic ecosystems like marine water-bodies, lakes and ponds, as well as other environmental systems where these sediments occur as pollutants.
Here, 'sediments' include all forms of earth materials that can be displaced by erosion, and transported in runoff, into water bodies that could become degraded and unsafe, as a result.
There are multiple ways in which agriculture can lead to sediment influx.
Intensive farming can play a role in loosening the soil in agricultural lands. Excessive tillage or cultivation not only destroys soil structure, but loosens the sedimentary particles that comprise soil, thereby making the soil more vulnerable to the action of erosive agents .
Over-tilled soil is mechanically unstable, easily leached and eroded by water or wind. These same agents may transport the soil into nearby aquatic systems, to cause agricultural-water pollution.
Another agricultural practice that can cause sedimentary pollution of water is overgrazing.
Allowing herbivorous livestock to graze without regulation on a given area of land, leads to an acute loss of vegetation and fertility, which also make the land vulnerable to erosion .
Compaction of soil due to constant trampling by grazing livestock, will strip the soil of its structural integrity, along with its water retention capacity in most cases. This increases the likelihood of soil particle being displaced and transported in runoff from precipitation or irrigation water.
Sediment influx is hazardous because it reduces solar penetration in aquatic ecosystems.
Since light from the Sun drives photosynthesis; its obstruction by sediments occurs along with a risk of reduction, of species richness and biodiversity; as a result of disrupted food chains.
Sediment influx can clog some crevices and small pools that serve as natural habitats for some aquatic organisms. The sediments may also affect the natural flow-trend of water bodies, so that the efficiency of oxygen and nutrient recycling may decline.
In many cases, sedimentary agricultural pollution doubles as chemical pollution, because incoming sediments could be contaminated with agro-chemicals like pesticides and fertilizers.
Solutions to agricultural pollution by sediment influx revolve around sustainable farming practices that help the farmer achieve soil conservation without compromising yield. Some of such practices are; rotational grazing, conservation tillage, and cover cropping.
2). Air Pollution by Toxins from Burning Agricultural Waste and Biofuel
Air pollution can be caused by the combustion of agricultural materials.
Two main groups of agricultural materials that can degrade air quality when burnt are; agro-waste and biofuel.
It is not very uncommon for waste materials like crop residue to be disposed off by burning.
Often, this occurs after harvest, as part of preparations for a new round or season of planting . Husks, stems, fibrous residue and plant debris are forms of plant biomass that can be produced as waste on farms.
Air pollutants from agricultural combustion processes include; sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOCs), and particulate matter (PM) .
Effects of these materials range from climate alteration to cardiovascular, neurological and cancerous health problems. These effects can impact public health and inhibit various sectors of the local and regional economy; including agriculture.
Combustion of biofuels like ethanol can also contribute to the occurrence of air pollution, because these materials come from organic sources, like crop residue and livestock manure.
While it is more common for carbon dioxide (CO2) (a greenhouse gas) to be emitted from biofuel combustion, other, potentially-toxic materials like carbon monoxide and sulfuric oxides can also be emitted, especially in cases involving incomplete combustion and/or low-quality biofuel.
3). Eutrophication by Excessive Fertilizer-Accumulation (as one of the Agricultural Pollution Examples)
Eutrophication is simply the accumulation of excessive amount of nutrients like phosphorus and nitrogen, in water bodies.
The evidence of this type of water pollution is rapid and unnatural growth of algae in the water, leading to altered biogeochemical cycling, water quality and biodiversity.
While it sometimes occurs naturally, the manmade form of eutrophication is more common and severe.
Under natural circumstances, eutrophication can occur when leaching, weathering and erosion have extracted minerals from parent rock material, and these minerals have accumulated to high concentrations in water bodies.
Human activities that cause eutrophication are overwhelmingly linked to agriculture.
Lands on which fertilizers have been applied to boost soil fertility, are potential sources of nutrients that could be eroded and transported (usually along with sediments), into adjacent rivers, lakes and streams.
Because of its negative social, economic and environmental impacts, efforts and recommendations are constantly being made to address eutrophication challenges. These include the replacement and minimal use of synthetic fertilizer, and the use of buffer strips to intercept as well as filter nutrient-enriched runoff.
4). Discharge of Pathogenic Agricultural Effluents
Agricultural effluent is simply liquid-state waste material, also called 'wastewater', that is produced as a result of agricultural activities, such as irrigation, equipment-cleaning, food processing, and livestock production.
Because agricultural effluents are rich in organic matter and nutrients within a fluid medium; they are an ideal ground for the growth and reproduction of many pathogenic microorganisms. This means that exposure to such waste can be harmful to both biotic and abiotic components of the environment.
Exposure is highly possible, if agricultural effluents are not carefully managed. This is why pathogenic-microbial pollution is a major concern in agriculture, not only for the sake of farmers, crops and livestock, but also with respect to the health and wellbeing of organisms in the external environment.
Pathogens that can be transmitted in agricultural effluents include disease-causing species of viruses and bacteria.
Scenarios that are behind pathogen-spread in agriculture include; improper storage, treatment and disposal of wastewater. Under such conditions, pathogens can get into irrigation water, or into the outflow-stream of waste.
Because they (pathogens) are generally persistent, they often survive and even reproduce in any medium into which they are introduced, thereby becoming more potent and harmful as parasites and disease-vectors.
It must also be noted that pathogens from agricultural waste can be transmitted to plants, lower animals and humans by consumption of contaminated water or food, physical contact, or aerosol-inhalation.
Examples of pathogens in agricultural effluent are;
1. Viruses like Hepatitis A.
2. Bacteria like Salmonella spp. and Campylobacter 
3. Protozoan parasites like Giardia
Agricultural pathogens and their health consequences have increased the general degree of awareness on agricultural pollution, and the need to carefully manage all forms of agricultural waste.
5). Livestock Methane Emissions (as one of the Agricultural Pollution Examples)
Livestock methane emissions can be described as the act and process of methane release from livestock farming materials, and metabolism.
The issue of livestock methane emission is a serious one because methane (CH4) is itself a highly-potent greenhouse gas, that is more effective than carbon dioxide (CO2) in its contribution to global warming .
Ruminant enteric fermentation is the biggest source of methane emission from the agricultural sector. This process involves enzymatic and microbial breakdown (also called anaerobic digestion) of plant materials in the rumen of cattle like goats, cattle and sheep . Methane is generated as a byproduct, and released through flatulence and eructation.
Methane emissions increase the carbon footprint of livestock farming, and can be viewed as a form of agricultural pollution since methane is introduced as a foreign material into the atmospheric gas stream.
Livestock can also emit methane through biodegradation of their waste.
Measures that can be taken to reduce methane emissions from livestock include methane-capture and utilization, genetic selection, optimal manure management, and change of feed content/quality.
Examples of agricultural pollution are;
1. Water Pollution by Influx of Sediments from Agricultural Lands
2. Air Pollution by Toxins from Burning Agricultural Waste and Biofuel
3. Eutrophication by Excessive Fertilizer-Accumulation
4. Discharge of Pathogenic Agricultural Effluents
5. Livestock Methane Emissions
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