So maybe eating less meat should help to eliminate pollution from the production of food right? Well, let us introduce to you the effects of agricultural pollution. This refers to the pollution caused, either biotically or abiotically, by the various farming and agricultural practices adopted. Let explore how seemingly green farms can be also pollutive to the environment.
Most farms today are utilising some sort of fertilisers, which can trace its roots back to the agricultural revolution. To meet the rising consumer demands, many farmers resort to fertilisers to keep their lands arable without giving it much rest time. These nutrient-rich fertilisers and chemicals then allow for high yields, even on overtaxed lands. However, using such fertilisers and chemicals have an impact ‘down the drain’ in our water and air resources.
High applications of nitrogen and phosphorus filled fertilisers can be lost through runoff and leaching into the groundwater, causing water pollution. An increase in nitrate (a byproduct when nitrogen fertilisers interact with water) level in groundwater have led to the ‘blue baby syndrome’ (acquired methemoglobinemia) in young children as well as other diseases such as typhoid and cancer (Ward et al., 2018). Similarly, phosphorus, being a limiting agent naturally, becomes the largest source for harmful algae and cyanobacteria blooms that cause eutrophication as they enter freshwater sources (Savci, 2012). Apart from reducing oxygen levels in the water, these blooms can also be toxic to animals and humans dependent on these water sources due to the release of cyanotoxins (US EPA, 2013).
Nitrogen fertilisers can also make nitrogen more bioavailable due to its form as ammonia (NH3), as compared to the natural nitrogen gas (N2) (Savci, 2012). This results in the nitrogen in the fertiliser also reacting with other things, apart from plants as well, causing the release of nitrous oxide, which is a strong greenhouse gas, or nitrogen oxide, which contribute to ground-level smog (Savci, 2012).
Heavy metals are also found in these fertilisers to aid with the growth of the crops. However, farming practices such as irrigation can lead to the accumulation of these metals such as Selenium, which is toxic to humans and animal lives, in downstream water sources. One of such examples is the Kesterson Reservoir in California,USA which was designated as toxic after high levels of Selenium released by fertilisers (Presser, 1994). Fertilisers can also be contaminated with other toxic metals, in order to reduce the cost of production when steel industry waste is recycled into fertilisers for its zinc content. This includes mercury and arsenic, which can contaminate food products and be detrimental to human lives when consumed (Mortvedt, 1996).
From this, we can witness how some of the farming practices contribute to the pollution of the environment. While many might think that having these ‘green’ spaces helps the environment, especially with absorbing of CO2, a greenhouse effect, we will explore why this line of reasoning might be flawed in our next post!
Trailing off,
Jade and Ridzuan
References
Mortvedt, J.J. (1996). Heavy metal contaminants in inorganic and organic fertilizers. Fertilizer Research, [online] 43(1–3), pp.55–61. Available at: https://link.springer.com/article/10.1007/BF00747683 [Accessed 31 Aug. 2020].
Presser, T.S. (1994). “The Kesterson effect.” Environmental Management, [online] 18(3), pp.437–454. Available at: https://zenodo.org/record/1232546#.X0zvaMgzZPY [Accessed 31 Aug. 2020].
Savci, S. (2012). Investigation of Effect of Chemical Fertilizers on Environment. APCBEE Procedia, [online] 1, pp.287–292. Available at: https://www.sciencedirect.com/science/article/pii/S2212670812000486 [Accessed 31 Aug. 2020].
US EPA. (2013). The Effects: Dead Zones and Harmful Algal Blooms | US EPA. [online] US EPA. Available at: https://www.epa.gov/nutrientpollution/effects-dead-zones-and-harmful-algal-blooms [Accessed 31 Aug. 2020].
Ward, M., Jones, R., Brender, J., de Kok, T., Weyer, P., Nolan, B., Villanueva, C. and van Breda, S. (2018). Drinking Water Nitrate and Human Health: An Updated Review. International Journal of Environmental Research and Public Health, [online] 15(7), p.1557. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6068531/ [Accessed 31 Aug. 2020].
