Do artificial fertilizers contaminate our food chain?

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Artificial Fertilizers Contaminate Food Chain is a pressing concern that demands our immediate attention. As we nourish our farmlands with synthetic inputs, it’s crucial to understand the fate of these fertilizers once they’ve served their purpose. Do plants break them down into harmless products, or do they persist, contaminating our food and ultimately poisoning our bodies? If artificial fertilizers indeed contaminate the food chain, we must reconsider their widespread use. However, it’s essential to examine whether we can generalize all artificial fertilizers and address this issue comprehensively. This discourse investigates these questions and more, shedding light on the intricate relationship between artificial fertilizers and our food systems.

What are fertilisers? 

Fertilisers are substances that farmers can use to make their crops grow faster and more abundantly. 

They can be natural (e.g. compost, manure, fermented nettles) or synthetic (e.g. ammonium sulphate, superphosphate, potassium chloride) that includes PFAs (per and polyfluoroalkyl substances). 

Why don’t we fertilise the rainforest? 

Have you ever noticed that nobody needs to add fertiliser to the rainforest for it to flourish? It’s one of the most productive ecosystems on earth, but it doesn’t stop growing if nobody applies synthetic nitrogen to it. 

That’s because of nutrient cycling. 

A process by which nutrients are transferred from the environment to one or more organisms and then returned to the environment by decomposition and death. 

This includes the nitrogen cycle and the phosphorus cycle. 

That’s because nutrient cycling naturally occurs in healthy ecosystems. 

Plants capture sunlight and water to create energy in a process called photosynthesis. 

The plant uses some of this energy directly but converts the rest to carbohydrates and proteins, which the roots pump into the soil to feed microorganisms like bacteria and fungi. 

Why feed the little guys? In return, those microbes protect plants from disease, help them access water, and retrieve nutrients locked up in rock particles within the soil.

In a wild setting, the waste from plants (e.g., fallen leaves and dead branches) and wildlife (e.g., manure and antlers) would fall to the ground, releasing nutrients back into the soil. 

This nutrient cycling isn’t so simple in a farm setting. 

When we harvest crops, we also remove the vitamins and minerals inside that plant material. 

And most farmers would prefer to prevent deer from eating and sleeping in their crops. 

That’s a good thing for anyone who doesn’t grow all their own food. 

When we go to the supermarket, we benefit from the nutrient-dense foods farmers provide. 

But for soil and the billions of organisms that call it home, interrupting the nutrient cycle can take a toll. And if soil health and fertility decrease, we undermine our ability to produce healthy food in the long run. 

Luckily, microbes can extract nutrients from rock particles in the ground so long as they have good living conditions. 

So, it is possible to maintain nutrient levels without synthetic fertilisers if we take care of soil health with techniques such as minimising disturbance (avoid ploughing that can kill soil life) and “keeping a living root in the ground”. 

That could look like planting a cover crop we don’t intend to harvest to ensure food for microbes flows year-round into the root zone. (Instead of leaving the soil bare in the months we’re not growing a crop). Additionally, the manure of grazing animals is a nutrient-rich, natural fertiliser. 

Grazing animals must be managed sustainably so they don’t cause nutrient pollution, overgraze or compact the soil. 

But natural fertilisers like manure can have a lower environmental impact than synthetic alternatives when livestock are sympathetically integrated into a healthy farm. 

The benefits of synthetic fertilisers. 

Humans have been around a lot longer than nitrogen fertilisers. So, we clearly didn’t need synthetic inputs to produce food before they were invented. What’s different today? 

We need to feed an enormous population. At the same time, the percentage of the population working in agriculture has steadily fallen since the 1930s. – Statista (2023) 

Fertilisers are a valuable tool in a world where fewer people need to grow more food and do it cheaply to stay competitive in the global market. Some estimates suggest that nearly half of people alive today are dependent on synthetic fertilisers. 

This is largely because of fertilisers’ incredible success in boosting critical crop yields. 

Increased yields mean we can produce more food in a smaller surface area, preventing land use change like deforestation (At least in the short run). 

We have seen a decline in 69% of measured wildlife populations in the last 53 years alone. – WWF (2022) “Living Planet Report 2022”. So, preserving remaining wild habitats is essential. 

And it’s not just a matter of ethics; it’s about human survival. Biodiverse habitats like forests, wetlands, and wood meadows sequester carbon, regulate our climate, shelter communities from natural disasters, and protect our most precious resource – water. 

Some data suggests that over 1.5 billion hectares of land have been spared from agricultural conversion thanks to increased crop yields. 

Artificial fertilisers can also be cheaper than organic soil amendments and often act more quickly on the plant than natural choices. So synthetic fertilisers might be a sensible choice if a farmer is concerned with shorter-term crop health, e.g., if they are desperate to make it through the next harvest. 

Tanzania imports more than 90% of its fertilizers, with the most common being urea, di-ammonium phosphate (DAP), calcium ammonium nitrate (CAN), and nitrogen-phosphorus-potassium (NPK) blends. In 2021, Tanzania imported 395,033 metric tons of fertilizer, which was a 40% decrease from 2020. 

This was due to high fertilizer prices on the world market. Urea, DAP and NPK has been the most imported fertilizers to Tanzania over the years. 

In 2021, there were more imports of CAN than DAP which used to be the second most imported fertilizer after Urea. Tanzania fertilizer imports decreased by 40% from 662,868mt in 2020 to 395,033mt in 2021. 

In 2021, Tanzania consumed 9.2503 kilograms of fertilizer per hectare of arable land. 

However, the application rate per hectare in Tanzania is still low, at 15.858 kilograms, which is below recommended levels. 

Tanzania dependency on the exports will ease after the completion of the artificial fertiliser factory now being constructed to utilise Songo Songo natural gas.

Nitrogen-fixing chemical processes, such as the Haber process invented at the beginning of the 20th century, and amplified by production capacity created during World War II, led to a boom in using nitrogen fertilizers. In the latter half of the 20th century, increased use of nitrogen fertilizers (800% increase between 1961 and 2019) has been a crucial component of the increased productivity of conventional food systems (more than 30% per capita) as part of the so-called “Green Revolution”. 

The use of artificial and industrially-applied fertilizers has caused environmental consequences such as water pollution and eutrophication due to nutritional runoff; carbon and other emissions from fertilizer production and mining; and contamination and pollution of soil. 

Various sustainable agriculture practices can be implemented to reduce the adverse environmental effects of fertilizer and pesticide use and environmental damage caused by industrial agriculture. 

The introduction of human waste or sludge fertilizers was hailed for recycling human waste but recent studies have questioned the suitability of that approach. 

In the modern food chain, modernization of cooking, eating utensils have also come under scrutiny that byproduct contaminants may be ingested and excreted by humans. 

Human excreta and urine once contaminated may proceed to contaminate plants that human, livestock and wild animals eat compromising the whole food chain. 

While we applaud scientific breakthroughs such as non-stick cooking pots, stain resistant carpets and others have been found to get diluted or scrubbed in a manner that contaminates our foodstuffs. 

Once in the human body, these harmful chemicals called “forever chemicals” that were used to manufacture the said products we like and use may cause cancer, birth defects and much more hazards. 

So, when human sludge that is contaminated with harmful chemicals are used to produce artificial fertilisers the whole food chain becomes compromised. Artificial fertilisers is assimilated by plants to provide them with the nutrients they need for growth and survival. 

Studies have also indicated that drugs we use to protect ourselves from diseases or for family planning do find their way into human excreta and urine. 

Such by products once in artificial fertilizers will be assimilated by plants, and joining in our food chain. The consequences of all thos is still a study in its nascent stages but may explain chronic resistance to drugs, infertility, birth defects, cancers and much more. 

Should artificial fertilisers be banned because disadvantages are more than the advantages? 

Depending on whom you ask the answer to that may not be straightforward. 

What is straightforward is we need regular testing of sludge and other materials used to manufacture artificial fertilisers to ensure we understand what we are getting ourselves into.

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