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Nitrogen pollution

Topics Covered:

  1. Conservation, environmental pollution and degradation, environmental impact assessment.

 

Nitrogen pollution

 

What to study?

For Prelims and Mains: Nitrogen- natural cycle, pollution and ways to prevent it, South Asian Nitrogen Hub.

 

Context: A major international research programme is being carried out to tackle the challenge that nitrogen pollution poses for environment, food security, human health and the economy in South Asia. The research programme will be carried out by South Asian Nitrogen Hub.

 

South Asian Nitrogen Hub:

  • The South Asian Nitrogen Hub, a partnership led by the UK’s Centre for Ecology & Hydrology and comprising around 50 organisations from across the UK and South Asia, will be established with funding from UK Research and Innovation (UKRI) under its Global Challenges Research Fund (GCRF).
  • The Hub is one of 12 GCRF hubs announced by the UKRI to address intractable challenges in sustainable development. The interdisciplinary hubs will work across 85 countries with governments, international agencies, partners and NGOs.
  • India is a major partner with 18 Indian institutions in this project. India is the only country in South Asia that has completed its nitrogen assessment over a year ago and is already co-leading the South Asian nitrogen assessment with CEH, UK, for the UN Environment.

 

Nitrogen as an essential nutrient:

Nitrogen, which is a vital macronutrient for most plants, is the most abundant element in the atmosphere.

A little over 78% of dry air on Earth is nitrogen. But atmospheric nitrogen, or dinitrogen, is unreactive and cannot be utilised by plants directly.

Until the beginning of the 20th century, farmers depended on a natural process called nitrogen fixation for the conversion of atmospheric nitrogen into reactive nitrogen in the soil: nitrogen-fixing bacteria like rhizobia live symbiotically with leguminous plants, providing nitrogen to the plant and soil in the form of reactive compounds like ammonia and nitrate.

But the natural nitrogen cycle was inadequate to feed the growing population. Scientists Fritz Haber and Carl Bosch solved this problem by producing ammonia by combining atmospheric nitrogen with hydrogen gas at high temperature and pressure—known as the Haber-Bosch process. The Green Revolution, which was instrumental in establishing food security in the developing countries in the 1960s, was driven by artificial nitrogen-fixation. Today, about half of the world’s population depends on this process for its nutrition.

 

How Nitrogen turned into pollutant from nutrient how it is affecting health and environment?

Nitrogen is an inert gas that’s necessary for life. But we’re changing it into forms that are harmful, overloading the environment with it, and throwing the natural nitrogen cycle out of whack.

Nitrogen compounds running off farmland have led to water pollution problems around the world, while nitrogen emissions from industry, agriculture and vehicles make a big contribution to air pollution.

Over 80% of the nitrogen in soil is not utilised by humans. While over four-fifths of the nitrogen is used to feed livestock, only about six per cent reaches humans in case of non-vegetarian diet, as compared to the 20% that reaches the plate of a vegetarian.

Nitrogen becomes a pollutant when it escapes into the environment and reacts with other organic compounds. It is either released into the atmosphere, gets dissolved in water sources such as rivers, lakes or groundwater, or remains in the soil. While it might lead to favourable growth of species that can utilise this nutrient, nitrogen as a pollutant is often detrimental to the environment and health.

According to the World Health Organization, nitrate-contaminated drinking water can cause reduced blood function, cancer and endemic goiters. Surplus inputs of nitrogen compounds have been found to cause soil acidification. The lowering pH, as a result of the acidification, can lead to nutrient disorders and increased toxicity in plants. It may also affect natural soil decomposition.

 

Nitrogen pollution has a significant impact on the environment:

  • It creates of harmful algal blooms and dead zones in our waterways and oceans; the algae produce toxins which are harmful to human and aquatic organisms (and indirectly affects fisheries and biodiversity in coastal areas).
  • Contamination of drinking water. 10 million people in Europe are potentially exposed to drinking water with nitrate concentrations above recommended levels. This can have an adverse effect on human health.
  • Food Security: Excessive nitrogen fertiliser application contributes to soil nutrient depletion. As the world needs to feed an ever growing population loss of arable land is major global problem.
  • The release of Nitrous Oxide is essentially a greenhouse gas which is harmful to the environment.

 

Sources: the hindu.

Mains Question: Air Pollution in India can no longer be tackled with short term, reactive solutions. Critically analyze.