The Consequences of Nitrogen Pollution
Nitrogen is essential to all life on
earth as it forms an important component of life-building and propagating
biochemical molecules like proteins.
But overuse in agriculture in the form
of fertilisers and other fields are the deadly cause of pollution.
Excess nitrogen pollution has
tremendous consequences on humans and the environment.
In the form of nitrous oxide, for
example, it is 300 times more powerful than carbon dioxide as a greenhouse gas,
in addition to the effects of various nitrogen compounds on air quality and the
ozone layer.
Altogether, humans are producing a
cocktail of reactive nitrogen that threatens health, climate and ecosystems,
making nitrogen one of the most pollution issues facing humanity.
Excessive use of nitrogen-rich
fertilizer in India and its impact
It is a sensitive issue given that
India’s food self-sufficiency owes a lot to the use of urea that ensured high
yields. But society conservation nature, a coalition of more than 120
scientists with varied expertise, took a call to launch an in-depth scientific
probe in 2006 with setting up of a specialized group called the Indian Nitrogen
Group.
They study not just the nitrogen being
used for agricultural processes but also its increasing emissions from the
transport boom in the country.
Annual Frontier Report 2019 Published
by the United Nation (UN)
The annual Frontier Report 2019
published by the United Nations, has included a chapter on nitrogen pollution
in its latest edition. The report was released by the United Nations
Environmental Assembly (UNEA) in Nairobi.
According to the report pollution
caused by reactive forms of nitrogen is now being recognized as a grave
environmental concern on a global level.
Increasing demand in livestock, agriculture,
transport, industry and energy sector has led to sharp growth of the levels of
reactive nitrogen- ammonia, nitrate, nitric oxide (NO), nitrous oxide (N2O) in
ecosystem.
The report claims that the total annual
cost of nitrogen pollution to eco system and healthcare services in the world
is around 340$ billion. The report also warns that scale of the problem remains
largely unknown and unacknowledged outside scientific circles.
Nitrogen Pollution Impacts- Algae
Blooms
Nitrogen makes plants grow. When too
much nitrogen flows to bays, fast-growing plants out-compete and kill slower
beneficial plants. Decaying plants don’t produce oxygen, which kills fish and
other marine life. Algae blooms such as brown tide, rust tide, and the
macro-algae called Ulva, (AKA Sea lettuce).
Poisonous for people and wildlife
The red tide algae Alexandrium produces
a powerful neurotoxin that accumulates in filter feeding shellfish that can
poison the people or wildlife that eat them. Toxic algae are increasingly
occurring in long island’s bays and harbours.
Why nitrogen is 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 uncreative and cannot be utilized 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 atmosphere 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.
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.
Effects on health
According to the World Health
Organization, nitrate-contaminated drinking water can cause reduced blood
function, cancer and endemic goitres. 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.
The Nitrogen is a 'pollutant'
India has become the third
country/entity after the US and the European Union have assessed the
environmental impact of nitrogen on their respective regions
comprehensively.
The assessment shows that agriculture
is the main source of nitrogen pollution in India. Within agriculture, cereals
pollute the most.
How does agriculture produce nitrogen pollutants?
Rice and wheat take up the maximum
cropped area in India at 36.95 million hectares and 26.69 million hectares
respectively.
India consumes 17 million tonnes of
nitrogen fertiliser annually as per the data of the fertilizer association of
India.
Only 33% of the nitrogen that is
applied to rice and wheat through fertilisers is taken up by the plants in the
form of nitrates (N03).
Unfortunately for India, agriculture is
just one of the sources of nitrogen pollution,
Sewage and Organic Solid Wastes- The Second Largest
Sources of Nitrogen Pollution
Sewage and organic solid wastes form
the second largest sources of Nitrogen pollution in India.
While this may not be so in developed
countries with better system for sewage and solid waste management, including
recovery of nutrients from them, it is one of the fastest growing sources of
Nitrogen pollution in India.
Vehicles also Contribute NOx
Vehicular pollution is also a major
contributor of NOx, accounting for 32% of the total emission in India, out of
which 28% is from road transport. In Delhi, the share of road transport
shoots up to the range of 66 to 74%.
Therefore, there is an urgent need to curb the nitrogen pollution, and act upon it. Individual attention can help in reducing the use of vehicles which produce Nitrogen, and proper education will help people in using appropriate fertilisers. For everything, government can not be entirely responsible, in the end - its we, are the people, who can manage to bring the change.
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