Mineral Fertilizer Use and the Environment International Fertilizer Industry Association United Nations Environment Programme

7.1. Drinking water
In the mid-1980s the World Health Organization
(WHO) recommended a limit of 50 mg of nitrate,
NO
3
, per litre of drinking water. They reviewed
the recommendation in April 1997 and
concluded that, on the basis of the latest scientific
evidence, the value of 50 mg per litre should be
maintained.
The European Union (EU) issued a drinking
water directive in 1975. In 1980 another
directive set a level of 50 mg per litre. Then, in
December 1991, the EU adopted a directive,
known as the Nitrates Directive, concerning the

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Mineral Fertilizer Use and the Environment
be made between correct nitrogen fertilization
and excessive animal excrement application.
There is generally little danger of the nitrate
pollution of ground water due to the application
of fertilizer on rain-fed crops in developing
countries, both because the application rates tend
to be well below the optimum. In irrigated
agriculture, water management is an important
issue.
Section 12.1.1. “Nitrates” of this publication
concerns the human health issue of nitrates.
7.2. Surface waters
The over-enrichment of surface waters leading to
an excessive multiplication of algae and other
undesirable aquatic plant species, with various
undesirable consequences, is a phenomenon
known as eutrophication. Whereas phosphate
tends to be the limiting nutrient in inland waters,
nitrogen tends to be the limiting nutrient in
coastal waters.
7.2.1. Coastal waters
In Europe large areas of the North Sea coastlines
and areas of the Mediterranean have suffered
from eutrophication due to nitrates. In the USA,
nitrates and phosphates are suspected of causing
Hypoxia, or the “Dead Zone” in the Gulf of
Mexico. There is a great deal of controversy as to
the cause, and even if these nutrients prove to be
the cause, they may originate from several
different sources apart from mineral fertilizers.
Nutrient-enriched water, especially run-off from
agriculture, is also incriminated in the Pfiesteria
problem that killed a large number of fish in
Chekaspeake Bay, USA, in the summer of 1997.
It is highly unlikely that mineral fertilizers are
primarily responsible for either of these problems,
but the U.S. fertilizer industry is co-operating fully
in the investigations.