A healthy environment means a healthy generation!
‘Water not fit for drinking’. Many people do not know that no water is
simply water. There are many unseen substances dissolved which
makes water unsuitable for us to drink. Nonetheless, human activity,
mainly the use of fertilisers, is continually deteriorating our quality of
water.
Right now, the topic of nitrate leaching is a very widely-discussed topic
throughout the world, including in Malta. This is because lately a lot of
nitrates are leaching into the water table. Most of the Maltese aquifers
are contaminated. This happens when farmers put excess fertilizer in the
soil. Growing plants take only what they need. The remaining nitrates
are not absorbed by the soil, therefore they can easily be washed out of
the soil by rainwater or irrigation to end up in our precious water table.
This could cause a lot of damage, both to us humans and to the
environment. Nitrate in drinking water may cause stomach cancer in
adults and ‘blue-baby syndrome’ in infants. This is a condition where
infants who are less than a year old ingest too much nitrate. Nitrates are
also an environmental problem because not only land plants need them
to grow. Plants growing in water also respond to the nitrates like crops.
However their growth is not welcome. Algae grow excessively to form
‘blooms’, which when they die do a lot of harm to the organisms which
live in water. The bacteria that decompose them use a lot of oxygen to
do so and thus deprive fish and other organisms of oxygen. This affects
the
ecological
balance
of
the
lake
or
river
which
is
called
‘Eutrophication’. It is leading to an increasing number of dead zones
around the world’s water bodies, where nothing grows.
We are a group of students from St.
Margaret’s College Girls’ Secondary
School, Zejtun. We wanted to do a
science project from which eventually
some benefit to the environment of
Malta would result. This project was
chosen because nitrate pollution of
the water table is a very pressing problem locally. Water is one of the
most precious natural resources in Malta and this is being polluted by
the indiscriminate use of artificial fertilisers by farmers. Thus we hoped
that through this study, the polluting effects of different fertilisers could
be identified and this information disseminated to relevant people.
The aim of our project was to investigate the amount of nitrates leached
by three different types of fertilizers in two different types of soil. Water
soluble fertilizer, fertilizer pellets and cow manure were used because
we wanted to study a variety of natural and artificial fertilizers. Loam and
clay soils were used as these soils are quite common in Malta.
Different fertilisers were added to
each soil sample and the amount of
nitrates leached was tested. The
same amount of fertilisers and soil
were used in each case, to ensure fair
testing.
Rain water, which causes
leaching, was simulated artificially in the lab by adding two shots of
water to each fertilised soil sample. Water that seeped through each
sample was analysed for nitrates after each shot using
Precision Nitrate Test Strips. The results for each soil
and fertiliser combination were then compared.
From our experiments, we have concluded that the
fertilizers which are most harmful for the environment
are the artificial ones: pellets and water soluble powders. This is
because these two types of fertilizers leach the highest amount of
nitrates. We encourage farmers to use the pellets in exact amounts
whenever possible and to only give their crops fertilizers when needed;
otherwise the excess nitrates will be washed away by rainwater.
Excess fertilizer means wasted money and
damage to the environment. Cow manure is the
least polluting fertilizer as it leaches minerals
very gradually when microorganisms break it
down in the soil over a long period of time. We
promote farmers to use natural manure as a
fertilizer. After all it is cheap and natural, and
best for the environment
We also encourage farmers not to put a lot of fertilizer in the soil if
heavy rain is forecasted. If a substantial amount of rain falls before the
crop has had a chance to use the fertilizer supplied, the nitrates may still
be washed away.
With the implementation of the 2010 Nitrates Action programme the
nitrate concentration in the main sea level groundwater has been fairly
stable. Let’s work harder so that the decisions you make today will
affect the lives of your children and grandchildren. A healthy
environment means a healthy generation!