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“Why
do all fish become female?This is the question I asked myself
when I was looking into the management of rises in water levels,
especially in the Loire. I examined the variations in water temperature
in French rivers and their impact on fish and other aquatic species.
The physicochemical quality of our water has a considerable influence
on fish, and I wondered what effect it might have on man. Water
quality deteriorates with time; recently, the presence of medicines
- namely hormonal molecules such as oestrogen and progesterone
linked to traces left by contraceptive pills in urine. Found
in our river water, these hormone residues have the unfortunate
effect of making all fish female, which means their reproduction
is greatly disrupted.
All
the dirty water we flush into our sewers is collected
and treated in purification plants. Reintroducing this into the
water cycle – into natural waters – means that we have
to submit them to numerous treatments to eliminate all waste
pesticides, medicines and other pollutants; industrial, agricultural
or domestic such as detergents.
Eliminating medicines present in wastewater is a new and particularly
complex problem. As they are present in an infinitesimal dose,
they are difficult to filter out or eliminate with otherwise
usually successful treatments. Therefore it is important to pursue
the development of new processes in order to effectively purify
water. This is the subject of the thesis that I began upon leaving
my engineering school, where I specialised in water and waste
treatment.” |