MAP Technical Reports Series No. 106 UNEP

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This environmental disturbance of unprecedented dimensions not only caused serious
problems for the municipal authorities responsible for public health and keeping the beaches
clean, but also had a severe psychological impact on the mass-media and those making their
living from tourism (Goldoni, 1976).
The press, misled by the many illogical comments flying around, carried gloomy
warnings of disaster, often blaming the fish kill on dangerous pollutants or highly toxic
microalgae.
The Emilia-Romagna region was able to draw on all the research performed by the
University of Bologna from 1966 to 1975 on heavy metals (Hg, Cd, Pb) and chlorinated
hydrocarbons (DDT, PCB) contents in the tissues of molluscs and fish in the North Adriatic
(Viviani, 1977b; 1988; 1989), which demonstrated levels incapable of inducing acute toxicity or
causing mortality, as well as the initial results indicating the absence of algae toxic to fish.
Thanks to this information, the authorities were able to rule out the existence of "dangerous
pollutants" and fish toxins in the North West Adriatic.
These data directed public opinion towards the new concept of eutrophication,
"coloured tides" and the consequent oxygen deficiencies.
After detailed investigations, the doubts disappeared and the true cause of the disaster
was identified: the death of the benthic fauna was related to the oxygen shortage in the bottom
waters due to the sedimentation of the phytoplankton biomass during mineralization (Turci, 1976;
Viviani, 1977a).
How did tourism respond to these events? An analysis of tourist numbers does not
seem to show any reduction in bummers as a consequence to the problem of "coloured tides"
due to eutrophication. No one can deny that the availability of precise information has helped to
shed light on the real causes of the phenomenon and the negligible level of the health risks
involved.
The response of tourism to the problem of mucilages has been different. It should be
remembered that this phenomenon has occurred in an invasive form in 1988, 1989 and 1991
(see chapter 5.2.5).
During July and August of these years, widespread masses of mucilaginous material
tended to approach the coast, and in some cases the beach. Apart from the "dramatic" nature
of the phenomenon and the large area affected (10,000 km 2 in summer 1989), long stretches
of coastal water were unsuitable for bathing. This triggered social tensions and negative
psychological effects, deriving mainly from the uncertainty over the future of the area's tourist
industry. These worries were partly worsened by the lack of clear answers regarding the causes
and mechanisms of formation of the phenomenon.
Although tourist numbers had consolidated during the previous years, in spite of a
considerable loss of water quality because of the current algae blooms, the mucilages caused
significant drops in visitor figures in 1989 and 1990 (Agertur, 1992) (see Fig. 18).