Tourism is one of the greater pollutants of the Mediterranean Sea

Mediterranean Sea Pollution and Tourism

Tourism is one of the greater pollutants of the Mediterranean Sea and according to League for the Environment study; tourism increases 6 to 10 percent annually.  By the end of the century the number of tourists could increase to 280 million per year.  UNEP (the United Nations Environment Programme) notes that the greatest dangers of pollution are provoked by the presence of substances such as "mercury and arsenic, from eutrophication (or the excessive disposal of nutritious substances which originate from agricultural, industrial and urban wastes), and also from the bacterial diseases produced by the microorganisms which are dumped in the sea." 

Italy's pollutants

     In the last thirty years Italy has seen approximately 50 percent of its coasts over-built (referred to as "Californication" of the shore) and overrun by stores, resorts, summer homes and other structures geared towards the promotion of tourism.  As a result, thousands of miles of sewage and other urban wastes are dumped into the sea directly without any sort of control system.  Furthermore, despite of the large sums of money that were spent on sewage treatment plants, very few systems actually work, for example, "of 300 sewage treatment plants that were built in Sicily only 5 or 6 actually worked."  
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http://www1.american.edu/TED/MEDIT.HTM