City authorities are trying to find out what caused the water in the Rialto Bridge area to change color. The environmental protection authority in the area is analyzing samples and the police are investigating.
The case may have ties to other events in Italy, in which environmental groups painted historic sites and even used charcoal to blacken the water at Rome's Trevi Fountain. Unlike previous cases, however, no activist group claimed responsibility for the Venice incident. Another hypothesis is that there is a connection between the color and the traditional flotilla of rowboats in Venice, the vaguely, to protest the damage caused by motorized boats.