Lake Garda’s Water Quality Concerns: Sewage Discharges and Toxic Algae

One and a half years ago, the beaches of Peschiera, Sirmione, and Desenzano were flooded with aquatic plants, improperly called algae.

In July of this year, a strange fish die-off occurred in the Lower Lake, and immediately afterward, nine swans died in Peschiera. These alarming events still lack known causes; identifying them will take years, as environmental studies are very lengthy.

These incidents raised concerns about the health of Lake Garda, especially after last summer when five beaches in Peschiera were closed (two from June 3 to June 18, one from August 21 to September 13, one at the end of July, and another on August 21), as well as two in Lazise. Both locations were closed in late August, with one reopening on September 15 and the other a few days later.

Presence of bacteria and fears regarding water quality

The beaches were closed off due to the presence of total coliforms and fecal bacteria in the water, potentially pathogenic bacteria found in sewage discharges.

Biologist Giorgio Franzini, head of the Lake Garda office of Arpav (Regional Agency for Environmental Protection), Verona department, is addressing the issue.

“Many believe,” says Franzini, “that the lake suffers from industrial pollution, but the reality is different. The real problem is the presence of sewage discharges, which have worsened water quality, increasing algae production and, consequently, the possible presence of toxic algae such as Anabaena lemmermannii and Microcystis.

The toxins they produce cause gastrointestinal problems in those who ingest them. However, it should be emphasized that a massive presence of algae in the lake is necessary to cause pain, and drinking a simple sip of water is not enough to do so.”