The neon green water that mysteriously leaked into Venice’s Grand Canal over the weekend was caused by fluorescein – a chemical used to detect underwater structural leaks, CNN reported Tuesday.
But the culprit behind the dye remains a mystery. The Venice Regional Environment Agency said the staining was likely intentional because the amount was too large to be an accidental spill, according to the news network.
Officials are pursuing multiple leads, including the possibility of environmental activism, Venice police told CNN.
The phosphorescent green was noticed spreading near the arched Rialto Bridge on Sunday, according to at the Associated Press. Luca Zaia, the governor of the Veneto region, sparked curiosity by posting a photo of the water after it was reported by locals, the news service wrote.
NPR rated that the contamination suspiciously coincided with an annual rowing race which “aims to celebrate the environment of the Venetian lagoon as well as to protest against the movement of the waves due to the excessive traffic of motorboats which annoys the city” .
The channel has been tinted in the past to make a statement.
In 1968, eco-artist Nicolas Garcia Uriburu used fluorescein to green the Grand Canal to “promote environmental awareness,” NPR wrote.