Green water a mystery but not considered harmful

3-on-3 tournament open to all area kids as part of three-day Biddy weekend
July 28, 2016
Arlen “Benny” Cenac and family christen, launch new tow vessel
July 29, 2016
3-on-3 tournament open to all area kids as part of three-day Biddy weekend
July 28, 2016
Arlen “Benny” Cenac and family christen, launch new tow vessel
July 29, 2016

Terrebonne Parish and state officials are trying to determine how a dye that is used to detect leaks in offshore oil and gas operations and for medical purposes turned water in Houma gutters green from Hollywood Road to Barrow Street Friday afternoon.

The specific substance and its source have not been officially confirmed, but is believed to be flouroscein, a fluorescent dye that does not harm marine life and which, once turned green through its contact with water, is not considered a health threat. Prior to its contact with water the substance, initially a powder, is reddish-brown. The green sheen was thought from visual observations as antifreeze. But the volume and breadth of its appearance caused Terrebonne Office of Homeland Security and Emergency Preparedness Director Earl Eues to take a closer look.


The Louisiana Department of Environmental Quality is also investigating.

Ingestion of concentrated amounts, most likely when in powder form, can cause illness and, in unusual cases, death. But its current state of dilution – which makes it become green – eliminates health concerns, Eues said. Fluoroscien is annually used to turn the Chicago River green for St. Patrick’s Day. It has also been used to signal rescue sites at sea.

Its presence in Bayou Terrebonne because of travel through storm drains may turn parts of the water body green as well.


Another green mystery, present in the waters of the Pointe-aux-Chenes, was determined to be a form of algae. Some residents in that area reported dead fish, which emergency and wildlife officials said was normal with such a situation.

Eues said the algae blooms tend to form in summer, when temperatures are high. Runoff from lawns adds nutrients to water bodies, favoring the algae growth. When the algae consume available oxygen in the water fish dies as well.

Louisiana Department of Wildlife and Fisheries spokesman Rene LeBreton said state biologists surveyed the area Monday and found “very few dead fish.”


Some dead fish already present may have been scavenged by wildlife or sunk and ended up scavenged by crabs, LeBreton said.

“They did find a very strong algal bloom in the area,” LeBreton said. “That bloom would have produced very low dissolved oxygen in the early morning, which is probably the cause of the reported mortality.”

In Paris earlier this year rivers turned green due to a similar substance that interacted with rainwater and the bayou in Houma. Media reports stated that environmental advocates had purposely introduced the dye into the rivers to draw attention to their pollution concerns.


No harm to the ecosystem or people was reported.

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