Mangroves spread over two kilometres along the Thane creek near the Vikhroli-Kanjurmarg border are dying because of unknown reasons, a non-government organisation (NGO) has claimed.
A complaint filed on June 19 by the NGO Vanashakti with the state forest and environment says: "Tall Avicennia marine trees (mangroves) as well as smaller ones are found completely dead and many are on the verge of dying. Initially, we thought it could be because of the attack of the moth Hyblaea puera. But on close examination, it doesn't appear so. The leaves are all intact, but have turned completely brown and the trees are dying."
The complaint adds, "The condition is restricted to Avicennia Marina species (of mangroves) as of now. This is the dominant species, and also it has been the most resilient and tolerant of all mangrove species found in the Thane creek."
State environment secretary Valsa Nair Singh said she would direct the Collector's office in Thane to probe the issue.
When HT visited the location last week, it found that a nullah near Kanjurmarg was disposing sewage and solid waste into the creek. Plastic bags and bottles, shoes, thermocol and even wooden furniture were lying amid the mangroves.
"I have seen pictures of the plants mentioned in the complaint and prima facie, it does not look like an insect attack," said N Vasudevan, chief conservator of forests and head of mangrove cell. "If Avicennia Marina is indeed dying, then highly toxic effluents might be the reason," he added.
At least three storm water drains flow into the Thane creek near the eastern express highway. According to civic officials, waste water is not treated before being released in the creek. "These drains are only meant for storm water management and not waste water. It is not in our purview to keep a check on waste water released into the nullah from slums or local factories," said Laxman Vatkar, chief engineer, storm water drainage department, BMC.