Polluted tidal inflows threaten flamingo lake

Navi Mumbai: Fresh scientific tests have raised serious concerns over the deteriorating health of DPS Flamingo Lake at Nerul in Navi Mumbai with polluted creek water entering the wetland during high tides emerging as a major threat to the fragile ecosystem that forms part of the Ramsar-listed Thane Creek Flamingo Sanctuary (TCFS).

The latest laboratory analysis of water collected from the tidal inflow channel has revealed contamination levels far exceeding permissible standards, adding to fears that worsening water quality may be contributing to the sharp decline in flamingo sightings at the wetland this season.

According to the test results, the inflowing water recorded Total Dissolved Solids (TDS) of 19,600 mg/l, more than nine times the permissible limit of 2,100 mg/l prescribed under IS 2490:1974 standards for inland surface waters. The sample failed to meet the required water quality norms.

The test was commissioned by environmental activist Sandeep Sareen of the Navi Mumbai Environment Preservation Society and NatConnect Foundation director B N Kumar.

The findings come amid growing global concern over the degradation of wetlands. The UNEP-DHI Centre for Water and Environment, in its report Wetlands: The Unsung Heroes of the Planet, has warned that wetland loss has accelerated since 2000 due to pollution, habitat degradation and unsustainable human activities, resulting in steep declines in species dependent on these ecosystems.

Experts note that flamingos are particularly vulnerable to changes in water quality because they rely on a delicate balance of salinity and water chemistry that supports algae, diatoms and microscopic invertebrates—the primary components of their diet.

The latest results also reinforce concerns raised by earlier studies commissioned by NatConnect Foundation. A water sample collected from DPS Flamingo Lake in March recorded an alarming TDS level of 21,720 mg/l. Another sample collected in April from a drain discharging into the wetland showed TDS levels of 7,950 mg/l. The April analysis also revealed a Biochemical Oxygen Demand (BOD) of 36.4 mg/l, significantly exceeding permissible limits. All three samples failed to conform to prescribed inland water quality standards.

Environmentalists warn that the cumulative impact of polluted tidal inflows and the spread of extensive blue-green algal mats could have serious ecological consequences for the wetland.

“Flamingos can tolerate natural salinity, but they cannot thrive in waters carrying a cocktail of sewage, urban runoff and other contaminants. The deteriorating water quality is steadily eroding the lake’s ecological balance and shrinking its food base,” Sareen said.

Kumar stressed the need for urgent conservation measures. “The continuing pollution underscores the urgent need to expedite the final Government Resolution granting Conservation Reserve status to DPS Flamingo Lake and ensure stronger legal protection,” he added.