For decades, the Kukatpally inlet has been bringing effluents from industrial estates into the Hussainsagar lake, blatantly violating norms, ignoring the concerns of citizens and despite repeated cautioning by environmentalists.
That the lake, which once provided drinking water to the city, is heavily polluted is a well known fact. Even more alarmingly, at the confluence of the Kukatpally inlet, the levels of hazardous cadmium has reached all-time high levels.
Of the 30 sediment samples collected and analysed from the mouth of Kukatpally nala or the storm water drain at the lake, 18 were found to contain cadmium levels higher than the acceptable limits, causing an adverse impact on flora and fauna.
While the prescribed standard for concentration of cadmium as per Schedule-II of Hazardous Waste Management and Handling Rules 2003 is 50 milligram per kg (mg/kg), 13 of the samples presented more than double, and some had cadmium presence to the tune of 213 mg/kg and 276 mg/kg!
Since this sediment falls in the hazardous category, the Hyderabad Metropolitan Development Authority (HMDA), which has taken up the task of cleaning the Hussainsagar lake, will dredge the sediments at the Kukatpally nala confluence point separately. The dredging of three other inlets – Balkapur, Banjara and Picket Nalas – has commenced, and the work on Kukatpally nala has been proposed separately.
The HMDA has invited bidders for treatment and disposal of hazardous dredged sediments, and the urban planning body has decided on dredging sediments in a radius of 500 metres at the Kukatpally nala confluence point.
An estimated quantity of 4.50 lakh tonnes sediment is expected to be scooped and disposed off at a treatment, storage and disposal facility (TSDF).
The exercise looks at engaging agencies with required expertise to dredge, dry the sediment at temporary dumpsite on the shoreline and transporting the hazardous semi-dried material to the designated TSDF. “The whole exercise will be done under the monitoring of the Andhra Pradesh Pollution Control Board (APPCB) and according to specified norms,” an official said.