Waste incinerator ash from Manali is loaded with toxic heavy metals

CHENNAI: Sparking environmental and health concerns, the Tamil Nadu Pollution Control Board (TNPCB) has confirmed high levels of toxic heavy metals in the bottom ash of the Greater Chennai Corporations 10-tonne-per-day municipal waste incinerator at Manali, revealing contamination levels as high as 360 times the permissible limit. In its report to the southern bench of National Green Tribunal (NGT), the TNPCB said the incinerators bottom ash contained heavy metals in concentrations exceeding the prescribed limits under Schedule II of the Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016. The analysis was conducted at the boards Advanced Environmental Laboratory (AEL), Chennai, in April 2025. The data show that cadmium levels were in the range of 291.6 to 364.5 mg/kg, which is 364 times the prescribed limit of 1 mg/kg. Similarly, chromium, lead, copper, zinc, and mercury were all in excess quantities by several times. This corroborates the findings from a civil society fact-finding report released in April this year. That report titled Waste Incineration: Zero Pollution or Zero Truth? had found cadmium at 19.22 mg/kg (24 times above WHO soil standards), lead at 101.8 mg/kg (1.2 times), and chromium at 116.63 mg/kg (1.2 times) in soil near the ash disposal site. By comparison, activists say the TNPCBs internal ash data show cadmium levels over 365 times the permissible limit, making it one of the most severe cases of industrial contamination in Chennai. The TNPCBs own analysis confirms what we have been saying for years this incinerator is poisoning people and the environment, said Dr Vishvaja Sambath of the Chennai Climate Action Group (CCAG). The community has reported respiratory illnesses and black soot deposition at homes. Now theres official proof of toxic ash leaching into the ecosystem. The TNPCB report also exposes severe operational failures. Inspections on April 2 and May 14 found the unit non-operational, its venturi and wet scrubbers in dilapidated condition, and about 500 kg of ash stored openly on the premises. The board has ordered GCC not to restart plant operations, which was shut down in April, until it revamps its pollution control systems and obtains a renewed consent to operate.However, civil society groups accuse the GCC of misleading the tribunal. In its June reply, the corporation had claimed fly ash is converted into pavement blocks and ETP sludge into organic manure. This is blatant lie said Jaiganesh of Kodungaiyur Thozhargal. TNPCB confirmed the ash is toxic and is being dumped in Kodungaiyur, contaminating groundwater. How can the government now justify pushing for two waste-to-energy projects that will burn 3,600 tonnes of waste daily? With the TN governments 2025 budget allocating `3,450 crore for new incinerators in Kodungaiyur (2,100 TPD) and Tambaram (1,500 TPD), campaigners warn Manali findings must serve as a wake-up call. This is not waste management, its mismanagement on a deadly scale, said Sambath.