Research needed on whether fly ash disposal in mine voids leads to contamination of groundwater with heavy metals, says expert committee
New Delhi: An expert panel of the Union environment ministry has called for at least a 10-year-long study on whether fly ash disposal in mine voids leads to contamination of groundwater with heavy metals.
The suggestion was made by the Expert Appraisal Committee (EAC) for thermal power and coal mining projects at its meeting on 29 February. The committee said the extensive research can be supported by funds provided by corporates that generate power and produce coal.
The expert panel requested the environment ministry to take necessary action to launch the programme under environment research division.
Fly ash is produced from the coal combustion process. It is usually used to fill mine voids. But in the past few years concerns have been raised over its environmental impact from several quarters.
The National Green Tribunal, too, while hearing a case in 2015, asked India’s nodal pollution watchdog, the Central Pollution Control Board (CPCB), to form a committee to check if fly ash disposal in mine voids is leading to environmental degradation or damage in areas of Angul and Talcher in Odisha.
The CPCB committee had noted no significant higher concentration of heavy metals in groundwater due to filing of mine voids by fly ash. It had, however, called in for comprehensive monitoring of groundwater quality surrounding the ash disposal sites.
Meanwhile, noting that fly ash disposal in mine voids is not environmentally safe, the environment ministry’s expert panel said that, “the interface between the water and fly ash at the bottom of fly ash filled void results in leaching of heavy metals into groundwater system as evident by high levels of trace elements particularly heavy metals in ground water samples collected from sites located close to the ash filled voids".
It also expressed concern over reduction in recharging of groundwater due to fly ash filled mine voids. The expert panel also noted that ash-filled voids cannot support tree species because of poor root system development which in turn results in uprooting of trees even by low velocity winds.
Experts, who have been working on groundwater issues, said EAC’s move is good but nothing can happen until environment ministry strictly ensures compliance of environmental safeguards while giving environmental clearances.
“Long term research is needed but EAC also must ensure a mechanism to achieve compliance of conditions it specifies while giving environmental clearances," said Himanshu Thakkar, an environmental activist working on water-related issues.
Millions of tonnes of fly ash is generated every year in India, prompting the environment ministry in 1999, 2003 and 2009 to issue directions for its proper use and disposal.
According to a recent study by the Centre for Science and Environment (CSE), an NGO working on environmental issues, fly ash disposal remains a major problem with only about 50-60% of the total fly ash generated by the power sector being utilised. Around 173 million tonnes of fly ash was produced across India in 2013-14.
The remaining is dumped into poorly designed and maintained ash ponds. As per estimates, about a billion tonnes of this toxic ash lie dumped in these ponds, polluting land, air and water. By 2021-22, the thermal power sector is estimated to produce 300 million tonnes of fly ash a year and with that, utilisation of all the fly ash being generated is going to become even tougher.