NEERI finds way to tackle microbes’ menace on rocks of heritage sites

By Vikas Vaidya :

Heritage sites are facing problems of green vegetation microbes. Insects may settle on stones rock cuttings if they find appropriate temperature, their colonies grow and they stay there. This results in acidic reactions, ultimately forming coloured patches, mostly black, on the rocks. This has become the headache for the authority. How to deal and curb the menace was the million dollar question. Finally the work of finding solution was given to National Environmental and Engineering Research Institute (NEERI). The decision of Archeological Survey of India to bestow the work upon NEERI has proved right by NEERI as it has come up with the proper solution.

The four scientists from NEERI including Dr Piyush Kokate, Dr Asifa Qureshi, Dr Shalini Ghyani, Dr Krishna Khairnar and their team started working on the project. They selected Ajanta Caves, Chhatrapati Shivaji Terminus to begin with and they noticed insects surviving in stone masonry creating health issues too. It is a heritage mission mode. The work involves conservation and restoration of heritage structures. Insects breeding has become rampant there which harms the structure. Dr Asifa Qureshi said, “Any living thing touch the monument it affects. In case of Ajanta Caves, we are studying only outer surface, the rocks on it are getting deteriorated. Deteriorates means bacteria and microbes are degrading the surface. They secrete some acid that reacts on the surface.

This chemical reaction is leading to salt deposition, acidic case, bioweathering. All these changes are taking place because of environmental changes.” Changes in colour of the rocks was not that faster earlier. In recent times, chopping of trees that was helping in preventing pollution has large impact on environment. The industrial pollution too has added to the woes of these structures. The outer surface of these structures are becoming black. Dr Piyush Kokate who is looking after the lighting side said, “We are studying what solution can be applied, also the behaviour of insects.

The solution that we are trying to find should be eco-friendly.” Dr Shalini Ghyani is looking after the bidiversity around the monuments. Dr Piyush Kokate is dealing with lighting devices, Dr Asifa Qureshi is tackling the growth of bacteria, trying to find natural remedy. Dr Krishna Khairnar is working on finding bacteria that would remove the nitrates, sulphates on the rocks. Dr Khairnar said, “The research on finding bacteria that can reduce the Nitrates, sulphates. We are treating such rocks by putting bacteria on it.” NEERI has prepared the report and it would soon submit the same with all solutions, recommendations.