Executive Summary : | Environmental pollution by heavy metals (HMs) has become a major societal issue owing to uncontrolled anthropogenic activity, besides natural causes. Entry of toxic HMs in human system mainly through contaminated water, food and air leads to a large numbers of serious health issues. Rapidly developing countries like India need to be aware of these problems and find preventive and remedial measures. Sometimes expensive high-tech remedial measures are not easy for a country like India, and hence emphasis has to be on prevention. Indigenous research towards mitigation and remediation has to be encouraged [A Position Paper, INSA, 2011]. Arsenic and other heavy metal contamination of groundwater in Assam is becoming a grave concern for recent years. According to government estimates, fluoride contamination affects 23 districts and arsenic contamination affects 24 districts out of a total 33 in the state [Business Standard Report, 2019]. Arsenic is a threat to public health across Assam, affecting over 1.6 million people according to the Ministry of Jal Shakti [news report 2021]. A high percentage of iron contamination (77%) in tubewell waters of this region indicates the severity of the HM pollution [Chakrabarty et. al., 2011]. Different regions of the state have been witnessing elevated and above safety limit of HMs Cd, Mn, Al, Pb, Fe, As in drinking water [Borah et al. (2009a,2009b), Buragohain et al. (2010)]. Testing of water quality on a regular basis and determining the heavy metal contaminations, therefore, is a very relevant societal necessity. Pholuminescence (PL) is an extremely sensitive phenomenon and can probe elements of very low concentration, upto the trace level. Flavonoids are a category of naturally occurring organic compounds found in fruits, vegetables, grains, barks and roots. Flavonoids, as a group, include more than 8000 different identified compounds, and are responsible for a number of functions within plants, such as the coloration of the different parts of fruits or vegetables (leaves, flower, peel) [D. Skarpalezos et. al. 2019]. Flavonol, a type of Flavonoid is a fluorescent pigment with enough potential for fluorescence sensing due to its aggregation-induced emission enhancement (AIEE) and excited state intramolecular proton transfer (ESIPT) properties. In this project, the optical properties (absorption, PL peak intensity, yield, excited state lifetime etc.) of Flavonol will be harnessed for sensing the HMs in water. Flavonol will be extracted from different parts of locally available plants. Sensing will be studied in aqueous as well as thin film media. Successful completion of the project will lead to the development of environment friendly, low cost, Flavonol based optical sensors for the detection of toxic HMs found in the groundwater of Assam. The project will contribute towards the 2030 Agenda for Sustainable Development, adopted by all United Nations Member States in 2015. |