1. School of Environmental Sciences, Inter University Instrumentation Centre, Mahatma Gandhi University, Kottayam 686560, Kerala, India
2. School of Environmental Studies, Cochin University of Science and Technology, Kochi 682022, Kerala, India
3. Environmental Monitoring and Assessment Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400094, India
4. Inter University Instrumentation Centre, Mahatma Gandhi University, Kottayam 686560, Kerala, India