Polluted soils, also designated as contaminated soil, is defined as the presence of man-made toxic substances in soil. Heavy metal contamination is one of the major abiotic stresses and a global due its characteristic toxicity and environmental persistence. It is threatening sustainable agricultural production and health of millions of people. Contamination of soil by heavy metals occurs naturally and through anthropogenic activities. Heavy metal concentration beyond a certain limit degrades the soil, the quality of the produce and ultimately the human and animal health. Some of the major sources of heavy metals are mining and landfill, city waste, factory effluents etc.

The toxic metals accumulated in the bodies of living organisms can be tetratomic, mutagenic and endocrine disrupters. The potent heavy metal pollutants are chromium, cadmium, lead, mercury, nickel, selenium etc. reactive oxygen is produced due to heavy metal stress in living being resulting in oxidative damage and health related adverse effect. Heavy metals are the natural components of earth crust and cannot be degraded. Several physical, biological and chemical methods are commonly used for decontamination of metals. Phytoremediation is presumably the best technique for remediating heavy metal toxicity; it is safe, ecofriendly green technology. Our group at CSIR-CIMAP, India conducted field and greenhouse studies using essential oil bearing hyperaccumulating plants. Such plants are used for higher uptake of metals from the polluted soils without affecting the plant metabolism and products. Plant through several biophysical and biochemical processes viz. adsorption, transport, translocation and hyperaccumulation remediate heavy metals from the soil. Such plants must have specific adaptation properties to survive under toxic metals and metalloids and they must be metallophytes. Some hyperaccumulating food crops are often used for phytoremediation viz. Helianthus annus, Brassica napus, Zea maize etc. The problems of such crops is that the metal accumulated could be channelized to human and animal being and are not safe. The aromatic crops viz. vetiver ( Chrysopogon zizanioides), Lemongrass ( Cymbopogon flexusosus), Palmarosa ( Cymbopogon martini) could be safely used for phytoremediation. Such proposition fulfils two-pronged advantages viz. hyperaccumulation and production of essential oil from the fresh herbs by hydro-distillation. Such crops are tolerant to toxic metals, fast growing, produce high biomass, have extensive root system and accumulate high amount of metals.

Such green technology represents a secure and feasible approach for remediating pollutants and offering biological economic benefits through production of high value essential oil with minimum inputs, least risks and maintenance.

Keywards: Aromatic crops, soil pollution, heavy metals, phytoremediation, Contamination

Prof Dharani Dhar Patra, presently working as the Director of School of Agricultural sciences, Seacom Skills University, Bolpur,West Bengal, India (2020-2023), has been the Vice Chancellor of Bidhan Chandra Krishi Viswa Vidyalaya, Kolkata, India (2016-2020) and Professor-cum-Chief Scientist (Natural Resource Management) at CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India ( Under Ministry of Science and Technology, Government of India, New Delhi, India (1987-2015). Prof Patra did his Graduation and post-Graduation from from BCKV, India and did his PhD from Indian Agricultural Research Institute, New Delhi, India (1978-1982) and then went to Rothamsted, UK for post-doctoral research and subsequently joined Rajasthan Agricultural University, as an Assistant Professor in Natural Resource Management (1982-1987).