Effect of Various Environmental and Social Diverse Locations on Heavy Metal Accumulation in Selected Medicinal Plants of Northern Region of India

This study aims to measure the heavy metal concentration in soil and frequently used medicinal plants collected from various environmental locations, while evaluating the influence of these sites on the mineral composition of the plants. Plant and soil samples of Calotropis procera, Euphorbia hirta, Achyranthes aspera, Cynodon dactylon and Argemone mexicana were collected from four different environmental locations of the northern region of India namely: Thermal power plant (TPP), Industrial area (IA), Brick kiln (BK) and Heavy traffic area (HTA). Essential metals i.e. Mn, Fe, Co, Zn and potentially toxic metals i.e. Cr, Ni, Cd, Hg and Pb were quantified in soil and plant samples using Atomic absorption spectrophotometry (AAS) and subsequently compared. The highest concentration of iron (Fe) (70.8±0.02 ppm) was found in soil from the thermal power plant area. The most toxic heavy metal lead (Pb) (8.3± 0.01ppm) and cadmium (Cd) (0.1±0.001ppm) were observed highest from Heavy traffic area sites in Calotropis procera and Euphorbia hirta respectively, although found in permissible limit of 10 and 0.3 ppm respectively set by WHO (World Health Organisation) for herbal products. The concentration of Hg remained below detection limit in all tested samples. There is a significant variation in plant location and heavy metal concentration (P≤0.05). Heavy metals were found below permissible limits in all tested samples. However, continuous consumption of some toxic metals can lead to accumulation in the body. Therefore, in order to prevent health risks, it is recommended that cultivation of medicinal plants should be prohibited near environmentally polluted site especially heavy traffic area.