Presence of heavy metals in medicinal weed species grown at contaminated sites

摘要

Concentration of heavy metals like Cd, Pb, Ni, Co, Zn, Mn and Fe were tested in medicinal weeds growing at heavy metal contaminated site around Jabalpur during winter season of 2008. Except Vicia sativa, higher concentration of Cd was observed in weeds like Sonchus arvensis (3.07 mu g/g), Alternanthera viridis (1.56 mu g/g), Anagalis arvensis (1.5 mu g/g), Melilotus indica (1.30 nu g/g), Eclipta alba(1.14 mu g/g), Chenopodium album (1.15 mu g/g), Cichorium intybus (1.05 mu g/g), Lathyrus sativa (0.77mu g/g). Copper concentrations in plant was higher than prescribed standard limit, viz. Amaranthus viridis (46 mu g/g), Ageratum conyzoides (22 ug/g), Polygonum persicaria (37 mu g/g), Commelina communis (30 mu g/g), Alternanthera sessilis (22 mu g/g),Solanum nigrum (22 mu g/g) and Ipomoea aquatica (21 mu g/g). Ni and Zn contents exceeded the permissible limit in shoots of Polygonum persicaria (19,265 mu g/g), Commelina communis (17,192 mu g/g), Alternanthera sessilis (14,216 mu g/g), Amaranthus viridis (17,488 mu g/g), Ipomoea aquatic (15,238 mu g/g), Heliotropicum indicum (16,89 mu g/g), Ageratum conyzoides (15,127 mu g/g), Blumea lacera (3,218 mu g/g), Solanum nigrum (16, 191 mu g/g), Convolvulus arvensis ( 15,125 mu g/g) and Cyperus iria (15,177mu g/g) respectively. Calotropisprocera (21 mu g/g) exhibited higher Pb concentration exceeding prescribed standard limit. Conversely, Co content was found within prescribed limit in Melilotus indica, Lathyrus sativa, Heliotropicum indicum, Cyperus iria,Convolvulus arvensis, Blumea lacera, Pb below standard limit in Hyptis suaveolens, Cichorium intybus, Lantana camara and Datura stramonium, and no Pb was detected in Alternanthera sessilis, Abutilon indicum, Xanthium strumarium, Anagalis arvensis.