Environmental risk assessment (ERA) of terrestrial environments
polluted by heavy metals in Peru requires standardized biological
organisms, the use of which is simple, practical, sensitive and
repeatable, such as seeds of higher plants used in eco-toxicological
bioassays. The aim of this research was to evaluate the phytotoxic
effects of Cr6+, Hg2+ and Pb2+ as potassium dichromate (K2Cr207),
mercury chloride (Cl2Hg) and lead acetate ((CH3C00)2Pb), respectively,
on growing roots of four species of higher terrestrial plants: onions
(Allium cepa L., Liliaceae), red beets (Beta vulgaris
L., Chenopodiaceae), rice (Oriza sativa L., Poaceae) and
radishes (Raphanus sativus L., Brassicaceae) at 192 h (8 days)
exposure. Bioassays of static sub-lethal toxicity for each metal and
for each species of plant were performed, using a randomized complete
block design: six concentrations and eight replicates with 240 seeds
for each bioassay. The sequence in ascending order for mean inhibition
concentration (IC50 in mg L-1) on root growth at 192 h exposure in the
majority of cases was: Hg2+ > Cr6+> Pb2+. The perspectives of use
for evaluation of soils contaminated by heavy metals in Peru are
analyzed