Pentachlorophenol (PCP) is known to be a very effective biocide, used very
widely a few years ago. Eventually its use was stopped in many countries wh
en it was shown that PCP is highly toxic, especially to water organisms, an
d to some land animals and plants. However, PCP is still present in the env
ironment, mostly as a metabolic product of some pesticides. Roots of shallo
t (Allium ascalonicum auct.) were exposed to different concentrations of PC
P: 0.001, 0.01, 0.1 and 1 mg/dm(3) for 24 h. The tested solutions were adju
sted to pH 3.0, 6.0 or 8.0. Root tip cells were analyzed either after 24 h
of treatment or after treatment and 48 h recovery in water. Genotoxic effec
ts of PCP in root tip cells were noted, the extent of which depended on the
PCP concentration and pH. Chromosome and mitotic aberrations were found, i
ncluding the significant occurrence of micronuclei, chromosome bridges and
multipolar cells.