In the industrial world there is growing evidence of ground water contamination.
Environmentally relevant bio-tests provide information on initial levels of
damage and disasters and assist in developing precautionary measures and
strategies for the environment. Plant toxicity tests are not only quick and
inexpensive relative to the more sophisticated chemical analyses, but also require
less maintenance than other tests which use organisms.
In this research, garden cress seeds (Lepidium sativum L) were exposed to
different phenoxyalkanoic acid herbicides 2,4-D(2,4-dicholorophenoxy) acetic
acid), 2,4-DP((RS)-2,(2,4-dichlorophenoxy) propionic acid), 2,4-DB (4-(2,4-
dichlorophenoxy)butyric acid), 2,4,5-T (2,4,5-trichlorophenoxy)acetic acid), and
MCPA (4-chloro-2-methylphenoxy) acetic acid) in a phosphate contaminated
media for 120 h in order to determine the effect of toxicity to root growth. Each
trial was duplicated for consistency of the experimental results (significance is
taken as p < 0.01).
As an analytical approach IC50 (50% inhibitory concentration) values of the
substances were found from the graphical expressions of root length inhibitions.
For the determination of the IC50 values, a non-linear regression model was
applied using the least square method. The calculated IC50 values clearly
represent the toxicity of the herbicides.
Keywords: aqueous media, garden cress seed (Lepidium sativum L.), herbicide
toxicity, phosphate contamination, IC50.