4.4 Bioremediation Methods
51
Table 4.1
Some examples of azo dyes and their toxic effects.
Sl. no.
Dye
Toxic effects
1.
Disperse red 13
It demonstrates mutagenic potential in human
lymphocytes by causing chromosomal damage
2.
Tartrazine
Oxidative stress can be caused by free radicals
forming
3.
Benzidine
Carcinogenic
4.
Pigment red 3
Weakly mutagenic
5.
Acid violet 7
It has got potential to cause chromosomal
aberrations, lipid peroxidation, and inhibitory
effects of acetylcholinesterase
6.
1-amino-naphthalene
Carcinogen
7.
p-dimethylaminobenzene
Cytotoxic and genotoxic effects on the bone
marrow cells and rat spermatozoids
8.
Disperse red 1 and
disperse orange 1
Increase the micronucleus level in human
lymphocytes and HepG2 Cells
9.
Scarlet RR
Cytotoxic and mutagenic effects in time- and
dose-dependent manners showed in Allium
cepa root tip cells
10.
Malachite green
Genotoxic and carcinogenic and also affects
immune and reproductive system
11.
CI disperse blue
Base pair substitution and frame-shift
mutation in Salmonella
Source: Saini et al. [3].
spleen, and liver in laboratory animals and are also known to cause chromosomal
abnormalities in mammalian cells. Some azo dyes can also induce the formation
of liver nodules in experimental animals. Table 4.1 summarizes the different toxic
effects of the azo dyes [3].
4.4
Bioremediation Methods
4.4.1
Types of Approaches: Ex situ and In situ
Bioremediation methods are mainly divided into in situ and ex situ. The ex situ
method refers to the treatment that involves the physical excavation of pollutants
from polluted sites and then transporting them to another site for treatment, while
the in situ technology involves the removal of pollutants at the site of pollution. The
information of in situ and ex situ bioremediation is as follows:
i. Land-dwelling: This method can use solid-phase treatment solutions for con-
taminated soil.
ii. Bioreactors: The biodegradation in a large reactor can be used to treat liquid or
slurry.