Abstract:
Appropriate effluent treatment processes are expected to significantly reduce the toxicity of effluents before they are released to the
natural environment. 0e present study was aimed to assess the spatial and temporal variations of the physical and chemical water
quality parameters of a natural water body receiving treated textile effluents and to assess the chromosomal abnormalities induced
by the treated textile effluents. Four sampling sites (A: effluent discharge point; B: 100m downstream from site A along the
tributary; C: 200m downstream from site A along the tributary; D: 100m upstream from site A along the tributary) were selected
associated to a tributary that received treated textile effluent. 0e physical and chemical water quality parameters were measured
in the composite water samples collected from the study sites, and Allium cepa bioassay was conducted using aged tap water as the
control. Sampling was conducted in both rainy and dry seasons. 0e conductivity, TDS, COD, and colour intensity of the water
samples collected from the study sites were significantly higher during the dry season compared to those in the rainy season.
Allium cepa root meristematic cells exposed to water samples from sites A, B, and C showed a significantly high interphase and
prophase indices compared to those exposed to aged tap water and upstream site during both rainy and dry seasons. 0e mitotic
index of the root tip cells of Allium cepa bulbs exposed to the water samples collected from the effluent discharge point (site A) and
from the 100m downstream site from site A (site B) was significantly lower than that of the other sites in both rainy and dry
seasons. However, the mitotic index of the root tip cells of Allium cepa bulbs exposed to the water samples from the upstream site
was not significantly different from that of the control treatment during both sampling seasons. 0e bioassay indicated that the
mitotic index and phase index of the root meristematic cells of Allium cepa can be affected by the treated textile effluents released
to the water body and the occurrence of C metaphase, chromosomal adherence, bridges, disturbed anaphase, vagrant chromosomes,
and chromosomal breaks indicated that the treated textile effluent receiving tributary can possibly contain genotoxic
and mutagenic compounds which can induce chromosomal abnormalities.