Comparative biomonitoring of leachates from hazardous solid waste of two industries using Allium test.

Hazardous industrial wastes are inevitable source of environmental pollution. Leachates from these wastes might contaminate the origins of potable water and affect human health. The study was carried out to determine the possible genotoxic effects of leachates from solid waste of a metal and dye industry using the Allium cepa chromosome aberrations assay. The 10% leachates were prepared from solid wastes obtained from both the industries and examined for the presence of heavy metal content and genotoxicity. To simulate the field and laboratory conditions, A. cepa bulbs were exposed through soil and aqueous medium for 48 h to 2.5-10% leachates. The results revealed that both metal waste leachate (MWL) and dye waste leachate (DWL) contained high concentrations of chromium, nickel and iron that significantly induced cytogenetic alterations. Significant inhibition of mitotic index (MI), inductions of chromosomal/mitotic aberrations (CA/MA) and micronuclei (MN) formation were found in all experimental groups exposed to MWL and DWL. The effects observed were concentration dependent and the frequency of aberrations was higher with treatment of MWL than DWL. The MI was severely inhibited at 10% aqueous exposure it was 4.59+/-0.69 (P<0.001) in MWL and almost half to that induced by DWL that was 8.62+/-0.69 (P<0.05). Significant frequency of CA/MA and MN induced by MWL was 14.21 (P<0.001) and 0.33 (P<0.001) whereas CA/MA and MN induced by DWL was 7.81 (P<0.001) and 0.13 (P<0.05) in the aqueous medium. The investigations inferred that abnormalities caused by MWL were higher than DWL both in soil and aqueous media. These toxic responses may have relied on raised heavy metal concentrations of metal-based than dye industrial wastes.

Cytogenetic effects of leachates from tannery solid waste on the somatic cells of Vicia faba.

The contamination of surface- and groundwater by the leaching of solid wastes generated by industrial activities as a result of water runoff and rainfall is a matter of great concern. The leachates from tannery solid waste (TSW), a major environmental pollutant, were examined for their possible genotoxic effects on the somatic cells of Vicia faba. Leachates were prepared from solid wastes procured from leather-tanning industrial sites, and V. faba seedlings were exposed to three test concentrations, 2.5%, 5%, and 10%, through soil and aqueous media for 5 days. The root tips examined for cytogenetic damage revealed that leachate of TSW significantly inhibited the mitotic index and induced significantly frequent chromosomal and mitotic aberrations (CA/MA) in a dose-dependent manner. The chemical analysis of TSW samples revealed that the chief constituents were chromium and nickel, which may cause genetic abnormalities. The frequency of aberrations was found to be higher in the root meristematic cells of Vicia faba exposed through the aqueous medium than those exposed through the soil medium. The results of the present study indicated that contamination of potable water bodies by leachates of TSW may cause genotoxicity. For the biomonitoring of complex mixtures of toxicants with the V. faba bioassay, the use of the aqueous medium seems to be a more promising method than the use of the soil medium.