Awareness among sewage workers to occupational exposure is growing slowly in many developing countries. Lead (Pb) and cadmium (Cd) are present in sewage water and workers are exposed to these metals as a result of unprotected handling. These heavy metals exposures are responsible for DNA damage and lowering blood total iron (Fe) concentration. Zinc (Zn) is an element for promoting metallothionine expression and binds the free Cd. The total suspended solids (TSS), total dissolved solids (TDS), Pb, and Cd were estimated in sewage water. The whole blood Zn and Fe concentration and Pd and Cd were also estimated. Genotoxicity as indicated by DNA damage was studied by comet assay. It was observed that there were significant differences () of Pb and Cd concentration in blood for the sewage workers when compared with control population. DNA damage was also observed to be significantly () higher in the exposed groups but their blood Fe concentration was significantly lower, which may be the reason for their tendency for retention of blood Cd and make them more susceptible. This study also indicated that aged workers had higher blood Zn concentrations as compared to the younger (working < 20 years) workers. This may indicate a possible adaptive response. The present study proposes that younger (working < 20 years) group is more susceptible as compared to aged group (working > 20 years). 1. Introduction Municipal wastewater has already been reported as genotoxic [1–3] and has been frequently found to be mixed with liquid waste from small scale industries [4]. This multiple effluent mixture has deleterious somatic effect [5] and also has adverse genetic effect [6]. People who are contaminated with this wastewater are at a higher risk of cancer development [7]. In recent years, detection and assessment of occupational health impact and different health hazards have become an area of growing importance, in which it is important to know whether workers have adopted adequate safety measures during the period of working [8]. Apart from organic pollutants, sewage water has also been reported to be contaminated with different metals especially Pb and Cd. In urban area, the large number of local automobile repair shops has led to increased Pb contamination in sewage water [9]. Cd compounds have also been considered mutagenic and in vitro studies in human cells have shown increased damage in chromosomes as well as DNA strand breaks [10]. Cd exposure also reportedly causes anemia in human. Blood Fe level is an important indicator for anemia in people subjected to heavy metal
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