Exploring the potential interference of estuarine sediment contaminants with the DNA repair capacity of human hepatoma cells.

Estuaries may be reservoirs of a wide variety of pollutants, including mutagenic and carcinogenic substances that may impact on the ecosystem and human health. A previous study showed that exposure of human hepatoma (HepG2) cells to extracts from sediment samples collected in two areas (urban/industrial and riverine/agricultural) of an impacted estuary (Sado, Portugal), produced differential cytotoxic and genotoxic effects. Those effects were found to be consistent with levels and nature of sediment contamination. The present study aimed at evaluating whether the mixtures of contaminants contained in those extracts were able to modulate DNA repair capacity of HepG2 cells. The residual level of DNA damage was measured by the comet assay in cells exposed for 24 or 48 h to different extracts, after a short preexposure to a challenging concentration range of ethyl methanesulfonate (EMS), as a model alkylating agent. The results suggested that the mixture of contaminants present in the tested samples, besides ...