Stress response of heavy metal mixture present in wastewater and leachate on heat‐shock protein 47‐transfected cells

Abstract

Heavy metals present in water environment and hazardous sites as single compounds or mixture may drastically affect human health. In the present work, we investigated the risk assessment of wastewater effluents and leachate with a focus on three heavy metals-nickel (Ni), cadmium (Cd), and lead (Pb)-and their combined effect on mammalian cells, using Chinese hamster ovary cells transfected with the heat-shock protein (HSP) 47 promoter. The heavy metal mixture model was designed based on the concentrations of metals in wastewater effluents and leachate sampled in Tunisia. Using a ternary diagram, we investigated the stress response of the interaction model. This research indicated that the single heavy metals induced the stress response on HSP(+) cells even at concentrations lower than the local and international guidelines. Differences in water quality likely influenced the metal responses such that the organic composition of the leachate increased the stress response induced by the heavy metals exclusively, whereas the effluents included organic compounds that were able to mask the heavy metal effect. The mixture characterization discovered the key role played by the high levels of Ni or combination of Cd and Pb to induce the highest stress response following 3-h incubation. Heat-shock protein 47 has proven its effectiveness for assessing the heavy metal mixture effect even at low concentrations. Furthermore, the combination of a bioassay system with a statistical model proved extremely useful for better understanding the major contributors to the stress response of the mixture.

Biomarkers of pollution in soils irrigated with wastewater in Tunisia

“…Nevertheless, higher concentrations above 1% caused a cytotoxic effect even significant at 20% concentration. The stress response induced by the TWW samples might be related to the Cd content (Table 1) combined to a mixture of heavy metals responsible of a significant stress response in accordance with our recent works [10].…”

“…Moreover, the pH values for the irrigated soil vary between 7.82 and 8.17. The highest values, which could favor metal binding to biomass [10], are localized in depth. Overall, the heavy metal levels in the irrigated soil were higher than the control soil (C10 and C40) due to the prolonged irrigation (20 years).…”

Heat shock protein 47 stress responses in Chinese hamster ovary cells exposed to raw and reclaimed wastewater

“…This increase in the stress response is likely to be associated with the release of bacterial by-products (LPS endotoxin) as reported by Guizani et al 2009 [26]. Ben Fredj et al 95 2010 [31] reported that, in certain conditions, presence of organic matter (bacterial by-products in this case) masks the heavy metal effect.…”

Health Effects Associated with Wastewater Treatment, Reuse, and Disposal

“…Nickel, lead, and cadmium were three heavy metals found in wastewater effluents collected in Tunisia (Ben Fredj et al, 2010). If not removed from the treated effluent stream prior to being discharged into the environment, the mixture of the heavy metals had very damaging health effects.…”