Investigation of heavy metal concentrations in wastewater of dental units: Ecological risks

Dentistry is one of the health-care centers that can have a major contribution in the release of microbial and chemical pollutants into the environment due to the inefficiency of equipment and the lack of appropriate standards. The present study was conducted with the aim of investigating the concentration of common heavy metals in the wastewater of dental units and investigating ecological risks. A total of 45 samples were selected from 11 dental units in Jiroft. Sampling was carried out for two weeks. Four wastewater samples and one inlet water sample were collected from each dental unit. Based on the results, there was a significant difference between the average concentrations of copper (P = 0.01) and silver (P = 0.001) and the standard level. There was a significant difference between pH (P < 0.001), EC (P < 0.001), TDS (P < 0.001), TSS (P < 0.001), COD (P < 0.001) and turbidity (P < 0.001) with the standard level. CD and mCF analysis indicated that two dental centers had moderate pollution, and three centers had high pollution degree. Also, 9 out of 11 dental units did not have amalgam separation filters. The results indicate that dental wastewater should be treated before discharge due to the high presence of heavy metals. Therefore, dental wastewater management, establishing new standards, and replacing harmless materials in order to reduce the entry of heavy metals into the wastewater seem necessary.