title: Dental clinics: a point pollution source, not only of mercury but also of other amalgam constituents.
abstract: Current literature suggests that amalgam waste from dental clinics is a point-source of mercury pollution in the environment. However, apart from mercury, other amalgam constituents (e.g. Ag, Sn, Cu, and Zn) in dental clinics' wastewater have not been reported in the literature before. The objective of this study was to evaluate the concentrations of mercury and other metals in the wastewater of some dental clinics and the influent of a wastewater treatment plant in Al-Madinah Al-Munawarah (KSA). Samples were collected over a 2-month period from three dental clinics and analyzed for metals using ICP-MS. The mean concentrations of Hg, Ag, Sn, Cu, and Zn in the samples were 5.3±11.1, 0.49±0.96, 3.0±10.7, 10.0±14.5, and 76.7±106 mg L(-1), respectively. Additionally, high concentrations of other metals such as Mg (14.4±15.2 mg L(-1)), Mn (3.0±4.6 mg L(-1)), Fe (3.0±4.5 mg L(-1)), Sr (1.6±2.4 mg L(-1)), and Ba (6.9±10.3 mg L(-1)) were also found. These values are much higher than the local permissible limits. Most of the metals of interest were also detected in the influent of the wastewater treatment plant. This renders dental clinics wastewater a hazardous waste which should be properly treated before it is discharged into the environment.
authors.affiliation: Taibah University, Faculty of Science, Chemistry Department, Al-Madinah Al-Munawarah, Saudi Arabia. ashraim@taibahu.edu.sa
authors.forename: Amjad
authors.initials: A
authors.lastname: Shraim
authors.forename: Awadh
authors.initials: A
authors.lastname: Alsuhaimi
authors.forename: Jalal Thamer
authors.initials: JT
authors.lastname: Al-Thakafy
mesh_terms: D003723:Dental Amalgam / Q000032:analysis*; D003740:Dental Clinics; D018057:Dental Waste / Q000032:analysis*; D013058:Mass Spectrometry; D017744:Medical Waste Disposal; D008628:Mercury / Q000032:analysis*; D008670:Metals / Q000032:analysis; D014865:Waste Disposal, Fluid
chemical_list: D018057:Dental Waste; D017744:Medical Waste Disposal; D008670:Metals; D003723:Dental Amalgam; D008628:Mercury