Effect of Iodine on mercury concentrations in dental-unit wastewater John Michael Panganiban and Ian Jasper Ocampo
This study was undertaken to determine whether iodine used to control bacteria in dental unit wastewater could increase mercury concentrations in dental wastewater. Introduction:
Two of the major concerns in dentistry are biofilm in dental unit waterlines and the contamination of dental unit wastewater with mercury. Biofilms are microscopic communities that consist of naturally occurring water bacteria and fungi which accumulate inside things like faucets, showerheads and in thin tubes used to deliver water in dental treatment. Mercury in waterlines originated from waste of dental amalgam which is used for filling tooth that contains mercury. Since the account of local mercury discharge limits, dental facilities these days were required to install amalgam separators to limit the release of mercury into the public owned sewer system. Without dental amalgam separators, the excess amalgam waste containing mercury will be released to the sewers through the drains in the dental offices. Amalgam separators contain a proprietary resin that releases iodine at a claimed concentration of 2-6mg/L which dissolves mercury levels in waterlines. Iodine, along with other halogens readily shares electrons in covalent bonds with other atoms to complete an octet of electrons. Iodine can form stable and soluble complexes with mercury which yields mercuric iodide, resulting in elevated dissolved mercury levels in wastewater. Materials and Methods:
Part 1. Five-gram samples of ground and sieved dental amalgam with a size of 105-710 were exposed to iodine solutions at concentrations varying from 0 (control) to 20 mg/L. Samples were then, rotated end-over-end at 30rotations/min for 10 minutes and allowed to settle. Mercury levels were determined using cold vapor atomic absorption (CVAA) spectrometry at 24h and 7 days. Part 2. Deionized water was...
Please join StudyMode to read the full document