Quantitative analysis of mercury burden in the wastewater released from dental clinics in the United Arab Emirates

ABSTRACT

Amalgam waste from dental clinics is a significant source of mercury released into the environment when it is washed down a drain or disposed of improperly. Mercury is of particular concern because of its potential adverse effects on humans and the environment. As a consequence, several measures have been adopted by dental clinics worldwide to reduce mercury discharge into the environment. The aim of this study was to quantitatively asses the mercury burden in the wastewater discharged from some dental clinics in the United Arab Emirates using a cold-vapour atomic absorption spectrometry technique. Wastewater samples were collected from 28 public cfe at Sharjah and Abu Dhabi over a period of 10-14 days. The average concentration of mercury in all samples was 317.7 microg/l, with a standard deviation of 379.7 microg/l and a range from below the method detection limit [MDL] to 1535.2 microg/l. The results show some variation in mercury concentrations between samples, depending on the type and nature of dental operations undertaken at the specific clinic from which each sample originated. Most of the wastewater released from dental clinics in the study area contains concentrations of mercury which, although lower than levels ported elsewhere in the literature, are unacceptable according to local and international environmental standards. This implies that such wastewater should not be discharged without adequate pretreatment in order to reduce wry pollution in the environment