Dental Separator Study

Purves Environmental Inc. had conducted a study on Amalgam Separators, below is their statement on the purpose of the study, and please find the PDF attached below for their findings.


To determine the effectiveness of Amalgam Separators used to remove Mercury from the environment.

Amalgam Separators were designed to remove amalgam from the environment and are effectively removing 99+% of the solid metal from the dental discharge. After an exhaustive study of dental office discharges at the street location (manholes), it became clear that very large quantities of mercury were still entering the environment (10 to 1600000 ng/L). These numbers indicated that there was still an issue with mercury entering the environment. In none of the separator studies performed by various states, academic and/or private companies is dissolved mercury examined. The ISO 11143 standard only examines physical separation. This type of separation assumes that the remaining 1-5% of amalgam (equal to 3400 pounds of dissolved mercury annually) discharging into the environment is not an issue or a hazard. The data below may change that assumption.

Purves Environmental Inc. sampled several separators in various offices only to find that the level of total mercury discharging to the environment at the separators ranged from 65,600 ng/L to 17,500,000 ng/L. This data is not addressed by the Dental community or the separator manufacturers. Separator designs were first established under the false assumption that the mercury remaining in the discharge was not an issue and that it remained in a solid form that could easily be removed at a waste water treatment plant. The other assumption that is now applied is; the discharge flow from a dental office is so small that the high levels of mercury would be diluted when mixed with the influents from other discharges. The premise of this study and research was to accumulate data from operating systems and determine the best separation systems now employed to handle the mercury discharge. It is focused primarily on dissolved mercury.

Dissolved mercury is far more dangerous to humans and wildlife than mercury which is bound to solid particles. Dissolved mercury is more readily absorbed by humans and aquatic organisms than mercury bound to solids. Dissolved mercury is converted into Methyl Mercury in the body through normal biological processes. The Methyl Mercury formed is far more dangerous than elemental mercury to humans because it attacks the Central Nervous system and causes a Parkinson’s like syndrome. In aquatic life (primarily fish) this process occurs in the same manner. Since fish is a food source for humans, the Methyl Mercury in the fish is even more readily absorbed by humans and can become a danger to human consumption. This is the primary reason that the consumption of fish in the Great Lakes and many rivers and streams is limited by EPA and many state natural resource departments. For this reason the mercury discharge limit concentration was reduced to 12 ng/L and 1.3 ng/L (Great Lakes) to protect both humans and wildlife.

Purves Amalgam Study 2 Nov 5, 2014