Dental Offices and Septic Systems (Ohio and Michigan)

The EPA Dental Rule has exempted dental facilities that discharge into septic systems. Some states have not exempted septic systems. This blog refers to the states of Ohio and Michigan.  Amalgam dissolves slowly on water. The table below is a snapshot of the levels of mercury that can be generated overnight using various line cleaners.

Line Cleaner Study Results
Concentration of Mercury
Dissolved in ng/L By each Product
Amalgam Dissolution
Times
Line Cleaner Quantity pH 30
Minute
16
Hours
60
Hours
Tap Water (Control) 0.529 7.1 4610 279000 371000
Pure Vac 0.509 2.6 15300 461000 584000
Clean Linz 0.511 6.9 4100 309000 403000
Vac Attack 0.504 11.0 33900 467000 616000
OxeVac 0.511 3.1 20200 403000 503000
Vacusol 0.514 9.0 13600 304000 364000
Precision Clenz 0.518 7.5 7120 394000 483000
Power Linz 0.528 7.0 4670 289000 368000

More detail regarding this study will be provided in the next blog.  The quantity of amalgam used in the test was 0.5 grams.

What is important is that over time the dissolved mercury will increase as more amalgam enters the septic system.  The discharge of mercury into the drain field, if the system is working properly, will be over 1 part per million.  The water from the drain field will go in two directions.  It will go to ground water or to a natural water way.  Both situations are unacceptable to any state agency.

If the septic water goes to ground water, it will make the ground water unacceptable for drinking. It will become NON-POTABLE WATER. If the water discharges to a natural waterway, the waterway will be considered contaminated.  The soil that adsorbs the mercury will be a hazardous waste site.  Discharging into a septic system may be a violation of a state regulation.

In Ohio and Michigan any dental waste that contains amalgam or mercury must be contained and is not permitted to discharge.  This means that use of a separator is not a solution.  The dental facility MUST contact their state agency regarding any rule that they may have for septic systems.  Since dental facilities are now considered an industry, they may fall under industrial regulations for septic systems.

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