<>Objective:  Developing a line cleanser that will control the chemistry of dental waste and consequently increase the performance of amalgam separators by capturing small mercury-amalgam particles. This work is funded under contract#2R44DE14010-02 by the NIDCR. <>Methods:  Using several clinics, ADA Technologies Inc. has characterized the mercury particle size by segregating it into the following size fractions: large particles (P>10mm), fine particles (0.45mm<P<10mm), colloidal particles (0.02mm<P<0.45mm), and dissolved mercury (P<0.02mm). The large particles and some fine particles are removed by amalgam separators, and typically this accounts for the majority of mercury waste. However, the contribution from small mercury particles can be significant, see Figure 1. ISO-certified amalgam separators alone do not effectively remove small particles, so they are regularly discharged into the municipal waste.

<>Results:  In a patented process the addition of a specifically formulated line cleanser has reduced most of the fine and colloidal mercury-amalgam found in dental wastewater, see Figure 1. After ADA's line cleanser is added the total mercury decreased by 55-95%. During these tests the line cleanser normally used by the dental clinic was still being used. Oxidizing agents found in many line cleansers increase dissolved mercury concentrations and the mercury discharged. ADA's line cleanser avoids formation of dissolved mercury by utilizing non-oxidizing ingredients. Therefore, when ADA's line cleanser replaces the office's current line cleanser, mercury discharge is further decreased. In fact, in samples with less than 45% dissolved mercury ADA's line cleanser decreased mercury concentration by 80-95%. <>Conclusions:  The new line cleanser used with a sedimentation-style amalgam separator, such as the ISO certified BullfroHg^TM, will lower the mercury emissions from dental offices with little to no added cost or activity to dental staff. Unlike current stand-alone ISO-certified separators the combination of separator plus ADA's innovative line cleanser addresses all forms of mercury in dental wastewater.