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01 Sep 2005 | Australasian Dental Practice

news > Spectrum > Page 58

The law regarding correct disposal of Amalgam

Every dental practice in Australia should be aware that they must sign a trade waste agreement with their local water board if they are allowing dental Amalgam fines/ sludge a "prescribed waste" into the wastewater system concludes a report carried out by Melbourne-based legal firm Moores Legal.


"Legally, apart from the Australian Capital Territory where it is a requirement to install an Amalgam separator to at least 95% efficiency, the other numerous Water Boards around Australia still permit Mercury and Amalgam to be dumped into wastewater," said Kevin Rogers, Business Development Manager at Universal Metals Pty Ltd parent company of Eco Cycle Industries and ARA Pty Ltd. "The requisite, in all cases however, is that a trade waste permit between the dental practice and the appropriate Water Board must be in place."

The report, undertaken by the Melbourne law firm, indicates that the process for obtaining a trade waste permit differs from state to state and water board to water board.

To obtain a permit from Sydney Water, for example, the customer must meet a number of conditions and requirements published in a document titled "Acceptance standards and threat levels". In this policy statement, the maximum acceptable standard concentration for Mercury must not exceed 0.03mg/L. To obtain a permit, customers must meet the expenses of having experts take samples of sewerage discharge to ascertain the amount and concentration of trade waste being disposed of and pay an ongoing fee for the disposal of trade waste.

Unlike other water boards however, Sydney Water does allow an exemption for businesses where the activity is "deemed a business process". Such businesses are able to discharge small quantities of wastewater into the sewerage system without negotiating a Commercial Trade Wastewater Permit under certain circumstances. In the case of dental practices, the requirements are an Amalgam separator that segregates waste Amalgam be installed. Thus, if dental practices in the Greater Sydney metropolitan area, Illawarra and the Blue Mountains install an Amalgam separator, they are not required to enter into a trade wastewater agreement with Sydney Water.

The report, based on interviews, interrogation of published documentation and wider research, indicates that other water boards are also considering compliance concessions for practices that install approved separators. In addition, a permit may not be approved if the amount of Amalgam fines being allowed into wastewater is higher than the guidelines allow unless a separator is fitted to reduce these levels.

Eco Cycle Industries supplies Amalgam separators to dental practices and offers a service for a monthly fee to fully maintain the separator and recycle the waste collected. ARA is the only company in Australasia that has the facilities to process waste Amalgam. Separators are also available from some dental manufacturers as standalone units and as part of dental units and suction systems. Amalgam used to be shipped overseas, but now this is no longer a practice open to industry, it must be processed in Australia.

"All the waste we collect is handled and processed in Australia in our state-of-the-art EPA approved facility," Mr Rogers said. "It is also a closed loop process with all distilled Mercury being reused by the dental industry.

"The ECOAS04 separating unit we provide is a reliable, unique ecological technology with no moving parts, no electronics, no motors, no power and no maintenance. It's a system based on retention, enhanced sedimentation and electrochemical reaction with a minimum separation efficiency of 99.5%. We install, change over, process and recycle, then treat the waste and recover the metals before cleaning the unit for reuse.

As part of the package, the company offers full installation and maintenance of the device and collection and recycling of the Amalgam waste. They can also collect spent Amalgam capsules, Amalgam waste from the in-line filters, lead tabs, fixer, developer and x-ray films for recycling, a total metal recycling service. They also provide help with a management maintenance program to comfort the authorities that a regular and responsible programme is in place to maintain the separator to the highest level of recovery it is capable of. A certificate of recycling is provided to each dentist upon the pick-up, replacement and fitting of the change-over unit.

Dental Amalgam remains the filling material of choice for many dental practitioners. It's a cheap, fast and durable restorative material and has been in use for hundreds of years. While patient safety concerns have been raised due to its 50% Mercury composition, the move away from Amalgam is more closely linked to its lack of aesthetics and the availability of viable alternatives as materials technology has improved.

Numerous published studies have debated side effects in patients resulting from Mercury leaching out of restorations or emitted Mercury vapour being inhaled. The dissolving of silver, tin, zinc and copper into the Mercury during Amalgamation serves to stabilise the substance, however, the fact remains that Mercury, in its pure form, is a volatile substance that must be treated with care.

The 1999 NHMRC's National Guidelines for Waste Management in the Health Care Industry, while not having the authority of law, states that "dental practitioners must install Amalgam separators, capable of 95% separation, so as to treat all wastewater streams containing Amalgam residues from all dental chairs at the premises."

Significant progress has been made in recent years to improve the handling of Mercury in dental surgeries resulting in a far safer working environment. Few new graduates would remember the days where the Mercury, in its natural liquid form, was manually combined with an alloy pellet and then placed in a capsule and loaded into an Amalgamator. The resultant mix was then placed on a circular cloth, gathered up and squeezed, with the excess Mercury permeating through. As it was packed into the prep, even more excess Mercury would bead onto the surface of the restoration to be wiped away with a cloth.

The pre-dispensed capsule system in use today significantly reduces the occupational health and safety risks that existed with Amalgam usage in the past. The Mercury is activated within a sealed capsule which combines it with the alloy where it undergoes trituration and Amalgamation. It is then ready to be loaded into the Amalgam packer and dispensed into the prep.

The dosing is also far more accurate with the modern capsule-based system and there is little excess Mercury. However, Mercury used in dental Amalgam is still recognised as a contributor to overall heavy metal pollution of the environment.

Mercury has been identified by the World Health Organization as the number one environmental poison, and by far the largest single contributor of Mercury to waste water is from dental offices. One gram of Mercury, which approximates the amount released into wastewater everyday by an average dentist, can contaminate a billion litres of water to a concentration above an acceptable level.

The Mercury released into the waste system can end up in the ocean. Mercury ends up in predatory fish, through eating other fish and creatures which contain Mercury because they are on the top of the food chain in the oceans, lakes and rivers which then in turn end up on the dinner table. Recent Mercury levels tested in shark fins were 42 times the maximum limit. Fish such as Sword fish, Tuna, Shark, etc, can have levels of Mercury more than million times higher than the surrounding environment. The Current Affair program aired on August 9th 2005 highlighted this issue and confirms the need to responsibly recycle any Mercury-bearing wastes. The Methyl Mercury is the typical form and it is very dangerous for pregnant women and young babies as it blocks nerve cell formation, destroys existing nerve cells in the brain and causes neurological deficiencies. There was also a recent scare about high levels of Mercury in dolphins in South Australia (446 ppm highest in the world).

It therefore follows that as healthcare providers, dentists also have a moral obligation to prevent the release of Mercury into the environment. The typical method employed is to use an Amalgam separator, like the ones maintained by Eco Cycle, the separators that can be purchased with your dental chair, or are available from other manufacturers.

As water becomes a much more precious resource in Australia and water recycling and reuse becomes more prevalent, the current legal obligations to reduce the quantity of heavy metals entering the water table will no doubt increase as will the policing of offenders.

Conclusion

As a minimum today, dental practices must have a trade waste agreement in place to comply with the legal requirements of disposing of Amalgam and Mercury into the wastewater system. In the ACT, an Amalgam separator is mandatory while in Sydney, a separator negates the need for a trade waste permit. In all states and in all cases however, the trapping of Amalgam and preventing it entering the water system will fulfil a broader moral obligation to the environment.

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