The behavior of dental health personnel was examined with regard to the handling and proper disposal of
wastes generated at common dental clinics, and some of the amounts of waste they produce were
estimated. In January 2002, a random sample of 37 dental clinics was chosen in the cities of Ramallah and
al-Bireh. The visited clinics were distributed between 31 private practices and six public/NGO dental
clinics. The dentists were asked about the methods they follow in disposing and discarding of amalgam
wastes. An average dentist is estimated to place two small, seven medium and nine large amalgam
restorations releasing 22.6 grams of mercury each week. The majority of amalgam wastes ended up in
trash or drai

Khatib, Issam

FADA - Birzeit University

  
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Assessment of waste amalgam management in dental clinics in Ramallah
and al-Bireh cities in Palestine
Issam A. Al-Khatib a;Rana Darwish a
a Environmental Health Unit, Institute of Community and Public Health, Birzeit University, West
Bank, Palestine
To cite this Article Al-Khatib, Issam A. andDarwish, Rana(2004) 'Assessment of waste amalgam management in dental
clinics in Ramallah and al-Bireh cities in Palestine', International Journal of Environmental Health Research, 14: 3, 179 —
183
To link to this Article: DOI: 10.1080/09603120420002000218598
URL: http://dx.doi.org/10.1080/09603120420002000218598
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Assessment of waste amalgam management in
dental clinics in Ramallah and al-Bireh cities in
Palestine
ISSAM A. AL-KHATIB and RANA DARWISH
Environmental Health Unit, Institute of Community and Public Health, Birzeit University, West Bank, Palestine
The behavior of dental health personnel was examined with regard to the handling and proper disposal of
wastes generated at common dental clinics, and some of the amounts of waste they produce were
estimated. In January 2002, a random sample of 37 dental clinics was chosen in the cities of Ramallah and
al-Bireh. The visited clinics were distributed between 31 private practices and six public/NGO dental
clinics. The dentists were asked about the methods they follow in disposing and discarding of amalgam
wastes. An average dentist is estimated to place two small, seven medium and nine large amalgam
restorations releasing 22.6 grams of mercury each week. The majority of amalgam wastes ended up in
trash or drain.
Keywords: Amalgam; dental waste; management; developing countries; Palestine.
Introduction
The major hazardous wastes that are produced at dental clinics include dental amalgam
restorations, X-ray wastes, chemical disinfectants, sharps as well as blood soaked dressings
(EPA 2000). Amalgam has been widely used, by dentists, as a dental ﬁlling material for over
100 years (Eley 1998). Amalgam ﬁllings consist of 1 : 1 mixture of metallic mercury and an alloy
powder of silver, tin or copper. Its content of mercury has created a long-term debate regarding
its use until today. Besides its known eﬀects on health, mercury creates an important
environmental impact that should be dealt with (Dental Recycling North America) (DRNA
2000).
The mercury in amalgam can be released into the environment through various channels,
mainly air, water, and solid waste (NCDPP 2001). It is worth mentioning that the metallic
mercury in amalgam is considered relatively non-toxic. However, when it is released into the
environment, certain species of bacteria may convert part of it into methyl mercury, which is
known to be a potent neurotoxin (NCDPP 2001). Furthermore, the amalgam, when it is mixed
with general waste that is incinerated, will cause the mercury to volatilize and enter the
atmosphere (National Wildlife Federation 1999). In addition, the discarded amalgam waste
that ends up in landﬁlls may lead to soil and water contamination (National Wildlife
Federation 1999). Dental clinics are also responsible for the mercury content in wastewater,
since the amalgam particles that are rinsed down the drain or escape the poorly maintained
Correspondence: I.A. Al-Khatib, Environmental Health Unit, Institute of Community and Public
Health, Birzeit University, West Bank Palestine. Fax: 00972-2-2951181; E-mail: ikhatib@birzeit.edu
International Journal of
Environmental Health Research 14(3), 179 – 183 (June 2004)
ISSN 0960-3123 print/ISSN 1369-1619 online/04/030179-05 # 2004 Taylor & Francis Ltd
DOI: 10.1080/09603120420002000218598
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chair side dental unit traps and ﬁlters reach eventually the wastewater (National Wildlife
Federation 1999). A pollution prevention agency in the Bay Area in California pointed out that
a small sized ﬁlling (which was considered as one unit) contains 0.55 g of mercury (Emerging
Infections Program (EIP) 2000; Barron 2001). Similarly, a medium ﬁlling of two units would
contain about 1.10 g of mercury.
In the Palestinian context, data is not available regarding the number of the newly placed
amalgam ﬁllings or even the removed old restorations in dental clinics. No local study is
available about the individual practices of dentists in their dental oﬃces, and whether they try
to minimize the eﬀects of mercury released within the waste of these ﬁllings. This data presented
in this paper investigates these issues especially in the absence of health regulations and law (Al-
Khatib 2002).
Materials and methods
The study was carried out during the month of January 2002, through ﬁeld visits to the various
randomly selected dental clinics, where structured interviews were conducted with the dentists
using a pre-prepared questionnaire. The interviews lasted from 20 to 30 min.
The total number of registered dental clinics in Ramallah district in the year 2001 was 106,
distributed between public/Non-governmental Organizations (NGO) and private sectors
(Palestinian Dental Association 2001). Of these 106 clinics, 94 are found within the borders
of Ramallah and al-Bireh towns; 86 of them are private, and eight clinics belong to public
institutions or NGOs (Governmental (Gov) – NGO’s – charitable and United Nations Relief
and Works Agency (UNRWA). The 12 remaining clinics are registered in the rural
surroundings.
This study focused on the clinics within the urban centres only, because of the diﬃculties faced
in reaching the rural areas due to the presence of diﬀerent military checkpoints cutting oﬀ
Ramallah and al-Bireh from the rural surroundings. The study sample included 37 dental clinics
out of the 94 counted in Ramallah and al-Bireh. Thirty-one private clinics were randomly chosen
from the 86 dental clinics included within the private sector. The institutional dental clinics were
all included, since they were few, except for two. The dentist serving one of the NGO clinics was
abroad at the time of the study. The other clinic is run by UNRWA, and is situated in al-Jalazon
refugee camp, which could not be reached due to the military checkpoint there.
The ﬁrst part of the questionnaire included data on country and date of graduation, gender
of dentist, type of degree (Bachelor or higher degree), type of clinic, the starting date of the
clinic, number of staﬀ at the clinic, and whether the dentist or the staﬀ were vaccinated against
Hepatitis B. The last item was included due to the risks that are present for the health personnel
who handle dental wastes, especially sharps, whether it was the dentist himself/herself or staﬀ
such as nurses, assistants or waste handlers. The second part of the questionnaire focused on
the various types of waste that are generated by the dental oﬃces on daily basis.
Amalgam waste questions focused on the average number and size of newly placed amalgam
ﬁllings per week, as well as the average number of the removed old amalgam ﬁllings per week.
Dentists were also asked about what type of amalgam they used, since the amalgamated
capsules are much safer to use than the elemental or raw mercury amalgam, which could be
subjected to accidental spills. Additional questions were concerned with the disposal of the old
removed or the extra newly placed amalgam ﬁllings.
Data was entered and analysed using the statistical program SPSS 8.0. Simple frequencies,
means and cross tabs were used. Chi-square and Anova tests were utilized to test diﬀerences in
180 Al-Khatib and Darwish
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waste disposal between various observed variables such as gender of dentist, year and country
of graduation, type of degree and type of clinic.
Results
The most common types of restorations used in the dental oﬃce are amalgam and composite.
The composite ﬁlling is an esthetic ﬁlling used mainly for the anterior teeth. However, new
brands are being gradually introduced for the restoration of posterior teeth. They are more
expensive than amalgam. The majority of dentists (89.2%) said that they use both types of
restorations while 10.8% conﬁrmed that they stopped using the amalgam at all. Among those
who use amalgam, 42.4% use elemental mercury amalgam, whereas 57.6% use amalgam
capsules. It is worth mentioning that the elemental mercury amalgam is less expensive than the
capsulated one, which could explain the fact that no signiﬁcant correlation was found between
the type of amalgam and the other variables like the type of clinic, country and year of
graduation, age of the clinic or the gender of the dentist.
The average number of removed old amalgam ﬁllings per week as well as the newly placed
amalgam is illustrated in Table 1. This indicates that a general dental practitioner in Ramallah
city places about two small, nine medium, and seven large amalgam ﬁllings each week. With a
simple calculation based on the above mentioned information from the pollution prevention
agency in the Bay Area in San Francisco (Envirosense 2001), this number of ﬁllings would
produce 22.55 g of mercury from amalgam waste per week, assuming that each unit of
amalgam ﬁlling releases 0.55 g of mercury.
Modes of disposal of the extra newly placed amalgam ﬁllings are shown in Table 2. Likewise,
the ﬁnal destination of useless non-contact amalgam ﬁllings is also shown in the same table.
The latter ﬁllings are usually dry or extra wet ﬁllings due to the disproportion of the mercury
with the alloy mixture of silver, tin and copper. Dentists who use elemental mercury amalgam
face this kind of unwanted discarded ﬁllings more often than their colleagues who use the
capsulated amalgam.
As for the disposal of the old removed amalgam restorations, the responses of the
interviewed dentists are illustrated in Table 3. The relation between the disposal of old amalgam
ﬁllings and the degree of the dentist (Bachelor or Master) was found to be signiﬁcant
(P=0.022).
Discussion
This study included a sample of 37 dental oﬃces from a total number of 94 located within the
boundaries of Ramallah and al-Bireh cities, representing about 39.36% of all dental clinics. The
Table 1. The average number of old and new amalgam per week vs. type of clinic
NGO/Public
clinics
Private
clinics
Total
mean
Average number of removed old amalgam/week 3.4 4.13 4.03
Average number of newly placed amalgam/week 26.83 15.77 17.57
181Assessment of waste amalgam management in dental clinics
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study included three dentists with a Master degree out of the original number of 11 specialists
who hold this degree in diﬀerent dental sciences in Ramallah area. Therefore, this sample can
be considered representative for the dental clinics found in the urban areas of Ramallah
District.
The results showed that the economic factor played an essential role in many aspects. The use
of elemental mercury amalgam instead of the safer encapsulated amalgam goes back to the fact
that this type of amalgam is less expensive than the capsules, even though accidental spills can
put the dental personnel at risk of mercury toxicity. In addition, many patients seem to prefer
this ﬁlling to other diﬀerent kinds of teeth restorations because it is not costly.
The estimated amount of mercury released from amalgam wastes for one general dental
practitioner in a week is 22.6 grams of mercury. This provides a good idea about the huge
mercury quantities that can be released into the environment if that number was multiplied by
the total number of the scattered dentists throughout 48 working weeks in a year. This reality
matches the global concern about the amounts of mercury in amalgam waste that are generated
Table 3. Distribution of dentists by means of old amalgam disposal
Disposal of old amalgam
How do you deal with old amalgam? No of dentists %
In drain passing through coarse ﬁlter 6 16.7
Caught in ﬁlter then thrown in trash 8 22.2
Distributed between ﬁlter, drain & trash 20 55.5
Caught in vacuum ﬁlter 1 2.8
Thrown in trash 1 2.8
Total 36 100.0
Table 2. Modes of disposal of extra newly placed and non contact amalgam
Disposal of extra newly placed
amalgam
Disposal of non contact
amalgam
How do you deal with non-contact
amalgam?
No of
dentistsa %
No of
dentists %
Thrown in trash 18 54.5 25 75.7
In drain & trash 2 6.1 –
Returned to capsule then trash 9 27.3 2 6.1
Separate bottle 4 12.1 3 9.1
Down the sink – 1 3
Rareb – 2 6.1
Total 33 100 33 100
aFour dentists of the sample (37 dentists) were excluded because they do not use amalgam.bRare cases who face non
contact amalgam.
182 Al-Khatib and Darwish
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and discharged into the environment. In the United States for instance, the American Dental
Association has stated that a typical dentist removes between 700 and 800 ﬁllings per year
(DRNA 2000). Normally, the amalgam recycle companies contribute a lot to lower magnitude
of mercury side eﬀects.
In the current Palestinian situation, the majority of amalgam wastes end up in trash as well as
down the drain, especially with the removal of old amalgam ﬁllings. Nevertheless, in the
absence of the above mentioned solutions, the presence of good chair side traps and following
the best management practices would reduce the amounts of mercury that are generated at
dental oﬃces, thereby minimizing its negative impact on the environment.
Conclusion
The current situation shows that amalgam wastes are dumped in the general trash, which is
placed in the badly controlled landﬁll in Ramallah city. This will lead to the evaporation of the
mercury vapors into the air since garbage is being burnt on regular daily basis in an open site.
Also, its presence in the landﬁll may lead to water and soil contamination.
Huge amounts of dental wastes are generated month after month and year after year. The
accumulated eﬀects of such environmental burdens are often overlooked. In the absence of
national services and regulations, amalgam wastes will continue ending up in trash and sewer
systems. Therefore, a national collaborative eﬀort should be made to minimize the eﬀects of
solid and liquid wastes to the minimum, and to address these threats in comprehensive, eﬀective
ways. An environmentally responsible dental oﬃce can help in restoring a healthier
environment and can always make a diﬀerence.
References
Al-Khatib, I. (2002) Overview of Medical Waste Management in Palestine. Institute of Community and
Public Health, Birzeit University, West Bank, Palestine.
Barron, T. (2001) Dental Mercury Pollution Prevention and Waste Management Practices for the Dental
Oﬃce. Web page article http://www.des.state.nh.us/nhppp/mercurysurvey.pdf.
Dental Recycling North America (DRNA) (2000) The Problem of Mercury. Web page article http://
www.drna.com, accessed 24 December 2001.
Eley, B.M. (1998) The Future of Dental Amalgam. Great Britain: Athenaeum Press.
Emerging Infections Program (EIP) Associates (2000) Mercury Amalgam Treatment Technologies for
Dental Oﬃces. Web page article http://www.state.ma.us/dph/bhsre/mcr/98/mcr98.pdf.
Envirosense, EPA (2001)Managing Hazardous Waste Generated by Dental Clinics. Web page article http://
www.es.epa.gov/program/regional/state/minn/mntap/mntap47.html.
EPA (2000) U.S. Environmental Protection agency How to Handle Dental Wastes. Web page article http://
www.epa.gov.
National Wildlife Federation (1999) The Environmentally Responsible Dental Oﬃce. Web page article
http://www.nwf.org/watersheds/pdf_documents/bookletpg1-16.pdf .
North Carolina Division of Pollution Prevention (NCDPP) (2001) Dental Waste Management. Web page
article http://www.p2pays.org/ref/01/00020.htm.
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183Assessment of waste amalgam management in dental clinics
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Assessment of waste amalgam management in dental clinics in Ramallah and al-Bireh cities in Palestine

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