Versão online: http://www.lneg.pt/iedt/unidades/16/paginas/26/30/185
Comunicações Geológicas (2014) 101, Especial II, 1011-1014
IX CNG/2º CoGePLiP, Porto 2014
ISSN: 0873-948X; e-ISSN: 1647-581X
Characterization, treatment proposal and metal recovery in
waste of active implantable medical devices
Caracterização, proposta de tratamento e recuperação de metais
dos resíduos dos dispositivos médicos de implante ativo
R. Guimarães1*, J. Carvalho1, V. Leal1, A. J. Guerner Dias1
Artigo Curto
Short Article
© 2014 LNEG – Laboratório Nacional de Geologia e Energia IP
Abstract: This study analyses the feasibility of active implantable
medical devices waste treatment. After contacts with some
responsible for the management of these devices in Portugal, it is
possible to verify that none have a treatment process for this devices
after been used, so they are stored in the hospitals or they can be
delivered to the patience, if requested.
The number of devices implanted increase every year and
consequently the quantity of waste produced is higher, so is
important propose an efficient treatment process for this waste.
With the aim of development an efficient treatment process was
realized a characterization of active implantable medical devices.
Several analyses of the device´s components were realized with
special attention on printed circuit board because of its complexity
and high economic value.
The results indicate that printed circuit board from active implantable
medical devices present quantities of precious metals, particularly
gold (Au), superiors of printed circuit board of other electronic
devices.
It is possible to conclude that exist technology able to valorize the
active implantable medical devices waste, since these are subject to a
pretreatment (disinfection) after their explantation.
Keywords: Active implantable medical device, Metal recovery,
Printed circuit boards, Waste electric and electronic equipment,
Precious metals.
Resumo: Este estudo analisa a possibilidade de tratamento dos
resíduos provenientes dos dispositivos médicos de implante ativo.
Através de contactos efectuados com vários responsáveis pela gestão
destes dispositivos em Portugal, verificou-se que nenhum deles
dispõe de um processo de tratamento para estes dispositivos depois
de terem sido utilizados, ficando por isso armazenados nos hospitais
ou podendo ser entregues ao paciente, se este o requisitar.
O número de implantes destes dispositivos tem aumentado ao longo
dos anos, o que representa um consequente aumento dos resíduos
produzidos, justificando-se desta forma a necessidade de estabelecer
um processo de tratamento eficiente.
Este estudo focou-se na caracterização dos dispositivos médicos de
implante ativo com o objectivo de propor um método de tratamento
para os resíduos dos mesmos.
Foram feitas várias análises aos componentes dos dispositivos com
especial atenção às placas de circuito impresso devido à sua
complexidade e valor económico.
Os resultados obtidos permitem afirmar que as placas de circuito
impresso destes dipositivos apresentam valores de metais preciosos,
principalmente ouro (Au), significativamente superiores às placas de
circuitos impressos de outros dispositivos electrónicos.
Conclui-se que existem tecnologias que permitem a valorização
destes resíduos, desde que estes sejam sujeitos a um pré-tratamento
(desinfecção) após a sua explantação.
Palavras-chave: Dispositivos médicos de implante activo,
Recuperação de metais, Placas de circuito impresso, Resíduos de
equipamento eléctrico e eletrónico, Metais preciosos.
1
Departamento de Geociências, Ambiente e Ordenamento do Território.
Faculdade de Ciências da Universidade do Porto. Rua do Campo Alegre 687,
4169-007 Porto. Portugal.
*
Corresponding author / Autor correspondente: [email protected]
1. Introduction and objectives
Population growth is more pronounced every day who
leads to the rise of consumption, generating many
problems in relation to treatment and final destination for
the waste produced. With the improvement of life
conditions, more waste is generated, particularly hospital
waste, turning to several legal and social issues, in
relation to environmental effective treatment solutions.
The technology industry growth leads to inordinate
use of metals and ensure their supply is seen as critical
(UNEP, 2010). In addition, that fact leads to an increase
of waste electric and electronic equipment (WEEE)
which rounds 8.3 to 9.1 million metric tons with an
annual increase of 3–5% in twenty seven countries of
European Union (Huisman et al., 2008).
Despite the implementation of waste electrical
electronic equipment and the Restriction of Hazardous
Substances (RoHS) directives, to properly manage evergrowing stream of WEEE, the most of developing
countries not introduce these directives yet (European
Parliament, 2003).
Medical devices are contained on 8th category of
EEE in the directive 2012/19/EU of the European
Parliament and of the Council of 4 July 2012 on WEEE,
which states that recycling goals shall not apply to
“medical devices and in vitro diagnostic medical
devices, where such devices are expected to be infective
prior to end of life, and active implantable medical
devices” (article 2, point 4, paragraph g), where
pacemakers and implantable cardioverter defibrillator
(ICD) are included. Due this fact, there’s no actual
solution to recycle these devices.
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The hospital waste is divided in four groups (Agência
Portuguesa do Ambiente, 2011), in which, groups I and II
obey in an efficient way the current waste management
hierarchy, while groups III and IV, after a previously
treatment, are sent for incineration or landfilled.
The active implantable medical devices (AIMD), after
explantation and disinfection, belong to group III.
According to European Waste Catalogue (EWC)
(Ministério
da
Economia,
da
Agricultura,
Desenvolvimento Rural e Pescas, da Saúde e das Cidades,
Ordenamento do Território e Ambiente, 2004), these
devices are classified in chapter 18 of this catalogue and
they do not represent a specific waste flow. Therefore, it
arises the necessity to identify their components, in
particular relevance for metals components, with the aim
of development an efficient process of treatment.
It’s known that precious and special metals are decisive
for increasing devices functionality and then is expectable
that the use of gold and other technology metals grow
further. Electronics represents 12% of total annual mine
production of gold.
Their efficient recovery from
electronic scrap represents a significant potential recycling
source. Gold’s demand had an increasing during the last
decade, not only due to the jewelry market, but also due to
the increasing uses of gold in industrial, as well as medical
devices (Hagelüken & Corti, 2010).
Printed circuit boards (PCB) are the essential parts of
electronic devices and hold the major fraction of metals
present in WEEE. PCBs are particularly rich in copper and
precious metals with high economic potential (80% of the
total intrinsic value even though the amount is less than 1
wt. %, such as gold (Park & Fray, 2009). Every year 300
ton of gold are used in electronic components such as
integrated circuits, contacts and bonding wires (Hagelüken
& Corti, 2010).
The rigid PCB multilayers are fabricated from copperclad dielectric materials. The dielectric consists of an
organic resin reinforced with fibers. The organic media can
be of a wide formulation and include flame-retardant
phenolic, epoxy, polyfunctional epoxy, and polyimide
resins (Harper & Sampson, 1994). Multilayer circuits are
produced by building a structure of conductive layers and
are filled with the same metallization in a separate
screening step (Minges & Committee, 1989).
The gold is not deposited on the PCB surfaces directly
but on an aluminum or titan pre-coat layer (Harper &
Sampson, 1994). Conductors that use gold are easily
bonded and when alloyed with small amount of platinum
or palladium, it is easy to solder and form reliable joints
(Minges & Committee, 1989).
In AIMD are included the pacemaker, the ICD and
others. In this study only pacemakers and ICDs were
included.
A pacemaker is an electronic biomedical device that
can regulate the human heartbeat when its natural
regulating mechanisms break down. The durability of
these devices varies from 5 to 10 years due the degree of
battery’s use. In Portugal, the annually average number of
implanted devices is about 7200 (Direção Geral de Saúde,
2013).
The pacemaker´s motherboard contains all the
electrical circuitry of the pacemaker and using
hybridization, all components are combined to form a
single complex circuit, allowing the use of materials which
cannot be included in a monolithic integrated circuitry.
The primordial conductor used in pacemakers is gold
because of its stable and inert status, does not oxidize or
migrate (Minges & Committee, 1989).
An ICD is a small device that is placed in the human
body, specifically in chest or abdomen. Are used to detect
dangerously fast heartbeats and give a lifesaving shock to
correct the heart’s rhythm. Like pacemakers that are
explained previously, ICD contain a generator containing a
computer, battery, and wires called “leads” that go through
a vein into the heart. The leads stay in contact with the
heart muscle on one end, while the other end is connected
to the generator. The battery in the generator lasts an
average 5-8 years and must be replaced when it runs out
(National Institutes of Health). According to the
Portuguese Directorate-General of Health in Portugal in
the year 2012 were implanted 888 ICD (Direção Geral de
Saúde, 2013).
The aim of this work is the characterization of AIMD
to study the feasibility of their treatment.
2. Materials and methods
AIMD, previously disinfected by autoclaving, were
collected at several hospitals in the north of Portugal, and
then sent to Faculty of Science of the University of Porto
(FCUP) laboratory´s where they were identified and
weighed. The devices were opened in the physics
workshop with a handsaw and a lathe. After opening these
devices were examined macroscopically to find out the
best way to analyze them with more detail. The separation
into three major components appeared to be the best
option. The separation in smallest parts was done
physically with tweezers and the three main components
are: i) Exterior case and electrodes; ii) PCB’s; iii) Batteries
as showed in figure 1. All of the components were
identified and weighed individually, and were prepared to
be analyzed by Scanning Electron Microscopy (SEM).
For analyze of exterior case, the electrodes were
manually separated and the two components were
analyzed individually. A small piece of the exterior case
was selected and prepared with resin in order to be
analyzed in Materials Centre of the University of Porto
(CEMUP) by SEM technique.
In the workshop of physics, a chainsaw precision was
used to make transverse and longitudinal sections in the
polymer which coats the electrode.
The PCB’s were prepared with resin to ensure that all
conditions were satisfied to be analyzed by SEM
technique. The spots analyzed with SEM were previously
selected with careful observations in the magnifying glass
and the spots analyzed are showed in figure 2. SEM
technique does not allow the quantification of materials
Treatment proposal in AIMD
present in PCB, so two PCB from pacemakers were
selected and grinded in an agate mill to be subsequently
sent for an international laboratory (ALS Scandinavia AB)
with the aim of quantification the percentage of gold,
silver and platinum.
At this time the analysis of batteries was not performed
because these components are constituted by hazard
materials to public health.
1013
When compared with others type of PCB, these results
reveal to be very promising as the quantity of precious
metals present in this type of PCB is much higher than in
PCB used in other technologies such as laptops and
cellphones.
As previously mentioned, the batteries were not
analyzed because of their hazard components, but after
consulting factsheets about the principal’s manufacturers
(Medtronic and St. Jude Medical) it is possible to verify
that lithium iodine batteries are used in most recent
AIMD´s.
A survey about companies with processes to recycling
lithium iodine batteries show that these processes are
available in the market.
The results, even considering that the analytic methods
had focused in particular components, showed that AIMD
are constituted by a relevant quantity of metals with high
economic value, such as gold (Au) and silver (Ag), among
other metals with lowest economic value (titanium,
neodymium, bismuth, cooper, etc.).
Fig. 1. Exterior case, electrodes, PCB and batteries from Pacemaker (Left
to right).
Fig. 1. Cápsula, eletrodos, PCI e bateria de um Pacemaker (da esquerda
para a direita).
Fig. 3. Spectrum of point Z1 of PCB identified in figure 2 (SEM-EDS in
CEMUP).
Fig. 2. Identification of the points analyzed in the Printed Circuit Board.
Fig. 3. Espectro do ponto Z1 da PCI identificado na figura 2 (SEM-EDS
no CEMUP).
Fig. 2. Identificação dos pontos analisados na Placa de Circuito Impresso.
3. Results and discussion
The small portion of exterior case analyzed by SEM is
constituted by titanium (Ti) with very small inclusions of
cooper (Cu).
The results of SEM technique for the electrodes show
that they are constituted by a variety of metals with higher
incidence in iron (Fe) and manganese (Mn) and lowest
incidence in nickel (Ni), chromium (Cr) and others.
The results by SEM technique for PCB show that they
have a huge variety of metals in their constitution as
showed in figure 3 and 4 as well as in others types of
PCB´s (Table 1).
Quantitative analysis were only realized for 3 elements
(gold, silver and platinum), and the results showed the
presence of 5776 mg of gold (Au), 162 mg of silver (Ag)
and 81 mg of platinum (Pt) for each kg of PCB.
Fig. 4. Spectrum of point Z8 of PCB identified in figure 2 (SEM-EDS in
CEMUP).
Fig. 4. Espectro do ponto Z8 da PCI identificado na figura 2 (SEM-EDS
no CEMUP).
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R. Guimarães et al. / Comunicações Geológicas (2014) 101, Especial II, 1011-1014
Table 1. Typical composition of a Printed Circuit Board (PCB) of Waste
Electrical and Electronic Equipment (WEEE) and their respective
financial value (Goosey & Kellner, 2002).
the University of Porto and Alto Ave Hospital Centre in
special to Dr. Victor Sanfins.
Tabela 1. – Composição típica de uma Placa de Circuito Impresso (PCI)
de Resíduos de Equipamento Eléctrico e Electrónico (REEE) e o seu
respectivo valor económico (Goosey & Kellner, 2002).
Referências
4. Conclusions
The preliminary results allow us to consider that these
devices have conditions to be treated in a sustainable way,
since they were disinfected after explantation, with
particularly incidence in the recovery of the precious
metals presents. The survey, which was realized in small
scale, will continue with the purpose to determinate the
feasibility of the development this project in a larger scale.
Acknowledgments
The authors wish to acknowledge to Materials Centre of
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