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Assessment of Heavy Metals in Bottom Ashes from Medical Waste Incinerators and their Associated Health Risks in Dar es Salaam

Honest Anicetus, Josephat Saria, Samwel Manyele, Julius Mbuna


Bottom ashes originating from medical waste incineration contain heavy metals capable of

causing adverse effects to human beings and the environment. The main goal of this study

is to establish levels of heavy metals in bottom ashes from medical waste incinerators to

build a basis for the development of sustainable, safe, and efficient methods for healthcare

waste management. The study assessed the level of heavy metals in the bottom ashes of

thermally treated medical waste from six health care facilities in Dar es Salaam city,

Tanzania. Heavy metal concentrations were determined using Inductively Coupled Plasma -

Optical Emission Spectrometer (ICP-OES). While As, Cd and Hg were below detection limit,

Hg poses particular risk to public health since it may appear as vapour in the environment,

which can be inhaled by human beings. The average concentration of other heavy metals

followed the trend: Fe > Zn > Cr > Ni > Pb > Mn > Cu. All the metals investigated

exceeded the USEPA regulation on maximum permissible levels of heavy metals in good soil

quality, and hence classified as harmful and toxic. Therefore, there is a need to explore

environmentally friendly techniques for proper disposal of ash generated by incinerators,

or consider non-incineration techniques of medical waste management.


bottom ash, medical waste, incinerator, heavy metals

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Ahsan S. A., M. Lackovic, A. Katner & C. Palermo. 2009. Metal Fume Fever: A Review of the

Literature and Cases Reported to the Louisiana Poison Control Center. Journal of the Louisiana

State Medical Society 161(6):348–51.

Anamul, H., M. Tanvir & J. Rahman. 2012. Zinc and Nickel of Bottom Ash as a Potential Diffuse Pollutant

and their Application as “Fine Aggregate. Journal of Civil Engineering Research 2(6), 64–72. ASTM D6009-96. 2006. Standard Guide for Sampling Waste Piles.

Batterman, S. 2004. Findings on assessment of small-scale incinerators for healthcare waste, World

health organization, Geneva, 2004: 1–65. Available from:

_safety/publications/waste_management/en/Assessment_SSIspdf>, accessed on 20/09/2013.

Bernard, A.M., A. Vyskocil, J. Kriz, M. Kodl & R. Lauwerys. 1995. Renal effects of children Living in

the Vicinity of a Lead Smelter, Environmental Research 68: 91–95.

British Society for Ecological Medicine. 2008. The Health Effects of Waste Incinerators: 4th Report

of the British Society for Ecological Medicine, 2nd Edition. Available at http://www. bsem. Report_v3.pdf (Accessed on the 24th March, 2015).

Chang, C. Y., C. F. Wang, D. T. Mui, M. T. Chen & H. L. Chiang. 2008. Characteristics of Elements in

Waste Ashes from a Solid Waste Incinerator in Taiwan, Journal of Hazardous Materials 165:766–773.

Christophers, E, J. Brasch. 2003. Oral Lichenoid Reactions Associated with Amalgam: Improvement

after Amalgam Removal. The British journal of dermatology 148 (1): 70–6.

Colombo M.J. H. Juyoung, J. R. Reinfelder & N. Yee. 2013. Anaerobic Oxidation of Hg(0) and

Methylmercury Formation by Desulfovibrio Desulfuricans ND132, Geochimica et Cosmochimica

Acta 112: 166-177

De-Fre, R. & M. Wevers. 1998. Underestimation in Dioxin Inventories, Organohalogen Compounds


European Commission (2003. Project ENV.E.3/ETU/2000/0058, Heavy Metals in Waste http://ec. accessed on 20th May 2015.

Göthberg, A. & M. Greger (2006. Formation of Methyl Mercury in an Aquatic Macrophyte.

Chemosphere 65(11):2096 – 2105

Hickman. 1987. Cadmium and Lead in Bio-Medical Waste Incinerators. Master of Science Thesis,

University of California, Davis.

Hjelman, O. 1996a. Disposal Strategy for Municipal Solid Waste Incineration Residue. Journal of

Hazardous Materials 47:345–368.

Hjelmar, O. 1996b. Waste Management in Denmark, Waste Management 16: 389 – 394.

Jacob, J. O., T. B. Paiko, B. M. Yusuph & F. O. Falowo. 2009. Lead, Copper and Zinc Accumulation in

Soils and Vegetables of Urban Farms in Minna, Nigeria. International Journal of Chemical Sciences,


Knox, E. G. 2000. Childhood Cancers, Birthplaces, Incinerators and Landfill Sites. International Journal

of Epidemiology, 29:391–397.

Kumar, J. N. 2011. Solid Waste Generation in Gaborone Botswana. Potential for Resource Recovery,

MSc Thesis, University of Linkoping, Sweden.

Libert, L., A. Tursi, N. Costantino, L. Ferrara & G. Nuzzo. 1996. Optimization of Infectious Hospital

Waste Management in Italy: Part II. Waste Characterization by Origin. Waste Management &

Research, 14(5), 417–431.

Mahoney, D.B. & G. C. Moy. 2005. Food Borne Hazards of Particular Concern to Children. In:

Pronczuk de Garbino J. Editor. Children’s Health and the Environment, a Global Perspective: A

Resource Manual for the Health Sector.

Manyele, S. V. & H. Anicetus. 2006. Management of Medical Waste in Tanzanian Hospitals. Tanzania

Health Research Bulletin 8(3):177–82.

Manyele, S. V. & C. M. Mujuni. 2010. Current Status of Sharps Waste Management in the Lowerlevel

Health Facilities in Tanzania. Tanzania Journal of Health Research 12(4): 257–264.

Oliver, M. A. 1997. Soil and Human Health: A Review. European Journal of Soil Science 48, 573–592.

Onibokun, A.G. 1999. Managing the Monsters: Urban Waste and Governance in Africa. International

Development Research Centre, Ottawa.

Pirkle, J. L., R.B. Kaufman, D. J. Brody, T. Hickman, E. W. Gunter & D. C. Paschal. 1998. Exposure of the

U.S. Population to Lead, 1991–1994. Environmental Health Perspectives 106(11): 745–750.

Prochazkova, J., I. Sterzl, H. Kucerova, J. Bartova & V. D. Stejskal. 2004. The Beneficial Effect of Amalgam

Replacement on Health in Patients with Autoimmunity. Neuro Endocrinology Letters 25 (3): 211–8.

Racho, P. 2002. A Study of Heavy Metals in Bottom Ash from Medical Waste Incinerator in Nakhonr

Atchasima Municipality. Master in Environmental Engineering, Suranaree University of


Reinhardt, P. A. & J. G. Gordon. 1991. Infectious and Medical Waste Management, Chelsea,

Michigan: Lewis Publishers.

Scuhmacher, M., M. Meneses, S. Granero, J. M. Llobet & J. L. Domingo. 1997. Trace Element

Pollution of Soils Collected near a Municipal Solid Waste Incinerator: Human Health Risk.

Bulletin of Environmental Contamination and Toxicology 59: 861–867.

Stewart-Pinkham, S. M. 1989. The Effect of Ambient Cadmium air Pollution on the Hair Mineral

Content of Children. The Science of the Total Environment 78:289–96.

Takata T. 2003. Survey on the Health Effects of Chronic Exposure to Dioxins and its Accumulation

on Workers of a Municipal Solid Waste Incinerator, Rural Part of Osaka Prefecture & the Results

of Extended Survey Afterwards. Industrial Health 41-3:189–96.

TZS. 860: 2005 Municipal and Industrial Wastewaters-General Tolerance Limits for Municipal and

Industrial Wastewaters.

USEPA. 2007. Source Reduction, Retrived from

page=2 (12th May 2015).

World Health Organization (WHO). 1998. WHO Experts Re-evaluate Health Risks from Dioxins,


Zang, F. S., S. I. Yamasaki & M. Nanzyo. 2001. Application of Waste Ashes to Agricultural Land-effect

of Incineration Temperature on Chemical Characteristics. The Science of the Total Environment

: 205–215.


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