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Year : 2017  |  Volume : 24  |  Issue : 1  |  Page : 20-24

An investigation into the radiological waste management of selected centers in Kano metropolis, Nigeria

1 Department of Medical Radiography, Bayero University Kano, Aminu Kano Teaching Hospital, Kano, Nigeria
2 Department of Medical Radiography, College of Medical Sciences, University of Maiduguri, Borno State, Kano, Nigeria
3 Department of Radiology, Aminu Teaching Hospital/Bayero University, Kano, Nigeria

Date of Web Publication11-Jan-2017

Correspondence Address:
Mohammed Sidi
Department of Radiology, Aminu Kano Teaching Hospital, Kano
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1115-3474.198079

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Background: There is a need for every radiological facility to have an effective method of waste management for environmental protection and cost-effectiveness. Most of the waste produced by the facilities could be reclaimed and recycled for medical and industrial purposes. Study Aim: This study aims at investigating radiological waste management in some selected centers in Kano metropolis. Materials and Methods: The study design is descriptive in nature. Using purposive sampling method, eleven centers were selected. These are the hospitals and private centers that use automatic, manual, or both processing methods in their units. An unstructured interview was conducted with the technician in-charge of the various processor units. The audio-taped interview was converted to text notes for content analysis. The data were analyzed using standardized, open-ended content approach. Samples of spent solutions were analyzed for silver concentration using quantitative analysis. Results: Film processing units of radiological facilities in Kano metropolis drained their spent radiographic films processing solutions directly into general drainage system without being treated. The waste radiographic films and X-ray film packages were being discarded into dustbins. Quantitative analysis shows a high concentration of silver in the spent solutions; the average concentration of silver in spent developer, rinse, fixer, and wash solutions was found to be 1.4 mg/L, 0.9 mg/L, 5.2 g/L and 2.8 mg/L, respectively. Conclusion: There is no systematic system of waste disposal in Kano metropolis of Nigeria.

Keywords: Investigation; Kano metropolis; radiological wastes management

How to cite this article:
Sidi M, Nwobi C, Dambatta AH. An investigation into the radiological waste management of selected centers in Kano metropolis, Nigeria. West Afr J Radiol 2017;24:20-4

How to cite this URL:
Sidi M, Nwobi C, Dambatta AH. An investigation into the radiological waste management of selected centers in Kano metropolis, Nigeria. West Afr J Radiol [serial online] 2017 [cited 2022 Aug 12];24:20-4. Available from: https://www.wajradiology.org/text.asp?2017/24/1/20/198079

  Introduction Top

There is a need for every radiological facility to have an effective way of waste management for environmental protection and cost-effectiveness. Despite the current technological advancements in computed and digital radiography, the manual, auto, or both radiographic film processing methods are still in use in most of the radiological facilities in Kano metropolis. Radiographic film processing is the main source of waste in the radiological facility. The waste stream associated with image processing consists of scrap film, spoiled chemicals, and wastewater containing chemicals and silver. In the course of radiographic film processing using the manual or automatic processing method, excess silver from the emulsion layer is released into the fixer solution with the silver concentration most frequently exceeding 5 g/L. [1] About 4.5 g/L of silver can also be recovered from wasted radiographic films. [2] Silver solution should be regulated as an environmental waste and discharged according to the approved city limits for silver. According to the European decision 2001 \ 118 \ EC (EEL, 47 \\ 2001), establishing the European wastes and hazardous wastes, imaging wastes are regarded as potentially hazardous wastes. [1] The adverse effects of chronic exposure to silver are permanent bluish-gray discoloration of the skin (argyria) or eyes (argyrosis). Most cases of argyria and argyrosis have resulted primarily from exposure to the soluble forms of silver. Besides argyria and argyrosis, exposure to soluble silver compounds may produce other toxic effects, including liver and kidney damage, irritation of the eyes, skin, respiratory, and intestinal tract, and changes in blood cells. [3]

The first reason why silver should be reclaimed from the spent film processing solution is because of its hazardous effect. Once silver is reclaimed from the solution, it is exempted from all hazardous waste regulations. [1] The second reason for recovering silver from liquid photographic effluents is that it is a valuable commodity, and since there are effluents containing sufficient amount of silver, a cost-effective recovery could be implemented. Various methods of recovering silver (e.g., metallic replacement, electrolytic recovery) and a number of market equipment are available. Moreover, in some parts of the world, there is an organization responsible for collecting the effluents and recovering the silver from it. After selling the silver recovered from imaging wastes, the organization is obliged to credit 75% of the profit to the health unit and retain the remaining 25%. [1] A study revealed that the amount of silver recovered per year from ten hospitals amounted to 140,527 U.S. $ (about 116500 euros), part of which returned as income to the state. [1]

Through the author clinical experience in one of the radiological facilities in Kano metropolis, silver solution is being discharged directly into the drainage system. This has a potential for environmental pollution and economic loss to the facility.

  Materials and Methods Top

The aim of the study is to determine the practice of radiological waste management of selected centers in Kano metropolis. The study design is descriptive in nature. The study was conducted conducted in Kano metropolitan area from January 2016 to March 2016. Using nonprobability purposive sampling method, study centers were selected; these include two federal government hospitals, seven state government hospitals, and two private radio-diagnostic centers, identified with numbers 1-11. These were centers with functioning X-ray equipment using automatic, manual, or both processing methods for radiographic film processing. All the hospitals and private radio-diagnostic centers without functioning X-ray equipment or with a functioning X-ray equipment but use either computed radiography or digital radiography were excluded from the study. Center 1 had three processing units, two automatic and one manual; two manual processing units were surveyed each in Centers 2 and 3. The remaining centers each had one manual processing unit. In every center, the staff in charge of the darkroom was selected for the interview; it was assumed that this individual would possess the most accurate information regarding the centers' waste management system. Interview questions were open-ended. The informants were asked to answer questions to the best of their understanding. Informed consent was obtained from each informant. The communications between the researchers and informants were audio-taped. Questions asked during the interview include age, cadre, and working experience; the number of films used per month, volume of fixer and developer solutions used per month, how the rejected films were discarded, and how the spent fixer, developer, wash and rinse solutions were disposed of. The recorded information was then transcribed to text notes for analysis. A standardized, open-ended content analysis approach was used to analyze the obtained data.

In every processing unit, 2 ml each of fixer, developer, and washer solutions was collected and taken to the laboratory for analysis of silver concentration. For centers operating the manual processing system, sample of the rinse solution was also analyzed. The amount and cost of silver that could have been recovered from every processing unit were calculated from the concentration of the silver in fixer solution per volume of the fixer solution used in each processing unit. The fixer solution was used for the analysis; it is recognized to contain the highest concentration of silver among the solutions.

  Results Top

A total of 15 darkroom attendants were interviewed from the government hospitals and private radio-diagnostic centers. They were males with a mean age of 42 years and standard deviation of 7.49 years. Their work experience ranged from 2 years to 23 years. The distribution of processing units is shown in [Table 1]. Center 1 generated 430 and 225 L of spent developer and fixer solutions per month from the three processing units. The silver concentrations in developer, rinse, fixer, and wash of processing unit A were 1.1 mg/L, 0.8 mg/L, 6.2, g/L and 3.0 mg/L. Units B and C were automatic processors and therefore had no rinse solutions. The concentrations were 0.8 mg/L, 5.0 g/L, and 1.8 mg/L for unit B and 0.6 mg/L, 5.0 g/L, and 1.5 mg/L for unit C. The amount of silver which might have been recovered from fixer solutions in Center A was 13.86 kg per year and with the current price of silver of 474 USD per kg. The management has been losing 6570 USD per year from the spent fixer solution. Center 2 produced 120 L each of developer and fixer solutions per month. The silver concentration of the developer, rinse, fixer, and wash in processing unit A were 0.9 mg/L, 1.4 mg/L, 5.3 g/L, and 2.6 mg/Ll and of the processing unit B were 0.6 mg/L, 0.8 mg/L, 4.9 g/L, and 2.4 mg/L. The quantity of silver lost through the fixer solution in Center 2 was 7.440 kg per year which cost 3527 USD per year. Centers 3-9 which were hospitals from the state government generate 1190 L of developer solution and 270 L of fixer solution. The mean silver concentrations of the spent solutions in the seven hospitals were 1.9 mg/L, 1.0 mg/L, 5.1 g/L, and 3.4 mg/L. The hospitals lost 17.63 kg of silver per year; hence, the state health management has been losing 8356.62 USD per annum. Center 10 generated 10 L each per month of developer and fixer solutions and the concentrations of the spent were 0.8 mg/L, 0.4 mg/L, 5 g/L, and 1.4 mg/L. The center lost 0.60 kg per year which cost 284 USD. While Center 11 produced 10 L each of developer and fixer solutions per month and the concentrations of silver were 1.0 mg/L, 0.8 mg/L 5.5 g/L, and 1.9 mg/L. It lost 0.66 kg per year with an estimated cost of 313 USD. In the entire selected centers, the spent radiographic film processing solution was drained into general drainage system without any treatment and wasted X-ray films were discarded into the dustbins.
Table 1: How spent radiographic film processing solutions are being managed in Kano metropolis

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  Discussion Top

The findings of the current study as shown in [Table 1] show that all the radiographic processor units in the selected centers drained the fixer, developer, rinse, and wash solutions directly into drainage system in Kano metropolis. All the spent processing solutions produced from the processor units in Kano metropolis contained silver exceeding internationally approved limits for direct discharge into the drainage system as shown by quantitative analysis of the solutions in [Table 2]. Once the concentration of silver in spent radiographic film solution exceeds 0.5 mg/L, it should not be discharged directly into the drainage system. [4] Therefore, radiological facilities in Kano metropolis are sources of significant environmental pollution by discharging these solutions into the drainage system without treatment. Discharging hazardous chemicals to the general drainage system will affect the environment and the members of the public more, especially those in direct contact with the chemicals without protective instruments. In the entire centers, the waste radiographic films were discarded into dustbin as shown in [Table I], finally ending up at the general refuse site of the hospitals and centers. The solid silver in the waste radiographic films is a pollutant to the environment. The management loses a lot of money from the silver and plastics that might have been recovered from the waste radiographic films. The current study is in accordance with the findings of Sanida et al., [1] which show that the management of radiological facilities lose a lot of money due to poor management of radiological wastes. Their findings show significant contribution of radiological facilities to environmental pollution because the spent radiographic film processing solutions are drained into general drainage system without any treatment. The findings of the current study went contrary to the study conducted by Amorim and Bauer, [5] which shows that only 43% affirmed that they threw the solution directly through the sink, 36% diluted the fixer in water and threw it into the sink, 14% used a specialized company to discard it, and 7% used other means. The developer was discarded as follows: 42% threw it down the sink, 36% diluted it in water before throwing it into the sink, 13% used a specialized company to discard it, and 9% used other ways. With respect to the disposal of radiographic films, 51% threw them into the trash and 49% used a specialized disposal company. Another study conducted by Grigoletto et al. [6] shows that 16.66% of the health-care centers discharge their developer solution directly into the drainage system, fixer by 8.33%, and film washing water by 75% of the centers. This was not in accordance with the current study which revealed that all the selected centers drained their spent solutions directly into the drainage system. The findings of the study conducted by Carlson [7] are in agreement with the current study which observed that chemical residues such as developer, fixer solutions, and xylene leftovers were inappropriately stored in the place where they were generated and were later taken into the basement of the building, where they were left under unsafe conditions, in an unventilated area, without containment means, and over permeable floor.
Table 2: Silver concentration in spent radiographic film processing solutions

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For the spent developer solution, image service or technician should wear personal protection equipment, such as glasses and gloves. The solution should then be diluted with equal volume of water and drained into the drainage system. [8] Drain service contract should be coordinated to ensure drains are regularly cleaned out twice per year. [8]

For the spent fixer solution, the image service or technician using personal protection equipment should collect the used solution in a plastic container, and the container should have a tight-fitting cap that remains closed at all times, except when adding the fixer and be well labeled. When the container is 90% filled, it should be carried away from the processing unit by a trained technician for on-site or off-site silver recovery.

The plastic base and its content of silver must be stored in properly labeled secondary containers which will finally be carried away by appropriately-trained technicians.

The internationally accepted method of silver removal from the fixer solution is by either electrolysis or metallic replacement. If the facility is large, it should have an on-site silver recovery unit. The unit uses an instrument to remove the dissolved silver from the fixer solution. Once the silver has been removed, the solution is no more hazardous and can be drained into the general drainage system. If the facility does not have on-site silver recovery unit, it is mandatory to look for off-site silver recovery unit that will collect the fixer and recover silver from it. This can either be a company or another facility that has a silver recovery unit.

  Conclusion Top

Radiological facilities in Kano metropolis contribute to environmental pollution through a lack of standardized and poor methods of radiological waste management while losing significant source of potential economic benefit from silver recovery.


  1. The managements of federal and state government hospitals should endeavor to have silver recovery units
  2. They should also have a mean of reclaiming and recycling the important components of the discarded X-ray films
  3. The solid lead from X-ray films packages should be separated for recycling by appropriate authorities
  4. Technicians' in-charge of the processing units should receive training on proper disposal of spent solutions.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Sanida G, Karagiannidis A, Moussiopoulos N, Vartzopoulos D. Medical Imaging Wastes from Health Units: Field Survey and Treatment Options - A Case Study; 2005. Available from: https://www.google.com/search?q=+G.+Sanida1,+A.+Karagiannidis2,+N.+Moussiopoulos2,+D.+Vartzopoulos1 and ie=utf-8 and oe=utf-8 and rls=org.mozilla: En-US: Official&client=firefox-beta&gfe_rd=cr and ei=-N2rVuuWLu3U8gfmjJCQCw. [Last cited on 2016 Jan 10].  Back to cited text no. 1
Marinkoviæ J, Koraæ M, Kamberoviæ Ž, Matiæ I. Recycling of Silver from Exposed X-Ray Films; 2006. Available from: http://www.web.tuke.sk/hf-knkaso/content/veda/konferencie/waste/marinkovic.pdf. [Last cited on 2016 Jan 08].  Back to cited text no. 2
Drake PL, Hazelwood K. Exposure-Related Health Effects of Silver and Silver Compounds: A Review; 2014. Available from: http://www.ExposureRelated%20Health%20Effects%20of%20Silver%20and%20Silver%20Compounds%20%20A%20Review.ht. [Last cited on 2016 Jan 12].  Back to cited text no. 3
Aktas S, Morcali MH, Yucel O. Silver Recovery from Waste Radiographic Films by Cementation and Reduction; 2010. Available from: https://www.researchgate.net/publication/233650668. [Last cited on 2016 Jan 03].  Back to cited text no. 4
New York University, College of Dentistry, Policy on the Management of Wastes Generated from X-ray Procedures and Film Processing; 2005. Available from: https://www.nyu.edu/life/safety-health-wellness/be-safe/environmental-health-and-safety/waste-disposal/dental-clinic-wastes.html. [Last cited on 2016 Feb 16].  Back to cited text no. 5
Amorim JM, Bauer J. Evaluation of Radiologic Waste Management in Dental Offices and Radiology Clinics of Sao Luis, MA; 2012. Available from: http://www.univille.edu.br/account/odonto/ VirtualDisk.html?action=readFile and file=v9n3a05.pdf and current=/RSBO_-_v. 9_-_n. 03-_julho-setembro_2012. [Last cited 2016 Jun 04].  Back to cited text no. 6
UC Scan Diego. Managing Photo and X-ray Processor Equipment; 2015. Available from: http://www.blink.ucsd.edu/safety/research-lab/hazardous-waste/photo.html. [Last cited 2016 Jun 12].  Back to cited text no. 7
JC, dos Santos CB, Albertini LB,Takayanagui AM,.Radiographic Processing Effluents Management Status in Healthcare Centers; 2011. Available from: http://www.scielo.br/ scielo.php?pid=S010039842011000500008 and script=sci_arttext and tlng=en. [Last accessed on 2016 Jun 09].  Back to cited text no. 8


  [Table 1], [Table 2]


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