The microbiological hazards of municipal and clinical wastes

Seroprevalence of hepatitis B and C viruses among waste handlers in Ethiopia: A systematic review and meta-analysis

Objective

Hepatitis B virus and hepatitis C virus are the leading causes of global liver-related morbidity and mortality. Waste handlers are one of the high-risk groups for hepatitis B virus and hepatitis C virus acquisition. Thus, the aim of this study was to assess the pooled prevalence of hepatitis B virus and hepatitis C virus among waste handlers in Ethiopia.

Methods

Articles were extensively searched in bibliographic databases and gray literature using entry terms or phrases. Studies meeting eligibility criteria were extracted in MS Excel and exported to STATA version 14 software for statistical analysis. A random-effects model was used to compute the pooled magnitude of hepatitis B virus and hepatitis C virus. Heterogeneity was quantified by using the I2 value. Publication bias was assessed using a funnel plot and Egger's test. Sensitivity analysis was performed to assess the impact of a single study on pooled effect size.

Result

Of the 116 studies identified, 8 studies were selected for meta-analysis. All studies reported hepatitis B virus, while 5 studies reported hepatitis C virus infection among waste handlers. The overall pooled prevalence of hepatitis B virus and hepatitis C virus infection among waste handlers in Ethiopia was 5.07% (2.0-8.15) and 1.46% (0.52-2.4), respectively. Moreover, the pooled prevalence of lifetime hepatitis B virus exposure among Ethiopian waste handlers was 33.98% (95% CI: 21.24-46.72). Hepatitis B virus and hepatitis C virus infection were not statistically associated with the type of waste handlers, that is, there was no difference between medical and nonmedical waste handlers.

PROSPERO registration

CRD42023398686.

Conclusion

The pooled prevalence of hepatitis B virus and hepatitis C virus infection among waste handlers in Ethiopia was intermediate and moderate, respectively. This showed that there is a strong need to scale up preventive efforts and strategic policy directions to limit the spread of these viruses. Moreover, we also conclude that handling healthcare and domestic waste is associated with a similar risk of hepatitis B virus and hepatitis C virus infection.

Knowledge, perceptions and practices on healthcare waste management and associated occupational health hazards among healthcare professionals in the Colombo District, Sri Lanka: a cross-sectional study

Background

Proper Healthcare Waste (HW) management is directly influenced by the knowledge and attitudes of Healthcare Professionals (HCP). However, studies that characterize the knowledge and practices of HCP on HW management are limited in Sri Lanka. This study was conducted to characterize the knowledge, perceptions and practices of HCP on the management of HW and to determine the risk factors influencing HW related occupational health hazards in the Colombo District of Sri Lanka.

Methods

A total of 407 HCP were recruited as the study population from selected hospitals in the Colombo District. Information on socio-demographic factors, knowledge, attitudes and practices on HW management were gathered using an interviewer-administrated questionnaire. The Binary Logistic Regression (BLR) was used to determine the socio-economic risk factors associated with the occurrence of HW related health issues among the respondents.

Results

The majority of respondents were characterized with a high knowledge level (76.9%) and positive attitudes (53.8%) on HW management. Incineration (82.6%) was recognized as the most widely used HW treatment method. Personal Protective Equipment (PPE) was used at a satisfactory level (85.5%), while liquid waste treatment was limited (57.5%). The occupational designation, level of training received in HW management, professional experience, vaccination status for tetanus, degree of knowledge and attitudes on HW management were recognized as significant risk factors (p < 0.05) associated with the occurrence of HW related occupational hazards.

Conclusion

Even though, the treatment of HW was satisfactory, strengthening the existing mechanisms for monitoring of HW management, provisioning more resources and organizing training and awareness programmes on HW management for HCP are recommended.

Elucidating the role of environmental management of forests, air quality, solid waste and wastewater on the dissemination of SARS-CoV-2

The increasing frequency of zoonotic diseases is amongst several catastrophic repercussions of inadequate environmental management. Emergence, prevalence, and lethality of zoonotic diseases is intrinsically linked to environmental management which are currently at a destructive level globally. The effects of these links are complicated and interdependent, creating an urgent need of elucidating the role of environmental mismanagement to improve our resilience to future pandemics. This review focused on the pertinent role of forests, outdoor air, indoor air, solid waste and wastewater management in COVID-19 dissemination to analyze the opportunities prevailing to control infectious diseases considering relevant data from previous disease outbreaks. Global forest management is currently detrimental and hotspots of forest fragmentation have demonstrated to result in zoonotic disease emergences. Deforestation is reported to increase susceptibility to COVID-19 due to wildfire induced pollution and loss of forest ecosystem services. Detection of SARS-CoV-2 like viruses in multiple animal species also point to the impacts of biodiversity loss and forest fragmentation in relation to COVID-19. Available literature on air quality and COVID-19 have provided insights into the potential of air pollutants acting as plausible virus carrier and aggravating immune responses and expression of ACE2 receptors. SARS-CoV-2 is detected in outdoor air, indoor air, solid waste, wastewater and shown to prevail on solid surfaces and aerosols for prolonged hours. Furthermore, lack of protection measures and safe disposal options in waste management are evoking concerns especially in underdeveloped countries due to high infectivity of SARS-CoV-2. Inadequate legal framework and non-adherence to environmental regulations were observed to aggravate the postulated risks and vulnerability to future waves of pandemics. Our understanding underlines the urgent need to reinforce the fragile status of global environmental management systems through the development of strict legislative frameworks and enforcement by providing institutional, financial and technical supports.

Characteristics of microbial aerosol particles dispersed downwind from rural sanitation facilities: Size distribution, source tracking and exposure risk

Bioaerosols containing pathogens released from waste and wastewater treatment facilities pose potential health risks to workers on-site and residents downwind. In this study, sampling sites were set up at rural garbage stations (GS-1 and GS-2) and sewage treatment station (STS) to investigate the emission and diffusion characteristics of bioaerosols. High-throughput sequencing was utilized to assay the intestinal bacteria population, while the health risks associated with bioaerosols exposure were estimated based on average daily dose rates (DD). Traceability analysis was used to determine the percentages of intestinal bacteria from GS-1, GS-2 and STS. The recorded emission levels of bioaerosols in the air surrounding GS-1, GS-2, and STS were 5053, 6299, and 4795 CFU/m³, containing 1599, 2244, and 2233 CFU/m³ of intestinal bacteria, respectively. Most of the bioaerosols were coarse particles with size larger than 4.7 μm. Methylobacterium, Rhizobium, Pseudomonas, Enterobacteriaceae, and Brucella presented in the air were originally in rural waste and wastewater. STS and GS-2 were potential sources of intestinal bacteria. With increasing distance from the sources, the concentration of bioaerosols decreased gradually. On-site workers and residents were predominantly affected by bioaerosols through inhalation. The exposure risks via inhalation and skin contact for children were much higher than that for adults. The purpose of this study was to provide preliminary data for bioaerosols control and their risks reduction released from rural sanitation facilities.

Scavenger birds exploiting rubbish dumps: Pathogens at the gates

Different bacteria are present in rubbish dumps used as food resources by various bird species. Birds may be good indicators of the presence of zoonotic diseases in these sites since they can be infected with zoonotic pathogens by foraging on organic waste, and can also act as carriers. We studied if foraging in rubbish dumps increases the occurrence of Salmonella spp. and Chlamydia psittaci in American black vultures (Coragyps atratus, hereafter black vultures) from northwest Patagonia. We compared these pathogens isolated from or detected in cloacae and oropharynx swabs in two different groups of black vultures: individuals trapped in (a) the Patagonian wild steppe and (b) in a rubbish dump. We found that black vultures are colonized by Salmonella spp. (particularly Salmonella enterica serotypes Typhi, Paratyphi A, Salmonella enterica subsp. arizonae) and Chlamydia psittaci. Interestingly, there were differences in the prevalence of Salmonella spp., especially Salmonella Typhi, between individuals foraging in the rubbish dump and the steppe, but not in the prevalence of Chlamydia psittaci. The pathogens isolated from black vultures may impact their health status but could also have health impacts in other bird species and even humans. In fact, Salmonella Typhi can cause severe disease in humans leading to death. Our results are globally relevant given that bacterial infections from rubbish dumps may affect different species exploiting these sites around the world. There is a need to better control pathogens in rubbish dumps to avoid the risk of infecting wildlife, which could act as potential dispersers and reservoirs of these pathogens.

Municipal landfill sites as sources of microorganisms potentially pathogenic to humans

The present research was aimed at assessing the quality of air and soil on the premises and in the vicinity of the municipal landfill sites in Toruń with regard to the presence of pathogenic bacteria, potentially dangerous to humans. Air samples (the impaction method using a MAS-100 impactor) and soil samples were collected from seven sampling sites including the operating and closed landfill cells, sampling sites located near leachate ponds, and sampling sites located outside the above premises. The research also involved assessing microbial air contamination in three indoor spaces on the premises of the landfill sites. Microbial tests involved the determination of the number of culturable mesophilic, mannitol-positive, and α- and β-hemolytic bacteria in the air, determination of the number of coliform bacteria, spore-forming Clostridium perfringens in soil, and the presence of Salmonella in soil. The results indicate that bioaerosol emitted by this municipal facility is the source of hemolytic bacteria (≤ 300 CFU m(-3) of air), as well as of pathogenic bacteria (Pseudomonas aeruginosa and Bacillus subtilis). The highest risk of exposure to biological agents was determined in the sorting facility. Over sixty percent of air samples in this sampling site presented high pollution degree with mesophilic bacteria (500-2000 CFU m(-3) of air) and over one fourth of air samples presented very high pollution degree (>2000 CFU m(-3) of air). Indoor air in other rooms was considered highly/moderately contaminated (100-2000 CFU m(-3) of air). The highest risk related to the presence of Salmonella, Clostridium perfringens, and coliform bacteria in soil was determined at the operating landfill cell and near the leachate pond of the closed landfill cell. At the operating landfill cell the total coli ranged from 4-1226 MPN g(-1) of dry mass of soil and Clostridium perfringens ranged from <LOD-1604 CFU g(-1) of dry mass of soil. The results question the strategy of municipal landfill sites in densely populated areas, and emphasize the need for regular monitoring of microbiological tests in their vicinity as well as for control strategies in order to protect workers at landfill sites. The results of the study should be used for future decisions on the location of municipal landfill sites and suggest the need for better environmental control technologies in the sites that are already functioning.

Exposure to aerosolized bacteria and fungi among collectors of commercial, mixed residential, recyclable and compostable waste

Biological hazards associated with the collection of solid and compostable waste have not been well characterized in North America. This is an issue because workers who handle such materials may be exposed to bioaerosols (airborne bacteria and fungi) and dusts resulting in infections or allergic diseases. We conducted a personal sampling campaign for culturable bacteria and fungi in the breathing zones of waste collectors in a variety of typical work settings (scenarios) in the province of Quebec, Canada. Total culturable bacterial and fungal counts were analyzed and compared to ambient environmental levels (background) to determine the degree of incremental exposure among workers. In several scenarios, worker exposure counts were significantly (p < or = 0.05) higher than ambient levels measured upwind, with the highest personal exposures to bacteria observed for urban compostable waste collectors (median = 50,300 Colony Forming Units/m(3) of air (CFU/m(3))). On the other hand, fungal counts collected on an every-other-week cycle were highest among a group of rural compostable waste collectors (median = 101,700 CFU/m(3)). Similar exposures to culturable bacteria and fungi have been reported in European workers who showed such adverse health effects as nausea, diarrhea, upper respiratory tract irritation, and allergy. Therefore, it may be necessary to modify certain work practices in order to minimize exposure. Recommendations include automation of waste and compost collection, use of personal protective equipment including goggles, gloves, and disposable masks, and meticulous personal hygiene.

Microbial air quality in offices at municipal landfills

The purpose of this study was to evaluate the influence of two municipal landfills on the microbiological air quality in offices on landfill sites. The evaluation was based on the concentration levels of airborne bacteria and fungi and the identification of isolated strains. Air samples were collected with a six-stage Andersen impactor. The concentrations of bacterial aerosol ranged from 1.0 x 10(3) to 7.2 x 10(4) colony forming units (CFU)/m(3) indoors, and from 7.0 x 10 to 4.0 x 10(4) CFU/m(3) outdoors. The corresponding fungal aerosol ranges were from 2.3 x 10(2) to 7.3 x 10(3) CFU/m(3) indoors and from 2.0 x 10(2) to 1.2 x 10(4) CFU/m(3) outdoors. The concentration levels were affected by the season of the year. The study showed that both indoor and outdoor air were heavily contaminated with bacteria and fungi. The proximity of the unpaved transport route and the weighing of refuse loads contributed to the increase of bacterial and fungal aerosol concentrations significantly. The air in the offices was characterized not only by elevated concentrations of bacteria and fungi but also by high frequencies of gram-negative bacteria, along with fungal species characteristic of landfills. The quantitative and qualitative changes in the composition of the bacterial and fungal aerosol posed a possible health risk to office workers at municipal waste landfill sites.

Hospital waste management in Brazil: a case study

The evaluation of the current definition, classification and quantification of hospital waste being carried out by hospitals in different countries is extremely important to avoid improper waste management practices. In this work, the waste management from a 400-bed Brazilian hospital which generates about 386 kg per day of hospital waste was studied. The generation rate of just over one kg per bed per day was considered small, although more than 50% of the waste from non-isolation wards consisted of food waste. It was also interesting to note that the highest generation rate per patient per day was found in private rooms and the lowest rate in the public ones. The waste practices used in this hospital are discussed in terms of current Brazilian legislation.

[Public and occupational health aspects related to municipal solid waste management]

Based on a literature review, the paper calls attention to public and occupational health problems related to poor municipal solid waste management resulting from a development model that views environmental protection, public health, and workers' health as secondary issues. The authors emphasize the need for research to support a new waste management model highlighting the importance of environmental preservation and protection of human health, in addition to suggesting measures to achieve such goals. The discussion aims to incorporate solid waste management into the public health agenda.

Bacteriological validation of a new apparatus for disinfection of hospital waste at the point of disposal

OBJECTIVES

To evaluate the ability of a new apparatus (Dipsys 25, Société SGN, Bagnols sur Cèze, France) to disinfect biomedical waste, including both potentially infectious agents and the normal saprophytic flora of the waste.

METHODS

Disinfection was assessed using standard methods (reference strains were fixed on reference carriers according to the French AFNOR methods) and nonstandard assays. Assays in conditions of hospital use, evaluations of bacterial survival during storage, sporicidal effect, and spore survival during storage were performed in parallel. Finally, bactericidal effect in extreme conditions (association of high contamination and high bacterial protection conditions) was tested with normal fecal flora. Bacterial counts were performed after treatment by the apparatus and without treatment (controls). All tests were carried out in triplicate.

RESULTS

In all treated carriers, a bacterial population decrease of at least 5 log10 was obtained. Assays performed in hospital-use conditions did not show any bacterial growth. Concerning the evaluation of sporicidal effect and spore revival during conservation, a minimum reduction of 5 log10 was observed in all assays performed, without survival. Finally, concerning assays in extreme conditions, the decrease of bacterial population was between 5 log10 and 10 log10 for vegetative anaerobes of normal fecal flora.

CONCLUSION

Under our study conditions, the study apparatus reduced the tested microbial populations by a minimal factor of 5 log10. The main advantage of the apparatus is the opportunity to treat contaminated waste inside hospital wards, at the point of initial collection, without pulverization, by nonspecialized staff.

Microbiological aspects of clinical waste

It is a requirement that hospitals and other areas that generate clinical waste must comply with good practice and legislation regarding its disposal. To meet the stringent European emission standards enforced in October 1995, there is a need to find an alternative to local incineration for dealing with clinical waste. The options included technologies such as gasification, steam sterilization or heat disinfection which can be used to process certain categories of clinical waste prior to landfill--all have advantages and disadvantages. Segregation of clinical and domestic wastes in healthcare settings is important to avoid accidents and litigation and to contain costs. Evidence that most clinical waste (other than perhaps waste from patients with certain infections and sharps) is a significant hazard to the public is lacking. More still needs to be done in the area of clinical waste management to assess the real risks and hazards of this waste.

Resíduos sólidos e lixo hospitalar: uma discussão ética

O presente artigo trata da questão dos resíduos sólidos, discutindo os problemas decorrentes de um modo de ser e de agir, resultante das relações entre Primeiro Mundo e Terceiro Mundo e as perspectivas para o meio ambiente se não ocorrer uma ética renovada de solidariedade entre seres humanos e de respeito à vida. A partir dessa visão mais geral, o artigo trata, então, das questões específicas dos resíduos hospitalares, as interferências e imposições da "cultura" de Primeiro Mundo nos sistemas de manuseio, tratamento e disposição dos resíduos, no Brasil, procurando problematizar a questão da periculosidade (ou não) de tais resíduos.