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PubMedDate not supplied

Procedures for destruction of patulin in laboratory wastes.

Patulin is immunosuppressive and there is limited evidence of its carcinogenicity in experimental animals. The International Agency for Research on Cancer (IARC) initiated a programme for the development of degradation techniques for the commonly investigated mycotoxins. As a part of this programme, the following techniques were tested for the degradation of patulin: treatment with ammonia, treatment with ascorbic acid, and treatment with potassium permanganate in acidic or in alkaline conditions. Patulin analysis was performed by using HPLC with UV detection. Mutagenic activity of degradation residues was tested by in Salmonella typhimurium strains TA 97a, TA 98, TA 100, and TA 102. Complete disappearance of patulin was not achieved after 92 h of treatment with ascorbic acid. All the other methods tested led to complete removal of the molecule. However, the technique using potassium permanganate in acidic conditions produced residues which were mutagenic without activation to Salmonella typhimurium strains TA 100 and TA 102, which was attributed later to Mn2+. The two other techniques gave satisfactory results and were selected for further validation studies.

Ammonia↗
PubMed2006

Management of dead bodies as a component of psychosocial interventions after the tsunami: a view from Sri Lanka.

Even if predicted, disasters may not be completely averted due to reasons beyond human control. There is always likely to be a degree of loss, human as well as material. Therefore, the correct strategy is to limit the damage and minimize the harm. Such damage control exercises should be mindful about the psychological costs of the disaster. Identification of dead bodies and the missing, as well as providing a dignified burial, is a crucial part of the overall management of a disaster. It will alleviate the long-term psychological as well as legal consequences. Hence, a comprehensive forensic service including modern genetic capabilities is a must for disaster response. Development of a comprehensive and efficient psychosocial intervention at community level after a disaster should recognise the importance of dead body management as an integral part of it. The guiding principles of psychosocial interventions are: to be multi-sectoral and multi-level; to include immediate, mid-term and long-term interventions; to be socially and culturally sensitive; to recognize the functionality of existing social and healthcare systems; to adopt a public mental health approach; and to be informed by evidence-based planning and implementation proven to be locally effective.

Cadaver↗
PubMed2001

Organic and hydraulic shock loadings on a biological aerated filter.

The performance of a biological aerated filter (BAF) during short-term (60 min) organic and hydraulic shock loads was investigated. The BAF used for the present experiment was not capable of absorbing high peak organic shock loads when the organic loads were increased from a normal load of 1.2-1.4 kg soluble chemical oxygen demand (sCOD ) m(-3) d(-1) to shock loads between 5.1- 7.3 kg sCOD m(-3) d(-1), based on empty bed volumes. Nevertheless, the effect on the biomass was limited as normal performance resumed very quickly. Increases in the hydraulic velocity from 0.7-1.0 m h(-1) to 1.5-2.9 m h(-1) had little effect on BAF performance in terms of soluble COD removal. Yet, sCOD effluent concentrations of <55 mg l(-1) (approximately 22 mg l(-1) biochemical oxygen demand) were always achieved. The recovery of the reactor in both cases was fast, resuming normal performance within 60 min after the application of the shock load.

Biomass↗
PubMed2006

Effluent quality of a conventional activated sludge and a membrane bioreactor system treating hospital wastewater.

Two lab scale wastewater treatment plants treating hospital wastewater in parallel were compared in terms of performance characteristics. One plant consisted of a conventional activated sludge system (CAS) and comprised an anoxic and aerobic compartment followed by a settling tank with recycle loop. The second pilot plant was a plate membrane bioreactor (MBR). The wastewater as obtained from the hospital had a variable COD (Chemical Oxygen Demand) ranging from 250 to 2300 mg l(-1). Both systems were operated at a similar hydraulic residence time of 12 hours. The reference conventional activated sludge system did not meet the regulatory standard for effluent COD of 125 mg l(-1) most of the time. Its COD removal efficiency was 88%. The plate MBR delivered an effluent with a COD value of 50 m g l(-1) or less, and attained an efficiency of 93%. The effluent contained no suspended particles. In addition, the MBR resulted in consistent operational parameters with a flux remaining around 8-10 l m(-2) h(-1) and a trans membrane pressure < 0.1 bar without the need for backwash or chemical cleaning. The CAS and the MBR system performed equally well in terms of TAN removal and EE2 removal. The CAS system typically decreased bacterial groups for about 1 log unit, whereas the MBR decreased these groups for about 3 log units. Enterococci were decreased below the detection limit in the MBR and indicator organisms such as fecal coliforms were decreased for 1.4 log units in the CAS system compared to a 3.6 log removal in the MBR.

Bioreactors↗
PubMed2001

Development and performance of an alternative biofilter system.

Step tracer tests were carried out on lab-scale biofilters to determine the residence time distributions (RTDs) of gases passing through two types of biofilters: a standard biofilter with vertical gas flow and a modified biofilter with horizontal gas flow. Results were used to define the flow patterns in the reactors. "Non-ideal flow" indicates that the flow reactors did not behave like either type of ideal reactor: the perfectly stirred reactor [often called a "continuously stirred tank reactor" (CSTR)] or the plug-flow reactor. The horizontal biofilter with back-mixing was able to accommodate a shorter residence time without the usual requirement of greater biofilter surface area for increased biofiltration efficiency. Experimental results indicated that the first bed of the modified biofilter behaved like two CSTRs in series, while the second bed may be represented by two or three CSTRs in series. Because of the flow baffles used in the horizontal biofilter system, its performance was more similar to completely mixed systems, and hence, it could not be modeled as a plug-flow reactor. For the standard biofilter, the number of CSTRs was found to be between 2 and 9 depending on the airflow rate. In terms of NH3 removal efficiency and elimination capacity, the standard biofilter was not as good as the modified system; moreover, the second bed of the modified biofilter exhibited greater removal efficiency than the first bed. The elimination rate increased as biofilter load increased. An opposite trend was exhibited with respect to removal efficiency.

Air Pollutants, Occupational↗
PubMed2001

Oxidation of gas mixtures containing dimethyl sulfide, hydrogen sulfide, and methanethiol using a two-stage biotrickling filter.

A biofiltration technique was developed for removing a mixture of hydrogen sulfide (H2S), methanethiol (MeSH), and dimethyl sulfide (Me2S) from waste gases. Since H2S, especially at high concentrations, disturbs the removal of Me2S, two biotrickling filters with different microbes and operating pH levels were connected in series to create a two-stage system. Different loads of these gases were studied in order to determine their impact on the removal capacity of the system. The microbial consortia for these filters were enriched from the sludge of a Finnish refinery with bubbling H2S or Me2S. Acclimation for Me2S took 2 weeks, though no acclimation time was needed for the other gases. The first filter, at a pH of 2, removed most of the H2S and some of the MeSH and Me2S. The second filter, at a pH of approximately 6.5, removed the rest of the MeSH and most of the Me2S. The total maximum loads of the whole two-stage biotrickling filter were 1150 g/m3/day for H2S-S (suffix S indicates the results are counted as sulfur amounts), 879 g/m3/day for Me2S-S, and 66 g/m3/day for MeSH-S treated in a gas mixture. The average removal efficiencies for all gases tested were 99% or higher.

Air Pollutants, Occupational↗
PubMed2001

Combined PCDD/F destruction and particulate control in a baghouse: experience with a catalytic filter system at a medical waste incineration plant.

Phoenix Services, Inc., owns and operates the Baltimore Regional Medical Waste Incinerator in Baltimore, MD. New regulations for dioxins and furans imposed a limit that was considerably below historical emission levels. To determine a method to comply with the new dioxin/furan regulations, Phoenix Services performed trials with powdered activated carbon (PAC). Although the results with carbon were acceptable, Phoenix Services decided to replace their woven fiberglass filter bags with catalytic filters that simultaneously destroy dioxins and furans and collect particulate matter (PM). The catalytic filter system offered several advantages to Phoenix Services, including destruction of dioxins and furans instead of adsorption on carbon. The catalytic filters also offered a passive solution that did not require new carbon injection equipment. In January 2000, a campaign to measure dioxins/furans and PM was undertaken. The measurements allowed the catalytic filter system to be evaluated. Some of the key findings of this investigation are The dioxin/furan emission was less than 0.1 ng toxicity equivalents (TEQ)/Nm3 at 11% O2. This concentration is approximately 2 orders of magnitude less than historical averages and it is well below the new regulatory limits, for both existing and new sources of this type; the amount of dioxin/furans destroyed by the catalytic filters was approximately 1.73 ng TEQ/Nm3 at 11% O2; and the particulate emission was 12-17 times less than the regulatory limit.

Benzofurans↗
PubMed2002

Establishing the propensity for dioxin formation using a plume temperature model for medical waste incinerator emissions in developing countries.

Air pollution control devices (APCDs) are not compulsory for medical waste incinerators (MWIs) in developing countries. In South Africa, combustion gases are usually vented directly to the atmosphere at temperatures greater than the formation temperature of dioxin. The possibility of dioxin formation outside the incinerator stack has been hypothesized. A plume model has been developed and tested in the wind tunnel with a scale model of an incinerator stack. The plume temperature and trajectory predictions of the plume model were verified within a +/- 3% experimental accuracy. Using South African data, the plume model predicts that the residence time of gases in the temperature range of 150-450 degrees C in a plume is 1.3 sec on average for 5% of a year (18 days) at meteorological conditions resulting in wind speeds of less than 1 m/sec. Two published dioxin formation models were used to assess the probability of dioxin formation in the plume. The formation models predict that the average polychlorinated dibenzodioxins/furans (PCDD/Fs) formed in the plume will exceed the stack emission regulations in South Africa of 0.2 ng/Nm3 toxic equivalent quotient (TEQ) by between 2 and 40 times. The calculated concentrations do not include additional gaseous PCDD/F compounds that may be formed at high-temperature post-combustion zones through pyrosynthesis mechanisms.

Air Pollution↗
PubMed2003

Impact of polycyclic aromatic hydrocarbon emissions from medical waste incinerators on the urban atmosphere.

In this study, polycyclic aromatic hydrocarbon (PAH) emissions from two batch-type medical waste incinerators (MWIs), one with a mechanical grate and the other with a fixed grate, both operated by a medical center, were assessed. Both MWIs shared the same air-pollution control devices (APCDs), with an electrostatic precipitator and a wet scrubber installed in series. Results show that when APCDs were used, total PAHs and total benzo[a]pyrene equivalent (total BaP(eq)) emission concentrations of both MWIs were reduced from 2220 to 1870 microg/m3 and 50 to 12.4 microg/m3, respectively. We used the Industrial Source Complex Short Term model (ISCST) to estimate the ground-level concentrations of the residential area and the traffic intersection located at the downwind side of the two MWIs. For the traffic intersection, we found both total PAHs and total BaP(eq) transported from MWIs to both studied areas were not significant. For the residential area, similar results were found when APCDs were used in MWIs. When APCDs were not included, we found that total PAHs transported from MWIs accounted for < 12%, but total BaP(eq) accounted for > 90%, of the on-site measured concentrations. These results suggest that the use of proper APCDs during incineration would significantly reduce the carcinogenic potencies associated with PAH emissions from MWIs to the residential area.

Air Pollutants↗
PubMedDate not supplied

Analogical reasoning in handling emerging technologies: the case of umbilical cord blood biobanking.

How are we individually and as a society to handle new and emerging technologies? This challenging question underlies much of the bioethical debates of modern times. To address this question we need suitable conceptions of the new technology and ways of identifying its proper management and regulation. To establish conceptions and to find ways to handle emerging technologies we tend to use analogies extensively. The aim of this article is to investigate the role that analogies play or may play in the processes of understanding and managing new technology. More precisely we aim to unveil the role of analogies as analytical devices in exploring the "being" of the new technology as well the normative function of analogies in conceptualizing the characteristics and applications of new technology. Umbilical cord blood biobanking will be used as a case to investigate these roles and functions.

Bioethical Issues↗
PubMed2005

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in serum samples of workers at an infectious waste incineration plant in Japan.

In 1998-2000, concentrations of summed polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the exhaust gas of an infectious waste incineration plant were 17-510 ng toxic equivalents (TEQ)/m(3), which reached levels above the Japanese legal limit value of 80 ng TEQ/m(3). The incinerator ceased operation in November 2000. This study was aimed at determining whether the incinerator workers were exposed to high levels of PCDDs and PCDFs. Blood samples of five workers were collected at 1 month and 16 months after the end of the occupational dioxin exposure. For comparison, blood samples were also collected from control subjects. Ash remaining in the incinerator and dust deposited around the conveyer and incinerator areas were collected; TEQ values were 44 and 10 ng TEQ/g, respectively. A month after the end of occupational dioxin exposure, mean TEQ for the workers was 49.1 pg TEQ/g lipid, which was 2.7 times as high as that for the controls. At 16 months, the mean TEQ for the workers decreased to 29.4 pg TEQ/g lipid, which was 1.6 times that for the controls. Ratios of serum level of each congener of PCDDs and PCDFs between 1 and 16 months after exposure were 0.44 to 0.69. This study showed that the serum dioxin levels for the infectious waste incinerator workers were higher than the controls, and the serum dioxin level decreased after the end of the occupational dioxin exposure.

Adult↗
PubMed2003

Disinfection of hospital wastewater by continuous ozonization.

The disinfection of hospital wastewaters using the ozonization process was studied. The concentrations of ozone required to reach a sudden drop of coliform and Pseudomonas aeruginosa in the wastewater are 4.0-7.0 and 3.0-5.0 mg L(-1), respectively. For the hospital wastewater, the disinfection efficiencies were 0.518S(-1.1) for coliforms, 0.509S(-1.06) for Pseudomonas aeruginosa and 0.254S-(1.54) for total count, respectively. As to the effects of ozone input methods on the disinfection efficiency, the continuous ozonization process was ten times higher than the batch input process. The low COD removal rate was obtained at 25.0 mgL(-1) of ozone concentration for hospital wastewater. However, more biodegradable compounds resulted in the treated mixture.

Biodegradation, Environmental↗
PubMed2006

Hospital waste generation during an outbreak of severe acute respiratory syndrome in Taiwan.

During the SARS outbreak in Taiwan, the number of ambulatory patients and inpatients treated at one medical center decreased by 40%-70% because of the increasing number of SARS patients. At the peak of the epidemic, the amount of hospital infectious waste had increased from a norm of 0.85 kg per patient-day to 2.7 kg per patient-day. However, the hospital was able to return the generation of waste to normal levels within 10 days.

Disease Outbreaks↗
PubMed2003

Preventing accidental transmission of human transmissible spongifom encephalopathies.

The mechanism by which humans became infected with the BSE agent is discussed, and the matter of potential person-to person transmission of TSEs through contagion or medical procedures is considered. There is some discussion regarding the current evidence relating to whether or not the blood of humans infected with TSEs is infectious. Considerable emphasis is placed on the fact that TSE agents are known to be relatively resistant to decontamination by procedures that are effective with conventional micro-organisms, including (under worst-case conditions) the autoclaving procedures used to sterilise surgical instruments. Methods for providing additional re-assurance with regard to the safety of instruments are described. Safety in the pathology laboratory is discussed extensively because TSE agents are not inactivated by the usual processes used to fix tissues, and such laboratories will receive fixed tissues that are still highly infectious as far as TSE agents are concerned.

Animals↗
PubMed2003

What's hot in animal biosafety?

In recent years, the emergence or re-emergence of critical issues in infectious disease and public health has presented new challenges and opportunities for laboratory animal care professionals. The re-emergence of bioterrorism as a threat activity of individuals or small groups has caused a heightened awareness of biosecurity and improved biosafety. The need for animal work involving high-risk or high-consequence pathogens and for arthropod-borne diseases has stimulated renewed interest in animal biosafety matters, particularly for work in containment. Application of these principles to animals retained in outdoor environments has been a consequence of disease eradication programs. The anticipated global eradication of wild poliovirus has prompted the promulgation of new biosafety guidelines for future laboratory and animal work. Increased concern regarding the use of biologically derived toxins and hazardous chemicals has stimulated a new categorization of facility containment based on risk assessment. Recognition that prion disease agents and other high-consequence pathogens require safe handling and thorough destruction during terminal decontamination treatment has led to the development of new biosafety guidelines and technologies. The implementation of these guidelines and technologies will promote state-of-the-art research while minimizing risk to laboratory animals, researchers, and the environment.

Animals↗