Acute respiratory distress after exposure to chlorine dioxide-based disinfectant.

A hospital cleaner developed acute respiratory distress after working with a chlorine dioxide-based disinfectant. The content of chlorine dioxide in the product is below the limit that would require the product to be labelled as hazardous to health, but we show with a simple estimation that the relevant threshold limit values for chlorine dioxide in the working atmosphere may be exceeded under normal use of the product. This may have implications for risk assessment of the use of such chlorine dioxide-based disinfectants and may warrant stricter regulations for labelling these products.

Chlorine dioxide and chlorine derivatives for the prevention or treatment of COVID-19: a systematic review. / Dióxido de cloro y derivados del cloro para prevenir o tratar la COVID-19: revisión sistemática.

OBJECTIVES: To systematically review the effectiveness and safety of chlorine dioxide solution and chlorine derivatives used in the prevention or treatment of COVID-19. METHODS: This review adheres to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) and follows the guidelines provided in the Cochrane Handbook for Systematic Reviews of Interventions. A librarian developed and executed the search strategy; it was further reviewed by two of the authors and complemented by manual search. Randomized clinical trials, quasi-experimental studies, cohort studies, case-control studies, cross-sectional studies, and case reports were included; in vitro or animal studies were excluded. Abstract and full-text screening according to pre-defined eligibility criteria were performed by two reviewers independently using web application Rayyan QCRI. Disagreements on study selection were resolved by a third reviewer. The systematic review protocol was registered in PROSPERO (CRD42020200641). RESULTS: Neither published nor pre-print studies evaluating the use of chlorine dioxide or derivatives on SARS-CoV-2 infection were identified. The only finding was an unpublished observational study registry which has no results released yet. CONCLUSIONS: To date, there are no scientific evidence to uphold the use of chlorine dioxide or derivatives as preventive or therapeutic agents against COVID-19.

OBJETIVOS: Realizar una revisión sistemática acerca de la efectividad y seguridad del uso de dióxido de cloro y derivados del cloro, en la prevención o el tratamiento de la COVID-19. MATERIALES Y MÉTODOS: Se siguieron las pautas internacionales de elaboración de revisiones sistemáticas de PRISMA y el Manual Cochrane para revisiones sistemáticas de intervenciones. La estrategia de búsqueda la desarrolló un bibliotecario y la revisaron dos de los autores. Se complementó la búsqueda electrónica con una búsqueda manual. Se incluyeron ensayos clínicos aleatorizados, estudios cuasiexperimentales, estudios de cohorte, estudios de casos y controles, estudios de corte transversal y reportes de casos; y se excluyeron estudios in vitro o realizados en animales. Dos revisores, de forma independiente, seleccionaron los estudios según los criterios de elegibilidad definidos, usando el aplicativo web Rayyan, en caso de discordancia se hizo partícipe a un tercer revisor. El protocolo de la revisión sistemática se registró en PROSPERO (CRD42020200641). RESULTADOS: No se identificó ningún estudio publicado ni en proceso de publicación que haya evaluado el uso del dióxido de cloro o derivados del cloro, administrado por vía inhalatoria, oral o parenteral en humanos, como agente preventivo o terapéutico de la COVID-19 o en infecciones por otros coronavirus. Solo se identificó el registro de un único estudio catalogado como observacional que hasta ahora no tiene resultados. CONCLUSIONES: A la fecha, no existe evidencia científica que apoye el uso del dióxido de cloro o derivados del cloro para prevenir o tratar la COVID-19.

Tracking of the degradation process of chlorhexidine digluconate and ethylenediaminetetraacetic acid in the presence of hyper-pure chlorine dioxide in endodontic disinfection.

Accurate knowledge of the safety of the combined use of hyper-pure chlorine dioxide (ClO2, Solumium) with different endodontic agents is not known. The objective was to investigate the possible interactions between hyper-pure ClO2 and Chlorhexidine digluconate (CHX) as well as hyper-pure ClO2 and ethylenediaminetetraacetic acid (EDTA) in vitro. High-performance liquid chromatography (HPLC) was used to analyse the reaction between ClO2 and CHX for studying the possible increase of para-chloroaniline (PCA). Nuclear magnetic resonance (NMR) method was applied to investigate if the oxidising property of ClO2 inactivates EDTA. CHX itself may contain PCA; however, its amount did not increase after the mixing up with ClO2. While ClO2 did not oxidise PCA, on the other hand, it oxidised EDTA into numerous degradation products, but this reaction was slow. Hyper-pure ClO2 of excellent antimicrobial properties should be considered as a safe alternative endodontic disinfectant agent in combinations or as a final rinse. The lack of chemical interaction between ClO2 and CHX confirms their safe application in combination.

Impact of chlorine dioxide disinfection of irrigation water on the epiphytic bacterial community of baby spinach and underlying soil.

The contamination of pathogenic bacteria through irrigation water is a recognized risk factor for fresh produce. Irrigation water disinfection is an intervention strategy that could be applied to reduce the probability of microbiological contamination of crops. Disinfection treatments should be applied ensuring minimum effective doses, which are efficient in inhibiting the microbial contamination while avoiding formation and accumulation of chemical residues. Among disinfection technologies available for growers, chlorine dioxide (ClO2) represents, after sodium hypochlorite, an alternative disinfection treatment, which is commercially applied by growers in the USA and Spain. However, in most of the cases, the suitability of this treatment has been tested against pathogenic bacteria and low attention have been given to the impact of chemical residues on the bacterial community of the vegetable tissue. The aim of this study was to (i) to evaluate the continual application of chlorine dioxide (ClO2) as a water disinfection treatment of irrigation water during baby spinach growth in commercial production open fields, and (ii) to determine the subsequent impact of these treatments on the bacterial communities in water, soil, and baby spinach. To gain insight into the changes in the bacterial community elicited by ClO2, samples of treated and untreated irrigation water as well as the irrigated soil and baby spinach were analyzed using Miseq® Illumina sequencing platform. Next generation sequencing and multivariate statistical analysis revealed that ClO2 treatment of irrigation water did not affect the diversity of the bacterial community of water, soil and crop, but significant differences were observed in the relative abundance of specific bacterial genera. This demonstrates the different susceptibility of the bacteria genera to the ClO2 treatment. Based on the obtained results it can be concluded that the phyllosphere bacterial community of baby spinach was more influenced by the soil bacteria community rather than that of irrigation water. In the case of baby spinach, the use of low residual ClO2 concentrations (approx. 0.25 mg/L) to treat irrigation water decreased the relative abundance of Pseudomonaceae (2.28-fold) and Enterobacteriaceae (2.5-fold) when comparing treated versus untreated baby spinach. Members of these two bacterial families are responsible for food spoilage and foodborne illnesses. Therefore, a reduction of these bacterial families might be beneficial for the crop and for food safety. In general it can be concluded that the constant application of ClO2 as a disinfection treatment for irrigation water only caused changes in two bacterial families of the baby spinach and soil microbiota, without affecting the major phyla and classes. The significance of these changes in the bacterial community should be further evaluated.

Proposal of a flow scheme for the chemical-form-based quantitative analysis of chlorine compounds in pulp for sanitary products and verification of safety.

To determine the amounts and chemical forms of chlorine compounds in elemental chlorine-free (ECF) bleached pulp for sanitary products, a chemical-form-based quantitative analysis flow scheme was created. The scheme involves quantitative determination of compounds eluted in elution tests assuming dermal exposure. The results indicated that most of the chlorine compounds in pulp used for sanitary products were insoluble organically bound chlorine and water-soluble chlorides consisting of chloride ions. The total amount of chlorine obtained by analysis of the total chlorine in the pulp products was close to the sum of the amounts of water-soluble chlorides, residual chlorine, chloroacetic acids, and insoluble organically bound chlorine. Therefore, the balance of chlorine measured by the flow scheme was acceptable. Little residual chlorine was detected in the pulp products, suggesting that the chlorine dioxide used for bleaching was almost completely converted into inactive inorganic chlorides and organic chlorine compounds and that these substances do not affect the health risk posed by pulp products. A risk assessment of the detected chloroacetic acid and dichloroacetic acid revealed that there is no concern about the health risk posed by use of these products.

Disinfection by-products effect on swimmers oxidative stress and respiratory damage.

Disinfection by-products (DBPs) are generated through the reaction of chlorine with organic and inorganic matter in indoor swimming pools. Different DBPs are present in indoor swimming pools. This study evaluated the effects of different chlorinated formations in oxidative stress and lung damage in 20 swimmers after 40 min of aerobic swimming in 3 indoor pools with different characteristics. Biological samples were collected to measure lung damage (serum-surfactant-associated proteins A and B), oxidative stress parameters (plasma protein carbonylation and malondialdehyde, and whole-blood glutathione oxidation), and swimming exertion values (blood lactate) before and after exercise. Free chlorine and combined chlorine in water, and chlorine in air samples were determined in all the swimming pools. Chlorination as disinfection treatment led to the formation of chloramines in water samples, mainly mono- and dichloramine. However, free chlorine was the predominate species in ultraviolet-treated swimming pool. Levels of total chlorine increased as a function of the swimming activity in chlorinated swimming pools. The lower quality of the installation resulted in a higher content of total chlorine, especially in air samples, and therefore a higher exposure of the swimmer to DBPs. However, the concentration level of chlorinated DBPs did not result in significant variation in serum-surfactant-associated proteins A and oxidative stress parameters in swimmers. In conclusion, the quality of the installation affected the DBPs concentration; however, it did not lead to lung epithelial damage and oxidative stress parameters in swimmers.

Safety issues of tooth whitening using peroxide-based materials.

In-office tooth whitening using hydrogen peroxide (H2O2) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H2O2, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

Use of chlorine dioxide gas for the postharvest control of Alternaria alternata and Stemphylium vesicarium on Roma tomatoes.

BACKGROUND: Tomatoes and potatoes are the top produce affected in terms of value lost in the USA. Postharvest losses can occur anywhere from the time of harvest to the consumers' decision to eat or discard the food. These data support the importance of finding sustainable strategies to minimise food waste and preserve resources. This study evaluated the potential application of chlorine dioxide gas (ClO2 ) technology to control the postharvest spoilage of Roma tomatoes by Alternaria alternata and Stemphylium vesicarium. RESULTS: Data analysis showed that exposure time was a significant factor for fungal disease control (P < 0.05). After 3 min of treatment, mycelial growth was completely inhibited for A. alternata and S. vesicarium. Similar results were observed for conidial germination. The efficacy of ClO2 treatments was also studied under in vivo conditions. While untreated Roma tomatoes developed white moulds and black spots after 5 days of storage, produce decay was significantly (P < 0.05) delayed after 5 and 7 min treatments for S. vesicarium and A. alternata respectively. CONCLUSION: The use of ClO2 in the food industry is regulated by both the FDA and the EPA. Currently, only acidified sodium chlorite solutions are approved for the control of micro-organisms in water used to wash fruits and vegetables. No direct applications of ClO2 gas on fresh fruits and vegetables can be found in the regulations. More data are required by the two agencies to demonstrate that residues of ClO2 on produce surfaces are acceptable for human consumption.

Occupational exposure to chlorinated solvents and risks of glioma and meningioma in adults.

OBJECTIVES: Chlorinated solvents are classified as probable or possible carcinogens. It is unknown whether exposure to these agents increases the risk of malignant or benign brain tumours. Our objective was to evaluate associations of brain tumour risk with occupational exposure to six chlorinated solvents (i.e., dichloromethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene and perchloroethylene). METHODS: 489 glioma cases, 197 meningioma cases and 799 controls were enrolled in a hospital-based case-control study conducted at three U.S.A. hospitals in Arizona, Massachusetts and Pennsylvania. Information about occupational history was obtained through a detailed inperson interview that included job-specific modules of questions such that the interview was tailored to each individual's particular work history. An industrial hygienist assessed potential solvent exposure based on this information and an exhaustive review of the relevant industrial hygiene literature. Unconditional logistic regression models were used to calculate OR and 95% CI for each solvent for ever/never, duration, cumulative, average weekly and highest exposure. RESULTS: Overall, we found no consistent evidence of an increased risk of glioma or meningioma related to occupational exposure to the six chlorinated solvents evaluated. There was some suggestion of an association between carbon tetrachloride and glioma in analyses restricted to exposed subjects, with average weekly exposure above the median associated with increased risk compared with below the median exposure (OR = 7.1, 95% CI 1.1 to 45.2). CONCLUSIONS: We found no consistent evidence for increased brain tumour risk related to chlorinated solvents.

Severe and rapid erosion of dental enamel from swimming: a clinical report.

The diagnosis and treatment of a patient with excessive and rapid erosion of enamel is presented. Although the Center for Disease Control and the dental literature have reported on dental enamel erosion resulting from swimming pool chlorination, the awareness of such etiology among dental professionals may be limited. Common findings in these reports include cold sensitivity, a distinctive appearance resembling laminate veneer preparations of the facial surfaces of anterior teeth, occurrence of diastemas, and at times, a rough or gritty texture of the remaining tooth structure. Clinical presentations of erosive lesions can be diagnosed and the best course of treatment determined.

[Physiological and psychophysiological indices dynamics in operators with three-shift working day in different working conditions].

It was shown that intense operator work in pulp and paper industry (bleachers and chlorinators) with changes in shift time (day, evening, night) causes fatigue. The fatigue in operators was indicated by increasing number of errors in sensomotor coordination test and coordination index, and among chlorinators it was accompanied by deterioration of state of health. Manifestations of 24 hours' rhythm of physiological functions were detected by changes in body temperature (among bleachers), heart rate, blood pressure and sensomotor coordination indices (all operators). Harmful chemical substances (chlorine and chlorine dioxide) in the air negatively influence psychophysiological status among clorinators.

Evaluation of chlorine dioxide gas residues on selected food produce.

In recent years, the consumption of fresh fruits and vegetables has greatly increased, and so has its association with contamination of several foodborne pathogens (Listeria, Salmonella, and Escherichia coli). Hence, there is a need to investigate effective sanitizer systems for produce decontamination. Chlorine dioxide (ClO(2)), a strong oxidizing gas with broad spectrum and sanitizing properties, has previously been studied for use on selected fruits and vegetables. ClO(2) gas treatments show great potential for surface pathogen reduction; however its use from a residue safety standpoint has yet to be assessed. Thus, the objective of this study was to evaluate residues of ClO(2), chlorite, chlorate, and chloride on selected fresh produce surfaces after treatment with ClO(2) gas. A rinse procedure was used and water samples were analyzed by N, N-diethyl-p-phenylenediamine and ion chromatography method (300.0). Seven different foods--tomatoes, oranges, apples, strawberries, lettuce, alfalfa sprouts, and cantaloupe--were analyzed after ClO(2) treatment for surface residues. Very low residues were detectable for all the food products except lettuce and alfalfa sprouts, where the measured concentrations were significantly higher. Chlorine dioxide technology leaves minimal to no detectable chemical residues in several food products, thus result in no significant risks to consumers. Practical Application: Potential for chlorine dioxide gas treatments as an effective pathogen inactivation technology to produce with minimal risk for consumers.

Pulmonary function in pubertal synchronized swimmers: 1-year follow-up results and its relation to competitive achievement.

Pulmonary function (PF) is particularly important in synchronized swimming, considering the characteristics of this sport. However, the sanitizing agents (chlorine) used in pools can have a possible negative influence on the PF parameters. In this study, we observed 24 swimmers (all women, 14 to 16 years of age) and measured their PF and competitive achievement. PF was measured before and after a 1-year period and included standard spirometric variables. Competitive achievement was evidenced during the National Championship. The t-test showed significant increases in body height and weight of the participants and a resulting increase in most of the absolute respiratory flows and pulmonary capacities. Forced vital capacity (FVC) and forced expiratory volume (both in proportion to norm for body height, gender, and age) increased significantly within the study period. FVC significantly predicted the competitive achievement of young swimmers, most probably because artists have to achieve exceptional breath control when upside down underwater. In conclusion, we found no evidence for the eventual negative influence of chlorine and its compounds on the PF of swimmers, and results showed that regular synchronized swim training could improve the PF of young artists.

Water for haemodialysis and related therapies: recent standards and emerging issues.

Dialysis is a well-established and widely used procedure. For a number of years, the focus has been on ensuring that water used in the preparation of dialysis fluid meets the required chemical and microbiological quality and complies with national or international standards which have recently been updated. Continued vigilance is required, in particular when new chemicals such as silver-stabilized hydrogen peroxide and chlorine dioxide are used to prevent growth of Legionella bacteria in hospital water systems, since residues are harmful to patients receiving dialysis. To achieve the required quality, large volumes of water are processed, and a substantial portion is sent to waste via the municipal sewer systems with little attempt to reuse such water on site. In view of concern about global warming and climate change, there is a need to adopt a more environmentally conscious attitude requiring dialysis providers to focus on this aspect of water usage.

Health risks of early swimming pool attendance.

Swimming pool attendance and exposure to chlorination by-products showed adverse health effects on children. We assessed whether early swimming pool attendance, especially baby swimming, is related to higher rates of early infections and to the development of allergic diseases. In 2003-2005, 2192 children were analysed for the 6-year follow-up of a prospective birth cohort study. Data on early swimming pool attendance, other lifestyle factors and medical history were collected by parental-administered questionnaire. Bivariate and multivariate logistic regression analyses were used to evaluate associations. Babies who did not participate in baby swimming had lower rates of infection in the 1st year of life (i) diarrhoea: OR 0.68 CI 95% 0.54-0.85; (ii) otitis media: OR 0.81 CI 95% 0.62-1.05; (iii) airway infections: OR 0.85 CI 95% 0.67-1.09. No clear association could be found between late or non-swimmers and atopic dermatitis or hay fever until the age of 6 years, while higher rates of asthma were found (OR 2.15 95% CI 1.16-3.99), however, potentially due to reverse causation. The study indicates that, in terms of infections, baby swimming might not be as harmless as commonly thought. Further evidence is needed to make conclusions if the current regulations on chlorine in Germany might not protect swimming pool attendees from an increased risk of gastrointestinal infections. In terms of developing atopic diseases there is no verifiable detrimental effect of early swimming.

Efficacy of potato seeds disinfection products to control Erwinia spp.

Erwinia spp. provokes soft rot on potato tubers during storage. No disinfection products are available on the market in the European Union to control these bacteria. We tested 3 products presented as good candidates to cure potato tubers from bacterial diseases. First, Anthium 500 (Du Pont de Nemours) a product based on chlorine dioxyde, then Phostrol (Nufarm) with phosphoric acid as a.i. and finally Solucuivre (Proval), a copper based product. We firstly managed disinfection trials: high Erwinia contaminated potato seed samples were treated by immersion and were then incubated, we observed the percentage of tubers rotting. Secondly, we managed protection trials: protected healthy tubers were incubated during 23 days in contact with rotting tubers. We evaluated weight loss after symptoms development. No tested product was effective to control Erwinia spp. on seed tubers in our trials conditions. Furthermore, we observed more rot development after Phostrol and Solucuivre application. We suppose that the product couldn't reach the latent bacteria and weakened the tubers. No protection effect was observed.

Screening and estimating of toxicity formation with photobacterium bioassay during chlorine disinfection of wastewater.

Reclamation and reuse of wastewater is one of the most effective ways to alleviate water shortage. Disinfection plays a key role in killing the harmful pathogens in reclaimed water, while an unwanted side effect is the formation of disinfection by-products (DBPs). Recently, a number of researches have been conducted on the formation regularities of certain DBPs. However, with current physiochemical techniques, it is impossible to detect all the DBPs. In this study, photobacterium bioassay was used to measure the formation of DBPs and their toxic effect as a whole. The effects of water quality characteristics and operational conditions on the toxicity formation during wastewater chlorination disinfection process were evaluated. A statistical model, depending on chlorine disinfectant dosage, concentration of ammonia nitrogen, and concentration of dissolved organic carbon, was developed to quantitatively estimate the toxicity formation during the disinfection process. It was found that the toxicity of the wastewater samples was positively correlated with chlorine disinfectant dosage, concentration of dissolved organic carbon and UV absorbance at 254nm, while negatively correlated with concentration of ammonia nitrogen.