Epithelial barrier theory in the context of nutrition and environmental exposure in athletes.

Exposure to toxic substances, introduced into our daily lives during industrialization and modernization, can disrupt the epithelial barriers in the skin, respiratory, and gastrointestinal systems, leading to microbial dysbiosis and inflammation. Athletes and physically active individuals are at increased risk of exposure to agents that damage the epithelial barriers and microbiome, and their extreme physical exercise exerts stress on many organs, resulting in tissue damage and inflammation. Epithelial barrier-damaging substances include surfactants and enzymes in cleaning products, laundry and dishwasher detergents, chlorine in swimming pools, microplastics, air pollutants such as ozone, particulate matter, and diesel exhaust. Athletes' high-calorie diet often relies on processed foods that may contain food emulsifiers and other additives that may cause epithelial barrier dysfunction and microbial dysbiosis. The type of the material used in the sport equipment and clothing and their extensive exposure may increase the inflammatory effects. Excessive travel-related stress, sleep disturbances and different food and microbe exposure may represent additional factors. Here, we review the detrimental impact of toxic agents on epithelial barriers and microbiome; bring a new perspective on the factors affecting the health and performance of athletes and physically active individuals.

Ionic Liquids as Reconditioning Agents for Paper Artifacts.

This research explores the potential of ionic liquids (ILs) in restoring paper artifacts, particularly an aged book sample. Three distinct ILs-1-ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methyl-3-pentylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-methyl-3-heptylimidazolium bis(trifluoromethylsulfonyl)imide -both in their pure form and isopropanol mixtures, were examined for their specific consumption in conjunction with paper, with 1-ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide displaying the highest absorption. Notably, the methyl-3-heptylimidazolium ionic liquid displayed pronounced deacidification capabilities, elevating the paper pH close to a neutral 7. The treated paper exhibited significant color enhancements, particularly with 1-heptyl-3-methylimidazolium and 1-pentyl-3-methylimidazolium ILs, as evidenced by CIE-Lab* parameters. An exploration of ILs as potential UV stabilizers for paper unveiled promising outcomes, with 1-heptyl-3-methylimidazolium IL demonstrating minimal yellowing post-UV irradiation. FTIR spectra elucidated structural alterations, underscoring the efficacy of ILs in removing small-molecular additives and macromolecules. The study also addressed the preservation of inked artifacts during cleaning, showcasing ILs' ability to solubilize iron gall ink, particularly the one with the 1-ethyl-3-propylimidazolium cation. While exercising caution for prolonged use on inked supports is still recommended, ILs are shown here to be valuable for cleaning ink-stained surfaces, establishing their effectiveness in paper restoration and cultural heritage preservation.

Controlling cleaning agent residues in pharmaceutical manufacturing: A harmonized scientific strategy.

This paper proposes a scientifically justified and harmonized strategy to control cleaning agent ingredients' (CAIs) residues in pharmaceutical manufacturing. Firstly, we demonstrate that worst-case cleaning validation calculations on CAI residues with representative GMP standard cleaning limits (SCLs) are enough to control CAI residues of low concern to safe levels. Secondly, a new harmonized strategy for the toxicological assessment of CAI residues is presented and validated. The results establish a framework applicable to cleaning agent mixtures based on hazard and exposure considerations. This framework is primarily based on the hierarchy of a single CAI's critical effect, where the lowest resulting limit may become the driver of the cleaning validation process. The six critical effect groups are: (1) CAIs of low concern based on safe exposure reasoning; (2) CAIs of low concern based on the mode of action reasoning; (3) CAIs with local concentration-dependent critical effects; (4) CAIs with dose-dependent systemic critical effects for which a route-specific PDE should be calculated; (5) poorly characterized CAIs with unknown critical effect for which a default value of 100 µg/day is proposed; (6) poorly characterized CAIs which should be avoided because of potential mutagenicity and/or potency.

Prevalence of work-related skin symptoms and associated factors among tertiary hospital workers exposed to cleaning agents in Southern Africa.

INTRODUCTION: Working with cleaning products is associated with occupational contact dermatitis in health workers (HWs), but information on predictors for these outcomes is limited. OBJECTIVES: This study investigated the prevalence of work-related skin symptoms (WRSS) and associated factors in HWs exposed to cleaning agents in two Southern African tertiary hospitals. METHODS: A cross-sectional study of 697 HWs used an interviewer-administered questionnaire and assessed for atopy using Phadiatop. RESULTS: HWs' median age was 42 years, 77.0% were female and 42.5% were atopic. The prevalence of WRSS in the last 12 months was 14.8%, 12.3% had probable contact dermatitis (PCD) and 3.2% had probable contact urticaria (PCU). Technicians (ORadj 3.91) and tasks involving cleaning and disinfection of skin wounds (ORadj 1.98) were associated with WRSS in the past year. Factors associated with PCD included sterilizing instruments, disinfecting skin before procedures and use of wound adhesives. Factors associated with PCU included specimen preparation using formalin, medical instrument sterilization tasks, and skin/wound cleaning and disinfection. Appropriate glove use when performing patients' skin/wound care was protective against WRSS. CONCLUSIONS: Tasks involving cleaning and disinfecting patients' skin and wounds were associated with WRSS in HWs, especially when performed without gloves.

Job and exposure intensity among hospital cleaning staff adversely affects respiratory health.

BACKGROUND: Occupational exposure to various types of cleaning agents may increase the risk of adverse respiratory health among cleaners. This study investigated the relationship between exposure to cleaning and disinfecting agents, using a job-task and exposure intensity metric, and respiratory outcomes among cleaners. METHODS: A sample of 174 cleaners was selected from three public hospitals in Durban. A questionnaire was used to collect demographic and occupational information, and spirometry, including post-bronchodilator measures, was conducted according to the American Thoracic Society guidelines and skin prick testing were performed. Exposure metrics for job tasks and chemical exposures were created using frequency and employment-lifetime duration of exposure. Multivariate analysis regression models used job task and exposure intensity metrics. RESULTS: Doctor-diagnosed asthma prevalence was 9.8%. Breathlessness with wheeze (22.4%) was the prevalent respiratory symptom. Positive responses to skin prick testing were seen in 74 (43.2%). There was a statistically significant increased risk for shortness of breath with exposure to quaternary ammonium compounds (odds ratio [OR]: 3.44; 95% confidence interval [CI]: 1.13-10.5) and breathlessness with exposure to multipurpose cleaner (OR: 0.34; CI: 0.12-0.92). The losses in percent-predicted forced expiratory volume in 1 s (FEV1) ranged from 0.3%-6.7%. Results among the bronchodilator-positive (8.6%) showed lung function losses twofold greater when compared to the total study population with percentage predicted FEV1 (-22.6 %; p < 0.000). CONCLUSION: Exposure to certain cleaning and disinfectant agents adversely affects respiratory health, particularly lung function. This effect, while seen generally among cleaning workers, is more pronounced among those with pre-existing reversible obstructive lung disease.

Surface Characteristics and Microbial Adhesion in Polymethylmethacrylate for Denture Base Submitted to Antimicrobial Agents and Cleaning Agents: A Systematic Review.

This review aimed to identify the influence of antimicrobial and cleaning agents on surface characteristics such as surface free energy (SFE) and wettability, and microbial adhesion in polymethylmethacrylate (PMMA) for denture base. The review question, based on PICO, was: "Does intervention with antimicrobial and cleaning agents in PMMA influence the surface free energy, wettability, and consequently the microbial adhesion?" and the protocol was registered in Open Science Framework (osf. io/v3xgn). The search was performed in PubMed, Lilacs, Embase, Scopus, and Science Direct databases, using the terms: ("acrylic resin" OR PMMA) AND (antimicrobial OR antibacterial) AND ("electrostatic interaction" OR surface free energy) AND (biofilm OR "bacteria adhesion"), and resulted in 462 articles, of which 7 were included. The antimicrobials polypara-xylylene, carboxybetaine methacrylate, ethylene glycol methacrylate phosphate, and deposition of F and Ag ions in PMMA influenced the SFE and wettability. Denture cleaners reduced microbial adhesion. Five of the included studies evaluated the microbial adhesion, however, only two observed a direct relationship between SFE, wettability, and microbial adhesion. It was concluded that the intervention with antimicrobial and cleaning agents in PMMA can interfere in SFE and surface wettability, but no correlation was observed between microbial adhesion and these surface characteristics in PMMA.

Cleaning agent usage in healthcare professionals and relationship to lung and skin symptoms.

BACKGROUND AND OBJECTIVES: Healthcare workers have an increased risk of respiratory symptoms and dermatitis, likely related to cleaning/disinfecting agents. The aim of this study was to identify work tasks and cleaning/disinfecting agents associated with respiratory symptoms and hand dermatitis among healthcare workers in a tertiary hospital. METHODS: Cleaning agent usage, respiratory symptoms and skin symptoms were recorded by participants using a questionnaire in a cross-sectional study. Age and sex adjusted odds ratios (OR) were used to examine associations between job tasks, exposures, respiratory, and skin outcomes. RESULTS: Two hundred and thirty healthcare workers who were exposed to cleaning agents were compared with 77 who had no, or minimal, exposure. Exposed workers had an increased risk of respiratory symptoms (adjusted OR = 2.17; 95% CI: 1.18-4.14) and skin symptoms (adjusted OR = 1.77; 95% CI: 1.00 - 3.17). Washing instruments manually, using aerosol products, cleaning operating rooms, cleaning sanitary rooms, preparing disinfectants, and filling devices with cleaning products were cleaning tasks associated with various respiratory symptoms. Bleach was the only cleaning agent associated with a respiratory symptom: tightness in the chest (unadjusted OR = 2.46; 95% CI: 1.01-6.89) but statistical significance did not persist after adjustment for age and sex. Hand dermatitis was associated with actual disinfecting tasks (adjusted OR = 2.19; 95% CI: 1.10-4.66). Bleach was the only cleaning agent significantly associated with hand dermatitis (adjusted OR = 2.54; 95% CI: 1.32-5.13). CONCLUSIONS: This study provides insight into possible work tasks that need interventions to reduce or prevent respiratory and skin symptoms in healthcare workers.

PDE concept for controlling cleaning agent residues in pharmaceuticals- A critical analysis.

Cleaning agents (CAs) are used in multipurpose facilities to control carryover contamination of active pharmaceutical ingredients (APIs) to scientifically justified limits. While this is often done with the PDE methodology used for API impurities, it is unclear if it is justifiable and necessary for cleaning agents, which generally represent a comparatively lower health risk. Comparing calculated oral PDE values for CA ingredients (CAIs) from four companies with PDEs of a selected number of small-molecule APIs showed that the toxicity of CAIs is several orders of magnitude lower. Furthermore, a critical review of the toxicity and everyday exposure to the general population of the main CAIs functional groups showed that the expected health risks are generally negligible. This is particularly true if the associated mode of actions cause local toxicity that is usually irrelevant at the concentration of potential residue carryover. This work points towards alternative approaches to the PDE concept to control CAIs' contamination and provides some guidance on grouping and identifying compounds with lower health risks based on exposure and mode of action reasoning. In addition, this work supports the concept that limit values should only be set for CAIs of toxicological concern.

Work-related allergy and asthma associated with cleaning agents in health workers in Southern African tertiary hospitals.

BACKGROUND: Health workers (HWs) are exposed to diverse cleaning agents in large hospitals. This study determined the prevalence of work-related symptoms, allergic sensitization, and lung function abnormalities in HWs of two tertiary hospitals in Southern Africa. METHODS: A cross-sectional study of 699 HWs (South Africa: SAH, n = 346; Tanzania: TAH, n = 353) was conducted. Health outcomes were assessed using a standardized ECRHS questionnaire, immunological tests (specific IgE antibody to common aero-allergens and to occupational allergens: natural rubber latex [NRL]  Hev b5 and Hev b6.02, chlorhexidine, and ortho-phthalaldehyde [OPA]), spirometry [pre-and post- bronchodilator], methacholine challenge, and fractional exhaled nitric oxide (FeNO). RESULTS: A large proportion of participants (78%) were women. Median age was 42 years, with 76% nurses, 12% cleaners, and 5% administrative workers. Current smoking was more common in SAHWs (12%) than TAHWs (1%). The overall prevalence of doctor-diagnosed asthma was 7%. Atopy was present in 43% of HWs, while 4% were sensitized to OPA, 2% to NRL, and 1% to chlorhexidine. Prevalence of work-related ocular-nasal symptoms (16%) was higher than skin (12%) and chest (7%) symptoms. TAHWs had significantly lower mean lung volumes, higher degrees of significant airflow obstruction and impaired lung function. The prevalence of bronchial hyperresponsiveness in SAHWs (14%) was high. Overall, 23% of HWs had abnormal FeNO; 6% having high (>50 ppb) levels. FeNO was positively associated with sensitization to occupational allergens, primarily OPA and NRL. CONCLUSIONS: HWs from both hospitals had similar prevalence of work-related respiratory symptoms. Sensitization to OPA and NRL appears to be contributing to allergic airway inflammation in these HWs.

Silver Nanoparticle Interactions with Surfactant-Based Household Surface Cleaners.

Silver nanoparticles (AgNPs) are the most widely used engineered nanomaterials in consumer products, primarily due to their antimicrobial properties. This widespread usage has resulted in concerns regarding potential adverse environmental impacts and increased probability of human exposure. As the number of AgNP consumer products grows, the likelihood of interactions with other household materials increases. AgNP products have the potential to interact with household cleaning products in laundry, dishwashers, or during general use of all-purpose surface cleaners. This study has investigated the interaction between surfactant-based surface cleaning products and AgNPs of different sizes and with different capping agents. One AgNP consumer product, two laboratory-synthesized AgNPs, and ionic silver were selected for interaction with one cationic, one anionic, and one nonionic surfactant product to simulate AgNP transformations during consumer product usage before disposal and subsequent environmental release. Changes in size, morphology, and chemical composition were detected during a 60 min exposure to surfactant-based surface cleaning products using ultraviolet-visible (UV/Vis) spectroscopy, transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX), and dynamic light scattering (DLS). Generally, once AgNP suspensions were exposed to surfactant-based surface cleaning products, all the particles showed an initial aggregation, likely due to disruption of their capping agents. Over the 60 min exposure, cleaning agent-1 (cationic) showed more significant particle aggregates than cleaning agent-2 (anionic) and cleaning agent-3 (nonionic). In addition, UV/Vis, TEM-EDX, and DLS confirmed formation of incidental AgNPs from interaction of ionic silver with all surfactant types.

Unintentional effects of cleaning a crime scene-when the sponge becomes an accomplice in DNA transfer.

DNA transfer in aqueous solutions as well as the persistence of DNA on washed items has become a major subject of research in recent years and is often a significant problem in court. Despite these approaches, the question about the "mobility" of DNA especially in capital offenses cannot be answered in every case, since a variety of scenarios for DNA transfer are possible. The aim of this study was to investigate whether DNA traces could be distributed by cleaning an object. For this purpose, a large table surface and fabric piece were artificially provided with skin contact traces and body fluids (saliva and blood) in two series of experiments and then wiped off with water or with soap water (218 samples in total). These experiments resulted in a clear "carry over" of DNA traces especially for body fluid samples (100% of blood samples and 75% of saliva samples led to a complete profile). The results could be confirmed in a second experimental set-up with 384 samples using different cleaning agents and more intense cleaning actions. Even small amounts of 5-10 µl body fluid led to complete profiles in around 45% of the samples, while 20 µl led to nearly 65% complete profiles. A strong impact of the amount of traces and the chosen surface could be demonstrated, while the active component of the cleaning agent seemed to be of less influence with the explicit exception of chloric agents which rendered almost everything completely DNA-free. In summary, a distribution of DNA traces by wiping or scrubbing an object could be clearly proven.

Occupational asthma caused by peracetic acid-hydrogen peroxide mixture.

BACKGROUND: Healthcare practice in the UK has moved away from using aldehyde disinfectants for the decontamination of endoscopes, in part due to the risk of respiratory sensitization. Peracetic acid (PAA) in combination with hydrogen peroxide (HP) is a commonly used alternative. AIM: We describe a case of occupational asthma (OA) diagnosed at our specialist occupational lung disease clinic and caused by occupational exposure to PAA-HP mixture, used as a disinfectant in an endoscope washer-disinfector machine. CASE REPORT: A 48-year-old man employed as a mycologist and environmental microbiologist at a Birmingham city hospital, UK, presented following an acute exposure to PAA-HP mixture causing lacrimation, burning optic pain and headache. He had also experienced symptoms suggestive of OA for the preceding 10 months, and the diagnosis was confirmed through OASYS analysis of serial peak expiratory flow measurements. He had been exposed to PAA-HP mixture whilst working in the endoscopy department for 12 months prior to the acute episode, and a subsequent specific inhalation challenge test was positive with a late asthmatic response to PAA-HP mixture. CONCLUSION: This case provides evidence for a sensitization mechanism in OA caused by PAA-HP mixture.

Fragrance allergens in household detergents.

Consumers are confronted with a large number of fragrance allergens from various sources. Until now, the discussion of exposure sources has mainly addressed cosmetic products and neglected other scented products in households. For the first time, fragrance allergens were evaluated in a complete set of detergents in households. In 131 households, we investigated the prevalence of detergents and searched their lists of ingredients for 26 fragrance allergens liable to be indicated on products according to the European Detergents Regulations. On the ingredient lists of 1447 products, these 26 fragrance substances were named almost 2000 times, most often limonene, linalool and hexyl cinnamal. Benzyl salicylate was used frequently in all-purpose cleaners. Linalool and limonene, hexyl cinnamal and butylphenyl methylpropional and citronellol and linalool co-occurred most often together in products. Fragrance allergens co-occurring together most frequently within households were eugenol, coumarin and cinnamyl alcohol. The study shows that detergents could play a relevant role for the exposure of consumers towards fragrance allergens and that they should not be underestimated as an exposure source during the exposure assessment.

The Effect of Cleaning Solutions on a Denture Base Material: Elimination of Candida albicans and Alteration of Physical Properties.

PURPOSE: To evaluate the antimicrobial efficiency of three cleaning solutions and their effect on the physical properties of a denture base material. MATERIALS AND METHODS: A heat-cured polymethyl-methacrylate (PMMA) denture base material (Meliodent) and three cleaning solutions (alkaline-peroxide, 30 minutes; 1% sodium-hypochlorite, 10 minutes; and 0.1% polymeric-guanidine solution, 5 minutes) were used. For antifungal activity test, 40 disc-shaped specimens were fabricated and allocated into a control group (distilled water) and 3 experimental groups (n = 10) according to the cleaning solutions. Antifungal activity against Candida albicans (ATCC 2091) was assessed with colony-forming units. An additional 40 rectangular plate specimens were fabricated for mechanical tests. Ten specimens were kept intact to be used as the control group for flexural strength test. The remaining 30 specimens were distributed into three groups according to the cleaning solutions. The surface roughness and Vickers hardness of the specimens were consecutively measured after 48 hours of water storage at 37 ± 2°C (t0), two disinfection cycles (t1), and 7 days of storage (t2) in one of the solutions. Finally, all 40 rectangular specimens were subjected to flexural strength test. Data were analyzed with Kruskal-Wallis test for antifungal activity, ANOVA for flexural strength test, and analysis of covariance for surface roughness and hardness tests. Significance was set at 0.05. RESULTS: The antifungal activities of polymeric guanidine and sodium hypochlorite were comparable to each other and significantly higher than alkaline peroxide (p < 0.05). The changes in the surface roughness of the specimens were statistically comparable among the cleaning solutions and time periods (p > 0.05); however, the decrease in the Vickers hardness of the specimens stored in sodium hypochlorite was significantly higher from t0 to t1 and t0 to t2 (p < 0.05) than other groups, resulting in comparable hardness changes. The flexural strengths of all groups were comparable with the control after t2 (p > 0.05). CONCLUSION: The use of polymeric guanidine disinfectant solution could be an alternative method for cleaning PMMA denture base materials.

Quantitative risk assessment of the aggregate dermal exposure to the sensitizing fragrance geraniol in personal care products and household cleaning agents.

A quantitative risk assessment was performed to establish if consumers are at risk for being dermally sensitized by the fragrance geraniol. Aggregate dermal exposure to geraniol was estimated using the Probabilistic Aggregate Consumer Exposure Model, containing data on the use of personal care products and household cleaning agents. Consumer exposure to geraniol via personal care products appeared to be higher than via household cleaning agents. The hands were the body parts receiving the highest exposure to geraniol. Dermal sensitization studies were assessed to derive the point of departure needed for the estimation of the Acceptable Exposure Level (AEL). Two concentrations were derived, one based on human studies and the other from dose-response analysis of the available murine local lymph node assay data. The aggregate dermal exposure assessment resulted in body part specific median exposures up to 0.041 µg/cm(2) (highest exposure 102 µg/cm(2)) for hands. Comparing the exposure to the lowest AEL (55 µg/cm(2)), shows that a range of 0.02-0.86% of the population may have an aggregated exposure which exceeds the AEL. Furthermore, it is demonstrated that personal care products contribute more to the consumer's geraniol exposure compared to household cleaning agents.

Airway Diseases Related to the Use of Cleaning Agents in Occupational Settings.

Exposure to disinfectants and cleaning products (DCPs) is now a well-established risk factor for work-related asthma (WRA). However, questions remain on the specific causal agents and pathophysiological mechanisms. Few studies have also reported an association between DCPs and rhinitis or chronic obstructive pulmonary disease. This review discusses the recent evidence pertaining to airway diseases attributable to occupational exposure to DCPs. In contrast to other agents, the incidence of WRA due to DCPs has increased over time. The use of DCPs in spray form has clearly been identified as an added risk factor. The mechanisms for WRA associated with DCPs remain poorly studied; however, both allergic and nonallergic responses have been described, with irritant mechanisms thought to play a major role. An early diagnostic workup based on clinical assessment accompanied by evaluation of lung function and immunological and airway inflammatory markers is important to guide optimal care and exposure avoidance to the implicated agent. Future research should focus on the effects of "green" products, pathophysiological mechanisms, and quantitative exposure assessment including the use of barcode-based methods to identify specific agents. There is an urgent need to strengthen preventive measures and interventions to reduce the burden of airway diseases associated with DCPs.

Effects of Alkaline Cleaning Agents on the Long-Term Performance and Aging of Polyethersulfone Ultrafiltration Membranes Applied for Treatment of Car Wash Wastewater.

The commercial ultrafiltration polyethersulfone (PES) membranes (10 and 100 kDa) blended with polyvinylpyrrolidone (PVP) were applied for the filtration of car wash wastewater. Periodical membrane rinsing with water did not prevent fouling and a decrease in permeate flux was observed. Fouling was reduced by washing the membranes with cleaning agents, which are used in car washes to clean wheels and remove insects. In addition to surfactants, these agents contain NaOH, hence the pH value of cleaning solutions was over 11. Long-term contact with such solutions resulted in the removal of PVP from the membrane matrix and an increase in pore size. The PES membranes were soaked in an alkaline solution (pH = 11.5) for 20 months, after which the 200 kDa dextran rejection decreased from 95% to 80%. To compare with the static degradation conditions, 8 weeks of alkaline agent filtration was realized, after which the dextran (200 kDa) rejection decreased below 50%. This indicated that the cross-flow of alkaline agents can accelerate the removal of components building the membrane matrix. Despite membrane degradation, the separation efficiency (the rejection of chemical oxygen demand-COD, turbidity, and surfactants) during the treatment of synthetic car wash wastewater was similar to that obtained for pristine membranes.

Fatal exposure to quaternary ammonium disinfectant in 2 dogs.

OBJECTIVE: To describe the clinical course and necropsy findings of 2 dogs after exposure to quaternary ammonium disinfectants. CASE SERIES SUMMARY: Two dogs were treated after accidental exposure to quaternary ammonium disinfectants in kennel settings. Both dogs developed ulcerative upper gastrointestinal lesions, severe pulmonary disease, and skin lesions. In the second case, the skin lesions were severe and became necrotizing. Both patients were ultimately euthanized due to severity of illness and lack of response to therapy. NEW OR UNIQUE INFORMATION PROVIDED: Quaternary ammonium compounds are commonly used as disinfectants in veterinary hospitals and boarding facilities. This is the first report detailing presentation, clinical picture, case management, and necropsy findings in dogs exposed to these chemicals. Awareness of the severity of these poisonings and the potential for fatal outcome is imperative.

Recovery of cleaning agents from Clean-In-Place (CIP) wastewater using nanofiltration (NF) and direct contact membrane distillation (DCMD).

Increasing concerns about freshwater sources necessitate the management of wastewater, such as the wastewater generated from Clean-in-Place (CIP) operations. In this investigation, a membrane system composed of nanofiltration (NF) and direct contact membrane distillation (DCMD) was proposed to manage model dairy CIP wastewater that contained NaOH as an alkaline cleaning agent. During the NF step, prefiltration by a 4 kDa membrane or a 4 kDa membrane followed by a 200 Da membrane (4 kDa/200 Da) was used to remove the whey protein and lactose. With these two membranes in series of NF, the protein concentration was reduced by 92.4% and the lactose content was reduced to a non-detectable level when compared to the model CIP wastewater. Before concentrating the permeates from NF steps, three DCMD membranes (FR, Solupor, and ST) with different characteristics were evaluated to manage the NF permeates from 4 kDa or 200 Da NF. An increase in the feed temperature from 40 °C to 60 °C resulted in an increase in the water flux during DCMD operation, except for FR. In addition, it was found that ST generated the highest water flux when compared to the other membranes. Using ST and a feed temperature of 60 °C, the permeates from 4 kDa or 4 kDa/200 Da were continuously concentrated for 7 h with DCMD. During this concentration, there was no significant decline in flux. The cleaning effectiveness of the cleaning agent (NaOH) recovered by NF and DCMD was compared with a fresh cleaning solution using quartz crystal microbalance with dissipation (QCM-D). It was found that the cleaning agents recovered by 4 kDa/200 Da NF presented a statistically identical cleaning rate compared to fresh NaOH. This research highlights the potential of NF and DCMD to regenerate alkaline cleaning agents, while reclaiming water from dairy CIP wastewater.

Characterization of Exposure to Cleaning Agents Among Health Workers in Two Southern African Tertiary Hospitals.

BACKGROUND: Whilst cleaning agents are commonly used in workplaces and homes, health workers (HWs) are at increased risk of exposure to significantly higher concentrations used to prevent healthcare-associated infections. Exposure assessment has been challenging partly because many are used simultaneously resulting in complex airborne exposures with various chemicals requiring different sampling techniques. The main objective of this study was to characterize exposures of HWs to various cleaning agents in two tertiary academic hospitals in Southern Africa. METHODS: A cross-sectional study of HWs was conducted in two tertiary hospitals in South Africa (SAH) and Tanzania (TAH). Exposure assessment involved systematic workplace observations, interviews with key personnel, passive personal environmental sampling for aldehydes (ortho-phthalaldehyde-OPA, glutaraldehyde and formaldehyde), and biomonitoring for chlorhexidine. RESULTS: Overall, 269 samples were collected from SAH, with 62 (23%) collected from HWs that used OPA on the day of monitoring. OPA was detectable in 6 (2%) of all samples analysed, all of which were collected in the gastrointestinal unit of the SAH. Overall, department, job title, individual HW use of OPA and duration of OPA use were the important predictors of OPA exposure. Formaldehyde was detectable in 103 (38%) samples (GM = 0.0025 ppm; range: <0.0030 to 0.0270). Formaldehyde levels were below the ACGIH TLV-TWA (0.1 ppm). While individual HW use and duration of formaldehyde use were not associated with formaldehyde exposure, working in an ear, nose, and throat ward was positively associated with detectable exposures (P-value = 0.002). Glutaraldehyde was not detected in samples from the SAH. In the preliminary sampling conducted in the TAH, glutaraldehyde was detectable in 8 (73%) of the 11 samples collected (GM = 0.003 ppm; range: <0.002 to 0.028). Glutaraldehyde levels were lower than the ACGIH's TLV-Ceiling Limit of 0.05 ppm. p-chloroaniline was detectable in 13 (4%) of the 336 urine samples (GM = 0.02 ng/ml range: <1.00 to 25.80). CONCLUSION: The study concluded that detectable exposures to OPA were isolated to certain departments and were dependent on the dedicated use of OPA by the HW being monitored. In contrast, low-level formaldehyde exposures were present throughout the hospital. There is a need for more sensitive exposure assessment techniques for chlorhexidine given its widespread use in the health sector.