Estimating airborne trichloramine levels in indoor swimming pools using the well-mixed box model.

Exposure to airborne disinfection by-products, especially trichloramine (TCA), could cause various occupational health effects in indoor swimming pools. However, TCA concentration measurements involve specialized analysis conducted in specific laboratories, which can result in significant costs and time constraints. As an alternative, modeling techniques for estimating exposures are promising in addressing these challenges. This study aims to predict airborne TCA concentrations in indoor swimming pools using a mathematical model, the well-mixed box model, found in the IHMOD tool, freely available on the American Industrial Hygiene Association website. The model's predictions are compared with TCA concentrations measured during various bather load scenarios. The research involved conducting 2-hr successive workplace measurements over 16- to 18-hr periods in four indoor swimming pools in Quebec, Canada. TCA concentrations were estimated using the well-mixed box model, assuming a homogeneous mixing of air within the swimming pool environment. A novel approach was developed to estimate the TCA generation rate from swimming pool water, incorporating the number of swimmers in the model. Average measured concentrations of TCA were 0.24, 0.26, 0.14, and 0.34 mg/m3 for swimming pools 1, 2, 3, and 4, respectively. The ratio of these measured average concentrations to their corresponding predicted values ranged from 0.51 to 1.30, 0.67 to 1.04, 0.57 to 1.14, and 0.68 to 1.49 for the respective swimming pools. In a worst-case scenario simulating the swimming pool at full capacity (maximum bathers allowed), TCA concentrations were estimated as 0.23, 0.36, 0.14, and 0.37 mg/m3 for swimming pools 1, 2, 3, and 4. Recalculated concentrations by adjusting the number of swimmers so as not to exceed the recommended occupational limit concentration of 0.35 mg/m3 gives a maximum number of swimmers of 63 and 335 instead of currently 80 and 424 for swimming pools 2 and 4, respectively. Similarly, for swimming pools 1 and 3, the maximum number of swimmers could be 173 and 398 (instead of the current 160 and 225, respectively). These results demonstrated that the model could be used to estimate and anticipate airborne TCA levels in indoor swimming pools across various scenarios.

Full-scale multisampling and empirical modeling of DBPs in water and air of indoor pools.

Disinfection by-products (DBPs) are formed in the water in swimming pools due to reactions between disinfectants (chlorine, bromine, ozone) and the organic matter introduced by bathers and supply water. High concentrations of DBPs are also reported in the air of indoor swimming pools. Based on a robust multisampling program, the levels and variations of DBPs in the air (trichloramine [TCAM] and trihalomethanes [THMs]) and water (THM) were assessed, as well as their precursors (total organic carbon, water temperature, pH, free, and total chlorine) and proxies (CO2 and relative humidity) in four indoor chlorinated swimming pools. High-frequency sampling was conducted during one high-attendance day for each pool. This study focused on parameters that are easy to measure in order to develop models for predicting levels of THMs and TCAM in the air. The results showed that the number of bathers had an important impact on the levels of THMs and TCAM, with a two-to-three-fold increase in air chloroform (up to 110 µg/m3) and a two-to-four-fold increase in TCAM (up to 0.52 mg/m3) shortly after pools opened. The results of this study for the first time showed that CO2 and relative humidity can serve as proxies for monitoring variations in airborne THMs and TCAM. Our results highlight the good predictive capacity of the developed models and their potential for use in day-to-day monitoring. This could help optimize and control DBPs formation in the air of indoor swimming pools and reduce contaminant exposure for both pool employees and users.

Temporal and spatial variations in the levels of prominent airborne disinfection by-products at four indoor swimming pools.

Exposure to airborne disinfection by-products, especially trichloramine and trichloromethane, may cause various adverse health effects for the workers and users of indoor swimming pools. This study aims to evaluate the spatial and temporal variations in trichloramine and trichloromethane concentrations within and between swimming pools. Workplace measurements were carried out at four indoor swimming pools in Quebec (Canada) during the cold season. To fully represent daily operating conditions, sampling started 2 hr before the swimming pool opened and continued until 2 hr after closing. To quantify trichloramine and trichloromethane concentrations, 304 air samples have been collected. Temperature, humidity, and CO2 were measured-simultaneously every 2 hr. The results showed that both trichloramine and trichloromethane concentrations varied significantly in time. The observed daily variations in trichloramine and trichloromethane concentrations suggest that the common practice of collecting a single 2-hr air sample does not represent daily pool trichloramine and trichloromethane contamination levels and, consequently, does not represent the true exposure and health risks for workers that are present for a full 8-hr shift. This study recommends a new 8-hr sampling strategy or a full-shift strategy using a cassette with three impregnated filters as a valid and cost-effective solution for comparing time-weighted average (TWA) concentrations to permissible trichloramine exposure limits.

Association between exposure to airborne trichloramine and health effects in indoor swimming pool workers.

OBJECTIVE: The main objective of this study was to comprehensively investigate the association between trichloramine (TCA) exposure and respiratory health effects in swimming pool workers. METHODOLOGY: In this study, air sampling was performed for TCA concentrations at fixed locations (static measurements) and on individual workers (personal measurements) in six indoor public swimming pools during periods of high swimmer attendance over the winter school break. Health effects were evaluated using questionnaires and fractional exhaled nitric oxide (FENO) tests performed before and after the working day. RESULTS: In these swimming pools, the environmental TCA concentration ranged from 0.11 to 0.88 mg/m³. Worker exposure ranged from 0.05 to 0.72 mg/m³ for personal measurements. Furthermore, in each swimming pool, the average worker exposure to TCA exceeded the recommended occupational exposure limit of 0.35 mg/m³. Personal TCA measurements were consistently lower than static measurements performed around the pool, with a reduction ranging from 21% to 49%. This can be explained by the time that the workers spend in the pool area, office, and break room. The most common respiratory health effects self-reported by the workers were coughing, shortness of breath, and sneezing with prevalence rates of 38%, 37%, and 35%, respectively. This study demonstrated an association between TCA exposure and eye irritation. Analysis of the FENO tests revealed that individuals with preexisting asthma or allergies exhibited sustained FENO elevation. CONCLUSION: The findings suggest that occupational exposure to TCA in indoor swimming pools is a matter of concern. Implementing and improving workplace safety measures is crucial for safeguarding the respiratory health of swimming pool workers.

Efficacy of olive leaves extract on the outcomes of hospitalized covid-19 patients: A randomized, triple-blinded clinical trial.

INTRODUCTION: Since the emergence of the novel coronavirus, herbal medicine has been considered a treatment for COVID-19 patients. This study was done to determine the efficacy of olive leaf extract on the outcomes of COVID-19 patients. MATERIALS AND METHODS: This randomized, triple-blinded clinical trial was conducted on hospitalized COVID-19 patients. Using block randomization, eligible patients were allocated to the following groups: intervention A received olive leaf extract (250 mg every 12 hours for five days), intervention B received olive leaf extract (500 mg every 12 hours for five days), and the control group received placebo (every 12 hours for five days). The outcomes (vital signs, laboratory tests, and length of hospitalization) were compared by group. RESULTS: Of the 150 patients randomized into groups, 141 completed the follow-up and were analyzed. On the fifth day of hospitalization, body temperature (MD=0.34, P<0.001), pulse rate (MD=5.42, P=0.016), respiratory rate (MD=1.66, P=0.001), ESR (MD=13.55, P<0.001), and CRP (MD=15.68, P<0.001) of intervention A were significantly lower than the control group, while oxygen saturation (MD= -1.81, P=0.001) of intervention A was significantly higher than the control group. Furthermore, body temperature (MD=0.30, P=0.001), pulse rate (MD=5.29, P=0.022), respiratory rate (MD=1.41, P=0.006), ESR (MD=14.79, P<0.001), and CRP (MD=16.28, P<0.001) of intervention B were significantly lower than the control group, while oxygen saturation (MD= -2.38, P<0.001) of intervention B was significantly higher than the control group. CONCLUSION: Olive leaf extract can improve the clinical status of the patients and decrease the length of hospitalization.

Comparison of sampling collection strategies for assessing airborne trichloramine levels in indoor swimming pools.

Since 1995, Hery's trichloramine sampling procedure has been widely used to determine trichloramine exposure in indoor swimming pools. This method consists of pumping air at a 1 L/min flow rate for 2 h through a Teflon prefilter and two quartz fiber filters. Modified Hery methods have been reported using different sampling pump flow rates and types of prefilters. It is possible that the prefilter type or sample collection pump flow rate influenced the results of these studies. This study is designed to evaluate the effects of different cassette assemblies and sampling flow rates on the levels of measured trichloramine. Laboratory tests were performed using a trichloramine production setup designed for this study. Workplace measurements were carried out at four indoor swimming pools. Different prefiltering strategies were used: no prefilter, glass prefilter or Teflon prefilter in the sampling cassette, and an original separable prefilter cassette is presented in this study. Laboratory tests indicated that at trichloramine concentrations higher than 1 mg/m3, the percentage of trichloramine captured on the first filter could be less than 75%, which demonstrated possible loss of the material during sampling. An investigation of the prefilter effect on the sampling strategy using different cassette assemblies revealed that using a separable cassette assembly prevented overestimations of trichloramine levels. Furthermore, there were no significant differences between trichloramine concentrations measured at flow rates (from 0.5 to 2 L/min) in swimming pools.

Nanoplastics-induced oxidative stress, antioxidant defense, and physiological response in exposed Wistar albino rats.

Nowadays, plastic pollution and in particular nano(micro)plastics is considered as an issue of global concern in environmental samples. The present work was conducted to clarify the oxidative stress of polystyrene nanoplastics (PS-NPs) exposure and physiological response of male Wistar rats. Animals were treated orally with PS-NPs at four doses (1, 3, 6, and10 mg/kg-day) for 5 weeks. Results demonstrated the accumulation of PS-NPs through whole body scanning and also a dose-dependent increase in the production of reactive oxygen species (ROS). Alterations in antioxidant responses including serum levels of catalase (CAT) and total glutathione content were noticed, but not superoxide dismutase (SOD), pointing towards the perturbation of redox state induced by exposure conditions. Biochemical parameters viz. glucose, cortisol, lipase, lactate, lactate dehydrogenase (LDH), alkaline phosphatase, gamma-glutamyl transpeptidase (GGT), triglycerides, and urea showed a significant increase, while total protein, albumin, and globulin levels showed an appreciable decline. The pattern of associations noticed with AChE activity and biochemical responses in our study suggests the possibility that a neurobehavioral effect or dysfunctions in energy metabolism may be the potential modes of action, possibly through stress response as well as liver function. Perturbations of creatinine and uric acid levels are indeed plausible biological explanations for the association with kidney dysfunction. Although we provided a new scientific clue for exploring the biological consequences of NPs which might induce effects such as oxidative stress relating to the induction of antioxidant enzymes, the results warrant additional research with a larger sample size.