Chloroform exposure in air and water in Swedish indoor swimming pools-urine as a biomarker of occupational exposure.

INTRODUCTION: Disinfection by-products are produced in water disinfected with chlorine-based products. One such group is trihalomethanes, and chloroform is the most abundant trihalomethane in swimming pool areas. Chloroform can be absorbed by inhalation, ingestion, and dermal absorption, and is classified as possibly carcinogenic. AIM: To investigate if chloroform concentrations in air and water affect the chloroform concentration in urine samples of exposed swimming pool workers. METHODS: Workers from 5 adventure indoor swimming pools carried personal chloroform air samplers and provided up to 4 urine samples during one workday. Chloroform concentrations were analyzed with a linear mixed model analysis to investigate a possible correlation between air and urine concentrations. RESULTS: The geometric mean chloroform concentration was 11 µg/m3 in air and 0.009 µg/g creatinine in urine among individuals with ≤2 h at work, 0.023 µg/g creatinine among those with >2-5 working hours, and 0.026 µg/g creatinine in the group with >5-10 working hours. A risk of higher levels of chloroform in urine was associated with longer hours at work (≤2 h versus >5-10 h, odds ratio [OR] 2.04, 95% confidence interval [CI] 1.25-3.34), personal chloroform concentrations in air (≤17.00 µg/m3 versus >28.00 µg/m3, OR 9.23, 95% CI 3.68-23.13) and working at least half the working day near the swimming pools (OR 3.16, 95% CI 1.33-7.55). Executing work tasks in the swimming pool water was not associated with higher chloroform concentrations in urine compared to only working on land (OR 0.82, 95% CI 0.27-2.45). CONCLUSION: There is an accumulation of chloroform concentrations in urine during a workday and a correlation between personal air and urine concentrations of chloroform among workers in Swedish indoor swimming pools.

Occupational Exposure to Trichloramine and Endotoxins: Adverse Health Effects Among Personnel in Adventure and Rehabilitation Swimming Pool Facilities.

OBJECTIVE: To study occupational exposure totrichloramine and endotoxins in air at adventure and rehabilitation swimming pool facilities from an adverse health effects perspective. METHODS: Air concentrations of trichloramine and endotoxins were measured in five adventure and 10 rehabilitation facilities. Respiratory and ocular symptoms were self-reported, and spirometry and fraction of exhaled nitric oxide (FEno) were measured. RESULTS: Compared to rehabilitation facilities, the mean trichloramine concentrations in the adventure facilities were higher, both personal (80 µg/m3 (n  = 41) vs 19 µg/m3 (n = 21)) and stationary (183 µg/m3 (n = 51) vs 23 µg/m3 (n = 32)), with higher frequency of ocular and respiratory symptoms. Low stationary endotoxin levels (<0.64 to 25 EU/m3) were found, compared to the reference value (90 EU/m3). CONCLUSIONS: Higher trichloramine concentrations in air and more ocular and respiratory symptoms in adventure facilities call for adequate occupational exposure limits.

Introducing a new design of digital tool to increase vibration risk assessments: challenges with education-based interventions.

Objectives. This study aimed to investigate whether introducing a digital risk assessment tool, the Swedish National Vibration Database, would increase the number of risk assessments on hand-arm and whole-body vibration. Employer and safety representatives from companies where vibration exposure is common were invited. Methods. Of the 2953 invited companies, 1916 were selected for educational intervention and the remaining 1037 companies served as a control group with no intervention. For the educational intervention, participating companies were further divided into two groups (group A, n = 26; group B, n = 47) that both received information regarding risk assessment, but group B was also informed about the digital tool. Both groups answered a questionnaire on risk assessment before the intervention and at the follow-up, 6 months later; the control group received the same questionnaire but no education (group C, n = 22). Results. Of the invited companies, only 2% chose to participate and 7% at follow-up. Seventy-eight percent of the participants had made some kind of risk assessment of vibration at follow-up. Conclusion. Due to the low participation rate among invited companies, this study is not able to draw any conclusions on whether the digital tool can be used to increase the number of risk assessments.

Occupational exposure to trichloramine and trihalomethanes: adverse health effects among personnel in habilitation and rehabilitation swimming pools.

Personnel in swimming pool facilities typically experience ocular, nasal, and respiratory symptoms due to water chlorination and consequent exposure to disinfection by-products in the air. The aim of the study was to investigate exposure to trichloramine and trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) from the perspective of adverse health effects on the personnel at Swedish habilitation and rehabilitation swimming pools. The study included 10 habilitation and rehabilitation swimming pool facilities in nine Swedish cities. The study population comprised 24 exposed swimming pool workers and 50 unexposed office workers. Personal and stationary measurements of trichloramine and trihalomethanes in air were performed at all the facilities. Questionnaires were distributed to exposed workers and referents. Spirometry, fraction of exhaled nitric oxide (FENO), and peak expiratory flow (PEF) were measured. Personal and stationary measurements yielded trichloramine levels of 1-76 µg/m3 (average: 19 µg/m3) and 1-140 µg/m3 (average: 23 µg/m3), respectively. A slightly higher, but not significant, prevalence of reported eye- and throat-related symptoms occurred among the exposed workers than among the referents. A significantly increased risk of at least one ocular symptom was attributed to trichloramine exposure above the median (20 µg/m3). Lung function (FVC and FEV1) was in the normal range according to the Swedish reference materials, and no significant change in lung function before and after shift could be established between the groups. Average FENO values were in the normal range in both groups, but the difference in the values between the exposed workers and referents showed a significant increase after shift. Hourly registered PEF values during the day of the investigation did not show any unusual individual variability. In conclusion, the increased risk of developing at least one ocular symptom at personal trichloramine concentrations over 20 µg/m3 combined with an increase in the difference in FENO during the work shift of the exposed workers should not be neglected as an increased risk of respiratory inflammation in the habilitation and rehabilitation swimming pool environment.

Respiratory and Ocular Symptoms Among Employees at Swedish Indoor Swimming Pools.

BACKGROUND: This study investigated trichloramine exposure and prevalence of respiratory and ocular symptoms among Swedish indoor swimming pool workers. METHODS: Questionnaires were distributed to pool workers and referents. Lung function and fraction of exhaled nitric oxide (FeNO) were measured before and after work. Exposure to trichloramine and trihalomethanes was measured over work shifts. RESULTS: The mean personal trichloramine exposure was 36 µg/m. Significantly more exposed workers reported ocular and nasal symptoms. There were significant differences between groups in FeNO change following work, with exposed showing increased FeNO, which grew when analyses included only nonsmokers. CONCLUSIONS: The findings indicate that indoor swimming pool environments may have irritating effects on mucous membranes. FeNO data also indicate an inflammatory effect on central airways, but the clinical relevance is unclear. Low trichloramine levels found in this study were not associated with health effects.

Occupational Exposure to Trichloramine and Trihalomethanes in Swedish Indoor Swimming Pools: Evaluation of Personal and Stationary Monitoring.

INTRODUCTION: Chlorination is a method commonly used to keep indoor swimming pool water free from pathogens. However, chlorination of swimming pools produces several potentially hazardous by-products as the chlorine reacts with nitrogen containing organic matter. Up till now, exposure assessments in indoor swimming pools have relied on stationary measurements at the poolside, used as a proxy for personal exposure. However, measurements at fixed locations are known to differ from personal exposure. METHODS: Eight public swimming pool facilities in four Swedish cities were included in this survey. Personal and stationary sampling was performed during day or evening shift. Samplers were placed at different fixed positions around the pool facilities, at ~1.5 m above the floor level and 0-1 m from the poolside. In total, 52 personal and 110 stationary samples of trichloramine and 51 personal and 109 stationary samples of trihalomethanes, were collected. RESULTS: The average concentration of trichloramine for personal sampling was 71 µg m(-3), ranging from 1 to 240 µg m(-3) and for stationary samples 179 µg m(-3), ranging from 1 to 640 µg m(-3). The air concentrations of chloroform were well below the occupational exposure limit (OEL). For the linear regression analysis and prediction of personal exposure to trichloramine from stationary sampling, only data from personal that spent >50% of their workday in the pool area were included. The linear regression analysis showed a correlation coefficient (r2) of 0.693 and a significant regression coefficient ß of 0.621; (95% CI = 0.329-0.912, P = 0.001). CONCLUSION: The trichloramine exposure levels determined in this study were well below the recommended air concentration level of 500 µg m(-3); a WHO reference value based on stationary sampling. Our regression data suggest a relation between personal exposure and area sampling of 1:2, implying an OEL of 250 µg m(-3) based on personal sampling.

ER stress induces epithelial differentiation in the mouse oesophagus.

OBJECTIVE: Stress in the endoplasmic reticulum (ER) leads to activation of the unfolded protein response (UPR). Xbp1, a key component of the UPR has recently been linked to the risk of developing oesophageal squamous cell carcinoma, suggesting an important role for the UPR in the oesophageal epithelium. Here we examined the role of ER stress and the UPR in oesophageal epithelial homoeostasis. DESIGN: We examined the expression of components of the UPR in the oesophageal epithelium. We used a pharmacological approach and a genetic approach to examine the effects of ER stress in vivo in the mouse oesophagus. The oesophagus of these mice was examined using immunohistochemistry and real-time reverse transcription (RT)-PCR. RESULTS: Components of the UPR were heterogeneously expressed in the basal layer of the epithelium. Induction of ER stress by 24-h treatment with thapsigargin resulted in depletion of proliferating cells in the basal layer of the oesophagus and induced differentiation. We next activated the UPR by inducible deletion of the major ER chaperone Grp78 in Ah1Cre-Rosa26-LacZ-Grp78(-/-) mice in which mutant cells could be traced by expression of LacZ. In these mice LacZ-positive mutant cells in the basal layer lost their proliferative capacity, migrated towards the oesophageal lumen and were replaced by LacZ-negative non-mutant cells. We observed no apoptosis in mutant cells. CONCLUSIONS: These results show that ER stress induces epithelial differentiation in precursor cells in the oesophageal epithelium. This UPR induced differentiation may serve as a quality control mechanism that protects against oesophageal cancer development.

Hedgehog signaling and maintenance of homeostasis in the intestinal epithelium.

Homeostasis of the rapidly renewing intestinal epithelium depends on a balance between cell proliferation and loss. Indian hedgehog (Ihh) acts as a negative feedback signal in this dynamic equilibrium. We discuss recent evidence that Ihh may be one of the key epithelial signals that indicates epithelial integrity to the underlying mesenchyme.

Role of EphA4 receptor signaling in thyroid development: regulation of folliculogenesis and propagation of the C-cell lineage.

Transcriptome analysis revealed that the tyrosine kinase receptor EphA4 is enriched in the thyroid bud in mouse embryos. We used heterozygous EphA4-EGFP knock-in mice in which enhanced green fluorescent protein (EGFP) replaced the intracellular receptor domain (EphA4(+/EGFP)) to localize EphA4 protein in thyroid primordial tissues. This showed that thyroid progenitors originating in the pharyngeal floor express EphA4 at all embryonic stages and when follicles are formed in late development. Also, the ultimobranchial bodies developed from the pharyngeal pouch endoderm express EphA4, but the ultimobranchial epithelium loses the EGFP signal before it merges with the median thyroid primordium. Embryonic C cells invading the thyroid are exclusively EphA4-negative. EphA4 expression continues in the adult thyroid. EphA4 knock-out mice and EphA4-EGFP homozygous mutants are euthyroid and have a normal thyroid anatomy but display subtle histological alterations regarding number, size, and shape of follicles. Of particular interest, the pattern of follicular abnormality differs between EphA4(-/-) and EphA4(EGFP/EGFP) thyroids. In addition, the number of C cells is reduced by >50% exclusively in animals lacking EphA4 forward signaling (EphA4(EGFP/EGFP)). Heterozygous EphA4 mutants have no apparent thyroid phenotype. We conclude that EphA4 is a novel regulator of thyroid morphogenesis that impacts on postnatal development of the two endocrine cell lineages of the differentiating gland. In this process both EphA4 forward signaling (in the follicular epithelium) and reverse signaling mediated by its cognate ligand(s) (A- and/or B-ephrins expressed in follicular cells and C cells, respectively) are probably functionally important.

Expression of Islet1 in thyroid development related to budding, migration, and fusion of primordia.

The LIM homeodomain transcription factor Isl1 was investigated in mouse thyroid organogenesis. All progenitor cells of the midline thyroid diverticulum and lateral primordia (ultimobranchial bodies) expressed Isl1. This pattern persisted until the growing anlagen fused at embryonic day (E) 13.5. In Isl1 null mutants thyroid progenitors expressing Nkx2.1 and Pax8 were readily specified in the anterior endoderm but the size of the thyroid rudiment was reduced. In late development, only immature C-cells expressed Isl1. In the adult gland the number of Isl1+ cells was small compared with cells expressing calcitonin. Analysis of microarray profiles indicated a higher level of Isl1 expression in medullary thyroid carcinomas than in tumors derived from follicular cells. Together, these findings suggest that Isl1 may be a novel regulator of thyroid development before terminal differentiation of the endocrine cell types. Isl1 is an embryonic C-cell precursor marker that may be relevant also in cancer developed from the mature C-cell.