Temporal decline in serum PFAS concentrations among metropolitan firefighters: Longitudinal study on post-exposure changes following PFAS foam cessation.

Firefighters are at a high risk of exposure to per- and polyfluoroalkyl substances (PFAS) due to their frequent use of PFAS-containing foams in training and emergency situations. This longitudinal study aimed to investigate the changes in serum PFAS levels among firefighters following cessation of their exposure to PFAS-containing foams. The study involved 130 firefighters from the South Australian Metropolitan Fire Services (SAMFS), and serum samples were collected at two time points: baseline in 2018-19 and follow-up in 2021-22. Along with the collection of samples, a survey questionnaire was administered to gather information on firefighters' employment and demographic characteristics. Regression models were employed to assess the association between these factors and the outcome variable (annual percentage change in serum PFAS concentration). The results indicated a decline in serum PFAS concentrations over time, with the main contaminants being perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA). The median and Interquartile Range (IQR) of total PFAS (∑PFAS) concentration reduced from 21.5 ng/ml (IQR: 11 to 53 ng/ml) at baseline to 15 ng/ml (IQR: 8 to 33 ng/ml) at follow-up. On average, there was an annual reduction of 13%, 7%, and 4.4% in serum concentrations of PFOS, PFHxS, and PFOA, respectively. Firefighters under the age of 55, those who used PFAS in the past ten years, or those who had little to no frequency of PFAS exposure in their previous employment, encountered a significantly higher annual percentage reduction (P < 0.05) in both ∑PFAS and PFOS concentrations. None of the independent variables analysed could significantly predict the annual percentage change in PFOA and PFHxS. This study provides evidence for a declining temporal trend in serum PFAS concentrations among metropolitan firefighters following workplace interventions that involved the removal of PFAS-containing foams.

Determinants of undernutrition among children aged 6-59 months during the COVID-19 pandemic: A hospital-based cross-sectional study in Ethiopia.

Background: The public health problem of undernutrition is common in Ethiopia, particularly among children aged 6-59 months. However, determinants of undernutrition among children in this age group are not well investigated particularly within the context of COVID-19 pandemic. This study was, therefore, designed to assess the magnitude and determinants of undernutrition among children aged 6-59 months at Tirunesh Beijing general hospital, Ethiopia. Methods and materials: An institutional-based cross-sectional study was conducted involving 283 children aged 6-59 months in March 2022. The data were collected using structured questionnaire and anthropometric measurements. Undernutrition was defined as a Z-score value of weight for height (WFH), height-for-age (HFA), and weight-for-age (WFA) <2SD as calculated by the world health organization plus software. A multivariable logistic regression model was used to identify the independent factors associated with undernutrition. p-values less than 0.05 were considered statistically significant. Results: The response rate in this study was 97.9%. The overall magnitude of undernutrition was 34.3%, of which 21.2%, 12.7%, and 9.5% were stunted, underweight, and wasted, respectively. Occupation of mothers [AOR = 13.64, 95% CI (4.21-14.77)], amount of meal [AOR = 14.68, 95% CI (4.09-52.81)], feeding by caregivers [AOR = 8.96, 95% CI (2.81-18.60)], and breastfeeding [AOR = 0.06, 95% CI (0.02-0.22)] were significant predictors of undernutrition. Conclusions: The prevalence of undernutrition among children under the age of five remains high. Therefore, promoting breastfeeding and motivating children to feed adequate amount of meal are recommended. Besides, counseling and/or guiding caregivers on how to feed children shall be suggested. The findings could help inform the design and prioritization of effective intervention strategies at early life stage.

Food grown on fire stations as a potential pathway for firefighters' exposure to per- and poly-fluoroalkyl substances (PFAS).

Human exposure to per- and polyfluoroalkyl substances also known as PFAS is an ongoing occupational and environmental health problem. This study seeks to characterise multiple pathways for firefighters' exposure to PFAS. PFAS were analysed in 688 environmental samples such as eggs, fruits, vegetables, dust, soil, surface swabs, appliance washes and water obtained from fire stations. Relevant exposure pathways were identified and daily intake levels were estimated using PFAS concentrations and exposure factors relevant to firefighters. Five PFAS including perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), 6:2 fluorotelomer sulfonate (6:2 FTS), and 8:2 fluorotelomer sulfonic acid (8:2 FTS) were frequently detected in the samples. Based on the median concentrations in each sample type, PFOS was the most abundant contaminant in eggs (80%), fruits (52%), dust (81%), surface swab (66%), soil (83%) and appliance wash (31%) samples. On the other hand, PFHxS was most abundant in vegetables (77%) and 8:2 FTS in water (58%). The intake estimation results show that dietary exposure from ingestion of foods produced on fire stations was the predominant exposure pathway, representing 82% and 62% of firefighters' total PFAS intake under typical and worst-case exposure scenarios, respectively. Incidental ingestion and dermal absorption of PFAS in dust contributed 15% for typical and 34% for worst-case exposure scenarios. The relative contributions from incidental ingestion and dermal absorption of PFAS in soil and appliance washes were insignificant. Overall, the study identifies multiple exposure pathways relevant to career firefighters including consumption of food grown on fire stations, which has not previously been recognised within the occupational exposure context. The results suggest exposure control strategies that target foods produced on fire stations could substantially reduce firefighters' exposure to PFAS.