Probabilistic health risk assessment of occupational exposure to crystalline silica in an iron foundry in Urmia, Iran

Contributions of Synthetic Chemicals to Autoimmune Disease Development and Occurrence

PURPOSE OF REVIEW

Exposure to many synthetic chemicals has been linked to a variety of adverse human health effects, including autoimmune diseases. In this scoping review, we summarize recent evidence detailing the effects of synthetic environmental chemicals on autoimmune diseases and highlight current research gaps and recommendations for future studies.

RECENT FINDINGS

We identified 68 recent publications related to environmental chemical exposures and autoimmune diseases. Most studies evaluated exposure to persistent environmental chemicals and autoimmune conditions including rheumatoid arthritis (RA), systemic lupus (SLE), systemic sclerosis (SSc), and ulcerative colitis (UC) and Crohn's disease. Results of recent original research studies were mixed, and available data for some exposure-outcome associations were particularly limited. PFAS and autoimmune inflammatory bowel diseases (UC and CD) and pesticides and RA appeared to be the most frequently studied exposure-outcome associations among recent publications, despite a historical research focus on solvents. Recent studies have provided additional evidence for the associations of exposure to synthetic chemicals with certain autoimmune conditions. However, impacts on other autoimmune outcomes, particularly less prevalent conditions, remain unclear. Owing to the ubiquitous nature of many of these exposures and their potential impacts on autoimmune risk, additional studies are needed to better evaluate these relationships, particularly for understudied autoimmune conditions. Future research should include larger longitudinal studies and studies among more diverse populations to elucidate the temporal relationships between exposure-outcome pairs and to identify potential population subgroups that may be more adversely impacted by immune modulation caused by exposure to these chemicals.

Monte Carlo-based probabilistic risk assessment for cement workers exposed to heavy metals in cement dust

This study assessed the carcinogenic and non-carcinogenic health risks of cement plant workers exposed to chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) in cement dust using a probabilistic approach. Air samples were collected according to NIOSH 7900 and OSHA ID-121 methods and analyzed by an graphite furnace atomic absorption spectrometer. The EPA inhalation risk assessment model and Monte Carlo simulation were utilized to assess the health risks. Sensitivity analysis was used to determine the influencing parameters on health risk. The average concentrations of As and Pb exceeded the occupational exposure limit (OEL), reaching a maximum of 3.4 and 1.7 times the OEL, respectively, in the cement mill. Individual metals' cancer risk exceeded the 1E-4 threshold in ascending order of Cd < As < Cr. The mean cancer risk of Cr ranged from 835E-4 (in raw mill) to 2870E-4 (in pre-heater and kiln). Except for Cd, the non-cancer risk of metals exceeded the standard (hazard index, HQ = 1) in the ascending order of Pb < As < Cr. The mean HQ of Cr ranged from 162.13 (in raw mill) to 558.73 (in pre-heater and kiln). After adjusting for control factors, the cancer and non-cancer risks remained over the respective recommended levels. Sensitivity analysis revealed that the concentration of Cr was the most influential parameter on both carcinogenic (78.5%) and non-carcinogenic (88.06%) risks. To protect the health of cement factory employees, it is recommended to minimize cement dust emissions, implement job rotation, and use raw materials with low levels of heavy metals.

Carcinogenic and non-carcinogenic risk of exposure to metal fume in different types of welding processes

The international agency for cancer research (IARC) has classified welding fumes as definitive carcinogens. The aim of the present study was to assess health risk due to exposure to welding fumes in different welding types. In this study, exposure to fumes of iron (Fe), chromium (Cr), and nickel (Ni) in the breathing zone air of 31 welder engaged in arc, argon and CO₂ welding was assessed. Carcinogenic and non-carcinogenic risk assessments due to exposure to fumes were performed using the method proposed by the Environmental Protection Agency (EPA) by Monte Carlo simulation. The results showed that in the CO₂ welding, concentration of Ni, Cr, and Fe was lower than the 8-h Time-Weighted Average Threshold Limit Value (TWA-TLV), recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). In argon welding, Cr and Fe concentrations were higher than the TWA-TLV. In arc welding, concentrations of Ni and Fe were more than the TWA-TLV. In addition, the risk of non-carcinogenicity due to exposure to Ni and Fe in all three types of welding was more than standard level (HQ>1). The results indicated that the welders are at health risk due to exposure to metal fumes. Preventive exposure control measures such as local ventilation need to be implemented in welding workplaces.