Summer and winter variations of BTEX concentrations in an oil refinery complex and health risk assessment based on Monte-Carlo simulations

The summer and winter concentrations of BTEX pollutants were investigated in various workplaces of an oil Refinery, Iran. In total 252 air samples from the breathing zones of the following employees were collected: supervisors, safetymen, repairmen, site men, and all workers. Carcinogenic and non-carcinogenic risk values were calculated based on the USEPA methodology using Monte Carlo simulations. BTEX concentrations were higher in the summer than in the winter season for all workstations, especially for toluene and ethylbenzene. The mean values of exposure to benzene for repairmen and site men were higher than threshold limit value of 1.60 mg/m3 for both seasons. Non-carcinogenic risk (HQ) values calculated for summer season for benzene, ethylbenzene, and xylene in all workstations, as well as for toluene for repairmen and site men exceeded acceptable level of 1. In winter season the mean HQ values for benzene and xylene in all workstations, for toluene for repairmen and site men, and for ethylbenzene for supervisors, repairmen, and site men were also > 1. For all workstations definite carcinogenic risk was indicated as calculated LCR values for benzene and ethylbenzene exposure were higher than 1 × 10-4 in both summer and winter seasons.

Occupational exposure to BTEX and styrene in West Asian countries: a brief review of current state and limits

The aim of introducing occupational exposure limits (OELs) is to use them as a risk management tool in order to protect workers' health and well-being against harmful agents at the workplace. In this review we identify OELs for benzene, toluene, ethylbenzene, xylene (BTEX), and styrene concentrations in air and assess occupational exposure to these compounds through a systematic literature search of publications published in West Asian countries from 1980 to 2021. OELs for BTEX and styrene have been set in Iran and Turkey to levels similar to those in European countries and the US. The search yielded 49 full-text articles that cover studies of exposure assessment in six countries, but most (n=40) regard Iran. Average occupational exposure to benzene of workers in oil-related industries is higher than recommended OEL, while average occupational exposure to other compounds is lower than local OELs (where they exist). Currently, information about levels of occupational exposure to BTEX and styrene is insufficient in West Asian countries, which should be remedied through OEL regulation and application. Furthermore, coherent research is also needed to determine actual levels of occupational exposure, dose-responses, and the economic and technical capacity of local industries to address current issues.

Evaluation of Blood Lead Levels and Their Effects on Hematological Parameters and Renal Function in Iranian Lead Mine Workers

Background: Lead toxicity has become a growing health concern in countries such as Iran. However, little information is available on the assessment and evaluation of the health effects of lead exposure in mine workers. Objectives: The present study assessed the occupational exposure to lead and examine the association of blood lead (PbB) levels with hematological and kidney function parameters in mine workers. Methods: In this matched case-control study, the level of PbB was measured in 100 workers (70 exposed and 30 non-exposed), and then its relationship was evaluated with complete blood count (CBC) parameters, zinc protoporphyrin (ZPP), urea, blood creatinine levels, urinary δ-aminolevulinic acid (ALA), coproporphyrin, and creatinine levels. Results: The results showed a linear and significant relationship between the PbB level and B-ZPP, U-ALA, U-coproporphyrin, and U-creatinine levels in states of PbB levels > 20 μg/dL in a time and dose-dependent manner. A significant relationship was observed between the PbB level and the years of occupational exposure to lead and the B-urea level (P-value < 0.03). Conclusions: Chronic occupational exposure to lead decreased hematocrit, RDW-CV, MCV, MCH, and HGB values but did not significantly change RBC counts. Therefore, a regular assessment of routine blood parameters (such as CBC and ZPP) and renal function indices can be effectively used to monitor the toxic effects of lead exposure.