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.

Analytical techniques for monitoring of toluene and xylene exposure biomarkers hippuric acid and methylhippuric acid in human urine samples

Quantification of hippuric acid and methylhippuric acid in human urine matrices provides information on the toluene and xylene exposure conditions. High performance liquid chromatography coupled with UV detection is the preferable technique for hippuric acid and methylhippuric acid detection in human urine. This study was conducted to present analytical techniques developed for monitoring of hippuric acid and methylhippuric acid in human urine matrices during 2016-2021.

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.

Personal NO2 and Volatile Organic Compounds Exposure Levels are Associated with Markers of Cardiovascular Risk in Women in the Cape Town Region of South Africa

Exposure to ambient NO2 and benzene, toluene ethyl-benzene and m+p- and o-xylenes (BTEX) is associated with adverse cardiovascular effects, but limited information is available on the effects of personal exposure to these compounds in South African populations. This 6-month follow-up study aims to determine 7-day personal ambient NO2 and BTEX exposure levels via compact passive diffusion samplers in female participants from Cape Town, and investigate whether exposure levels are associated with cardiovascular risk markers. Overall, the measured air pollutant exposure levels were lower compared to international standards. NO2 was positively associated with systolic and diastolic blood pressure (SBP and DBP), and inversely associated with the central retinal venular equivalent (CRVE) and mean baseline brachial artery diameter. o-xylene was associated with DBP and benzene was strongly associated with carotid intima media thickness (cIMT). Our findings showed that personal air pollution exposure, even at relatively low levels, was associated with several markers of cardiovascular risk in women residing in the Cape Town region.