Journal of School of Public Health and

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In this study, parameters affecting on SPE of trance trance muconic acid (t,t-MA), including sample pH, sample concentration, sample volume, sample flow rate, washing solvent, elution solvent, and type of sorbent were evaluated. After sample preparation of muconic acid as urinary metabolite of benzene, it was determined by HPLC-UV. In chromatographic analysis, column was C18 (250 cm × 4.6 mm id, 0.5 µm), UV wave length was 259 nm, mobile phase was H2O/methanol/acetic acid (69:30:1 v/v/v) was run at flow rate of 1 ml/min. Through experimental evaluation, a strong anion exchange silica cartridge (SAX) has been found successful in simplifying sample preparation compare to C8 and C18. There were significant difference between recoverie of muconic acid when different washing solvent, sample volume, and sample flow rate were used (p< 0.001). An optimum recovery was obtained when sample pH was adjusted at seven. Other optimum conditions were: sample flow rate 1 ml/min washing solvent acetic acid 1% , and acetic acid 10% as elution solvent. In this study, there was no significant difference when different sample concentrations were used (p>0.05). Recovery of spiked urine sample at concentrations of 0.1, 1, 10 µg/ml were more than 95%. The limit of detection of the optimized method was 0.01 µg/ml, showing 20 times less than biological exposure index (BEI). The optimized method was then validated with three different pools of samples at above mentioned concentrations and showed a good reproducibility over six consecutive days as well as six within-days experiments.

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Background and Aim: The lack of balance between job needs and workers' physical capacity may lead to work-related musculoskeletal disorders (Wises). WMSDs are one of the most important occupational health problems in developing countries. These problems are due to risk factors such as poor work postures, excessive force applied, repetitive movements, vibration, prolonged work duration, and psychological factors, leading, ultimately, to disorders ranging from mild low back pain to severe disabilities. This study aimed at determining the prevalence of WMSDs in different body regions, assessing posturing, and detecting ergonomic and individual risk factors causing musculoskeletal disorders, in Araki bakery workers in Arak, Iran.

Methods and Materials: In this cross - sectional study 233 randomly selected bakery workers in Arak were included, and the prevalence of symptoms of musculoskeletal disorders and their risk factors, with particular emphasis on work posture, was determined in them. The method used was OWAS and the NMQ Questionnaire.

Results: The highest prevalences of musculoskeletal disorders were in the knees (62.2%), low back (58.8%), legs (53.9%) and shoulders (44.6%) of the workers. Low back and shoulder injuries in Shaaters (workers in charge of baking the bread) and elbow, thigh and low back disorders in Choongeers (workers in charge of dividing and rounding the dough) were more prevalent than in other occupations. There is a positive association between type of occupation and these disorders (p<0/05). According to the OWAS's classification, the distribution of bakery workers' working postures was as follows: 58.5% in the action category 1 (natural posture), 34.7% in the action category 2 (stress posture), 4% in the action category 3 (harmful posture), and 2.5% in the action category 4 (very harmful posture). There was a significant relation between work service record and neck, elbow, shoulder, and knee disorders (p<0/05).

Conclusion: This study revealed that the working postures of 42.2% of Aaraki bakery workers were slightly to very harmful postures in addition, there was a high prevalence of WMSDS in different body regions of the workers. Ergonomic interventions are essential to improve the situation and protect better the health of the workers.