Mahmoud Heidari

Dispersive liquid−liquid microextraction solidified floating organic drop (SFOD−DLLME) technique was used for sample treatment and extraction of hexavalent chromium from spiked and real samples of workplace ambient air and urine of chromium electroplating workers. Validation of the SFOD−DLLME technique with three solvents, namely, 1-undecanol, 2-dodecanol and n-hexadecane, showed that pH 4, stirring rates of 600 rpm for 1-undecanol and 2-dodecanol and 800 rpm for n-hexadecane, extraction times of 10 min for 1-undecanol and 2-dodecanol and 15 min for n-hexadecane were the conditions allowing to reach the highest extraction efficiency. The maximum acquired enrichment factor was 211 and LODs were in the range of 0.015–0.05 µg/L, and the calibration curves were linear in the range of 0.5–30 µg/L. The results showed that SFOD−DLLME coupled with atomic absorption spectroscopy is a precise and sensitive technique for the determination of hexavalent chromium for biological monitoring of occupational/environmental samples.

Forest workers encounter many health-related problems due to their harsh working conditions. This study focused on the evaluation of the physical workload of tree fellers during clearcut operations in a pine plantation forest in northern Iran by means of heart rate measurements. Anthropometric and personal data of the subjects such as age, body mass index (BMI), work experience, and health problems were also collected. The subjects were also asked to assess their perceived level of fatigue by means of the Swedish Occupational Fatigue Inventory. Activity sampling was used to record the physical workload of 13 subjects during a working day of 8 h for each one of them by means of a Polar Electro H10 heart rate sensor. The collected data were used for the calculation of heart rate indices that determine the strain of the subjects. The results showed that the mean level of physical workload was 43.54% of the relative heart rate (HRR) which corresponds to heavy work. The workers assigned most of the effective work time to tree processing (39.78%), back cut (18.6%), and undercut (12.07%). The highest mean heart rates (HR_work) were measured during the work elements of tree processing (117.7 bpm), back cut (115.6 bpm), and undercut (114.8 bpm). The study results also showed that the number of harvested trees and the average tree diameter at breast height exerted a significant impact on HRR and the BMI class on HR_work. Furthermore, age class was negatively correlated to net productivity.

Background and Objective: Exposure to formaldehyde has adverse effects on health both acutely and over the long term (e.g., carcinogenicity). The substance is widely used in pathology and histology departments. This study focused on cancer risk of formaldehyde in pathology department of five hospitals in Rasht. Materials and Methods: Sampling and determination of formaldehyde in pathology department were carried out based on the NIOSH method of 3500. The working condition and working environment were investigated and a semi quantitative risk assessment were used to health risk assessment of formaldehyde and The individual lifetime cancer probability, which is defined as the increase in the probability of developing cancer during continuous exposure to an air pollutant were used to assess health risks with formaldehyde. Results: The results showed that the exposure level of all subjects were higher than the Occupational Exposure Limit for 8 hours exposure time of formaldehyde. However, in the five occupational groups, the highest weekly exposure index was observed for the Lab Technicians (0.664 ppm) at Hospital no. 5, which could have been due to more daily working hours at this sampling site and a lack of adequate ventilation. The formaldehyde concentration was in the 0.0192 to 0.326 ppm ranges for five hospital pathology departments. The cancer risk ranged from 9.52×10-5 to 1.53×10-3, and it was greater than the WHO acceptable cancer risk level.Conclusions: The results of the risk assessments can be used for managing the chemical exposure of allocated resources for defining control actions. This process plays an important role in reducing the level of exposure to formaldehyde in pathology departments.

In this study, the application of a novel nanomaterial composite was investigated in two microextraction techniques of solid‐phase microextraction and a needle trap device in a variety of sampling conditions. The optimum sampling temperature and relative humidity were 10°C and 20%, respectively, for both techniques with two sorbents of graphene/silica composite and polydimethyl siloxane. The two microextraction techniques with the proposed sorbent showed recoveries of 95.2 and 94.6% after 7 days. For the needle trap device the optimums desorption time and temperature were 3 min at 290°C and for SPME these measures were 1 and 1.5 min at 240–250°C for the graphene/silica composite and polydimethyl siloxane, respectively. The relative standard division obtained in inter‐ and intra‐day comparative studies were 3.3–14.3 and 5.1–25.4, respectively. For four sample the limit of detection was 0.021–0.25 ng/mL, and the limit of quantitation was 0.08–0.75 ng/mL. The results show that the graphene/silica composite is an appropriate extraction media for both techniques. Combining an appropriate sorbent with microextraction techniques, and using these in conjunction with a sensitive analytical instrument can introduce a strong method for sampling and analysis of occupational and environmental pollutants in air.

Single-walled carbon nanotubes (SWCNTs)/silica composite coating for solid phase microextraction synthesized by sol-gel technology was developed for air sampling and determination of perchloroethylene