Journal of Health and Safety at Work

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Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer.

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Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA), and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated.

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Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C) and the lowest value was for plowing (29.98 °C). ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers.

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Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced in different tasks due to heat and this reduction is exacerbated by increase in temperature and might impact the local economy. Thus, further studies are needed to improve the working conditions.

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Introduction: The most common of farmers' occupational exposure is exposure to pesticides. Organophosphate pesticides (OP) are widely used in agriculture to control pests. The main mechanism of Organophosphates (OPs) toxicity is irreversibly inhibiting of Butyl cholinesterase and acetyl cholinesterase. POEM model (Predictive Operator Exposure Model) was made to assess exposure and absorption of the pesticides. The aim of this study was to estimate the rate of exposure of farmers in West of Iran to organophosphates with POEM model and to compare its results with activity level of plasma cholinesterase (PChE).
Methods and Materials: In this descriptive and analytical research, farmers were divided into two same groups who were exposed to diazinon. One group of them wore full personal protective equipment (PPEs) and the second group including farmers with daily routine work had no proposed personal protective equipment. Before and after spraying operation, a blood sample was collected from both groups of farmers, as well as from control group. Then plasma cholinesterase activity was measured by DGKC (German Biochemical Society) and photometric device. Farmer’s exposure to OPs was estimated with POEM model.
Results: The activity mean PChE enzyme in the groups with and without personal protective equipment was 11639.3 mg/l and 8516.3 mg/l, respectively. The mean of predicted total absorbed dose and predicted total exposure to toxic substance in group with PPEs was 9.1 mg/day and 0.15 mg/kgbw/day, respectively and in group with PPEs were 0.5 mg/day and 0.009 mg/kgbw/day, respectively. dermal exposure average, percentage of dermal absorption, absorbed dose at the time of preparing the poison solution and spraying, by using of the POEM model was significantly higher in the no PPE group than in the PPE group (P<0.001).
Conclusion: This study showed that the use of personal protective equipment prevents from the effects appearing of pesticides by reducing the activity of PChE. With the increasing in PChE activity, the values of POEM model parameters decreases such as the absorbed dose of the skin and the inhalation of the toxin. Therefore, the POEM model can be used to check the exposure of people with pesticides. Finally, this study suggests that from the POEM model can be considered as a screening tool to identify individuals at exposure of pesticides to the next steps for biological monitoring, diagnosis and treatment and … .