Iran Occupational Health

Abstract
Background and aims: Decades after the introduction of nanotechnology as a new field of research and production, the pace of development of this field has been remarkable. These advances have enabled nanomaterials to be used in various sectors and industries including electronics, optics, consumer goods, energy production and storage, soil and water conservation, as well as in medicine for therapeutic and diagnostic purposes. Worldwide sales of nanomaterials were $ 22.9 billion in 2013 and with annual growth of 19.8%, it is expected to reach US $ 64.2 billion by the end of 2019; Therefore, many economists consider the production and use of nanomaterials an integral part of future economic activities. These advances are due to the unique physico-chemical and biological properties of nanoscale materials. The large surface-to-volume ratio, size and surface characteristics of nanomaterials are the most important physico-chemical properties of them. The specific physico-chemical properties of nanomaterials have led them to show specific behaviors in interaction with biological systems; The most important of these behaviors are moving towards secondary target organs, poor clearance by macrophages, the ability to transmit through the axons of sensory neurons, and to reach intracellular structures such as mitochondria and the nucleus. These properties, in addition to their many applications, have also raised concerns about the potential effects of these substances on human health and the environment. These concerns have generated a large wave of research in the fields of nanomaterials safety, health and toxicology. Forecasts show that the number of staff exposed to nanomaterials will reach about 6 million by the end of 2020. Concerns are increasing day by day as the number of workers exposed to nanomaterials increases. In our country more than 200 companies are active in the field of production and using nanomaterials. These companies have received 517 nanoscale certification for their products, until January 2019. Their products are exported to 49 countries and 5 continents worldwide. The increasing growth of these activities in the country necessitates attention to the safety, health and environmental aspects of nanotechnology. According to what was said, this study aimed to investigate the relationship between the symptoms of employees of nanomaterials producing and consuming companies with chemical composition (as a factor affecting the type and severity of effects) and physical state (as an influencing factor on exposure) of the nanomaterials.
Methods: The present study is a descriptive cross-sectional study carried out in 2018 among employees of nanotechnology companies in Tehran. Specifications of the companies were provided by correspondence with the Ministry of Industry, Mine & Trade. Of the companies invited, 52 companies agreed to participate in the study. Staff symptoms were assessed using a nonspecific symptoms questionnaire. The questionnaire was designed and validated in a period of two months by a team of 19 experts in the fields of occupational health, occupational medicine, toxicology, medical nanotechnology and health education. The required information about the occupational characteristics, chemical composition and physical state of the nanomaterials used in the companies was also collected using the NanoTool method form. The questionnaire and the form were then emailed to staff exposed to nanomaterials. Staff inclusion criteria were "to have direct exposure to nanomaterials, that is, to produce or consume nanomaterials during their daily working processes" and "to have at least one year of experience". Of the 52 companies that agreed to participate in the study, 198 completed questionnaires and completed forms were received. Finally, data were analyzed using SPSS.22 software. Frequency distribution tables and Chi-squared test, Fisher exact test and Kruskal-Wallis test were used for this purpose.
Results: The study of the characteristics of the subjects showed that their mean age was 33.76 (SD = 6.108) years; Their average work experience was 6.76 (SD = 5.217) years. Study participants were well educated, with 61.2% having a master's or doctorate degree. 49% (96) of the subjects were men and 51% (100) of them were women. Manufactured / consumed nanomaterials in companies were investigated in similar groups in terms of chemical composition (metal, metal oxide, carbonous and the others) and physical state (dry powder, suspension/ emulsion, paste/gel and the others). The results of investigating the frequency of symptoms of nanotechnology companies’ employees using nonspecific symptoms questionnaire showed that the frequency of some skin symptoms such as "redness", "itching" and "roughness" were 72.7%, 67.2% and 62.6%, respectively. the frequency of some respiratory symptoms were also high; "cough" (64.1%), "sneezing" (60.6%) and "sore throat" (60.1%). High-frequency ocular symptoms included "eye irritation" (66.2%), "itchy eyes" (28.3%), and "red eyes" (25.3%).
Investigation of the correlation between the skin symptoms of the employees with the chemical composition and physical state of the nanomaterials used in the companies showed that the symptoms "skin roughness", "skin itching", "skin rash" and "hair loss" have significant correlation with the physical state of nanomaterials and "skin redness", " Skin darkness "and" skin rash" have significant relationship with the chemical composition of nanomaterials. Investigation of the relationship between employees' gastrointestinal symptoms with the chemical composition and physical state of the nanomaterials used in the companies showed that the symptoms "appetite suppression", "thirst", "nausea/vomiting" and "darkness of stool color" have significant relationship with the physical state of nanomaterials and "thirst", "Nausea/vomiting" and "inability to detect taste" have significant relationship with the chemical composition of nanomaterials. Evaluation of the relationship between neurological symptoms of staff with the physical state and chemical composition of nanomaterials showed the significant relationship between "movement problems" and chemical composition of nanomaterials. Also, "dizziness" and "sleeplessness/wakefulness" were significantly associated with both the chemical composition and the physical state of the nanomaterials. Investigating the relationship between the chemical composition and physical state of the nanomaterials with the respiratory symptoms of staff revealed "shortness of breath", "wheezing", "chest heaviness", "difficult breathing", "increased phlegm" and "voice change" significantly correlated with Both the chemical composition and the physical state of the nanomaterials. "Cough" was also significantly associated with the chemical composition of the nanomaterials. Examination of the correlation between ophthalmic symptoms and chemical composition and physical state of nanomaterials indicated that the symptoms "blurred vision" and "visual impairment" were significantly correlated with the chemical composition of the nanomaterials. Also, "increased eye gum" and "red eyes" were significantly associated with both the chemical composition and the physical state of the nanomaterials.
Conclusion: Given the frequency of symptoms in staff exposed to nanomaterials, their statistical association with the chemical composition and physical state of nanomaterials, Staff's attitude toward nanomaterials that are generally considered safe, inadequate and generally inappropriate use of personal protective equipment appropriate to work with nanomaterials and lack of education and training about the effects of nanomaterials on health and the environment, existing these problems among the employees of these companies are reasonable and that is an important issue. Therefore, the following are suggested to reduce occupational exposure to nanomaterials: Provide adequate training to the staff of these companies in the areas of basic concepts of nanosafety, standard work procedures when working with nanomaterials, appropriate personal protective equipment for working with nanomaterials and using them properly and waste management of nanomaterials.