[Study on the occupational exposure limit of glyphosate in the air of workplace]

Objective: To establish occupational exposure limits for glyphosate in workplace air. Methods: In November 2014, by searching the documents of the United States Environmental Protection Agency (EPA) on glyphosate toxicity, the toxicity data and clinical symptoms of glyphosate toxicity were collected through various literature databases, and the target organs of glyphosate toxicity were determined. A total of 5 representative production enterprises in Jiangsu Province and Shandong Province were selected for field investigation. A total of 968 people were selected as the study subjects, including 526 workers exposed to glyphosate as the contact group, and 442 off-site (such as financial, administrative, etc.) workers with enterprises as the control group. Health examination was carried out in the exposure group and the control group to observe the damage of target organs of workers with different exposure concentrations and determine the occupational exposure limit. Results: The main target organs of glyphosate are liver and kidney and its effect on cholinesterase activity. The time-weighted average concentration (TWA) of glyphosate exposure in the exposure group was <0.03~48.91 mg/m(3), and there were statistically significant differences in liver and renal function between the exposure group and the control group (P<0.05). When the concentration of glyphosate in the air was higher than 5 mg/m3, there was a statistically significant difference in the abnormal rate of renal function between the exposure group and the control group (P<0.05) . Conclusion: The study sets the occupational exposure limit of glyphosate as 5 mg/m(3). The safety of this standard conforms to the relevant requirements of toxicology and occupational disease epidemiology, and also conforms to the existing economic and technological level in my country, and is highly feasible.

[A panel study on the effect of atmospheric PM2.5 exposure on the gut microbiome in healthy elderly people aged 60-69 years old]

Objective: To analyze the short-term effect of individual atmospheric PM_2.5 exposure on the diversity, enterotype, and community structure of gut microbiome in healthy elderly people in Jinan, Shandong province. Methods: The present panel study recruited 76 healthy elderly people aged 60-69 years old in Dianliu Street, Lixia District, Jinan, Shandong Province, and followed them up five times from September 2018 to January 2019. The relevant information was collected by questionnaire, physical examination, precise monitoring of individual PM_2.5 exposure, fecal sample collection and gut microbiome 16S rDNA sequencing. The Dirichlet multinomial mixtures (DMM) model was used to analyze the enterotype. Linear mixed effect model and generalized linear mixed effect model were used to analyze the effect of PM_2.5 exposure on gut microbiome α diversity indices (Shannon, Simpson, Chao1, and ACE indices), enterotype and abundance of core species. Results: Each of the 76 subjects participated in at least two follow-up visits, resulting in a total of 352 person-visits. The age of 76 subjects was (65.0±2.8) years old with BMI (25.0±2.4) kg/m². There were 38 males accounting for 50% of the subjects. People with an educational level of primary school or below accounted for 10.5% of the 76 subjects, and those with secondary school and junior college or above accounting for 71.1% and 18.4%. The individual PM2.5 exposure concentration of 76 subjects during the study period was (58.7±53.7) μg/m³. DMM model showed that the subjects could be divided into four enterotypes, which were mainly driven by Bacteroides, Faecalibacterium, Lachnospiraceae, Prevotellaceae, and Ruminococcaceae. Linear mixed effects model showed that different lag periods of PM_2.5 exposure were significantly associated with a lower gut α diversity index (P<0.05 after correction). Further analysis showed that PM_2.5 exposure was significantly associated with changes in the abundances of Firmicutes (Megamonas, Blautia, Streptococcus, etc.) and Bacteroidetes (Alistipes) (P<0.05 after correction). Conclusion: Short-term PM_2.5 exposure is significantly associated with a decrease in gut microbiome diversity and changes in the abundance of several species of Firmicutes and Bacteroidetes in the elderly. It is necessary to further explore the underlying mechanisms between PM_2.5 exposure and the gut microbiome, so as to provide a scientific basis for promoting the intestinal health of the elderly.

[Meta analysis of hearing loss caused by the combined effect of noise and heat in the working population]

Objective: To explore the effect of the combined effect of noise and heat on occupational hearing loss of workers by using Meta-analysis method. Methods: In August 2020, the Chinese and English literature on the relationship between exposure to noise and heat and occupational hearing loss published from January 2005 to August 2020 by CNKI, China Biomedical Literature Service System, Wanfang Data Knowledge Service Platform, VIP Official Database, Medline and PubMed Databases were searched, using noise, heat or hyperthermia, hearing as keywords. The selected data were analyzed by Stata 12.0 software, and the combined OR (95% CI) value included in the literature was calculated. Sensitivity analysis was used to explore the source of heterogeneity and analyze publication bias. Results: A total of 14 literatures (14 in Chinese, 0 in English) were included in the analysis, and 38654 subjects were included, including 6411 workers in the noise and heat combined effect group and 32243 workers in the noise alone group. The probability of hearing loss in the noise and heat combined effect group was 1.39 times higher than that in the noise alone group (95%CI: 1.14-1.69). The effect size OR was stable after sensitivity analysis, and there was no publication bias in the included literatures tested by Egger's and Begg's Method (z=0.38, P=0.702, t=-0.74, P=0.476) . Conclusion: Simultaneous exposure to noise and heat may increase the risk of hearing loss for workers in noisy workplaces.

[Analysis of electrocardiogram and blood related indicators in workers occupationally exposed to mercury in Jiangsu Province from 2016 to 2018]

Objective: To investigate the health status of occupational mercury workers and reveal the effects of mercury exposure on the cardiovascular system. Methods: In June 2019, a total of 2651 mercury workers participated in the occupational health examination between 2016-2018 from a thermometer manufacturing plant and a fluorescent lamp manufacturing plant were included in this study. Then, they were divided into a high-level mercury exposure group (425 workers whose urine mercury concentration >35 μg/g creatinine) and a low-mercury mercury exposure group (2226 workers whose urinary mercury concentration <35 μg/g creatinine) . Mercury concentration in the workplace was also detected. Finally, the results of electrocardiogram (ECG) , blood routine, blood biochemistry and other physical examinations were analyzed. The measurement data of age and exposure years were analyzed by test. Urinary mercury and blood parameters were analyzed by Mann-Whitney nonparametric test. Chi-square test was used for the analyses of gender, ECG abnormality rate and other categorical data. Results: The 8-hour weighted average allowable concentration (CTWA) of mercury in the workplace of high-exposure group was 0.002 2-0.152 mg/m(3). The abnormal rate of ECG in the high-exposed group (29.6%) was higher than that in the low-exposure group (10.1%) in 2018 (P<0.01) . Compared with the low-exposure group, the WBC of the high-exposure group from 2016 to 2018 was increased, with statistically significance (P<0.05) ; the RBC of the high-exposure group in 2016 and 2017 was decreased, with statistically significance (P<0.01) ; the total bilirubin concentration in the high-exposure group was decreased from 2016 to 2018, with statistically significance (P<0.05) . Conclusion: Long-term exposure to high concentration of mercury in the workplace may influence cardiovascular system. Therefore, engineering protection and individual protection should be implemented well.

[Value of plasma microRNAs has-let-7d and has-let-7e as potential molecular markers in workers with occupational exposure to mercury]

Objective: To investigate whether plasma microRNAs has-let-7d and has-let-7e can be used as potential molecular markers for workers with occupational exposure to mercury. Methods: October 2013, the workers with occupational exposure to mercury who worked in a mercury thermometer factory and participated in occupational health examination were selected as subjects, and biological samples and basic data were collected. The subjects were divided into chronic mercury poisoning group,mercury absorption group,and control group,with 30 individuals in each group. AmicroRNA microarray combined with RT-qPCR was used to measure the expression of has-let-7d and has-let-7e in the three groups, the receiver operating characteristic(ROC)curve was used to analyze the values of has-let-7d and has-let-7e in the diagnosis of occupational chronic mercury poisoning,a software platform was used to predict target genes. Gene ontology enrichment analysis and KEGG pathway analysis were also performed. Results: Compared with the control group, the chronic mercury poisoning group and the mercury absorption group had significant increases in the expression of has-let-7d and has-let-7e(P<0.05). The areas under the ROC curve for microRNAs has-let-7d and has-let-7e in the diagnosis of occupational chronic mercury poisoning were 0.912(95% confidence interval[CI]0.843-0.981)and 0.908(95%CI0.837-0.979),respectively,and there was a significant difference between them(P<0.001). Conclusion: Plasma microRNAs has-let-7d and has-let-7e can be used as potential molecular markers for workers with occupational exposure to mercury.

[Study of the effect of occupational exposure to glyphosate on hepatorenal function]

Objective: To explore the effect of occupational exposure to glyphosate on hepatorenal function. Methods: 526 workers who were occupationally exposed to glyphosate from 5 glyphosate-producing factories were selected as cases; and another 442 administrative staffs who were not exposed to glyphosate were selected as controls from April to November, 2014. All the subjects accepted occupational health examination. The concentration level of glyphosate in the air of workshop was detected and the time weighted average concentration (TWA) was calculated. And analyze the difference of hepatorenal fuction between case group and control group. Result: The age of the subjects in the case and control groups were separately (35.6±10.3), (34.3±9.7) years old, with the length of working for (6.5±5.7), (7.7±6.8) years. The TWA of glyphosate in the case group was between <0.03-48.91 mg/m(3), with the geometric mean at 3.78 mg/m(3). The overall rates of abnormal hepatic and renal function in the case group were 14.4% (76 cases) and 16.2% (85 cases), respectively; while those were 5.0% (22 cases) and 4.8% (21 cases), respectively in control group, and the difference showed statistical significance (P<0.05). When TWA reached <0.03-6.00 mg/m(3), the difference of hepatorenal fuction between case group and control group showed statistical significance, and the rates of abnormal hepatic and renal function was 8.0% (36/447) and 9.8% (44/447) respectively in case group. When cumulative exposure level reached <1.56-68.64 g, the difference of hepatorenal fuction between case group and control group showed statistical significance, and the rates increased to 9.2% (37/404) and 10.4% (42/404) respectively in group of cases. Conclusion: Glyphosate can affect the hepatic and renal function among occupational exposure population, and there was an association between the effect and the exposure dose.