Reply to: A commentary on “Hair analysis for biomonitoring of environmental and occupational exposure to organic pollutants.”

In his comment on the review by Appenzeller and Tsatsakis, Doréa highlights the use of hair analysis for the biomonitoring of human exposure to mercury. Indeed, the relevance of this matrix for this specific purpose has been demonstrated in numerous works. We acknowledge that the review was voluntarily limited to “purely organic” pollutants, which excluded organic forms of metals such as methylmercury and ethylmercury. We also remind some important aspects related to the use of hair as a biomarker of exposure to mercury.     

Effects of long-term occupational solvent exposure on contrast sensitivity and performance in visual search

Sensitive and easily applicable screening tests are greatly needed for the early detection of nervous system dysfunction in people working with neurotoxic substances. Previous studies have shown that long-term solvent exposure may cause deficits in visual perception. We, therefore, studied the effects of long-term occupational solvent exposure and chronic encephalopathy on performance in three vision tests novel in the present context. Two visual search tasks were used: the letter search test measured the speed of finding a letter in an array of numerals, and the pop-out search test required the observer to detect the presence or absence of a tilted line segment in an array of vertical line segments. With the letter contrast sensitivity test we measured the contrast threshold for the identification of band-pass filtered letters. Before testing, comprehensive eye examination was carried out to reveal any structural or functional abnormality and to ensure correct refraction. The patients had healthy eyes, 2 out of 14 had reduced contrast sensitivity (Vistech) and 5 out of 14 had deficits in colour vision (FM 100). In both visual search tasks, the patients were statistically highly significantly (p < 0.001) slower than the age-matched control observers. Instead, in the contrast sensitivity test, the difference between the patient and the control group was small relative to normal variability although still statistically significant (p < 0.05). The results suggest that visual search tests can be useful in evaluating and characterising the effects of long-term solvent exposure on visual perception. Because our patients’ letter contrast sensitivity was only moderately deteriorated, it seems that the observed defect of visual search cannot be explained by deteriorated letter identification alone, although it can be a contributory factor. Rather, the finding suggests that the speed by which visual information is transmitted and/or processed in the central visual system has become considerably slower.     

Colour vision and contrast sensitivity losses of mercury intoxicated industry workers in Brazil

We evaluated vision loss in workers from fluorescent lamp industries (n = 39) who had retired due to intoxication with mercury vapour and had been away from the work situation for several years (mean = 6.32 years). An age-matched control group was submitted to the same tests for comparison. The luminance contrast sensitivity (CSF) was measured psychophysically and with the sweep visual evoked potential (sVEP) method. Chromatic red–green and blue–yellow CSFs were measured psychophysically. Colour discrimination was assessed with the Farnsworth–Munsell 100-hue test, Lanthony D-15d test and Cambridge Colour Vision Test. Patient data showed significantly lower scores in all colour tests compared to controls (p < .001). The behavioural luminance CSF of the patients was lower than that of controls (p < .001 at all frequencies tested). This result was confirmed by the electrophysiologically measured sweep VEP luminance CSF except at the highest frequencies—a difference that might be related to stimulus differences in the two situations. Chromatic CSFs were also statistically significantly lower for the patients than for the controls, for both chromatic equiluminant stimuli: red–green (p < .005) and blue–yellow (p < .04 for all frequencies, except 2 cycles per degree (cpd), the highest spatial frequency tested) spatial gratings. We conclude that exposure to elemental mercury vapour is associated with profound and lasting losses in achromatic and chromatic visual functions, affecting the magno-, parvo- and koniocellular visual pathways.     

枣庄血站2002~2012年职业暴露监测分析

目的：了解采血人员、检验人员和成分分离人员的职业暴露情况。方法统计不同科室2002~2012年的职业暴露情况。结果2007~2012年采血人员、检验人员和成分分离人员的职业暴露人数分别为173、87、92人次。2007~2012职业暴露情况高于2002~2006年, P〈0.05;暴露类型比较, P〈0.001;暴露级别比较, P〈0.001。结论随着采血量的增加和工作量的加大,职业暴露有增加的可能。     

临床护士职业暴露与标准预防的管理探讨

目的了解临床护士的职业暴露现状,职业暴露的危害性因素对护士的影响,探讨职业安全管理的有效方法。方法对全院151名临床护士采用调查问卷随机抽样法,对2007年和2008年发生的职业暴露事件进行回顾性分析。结果加强标准预防教育后,护理人员的职业安全意识明显提高,发生职业暴露事件明显减少。结论临床护士职业暴露发生率高,应强化护理人员的职业安全意识,加强医护人员的职业防护培训,以促进职业安全,使职业暴露的发生率降至最低。     

Influence of occupational styrene exposure on memory and attention

Short-term memory, perceptual speed, attention and psychomotor function were studied in 55 workers professionally exposed to styrene. The subjects were grouped according to their urinary styrene metabolites. Those with higher styrene exposure showed a significant impairment of short-term memory only.     

医护人员眼部职业暴露原因分析

目的 探讨医护人员眼部职业暴露的原因,拟制定防护措施.方法 收集本院2004年1月至2011年12月上报院感管理科职业暴露人员资料,进行回顾性分析.结果 有30例发生眼部职业伤害,30例医护人员中,以手术科的人员为主共28例,专业技术职称以初级职称为主26例,构成比为86.7％,人员类别以护理人员为主19例,构成比为63.3％,造成眼部职业暴露的物质以血液为主12例,构成比40％,伤害的环节以剖宫产手术为主11例,构成比36.7％.结论 预防眼部职业暴露的措施是：重点加强年轻的术科医护人员职业暴露知识教育,提高操作技术及防护意识,医院提供适合的护眼用品,减少医护人员职业暴露的发生率.     

Influence of chronic exposure to organic solvent mixtures on contrast sensitivity in silk-screen printers: matched-pair analysis

The aim of the study was the determination of the influence of chronic occupational exposure to organic solvent mixtures on the contrast sensitivity (CS) of silk-screen printers. Contrast sensitivity was measured for 28 matched (age, sex) pairs of silk-screen printers and controls using the Vision Contrast Test System – VCTS 6500 chart. The duration of exposure to industrial neurotoxic substances was about 9 years. Contrast sensitivity impairments were recorded in 28.6% of the printers for both eyes at several spatial frequencies. Males and females differed in CS significantly, but no interaction between gender (male vs. female) and exposure (printers vs. controls) was found.     

Extensive changes to occupational exposure limits in Korea

Occupational exposure limits (OELs) are used as an important tool to protect workers from adverse chemical exposures and its detrimental effects on their health. The Ministry of Labor (MOL) can establish and publish OELs based on the Industrial Safety and Health Act in Korea. The first set of OELs was announced by the MOL in 1986. At that time, it was identical to the Threshold Limit Values of the American Conference of Governmental Industrial Hygienists. Until 2006, none the first OELs except for those of three chemicals (asbestos, benzene, and 2-bromopropane) were updated during the last twenty years. The Hazardous Agents Review Committee established under the MOL selected 126 chemicals from 698 chemicals covered by OELs using several criteria. From 2005 to 2006, the MOL provided research funds for academic institutions and toxicological laboratories to gather the evidence documenting the need to revise the outdated OELs. Finally, the MOL notified the revised OELs for 126 chemicals from 2007 to 2008. The revised OELs of 58 substances from among these chemicals were lowered to equal or less than half the value of the original OELs. This is the most substantial change in the history of OEL revisions in Korea.     

Distribution of mercury in guinea pig offspring after in utero exposure to mercury vapor during late gestation

Organ distribution of mercury after in utero mercury vapor exposure was investigated in neonatal guinea pigs. Mother guinea pigs in late gestation were exposed to 0.2–0.3 mg/m³ mercury vapor 2 h per day until giving birth.Mercury concentrations in neonatal brain, lungs, heart, kidneys, plasma and erythrocytes were much lower than those of maternal organs and tissues. Neonatal liver, however, showed a mercury concentration twice as high as maternal liver. Mercury concentration ratios of erythrocytes to plasma in offspring were quite different from those of mothers, being 0.2–0.4 for offspring, and 1.3–3.0 for mothers.These results suggested that mercury vapor metabolism in fetuses was quite different from that in their mothers. This may be due to the different blood circulation, as mercury vapor transferred through the placental barrier would be rapidly oxidized into ionic mercury in fetal liver and accumulated in the organ.The different mercury vapor metabolism may prevent fetal brain, which is rapidly developing, and thus vulnerable, from being exposed to excessive mercury vapor.     

Cross-sectional study based on occupational aluminium exposure population

To evaluate the different characteristics of cognitive impairment caused by occupational aluminium exposure at different ages, we surveyed 1660 workers in Shanxi Aluminium Plant, China, and assessed their cognitive function and plasma aluminium concentration. In multiple linear regression, the scores of the digit-span test (DST) and digit-span backward test (DSBT) were negatively correlated with plasma aluminium concentration when concentration reached 34.52 μg/L in younger group (＜40 years), while in the middle-aged group (≥40 years) only found when concentration reached 42.25 μg/L (β<0, P < 0.05). In logistic regression, when plasma aluminum concentration reached 42.25μg/L, odds ratios (95 % confidence interval) were 1.695 (1.062–2.705) and 3.270 (1.615–6.620) for DST, 7.644 (3.846–15.192) and 15.308 (4.180–56.059) for DSBT in middle-aged group and younger group, respectively. These results showed that aluminium exposures were associated with cognitive impairment among aluminium-exposed workers, particularly for young workers who were more susceptible.     

助产士职业暴露防护教育依从性的现状及分析

目的：探讨助产士的职业安全及职业暴露的防护、教育、依从性的现状及防范措施。方法：对近10年来在我院从事过助产工作的助产士,进行回顾性问卷调查。了解她们在助产工作中所发生的职业暴露的种类、方式和自身的防护意识,并对调查结果进行分析。结果：助产士最常发生的职业暴露是在产程监测、接生过程中被羊水、血液、阴道分泌物污染;其次是在给产妇进行会阴缝合、抽脐带血、注射催产素、进行会阴神经干阻滞麻醉等操作时易发生针刺伤。但助产士自身防护的依从性较差,一些防护措施、上报体系也不够健全,一旦发生职业暴露后的相应处理也有欠缺。结论：强化助产士对血源性疾病防护知识的教育,提高助产士在工作中自身防护的依从性;不断完善职业暴露上报体系;对已发生职业暴露的助产士给予有力的帮助,进行相应的处理,能有效地避免或减少助产士被血源性疾病感染。     

2014～2015年南充市禽流感职业暴露人群及环境监测结果分析

目的 了解南充市禽流感职业暴露人群H5N1感染及环境禽流感病毒污染状况.方法 2014～2015年采集南充市禽类职业暴露人群血清标本,用红细胞凝集抑制试验(HI)检测H5N1抗体;对城乡活禽市场、家禽规模养殖、野鸟禽鸟栖息地以及禽类宰杀市场等场所的笼子、粪便以及污水标本采用实时荧光定量PCR法检测禽流感病毒(甲型流感病毒,即FluA)核酸.结果 共采集职业暴露人群160份血清标本,H5N1抗体结果均为阴性采集环境标本160份进行禽流感病毒核酸检测,FluA核酸阳性31份,总检出率为16.32％.其中H5、H7、H9核酸阳性分别是18份、0份、10份,H5、H7、H9检出率分别是9.47％、0％、5.26％,FluA核酸阳性未分型3份,未分型检出率为1.58％,不同类型标本、不同监测点环境、不同监测场所及不同季节监测结果比较差异有统计学意义(x2值分别是37.43、8.67、30.57和30.44,P＜0.05).结论 禽流感H5亚型在南充市职业暴露人群中未发现隐性感染,南充市各类型标本、各监测场所、各监测点环境及各季节均存在禽流感病毒,建议各相关政府部门加强对禽流感相关知识的宣传,加强交易以及宰杀市场等的监管,加强对外环境的监测,必要时采取短期关闭活禽交易、禽类宰杀市场,季节性休市等措施,降低禽流感病毒感染的风险.     

产妇经血传播疾病检测对助产士职业暴露预防的意义

目的探讨产妇产前经血传播疾病检测对助产士职业暴露在医院感染控制中的意义。方法对2007年10月至2009年10月间的产妇进行乙型肝炎表面抗原（HBsAg）、丙型肝炎抗体（抗HCV）、艾滋病抗体（抗HIV）、甲苯胺红不加热血清试验（TRUST）检测,并对助产士在这两年间所发生的职业暴露进行统计分析。结果检出HBsAg阳性521例,阳性牢16．35％抗-HCV阳性4例,阳性率0．13％;抗-HIV阳性1例,阳性率0．03％;TRUST阳性12例,阳性率0．38％;助产士发生职业暴露5例,暴露率7．9％;经过随防一年,未发生医院院内感染。结论产前检测经血传播性疾病可事先知晓产妇经血传播疾病的感染情况,使助产士更严格遵循安全的操作流程,规范操作,自觉加强防护,对助产士职业暴露防治、对医院感染控制、对提高职业防护的依从性和执行率有着重要意义,大大降低助产士职业暴露的风险。     

某纺织厂噪声作业工人听力损失与工龄、累积噪声暴露量关系的调查

目的调查某纺织厂噪声作业工人的听力损失与稳态噪声暴露、工龄和累积噪声暴露量的关系。方法采用横断面研究方法,于2010年2月～2011年1月对某纺织厂60名暴露职业噪声超过1年的工人进行调查,测量他们工作环境的噪声水平,调查他们的年龄、性别、工作年限、平均每天噪声工作时间、每周工作天数,并计算累积噪声暴露时间,同时测量他们的听力水平。结果对工作环境测定的14个点的噪声强度均超过国家标准。60名作业工人听力损失的检出率为28.33%,听力损失检出率随工龄的增加呈显著上升趋势（P=0.043）,听力损失的检出率（P=0.021）以及损伤程度（P=0.013）均与累积噪声暴露量呈显著正关联。结论纺织厂工人长期暴露职业噪声可导致听力损失,提示应加强纺织厂工作环境噪声的控制,促进工人的听力健康。     

职业接触抗肿瘤药物对护士外周血淋巴细胞凋亡及Fas bcl-2基因表达的影响

目的探讨职业接触抗肿瘤药物对护士外周血淋巴细胞凋亡及Fas、bcl-2基因表达的影响。方法选择接触抗肿瘤药物5年以上,每日接触5人次以上的护士为接触组;无抗肿瘤药物接触史的健康志愿者为对照组。抽取接触组及正常对照组外周静脉血各2ml,乙二胺四乙酸(EDTA)抗凝,利用流式细胞仪技术观察外周血淋巴细胞凋亡率及Fas、bcl-2基因的表达。结果接触组外周血淋巴细胞凋亡率明显增高(P<0.05);接触组Fas基因的表达明显增高(P<0.01);而bcl-2基因表达差异无统计学意义。结论抗肿瘤药物能促进职业接触护士外周血淋巴细胞的凋亡和Fas基因的表达。     

Changes in correlation coefficients of exposure markers as a function of intensity of occupational exposure to toluene

This study was initiated to identify a marker of choice to monitor occupational exposure to toluene through quantitative evaluation of changes in correlation coefficients (CCs), taking advantage of a large database. Six known or proposed exposure markers in end-of-shift blood (B) and urine (U) were studied, i.e., toluene in blood (Tol-B) and benzyl alcohol, benzylmercapturic acid, o-cresol, hippuric acid and toluene in urine (BeOH-U, BMA-U, o-CR-U, HA-U, and Tol-U, respectively). To construct a database, data on 8-h time-weighted average intensity of occupational exposure to toluene and resulting levels of the six exposure markers in blood or urine were cited for 901 cases from previous four publications of this study group and combined with 146 new cases. In practice, 874 cases (all men) were available when extremely dilute or dense urine samples were excluded. The 874 cases were classified taking the upper limit (from 120 ppm to 1 ppm) of the toluene exposure concentration, and the CCs for the six markers with TWA toluene exposure intensity were calculated. For further evaluation, the 874 cases were divided into 10%-tiles in terms of TWA toluene exposures, and several 10%-tiles were combined so that sufficient numbers of cases were available for calculation of the CCs at various levels of toluene exposure. Perusal was made to know whether or not and which one of the six makers gave significant CC even at low level of toluene exposure. The CCs for BMA-U, o-CR-U and HA-U with TWA toluene exposure were well >0.7 when toluene exposure was intense (e.g., up to 60–100 ppm as the upper limit of the exposure range), but were reduced when the upper limit of toluene exposure was less than 50 ppm, and the CCs were as small as ≦0.2 when the upper limit was about 10 ppm or less. In contrast, Tol-U and Tol-B were correlated with exposure to toluene down to the ≦3 ppm range. The CC for BeOH-U was <0.1 almost throughout the exposure ranges. Further analyses showed that the CCs for all markers (except the CC for BeOH-U) were >0.4 when the cases in the 60th–100th%-tiles were examined. The CCs for Tol-U and Tol-B were >0.3 also for cases in the 0th–60th or 30th–70th%-tiles, whereas the CCs for other four markers were <0.3. In over-all evaluation, it was concluded that HA and o-CR are among the markers of choice to monitor occupational toluene exposure at high levels, and that only un-metabolized toluene in urine or in blood is recommended when toluene exposure level is low (e.g., 10 ppm or less). Toluene in urine may be preferred rather than that in blood due to practical reasons, such as non-invasiveness.     

Changes in correlation coefficients of exposure markers as a function of intensity of occupational exposure to toluene

This study was initiated to identify a marker of choice to monitor occupational exposure to toluene through quantitative evaluation of changes in correlation coefficients (CCs), taking advantage of a large database. Six known or proposed exposure markers in end-of-shift blood (B) and urine (U) were studied, i.e., toluene in blood (Tol-B) and benzyl alcohol, benzylmercapturic acid, o-cresol, hippuric acid and toluene in urine (BeOH-U, BMA-U, o-CR-U, HA-U, and Tol-U, respectively). To construct a database, data on 8-h time-weighted average intensity of occupational exposure to toluene and resulting levels of the six exposure markers in blood or urine were cited for 901 cases from previous four publications of this study group and combined with 146 new cases. In practice, 874 cases (all men) were available when extremely dilute or dense urine samples were excluded. The 874 cases were classified taking the upper limit (from 120 ppm to 1 ppm) of the toluene exposure concentration, and the CCs for the six markers with TWA toluene exposure intensity were calculated. For further evaluation, the 874 cases were divided into 10 per thousand in terms of TWA toluene exposures, and several 10 per thousand were combined so that sufficient numbers of cases were available for calculation of the CCs at various levels of toluene exposure. Perusal was made to know whether or not and which one of the six makers gave significant CC even at low level of toluene exposure. The CCs for BMA-U, o-CR-U and HA-U with TWA toluene exposure were well >0.7 when toluene exposure was intense (e.g., up to 60-100 ppm as the upper limit of the exposure range), but were reduced when the upper limit of toluene exposure was less than 50 ppm, and the CCs were as small as <==0.2 when the upper limit was about 10 ppm or less. In contrast, Tol-U and Tol-B were correlated with exposure to toluene down to the 0.4 when the cases in the 60th-100th per thousand were examined. The CCs for Tol-U and Tol-B were >0.3 also for cases in the 0th-60th or 30th-70th per thousand, whereas the CCs for other four markers were <0.3. In over-all evaluation, it was concluded that HA and o-CR are among the markers of choice to monitor occupational toluene exposure at high levels, and that only un-metabolized toluene in urine or in blood is recommended when toluene exposure level is low (e.g., 10 ppm or less). Toluene in urine may be preferred rather than that in blood due to practical reasons, such as non-invasiveness.     

Milk transfer and tissue uptake of mercury in suckling offspring after exposure of lactating maternal guinea pigs to inorganic or methylmercury

Maternal guinea pigs were injected with mercuric chloride (HgCl₂; 1 mg Hg/kg body weight) or methylmercury (MeHg; 1 mg Hg/kg) 12 h after parturition, and exposure of the offspring to mercury (Hg) via breast milk were studied on days 3, 5 and 10 postpartum. Milk Hg concentrations were lower than maternal plasma Hg concentrations regardless of the form of Hg given to the dams. Milk Hg was higher in HgCl₂-treated dams than in MeHg-treated dams. In MeHg-treated dams, MeHg was separately determined. While the ratio of MeHg to T-Hg decreased in the dams’ plasma, it did not in the milk. There was a strong correlation between milk and plasma T-Hg concentrations in HgCl₂ treated dams. In the milk of MeHg-treated dams, the plasma MeHg concentrations correlated better than did the plasma T-Hg concentrations. In the offspring, regardless of the chemical forms of Hg given to the dams, the highest Hg concentrations were found in the kidney, followed by the liver and the brain. Brain Hg concentrations were, however, significantly higher in the offspring of MeHg-treated dams than in those of HgCl₂-treated dams. In addition, Hg levels in the major organs of the offspring of HgCl₂-treated dams peaked on day 5 postpartum, while those of MeHg-treated dams did not show a significant decrease up to day 10 postpartum. These facts indicate that the two chemical forms of Hg were transferred to the offspring via the breast milk and were distributed differently, depending on the chemical form, to the offspring’s tissues.     

Relationship between occupational exposure to lead and local arterial stiffness and left ventricular diastolic function in individuals with arterial hypertension

Relationship between occupational exposure to lead and frequency of complications in persons with arterial hypertension has been poorly investigated. This study aimed at evaluation of the relationship between occupational exposure to lead and manifestation of an increased local arterial stiffness and left ventricular diastolic dysfunction. The studies included 105 men (mean age: 44.47 ± 9.12 years) with arterial hypertension, treated with hypotensive drugs: group I — men occupationally exposed to lead (n = 53), and group II — men not exposed to lead (n = 52). In echocardiographic examination, the left ventricular diastolic dysfunction was diagnosed significantly more frequently in group I than in group II. In eTracking examination mean values of stiffness parameter (β), augmentation index (AI) and one-point pulse wave velocity (PWV-β) were significantly higher and mean values of arterial compliance (AC) were significantly lower in group I than in group II. The logistic regression showed that in the group of persons with arterial hypertension occupationally exposed to lead a more advanced age, higher blood lead concentration and higher mean values of augmentation index represent independent risk factors of left ventricular diastolic dysfunction. The multifactorial regression showed that amongst persons with arterial hypertension occupationally exposed to lead higher blood zinc protoporphyrin concentration, a more advanced age and higher value of body mass index (BMI) represent independent risk factors of an increased local arterial stiffness. In summary, we should note that in the group of persons with arterial hypertension occupationally exposed to lead the study has demonstrated a significantly more frequent manifestation of left ventricular diastolic dysfunction and an increase in local arterial stiffness.