Biological monitoring of workers exposed to N-nitrosodiethanolamine in the metal industry.

Biological monitoring of occupational hazards was performed in workers using cutting fluids containing N-nitrosodiethanolamine (NDELA). The study involved a group of 25 male subjects from some metal factories in central Italy who used cutting fluids with an NDELA content of > or = 5 mg/l (high-exposure group) and a group of 37 males exposed to cutting fluids with an NDELA content < 5 mg/l (low-exposure group). For comparison, we recruited a control group consisting of 37 subjects living in the same area. For all subjects, internal dose (urinary excretion of NDELA, mutagens, and thioethers), early biological effects (sister chromatid exchanges in blood peripheral lymphocytes), and urinary excretion of D-glucaric acid (DGA) as an endpoint product in the glucuronidation pathway were assessed. The results showed that only the workers using cutting fluids with NDELA concentrations of > or = 5 mg/l excreted trace amounts of NDELA in their urine. Urine excretion of mutagens was similar in the two exposure groups and in the controls. High-exposure subjects had a higher mean value of urinary thioethers than low-exposure and control subjects, but no differences were found in urinary DGA or lymphocyte sister chromatid exchange among the three groups. Smoking status increased the mean values of all the biomarkers, and coffee drinking was associated with urinary DGA excretion.     

<Emphasis Type="Italic">N</Emphasis>-Nitrosodiethanolamine urinary excretion in workers exposed to aqueous metalworking fluids

Objective This work was intended to clarify the extent of exposure of workers occupationally exposed to N-nitrosodiethanolamine (NDELA), a carcinogenic nitrosamine, while working with aqueous metalworking fluids (MWFs) formulated with ("nitrite-formulated") or without ("nitrite-free") nitrite and to study the relationships between the nitrite and NDELA content of the MWFs as well as between the concentration of NDELA in MWFs and in urine.Method Pre-shift and post-shift urine samples from 100 workers directly exposed to MWFs in 15 factories were analysed for NDELA with chemiluminescent detection (TEA) according to a previously described analytical procedure. The method was also applied to eight indirectly exposed workers and to 48 unexposed subjects. The NDELA and concentrations in 84 fluids used by the workers were also determined.Results No detectable NDELA could be observed in the control group. The mean post-shift NDELA excretion in workers exposed to "nitrite-formulated" and "nitrite-free" MWFs were 44.6 and 0.4 µg/l, with maxima of 277 and 2.7 µg/l, respectively. According to the correlation between the nitrite and NDELA concentrations in "nitrite-free" MWFs, there is a low probability of fluids exceeding 5 mg/l NDELA when the nitrite content does not exceed 20 mg/l. The NDELA concentrations in the fluids and urine were found to be highly correlated, particularly after correction for creatinine (r=0.917 in post-shift samples). Cutaneous contact probably contributes, at least in part, to the overall body uptake of NDELA.Conclusion Due to clear evidence of urinary NDELA excretion in workers exposed to contaminated MWFs, and despite a lack of knowledge of the human risk following NDELA exposure, levels of NDELA in MWFs should be kept as low as possible. NDELA fluid concentrations of less than 1 mg/l must be considered as the objective to be attained, even if the limit of 5 mg/l is temporarily satisfactory and consistent with a nitrite limit of 20 mg/l that is easy to verify with inexpensive colorimetric tests. "Nitrite-formulated" fluids, still sometimes used, should be prohibited. Meanwhile, the material safety data sheets (MSDS) of commercially available products should be clearly labelled to indicate their nitrite content.     

N-nitrosodiethanolamine in commercial cutting fluids without nitrites.

We have determined the concentration of N-nitrosodiethanolamine (NDELA) in 11 commercial 'nitrite-free' cutting fluids in Sweden in 1989. The concentrations in diluted fluids after use were 0.02-0.51 ppm. The concentrates contained 0.02-17 ppm. There was no correlation between the occurrence of formaldehyde-releasers, boramines or bacteria and the concentrations of NDELA. An additive in one fluid contained 140 ppm NDELA. The concentration of nitrite in the diluted fluids after use varied between 0 and 40 ppm. There was a correlation between the concentration of nitrite and NDELA. It is concluded that the concentration of NDELA can be low if the suppliers check their additives with regard to NDELA and the users check the concentration of nitrite.     

NDELA and nickel modulation of triazine disposition in skin

Cutting fluids can become contaminated with metals (e.g., nickel, Ni) and nitrosamines (e.g., N-nitrosodiethanolamine, NDELA) and there is concern that these classes of contaminants can modulate dermal disposition and ultimately the toxicity of cutting fluid additives, such as irritant biocides (e.g., triazine). Biocides are added to these formulations to prevent bacterial degradation of commercial cutting fluids. The purpose of this study was to assess the dermal absorption and skin deposition of 14C-triazine when topically applied to porcine skin in an in vitro flow-through diffusion cell system as aqueous soluble oil (mineral oil, MO) or aqueous synthetic (polyethylene glycol, PEG) mixtures. 14C-Triazine mixtures were formulated with NDELA and/or Ni, or with a combination of three additional cutting fluid additives; namely, 5% linear alkylbenzene sulfonate (LAS), 5% triethanolamine (TEA) and 5% sulfurized ricinoleic acid. Neither Ni nor NDELA was absorbed during these 8-h studies. However, 14C-triazine absorption ranged from 2.72 to 3.29% dose in MO and 2.29-2.88% dose in PEG with significantly greater triazine absorption in MO than PEG when all additives and contaminates were present. The difference between these two diluents was most pronounced when NDELA and/or Ni were present in cutting fluids. These contaminants also enhanced triazine deposition on the skin surface and skin tissues especially with PEG-based mixtures. In essence, the dermal disposition of irritant biocides could be dependent on whether the worker is exposed to a soluble oil or synthetic fluid when these contaminants are present. Workers should therefore not only be concerned about dermatotoxicity of these contaminants, but also the modulated dermal disposition of cutting fluid additives when these contaminants are present in cutting fluid formulations.     

Mutagenic effects of cutting fluids and components in the Salmonella typhimurium mutagenicity assay

Emulsions of water-soluble cutting fluids (wsCF) are used in large quantities in the metal industry. In order to reduce the costs for use and disposal of these fluids, new technologies are being introduced. Minimist Lubricant Supply (MLS) uses only minimal amounts of cutting fluids. In contrast to conventional wsCF, which are complex multicompound mixtures, MLS cutting fluids are composed of one or two components only, like fatty alcohols and fatty acid esters. The aim of the study was to identify and compare the mutagenic potential of these cutting fluids as a first indicator of a possible hazard of systemic effects after inhalation or dermal absorption of the fluids at the workplace. The Salmonella typhimurium assay (Ames assay) was used as a screening method to detect mutagenic effects of cutting fluids. Conventional wsCF and MLS cutting fluids were tested in the strains TA 98, TA 100, TA 102 and TA 104, in the presence and absence of an external metabolizing enzyme system (rat liver S9-mix), using a preincubation (20 min) test protocol. For MLS fluids, no mutagenicity was found in a concentration range between 1 and 10 mg/plate in the Ames assay. Among five tested conventional wsCF, two were mutagenic in the Ames assay at concentration ranges between 2.5 and 15 mg/plate. In cooperation with the manufacturer, 18 defined components of cutting fluids were tested separately. The results revealed that formaldehyde generators, derivatives of oxazolidine and hexahydrotriazine used as biocides for preservation of the fluids, were mutagenic. Four components were nonmutagenic but cytotoxic, whereas the remaining components displayed no bacterial mutagenicity. The present results show the potential hazard of biocides for workers handling these fluids. An exposure via inhalation and/or dermal absorption could cause an additional risk due to mutagenic ingredients. Under aspects of workers' safety, a further discussion about the use of specific components in cutting fluids is recommended.     

Determination of N-nitrosodiethanolamine in urine by gas chromatography thermal energy analysis: application in workers exposed to aqueous metalworking fluids

 Objective: The aim of this study was to describe a detailed and validated methodology designed for the analysis of carcinogenic N-nitrosodiethanolamine (NDELA) down to sub-μg/l levels in urine and its application to a number of workers exposed to NDELA-contaminated aqueous metalworking fluids (MWF). Methods: Following a work-up procedure based on solid-phase extraction of NDELA, the urinary extracts were analysed without derivatization by gas chromatography on a polar wide-bore column with chemiluminescent detection using a thermal energy analyser (TEA). N-Nitroso-(2-hydroxypropyl)amine was used as an internal standard. The method was applied to 12 workers using “nitrite-free” or “nitrite-formulated” MWF and to 15 unexposed subjects. The NDELA content of the MWF was also determined using a similar, but simpler method able to easily quantify NDELA down to at least 0.1 mg/l. Results: Contamination by NDELA traces of some chemicals used for the sample preparation, particularly ethyl formate, must be carefully checked since it can give rise to false-positive results of up to 1 or 2 μg/l. The response was linear in the range of 0–500 μg/l. Between 0.5 and 10 μg/l, the recovery rate was close to 95%, while repeatability ranged from 12.5 to 6.4% (n = 5). The detection limit was 0.3 μg/l (Signal/noise = 3). No detectable NDELA could be observed in the control workers. There was no significant increase in NDELA levels at the end of shift spot samples from an exposed worker over 1 week. Higher NDELA concentrations were found in two workers (4.3 and 10.7 μg/l) exposed to “nitrite-formulated” fluids (contaminated with 65 and 18 mg NDELA per l, respectively) than in nine workers (range, 0.4–1.3 μg/l exposed to “nitrite-free” fluids with lower levels of NDELA (range, 0.5–6.6 mg/l). Conclusion: The detailed methodology described in this work and applied to a limited industrial situation was found to be suitable for monitoring NDELA in the urine of workers exposed to aqueous MWF. A much larger screening has been undertaken with the aim of obtaining better information on the real exposure of workers sometimes exposed to “nitrite-formulated” fluids that are still used. Received: 8 December 1998 / Accepted: 3 April 1999     

Urinary excretion of mutagens,thioethers and d-glucaric acid in workers exposed to bitumen fumes

Summary The authors carried out biological monitoring of the mutagenic/carcinogenic hazards associated with exposure to bitumen fumes during paving operations, analysing some biological parameters in the urine of a group of exposed workers. The urine samples were studied for mutagenicity by the Ames test and for thioethers concentration. d-Glucaric acid urine excretion was also determined to investigate the enzymatic induction potential of bitumens. Even though, in a previous environmental monitoring phase, a low content of mutagenic/carcinogenic compounds was found in bitumen and air samples, urinary mutagenicity data of exposed workers were statistically higher than those of a group of unexposed subjects. The urinary mutagenicity increased further if exposure to bitumens was associated with cigarette smoking. Thioethers were higher only in subjects exposed simultaneously to bitumens and cigarettes. d-Glucaric acid excretion did not increase significantly. The authors think that this type of coupled environmental and biological monitoring is a valid tool for a better evaluation of the mutagenic/carcinogenic exposure to bitumens or similar complex mixtures.     

Environmental monitoring of mutagenic/carcinogenic hazards during road paving operations with bitumens

Summary Environmental monitoring of mutagenic/carcinogenic hazards associated with occupational exposure to bitumen fumes was performed during road paving operations. Bitumen samples were collected and analysed for polycyclic aromatic hydrocarbons (PAH) content by HPLC and for mutagenicity by the Ames test. The exposure of sixteen road workers to bitumen fumes was studied. Time-weighted average values of bitumen fumes were determined by personal samplers. PAH concentration in the air and the mutagenicity of airborne particulates were also analysed. The results showed that bitumen samples contained low levels of total PAH (g/g) and were not mutagenic. Environmental monitoring showed a low level of exposure to bitumen fumes, which were found to contain only trace levels of PAH and not to be mutagenic. The authors suggest that these workers' exposure to mutagenic/carcinogenic agents is low.     

南通市2008年-2011年市售熟肉制品中亚硝酸盐含量的调查分析

目的:了解南通市市场上熟肉制品中亚硝酸盐含量情况,为政府相关部门提供卫生监管的依据。方法:对市场上抽检的423份样品中亚硝酸盐的监测结果进行统计与分析。结果:亚硝酸盐含量的检出率57.45%,合格率为96.93%,超标率为3.07%,定型包装的合格率高于非定型包装,定型包装的合格率100%,调查中最高含量达3200 mg/kg,超过国家限量标准100倍。结论:南通市市售熟肉制品中存在普遍使用亚硝酸盐的情况,部分样品还存在超标使用和滥用亚硝酸盐的状况,提示应引起相关部门的重视,加大监督力度,以提高熟肉制品的食用安全性。     

Honey increased saliva, plasma, and urine content of total nitrite concentrations in normal individuals

This study investigated effects of oral honey solution on total nitrite, a stable nitric oxide metabolite, in saliva, plasma, and urine samples collected from normal subjects. Fourteen adult healthy volunteers, 25-50 years old, nine males and three females, were enrolled in the study. Total nitrite was estimated in saliva, plasma, and urine after 14 hours of food fasting. Each subject was then asked to drink honey solution (80 g of raw honey dissolved in 250 mL of water). Saliva and blood samples were collected at 1, 2, and 3 hours after ingestion of honey solution for total nitrite assay, while urine samples were collected after 3 hours for total nitrite assay. The mean total fasting nitrite in saliva was 108 +/- 61.3 micromol/L, which was increased to 130 +/- 62.9, 131.2 +/- 59, and 135.1 +/- 64.3 micromol/L at 1, 2, and 3 hours, respectively. Plasma total nitrite was 22.41 +/- 16.22 micromol/L before drinking honey, which was increased to 34.71 +/- 18.13, 29.38 +/- 14.29, and 33 +/- 13.09 micromol/L at 1, 2, and 3 hours, respectively, after drinking honey. Urine total nitrite before drinking honey was 75.8 +/- 54.79 micromol/L, which was increased to 107.8 +/- 70.83 micromol/L 3 hours after ingestion of honey solution. Although not statistically significant, honey solution showed a tendency to increase total nitrite concentration in different biological fluids from humans, including saliva, plasma, and urine.     

Health effects of oil mists: a brief review

Metal cutting/grinding fluids are of three basic types: straight oil (insoluble), oil-in-water emulsions (soluble) and synthetic/semisynthetic. All contain a variety of additives to improve performance. Human exposure occurs primarily by direct skin contact with the liquid or by skin and respiratory contact after fluid misting. Dermatitis caused by primary or direct skin irritation is the most prevalent health effect of exposure to cutting fluids. Occasionally allergic dermatitis is seen which is related to the development of sensitization to one or more of the additive components. Recent studies indicate that long-term exposure to cutting fluids does not result in increased incidences of lung cancer, urinary bladder cancer, gastrointestinal cancer, or death from non-malignant respiratory diseases. Long-term exposure to certain cutting fluids, however, is believed to have resulted in certain types of skin cancer, especially scrotal cancer. It is likely that these carcinogenic responses were caused by contact with polycyclic aromatic compounds (PCA) of 3-7 rings. Modern base oils which are severely refined have very low levels of PCA, are not carcinogenic in animal bioassays, and are unlikely to be carcinogenic in man. This is not necessarily true for re-refined oils which may contain significant levels of PCA and polychlorinated biphenyls derived from comingling used cutting oils with used engine oils and transformer oils. Cutting oils, themselves, generally do not accumulate significant levels of carcinogenic PCA during use. Additives, in theory, can cause a variety of health effects either directly or through the generation of reaction products such as nitrosamines. In actual use, adverse health effects appear to be limited to occasional instances of allergic contact dermatitis. Nitrosamines are extremely carcinogenic in test animals; although no human cancer cases directly attributable to nitrosamine contamination have been observed, nitrosating agents and amines should not be combined in cutting fluid formulations. It is difficult to anticipate or predict the potential toxicity of a particular cutting fluid formulation because of the presence of variable amounts of proprietary additives which, themselves, are often complex reaction mixtures. Thus, each additive and final formulation must be evaluated on a case by case basis to appropriately assess potential health hazards.     

深圳市腌腊制品中亚硝酸盐含量的调查

目的了解深圳市市场上腌腊制品中亚硝酸盐污染状况,为相关部门提供监管依据。方法采用国家食品卫生检验标准方法（GB／T5009133—2003）即食品中亚硝酸盐与硝酸盐的盐酸萘乙二胺比色法对市场上抽检108份腌腊制品中亚硝酸盐含量进行测定,对测定结果进行分析。结果亚硝酸盐超标率为22．2％,其中腊猪耳、腊兔、麻辣肠、腊鸡和猪头肉类亚硝酸盐平均含量分别高达71．0、56．7、46．2、37．6和35．9mg／kg。不同类样品（腊家禽、腊兔、腊猪肉及内脏、腊牛肉、腊兔肉）的亚硝酸盐含量和超标率差别有统计学意义（χ^2=102．79,P〈0．01）。结论市售腌腊制品中亚硝酸盐滥用情况比较普遍,应引起有关部门重视。     

山西省出生缺陷高发区居民饮水中硝酸盐和亚硝酸盐含量研究

目的了解山西省出生缺陷高发地区饮水中硝酸盐和亚硝酸盐含量。方法选择山西省太原市、太谷县和平定县作为研究现场,采集当地居民不同类型的饮用水测定硝酸盐和亚硝酸盐含量。结果研究地区饮水中硝酸盐平均含量为3·5mg/L,有4·0%的样品超过我国的饮用水卫生标准。井水中的硝酸盐含量(5·1mg/L)高于自来水(2·7mg/L)。饮水中亚硝酸盐平均含量为0·004mg/L,以泉水含量最高(0·015mg/L)。结论研究地区居民饮水中硝酸盐和亚硝酸盐含量并没有显著高于文献报道的其它地区。饮水中硝酸盐和亚硝酸盐暴露在山西省出生缺陷高发中的作用可能不大。     

Genotoxicity of PM10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

The variation in the genotoxic potency of PM10 in vitro in relation to the particle source type was investigated. Particles were collected at one urban, one rural, and one industrial site in Flanders. Genotoxicity was assessed using four different in vitro test systems exposed to PM10 in suspension and to the organic extracts of PM10. Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test. In addition, the Comet assay and Micronucleus test were performed using human blood cells. Results show that exposure to PM10 and the organic extracts from both urban and industrial areas causes significant genetic damage. The Salmonella mutagenicity test was most suitable for the screening of PM10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes. Clear dose-response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter. The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m3. Results obtained in this study suggest that PM10 causes DNA damage and mutations. The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.     

DNA-based methodologies for rapid detection, quantification, and species- or strain-level identification of respiratory pathogens (Mycobacteria and Pseudomonads) in metalworking fluids

Mycobacteria and pseudomonads occurring in modern metalworking fluids (MWF) have been implicated in occupational health hazards as causal agents for hypersensitivity pneumonitis (HP) and other respiratory illnesses in machine workers exposed to these fluids and their aerosols. Unlike the conventional cultural and biochemical methods, which are often slow and ambiguous and detect only culturable cells, DNA-based methods offer a time-saving alternative for reliable detection and identification of both culturable and nonculturable bacteria in MWF and for selective quantification of individual genera of pathogens of interest in these fluids. This is the first report on DNA-based direct detection of mycobacteria and pseudomonads in MWF without culturing. Genus-specific PCR approach was successfully applied for screening of field MWF samples originating from different industrial users for detection of mycobacteria or pseudomonads including both culturable and nonculturable cells. PCR in combination with amplicon DNA sequencing led to the identification of Mycobacterium chelonae, Pseudomonas nitroreducens, and an undefined Pseudomonas species from these fluids. Genome fingerprinting by pulsed-field gel electrophoresis (PFGE) on Mycobacterium isolates further showed that the isolates represented three strains of M. chelonae although the possibility of one of the strains being clonal with M. immunogenum cannot be excluded. In parallel efforts, a quantitative competitive PCR method developed based on the Pseudomonas-specific PCR was applied to quantify total P. fluorescens cells in contaminated metalworking fluid and MWF aerosol without culturing. The DNA-based protocols developed in this study will allow rapid screening of field MWF samples for the presence of both culturable and nonculturable cells and thus facilitate effective fluid management and timely exposure assessment.     

Increases in polycyclic aromatic hydrocarbon content and mutagenicity in a cutting fluid as a consequence of its use

Summary The aim of this study was to evaluate the relationships between the length of time a cutting fluid was used, its content in polycyclic aromatic hydrocarbons (PAHs) and its mutagenic potential. The PAH concentrations were determined by means of a high-resolution gas chromatograph-mass spectrometer in samples of new cutting fluid and in samples used for 3, 6 and 9 months. The following PAHs were measured: phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene + triphenylene, benzo [e] pyrene, benzo [a]-pyrene and perylene. Mutagenicitiy assays were carried out on the aforementioned samples using the Ames test. Salmonella typhimurium TA98 was used as an indicator to show up mutagens capable of inducing frame-shift genetic changes, and Escherichia coli WP2 uvrA was used as an indicator to detect mutagens capable of inducing base pair genetic changes. The mutagenic tests were carried out with and without microsomial activation, using 1:1, 1:10, 1:20 and 1: 50 dilutions of cutting fluid samples. An increase in the concentrations of total PAHs over time was observed in the samples of cutting fluid used for 3, 6 and 9 months. The highest percentage increase in PAH concentrations was observed in the 6-month-old sample (10 times the initial concentration, from 45 to 411.8 g of oil). None of the samples were mutagenic to S. typhimurium without metabolic activation or to E. coli with and without metabolic activation. All samples except for the 1:1 diluted sample showed moderate but significant mutagenic activity in the S. typhimurium test with metabolic activation. Mutagenicity rose to its highest levels (similar to those observed with the mutagenic compound 2-acetylaminofluorene, which was used as a positive control) in the 9-month-old sample and in the 6-month-old 1:20 and 1:50 diluted sample. This study shows an increase in the PAH concentrations and mutagenicity of cutting fluids following prolonged use. In order to minimize the risk caused by such an increase in PAH content, it is recommended that the cutting fluid be changed at least every 6 months.     

Occupational health hazards among health care personnel working in public health facilities in Bhubaneswar,India

Background

Health care personnel working in public health facilities comprise a major part of the health care workforce in India and are exposed to a variety of workplace hazards.

Aim

To assess the occupational health hazards and associated risk factors among health care personnel working in public health facilities in Bhubaneswar.

Subject and methods

A cross-sectional study was conducted involving 172 health care personnel working in 22 urban primary health centers and four community health centers in the Bhubaneswar Block of the Khordha district in the state of Odisha, during the period from January to December 2017. Relevant data were collected using a semi-structured interview schedule.

Results

Overall, 143 (83.1%) of the participants reported experiencing occupational health hazards, with 89 (51.7%) encountering biological hazards and 130 (75.6%) experiencing non-biological hazards. Stress (38.9%), assault (38.4%), needlestick injury (34.3%), and direct contact with contaminated specimens/body fluids (32.6%) were the most frequently experienced occupational hazards. Multivariate regression analysis revealed that female gender, health care personnel other than doctors, working overtime, dissatisfaction with workplace atmosphere, and not using the necessary personal protective equipment (PPE) were independent predictors for experiencing a biological hazard. Similarly, female gender, presence of family conflict, and not using the required PPE were found to be independent predictors for experiencing non-biological hazards.

Conclusion

Health care personnel in public health facilities experience multiple hazards in their workplaces. Results indicate the need for designing and implementing strategies to promote the occupational health of this important section of society.

     

2009-2011年宜宾市部分食品中亚硝酸盐和二氧化硫监测

目的 了解宜宾地区食品中亚硝酸盐和二氧化硫的污染状况.方法 于2009-2010年在宜宾市主要超市和农贸市场随机采集各类样品,依据GB/T5009.33-2003和GB/T5009.34-2003对亚硝酸盐和二氧化硫进行检测.结果 43份样品中,有10份样品亚硝酸盐超标,超标率为23.3％,主要是酱卤肉超标,含量在0.037 ～0.270g/kg,最高超标9倍.46份样品中有8份样品二氧化硫超标,超标率为17.8％,主要是竹笋超标,含量在2.13 ～6.76g/kg,最高超标16.9倍.结论 在宜宾市部分食品中亚硝酸盐、二氧化硫污染仍相当严重,对人体健康存在威胁.     

2014-2015年清远市佛冈县结直肠癌筛查结果及危险因素分析

目的 了解佛冈地区的结直肠癌(CRC)患病情况并探讨其影响因素。 方法 在佛冈县随机抽选48个村或社区作为调查点。先统一发放调查问卷以确定高危人群,然后以粪便隐血试验作为初筛。初筛阳性者以结肠镜检作为复筛以确诊,并采用logistic回归分析影响CRC发生的因素。 结果 筛查目标为47 400人,回收有效问卷34 286份,顺应率为72.33%;接受初筛26 572人,阳性1 662人,阳性率6.25%;接受结肠镜检980例,发现结直肠癌35例(3.57%);高亚硝酸盐(OR=2.073)、高脂饮食(OR=2.462)和胆囊结石(OR=2.659)为CRC的危险因素,高膳食纤维(OR=0.637)为保护因素。 结论 结直肠癌筛查能够有效地从无症状人群中找到结直肠癌患者,利于早期治疗,提高预后。佛冈地区居民的CRC筛查依从性较低,应注意加强健康教育。     

Mutagenic/carcinogenic hazards in a cold-rolling steel plant exposed to mineral oils: environmental monitoring phase

Summary A survey was carried out in a cold-rolling steel plant exposed to mineral oils to study the mutagenic/carcinogenic hazards, following a coupled environmental/biological monitoring. The present paper deals only with the environmental phase by determining polycyclic aromatic hydrocarbons (PAH) and applying a mutagenicity test (Ames test), and includes the following steps: (a) work process and environment study; (b) sampling and analysing mineral oils before and after use (PAH determination and mutagenicity analysis); (c) sampling and analysing oil mist (TWA determination, PAH determination and mutagenicity analysis). The results showed that: (1) both unused and used (recycled) mineral oils contained only trace amounts of PAH and were not mutagenic; (2) the TWA concentrations of oil mists were lower than the TLV (< 5 mg/m³); (3) oil mists contained only trace amounts of PAH and were not mutagenic. The authors suggest that these results could be due to the moderate temperature of the oil during the work process and that there is a relationship between low PAH content and absence of mutagenicity in the oils and air samples.