Rotogravure Printing Research Articles

Metabolite ratio of toluene-exposed rotogravure printing plant workers reflects individual mutagenic risk by sister chromatid exchanges

The study involved a group of 42 printing plant workers and a control group of 45 blood donors. At the working places, the ambient air-toluene concentration amounted from 141 to 328mg/m3. Sister chromatid exchanges (SCEs) were significantly elevated by three units in the exposed group. In this group, the concentration of urinary toluene metabolites was also considerably increased—hippuric acid was four times higher and the o-cresol and p-cresol fractions were twice as high. Results of toluene monitoring of ambient air- or blood-toluene concentrations did not show any relationships with individual SCE. While these SCE values revealed only a weak relationship with the corresponding hippuric acid data, a significant correlation with the cresols, which are known to be more genotoxic than hippuric acid, appeared in highly exposed workers. An attempt was made to consider the individual metabolic balance of toluene excretion products. For that reason individual cresol to hippuric acid ratios were calculated and related to corresponding SCE values. In all investigated subpopulations of the exposed group, this ratio correlated with SCE at a level of high significance. This strong interrelationship is a powerful argument for the genotoxic behavior of toluene. Furthermore, the individual metabolic balance, as a consequence of genetic polymorphism, should be considered in the discussion about genetic risk of toluene.

Psychomotor performance and subjective symptoms at low level toluene exposure

Objectives: Possible effects of long term occupational exposure to toluene below the level of 100 ppm on psychomotor performance and subjective symptoms were investigated in a cross sectional approach. Methods:...

Characterization of publication rotogravure press emission rates and compositions.

Emission compositions and rates were determined during production for a publication rotogravure press room at a large rotogravure printing company. The press room housed a single 4-color, 8-print-stand press, with an 84" paper web. Average press speed was 1800 feet per minute. Data were collected over a 2-day period and included measurements of ventilation, room area concentrations, duct exhaust compositions, amount and composition of inks used, and worker exposures. These data were used with mass balance models that were appropriate for the workspace. Toluene comprised more than 90 percent of the inks and solvents and accounted for more than 90 percent of the press emissions. Average toluene emissions during press operation and press off conditions were 222 kg/hr and 8-38 kg/hr, respectively. The uncontrolled toluene emission on the basis of printed paper throughput was 3 g/m2. Of the total toluene released, 90 percent was captured by the local exhaust ventilation. The measured control efficiency was much lower than the average efficiency of 97 percent for the month of the test reported by the plant. A mass balance model evaluation demonstrated that only the lower efficiency was consistent with measured room concentrations. Using the measured emission rates and actual monthly press on and press off conditions, the difference in efficiency for the plant (10 rotogravure presses) extrapolates to the additional release to the workspace and ambient environment of over 700 tons/yr of toluene.

Mercury Free Determination of Lead by Differential Pulse Anodic Stripping Voltammetry onto Silver-Plated Rotograved Carbon Electrodes

Single-use carbon electrodes, prepared by the rotogravure printing process, serve as a substrate for the nucleation and subsequent growth of silver nuclei. The resulting silver phase permits the underpotential deposition of lead. Associated with a thin layer flow cell, ppb quantities of lead were determined by anodic stripping voltammetry with a satisfactory reproducibility. A lead detection limit of 1 ppb was achieved for an entire experiment time of 120 s without removal of oxygen.

The effect of process parameters on product quality of rotogravure printing

This paper describes an experimental investigation into the process parameter effects on product quality in rotogravure printing. A production printing press was instrumented for the measurement of parameters including strategic temperatures, speeds and web tension. Through-the-run analysis was used to evaluate the fluctuation of the press parameters and the product quality. The trials indicated the parameters where process control is important and allowed the elimination of several parameters, including ink drying, from the main experimental programme. The parameters selected for the main experiments were those most often used for control purposes, or those that were varied between print jobs. Orthogonal array experiments were used, as these allow the simultaneous variation of several parameters and the investigation of interactions between parameters. The experiments were performed using a typical commercial print run once the production of saleable copy had been completed. The analysis of the print quality was carried out in the image areas using spectrophotometry. The experiments highlighted the sensitivity of the process to changes in ink viscosity and the non-linearity of the response. Doctor blade setting was also found to be important, whereas blade load and impression pressure had negligible impact. No interactions were found between any of the parameters investigated. For viscosity change, analysis of the printed image confirmed the importance of hydrodynamic mechanisms, but it was not possible to isolate ink dilution. For doctor blade angular setting, hydrodynamic behaviour appears secondary to cell transport and release mechanisms. This latter mechanism requires further investigation in order to establish a clear understanding.

Mortality in a cohort of toluene exposed employees (rotogravure printing plant workers).

Since the beginning of the 1960s, toluene has been used as a solvent in all German rotogravure printing plants in a high degree of purity. These particular exposure conditions allow the investigation of the potential carcinogenicity of long-term toluene exposure. A historical cohort study was performed that included 6830 German men from 11 plants who were exposed to toluene from 1960 to 1992 in three work areas with different exposure levels. Overall, 466 deaths were observed, which provided a standardized mortality ratio (SMR) of 91.3 for overall mortality. A significantly decreased SMR for total mortality was seen in one of the three work areas (SMR = 67). Mortality from cancer did not differ substantially from the expected level, but in one of the work areas, mortality from cancers of the bone (Ninth Revision of the International Classification of Disease [ICD]-9 170; SMR = 813) and connective tissue (ICD-9 171; SMR = 631) was significantly elevated. In the entire cohort, mortality from lung cancer was increased by about 35% above total mortality, and by about 95% in one work area with low toluene exposure (not statistically confirmed). The SMR for death from alcohol dependence was statistically significantly increased (ICD-9 303; SMR = 314).

Sister chromatid exchanges in rotogravure printing plant workers.

The individual burden of inhaled ambient-air toluene and its link to genotoxic phenomena in exposed printing workers. The influence of toluene on sister chromatid exchange (SCE) was investigated by monitoring of the individual toluene burden of 42 exposed printing workers. Therefore, the urinary hippuric acid (HA) excretion was measured directly after the work shift. The results were compared with those recorded for a control group consisting of 45 blood donors. SCE frequencies were determined from peripheral lymphocytes for both groups. The median HA excretion of the exposed and nonexposed groups amounted to 1.94 and 0.45 g/g creatinine, respectively. For both groups, different SCE rates were detected: 10.13 and 6.84 counts/lymphocyte for exposed and nonexposed persons, respectively. The independence of the measured values proved to be significant at a high confidence level (P = 0.000) for both groups. The influences of smoking and alcohol consumption on SCE as well as on HA values could be clearly separated from those induced by toluene. The results of our study indicate a strong relationship between the individual toluene burden and the genotoxic risk of the exposed persons. Since toluene was used for dilution of the letter-press ink, the influence of ink mist on the genotoxic effects could not be completely excluded.

Toluene-induced hearing loss among rotogravure printing workers.

This study explored the effects of occupational exposure to solvents and noise on the hearing of rotogravure printing workers from São Paulo, Brazil. The study group comprised 124 workers exposed to various levels of noise and an organic solvent mixture of toluene, ethyl acetate, and ethanol. Data on work history, psychosocial aspects of the job, medical history, present health, stress, occupational and nonoccupational exposures to noise or chemicals, and life-style factors were collected through an interview. The participants underwent pure-tone audiometry and immittance audiometry testing. Their exposures to noise and solvents were assessed. Forty-nine percent of the workers had hearing loss. From the numerous variables that were analyzed for their contribution to the development of hearing loss (age, tenure, noise dose, solvent concentrations in air, biological marker for toluene, job category, work and medical history items, smoking, alcohol consumption, work perception scores, nonoccupational exposures), age and hippuric acid (the biologic marker for toluene in urine) were the only variables that met the significance level criterion in the final multiple logistic regression model. The odds ratio estimates for hearing loss were 1.07 times greater for each increment of 1 year of age [95% confidence interval (95% CI) 1.03-1.11] and 1.76 times greater for each gram of hippuric acid per gram of creatinine (95% CI 1.00-2.98). The findings suggest that exposure to toluene has a toxic effect on the auditory system. Further research is needed on the mechanisms underlying the effects of toluene and on the adequacy of current recommended exposure limits.

Practical experience with an industrial biofilter treating solvent vapour loads of varying magnitude and composition

Abstract

Overcoming process delays with decision tree induction

Printers are always seeking higher productivity by increasing their production rates and minimizing process delays. When process delays have known causes, they can be mitigated by acquiring causal rules from human experts and then applying sensors and automated real-time diagnostic devices to the process. However, for some delays the experts have only weak causal knowledge or none at all. In such cases, machine learning tools can collect training data and process it through an induction engine in search of diagnostic knowledge. We have applied a machine learning strategy known as decision tree induction to derive a set of rules about a long-standing problem in rotogravure printing. The induction mechanism is embedded within a knowledge acquisition system that suggests plausible rules to an expert, who can override the rules or modify the data from which the rules were derived. By using decision tree induction to derive process control rules, this system lets experts participate in knowledge acquisition by doing what they do best: exercising their expertise. >

Evaluation of biological monitoring parameters for occupational exposure to toluene

A survey was conducted in a rotogravure printing plant with inhalatory and percutaneous exposure to toluene. Workers (n = 9) were followed for 2 consecutive days and the frequency and duration of skin contact with toluene were monitored. In order to assess percutaneous absorption an airstream helmet was worn during one day. Urine and exhaled air samples were collected simultaneously 5 times each day for toluene (urine and breath) and hippuric acid (urine). The mean (personal air sampling) exposure concentration was between 30 mg/m3 and 600 mg/m3. The best biological monitoring parameter of external exposure (without a helmet) was the concentration toluene in exhaled air 8 h after work (r = 0.99). While wearing the airstream helmet the relationship between external exposure (measured in the helmet) and concentrations in exhaled air and urine deviated from the preceding relations. This was likely the result of the high body burden and not of skin contact with toluene. Skin contact with toluene (usually by cleaning of the hands) was limited to 0-30 minutes a day, with an average of about 5 minutes. During experimental exposure (n = 6) in which the hands were washed with toluene for 5 minutes the toluene in exhaled air (max after 1040 min) clearly demonstrated skin absorption of toluene. The next morning 0.1 mg/m3 toluene was still detectable; this was less than the concentration measured the next morning in exhaled air of workers: between 0.5 and 10 mg/m3.

Urinary excretion of o-cresol and hippuric acid after toluene exposure in rotogravure printing.

In 62 male rotogravure printers, the time-weighted average (TWA) toluene exposure during one workweek ranged from 8 to 496 mg/m3 (median 96). Post-shift urinary excretion of hippuric acid showed a poor correlation with the air toluene concentration. Level of o-cresol excretion ranged from 0.08 to 2.37 mmol/mol creatinine and was associated with the exposure (rS = 0.57, P less than 0.0001), although the variation was considerable. However, this metabolite was significantly influenced by smoking habits, both in the workers (0.34 vs 0.10 mmol/mol creatinine after adjustment to zero exposure for the smokers and non-smokers, respectively; P = 0.03) and in 21 unexposed controls (0.18 vs 0.06 mmol/mol creatinine; P = 0.002). The excretion of these metabolites was followed during vacation, when the workers were unexposed. The shared one-compartment half-time was 44 h (+/- SE 30, 82). After 2-4 weeks of vacation, the concentration of o-cresol was significantly higher for the smokers than the non-smokers (0.14 vs 0.06 mmol/mol creatinine; P = 0.02). No smoking-associated difference was found for the urinary hippuric acid concentration. However, there was an association between alcohol consumption and hippuric acid excretion (P = 0.03); no such difference was shown for o-cresol. These results demonstrate that hippuric acid excretion is unsuitable for biological monitoring of toluene exposure when the exposure level is below 200 mg/m3. Also, in spite of the favourable excretion kinetics, the impact of smoking and the large interindividual variation warrant the same conclusion for o-cresol as a means of monitoring low level exposure in an individual worker.

Kaolin in paper filling and coating

Kaolin is the most extensively used particulate mineral in the filling and coating of paper. It improves paper appearance, which is characterized by gloss, smoothness, brightness and opacity, and of greatest significance, it improves printability. Paper is also filled with kaolin to extend fiber. The characteristics of kaolin that have the greatest influence on the quality of paper are the purity, rheology and particle geometry of the processed mineral. Generally, the most deleterious impurities for brightness of kaolin are iron oxide and titanium oxide minerals. The rheology of kaolin-binder-water suspensions at high solid: liquid ratios (as much as 65%) must be approximately Newtonian for efficient blade coating at speeds as great as 1300 meter/min. Particle geometry, defined as particle size, particle size distribution, particle shape and aggregate structure, has a dominant influence over the rheological character of kaolin slurries, as well as on the properties imparted by the kaolin to filled and coated paper. Increase in the aspect ratio of kaolin, as opposed to increase in surface area, exerts the dominant influence on the increase in low-shear viscosity. Although low-shear viscosities of undelaminated coating grades of kaolin show good correlation with surface area, the relationship breaks down for delaminated grades. Particle packing is believed to be the controlling parameter for viscosity at high rates of shear. Opacity, gloss, printability and, to a lesser extent, brightness of paper imparted by coating and filling with kaolin, are largely functions of particle size and particle size distribution. The strength of coated and filled paper generally decrease with decrease in particle size. An increase in coating void volume generally has a deleterious effect on strength. The principal commercial printing systems today are rotogravure and offset. Although other parameters are important, coating structures containing numerous voids generally give superior rotogravure printing, whereas smooth, relatively ink-impermeable surfaces are generally most favorable for offset printing.

Chromosome aberrations in rotogravure printing plant workers

Chromosome analysis was carried out in peripheral lymphocytes of 3 groups of workers. In 42 rotogravure printers exposed to rotogravure printing dyes and highly purified toluene at working air concentrations in the range of 104–1170 ppm (390–4380 mg/m 3 for 13 years on average, an increased incidence of aberrant cells and chromatid breaks was observed. In 28 office and technical employees of the same plant, more than half of whom worked 2 h daily in the rotogravure workshop, an increased percentage of aberrant cells and chromatid breaks was also found. The difference between the 2 groups working in the printing plant and 32 controls was highly significant. The high incidence of aberrations could be explained by the exposure to toluene, but the influence of rotogravure printing dyes cannot be excluded. Smoking and high air pollution in the urban area were contributing factors in all 3 groups.

Toluene in venous blood during and after work in rotogravure printing.

Toluene exposure was studied in 62 male rotogravure printers, employed in three plants. The exposure level as measured by personal sampling during a week ranged from 8 to 1080 mg/m3 (median 96). The concentration of toluene in venous blood sampled directly after work correlated significantly with the time-weighted average (TWA) for toluene in air during the preceding workshift (n = 57, Spearman's r = 0.84, P less than 0.00001). The post-shift toluene level in venous blood is usable for biological monitoring of exposure. An air level of 100 mg/m3 corresponds to an average blood toluene level of 2.9 mumol/l; an air level of 300 mg/m3 to 8.2 mumol/l. The elimination of toluene is slow. Thus, toluene was detected in most Monday pre-shift blood samples and the levels increased statistically significantly during the work week (median 0.21 versus 0.42 mumol/l, P less than 0.0001). The toluene level in venous blood sampled directly before work on Thursday/Friday was found to be a function of the estimated mean exposure during the work week. In a multiple linear regression analysis, the mean exposure during the week was a good predictor for the concentration of toluene in venous blood before work at the end of the week (n = 52, r = 0.71). Thus, pre-shift blood values at the end of the week can be used as a biological index for the weekly exposure, when the variation of the ambient toluene concentration is known. The slow decrease of toluene in venous blood was followed in six workers for two weeks after cessation of exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiological study on the hepatotoxicity of occupational toluene exposure.

In a cross-sectional study of 181 male workers of a rotogravure printing plant, most of whom were exposed to toluene levels well above the GDR threshold limit values, 55 subjects revealed pathological liver screening values (activities of serum aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase; liver size). The differential diagnostic examination showed in 51 out of these 55 subjects an association with competing factors such as alcohol abuse (78%) and overweight (40%), to a slight extent disorders of fat and carbohydrate metabolism and of the gallbladder. Drug intake did not play any role. The variance and regression analyses of the biochemical data have shown that alcohol significantly and considerably increases the activities of all three enzymes tested. Bodyweight had a similar, but less pronounced, significant effect. On the other hand, in subjects with a higher alcohol intake the activities of liver enzymes in highly toluene exposed subgroups were significantly and clearly lower than among slightly toluene exposed workers.

Response of solvent-exposed printers and unexposed controls to six-hour toluene exposure.

The acute effects of toluene were studied in 43 male printers and 43 control subjects matched according to sex, age, educational level, and smoking habits. The mean age of the subjects was 36 (range 29-50) years. The printers had been exposed to solvents for 9 to 25 years during employment at flexo and rotogravure printing plants, while the controls had no history of solvent exposure. Each subject was exposed once in a climate chamber to either 100 ppm of toluene or clean air for 6.5 h preceded by a 1-h acclimatization period. The effects of toluene were measured from subjective votes with linear analogue rating scales on 16 items, and on the performance of 10 different tests measuring psychomotor skills, perceptual skills, and vigilance. Exposure to 100 ppm of toluene compared with exposure to clean air caused discomfort with complaints of low air quality, strong odor, fatigue, sleepiness, a feeling of intoxication, and irritation of the eyes, nose and throat. Furthermore, the subjects exposed to toluene showed decreased manual dexterity, decreased color discrimination, and decreased accuracy in visual perception. There was no significant difference in the effects of toluene on printers compared to those of toluene on controls, but tendencies toward a greater sensitivity were seen for the printers in two tests.

Commercial printing ink pigmentation Part 3: pigmentation of selected ink systems

Printing inks fall into two more or less distinct rheological classes—highly viscous inks formulated for letterpress, offset, and typographical printing versus relatively fluid inks formulated for flexographic and rotogravure printing.

Les risques du benzène dans l'imprimerie

In two workshops of rotogravure printing, the analysis of air and of certain solvents and inks revealed the existence of important quantities of benzol which were the cause of hematological and other troubles.

Kimball P. Ashley (Halftone)

This chapter describes the rotogravure printing process. The process involves transferring ink, one color at a time, from a cylinder in which a pattern of cells has been engraved to a substrate. Additional colors, each registered to the locations of those printing previously, are added. This multicolored pattern of inks dots on the substrate takes on photographic quality with the halftone printing effect. Dot patterns can combine to appear to the eye to be colors not present in the applied ink. Ink metering involves a doctor blade assembly that wipes excess ink amounts from the cylinder surface to provide careful control of the volume of ink transferred from each cell.