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This work is focused on the checking of the correctness of the brazing process of honeycomb seals to stationary elements of aircraft turbine engines. It describes this process, paying attention to the aspects that have a fundamental impact on whether the seal will be brazed to the base as required, or whether unacceptable areas of non-brazing will appear. The aim of the study was to check the possibility of using the ultrasonic method to check the correctness of the brazing process of honeycomb seals and to compare the tests carried out using this method with the mostly used visual tests. The research carried out as part of the work showed very well that there are reasons to use the ultrasonic defectoscopy method to test the correctness of the brazing process of honeycomb seals in the elements of aircraft engines. This method also makes it possible to automate the checking process, fully document it and objectively assess the correctness of the connection. The results obtained in the study provide a very good starting point for further research, the aim of which will be to implement the ultrasonic defectoscopy method for testing the correctness of brazing honeycomb seals into practice in industrial conditions.

Objectives: Although some of the exposures in aluminum (Al) smelting have been well characterized, and respiratory disorders in aluminum production workers are well known, the relationship between internal aluminum loads and appropriate lung biomarkers have not been elucidated. The aim of our work was to carry out a comprehensive investigation in workers employed in the Aluminum Foundry Casting Department with special reference to currently existing hygiene standards, known as threshold limit values (TLV) based on aluminum effects on the respiratory system. The measurement of serum anti-inflammatory Clara cell protein (CC16) was employed as a peripheral marker of the lung epithelium function., Materials and Methods: A group of 50 casting smelters, 5 locksmiths, 11 sawyers and auxiliary workers exposed to dust containing 14% of aluminum, and a group of 42 controls were examined. Respiratory function tests were performed and forced volume capacity (FVC), forced expiratory volume in 1 s (FEV1), forced expiratory volume in the first percent (FEV1%), forced expiratory flows in 50% VC (FEV50), and markers of foundry workers' exposure and body burden, Al concentration in the breathing zone, blood and urine, biomarkers of the effects of exposure, concentration of CC16 and hyaluronic acid (HA) in serum were determined in all examined workers. Additional measurements comprised determinations of serum iron (Fe) levels, myeloperoxidase (MPO), eosinophil cationic protein (ECP), immunoglobulin E (IgE), glutathione S-transferase (GST), and superoxide dismutase (SOD) activity in erythrocytes., Results: The group of casting smelters was characterized by the highest levels of aluminum in urine (Al-U) (43.7 microg L(-1)), high levels of MPO, ECP and IgE, high SOD activity, low CC16 levels, and low activity of GST. Lower Al-U excretion was observed in locksmiths (35.2 microg L(-1)) and sawyers (21.7 microg L(-1)). Serum CC16 proved to be the most sensitive biomarker, showing high inverse relationship with serum Al (Al-S) concentrations in casting smelters (p = 0.006)., Conclusions: The study showed that in conditions of occupational exposure, dusts containing Al2O3 < 1 mg m(-3) cause changes in the respiratory system and biomarkers in serum, especially in CC16, connected with altered functioning of this system. Changes in concentrations of the examined biomarkers and also in respiratory parameters of the study subjects were observed when Al-U concentration was > 40 microg L (-1).

Background: The authors present the results of medical examinations of workers employed in an aluminum electrolysis plant with occupational exposure to aluminum dust, polycyclic aromatic hydrocarbons, and magnetic field., Methods and Materials: The study covered a selected group of 39 male workers (mean age, 44,9; SD = 7.5 years; range 29-55 years) involved in the aluminum production. Their employment duration ranged between 5 and 32 years (mean, 17.8; SD = 6.7 years). Urine aluminum concentrations in workers ranged from 8.9 to 70.2 microg/g creatinine (mean, 31.72; SD = 18.3 microg/g creatinine). Urine 1-hydroxypyrene concentrations recorded in workers ranged from 0.67 to 10.09 microg/g creatinine (mean, 3.42; SD = 2.1 microg/g creatinine). The control group consisted of 39 men matched by gender, age and work shifts., Results: Clinical symptoms, such as headache (46.2%), increased emotional irritability (66.7%), concentration difficulty (25.6%), insomnia (30.8%), hypersomnia (15.4%), and mood lability (10.3%) predominated among functional disorders of the nervous system in workers chronically exposed to chemical and physical factors. The objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In EEG recordings, classified as abnormal, paroxysmal changes were most common (20.5%)., Conclusions: The authors emphasized great difficulty in evaluating the combined effects of toxic and physical factors exerted on the nervous system.

Background: Studies conducted to assess aluminum (Al)-induced toxicity to humans and environment. It has been implicated that Al is involved in the etiology of Alzheimer's disease and other neurodegenerative disorders, though this is controversial. The aim of the present study was to assess Al effects on the nervous system functions in workers chronically exposed to this metal., Methods and Materials: The study covered a selected group of 67 male workers (mean age, 38.7 +/- 10.3 years; range 23-55 years) involved in aluminum production. Their employment duration ranged between 2 and 34 years (mean, 14.6 +/- 8.9 years). Aluminum oxide (Al2O3) concentrations varied from 0.2 to 1.95 mg/m3 (arithmetic mean, 0.40 mg/m3, geometric mean, 0.35 mg/m3, SD = 0.29). Urine aluminum concentrations found in smelters ranged from 8.5 to 93.0microg/l (mean, 42.9 +/- 20.5 microg/l). The control group consisted of 57 men non-occupationally exposed to Al matched by gender, age and work shifts., Results: Clinically, headache (41,8%), increased emotional irritability (56,7%), concentration difficulty (22,4%), insomnia (22,4%) and mood lability (14,9%) predominated among functional disorders of the nervous system in workers chronically exposed to Al. The objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In EEG classified as abnormal, generalized and paroxysmal changes were most common. Examinations of visual evoked potentials (VEP) revealed abnormalities, primarily in the latency of the response evoked., Conclusions: The results of this study suggest that exposure to Al2O3 at concentrations within MAC values induces subclinical effect in the nervous system.

Background: The aim of this work was to assay the concentration levels and composition of welding fumes, released during flux cored arc welding, to assess exposure of welders., Materials and Methods: Concentrations and welding fume components, such as iron, manganese, chromium (including the soluble and chromium VI), nickel, copper, calcium, aluminium, barium, and fluorides (including hydrogen fluoride) were determined in the air of six industrial plants (shipyards, mechanical engineering plants and a power station) at the breathing zones of the welders who used 10 types of wires during flux cored arc welding. The following determination methods were used: gravimetry (fumes), AAS (metals), and spectrophotometry (chromium VI, fluorides--including hydrogen fluoride)., Results: The results made it possible to determine the relationship between concentrations of welding fume and its elements, and to assess worker's exposure. Time weighted average concentrations of the welding fumes and its elements at the worker's breathing zone were: mg/m3: dust 0.2-24.3; Fe 0.2-6.7; Mn 0.01-1.8; Cr 0.004-0.5 (mainly Cr III); Ca 0.004-2.5; Ni < or = 0.004; Cu < 0.002-0.05; Al < 0.14-0.4; Ba < 0.14; F- 0.07-0.43., Conclusions: The welders using some types of flux cored welding wires worked in conditions harmful to their health owing to the considerably exceeded TLV value for fume and MAC values for manganese, and occasional slightly excessive MAC values for calcium and iron.

Objectives: The aim of the present study was to assess the effects of aluminum (Al) on the nervous system functions in workers chronically exposed to Al., Materials and Methods: The study covered a selected group of 67 male workers (mean age, 38.7 SD 10.3 years; range 23-55 years) involved in the Al production. Their employment duration ranged between 2 and 34 years (mean, 14.6 SD 8.9 years). Aluminum oxide (Al203) concentrations varied from 0.13 to 1.95 mg/m3 (arithmetic mean, 0.40 mg/3, geometric mean, 0.35 mg/m3 SD 0.29). Urine Al concentrations found in smelters ranged from 8.5 to 93.0 microg/l (mean, 42.9 SD 20.5 microg/l). The control group consisted of 57 men non-occupationally exposed to Al, matched by gender, age and work shifts., Results: Clinically, headache (41.8%), increased emotional irritability (56.7%), concentration difficulty (22.4%), insomnia (22.4%) and mood lability (14.9%) predominated among functional disorders of the nervous system in workers chronically exposed to Al. Objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In the EEGs classified as abnormal, generalized and paroxysmal changes were most common., Conclusions: The results of this study suggest that exposure to Al203 at concentrations below MAC values induces subclinical effect in the nervous system.

The objective of this study was to evaluate occupational exposure to welding fumes and its elements on aluminum welders in Polish industry. The study included 52 MIG/Al fume samples and 18 TIG/Al samples in 3 plants. Air samples were collected in the breathing zone of welders (total and respirable dust). Dust concentration was determined gravimetrically, and the elements in the collected dust were determined by AAS. Mean time-weighted average (TWA) concentrations of the welding dusts/fumes and their components in the breathing zone obtained for different welding processes were, in mg/m3: MIG/Al fumes mean 6.0 (0.8-17.8), Al 2.1 (0.1-7.7), Mg 0.2 (< 0.1-0.9), Mn 0.014 (0.002-0.049), Cu 0.011 (0.002-0.092), Zn 0.016 (0.002-0.14), Pb 0.009 (0.005-0.025), Cr 0.003 (0.002-0.007), and TIG/Al fumes 0.7 (0.3-1.4), Al 0.17 (0.07-0.50). A correlation has been found between the concentration of the main components and the fume/dust concentrations in MIG/Al and TIG/Al fumes. Mean percentages of the individual components in MIG/Al fumes/dusts were Al: 30 (9-56) percent; Mg: 3 (1-5.6) percent; Mn: 0.2 (0.1-0.3) percent; Cu: 0.2 (< 0.1-1.8) percent; Zn: 0.2 (< 0.1-0.8) percent; Pb: 0.2 (< 0.1-1) percent; Cr: < 0.1 percent. The proportion of the respirable fraction in the fumes and their constituents varied between 10 percent and 100 percent. The results showed that MIG/Al fumes concentration was 1.2 times higher than the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV), and the index of the combined exposure to the determined agents was 2.3 (0.4-8.0), mostly because of high Al2O3 contribution. The background concentrations of the components (ca. 5-10 times lower than those in the breathing zone of the welders) did not exceed the Polish MAC value. The elemental composition of total and respirable fume/dust may differ considerably depending on welding methods, the nature of welding-related operations, and work environment conditions.

The aim of the study was to assess toxic metal exposure in workers performing soldering and brazing operations. The study group included workers of three plants manufacturing electronic systems, household equipment and electric motors. Membrane filters were used to collect 50 air samples, including personal 8-h samples to assess average weighed concentration of soldering and brazing fumes and their elements, and to assay respirable dust and "background" or "area" samples. After testing by gravimetry, the filter with collected sample was mineralized with concentrated HCL/HNO3 and 10 ml sample solution in 32% HCL/4% HNO3 was prepared according to OSHA ID-206. Atomic absorption spectrometry was used to assess the contents of lead (Pb), tin (Sn), copper (Cu), zinc (Zn), antimony (Sb), silver (Ag) and manganese (Mn) in the sample solution. The quantitative analysis revealed that time-weighed average (TWA) of fume concentrations were: soldering fume < 0.5-1.1 mg/m3, Cu < 0.003-0.034 mg/m3, Pb < 0.014-0.037 mg/m3, Sn < 0.15 mg/m3, Sb < 0.035 mg/m3; brazing fume < 0.5-0.8 mg/m3, Cu < 0.003-0.038 mg/m3, Zn < 0.003-0.025 mg/m3, Pb < 0.014-0.023 mg/m3, Ag < 0.014 mg/m3, Sn < 0.15 mg/m3, Mn < 0.07-0.12 mg/m3. The results show that on the day of measurements, working conditions at solderer/brazer workplaces were safe, i.e. relevant MAC values were not exceeded.

The nervous system is the major target of the toxic effect of manganese (Mn) and its compounds. Nowadays, neurological diagnostics is directed towards early detection of symptoms and abortive forms, and the cases of serious damage of the nervous system are no longer reported. The aim of the present study was to assess the effects of manganese on the functions of the nervous system in workers exposed to this metal in the ship and electrical industries. The study covered a selected group of 75 male workers (mean age 39.17 yr +/- 9.79; range 20-56 yr), including 62 welders and fitters, as well as 13 workers involved in the battery production. Their employment duration ranged between 1 and 41 yr (mean 17.5 yr +/- 10.81). During the welding process the air Mn concentrations varied from 0.004 to 2.67 mg/m3 (arithmetic mean, 0.399 mg/m3; geometric mean, 0.154 mg/m3; standard deviation, 0.586). Of the 62 workers, 30 worked in the area with exceeding MAC value of 0.3 mg/m3. At the battery production workposts, Mn concentrations fell within 0.086-1.164 mg/m3 (arithmetic mean, 0.338 mg/m3, geometric mean, 0.261 mg/m3; standard deviation, 0.292). The values of current Mn exposure in the study group fell within the range below 0.01 and 2.67 mg/m3 (arithmetic mean, 0.4 mg/m; geometric mean, 0.15 mg/m3). Of the 13 subjects, 6 worked at the Mn air concentration exceeding MAC values. In the exposed group, the values of cumulated exposure index ranged from 0.008 to 35.52 (arithmetic mean, 8.045; geometric mean, 4.615; standard deviation, 6.562). The control group consisted of 62 men non-occupationally exposed to Mn, matched by sex, age and work shift distribution. Clinically, the increased emotional irritability, dysmnesia, concentration difficulties, sleepiness and limb paresthesia predominated among the disorders of the nervous system functions in workers chronically exposed to manganese. Neither in the central nor in the peripheral nervous system, the objective examinations revealed organic lesions that could provide grounds for diagnosing toxic encephalopathy or polyneuropathy. Generalized and paroxysmal changes were the most common recordings in the abnormal electroencephalography. Visual evoked potentials examinations showed abnormalities in the response evoked, which could be a signal of the optic neuron disorders and their significant relationship with cumulated exposure. The results of the study demonstrate that Mn exposure within the range of <0.01-2.67 mg/m3 (arithmetic mean, 0.4 mg/m3; geometric mean, 0.15 mg/m3) induces subclinical effects on the nervous system.

The objective of this work was to select optimal methods for determination of toxic gases (NOx, NO2, CO, CO2, O3) and to evaluate occupational exposure of welders to those gases. The survey covered workers employed in shipyards, and other metal product fabrication plants engaged in welding mild and stainless steel by different techniques (manual metal are, metal active gas, tungsten inert gas welding; gas, plasma, laser cutting and resistance welding). Personal and stationary air samples were collected to determine time weighted average (TWA) and short-term concentrations of gases. For determination of nitrogen oxides the following analytical techniques were employed: spectrophotometry with collection on liquid and solid sorbents and ion chromatography with collection on solid sorbents. All the gases were determined also by automatic or direct reading methods: flow or diffusion detector tubes and photometric and electrochemical analyzers. The determined TWA concentrations were below respective Maximum Allowable Concentrations (MAC) but exposure limits for short term exposure were exceeded in some cases. The average NO2 i NOx ratio was 1:4. According to Polish regulations regarding the MAC value for nitrogen oxides the analytical method should enable determination of total NOx by either direct or indirect simultaneous determination of both NO and NO2. The applicability of the spectrophotometric method of analysis of atmospheric NOx to determination of low NOx concentrations at welders working posts has been confirmed.

Dissemination of individual welding methods, as well as assessment of welding fume and gas emissions and their physical properties, chemical composition and related difficulties in hygiene evaluation of working conditions are discussed.

Exposure of MMA/Plasma/Cu welders to fumes and soluble and insoluble Cu was assessed. Mean weighted concentrations of dusts/fumes and copper compounds at the welders' breathing zone were: 3.1 mg/m3 (0.7-7.6 mg/m3) for fumes; 0.08 mg/m3 (0.02-0.17 mg/m3) for soluble Cu; and 0.39 mg/m3 (0.08-0.76 mg/m3) for insoluble Cu. Correlation was found between the concentration of Cu compounds and fume/dust concentrations (r = 0.55 MMA/Plasma/Cu; r = 0.93 MMA/Cu). The mean percentage of copper in fumes/dusts was 17 (9.5-28.5%). Our results show that copper welding may pose a hazard to the welders' health. The index of combined exposure to determined agents was 1.2 (0.3-2.6), including soluble Cu (0.8) and insoluble Cu (0.4). The proportion of respirable fraction of fumes and their components varied between 40-80%. The background concentrations of the components (about 6 times lower than those in the welders' breathing zone) did not exceed the MAC value.

A study was undertaken to assess the relationship between inhalation exposure to arsenic in copper smeltery workers and urinary excretion of total inorganic arsenic metabolites (Asitm), including inorganic arsenic (Asi), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The methods applied made it possible, in principle, to determine all forms of airborne arsenic and to eliminate the influence of seafood-derived organoarsenicals on the level of urinary Asitm. Air samples were collected on the second day of work after the weekend break. Urine samples were collected just after shift-end on the same workday. The time-weighted average (TWA) concentrations of arsenic in the workers' breathing zone varied between 1 and 746 microg/m3 and Asitm concentrations in urine between 2 and 850 microg/l (s.g. 1.024). The urine samples with a specific gravity of lower than 1.010 and higher than 1.030 were not considered; neither were those subjects with an Asitm excretion efficiency of higher than 100% of the dose absorbed during the day of measurement. In total, 53 air samples and corresponding urine samples were obtained. The correlation coefficient between the airborne arsenic concentration in microg/m3 (X) and the concentration of urinary Asitm in microg/l, s.g. 1.024 (Y), was 0.723. The relation between the two variables can be presented using the following formula: Y = 6.29 x X0.616. According to the findings of this study, as well as the results of three other studies based on similar principles, the daily exposure to arsenic concentrations of 10 microg/m3 and 50 microg/m3 led to concentrations of Asitm in urine of about 30 microg/l and 70 microg/l (s.g. 1.024), respectively.

On the basis of an external quality control of nitrogen dioxide measurements in the atmospheric air (emmission), the preparation of control material, its evaluation and durability are presented. The results of the control test carried out in the spring 1995 is also discussed.

Increased levels of Cr discharged with urine after working shift, Cr-U (arithmetic mean 15.8 mu g/g creatinine), and Cr buildup during working shift, DeltaCr-U (arithmetic mean 3.8 mu g/g creatinine), were observed in 15 MMA/SS welders exposed during the working week to welding fumes containing Cr VI (33-56%) - mainly soluble (87%) and Cr III (44-67%) - mainly insoluble (72%). The highest correlation coefficients were obtained for DeltaCr-U vs. Cr total (r = 0.58), Cr VI (r = 0.56) and soluble Cr III in the air. Increased DeltaCr-U value for exposures at MAC Cr VI (16.8 mu g/g creatinine) was demonstrated in welders employed longer than 7 years and exposed to Cr VI below MAC level, which might suggest that the duration of employment affects that value within the low range of concentration of Cr VI in the air (< 0.03 mg/m3). Nevertheless, linear relationship between DeltaCr-U for exposures to Cr VI at MAC levels and duration of employment was not confirmed for wide range of air Cr VI (0.005-0.4 mg/m3). Similar DeltaCr-U values at MAC for Cr VI (6.4 and 6.6 mu g/g creatinine) were obtained for all welders, and those employed over 7 years, respectively, which may suggest that this parameter can be misleading.

For the years 1987-1990 160 individual samples of manual metal arc stainless steel (MMA/SS) welding fumes from the breathing zone of welders in four industrial plants were collected. Concentrations of soluble and insoluble chromium (Cr) III and Cr VI compounds as well as of some other welding fume elements (Fe, Mn, Ni, F) were determined. Concentration of welding fumes in the breathing zone ranged from 0.2 to 23.4 mg/m3. Total Cr amounted to 0.005-0.991 mg/m3 (including 0.005-0.842 mg/m3 Cr VI). Total Cr content of fumes varied from 0.1 to 7.4%. The distribution of particular Cr compounds was: 52.6% soluble Cr (including 50.7% Cr VI), 65.5% total Cr VI, and 11.4% insoluble Cr VI. The results obtained indicate that MMA/SS welding is a process that could be highly hazardous to human health. Evaluation of occupational exposure has shown that MMA/SS welders may exceed the admissible concentrations of soluble and insoluble Cr VI forms as well as of Mn and Ni. In the plants investigated the sum of the ratios of concentrations of particular welding fumes in the breathing zone of welders exceeded corresponding maximum allowable concentration values by 24 times (including 17 times for total Cr VI). Due to the variety and changeability of particular parameters occurring in the working environment, the composition of MMA/SS welding fumes (in the welder's breathing zone) is so variable that it is not possible to assess the exposure by means of one universal exposure indicator (maximum additive hygienic limit value). The evaluation should be based on the results of measurements of concentrations of particular elements in welding fumes.

The work verifies data gathered by Occupational Hygiene departments of Sanitary-Epidemiological Stations about workers exposure to chromium compounds in the processing of chrome iron ore. Research showed that 7 plants were involved in the processing of chrome iron ore and that the number of workers directly employed in the process amounted to 215-230. About 150 workers were exposed to high concentrations of chromium compounds which exceeded hygienic standards. All of them were employed only in metallurgical plants. The remaining 80-100 workers subjected to the study exposed to relatively low chromium concentrations were employed in chemical plants and refractory materials plants.

The arterial blood pressure, lipid content in serum and some organs, cadmium level in blood, aorta wall, lung and liver have been examined in rats repeatedly exposed to cadmium oxide fume 5 hours daily, 5 days a week, during 6 months. The blood pressure in rats exposed to cadmium oxide at concentration 0.02 mg Cd/m3 and 0.16 mg Cd/m3 was not changed, but it was slightly lowered at concentration 1.0 mg Cd/m3, which has been found lethal for rats. The concentration of total cholesterol, phospholipids and cholesterol esters in serum of female rats exposed at concentration of 0.16 mg Cd/m3 for 3 months was decreased, but was not affected after 6 months of exposure. The content of cholesterol and triglycerides in aorta wall, heart and liver was unchanged, although the content of cholesterol was decreased in adrenals of rats exposed for 3 months at concentration of 0.16 mg Cd/m3. Inhalation of cadmium oxide brought about the marked increase of Cd content in lung and kidney of rats exposed at all concentrations an increase of Cd blood level in rats exposed at concentrations of 0.16 mg Cd/m3 and 1.0 mg Cd/m3 and no increase of Cd content in aorta wall.

The measurements of air pollutions in the rolling mill of non-ferrous metals aimed at the evaluation of occupational exposure to nickel and other metals (Cu, Zn, Mn, Mg) used during the production of nickel alloys. It was found that nickel fumes and dusts concentration can be the only hazardous factor for the workers' health. The majority (ca 85%) of the crew of 28 workers is exposed to the nickel concentration in air exceeding 0.05 mg/m3. Smelters (8 persons) at the stand of 97-99% nickel smelting are at the highest risk of the loss of health; average exposure of this group during 8 hours' shift may surpass 2 mg Ni/m3. Mean concentration in air of the fumes and dusts of copper, zinc, manganese and magnesium do not make a hygienic problem.

By stationary measurements the levels of cadmium oxide aerosols concentrations in air at particular workplaces related to cadmium production at non-ferrous metals mill have been determined. High concentrations of that compound have been found at such technological operations as unloading of cadmium-bearing raw materials, batching of cadmium sponge in the induction furnace and casting of fused cadmium into moulds. With the personal dosimetry technique, concentrations of that compound in the workers' breathing zone have been determined. Those were within 0.16-1.84 mg/m3, so--above the TLV values. However, those concentrations do not necessarily reflect the occupational exposure magnitude, as the workers had respirators.

Within the studies, three methodological versions of the determination of VI chromium with diphenylcarbazide have been evaluated. The versions differed primarily by the technique of elution (acid, alkaline) of the chromium sample from the filter. As optimum conditions for determining Cr VI in the presence of Cr III and Fe III, the parameters adopted by Carelli have been determined, some modifications being made consisting in improving and simplifying the analytical procedures, as well as making them more precise, and in the use of available materials.

Results of evaluation of occupational exposure carried on by individual dosimetry and stationary measurements were compared. The former method yielded higher values for airborne cadmium concentrations. The investigations exhibited high cadmium oxide dust concentrations at most workplaces within the alkaline accumulator plant. Time-weighted average (per 8 h) concentrations of this compound in the workers' breathing zone ranged between 0.040-1.5 mg/m3, 85% of the obtained results exceeding the TLV value (0.1 mg Cd/m3).

Using various methods for determination of welding fumes components and taking into account a simultaneous determination of soluble compounds of chromium III and IV, hygienic evaluation in two working places employing different systems of MMA/SS welding, TIG/SS welding and padding was carried out. As it is indicated by the results, proper hygienic evaluation of working conditions is possible owing to the measurements of individual exposure of workers in the breathing zone, allowing for determination of chromium manganese, nickel, and, while applying low-hydrogen electrodes, also fluorides, in every test.

Evaluated in the paper is welders' exposure to fumes resulting from welding of nonalloyed and low-alloyed steel, whether pure or coated with protective layers, using two most popular welding techniques for those types of steel, i.e. metal active gas welding (MAG) and manual welding with covered electrode (MMA). Due to different chemical composition of fumes at particular workstations, the proper hygienic evaluation was based on measurements of individual concentrations of fumes in workers' breathing zone. A considerable contribution of the combined exposure was yielded by such fume constituents as manganese, ferrum and zinc (welding of steel coated with zinc protective layers), also chromium (welding of low- and -highalloyed steel), as well as copper (metal gas welding). The highest combined exposure (10-fold allowable value) was that of welders of steel coated with the zinc layer, using the metal active gas welding.

An analytical procedure for simultaneous determination of soluble and insoluble Cr III and Cr VI compounds in welding fumes has been proposed. In the welding fume samples collected on a membrane filter, total chromium was determined with atomic absorption spectrophotometry (AAS). Glass filters with collected samples were divided into two parts. In one part of the sample, soluble and insoluble chromium was determined by means of AAS. The separation of soluble chromium III and VI was carried out on diphenylcarbazide resin. In the second part of the sample total chromium VI was determined by means of the colorimetric method with s-diphenylcarbazide. The difference in the results of these determinations allowed the calculation of the content of total Cr III, Cr III insolub. and Cr VI insolub. The results of determining chromium compounds in welding fumes samples collected in the welder's breathing zone and in experimental chambers are also presented in this paper. The content of total chromium in the fumes determined by AAS (from a membrane filtr) and that calculated from the sum of soluble and insoluble chromium (from a glass filter) were concordant and within the limits of the admissible error for the method. Total chromium content in welding fume samples collected individually was found to range from 2.4-4.2%. The percentage of particular chromium compounds as compared to total chromium (100%) amounted: total Cr III--34%, total Cr VI--66%, soluble chromium--66% and in this Cr III--20% and Cr VI--43%, insoluble chromium--34% and in this: Cr III--14% and Cr VI--20%.