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Under the rules of chemical safety assessment, derived-no-effect-levels (DNELs) should be established for all registration-subjected substances, which are put on the market in quantities of 10 tonnes and more per year. DNELs represent exposure levels above which humans should not be exposed to. The purpose of DNELs is to serve as a reference value for determining adequate control of exposure for specific scenarios. Since a considerable number of exposure scenarios may comprise occupational inhalation exposure, DNELs may be wrongly understood as a kind of Occupational Exposure Limit, therefore, the issue of their integration into the national legislation on occupational safety and health (OSH) acquires crucial importance. In this paper, procedures for establishing DNELs and occupational exposure limits in the European Union (OEL) and Poland (MAC) are compared. The role of MAC values in Polish occupational safety and health is also discussed. In occupational inhalation exposure, DNELs may serve as a kind of guidelines and tentative criteria for risk characterization/assessment of substances for which sound scientific MAC values have not yet been determined, however, this requires formal introduction of DNELs into Polish OSH legislation.

The objective of the study was to determine occupational exposure of municipal transport bus drovers to selected aldehydes: formaldehyde, acetaldehyde and acrolein. Ten drivers serving 5 bus lines were selected for the study. Air samples were collected in the driver's breathing zone and in bus cabins. The test air (about 10 l) was drawn through columns filled with silicagel coated by dinitrophenylhydrazine (DNPH). The products of DNPH reaction with aldehydes were extracted with acetonitrile and analyzed by HPLC with a spectrophotometric detector (lambda = 360 nm). The analytical procedure enabled to determine the selected aldehydes in the concentration range equivalent to 0.1-2.0 of the Polish maximum allowable concentrations (MAC). In the quantitative analysis, the concentrations of selected aldehydes were found to be much lower than MAC values, regardless of the bus type. The concentrations of formaldehyde and acrolein ranged from 0.025 to 0.090 mg/m3 and from 0.010 to 0.035 mg/m3, respectively. In all samples, acetaldehyde concentrations were well below the limit of detection of the analytical method. The combined exposure to aldehydes was also below the limit value for mixtures.

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.

The goal of the assessment of exposure to chemicals is to demonstrate the compliance with occupational exposure limit (OEL). There are numerous publications on recommended air sampling strategies for compliance measurements of time weighted average (TWA) concentrations of chemicals but no clear and unambiguous guidelines for measurements and interpretation of ceiling concentrations can be found. Furthermore, definitions and interpretation of ceiling values in different countries may differ considerably. Systems of establishing ceiling limit values, their definitions and interpretation in Germany, the USA (OSHA, ACGIH and NIOSH), the UK and Poland have been reviewed. In most countries of the European Union and in the USA, continuous monitoring using either self contained instruments, multipoint sampling systems or multiplexed sensors is considered as being the most appropriate approach. Based on the literature review the following air sampling strategies have been proposed:--for substances with both OEL--Ceiling and OEL-TWA values dual sampling: 8-hour samples for time weighted average concentrations, and in parallel short (5-10 min) samples during the expected highest exposure for ceiling concentrations measurements; for substances with OEL--Ceiling as the only exposure limit (which is preferable); continuous monitoring using direct reading instruments, possibly with an alarm device. If such instruments are not available, short time measurements may be performed at regular (30 min) intervals using direct reading gas analysers or detector tubes.

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.

Exposure of workers employed in the distribution and transportation of liquid fuels is a very complex problem. As a preliminary stage, an analytical procedure for the identification and quantitative determination of liquid fuel components is presented. The composition of different types of gasoline was also analysed. Knowledge about the fuel composition is essential for predicting exposure to hydrocarbons and other unburned compounds amitted from tanks and car engines.

On the basis of an external quality control of sulfur dioxide measurements in the atmospheric air (emission), the preparation of control material, its evaluation and a two-week durability of the material are presented. The results of the control test carried out in autumn 1994 is also discussed.

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.

To evaluate the usefulness of passive reactive dosimeters for the determination of individual exposure to carbon disulphide, field studies in viscose plants in Poland and East Germany have been carried out. Totally, 43 workers have been examined, using active charcoal pipes joined with personal samplers as a reference air sampling method. The results of measurements point to a statistically significant difference between passive dosimeters findings and exposure evaluation by the reference method. The 1.5-2.2 times lower results indicate too little usefulness of passive dosimeters made in East Germany as a quantitative method of evaluating occupational exposure to carbon disulphide in Polish viscose plants.

Basing on literature data on toxic effects of oil mist as well as on the results of epidemiological studies, an airborne concentration of 5 mg/m3 of oil mist was suggested as a safe value and 10 mg/m3--as a limit value MAC. Analytical methods used to determine oil mist in the air were surveyed. The fluorescence method was regarded as the best one for evaluation of occupational exposure within low concentrations. Also the determination of polycyclic aromatic hydrocarbons seems to be advisable at the workstations where cutting fluids are used. A number of recommendations wee given aimed at a decrease in occupational risk at work with oils and oil emulsions used as a cooler.

A gas chromatographic method for determination of methyl acetate, ethyl acetate, propyl acetate, butyl acetate and amyl acetate has been elaborated. The best separation of determined compounds has been achieved on a column containing 10% Carbowax 20 M on Chromosorb W AW DMCS. Air samples are collected by passing the examined air through charcoal tubes and consequent desorption of adsorbed compounds with carbon disulfide. Activated charcoal used in all tests has been found to adsorb 10%, by weight, of acetic acid esters.

The authors discuss methods for applying individual dosimetry in the assessment of occupational exposure to toxic substances. Methods for air sampling using individual pumps and individual passive dosimeters in order to estimate weighted average concentration and momentary concentration for the whole working shifts are presented. Also, the principles of interpreting measuring results are indicated.

State methods for preparation of gas mixtures have many disadvantages. Losses of components due to adsorbtion on the container surface (glass of plastic) are the main problem. Flow--dilution dynamic systems are much more convenient, giving practically unlimited quantities of mixtures of chemical substances with air at fixed concentration. Dynamic methods enable rapid change in concentration of generated mixture and surface adsorbtion does not exist. To produce at stable rate the substance to be diluted with air, microdiffusion, motor driven syringes (or peristaltic pumps) saturated vapours, permeation tubes and pressure cylinders may be employed. Our experience showed that pressure cylinders are the best for preparation of mixtures of gases (i.e. vinyl chloride) with air and peristaltic pumps are the best as the source of vapours for further dilution. The latter method may be employed as well for mixtures of several compounds (i.e. acetic acid esters) with air.

Information concerning exposure to vinyl chloride collected in Occupational Hygiene Departments of Sanitary-Epidemiological Stations were verified. On the basis of the studies performed it was found that about 3700-4000 persons in Poland are occupationally exposed to vinyl chloride; 400 of these workers are employed at the synthesis and polymeryzation of vinyl chloride, and the others at plasticination and processing of polyvinyl chloride. About 200 workers employed in 3 plants of vinyl chloride polymerization and synthesis and about 30 employees of one of the plants processing this compound are exposed to vinyl chloride whose concentration exceeds the hygienic standard accepted in Poland (30 mg/m3).

Literature on biological action of mineral oils used as coolants has been surveyed. The data indicate different biological action depending on the origin of fundamental materials and additives used to improve the functional quality. In industry mineral oils may adversely affect primarily the respiratory system and skin. Both investigations of mineral oil aerosols effects in animals and epidemiological examinations of workers exposed to oil mist urgently call for the reduction of oil concentrations in work environment. The irritating properties of oils and oil emulsions vary with quantitative--qualitative chemical composition of those substances. Carcenogenic effects of oils are due to polycyclic aromatic hydrocarbons.

The paper presents the principles of performing stationary measurements for the assessment of occupational exposure to toxic substances. A classification of work-stands was introduced according to the length of time spent at them. The strategy of measurements was adapted to the type of a given work-stand. The interpretation of measurement results was based on the exposure factors, relevant for a specific work-stand. Also, the principles of air sampling and of the interpretation of the results of the evaluation of instantaneous and threshold concentrations are discussed.

Data on occupational exposure to beta-naphthylamine obtained from Departments of Occupational Hygiene in Sanitary-Epidemiological Stations have been verified. The verification implied that this compound may occur in air only at the production of phenyl-beta-naphthylamine and in few research laboratories where exposure bears no industrial nature. The exposure to beta-naphthylamine at the production of phenyl-beta-naphthylamine was evaluated. The studies demonstrated that beta-naphthylamine occurs in air only at scaling of phenyl-beta-naphthylamine and its concentration does not exceed 0.0024 mg/m3.