This article shows results of exposure to noise in the frequency range 10  ÷ 40 kHz at chosen workstations with ultrasonic welding machines. This paper presents limitation examples of ultrasonic noise emission through the use of technical ways in the cases of two workstations. Ultrasonic noise emission at workstations was reduced with casing of one welding machine and sealing case of the other welding machine. Exposure of workers to ultrasonic noise at welding workstations decreased at the same time.

Hexavalent chromium compounds are oxidation states in which chromium occurs. Occupational exposure to chromium (VI) compounds may occur in chromate-producing industry, production of ferrochromium alloys and chromium metal, production and welding of stainless steels, metal finishing processes (chromium plating), and manufacturing and using chromium chemicals. These latter include corrosion inhibitors (strontium, calcium, zinc and barium chromates); pigments in paints and metal primers (lead and zinc chromates and molybdenum orange); wood preservatives (sodium and potassium chromates and chromium trioxide); dye mordants, catalyst and leather tanning (ammonium, sodium and potassium chromate). Occupational exposure can be to different hexavalent compounds in different industries and in some industries exposure can be to both trivalent and hexavalent compounds.
In Poland in 2005–2012, potassium dichromate (VI) was the most commonly used compound according to information sent to the Central Registry conducted by the IMP in Łódź, about exposure on substances, preparations, agents or carcinogenic or mutagenic technological processes. Recently this compound was reported annually by about 400 enterprises and there were more than 4000 people exposed. The vast majority of reported workplaces where chromium (VI) compounds occur were the laboratory positions (in 2011–2012 more than 75%). Over 10% of workplaces were associated with electroplating or etching the surface and about 4% with welders.
In 2011, 11 factories reported to the Register that they exceeded the MAK value (NDS) for chromate (VI) and dichromates (VI). High concentrations were reported at 12 workplaces where 60 people were exposed. At 7 workplaces related to plating, 17 people were employed and chromium concentrations ranged from 0.11 to 0.96 mg/m3, at 2 welding workplaces (12 people were exposed) concentrations were 0.22 and 0.27 mg/m3, 14 workers were exposed during the production of paints containing chrome pigments, which chromium concentration was 0.21 mg/m3, 12 people were employed in the sewage treatment plant where chromium concentration was 0.21 mg/m3, and 1 person worked in a laboratory where chromium concentration was 0.18 mg/m3. In 2008–2012, there were no high MAK concentrations of chromates (VI) and dichromates (VI) in workplaces under the supervision of the GIS.
The health effects associated with occupational exposure to hexavalent chromium compounds are carcinogenicity (especially lung cancer), sensitisation, renal toxicity and irritancy, and corrosivity of the skin, respiratory and gastrointestinal tract.
The IARC classify chromium (VI) compounds to group 1 carcinogen to humans, as there is sufficient evidence of carcinogenicity of these compounds to humans. Also the EU, EPA and WHO classified chromium (VI) as carcinogenic to humans.
The risk assessment of carcinogenicity is based on a summary of 10 studies. and it has been estimated that 5–28 excess lung cancers will occur in a group of 1000 male workers, followed-up from 20 to 85 years and occupationally exposed to 50 μg/m3 of hexavalent chromium until retirement at age 65. The corresponding number of excess lung cancers has been estimated to be 2–14 for an exposure level of 25 μg/m3, 1–6 for an exposure level of 10μg/m3, 0.5–3 for and exposure of 5μg/m3 and 0.1–0.6 for an exposure level of 1μg/m3. Proposed in various studies estimations of the risk of carcinogenic chromium (VI) does not distinguish between very poor and insoluble compounds of chromium (VI). However, the available evidence, although incomplete, clearly suggest that poorly soluble Cr (VI) causes lower risk of lung cancer, although the extent of this limitation cannot be quantified.
In 2004, SCOEL did not establish OEL value for chromium (VI) compounds, but it assessed the risk of lung cancer in workers occupationally exposed to chromium (VI) compounds on the basis of aggregated data. The Advisory Committee of Safety and Health (ACSH) pre-accepted proposal of binding (BOELV) chromium (VI) compounds at the level of 0.025 mg/m3.
The Expert Group for Chemical Agents has recommended for chromium (VI) compounds – calculated as Cr(VI) MAC value of 0.01 mg Cr (VI)/m3 while the number of additional cases of lung cancer will be 1 ÷ 6 per 1000 people employed in these conditions for entire working life.

Tin at room temperature is a soft, silvery metal. In the industry it is used as a component of bearing, brazing and casting alloys and for the preparation of protective coatings, dishes and tin amalgam.
Tin compounds are toxic. The result of exposure to tin can be a non-collagenous pneumoconiosis referred to as the cynics. Tin and its compounds cause skin irritation and chronic conjunctivitis. Tin compounds accumulate in the body. Exposure limit value (NDS) for tin and inorganic compounds is 2 mg/m3.
The aim of this study was to develop a method for determining concentrations of tin and its inorganic compounds in workplace air in the range from 1/10 to 2 NDS values, in accordance with the requirements of Standard No. PN-EN 482:2012E. The developed method replaces the method described in Standard No. PN Z-04229-03:1996.
The method involves collecting tin and its compounds from the air on a membrane filter, filter mineralization with concentrated hydrochloric acid and nitric acid, and determining tin in the solution prepared for analysis with flame atomic absorption spectrometry (AAS). The calibration curve obtained in the concentration range 5.00  120.0 g/ml has a high correlation coefficient (R2 = 1.0000) and corresponds to the concentration range of 0.17  4.17 mg/m3 for a 720-L air sample. The average value of the efficiency factor of mineralization was 1.00.
The developed method for determining tin and its inorganic compounds enables determination of the smallest amount in workplace air at the level of 0.17 mg/m3. The method is accurate, precise and it meets the criteria for procedures for determining chemical agents used to evaluate occupational exposure. The developed method of determining tin and its inorganic compounds has been recorded as an analytical procedure (see appendix).

The pure octabromodiphenyl ether (octaBDE) is a white, inflammable solid with characteristic odor, obtained by bromination of diphenyl ether. Octabromodiphenyl ether belongs to the group of brominated aromatic compounds used as flame retardants. It was most often used in the production of synthetic polymers used in the electric, electronic and car industries. Due to its physicochemical proprieties, octabromodiphenyl ether belongs to the group of so called persistent organic pollutants (POP’s) which production and utilization is banned in European Union since 2004. Occupational exposure may take place mainly in waste incineration plants and during using electric and electronic equipment. The most important toxic effects of octabromodiphenyl ether are functional changes in the liver and thyroid, and changes in the respiratory tract after inhalation. Octabromodiphenyl ether did not show mutagenic or genotoxic properties. Environmental Protection Agency (EPA) classified octabromodiphenyl ether in Class D (group of compounds not classified as a carcinogen for humans)
The aim of this study was to develop and validate a sensitive method for determining octabromodiphenyl ether concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard PN-EN 482:2012.
Studies were performed using gas chromatography (GC). A 7890B Agilent Technologies gas chromatograph equipped with a 5977A mass spectrometry detector (MSD), ZB 5-HT INFERNO (30 m × 0.25 mm × 0.25 µm) capillary analytical column, autosampler and Mass Hunter software was used for chromatographic separations.
The method is based on the adsorption of inhalable fraction of octabromodiphenyl ether on glass fiber filters, desorption with toluene and gas chromatographic-mass detection (GC/MS) analysis of the resulting solution. Extraction efficiency of octabromodiphenyl ether from filters was 95.7%. Samples of octabromodiphenyl ether can be stored in refrigerator for up to 30 days. The use of a ZB 5-HT INFERNO (30 m × 0.25 mm × 0.25 µm) capillary column enabled selective determination of octabromodiphenyl ether in a mixture of polibromineted diphenyl ethers, toluene and other compounds.
This method is linear (r = 0.999) within the investigated working range 1 ÷ 20 µg/ml, which is equivalent to air concentrations from 0.01 to 0.20 mg/m3 for a 200-L air sample. Limit of quantification (LOQ) is 0.365 μg/ml.
The analytical method described in this paper enables selective determination of octabromodiphenyl ethers in workplace air in the presence of other compounds at concentrations from 0.01 to 0.20 mg/m3 (1/10 ÷ 2 MAC value). The method is precise,  accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard PN-EN 482:2012. This method can be used for assessing occupational exposure to octabromodiphenyl ether and associated risk to workers’ health.
The developed method of determining octabromodiphenyl ether has been recorded as an analytical procedure (see appendix).

Tellurium is used in the industry as an alloying addition (steel, lead alloys, magnesium and cop-per), a catalyst for chemical reactions and as addition to rubber. It is also used for coloring glass and porcelain.
Tellurium is harmful to respiratory tract, eyes and skin. As a result of acute intoxication liver, nervous and cardiovascular systems can be damaged. Chronic exposure to tellurium causes drowsi-ness, headache, gastrointestinal disturbances and allergic reactions of the skin.
Exposure limit values for tellurium and its compounds in workplace air are NDS 0.01 mg/m3  and NDSCh 0.03 mg/m3.
The aim of this study was to develop a method for determining concentrations of tellurium and its compounds in workplace air in accordance with the requirements of Standard No. EN 482:2012E.
The method involves collecting tellurium and its compounds from the air on a membrane filter, filter mineralization with concentrated nitric acid and determining tellurium in the solution pre-pared for analysis with atomic absorption spectrometry with electrothermal atomization (ET-AAS). The calibration curve of tellurium in the concentration range 10.00  100.00 g/l has a correlation coefficient R2 = 0.9998, and corresponds to the concentration range of 0.001  0.01 mg/m3 for a 720-L air sample. The average value of the efficiency factor of mineralization was 1.00.
The developed method for determining tellurium and its compounds enables determination of the smallest amount in workplace air at the level of 0.001 mg/m3. The method is accurate, precise and it meets the requirements for procedures for determining factors used to determine occupational exposure.
The developed method of determining tellurium and its compounds has been recorded as an analyt-ical procedure (see appendix).