Chromium(VI) compounds – as Cr(VI).Documentation of proposed values of occupational exposure limits (OELs)

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Chromium(VI) compounds – as Cr(VI).Documentation of proposed values of occupational exposure limits (OELs)

Journal Title: Podstawy i Metody Oceny Środowiska Pracy - Year 2016, Vol 32, Issue 2

Abstract

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/m[sup]3[/sup], 1–6 for an exposure level of 10 μg/m[sup]3[/sup], 0.5–3 for and exposure of 5 μg/m[sup]3[/sup] and 0.1–0.6 for an exposure level of 1 μg/m. 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/m[sup]3[/sup].The Expert Group for Chemical Agents has recommended for chromium (VI) compounds – calculated as Cr(VI) MAC value of 0.01 mg Cr (VI)/m[sup]3[/sup] while the number of additional cases of lung cancer will be 1 ÷ 6 per 1000 people employed in these conditions for entire working life.

Authors and Affiliations

JOLANTA SKOWROŃ, KATARZYNA KONIECZKO

Keywords

związki chromu(VI) rakotwórczość ocena ryzyka wartość NDS chromium(VI) compounds carcinogenicity Risk Assessment MAK

EP ID EP81639
DOI -
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