Occupational exposure cobalt

Occupational exposure to dust of cemented carbide that contains more than 2% cobalt must be controlled so that employees are not exposed at a concentration greater than 0.1 mg cobalt/m air, determined as a TWA concentration for up to a 10-h workshift in a 40-h workweek. 

Occupational exposure to cobalt dust has been associated with cardiomyopathy characterized by functional effects on the ventricles and enlargement of the heart. ... 

Cobalt is found in metal alloys that (1) are very hard, (2) have high melting points, and (3) are resistant to oxidation. Occupational exposure occurs during production and machining of these metal alloys and can lead to interstitial lung disease. " Cardiomyopathy and renal failure are symptomatic of acute Co exposure this was exemplified by an incidence of mass population exposure to Co when beer contaminated witli the metal was consumed. Quantification of urinary Co is an effective means of identifying individuals with excessive exposure. 

The human health and environmental issues associated with nickel-cadmium batteries arise mainly from the ultimate disposal of the spent batteries. In general, occupational exposures to and manufacturing wastes and emissions from nickel, cadmium, cobalt and other materials in NiCd battery production are well regulated and controlled. There is virtually no danger of nickel or cadmium exposure during normal use of NiCd batteries. Even when NiCd batteries are disposed of in landfills, there is little danger of risk or exposure, at least in the short to mid-term, to nickel or cadmium from the battery s electrodes since they are always encased in at least two layers of steel or plastic or both. 

NIOSH (National Institute of Occupational and Health) (1982) Occupational Hazard Assessment Criteria for Controlling Occupational Exposure to Cobalt DHHA (NIOSH) Publication No. 82-107. US Printing Office, Washington DC. 

Raeen E, Mikkelsen S, Altman DG, Christensen JM and Groth S (1988) Health eflfcts due to occupational exposure to cobalt blue dye amongplate painters in a porcelain factory in Denmark. Scand J Work Environ Health 14 378-384. 

Taylor A and Hawkins L (1987) Effects of Occupational Exposure to Cobalt. In Proceedings, Second Nordic Symposium on Trace Elements, Odense. WHO, Copenhagen. 

Chronic fibrotic occupational lung diseases include asbestosis (see p 121), silicosis, coal workers pneumoconiosis, and a few other less common fibrotic lung diseases associated with occupational exposures to such substances as beryllium and hard metal (cobalt-tungsten carbide). These conditions occur after years of exposure and with long latency, although patients may present for evaluation after an acute exposure. Referral for follow-up surveillance is appropriate if exposure is anticipated to be long term. 

Alopecia from thallium is no longer an occupational problem. Cases of accidental discoloration of hair (copper, cobalt, and silver) and nails (mercury, lead, silver and chromium) by occupational exposure are nowadays rarely seen at outpatient clinics. Green hair from copper exposure is mainly non-occupational. 

Water Chemistry of Nuclear Reactor Systems, Bournemouth, UK, 1989, Vol. 1, p. 43-47 Hecht, G. Occupational exposures in LWR plants built by Siemens/KWU including service. Paper presented at the Internat. Workshop on New Developments in Occupational Dose Control and ALARA Implementation at Nuclear Power Plants and Similar Facilities. Brookhaven National Laboratory, Upton, N. Y, 1989 Marchl, T., Riess, R. Reducing the cobalt inventory in Siemens PWRs. Paper presented at the EPRI Radiation Field Control Seminar, Seattle, Wash., USA, 1993 Ocken, H. Radiation control to improve nuclear power plant availability. Proc. Intemat. Conf Nuclear Power Plant Aging, Availabilty Factor and Reliability Analysis, San Diego, Calif, 1985, p. 593-600... 

The exposure level estabUshed by NIOSH for the workplace is 0.1 mg/m (42). ACGIH has recommended a TLV of 0.05 mg/m for cobalt. At the ACGIH worker exposure levels it has been suggested that occupational health problems would not occur (41). 

Toxicology. Cobalt causes skin irritation, allergic contact dermatitis, and occupational asthma interstitial pulmonary fibrosis is associated with exposure to hard metal dust (tungsten and cobalt). 

In the occupational setting, exposure to cobalt alone occurs primarily in the production of cobalt powders. With other industrial exposures, such as hard metal exposure, additional... 

Pellet F, Perdrix A, Vincent M and Mallion JM (1984) Biological determination of urinary cobalt. Significance in occupational medicine in the monitoring of exposures to sintered metallic carbides. Arch Mai Prof Med Trav Secur Soc 45 81-85. Perdrix A, Pellet F, Vincent M, De Gaudemaris R and Mallion JM (1983) Cobalt and sintered metal carbides. Value of the determination of cobalt as a tracer for exposure to hard metals. Toxicol Fur Res 5 233-240. 

Toxicology Exposure is by inhalation. Cobalt causes skin allergies and irritation, and its dust causes occupational asthma. The lARC decided that cobalt metal powder and cobaltous oxide are A3 confirmed carcinogenics in animals, and they are possible human carcinogens [20]. 

Construction workers risk occupational contact dermatitis from exposure to irritants, chromate, cobalt, rubber and epoxy. Nickel allergy, however, is not often discussed in relation to construction work (Coenraads et al. 1984). In construction workers it is often found together with allergy to chromate and/or cobalt, and nickel in cement has been proposed as a cause. However, nickel in cement exists mainly as insoluble salts (Wahlberg et al. 1977 Goh et al. 1986). 

Three common contact allergens diagnosed by standard patch testing - chromium, cobalt, and nickel - head every list of metal contact sensitivity (Chaps. 66-68). Concerning some of the metals reviewed below, cases of occupational contact dermatitis are rarely seen today or are at least not reported. The reason is probably due to extensive preventive measures, including reduced exposure and automation (Chap. 52). However, even if a contact allergy is acquired non-occupationally, there is always a risk of relapses at renewed exposure in an occupational setting. 

Linnainmaa M (1995) Control of exposure to cobalt during grinding of hard metal blades. Appl Occup Environ Hyg 10 692-697... 

Linnainmaa M, Kiilunen M (1997) Urinary cobalt as a measure of exposure in the wet sharpening of hard metal and stellite blades. Int Arch Occup Environ Health 69 193-200... 

Contact dermatitis in army personnel can also be the result of exposures not directly related to the soldiers occupations or working environments. Such was the case with the increased nickel/cobalt sensitization among young Swedish men doing compulsory military service - a significantly higher proportion of positive reactions to nickel and/or cobalt in the 152 men with pierced earlobes (7.9%) was observed than in the 368 (2.7%) whose earlobes were not pierced (Meijer et al. 

Shena D, Rosina P, Chieregato C, Colombari R (1995) Lymphomatoid-like contact dermatitis from cobalt naphtenate. Contact Dermatitis 33 197-198 Tarvainen K, Jolanki R, Forsman-Gronholm L, Est-lander T, Pfaffli P, Juntunen J, Kanerva L (1993) Exposure, skin protection and occupational skin diseases in the glass-fibre-reinforced plastics industry. Contact Dermatitis 29 119-127... 

Occupational cobalt poisoning is caused primarily by inhalation of dust. Prolonged exposure to cobalt powder may produce aUergic sensitization and chronic bronchitis. Because of that a TLV (Threshold limit Value) of 0.1 mg/m is prescribed for cobalt powder. 

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