Occupational exposure to metal

Gorell JM, Johnson CC, Rybicki BA, et al. 1997. Occupational exposures to metals as risk factors for Parkinson s disease. Am Acad Neurol 48 1-9. 

A third historical strand that has helped to create modern toxicology consists of the labors of occupational physicians. Some of the earliest treatises on toxicology were written by physicians who had observed or collected information on the hazards of various jobs. The man some have called the father of the field of occupational medicine was Bernardino Ramazzini, an Italian physician whose text De Moribus Artificum Diatriba (1700) contributed enormously to our understanding of how occupational exposure to metals such as lead and mercury could be harmful to workers. Ramazzini also recognized that it was important to consider the possibility that some poisons could slowly build up in the body and that their adverse effects do not make themselves apparent for a long time after exposure begins. 

Respiratory System. Occupational exposure to metals in the form of metal dust makes the respiratory system a likely target. Acute exposure may cause irritations and... 

Hair has been used in the biomonitoring of various elements, for example, arsenic, thallium, and zinc, and has been used in the monitoring of drugs and biological substances. The level of mercury in hair is widely used as a biological indicator for exposure to methyl mercury (MeHg). In addition, hair samples have been utilized to evaluate environmental exposure to pollutants such as lead, and occupational exposures to metals such as nickel and chromium. However, the ATSDR has stated ... 

S. Satarug, J. R. Baker, P. E. B. Reilly, M. R. Moore and D. J. Williams, Cadmium Levels in the Lung, Liver, Kidney Cortex, and Urine Samples from Australians without Occupational Exposure to Metals, Archives of Environmental Health, 57(1), 69-77 (2002). 

There is inconclusive evidence that occupational exposure to metallic mercury and to organic and inorganic mercury compounds, primarily through inhalation, causes structural and numerical chromosome aberrations in human lymphocytes. In one study, significant increases in the frequency of acentric fragments (chromosome breaks) occurred in 4 workers exposed to high concentrations of metallic mercury and in 18 workers exposed to a mixture of mercuric chloride, methylmercuric chloride,... 

Chronic-Duration Exposure and Cancer. Occupational exposure to metallic mercury vapors has been reported to result in adverse cardiovascular, gastrointestinal, renal, ocular, immunological, and reproductive health effects (Barregard et al. 1988, 1990 Bencko et al. 1990 Bidstrup et al. 1951 Buchet et al. 1980 Cardenas et al. 1993 Cordier et al. 1991 Danziger and Possick 1973 Ehrenberg et al. 1991 ... 

Reproductive Toxicity. Occupational exposure to metallic mercury has not been shown to result in statistically significant effects on male fertility (Alcser et al. 1989 Lauwerys et al. 1985). However, an increase in the rate of spontaneous abortions may occur (Cordier et al. 1991). A spontaneous abortion occurred in a female after ingesting an acute dose of mercuric chloride (Afonso and de Alvarez 1960). There were no studies available on dermal exposure to metallic, inorganic, or organic mercury. 

Developmental Toxicity. Occupational exposure to metallic mercury in males did not result in statistically significant effects on malformations or the number of children bom (Alcser et al. 1989 Lauwerys et al. 1985). The results from an inhalation developmental rat study (Baranski and Szymczyk 1973) suggest that metallic mercury vapors may cause a higher incidence of fetal malformations, resorptions, and deaths. Dermal studies on metallic mercury in humans and animals were not available. Additional well-conducted inhalation and dermal studies on metallic mercury in animals are needed to evaluate the potential for adverse developmental effects to humans from mercury. 

Langauer-Lewowicka H, Kazibutowska Z. 1989. Multimodality evoked potentials in occupational exposure to metallic mercury vapour. Pol J Occup Med 2(2) 192-199. 

Sikorski R, Juszkiewicz T, Paszkowski T, et al. 1987. Women in dental surgeries Reproductive hazards in occupational exposure to metallic mercury. Int Arch Occup Environ Health 59 551-557. 

Gait R, Maginnis C, Lewis S, et al. Occupational exposure to metals and solvents and the risk of motor neuron disease. A case-control study. Neuroepidemiology 2003 22 353-6. 

In subjects with intense and enduring occupational exposure to metallic mercury vapour, or with a high consumption of fish from heavily mercury-polluted waters, the levels in brain may attain the mg/kg level (cf. Swedish Expert group on Methylmercury in Fish, 1971 Berlin, 1986 Clarkson et al., 1988a WHO. 1990). Considerably elevated mercury levels in brain have been found in occupationally exposed or intoxicated subjects still many years after end of exposure (Kosta et al.. 1975 Hargreaves et al.. 1988 Nylander and Weiner, 1991). 

In contrast to these findings Shah et al. (1996) reported that HE in metalworkers carries a poor prognosis, with most workers remaining symptomatic even if they no longer had occupational exposure to metals or oils. Of 51 patients, 82% still had HE. 

Photo contact dermatitis resulting from occupational exposure to metals and ultraviolet (UV) light is rarely reported and may be overlooked. Chromium dermatitis and light are sometimes related (Wahlberg and Wennersten 1977). 

The most significant occupational exposures to zinc would occur during the smelting and refining of zinc ore. The standards for occupational exposure have been estabUshed at a level to prevent the onset of metal fume fever. This temporary condition is caused by excessive exposure to freshly formed fumes of zinc oxide and results in flulike symptoms of fever, chills, headache, muscle pain, nausea and vomiting. 

World Healdi Organization Recommended Healdi-Based Limits in Occupational Exposure to Heavy Metals, Report of a WHO Study Group, WHO, Geneva, Switzerland, 1980. 

Workers involved in the manufacture or use of trichloroethylene as a metal degreaser or general solvent may constitute a group at risk because of the potential for occupational exposure. Occupational exposure to trichloroethylene may also occur during its use as a chemical intermediate in the production of polyvinyl chloride (McNeill 1979). 

Shipman AJ, Whim BP. 1980. Occupational exposure to trichloroethylene in metal cleaning processes and to tetrachloroethylene in the drycleaning industry in the U K. Ann Occup Hyg 23 197-204. 

Results from a recent study showed a marginally significant association of Parkinson s disease with more than 20 years of occupational exposure to lead (Gorell et al. 1997) when the analysis included more than 20 years of combined exposure to lead and iron, the association greatly increased, with the odds ratios exceeding that for exposure to one of the metals alone. 

Occupational exposure to nickel may occur by dermal contact or by inhalation of aerosols, dusts, fumes, or mists containing nickel. Dermal contact may also occur with nickel solutions, such as those used in electroplating, nickel salts, and nickel metal or alloys. Nickel-containing dust may be ingested where poor work practices exist or poor personal hygiene is practiced. A National Occupational Exposure Survey (NOES) conducted by NIOSH from 1981 to 1983 estimates that 727,240 workers are potentially exposed to some form of nickel metal, alloys, salts, or inorganic nickel compounds in the United States (NIOSH 1990). The form of nickel these workers were probably exposed to and the level of exposure for different industries and operations were reviewed by Warner (1984) and lARC (1990). 

Angerer J, Lehnert G. 1990. Occupational chronic exposure to metals. II Nickel exposure of stainless steel welders—biological monitoring. Int Arch Occup Environ Health 62 7-10. 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), approximately 14 000 workers in the United States were potentially exposed to catechol (see General Remarks). Occupational exposures to catechol may occur in its production, in the production of insecticides, perfumes and drugs, in metal-plating shops and in coalprocessing. 

Renal Effects. Occupational exposure to silver metal dust has been associated with increased excretion of a particular renal enzyme (N-acetyl-p-D glucosaminidase), and with decreased creatinine clearance (Rosenman et al. 1987). Both of these effects are diagnostic of marginally impaired renal function. However, the workers in this study were also exposed to cadmium, which was detected in the urine of 5 of the 27 workers studied. Cadmium is known to be nephrotoxic differentiation of the effects of the two metals in the kidney is not possible with the data presented. Therefore, no conclusion can be drawn regarding renal effects of silver based on this study. 

As shown in Table 5-4, the NHANES median values observed for the four metals in the U.S. population correspond, on the average, to about 4% of the BEIs, whereas the 95th percentile values reach up to over 30% of the BEI. Mercury is a special case because occupational exposures to mercury... 

---