Vanadium compounds exposure

Magnesium vanadates, as vanadium compounds in general, are known irritants of the respiratory tract and conjunctiva. The threshold limit value (TLV) for vanadium compounds in air recommended by the National Institute of Occupational Safety and Health is 0.05 mg/m based on a typical 8-h workday and 40-h workweek (7,147). Chronic inhalation can lead to lung diseases such as bronchitis, bronchopneumonia, and lobar pneumonia. These dust-related effects can be avoided by use of individual respirators in areas where exposure is likely. 

Vanadium compounds, including those which may be involved in the production, processing, and use of vanadium and vanadium alloys, are irritants chiefly to the conjuctivae and respiratory tract. Prolonged exposure may lead to pulmonary compHcations. However, responses are acute, never chronic. Toxic effects vary with the vanadium compound involved. For example, LD q (oral) of vanadium pentoxide dust in rats is 23 mg/kg of body weight (24). 

The adopted values for TWAs for airborne vanadium, including oxide and metal dusts of vanadium, is 0.5 mg/m the values for fumes of vanadium compounds is 0.05 mg/m. These limits are for normal 8-h workday and 40-h work-week exposures. The short-term exposure limit (STEL) is 1.5 mg/m for dusts (25). A description of health ha2ards, including symptoms, first aid, and organ involvement, personal protection, and respirator use has beenpubhshed (26). 

Vanadium pentoxide was not mutagenic in SalTtumella strains and did not increase the frequency of micronucleated erythrocytes in mice. In other smdies vanadium compounds have produced clear evidence of aneuploidy in somatic cells after exposure by several different routes. "... 

Most of the toxic effects of vanadium compounds result from local irritation of the eyes and upper respiratory tract rather than systemic toxicity. The only clearly documented effect of exposure to vanadium dust is upper respiratory tract irritation characterized by rhinitis, wheezing, nasal hemorrhage, conjunctivitis, cough, sore throat, and chest pain. Case studies have described die onset of asthma after heavy exposure to vanadium compounds, blit clinical studies to date have not detected an increased prevalence of asthma in workers exposed to vanadium. 

Probably the vanadium compound to which people are most likely to be exposed is vanadium pentoxide, V205. Exposure normally occurs via the respiratory route, and the pulmonary system is the most likely to suffer from vanadium toxicity. Bronchitis and bronchial pneumonia are the most common pathological effects of exposure skin and eye irritation may also occur. Severe exposure can also adversely affect the gastrointestinal tract, kidneys, and nervous system. 

To date, there is limited published material concerning the pharmacokinetics of vanadium compounds in humans. The concentration of vanadium in humans not dosed with the metal is extremely low and at the limits of detection of many of the analytical techniques used. It is not possible to ascertain if the large differences observed in different populations are the result of environmental exposure or experimental variability. Studies using blood have shown vanadium levels of 0.4 to 2.8 pg/L in normal people. The serum contains the largest amount of vanadium with concentration values ranging from 2 to 4 pg/L using atomic absorption spectroscopy [90], The upper limit of vanadium in the urine of normal people was reported to be 22 pg/L, with excretion values averaging below 8 pg/24 h. Vanadium is widely available in nutrition stores for athletes, who believe it to be a nonsteroidal compound that increases muscle mass at a dose of approximately 7 to 10 mg day, without any reports of toxicity [91]. 

NIOSH REL (Vanadium Compounds) CL 0.05 mg(V)/m2/15M SAFETY PROFILE Variable toxicity. Vanadium compounds act chiefly as an irritant to the conjunctiva and respiratory tract. Acute and chronic exposure can give rise to conjunctivitis, rhinitis, reversible irritation of the respiratory tract, and to... 

Musk AW, Tees JG. 1982. Asthma caused by occupational exposure to vanadium compounds. 

Vanadium is mainly absorbed via the respiratory and gastrointestinal routes. The oxidation state of vanadium does not appear to influence absorption (Carson et al.. 1986). In occupational exposure the main route of absorption is by inhalation of dust and fumes containing vanadium or vanadium compounds. 

Gastrointestinal absorption is the major route for nonoccupational exposure. The major source of gastrointestinal intake is diet. Absorption of the quantity introduced with the diet is usually low (<1 percent) (Byrne and Kosta, 1978). Experiments in which rats were given radio-vanadium compounds by mouth showed intestinal absorption of only 0.5% of the amount administered. 

Acute exposure to vanadium compounds causes irritation of the eyes and the upper and lower respiratory tract. Mild effects are characterized by sneezing rhinitis, cough, chest pain and conjunctivitis. These effects seem to be concentration-dependent and usually reversible. Exposure of healthy volunteers to vanadium pentoxide dust (1 mg/m ) produced respiratory irritation and a persistent cough lasting 8 days this occurred after about 12 h. Exposure to a lower concentration (0.2 mg/m ) had the same effect but the induction time for the persistent cough was longer (about 20 h). Concentrations of 0.1 mg/m caused no irritation (Zenz and Berg. 1967). 

Chronic exposure to vanadium may also cause rhinitis, pharyngitis and bronchitis, but the amount of exposure is not conclusive. Evidence of systematic effects in workers exposed to vanadium compounds is sketchy. In most cases, no systematic effects have been reported (Symansky, 1939 Williams, 1952 Lewis, 1959 Zenz et al., 1962 Eisler et al., 1968). Other reports describe only vague or unspecific signs and symptoms such as weakness, ringing in the ears, nausea, vomiting, and headache (Roshchin, 1962). 

Vanadium concentrations in blood, serum or urine are used as a biological indicator of exposure to vanadium. Urine and serum are the specimens with widest application and greatest practicability for monitoring human exposure to vanadium compounds, but urine is preferred as an indicator medium. Blood vanadium appears to be a less sensitive indicator than urinary vanadium, partly because the differences in concentrations are hardly appreciable at low levels of exposure with the analytical methods available (Alessio et al., 1988). 

Lees, R.E.M. (1980). Changes in lung function after exposure to vanadium compounds in fuel oil ash, Brit. J. Ind. Med., 3L 253. 

Vanadium compounds are toxic to varying degrees [9]. They act chiefly as irritants to the conjunctivae and respiratory tract. Prolonged exposure may lead to pulmonary involvement. There is still some controversy as to the effects of industrial exposure on other systems of the body. Responses are acute, never chronic. 

Human Experience Occupational exposure to these catalysts has been reported to cause severe eye, skin and upper respiratory tract irritation. Excessive acute exposure to vanadium compounds may produce coughs, wheezing, difficulty in breathing, chest pains, bronchitis, influenza-like symptoms and possible pneumonia. 

Under unusual circumstances, toxicity may arise from ingestion of excess amounts of minerals. This is uncommon except in the cases of fluorine, molybdenum, selenium, copper, iron, vanadium, and arsenic. Toxicosis may also result from exposure to industrial compounds containing various chemical forms of some of the minerals. Aspects of toxicity of essential elements have been pubhshed (161). 

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