Vanadium exposure

Since vanadium is a natural element in the earth, we all have a small amounts in our bodies. There are some tests to show whether you have been exposed to larger than normal amounts of vanadium. Vanadium can be measured in the urine and blood. People exposed to larger than normal amounts will show larger than normal amounts in their urine and blood for a few days. Some workers who have been exposed to large amounts of vanadium may have a green color on the tongue. None of these tests can tell if you will become sick from the vanadium but they are specific for vanadium exposure. For more information on ways to tell whether you have been exposed to vanadium see Chapters 2 and 6. 

Volunteers exposed acutely had no neurological complaints (Zenz and Berg 1967). Most workers exposed to vanadium dusts did not report major adverse neurological signs (Sjoeberg 1956 Vintinner et al. 1955). However, some workers complained of dizziness, depression, headache, or tremors of the fingers and arms (Levy et al. 1984 Vintinner et al. 1955), which may or may not have been specifically due to vanadium exposure. 

Several biomarkers of exposure have been identified for vanadium but none of them can be used to quantitatively determine exposure levels. Vanadium is found in the urine of exposed workers. This measurement is specific for vanadium. Some vanadium workers develop a characteristic green tongue, as a result of direct accumulation of the vanadium dusts on the tongue (Lewis 1959). One report from the 1950s states that vanadium exposure was associated with decreased cystine content in the fingernails of vanadium workers (Mountain 1955). However, alterations in cystine levels can also be associated with dietary changes and with other disease states, so this is not specific for vanadium exposure. No other commonly measured cellular changes have been identified with vanadium exposure. 

Developmental Toxicity. No human data were located on developmental effects of vanadium exposure by any exposure route. Since vanadium is poorly absorbed by the gastrointestinal tract (Conklin et al. 1982 Roschin et al. 1980) or skin (WHO 1988), exposure by these routes would be unlikely to result in a significant internal dose. Animal toxicokinetic studies do not indicate that the fetus accumulates vanadium. The lack of developmental studies decreases the confidence in the MRL... 

Immunotoxicity. Effects on lymphoid tissue or peripheral lymphocytes have not been noted in the occupational studies in humans (Sjoeberg 1950) or in the animal studies (Sharma et al. 1981 Sjoeberg 1950). However, this system may still be affected since vanadium has been shown to have adverse effects on macrophages in vivo and in vitro (Cohen et al. 1986). Few workers have shown allergic responses or contact dermatitis from vanadium exposure (Sjoeberg 1950), so further work in this area is probably not critical. 

A decreased level of cystine (or cysteine) in hair and fingernails has been historically linked to vanadium exposure and suggested as a monitor of exposure (Mountain 1955). Accurate and precise methods exist for measuring these amino acids, but their depletion in hair and fingernails is not specific for vanadium exposure. More recent research did not indicate a correlation between cystine (or cysteine) depletion and vanadium exposure. There does not appear to be a need for additional research on this topic. 

Donaldson J, Hemming R, LaBella F. 1985. Vanadium exposure enhances lipid peroxidation in the kidney of rats and mice. Can J Physiol Pharmacol 63 196-199. 

Lewis CE. 1959. The biological effects of vanadium. II. The signs and symptoms of occupational vanadium exposure. AMAArch Ind Health 19 497-503. 

Kasibhatia U and Rai V (1993) Haematological changes following vanadium exposure. Geobios 20 85-95. 

The main vanadium exposure risks at the workplace occur during the processes of vanadium extraction and preparation from the minerals and to a greater extent during cleaning and repair of petrol containers and oil-fired boilers. For the biological monitoring... 

A green-black discoloured tongue can be regarded as an indicator of vanadium exposure. but may be absent even with long term 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. 

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). 

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). 

Cobalt in Driers for Paints, Inks, and Varnishes. The cobalt soaps, eg, the oleate, naphthenate, resinate, Hnoleate, ethyUiexanoate, synthetic tertiary neodecanoate, and tall oils, are used to accelerate the natural drying process of unsaturated oils such as linseed oil and soybean oil. These oils are esters of unsaturated fatty acids and contain acids such as oleic, linoleic, and eleostearic. On exposure to air for several days a film of the acids convert from Hquid to soHd form by oxidative polymeri2ation. The incorporation of oil-soluble cobalt salts effects this drying process in hours instead of days. Soaps of manganese, lead, cerium, and vanadium are also used as driers, but none are as effective as cobalt (see Drying). 

Vanadium (metal) [7440-62-2] M 50.9, m 1910°, d 6.0. Cleaned by rapid exposure consecutively to HNO3, HCl, HF, de-ionised water and reagent grade acetone, then dried in a vacuum desiccator. 

The ash deposits resulting from the combustion of solid and oil fuels often contain appreciable quantities of other corrodants in addition to vanadium pentoxide. One of the more important of these is sodium sulphate, and the effects of this constituent in producing sulphur attack have been mentioned. The contents of sodium sulphate and vanadium pentoxide present in fuel oil ash can vary markedly and the relative merits of different materials depend to a great extent upon the proportions of these constituents. Exposure of heat-resisting alloys of varying nickel, chromium and iron contents to ash deposition in the super-heater zones of oil-fired boilers indicated a behaviour pattern depending on the composition of the alloy and of the ash... 

With the exception of iron(II) and uranium(IV), the reduced solutions are extremely unstable and readily re-oxidise upon exposure to air. They are best stabilised in a five-fold excess of a solution of 150g of ammonium iron(III) sulphate and 150 mL of concentrated sulphuric acid per litre [approximately 0.3M with respect to iron] contained in the filter flask. The iron(II) formed is then titrated with a standard solution of a suitable oxidising agent. Titanium and chromium are completely oxidised and produce an equivalent amount of iron(II) sulphate molybdenum is re-oxidised to the Mo(V) (red) stage, which is fairly stable in air, and complete oxidation is effected by the permanganate, but the net result is the same, viz. Mo(III)- Mo(VI) vanadium is re-oxidised to the V(IV), condition, which is stable in air, and the final oxidation is completed by slow titration with potassium permanganate solution or with cerium(IV) sulphate solution. 

Exposure of s.o. samples to NH3-NO at 623 K, caused a slight reduction of V to V v, whereas exposure to NO-NH3-O2, did not affect the vanadium oxidation state. Exposure of reduced samples (CO at 623 K) to NH3-NO caused slight oxidation, whereas exposure to NO-NH3-O2 oxidized all V . ... 

Fig. 5 Infrared spectra of 0.03 ML vanadium deposited on silica as a function of CO exposure. Preparation and measurements were done at 90 K...

Brunnock et al. [67] have also determined beach pollutants. They showed that weathered crude oil, crude oil sludge, and fuel oil can be differentiated by the n-paraffin profile as shown by gas chromatography, wax content, wax melting point, and asphaltene content. The effects of weathering at sea on crude oil were studied parameters unaffected by evaporation and exposure are the contents of vanadium, nickel, and n-paraffins. The scheme developed for the identification of certain weathered crude oils includes the determination of these constituents, together with the sulfur content of the sample. 

Strontium, barium, manganese, copper, molybdenum, and nickel are elements of strong accumulation in plant species of African Savanna ecosystems, in spite of different content in soils and soil-forming rocks. The Cb values are >1. The other elements, like beryllium, zirconium, titanium and vanadium, are less taken up by plants and their Cb values are less than 0.5. These refer to various exposure pathways to both microbes and plants as links in biogeochemical food webs. 

One of the most important requirements that must be met is the membrane s ability to prevent excessive transfer of water from one half cell to the other. The preferential transfer of water can be a problem in the vanadium battery as one half-cell (the negative half cell in the case of cation exchange membranes) is flooded and becomes diluted, while the other becomes more concentrated, adversely affecting the overall operation of the cell. Most of the membranes show good initial water transfer properties, but their performance deteriorates with exposure to the vanadium solutions. Sukkar et al. ° evaluated various polyelectrolytes to determine whether they could improve the selectivity and stability of the membranes in the vanadium redox cell solutions. Both the cationic and anionic polyelectrolytes evaluated improved the water transfer properties of the membranes, although upon extended exposure to the vanadium electrolyte the modified membranes did not maintain their improved water transfer properties. The solvent based Nuosperse 657 modified membrane displayed exceptional properties initially but also failed to maintain its performance with extended exposure to the vanadium solutions. 

Todaro A, Bronsato R, Buratti M, et al. 1991. Acute exposure to vanadium-containing dusts the health effects and biological monitoring in a group of workers employed in boiler maintenance. Med Lav 82(2) 142-147. 

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