Occupational Exposure To Vanadium-rich Fuel-oil Ash

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US NAVY BOILERMAN and Occupational exposure to vanadium-rich fuel-oil ash

http://www.ehs.cornell.edu/

Article

Acute respiratory symptoms in workers exposed to vanadium-rich fuel-oil ash

Mark A. Woodin, ScD, MS 1 2, Youcheng Liu, MD, ScD, MPH 1, Donna Neuberg, ScD 3, Russ Hauser, MD, ScD, MPH 1, Thomas J. Smith, PhD, MPH 1, David C. Christiani, MD, MPH 1 2 4 *

1Department of Environmental Health (Occupational Health Program), Harvard School of Public Health, Boston, MA 02115

2Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115

3Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115

4Pulmonary and Critical Care Unit, Department of Medicine, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114

email: David C. Christiani (dchris@hohp.harvard.edu)

*Correspondence to David C. Christiani, Harvard School of Public Health, Department of Environmental Health, 665 Huntington Avenue, Boston, MA 02115.

Funded by:

NIEHS; Grant Number: ES05947, ES07069, ES00002

NIOSH; Grant Number: OH02421, CCU109979

Keywords

vanadium; PM10; occupational epidemiology; occupational lung disease; boilermakers; industrial hygiene

Abstract

Background

Occupational exposure to fuel-oil ash, with its high vanadium content, may cause respiratory illness. It is unclear, however, what early acute health effects may occur on the pathway from normal to compromised respiratory function.

Methods

Using a repeated measures design, we studied prospectively 18 boilermakers overhauling an oil-fired boiler and 11 utility worker controls. Subjects completed a respiratory symptom diary five times per day by using a 0-3 scale where 0=symptom not present, 1=mild symptom, 2=moderate symptom, and 3=severe symptom. Daily symptom severity was calculated by using the highest reported score each day for upper and lower respiratory symptoms. Daily symptom frequency was calculated by summing all upper or lower airway symptom reports, then dividing by number of reporting times. Respiratory symptom frequency and severity were analyzed for dose-response relationships with estimated vanadium and PM10 doses to the lung and upper airway by using robust regression.

Results

During the overhaul, 72% of boilermakers reported lower airway symptoms, and 67% reported upper airway symptoms. These percentages were 27 and 36 for controls. Boilermakers had more frequent and more severe upper and lower respiratory symptoms compared to utility workers, and this difference was greatest during interior boiler work. A statistically significant dose-response pattern for frequency and severity of both upper and lower respiratory symptoms was seen with vanadium and PM10 in the three lower exposure quartiles. However, there was a reversal in the dose-response trend in the highest exposure quartile, reflecting a possible healthy worker effect.

Conclusions

Boilermakers experience more frequent and more severe respiratory symptoms than utility workers. This is most statistically significant during boiler work and is associated with increasing dose estimates of lung and nasal vanadium and PM10. Am. J. Ind. Med. 37:353-363, 2000. © 2000 Wiley-Liss, Inc.

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http://www.osha.gov/dts/sltc/methods/inorg...d185/id185.html

Inorganic Methods Evaluation Branch

OSHA Salt Lake Technical Center

Salt Lake City, Utah

1. Introduction

The goal of this method is to provide confirmation for occupational vanadium pentoxide (V2O5) exposures. To achieve that end, the published X-ray diffraction (XRD) approach presented in a NIOSH study (8.1.) for various V compounds was evaluated for applicability. Unlike the NIOSH study, this method focuses on only V2O5. The method was further extended to evaluate the applicability of X-ray fluorescence (XRF) to measure V2O5 exposures, since sample preparation was also compatible with XRF analysis.

The procedure used in the NIOSH XRD study was adapted from the published analytical procedure (8.1.) and techniques (8.2.) that were in print prior to the publication of NIOSH Method 7504 (8.3.). The NIOSH sampling approach collects and analyzes only the respirable fraction because of its toxic effects (8.1.). [Vanadium pentoxide is also toxic by other routes of exposure (8.4.-8.6.)]

Particle size effects on the analysis were investigated during the OSHA validation when the OSHA PEL was for total dust and fume (i.e. Transitional PELs). The respirable particle-size range was used for validation of this method because of the size dependence associated with XRD. The validation is applicable to the newer Final Rule V2O5 PELs because total dust is now excluded other than consideration as nuisance dust. The OSHA V2O5 PELs are currently for respirable dust or fume and are 8-h time weighted average (TWA) values (8.7.).

1.4. Vanadium Pentoxide (CAS 1314-62-1) Some Sources of Exposure (8.6.):

Application

Source of Exposure

catalyst oxidation of nitrogen and sulfuroxides

colorant manufacture of yellow glass

developer photography industry

coating using welding rods

alloys manufacture of special steels

contaminant cleaning fuel oil burners

1.6. Toxicology

Information contained in this section is a synopsis of current knowledge of the physiological effects of V2O5 and is not intended as a basis for OSHA policy.

1.6.1. When inhaled, the chief effects of V2O5 are on the respiratory passages. Tracheitis, bronchitis, emphysema, pulmonary edema, or bronchial pneumonia may be observed, but no specific chronic lung lesions have been described. Other symptoms reported include eye irritation, conjunctivitis, dermatitis, green tongue, metallic taste, throat irritation, increased mucus, and cough (8.6.).

1.6.2. The toxic effects of V2O5 are primarily from exposures to dusts in the respirable particle-size range. Exposure to non-respirable dust can also produce toxic effects.

1.6.3. Death has been observed when animals were exposed to 70 mg/m3 for a few hours (8.6.).

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http://www.lenntech.com/Periodic-chart-ele...20of%20vanadium

Health effects of vanadium (data sheet)

The uptake of vanadium by humans mainly takes place through foodstuffs, such as buckwheat, soya beans, olive oil, sunflower oil, apples and eggs.

Vanadium can have a number of effects on human health, when the uptake is too high. When vanadium uptake takes places through air it can cause bronchitis and pneumonia.

The acute effects of vanadium are irritation of lungs, throat, eyes and nasal cavities.

Other health effects of vanadium uptake are:

- Cardiac and vascular disease

- Inflammation of stomach and intestines

- Damage to the nervous system

- Bleeding of livers and kidneys

- Skin rashes

- Severe trembling and paralyses

- Nose bleeds and throat pains

- Weakening

- Sickness and headaches

- Dizziness

- Behavioural changes

The health hazards associated with exposure to vanadium are dependent on its oxidation state. This product contains elemental vanadium. Elemental vanadium could be oxidized to vanadium pentoxide during welding. The pentoxide form is more toxic than the elemental form. Chronic exposure to vanadium pentoxide dust and fumes may cause severe irritation of the eyes, skin, upper respiratory tract, persistent inflammations of the trachea and bronchi, pulmonary edema, and systemic poisoning. Signs and symptoms of overexposure include; conjunctivitis, nasopharyngitis, cough, labored breathing, rapid heart beat, lung changes, chronic bronchitis, skin pallor, greenish-black tongue and an allergic skin rash.

Effects of vanadium on the environment

Vanadium can be found in the environment in algae, plants, invertebrates, fishes and many other species. In mussels and crabs vanadium strongly bioaccumulates, which can lead to concentrations of about 105 to 106 times greater than the concentrations that are found in seawater.

Vanadium causes the inhibition of certain enzymes with animals, which has several neurological effects. Next to the neurological effects vanadium can cause breathing disorders, paralyses and negative effects on the liver and kidneys.

Laboratory tests with test animals have shown, that vanadium can cause harm to the reproductive system of male animals, and that it accumulates in the female placenta.

Vanadium can cause DNA alteration in some cases, but it cannot cause cancer with animals.

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INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

ENVIRONMENTAL HEALTH CRITERIA 81

VANADIUM

World Health Orgnization Geneva, 1988

http://www.inchem.org/documents/ehc/ehc/eh...tm#PartNumber:1

8.4.2 Cleaning and related operations on oil-fired boilers

Bronchitis and conjunctivitis resulting from exposure to

soot (containing 6 - 11% vanadium) during the cleaning of the

stacks of oil-fired boilers were first recognized by Frost

(1951). Frost did not report any other effects, but, in a

subsequent report of a boiler-cleaning operation by Williams

(1952), sneezing, nasal discharge, lachrymation, sore throat,

and substernal pain occurred within 0.5 - 12 h of exposure.

Within 6 - 24 h, secondary symptoms developed; these consisted

of dry cough, wheezing, laboured breathing, lassitude, and

depression. In some cases, the cough became paroxysmal and

productive. Symptoms lessened only after removal from the

working environment for 3 days. Air sampling showed most of the

dust particles to be smaller than 1 µg. The vanadium concen-

tration ranged from 17.2 mg/m3 in a superheater chamber to

58.6 mg/m3 in a combustion chamber. Roshchin (1962) observed 8

cases of acute vanadium poisoning in workers who cleaned boiler

flues at power stations burning high-sulfur oil. Analysis of

soot deposits showed that the soot in the region of greatest

dust formation (the pipes of the steam superheater and water

economizer) contained from 24 to 40% vanadium pentoxide. The

workers carried out cleaning operations without respirators or

with respirators that did not provide the necessary protection.

After cleaning the boilers, the workers developed acute vanadium

poisoning: itching in the throat, sneezing, cough with difficult

expectoration, and smarting eyes. On the following days, the

symptoms became more severe. Tightness in the chest, sweating,

general weakness, conjunctivitis, and noticeable loss of weight

developed. On examination one week later, hyperaemia and oedema

of the fauces and posterior pharyngeal wall were observed.

Harsh breathing sounds and dry crepitations were heard in the

lungs. X-ray examination showed intensified lung markings in

the middle zones of the right and left lungs and thickening of

the fissure on the right. One month later, only one worker

still had cough, weakness, perspiration, loss of energy, and

dyspnoea. The other workers recovered quickly, with complete

disappearance of cough and shortness of breath.

In another study on workers engaged in boiler-cleaning

operations (Troppens, 1969), the symptoms were described as

similar to mild coryza or influenza with bronchitis. Following

recovery, workers were tired, debilitated, irritable, without

any appetite, and complained of watery eyes. The first symptoms

were swelling of face and eyes as early as 20 min after entering

the boiler area. Removal from exposure for 2 - 3 weeks resulted

in the disappearance of symptoms. Skin blemishes described as

allergic dermatoses were attributed to absorption of vanadium

through sensitive skin. Troppens claimed that there was an

increased susceptibility of the vanadium worker to asthmatic

bronchitis and emphysema.

An investigation is reported on 53 workers performing

emergency repair work on oil-fired power station boilers (Izycki

et al., 1971). They were exposed to vanadium pentoxide in

average concentrations of from 1.2 to 11 mg/m3 and also to

manganese, calcium, and nickel oxides, and sulfur compounds.

Characteristic features of both acute and chronic vanadium

poisoning included upper respiratory catarrh in 45%, increased

lung markings in 24.5%, and bradycardia in 22% of cases.

Persistent chronic changes in the respiratory tract (rhinitis,

pharyngeal catarrh, laryngitis, and changes in the paranasal

sinuses) were present in 45%.

Milby (1974) reported 21 cases of vanadium poisoning in

boilermakers installing new catalytic-converter tubes. This

work involved marble-sized pellets of vanadium containing 11.7%

V2O5. The dust formed during the shaking of these pellets had a

particle size of 1.1 - 1.5 µm. After working for 72 h, the

workers began to complain of nasal, eye, and bronchial

irritation. By the 4th day, most felt very ill, with signs of

irritation of the upper respiratory tract and eyes and pains in

the chest.

In a study by Garlej (1974) 50 workers engaged in the

cleaning of oil-fired boilers were compared with a control group

of 60 other workers. Boiler deposits contained 44 -65% V2O5;

the maximum exposure was estimated to be 10 mg/m3. Although no

clinical evidence of vanadium poisoning was seen, a number of

exposure-dependent positive biochemical reactions were found in

the boiler-cleaning group. Urinary excretion of delta-amino-

levulinic acid (ALA), porphobilinogen (PBG), and porphyrin

increased beyond the physiological limit, and the positive Nadi

reaction (with associated green fluorescence) occurred. The

increased excretion of cytochrome (as indicated by the Nadi

reaction) suggested oxidation through V2O5 of the thiol group

-SH cysteine in the protein carrier, resulting in decreased

binding of cytochrome in the mitochondria.

A study on 17 men who were engaged in cleaning boilers at an

electric generating station was reported by Lees (1980). In

addition to clinical findings, which were similar to those

described above, urine-vanadium levels were determined, and

pulmonary function measurements were made for a week following

exposure. Sixteen of the men wore protective clothing, and

respirators that were found to have about 9% leakage. One

workman volunteered to wear only a simple oro-nasal dust mask

for 1 h of exposure. The dust exposure level was estimated to

be 26 mg/m3; respirable dust (under 10 µm) was measured at

523 µg/m3 with a vanadium content of 15.3%. All of the men

developed reduced pulmonary function that had not fully returned

to normal in one week, but did so after one month. Reduced

function outlasted the clinical symptoms by several days. Fig. 3

shows the contrast in pulmonary reaction between the more

heavily exposed individual and one of the other workmen. The

urine-vanadium level of the volunteer was 280 µg/litre, whereas

those of the remainder of the workers were below 40 µg/litre.

Other observations of boiler-cleaning operations have been

made by Fallentin & Frost (1954), Sjöberg (1955), Thomas &

Stiebris (1956), Hickling (1958), and Kuzelova et al. (1975).

In terms of respiratory symptoms relating to boiler-cleaning, it

should be noted that sulfates and sulfuric acid may be present

in boiler soot and may be partly responsible for irritative

effects. Hudson (1964) suggested that the quick onset of

symptoms (lachrymation with nose and throat irritation) with

rapid recovery following removal from exposure is character-

istic of exposure to acid sulfates. Response to vanadium expo-

sure is characterized by some delay in the onset of irritative

symptoms (a few hours to several days) and persistence of

symptoms following removal from exposure (Hudson, 1964).

A recent report by Levy et al. (1984) concerned a

comparatively high incidence of severe respiratory tract

irritation in boilermakers (74/100), many of them welders in

areas without adequate ventilation, exposed to vanadium

pentoxide fumes in a power plant where conversion from oil- to

coal-burning occurred. The severe illness of 70 men caused an

average of 5 days of absence, some objective tests (e.g., FVC)

being markedly affected. The vanadium pentoxide content was

above the permissible exposure limit in 8 samples, and this

resulted in litigation for inadequate protection of the

workers.

Kuzelova et al. (1977) drew attention to the occupational

risk of chimney sweeps cleaning large-capacity heating

facilities in large housing settlements. This coincided with a

report of a detailed cross-sectional examination of 121 chimney

sweeps by Holzhauer & Schaller (1977) in the Federal Republic of

Germany with an average exposure duration of 19 years ( ± 5

years). Vanadium exposure was determined by personal samples,

and measurements between 0.73 and 13.7 mg vanadium pentoxide/day

were determined compared with 4 µg in the normal (average)

population. Urinary excretion was determined to be between 0.15

and 13 µg/litre, which was significantly higher than the values

in 31 referents. The main complaints of the chimney sweeps were

wheezing, rhinitis, conjunctival irritation, cough, sputum

dyspnoea, and hoarseness; there were no skin symptoms. A

prospective follow-up of the cohort was emphasized, but the

results are not yet available.

8.4.3 Handling of pure vanadium pentoxide or vanadate dusts

Health effects due to occupational handling of pure vanadium

pentoxide or vanadate dusts have been reported. Tara et al.

(1953) described the effects of vanadium exposure in 4 dock

workers who unloaded and bagged spilled calcium vanadate. The

symptoms (bronchitic wheezing sounds, dyspnoea, productive

cough, haemoptysis in one case, and headache) necessitated

interruption of the work after 1´ days. Zenz et al. (1962)

described an acute illness that occurred in 18 workers pellet-

izing pure vanadium pentoxide; it was characterized by a rapidly

developing mild conjunctivitis, severe pharyngeal irritation, a

non-productive persistent cough, diffuse rales, and broncho-

spasm. With severe exposure, 4 men complained of itching skin

and a sensation of heat in the face and forearms. The symptoms

became more severe after each exposure, suggesting a sensitivity

reaction, but their duration was not prolonged by repeated

exposures.

8.4.4 Other industries

Browne (1955) studied vanadium poisoning in 12 patients

exposed to exhaust fumes from gas turbines using heavy fuel oil.

Evidence of poisoning appeared between the first and 14th day of

exposure and consisted of conjunctivitis, rhinitis, cough,

crepitations, and dyspnoea. Bleeding appeared before the

rhinorrhoea.

Other occupations in which respiratory effects of vanadium

exposure have been reported include operations connected with

the gasification of fuel oil (Fear & Tyrer, 1958) and the

manufacture of phosphor for television picture tubes (Tebrock &

Machle, 1968). In the latter study, elevated blood pressure was

noted in men exposed to vanadium pentoxide.