Registration Dossier

Administrative data

Description of key information

Studies via the oral and inhalation route are not available for divanadium tris(sulphate), but for other vanadium substances. Of the limited effects noted following oral exposure of soluble vanadium substances, it appears most likely that effects on haematological parameters are the most consistently reported among a number of investigators.
Information on repeated dose toxicity following inhalation exposure to V2O5 is available in a NTP study (k_NTP 2002) with exposure of male and female rats and mice to V2O5 over 16-days, 3-months and 2-years. Pulmonary reactivity to vanadium pentoxide was also investigated following subchronic inhalation exposure in a non-human primate animal model. The rationale for read-across to divanadium tris(sulphate) is summarised below (see discussion).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
LOAEL
24 mg/kg bw/day
Study duration:
chronic
Species:
rat
Quality of whole database:
Several supportive studies exist.

Repeated dose toxicity: inhalation - local effects

Link to relevant study records
Reference
Endpoint:
chronic toxicity: inhalation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
1997-01-13 (first exposure) to 1999-01-11/15 (necropsy date)
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well reported study. Test procedure in accordance with generally accepted scientific standards and described in sufficient detail.
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study
Reference:
Composition 0
Qualifier:
no guideline followed
Principles of method if other than guideline:
Groups of 50 male and 50 female B6C3F1 mice (approx. 6-7 weeks old) were exposed to V2O5 aerosols at concentrations of 0, 1, 2 or 4 mg/m3 by inhalation, 6 hours/d, 5 d/wk, for 104 weeks. The body weight was controlled initially and body weight and clinical finding were recorded every 4 weeks (until week 89) and every 2 weeks from week 92 on. Animals were observed twice daily. Necropsy was performed at study end.
GLP compliance:
yes
Limit test:
no
Test material information:
Composition 1
Species:
mouse
Strain:
B6C3F1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Taconic Farms, Inc. (Germantown, NY)
- Age at study initiation: average age: 6 or 7 weeks old on the first day of the study
- Weight at study initiation: average body weight for week 1: 24.0-24.4 g (males) and 19.6-19.9 g (females)
- Housing: housed individually; stainless steel wire bottom (Hazleton Systems, Inc., Aberdeen, MD); cages and racks were rotated weekly.
- Diet: ad libitum, except during exposure periods; NTP-2000 pelleted diet (Zeigler Brothers, Inc., Gardeners, PA), changed weekly
- Water: ad libitum; tap water (Richland, WA, municipal supply water used) via automatic watering system
- Acclimation period: quarantined for 16 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 23.9± ca.2°C (75° ± 3° F)
- Humidity (%): 55% ± 15%
- Air changes (per hr): 15/hour
- Photoperiod (hrs dark / hrs light): 12 hours/day

IN-LIFE DATES: From: 1997-01-13 (first exposure) to 1999-01-11/15 (necropsy date)
- No further information on test material was stated.
Route of administration:
inhalation: aerosol
Type of inhalation exposure:
whole body
Vehicle:
air
Remarks on MMAD:
MMAD / GSD: MMAD = 1.0-1.3 µm, GSD = 2.3-2.8
Details on inhalation exposure:
- The generation and delivery system used in the 16-day special studies and the 2-year studies consisted of a linear dust feeder, a particle attrition chamber, and an aerosol distribution system. The linear dust feeder, a slide-bar dust-metering device, was composed of a shuttle bar, body, outlet port, and hopper. As the compressed-air-driven shuttle bar slid back and forth during generation, the metering port aligned with the hopper, which served as a reservoir for the bulk chemical, and was filled with a small amount of vanadium pentoxide powder. As the shuttle bar slid to the dispersing position, the metering port aligned with a compressed-air port in the body and a puff of air from this port dispersed the vanadium pentoxide into the particle attrition chamber. Generator output was regulated by adjusting the cadence of the shuttle bar. The particle attrition chamber used low fluid energy from an air jet tangential to the chamber to deagglomerate the vanadium pentoxide particles. After deagglomeration, the particles were swept into a classification zone where smaller particles exited to the distribution line; larger particles were thrown to the perimeter of the classifier by centrifugal force and were reentrained into the impacting air jet, and the process was repeated until the particles were sufficiently deagglomerated. The aerosol passed through the distribution lines to the exposure chambers. A pneumatic pump designed by the study laboratory was located at each chamber inlet and drew aerosol from the distribution line into the chamber inlet, where it was diluted with conditioned air to the appropriate concentration. Flow through the distribution line was controlled by Air-Vac pumps (Air-Vac Engineering, Milford, CT), and pressure was monitored by photohelic differential pressure gauges (Dwyer Instruments, Inc., Michigan City, IN).
- The Stainless steel chambers (Lab Products, Inc., Harford Systems Division, Aberdeen, MD), were designed so that uniform aerosol concentrations could be maintained throughout the chambers when catch pans were in place. The total active mixing volume of each chamber was 1.7 m³.

CHAMBER ATMOSPHERE CHARACTERIZATION
- The particle size distribution in each chamber was determined prior to the start of all studies, during the first week of the 16-day and 3-month studies, during the first 2 weeks of the 2-year studies, and monthly during the 3-month and 2-year studies.
- For the 16-day special studies and the 2-year studies, a Mercer-style seven-stage impactor was used. The stages (glass coverslips lightly sprayed with silicon) were analyzed by ICP/AES, and the relative mass collected on each stage was analyzed by probit analysis.

OTHER
- The uniformity of aerosol concentration in the inhalation exposure chambers without animals was evaluated before each of the studies began; concentration uniformity with animals present in the chambers was also measured. During the 16-day and 3-month studies, minor excursions in chamber uniformity values were observed in one or more exposure chambers, but these excursions had no impact on the studies. Chamber concentration uniformity was acceptable throughout the 16-day special studies and 2-year studies.
- The stability of vanadium pentoxide in the exposure system was tested with XRD analysis. XRD analyses indicated no detectable build-up of degradation products at a detection limit of approximately 1%.



Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- During all studies, chamber aerosol concentrations were monitored with real-time aerosol monitors (RAMs) that used a pulsed-light-emitting diode in combination with a silicon detector to sense light scattered over a forward angular range of 45° to 95° by particles traversing the sensing volume. The instruments respond to particles 0.1 to 20 μm in diameter.
- For the 16-day special studies and the 2-year studies, the sampling system consisted of a valve that multiplexed each RAM to two or three exposure chambers and to a HEPA filter and/or the control chamber or room; selection of sampling streams and data acquisition from each RAM was remotely controlled by a computer. Equations for calibration curves were stored in the computers and were used to convert the measured voltages to exposure concentrations.
- Each RAM was calibrated daily during the 16-day and 3-month studies by correlating the measured voltage with vanadium pentoxide concentrations determined by gravimetric analysis of glass fiber filters and one to two times per week during the 2-year studies by ICP/AES or ICP/mass spectrometry analysis of Pallflex® TX40H120WW glass fiber filters.
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
6 hours per day, 5 days per week
Remarks:
Doses / Concentrations:
1 mg/m³ V2O5
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
2 mg/m³ V2O5
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
4 mg/m³ V2O5
Basis:
nominal conc.
No. of animals per sex per dose:
core study: 50 males and 50 females per dose
tissue burden analyses: 40 female mice per exposed group; separate control group of 15 female mice was used as chamber controls
Control animals:
yes
Details on study design:
- Dose selection rationale: the highest exposure concentration (4 mg/m3) selected for mice was based on reduced body weight gains of 8 and 16 mg/m3 males and females, increased lung weights of 4 mg/m3 or greater males and females, increased incidences of epithelial hyperplasia, and increased incidences and severities of inflammatory lesions of the lungs in mice exposed to 8 mg/m3 versus those exposed to 4 mg/m3 in the 90-day study.
- Rationale for animal assignment (if not random): randomly into groups of approximately equal initial mean body weights.
- No further information on test material was stated.
Positive control:
not stated
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: All animals were observed twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Clinical findings were recorded every 4 weeks from week 5 through 89 and every 2 weeks from week 92 to the end of the study

BODY WEIGHT: Yes
- Time schedule for examinations: animals were weighed at the beginning of the studies. Body weights were recorded every 4 weeks from week 5 through 89 and every 2 weeks from week 92 to the end of the study

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION: No data

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: No

CLINICAL CHEMISTRY: No

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

OTHER:
Tissue Burden Studies:
- Lungs and whole blood were collected from five mice in each exposure group sacrificed on day 1, 5, 12, 26, 54, 171, 362, or 535. Groups of five chamber control animals were bled at each of these time points and returned to their chambers and used for subsequent bleedings. The lungs and associated tissues were removed from exposed animals; after the left and right lung were prepared for histopathologic examination, and the right lung was digested to measure vanadium concentration. Vanadium concentrations in blood and right lung nitric acid digests were measured. Calculations of lung deposition and clearance parameters were performed. Blood vanadium concentration was measured in all animals at all time points after day 12.
Sacrifice and pathology:
Method of Sacrifice: CO2 asphyxiation.

PATHOLOGY: Yes
- Complete necropsies were performed on all core study mice.
- All organs and tissues were examined for grossly visible lesions, and all major tissues were prepared for microscopic examination.

HISTOPATHOLOGY: Yes
- Complete histopathology was performed on all core study animals. In addition to gross lesions and tissue masses, the following tissues were examined: adrenal gland, bone with marrow, brain, clitoral gland, esophagus, gallbladder (mice only), heart and aorta, large intestine (cecum, colon, and rectum), small intestine (duodenum, jejunum, and ileum), kidney, larynx, liver, lung and mainstem bronchi, lymph nodes (mandibular, mediastinal, mesenteric, and bronchial), mammary gland (except male mice), nose, ovary, pancreas, parathyroid gland, pituitary gland, preputial gland, prostate gland, salivary gland, skin, spleen, stomach (forestomach and glandular), testis (with epididymis and seminal vesicle), thymus, thyroid gland, trachea, urinary bladder and uterus.
Other examinations:
Five male and five female mice were randomly selected for parasite evaluation and gross observation of disease.
Statistics:
Survival Analyses:
The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958) and is presented in the form of graphs. Animals found dead of other than natural causes were censored from the survival analyses; animals dying from natural causes were not censored. Statistical analyses for possible doserelated effects on survival used Cox’s (1972) method for testing two groups for equality and Tarone’s (1975) life table test to identify dose-related trends. All reported P values for the survival analyses are two sided.

Analysis of Continuous Variables:
Two approaches were employed to assess the significance of pairwise comparisons between exposed and control groups in the analysis of continuous variables. Organ and body weight data, which historically have approximately normal distributions, were analyzed with the parametric multiple comparison procedures of Dunnett (1955) and Williams (1971, 1972). Hematology, clinical chemistry, urinalysis, urine concentrating ability, cardiopulmonary, immunotoxicologic, cell proliferation, tissue concentrations, spermatid, and epididymal spermatozoal data, which have typically skewed distributions, were analyzed using the nonparametric multiple comparison methods of Shirley (1977) and Dunn (1964). Jonckheere’s test (Jonckheere, 1954) was used to assess the significance of the dose-related trends and to determine whether a trend-sensitive test (Williams’ or Shirley’s test) was more appropriate for pairwise comparisons than a test that does not assume a monotonic dose-related trend (Dunnett’s or Dunn’s test). Average severity values were analyzed for significance with the Mann-Whitney U test (Hollander and Wolfe, 1973). Treatment effects were investigated by applying a multivariate analysis of variance (Morrison, 1976) to the transformed data to test for simultaneous equality of measurements across exposure concentrations. (for more information see publication)
Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
effects observed, treatment-related
Details on results:
CLINICAL SIGNS AND MORTALITY
- Survival of the highest dosed males (4 mg/m³) was significantly less than controls
- Abnormal breathing was observed particularly those exposed to 2 or 4 mg/m³
- Many mice exposed to vanadium pentoxide were thin

BODY WEIGHT AND WEIGHT GAIN
-Mean body weight of all females and highest dosed males was below the controls; and mean body weights of males exposed to 2 mg/m3 were less from week 85 to the end of the study

HISTOPATHOLOGY: NON-NEOPLASTIC
- Non-neoplastic lesions occurred in respiratory system (lung, larynx, and nose) of males and females, and the severities of these lesions generally increased with increasing exposure concentration.
-Bronchial lymph node hyperplasia was present in most of the exposed females.

LUNG:
- There were significantly increased incidences of alveolar epithelial hyperplasia and bronchiolar epithelial hyperplasia in the lungs of exposed male and female mice. Incidences of chronic inflammation and histiocytic cellular infiltrate were significantly increased in exposed groups of mice, and the incidences of interstitial fibrosis were increased in mice exposed to 2 or 4 mg/m3.
- Males: alveolar epithelium, hyperplasia (3/50, 41/50, 49/50, 50/50); bronchiole, epithelium, hyperplasia (0/50, 15/50, 37/50, 46/50); inflammation chronic (6/50, 42/50, 45/50, 47/50); alveolus, infiltration cellular, histiocyte (10/50, 36/50, 45/50, 49/50); interstitial fibrosis (1/50, 6/50, 9/50, 12/50)
- Females: alveolar epithelium, hyperplasia (0/50, 31/50, 38/50, 50/50); bronchiole, epithelium, hyperplasia (0/50, 12/50, 34/50, 48/50); inflammation chronic (4/50, 37/50, 39/50, 49/50); alveolus, infiltration cellular, histiocyte (0/50, 34/50, 35/50, 45/50); interstitial fibrosis (0/50, 1/50, 4/50,
8/50)
- The hyperplasia was essentially a diffuse change with proliferation of epithelium in the distal terminal bronchioles and immediately associated alveolar ducts and alveoli. Normally flattened epithelium was replaced with cuboidal epithelium. The hyperplasia of the alveolar epithelium was pronounced and increased in severity with increasing exposure concentration, while the hyperplasia of the distal bronchioles was minimal to mild with slight increases in severity in mice exposed to 4 mg/m3. The changes in mice were similar to those observed in rats but were not as pronounced.
- The inflammatory lesions were primarily minimal to mild and consisted of interstitial, perivascular, and peribronchiolar infiltrates of mostly mononuclear inflammatory cells (mostly lymphocytes) that were occasionally present within alveoli. The most prominent histiocytic infiltrate occurred within alveoli in close proximity to alveolar/bronchiolar neoplasms, particularly carcinomas.

LARYNX:
- There were significantly increased incidences of minimal squamous metaplasia of the respiratory epithelium of the epiglottis in exposed groups.
- Males: respiratory epithelium, epiglottis, metaplasia, squamous (2/49, 45/50, 41/48, 41/50)
- Females: respiratory epithelium, epiglottis,metaplasia, squamous (0/50, 39/50, 45/49, 44/50)
- Squamous metaplasia was diagnosed when the ciliated cells were replaced by one to three layers of flattened squamous epithelium. This change commonly occurs in mice in NTP inhalation studies and represents a common response to laryngeal injury.

NOSE:
- There were increased incidences of minimal to mild suppurative inflammation of the nose in males and females exposed to 2 or 4 mg/m3.
- Males: inflammation suppurative (16/50, 11/50, 32/50, 23/50); olfactory epithelium, degeneration, hyaline (1/50, 7/50, 23/50, 30/50); respiratoryepithelium, degeneration, hyaline (8/50, 22/50, 38/50, 41/50); respiratory epithelium, metaplasia, squamous (0/50, 6/50, 6/50, 2/50)
- Females: inflammation suppurative (19/50, 14/50, 32/50, 30/50); olfactory epithelium, atrophy (2/50, 8/50, 5/50, 14/50); olfactory epithelium, degeneration, hyaline (11/50, 23/50, 34/50, 48/50); respiratory epithelium, degeneration, hyaline (35/50, 39/50, 46/50, 50/50); respiratory epithelium, metaplasia, squamous (0/50, 3/50, 7/50, 8/50); respiratory epithelium, necrosis (0/50, 0/50, 1/50, 7/50)
- The inflammation consisted of focal aggregates of few to moderate numbers of neutrophils generally subjacent to the epithelium of the turbinates, septum, or lateral wall of the anterior nose. In the more severe cases (predominantly in females exposed to 4 mg/m3), a short segment of the overlying epithelium was ulcerated (necrosis). Similarly, in some males and females, the overlying respiratory epithelium was replaced by one or more layers of flattened epithelium (squamous metaplasia), and the incidences were marginally increased in some exposed groups of mice.
- The majority of the olfactory epithelium covers the turbinates in the distal portion of the nose. There were marginal but significant increases in the incidences of atrophy of this epithelium in females exposed to 1 or 4 mg/m3.

BRONCIAL LYMPH NODE
- There were significant increases in the incidences of hyperplasia of the bronchial lymph node in exposed groups of females, and while not significant, a positive trend in the incidences of this lesion also occurred in males.
- Females: hyperplasia (3/39, 13/40, 14/45, 20/41)

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
LUNG:
- The incidences of alveolar/bronchiolar carcinoma and alveolar/bronchiolar adenoma or carcinoma (combined) were significantly increased in all groups of exposed male and female mice compared to controls
- Males: alveolar/bronchiolar adenoma (13/50, 16/50, 26/50, 15/50); alveolar/ bronchiolar carcinoma (12/50, 29/50, 30/50, 35/50); alveolar/ bronchiolar adenoma or carcinoma (22/50, 42/50, 43/50, 43/50)
- Females: alveolar/bronchiolar adenoma (1/50, 17/50, 23/50, 19/50); alveolar/ bronchiolar carcinoma (0/50, 23/50, 18/50, 22/50); alveolar/ bronchiolar adenoma or carcinoma (1/50, 32/50, 35/50, 32/50)
- The incidences of alveolar/bronchiolar adenoma were significantly increased in males exposed to 2 mg/m3 and in all groups of exposed females.
- These increased incidences exceeded the historical ranges for controls.

SPLEEN:
- There was a positive trend in the incidences of hemangiosarcoma of the spleen in male mice (chamber control, 0/50; 1 mg/m3, 0/50; 2 mg/m3, 0/50; 4 mg/m3, 3/50).
- However, the incidence in the 4 mg/m3 group was within the historical range in controls.
- In addition, the incidences of hemangioma or hemangiosarcoma (combined) in all organs were not significant. The marginal increase in the incidence of hemangiosarcoma of the spleen was not considered related to vanadium pentoxide exposure.

OTHER FINDINGS
TISSUE BURDEN STUDIES:
- Histopathology: lung lesions were identified early, and were more severe in females exposed to higher concentrations and progressed with time. Minimal bronchiolar epithelial hyperplasia and interstitial inflammation were initially observed in the 4 mg/m3 group on day 5. Bronchiolar epithelial hyperplasia was characterized by slight piling up of cells, some nuclear pleomorphism, and occasional karyorrhectic cells. On day 12, exposure-related lesions were evident in 2 mg/m3 females, while alveolar epithelial hyperplasia was more prominent in the 4 mg/m3 group. Lesions were first observed in the 1 mg/m3 group on day 54, and lesion severities in the 2 and 4 mg/m3 groups appeared to be increased on day 54. On day 362, lesion severity in lungs of females exposed to 4 mg/m3 was noticeably increased, and bronchiolar hyperplasia included more nuclear pleomorphism. On day 535, mice exposed to 2 mg/m3 had hyperplastic alveolar epithelial lesions and, similar to females exposed to 4 mg/m3, the hyperplasia was oriented around the terminal bronchiolar/alveolar duct. Also on day 535, lung nodules/masses were observed. While some were confirmed as neoplasms, many were in the right lung lobe and thus were not confirmed histopathologically. Similar lesions, although more severe, were observed in the core group of animals at 2 years.
- Lung burden data appeared proportional to exposure concentration in mice. Rats removed vanadium from the lungs much slower than mice, with clearance half-times of vanadium lung burdens approximately six to nine fold longer in rats than in mice at comparable exposure concentrations. In rats and mice, lung clearance half-times were considerably longer than those observed in the 16-day special studies.
- The maximum lung burdens occurred between days 26-54 in mice. The lung burdens appeared to reach steady state at the lowest exposure concentrations (1 mg/m3). A decline in lung burdens was observed. The retention of vanadium in the lungs at 18 months was 2% to 3% in mice. The total lung doses for mice exposed to 1, 2, or 4 mg/m3 were estimated to be 153, 162, and 225 μg vanadium, respectively. There was little difference in the total lung dose for mice, especially between the 1 and 2 mg/m3 groups.
Dose descriptor:
NOAEL
Remarks:
local
Effect level:
1 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: non-neoplastic changes (epithelial hyperplasia, squamous metaplasia, chronic inflammation, degeneration) in the respiratory system (lung, larynx, and nose) of male and female mice
Critical effects observed:
not specified

Chamber concentration uniformity was acceptable throughout the 16-day special studies and 2-year studies.

Conclusions:
The survival rate of male mice exposed to 4 mg/m3 was less than that of chamber controls, and mean body weights of male mice exposed to 4 mg/m3 and all exposed groups of female mice were generally less than those of the chamber controls throughout the study. As in the 3-month studies, the respiratory tract was the primary site of toxicity.
Under the conditions of this 2-year inhalation study there was clear evidence of carcinogenic activity of vanadium pentoxide in male and female B6C3F1 mice based on increased incidences of alveolar/bronchiolar neoplasms. Exposure to vanadium pentoxide caused a spectrum of non-neoplastic lesions in the respiratory tract (nose, larynx, and lung) including alveolar and bronchiolar epithelial hyperplasia, inflammation, fibrosis, and alveolar histiocytosis of the lung in male and female mice. Hyperplasia of the bronchial lymph node occurred in female mice. The lowest concentration tested (1 mg/m3) represents a LOAEC for local effects in the respiratory tract.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LOAEC
2.24 mg/m³
Study duration:
chronic
Species:
rat
Quality of whole database:
Findings in rat model may not be relevant for humans. Further, inhalation may not be a relevant route of exposure for divanadium tris(sulphate) (solution).

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: dermal
Data waiving:
other justification
Justification for data waiving:
other:
Critical effects observed:
not specified
Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: dermal
Data waiving:
other justification
Justification for data waiving:
other:
Critical effects observed:
not specified
Endpoint conclusion
Endpoint conclusion:
no study available

Mode of Action Analysis / Human Relevance Framework

Additional information

Studies via the oral and inhalation route are not available for divanadium (tris)sulphate, but for other vanadium substances. The registrant is of the opinion that the toxicity ofdivanadium tris(sulphate) is driven by the vanadium moiety and that the sulfate anion does not contribute to the overall toxicity ofdivanadium tris(sulphate)to any relevant extent, for the following reasons:

Sulfate anions are abundantly present in the human body in which they play an important role for the ionic balance in body fluids. Sulfate is required for the biosynthesis of 3′-phosphoadenosine-5′-phosphosulfate (PAPS) which in turn is needed for the biosynthesis of many important sulfur-containing compounds, such as chondroitin sulfate and cerebroside sulfate.TheJoint FAO/WHO Expert Committee on Food Additives (JECFA) concludes that the few available studies in experimental animals do not raise any concern about the toxicity of the sulphate ion in sodium sulphate. Sodium sulphate is also used clinically as a laxative. In clinical trials in humans using 2-4 single oral doses of up to 4500 mg sodium sulphate decahydrate per person (9000 – 18000 mg per person), only occasional loose stools were reported. These doses correspond to 2700 - 5400 mg sulphate ion per person. High bolus dose intake of sulphate ion may lead to gastrointestinal discomfort in some individuals. No further adverse effects were reported (JECFA 2000, 2002). This position was adopted by the European Food Safety Authority (EFSA2004) without alteration.

Based on the above information, one can therefore safely assume that the sulfate anion in divanadium tris(sulphate)does not contribute to the overall toxicity of divanadium tris(sulphate). It is concluded that only the effect of “vanadium” is further considered in the human health hazard assessment of divanadium tris(sulphate). The rationale for read-across to divanadium tris(sulphate) can be summarised according to the following relevant routes of exposure:

Oral:

A number of studies are available where vanadium compounds were administered, however they have involved different experimental approaches and designs as well as different dose regimens, and endpoints. The most consistent effect of exposure to V2O5, i.e. pulmonary irritation and inflammation, is associated with the inhalation route. For oral exposure to vanadium substances, effects are more limited and the different experimental approaches lead to a variety of endpoints measured. Of the limited effects noted following oral exposure, it appears most likely that effects on haematological parameters are the most consistently reported among a number of investigators (Mountain et al 1953, Zaporowska et al. 1993, Scibior et al 2006, Scibior, 2005, NTP, 2002).

In a study (treatment of male rats for 103 days) with the focus on reduction of the cysteine content in rat hair (Mountain et al. 1953), reduced erythrocyte counts and levels of hair cysteine were observed dose-dependently at dose levels of 100 and 150 ppm in the diet. Effects on hair cysteine levels and on red blood cell parameters may correlate with erythropenia and anaemia. Similar haematological effects were observed by Zaporowska et al. (1993) in a 4-week toxicity study. Rats received NH4VO3at dose levels of 1.5 and 5-6 mg V/kg bw/d via drinking water.

Haematological examinations showed a decrease in erythrocyte counts (associated with increased reticulocyte counts), haemoglobin and haematocrit levels in both groups. Effects of vanadium and chromium on body weight gain and selected haematological and blood parameters in rats were also investigated by Scibior (2005) following administration of NaVO3to rats via drinking water for a period of 6 weeks. Treatment of rats with about 8 mg V/kg bw/d resulted in effects on body weight and erythrocytes (increased no. of erythrocytes, haemoglobin, and decrease of MCV, MCH, MCHC and leucocytes).

Altogether, effects noted have included reduced haemoglobin, reduced haematocrit, reduced mean cell haemoglobin concentrations, while effects on red blood cells have included both reductions and increases depending on dose levels used and duration of treatment, perhaps compensating for the haemoglobin effect. Haematological effects have been found with a variety of different vanadium compounds including sodium metavanadate, vanadium pentoxide, and ammonium metavanadate supporting the use of this endpoint.

The fact that evidence of haematological effects was also observed following 90-day inhalation exposure to vanadium pentoxide, in the absence of other remarkable systemic toxicity (NTP, 2002), increases the confidence in this being the appropriate critical effect for oral exposure from the available dataset. Additional support for the reliability of this endpoint comes from a study by Hogan (2000), where haematological effects were demonstrated following IV injection of three different vanadium compounds each with a different valence state (vanadium chloride (V-III); vanadyl sulphate (V-IV); and sodium orthovanadate (V-V)).

Few other signs of systemic toxicity following oral ingestion of vanadium compounds have been reported in other studies, but they do not show a consistent picture. In a study conducted by Domingo et al. (1985), some evidence for renal effects were reported following exposure for 3 months to sodium metavanadate however the effects (increased plasma protein, urea and uric acid) were limited to the top dose with the mid and low dose not being affected. Organ weights, including kidneys, were not affected, and histopathology data were not reported (Domingo et al. (1985). Other studies (Susic and Kentera 1988; NTP 2002) including some assessment of renal function have not shown similar effects although only limited information is available. However, in a study in rats with chronic dietary administration (24 wks) of vanadate (Susic & Kentera, 1988), changes were seen in cardiac output and total peripheral resistance at dose levels of 300 and 3000 ppm NaVO3in the diet. In addition, there was an effect on haematocrit (increase), plasma and blood volume (decrease) as well as extracellular fluid in the high dose group. In another subchronic study (2 months) by Susic & Kentera (1986), 300 ppm represents an effect level for pulmonary function. In this study, no effects were observed on haematocrit levels. The results of a study reported by Jadhav and Jandhyala (1983) suggest that the cardiovascular system responded to vasoconstrictor agents in a dose-dependent manner after subchronic (6 weeks) oral vanadate exposure (drinking water) favouring the development of high blood pressure.In a subchronic study (8 weeks) on behavioural effects of orally administered NaVO3in rats, effects on general activity and learning were observed already at the lowest dose level of 4.1 mg/kg bw/d(Sanchez et al. 1998).Treatment of male rats with different dose levels of vanadyl sulfate in drinking water corresponding to 34, 54 and 90 mg/kg bw/day over 52 weeks did not indicate severe signs of systemic toxicity under the conditions of this study. Body weights were dose-dependently reduced in treatment groups compared to controls, occasionally reaching statistical significance in the low and mid dose groups and at most time points in the high dose group. Based on these effects, the lowest dose level of 34 mg/kg bw/d represents a LOAEL.

Based on the available limited data on repeated dose toxicity following oral exposure of soluble tetra- and pentavalent vanadium substances, effects on red blood cell parameters can be regarded as the most robust effect of systemic toxicity. This is further backed by results from a 90-day NTP study (2002) with inhalation exposure of rats. Of the studies showing haematological effects, several of the studies measured the effect with one dose of vanadium compound while other treatment groups received vanadium combined with other substances. These studies are regarded as supportive. Results from the Mountain et al. study (1953) were selected as the starting point for derivation of the DNEL for oral exposure, because it represents the study with the longest duration (103 days) and included several dosage groups. Although the effects observed at the low dose level of 100 ppm V in the diet are only minimal, this dose level is regarded to represent a LOEL in order to protect for potential other toxicological effects. Almost similar results were obtained by Zaporowska et al. (1993) in a 4-week toxicity study, but as the study is only of short-term duration, it is considered as supportive.

Conversion of LOEL (ppm in diet) to LOEL (mg/kg bw /d):

LOEL:              100 ppm V                  Duration:                                 103 d

Food intake:    2,130 g/rat                   Body weight (kg bw/rat):          0.5 kg

V ingested reported:                           155 mg V/rat/103 d= 1.5 mg V/kg

LOELcorrected= 3.0 mg V/kg bw/d based on exposure to soluble vanadium forms

Read-across: The read-across approach based on dissolved vanadium is based on the assumption that once inorganic vanadium compounds dissolve or become bioavailable, this will be in tetra- or pentavalent vanadium forms. In bioaccessibility tests of tri-, tetra- and pentavalent vanadium substances, tetra- and pentavalent forms dissolved within 2h in various media selected to simulate relevant human-chemical interactions (i.e. PBS mimicking the ionic strength of blood, artificial lung, lysosomal, and gastric fluid as well as artificial sweat). Tri-, tetra- and pentavalent vanadium substances are retained as pentavalent forms in physiological media, with the exception of artificial lysosomal fluid in which tetravalent V dominates after 2h and is the only form present after 24h. Thus, read-across of repeated-dose toxicity data from soluble tetra-- and pentavalent vanadium substances is justified.

Inhalation:

The most informative study is the standard NTP chronic inhalation study (NTP 2002) using V2O5. In this investigation, there was a statistical increase in lung tumours in mice of both sexes, but not in rats (Starr, 2012). In mice, survival rates of male mice exposed to 4 mg/m3 was less than that of chamber controls, and mean body weights of male mice exposed to 4 mg/m3 and all exposed groups of female mice were generally less than those of the chamber controls throughout the study. As in the 3-month studies, the respiratory tract was the primary site of toxicity. Under the conditions of this 2-year inhalation study there was clear evidence of carcinogenic activity of vanadium pentoxide in male and female B6C3F1 mice based on increased incidences of alveolar/bronchiolar neoplasms. Exposure to vanadium pentoxide caused a spectrum of non-neoplastic lesions in the respiratory tract (nose, larynx, and lung) including alveolar and bronchiolar epithelial hyperplasia, inflammation, fibrosis, and alveolar histiocytosis of the lung in male and female mice. Hyperplasia of the bronchial lymph node occurred in female mice. The lowest concentration tested (1 mg/m3) represents a LOAEC for local effects in the respiratory tract.

Pulmonary reactivity was also investigated in a subchronic inhalation study in cynomolgus monkeys (duration 6 months) with divanadium pentaoxide. The results showed a concentration-dependent impairment in pulmonary function, characterized by airway obstructive changes (pre-exposure challenges) accompanied by a significant influx of inflammatory cells recovered from the lung by bronchoalveolar lavage. Subchronic V2O5 inhalation did not produce an increase in V2O5 reactivity, and cytological, and immunological results indicate the absence of allergic response.

Human data: Regarding the preferential use of human data in risk assessments for human health, a respective statement is attached below. There are several epidemiological studies linking upper respiratory symptoms to vanadium pentoxide exposure (Kiviluoto, 1980; Kiviluoto et al., 1979a; Lewis, 1959, Zenz and Berg, 1967 Zenz et al. 1962). Long-term chronic exposure data of workers in the vanadium industry are reported in several publications. In a factory manufacturing vanadium pentaoxide, 63 workers exposed to V2O5at concentrations of 0.1 to 3.9 mg V/m3measured as total dust for 11 years (average 0.2-0.5 mg V/m3) did not have an increased prevalence of upper respiratory symptoms in the case study by Kiviluoto et al (1979a,b, 1980, 1981a,b).

Kiviluoto et al. (1979b) did not observe any differences in the anterior and posterior rhinoscopy in the exposed groups after 11 years of exposure to average V2O5levels of 0.2-0.5 mg V/m3as listed above. Furthermore, there was no difference in the number of blood vessels between the exposed and non-exposed groups. However, the number of neutrophils in the nasal smears and the number of plasma cells in the nasal mucosa were increased indicative of a protective mechanism in the mucosa. Other examined factors of the biopsies and cell findings did not differ between the exposed workers and the controls. Chest radiographs and lung function tests did not reveal any differences. After further 7-11 months of V2O5exposure at concentrations ranging from 0.01 to 0.04 mg V/m3measured as total dust, a subsequent reexamination revealed that the cell findings did not indicate any further significant changes between the studied exposed groups, and that there were no significant changes in the number of eosinophils of cytological and histological samples.

Altogether, no pneumoconiosis and no other signs indicative of allergic inflammation, including nasal catarrh, cough, phlegm, were observed by Kiviluoto et al. in the exposed subjects working for 11 years under these occupational conditions.

 Other epidemiological data support that respiratory symptoms are observed at exposure concentrations of V2O5that are above 0.1 mg/ V/m3, and are summarized in the following table

Table: Epidemiological studies ofV2O5exposure

Subjects

V2O5Dose

[mg V /m3]

Exposure duration

Symptoms

study

24 workers

0.1 - 0.93

mean PS < 5 μm

 

eye, nose, throat irritation;

cough; wheezing, nasal mucosa,

rales, rhonchi; injected

pharynx and green tongue

Lewis, 1959

2 volunteers

1

8 h

cough, no eosinophilia, normal white blood cell count & cell patterns, no effects on urinalysis, normal lung function

Zenz & Berg, 1967

5 volunteers

0.2

(PS: 98 % < 5 μm)

8 h

loose cough, no eosinophilia, normal white blood cell count & cell patterns, no effects on urinalysis, normal lung function, no detectable V in the blood

Zenz & Berg, 1967

2 volunteers

0.1

8 h

formation of mucus

Zenz & Berg, 1967

3 of 18 workers

> 0.5

mean PS < 5 μm

24 h

inflamed throat, dry cough, burning eyes, no wheeze

Zenz et al. (1962)

11 volunteers

 

0.4

condensation aerosol

 

tickling, itching, dryness of mouth mucosa

Pazhynic, 1967

5 of 11 volunteers

0.16

 

mild signs of irritation

Pazhynic, 1967

11 volunteers

0.08

 

no notice of symptoms

Pazhynic, 1967

8 volunteers

(4 workers + 4 trainees)

0.028 – 0.062

8 h/d, 5 d

no notice of symptoms (i.e. neurobehavioural, neuro-psychological, psychosomatic & psychological effects)

Hörtnagl et al. 1994

 

The Scientific Committee on Occupational Exposure Limit summarized these studies as follows:„In workers exposed to dust containing vanadium (as vanadium pentaoxide) 0.2-0.5 mg/m3for about 11 years, irritants effects on the mucous membranes of the upper respiratory tract were reported. After hygienic improvements, the same workers were exposed to VP concentrations in the range of 0.01-0.04 mg/m3for about 10 months. No worsening of the irritant effects observed as a consequence of the previous exposure was reported for this low-level exposure. In these workers, the exposure did not cause any pathological effects on the blood picture, the cysteine level in the hair, or the respiratory function (Kiviluoto et al., 1979a,b, 1980, 1981a,b; Kiviluoto, 1980)…

Kiviluoto et al (1979a,b, 1980, 1981a,b): in their studies on 63 males exposed in a vanadium factory for 11 years at concentrations in the range of 0.1-3.9 mg/m3(estimated average concentrations 0.2-0.5 mg/m3) and after a further 7-11 month later when concentrations had been reduced to 0.01-0.04 mg/m3studied nasal smears and biopsies. The findings were consistent with irritant effects. Eosinophils did not differ between exposed and non-exposed, nor did IgE-antibody levels. Although exposed workers complained significantly more often of wheezing, pulmonary function tests did not differ. There is, thus, little evidence indicating sensitizing effects on the respiratory tract. The known irritant effects of VP can well explain effects on the respiratory tract including rhinitis, bronchial hyper-reactivity, wheeze, asthma as well as bronchitis…

 

For respiratory tract irritation, and more generally speaking for upper and lower airways effects, dose-response relationships could be obtained in both experimental animals and humans. It can be assumed that 0.04 mg/m3 has to be considered as a NOEL in occupationally exposed subjects (10 months), while in rodents a NOEL could be concluded at an exposure level of 2 mg/m3(B6C3F1 mice, m. f., inhalation, 6h/day, 5d/w for 16 days) and of 1 mg/m3 (F344/N rats, m. f., inhalation, 6h/day, 5d/w for 14 weeks)…

It appears that exposure to concentrations <0.1 mg/m3do not induce irritating effects on the respiratory tract.(SCOEL/SUM/62 Final, January 2004)“

Evidence from animal and human data suggests that exposure to elevated V2O5concentrations may result in irritating effects on the respiratory system. However, human data were used as point of departure for the DNEL derivation because long-term chronic data are available from workers exposed to vanadium dust using a sensitive indicator of irritation (cytology), a population similar to the target population (workers of the vanadium industry), and to decrease uncertainty for interspecies differences in sensitivity.

Therefore, the NOAEC of 0.04 mg V /m3(measured as total dust) for humans exposed occupationally for 11 years to V2O5dust was used as POD for the DNEL derivation.

 

Read-across:There is a complete lack of studies that would allow distinguishing whether or not local effects of V2O5are relevant for other vanadium substances. Based on the assumption that irritancy of a particular V substance is the driver for local effects, read-across of irritating effects of V2O5to other soluble vanadium substances was assessed. Five substance-specific properties are assumed to predominantly account for the observed irritation potential of V2O5: (i) water solubility and potential to become bioavailable, (ii) acidifying properties in aqueous media and potential for related burning, (iii) oxidising properties and potential for oxidative injury, (iv) irritating /corrosive properties (skin and/or eye) and potential for irritation of mucous membranes, and (v) particle size distribution and potential for inhalability. Divanadium tris(sulphate) is assessed as follows: 

(i) Divanadium tris(sulphate) with a water solubility of 660 g/L at 20°C/pH< 0 is considered very soluble.

(ii) Divanadium tris(sulphate) has an acidifying effect as in the water solubility test, a pH < 0 was measured. 

(iii) Divanadium tris(sulphate) is completely void of oxidising properties and the potential for oxidative injury.

(iv) Where available data indicates any irritating effects either to skin, eye or respiratory tract, it was assumed in a conservative approach that the respective substance may have an irritation potential. Hence, divanadium tris(sulphate) is considered as a substance with irritation potential.

(v) The inhalability as an additional modifying factor was derived from particle size distributions (i.e., granulometry), for which all vanadium substances were subjected to an experimental testing programme. Physical particle size distributions of commercial materials were determined experimentally and are represented by the median particle size diameter (d50).

Since “physical” particle size distributions do not necessarily reflect the particle size of aerosols that may be formed under practically relevant workplace conditions (e.g., during manual operations, including bag filling and emptying, or under mechanical agitation during mixing and weighing), the particle size distribution of the airborne fraction generated during mechanical agitation in the rotating drum according to the method by Heubach (1991) was additionally determined according to DIN 55992 Part 1. Furthermore, using the mass fractions deposited on the impactor stages, mass median aerodynamic diameter (MMAD) of the airborne material and geometric standard deviation (GSD) of the MMAD were determined (Grewe, 2010 & 2013). The Multiple Path Particle Deposition (MPPD) model (CIIT, 2002-2009) was applied to estimate the deposition of particles in the respiratory tract (head, tracheobronchial and pulmonary region) of workers. As a result, divanadium tris(sulphate) was assessed as being (at least partly) inhalable based on MPPD model outputs using worker specific input parameters as well as MMAD and GSD estimates.

 

If a V substance possesses four or more of the five substance-specific properties assumed to predominantly account for the observed irritation of V2O5, read-across of irritating effects of V2O5is considered to be justified in a conservative approach (see Table below).

 

 

potential to become bioavailable

potential for acidic burning

potential for inhalability

potential for oxidative injury

potential for irritation of mucous membranes

Read-across of irritation

V2(SO4)3

yes

yes

*

no

yes

yes

* V2(SO4)3 is manufactured and sold in solution only and as such are not inhaled. However, for pre-cautionary considerations, the solid product is being assessed and inhalability was nevertheless assumed.

 

As already stated, the applied approach is likely to overestimate the potential of divanadium tris(sulphate) to irritate mucous membranes. However, in the absence of further data, a differentiation cannot be scientifically supported and divanadium tris(sulphate) is conservatively assumed to have a potential to irritate the respiratory tract following repeated exposure. Nevertheless, no carcinogenicity, no pneumoconiosis and no other signs indicative of allergic inflammation have been reported for workers manufacturing divanadium tris(sulphate).

The registrant is aware that the National Toxicology Programme (NTP) in the US nominated tetra- and pentavalent vanadium forms(sodium metavanadate, NaVO3, CAS # 13718-26-8; and vanadium oxide sulphate, VOSO4, CAS # 27774-13-6), i.e. species present in drinking water and dietary supplements in 2007 (http://ntp.niehs.nih.gov/). A comprehensive characterisation via the oral route of exposure of

(i) chronic toxicity,

(ii) carcinogenicity, and 

(iii) multi-generation reproductive toxicity

is planned.

 

The NTP testing program began with sub-chronic drinking water and feed studies on VOSO4& NaVO3as follows:

- Genetic toxicology studies, i.e. the Salmonella gene mutation assays, with NaVO3 and VOSO4 - negative

-14 days with Harlan Sprague-Dawley rats and B6C3F1/N mice (dose: R&M: 0, 125, 250, 500, 1000, 2000 mg/L) - already completed

- 90days with Harlan Sprague-Dawley rats and B6C3F1/N mice (dose: R&M:: 0, 31.3, 62.5, 125, 250, or 500 ppm) - ongoing

- Perinatal dose-range finding study: gestation day 6 (GD 6) until postnatal day 42 (PND 42) with Harlan Sprague-Dawley rats - ongoing

- 28days immunotoxicity study (dosed-water) with female B6C3F1/N mice (dose:0, 31.3, 62.5, 125, 250, or 500 ppm) - ongoing

It can reasonably be anticipated that these studies will be of high quality and relevance, and thus will serve as a more robust basis than the current data base with all its shortcomings.In addition, repeated-dose inhalation toxicity studies (14, 28, and 90 days) with various vanadium substances are planned within the Vanadium Safety Readiness Safety Program. These studies will address issues for which to date equivocal or no data at all exist.Further information on these studies can be found in the attachments below.Only upon availability of the results from these studies, it will be possible to render a more meaningful decision on whether or not testing for repeated-dose toxicity is required. Therefore for the time being this data requirement should be waived in consideration of animal welfare.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
A number of studies are available where vanadium compounds were administered; however, they have involved different experimental approaches and designs as well as different dose regimens, and endpoints. For oral exposure, effects are more limited and the different experimental approaches lead to a variety of endpoints measured.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
reliable GLP-conform study with V2O5

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
Data of the repeated-dose toxicity via the dermal route are not available for any vanadium substance. Following the HERAG guidance for metals and metal salts (see section 7.1.2 of the technical dossier: dermal absorption), negligible percutaneous uptake based on minimal penetration, i.e. a dermal absorption rate in the range of maximally 0.1 - 1.0 %, can be anticipated. Dermal absorption in this order of magnitude is not considered to be “significant”. Thus, regarding repeated-dose toxicity of vanadium substances, the dermal exposure route is not expected to be the most relevant.

References:
EBRC (2007) HERAG fact sheet - Assessment of occupational dermal exposure and dermal absorption for metals and inorganic metal compounds, EBRC Consulting GmbH, Hannover, Germany, August 2007, 49 pages.

Justification for selection of repeated dose toxicity dermal - local effects endpoint:
Data of the repeated-dose toxicity via the dermal route are not available for any vanadium substance. Following the HERAG guidance for metals and metal salts (see section 7.1.2 of the technical dossier: dermal absorption), negligible percutaneous uptake based on minimal penetration, i.e. a dermal absorption rate in the range of maximally 0.1 - 1.0 %, can be anticipated. Dermal absorption in this order of magnitude is not considered to be “significant”. Thus, regarding repeated-dose toxicity of vanadium substances, the dermal exposure route is not expected to be the most relevant. However, divanadium tris(sulphate) has a potential for skin corrosion based on effects observed in the in vitro skin corrosion test.

References:
EBRC (2007) HERAG fact sheet - Assessment of occupational dermal exposure and dermal absorption for metals and inorganic metal compounds, EBRC Consulting GmbH, Hannover, Germany, August 2007, 49 pages.

Justification for classification or non-classification

Based on read-across of V2O5 data and in a conservative approach, local effects are considered relevant and divanadium tris(sulphate) is assumed to irritate the respiratory tract following repeated exposure. Therefore, divanadium tris(sulphate) (in the solid but not in the soluble form) meet the classification criteria for Specific target organ toxicity-repeated exposure - Category 1 according to Regulation (EC) No 1272/2008.