Lead Chromate
Updated: April 2016
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Lead chromate (Plumbous chromate, Lead (II) chromate, PbCrO4, CAS no
7758-97-6) is a chemical compound that is a chromate of lead. It has a vivid
yellow color and occurs naturally as crocolite in Siberia, Hungary, and Brazil.
Lead chromate can be produced by a reaction of sodium chromate with lead
nitrate, or of lead monoxide with a chromic acid solution [ECHA].
Lead chromate is highly corrosive and is a strong oxidizing agent. It has an
extremely low level of solubility in water. [Atomistry].
Usage and Exposure
Lead chromate is used in the manufacture of industrial topcoat paints and
varnishes. It is also added to primer paints to provide coloring [HSE]. Lead
chromate is used in the production of highly resistant brightly colored paints
for products that require protection against corrosion such as vehicles, farm
equipment, boats and ships, civil engineering equipment, road signs and road
painting. It is also present in quick-drying enamels and floor paints [ECHA].
The use of lead chromate in paints has been curtailed in recent years to
reduce health hazards [IARC, Vol 87].
Lead chromate was also used in the manufacture of paints for conservation of
historic art objects, leather finishing mixtures, plastic masterbatches, and
finished plastics. It is also used in the manufacture of pyrotechnics, including
pyrotechnic delay and ignition compositions for ammunition and delay
detonators for the mining and demolition sectors [ECHA].
Routes of Exposure
Lead chromate can be absorbed into the body by inhalation of dust, mist or
spray during application, through direct skin or eye contact with paints, and by
ingestion [HSE].
Target Organs
Chromium (VI) compounds can produce noncancerous effects in several
target organs:
Respiratory system: Nasal and lung irritation, altered pulmonary
function
Gastrointestinal system: Irritation, ulceration and nonneoplastic lesions
of the stomach and small intestine
Hematological: microcytic, hypochromic anemia
Reproductive system: Effects on the male reproductive organs,
including decreased sperm count and histopathological changes to the
epididymis [ASTDR].
Health Hazards
The adverse effects on health associated with exposure to chromium and its
inorganic compounds vary according to valency state and water solubility.
Compounds of hexavalent chromium (chromium VI) include all chromates,
dichromates, and polychromates, which are the most hazardous.
Acute Effects
Contact with lead chromate substances can cause irritation of the eyes and
skin. Inhaling lead chromate can irritate the nose, throat and lungs. Exposure
can cause headaches, irritability, reduced memory, disturbed sleep and mood
and changes in personality. Contact can cause upset stomach, poor appetite,
weakness, and fatigue [NJ HEALTH].
Chronic Effects
Repeated or prolonged inhalation of lead chromate may cause asthma.
Repeated or prolonged contact of lead chromate with the skin may cause
dermatitis, chronic ulcers, and skin sensitization [CDC].
Direct contact and contamination of the eyes can result in irritation and
possible ulceration of the cornea [HSE].
Lead chromate may affect the blood, bone marrow, central nervous system,
peripheral nervous system, and kidneys, resulting in anemia, encephalopathy
(e.g., convulsions), peripheral nerve disease, abdominal cramps, and kidney
impairment.
Lead chromate may cause toxicity to human reproduction or development
[CDC].
There are few data on the effects of exposure to primer paints containing
chromium VI [HSE].
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Carcinogenicity
According to the IARC, there is sufficient evidence for carcinogenicity of
chromium (VI) compounds in humans. Chromium (VI) compounds can induce
lung cancer. Positive associations have also been observed between
exposure to Chromium (VI) compounds and cancer of the nose and nasal
sinuses.
Chromium (VI) compounds are carcinogenic to humans (Group 1) [IARC, Vol
100C].
The carcinogenic potency of Chromium (Cr (VI)) compounds differs
depending on their solubility. Lead chromate has a relatively low level of
solubility and has a lower carcinogenic potency as compared to compounds
with sparing or medium levels of solubility such as strontium, calcium, and
zinc chromates [Levy].
The Globally Harmonized System of Classification and Labeling of Chemicals
(GHS) classifies carcinogens into two categories.
Category 1 has two sub-categories:
Category 1A – Known human carcinogens (based upon human
evidence)
Category 1B – Presumed human carcinogens (based upon animal
evidence)
Category 2 – Suspected human carcinogens
The European Regulation on Classification, Labeling and Packaging of
Substances and Mixtures (CLP) uses the GHS classification of carcinogens,
and classifies Lead chromate as belonging to Category 1B - Presumed human
carcinogen [CLP, GHS].
References:
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ASTDR. Toxicological Profile for Chromium. 2012.
<http://www.atsdr.cdc.gov/toxprofiles/tp7.pdf>. Accessed 12/03/2016.
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Atomistry. Normal Lead Chromate, PbCrO4.
<http://lead.atomistry.com/normal_lead_chromate.html>. Accessed
10/01/2016.
-
CDC. Lead chromate.
<http://www.cdc.gov/niosh/ipcsneng/neng0003.html>. Accessed
09/01/2016.
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CLP - European Parliament Regulation No 1272/2008 on classification,
labeling and packaging of substances and mixtures. Annex VI:
Harmonised classification and labelling for certain hazardous
substances.
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ECHA (European Chemicals Agency). Background document for lead
chromate. <http://echa.europa.eu/documents/10162/13640/axivbd_lead-chromate_20101217_en.pdf>. Accessed 09/01/2016.
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HSE. Chromate primer paints.
<http://www.hse.gov.uk/pubns/eis32.pdf>. Accessed 03/01/2016.
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IARC. Volume 87. Inorganic and Organic Lead Compounds. 2006
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IARC monographs on the Evaluation of Carcinogenic Risks to Human,
Vol 100C, Arsenic, Metals, Fibres and Dusts, IARC Scientific
Publications, Lyon, 2012.
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GHS. Globally Harmonized System of Classification and Labelling of
Chemicals (GHS). Sixth revised edition. UN 2015.
<http://www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/ghs_rev0
6/English/03e_part3.pdf>. Accessed 13/03/2016.
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Levy L.S., Martin P.A, Bidstrup P.L.: Investigation of the potential
carcinogenicity of a range of chromium containing materials on rat lung.
British Journal of Industrial Medicine 1986; 43:243-256.
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NJ HEALTH (New Jersey Department of Health). Lead Chromate.
<http://nj.gov/health/eoh/rtkweb/documents/fs/1102.pdf>. Accessed
03/01/2016
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