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North Carolina Department of Environment and Natural Resources Division of Air Quality

Risk Analysis Background Documentation

AAL Recommendation (1-11-91)

THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL

January 11, 1991

Gladys VanPelt, PhD Chair, Air Quality Committee Environmental Management Commission Department of Environment, Health, and Natural Resources P.O. Box 27687 Raleigh, NC 27611-7687

Dear Dr. VanPelt:

Re: Acceptable Ambient Levels for Compounds In its meeting on November 15, 1990, the Scientific Advisory Board on Toxic Air Pollutants unanimously adopted a motion to recommend to the Environmental Management Commission that the following listed Acceptable Ambient Levels for chromium compounds be adopted by the Commission: COMPOUND EFFECT AAL (mg/m3) Bioavailable pigments human cancer 8.3 X 10-8 salts of: Calcium Strontium

Soluble chromate compounds nose ulceration 6.2 X 10-4 Chromic acid Chromate and dichromate salts of: Potassium Sodium Ammonium

Lithium chromate none reported none

North Carolina Department of Environment and Natural Resources Division of Air Quality

The recommended AAL's for chromate and dichromate salts of calcium and strontium are unchanged from those listed in part .1104(b) of the current regulation.

The current regulation does not list chromate compounds of zinc. The new AAL recommended by the Board reflects the recognition of chromate salts of zinc as human carcinogens.

The compounds listed above in the category "soluble chromate compounds" are suspect carcinogens; the AAL calculated for this classification of carcinogens is more lenient than that for their known effect in nose ulceration. Adoption of the more stringent AAL based on nose ulceration is recommended.

No effect for exposure to chromate salts of lithium has been identified; the Board recommends that lithium salts be removed from the AAL list.

Documentation of the Board's recommendations was prepared by Woodhall Stopford, MD. A copy of Dr. Stopford's written review is appended to this letter.

Sincerely yours,

Robert L. Harris, PhD Chair, Scientific Advisory Board on Toxic Air Pollutants

Enclosure cc: Members, Scientific Advisory Board on Toxic Air Pollutants Members, EMC Air Quality Committee Director, DEM Director, Air Quality Section, DEM W. Stopford, MD November 11, 1990

North Carolina Department of Environment and Natural Resources Division of Air Quality

Chromium Carcinogenicity

Detoxification of Chromate Cr+3 passes through biologic membranes a rate 3 orders of magnitude less than Cr+6. Cr+3 is not mutagenic or carcinogenic. Intracellular reduction of Cr+6 is required in order to see a mutagenic effect. Reduction capacity in bronchial epithelial cell microsomes is similar between rodents and man. Reduction of Cr+6 prior to cellular uptake prevents carcinogenic risk. Reduction occurs in saliva (>10000 mcg reductive capacity/day (Petrilli & de Flora '87)), epithelial lining fluid, and alveolar macrophages (several thousand mcg reductive capacity/day (Hathaway '86, Petrilli, et al. '85)). These authors consider this detoxification to be a threshold for the mutagenic and carcinogenic effects of chromate ion.

When reductive pathways are saturated, either by excessive dose or by microenvironmentally high levels as found in association with highly bioavailable chromate pigment particles (ones slightly soluble in water and soluble in weak acids), then a carcinogenic effect can be seen. Steinhoff, et al. (1986) demonstrated this effect: rats given 1.25 mg/wk soluble chromate i.t. divided in daily doses did not develop pulmonary tumors. When the same weekly dose was given once a week (presumably saturating the detoxification system), 20 of 80 animals developed tumors.

NOEL for Soluble Chromates The ACGIH TLV (50 mcg/m3) for chromates is set to prevent nasal irritation with an LOEL noted of 60 mcg/m3. Lindberg, et al.('83), in a study published since the last action of ACGIH, investigated clinical effects in workers exposed to Cr+6 in the chrome plating industry. All individuals with nasal septal perforations or ulcers had exposures in excess of 20 mcg/m3 while working over plating bathes. Workers who did not work over the bathes had neither change. The exposures of these latter workers were always <2 mcg/m3. However.- samples were collected on fiberglass filters and stored prior to alkaline elution and analysis. Although the authors did not find any difference between this method and an impinger sampling technique, the NIOSH chromate analytical method, utilizing fiberglass filters as a collecting medium, has been shown to be associated with in excess of 90% reduction of chromate on the filter. Once reduced, aqueous washing will not effectively remove the chromium: analyses will be erroneously low.

North Carolina Department of Environment and Natural Resources Division of Air Quality

November 11, 1990 W. Stopford, MD

Solubility of Chromates in Water

Compound Solubility (a/1) Category (IARC) chromic acid 625 soluble ammonium chromate 890 soluble 629 soluble 873 soluble potassium dichromate 49-1020 soluble 2380 soluble ammonium dichromate 308-890 soluble zinc chromate --- insoluble strontium chromate 1.2-30 slightly soluble calcium chromate 163 slightly soluble lead chromate --- insoluble 0.004 insoluble lithium chromate ------

North Carolina Department of Environment and Natural Resources Division of Air Quality

Highly Bioavailable Chromate Pigments Animal Studies:

Intratracheal: Compound Incidence Significance Reference calcium chromate 25/100 * Levy '86 calcium chromate 8/100 Laskin, '70 8/100 * Levy '86 strontium chromate 43/99 * " “ 62/99 * Levy '86 zinc chromate 5/100 * " zinc chromate 3/100 * Levy '86 “ 31/62 * Steffee '65 control 0/400 Levy '86 Inhalation: calcium chromate 14/136 * Nettesheim '71 control 5/136 "

Human Studies: mixed chromates 37/1000 lung Ca Mancusco '75 mixed chromates 29 (RR lung Ca) Brinton '52 ferrochromium 7/3.1 lung Ca (O/E) Langard '80 (mixed exposure)

* p <0.05 NS p > 0.05

Risk Assessments: Study Agency 10-6 Risk (mg/m3) Mancuso '75 EPA-CAG 8.3 x 10-8 Langard, '80 NRC 7 x 10-8 Nettesheim, '71 NRC (MLE) 5 x 10-5

Soluble Chromates Animal Studies:

Intratracheal:

North Carolina Department of Environment and Natural Resources Division of Air Quality

Compound Incidence Significance Reference chromic acid 1/100 ns Levy '86 “ 2/100 ns " “ 0/100 Laskin '70 chromic oxide 0/100 ns Levy '86 chromic trioxide 0/100 Laskin '70 sodium dichromate dihydrate 0/100 ns Levy '86 sodium dichromate 1/99 ns " “ (5x/wk) 0/80 Steinhoff '86 “ (lx/wk) 20/80 " sodium chromate 0/100 ns Levy '86 chromic chloride hexahydrate 0/100 ns " control 0/400 Inhalation: sodium dichromate 3/55 * Glaser '86 controls 0/37 “

North Carolina Department of Environment and Natural Resources Division of Air Quality

Human Studies: soluble chromates 1.02 (SMR) Davies '90 (chromate production) * p <0.05 NS p > 0.05 Risk Assessments: Study Agency 10 5 Risk (mg/m3) Glaser, et al. '86 EPA-CAG 2 x 10-° Glaser, et al. '86 NCATC 4.1 x 10-3

Low Bioavailable Chromate Pigments Animal Studies:

Intratracheal: Compound Incidence Significance Reference lead chromate 1/100 ns Levy '86 “ 1/100 ns " “ 1/98 ns " “ 0/100 ns " “ 0/100 ns “ “ 0/100 ns " barium chromate 0/101 ns " zinc tetraoxy chromate 1/100 ns " control 0/400 "

Human Studies: lead chromate/soluble chromates 4/5.07 (O/E) ns Davies '84

* p <0.05 NS p > 0.05

IARC Stance (Suppl 4, 1980): "Calcium chromate is carcinogenic in rats after its administration by several routes, including intrabronchial implantation. Chromium chromate, strontium chromate and zinc chromate produce local sarcomas in rats at the sites of their application. Inadequate evidence was available for the carcinogenicity in mice and rats of barium chromate, lead chromate, chromic acetate, sodium dichromate and chromium carbonyl".

North Carolina Department of Environment and Natural Resources Division of Air Quality

IARC Stance (v.49, 1990) "There is sufficient evidence in experimental animals for the carcinogenicity of calcium chromate, zinc chromates, strontium chromate and lead chromates. There is limited evidence in experimental animals for the carcinogenicity of chromium trioxide (chromic acid) and sodium dichromate. There is inadequate evidence in experimental animals for the carcinogenicity of metallic chromium, barium chromate and chromium[III] compounds."

Lead chromates produce injection site sarcomas with IM or subcutaneous injections (in some experiments). These studies (Maltoni '74; Furst '76) were first evaluated by IARC in 1990.

Proposed AALs for Chromates Compound Effect AAL (mg/m3) Bioavailable pigments cancer 8.3 x 10-8** (calcium, strontium, zinc*) Soluble chromates cancer 4.1 x 10-3 (chromic acid; potassium, nose ulceration 6.2 x 104** sodium, and ammonium salts) lithium chromate none no AAL** *add to AAL list **recommended AAL

References Brinton, HP, et al. (1952) Morbidity and mortality experience among chromate workers. Public Health Rep. 67: 835-847.

Davies, JM (1984) Lung cancer mortality among workers making lead chromate and zinc chromate pigments at three English factories. Br. J. Ind. Med. 41: 158-169.

Davies, JM, DF Easton, PL Bidstrup (1990) Mortality from respiratory cancers and other causes in United Kingdom Chromate Production Workers (manuscript)

Furst, A, et al (1976) Tumorigenic activity of lead chromate. Cancer Res. 36:1779-1783.

Glaser, U, et al. (1986) Carcinogenicity of sodium dichromate and chromium (VI/III) oxide aerosols inhaled by male Wistar rats. Toxicology 42:219-232.

North Carolina Department of Environment and Natural Resources Division of Air Quality

Hathaway, JA (1989). Role of epidemiologic studies in evaluating the carcinogenicity of chromium compounds. Sci. Total Environ. 86: 169-179.

Langard, S, et al. (1980) Incidence of cancer among ferrochromium and ferrosilicon workers. Br. J. Ind. Med. 37:114-120.

Laskin, S, et al. (1970) Studies in pulmonary carcinogenesis. In: Hanna, MG, Nettesheim, P, Gilbert, JR (eds.). Inhalation Carcinogenesis. US Atomic Energy Commission. pp.321-351.

Levy, LS, PA Martin, PL Bidstrup (1986) Investigation of the potential carcinogenicity of a range of chromium containing materials in rat lung. Br. J. Ind. Med. 43: 243-256.

Lindberg, E, G Hedenstierna (1983) Chrome plating: symptoms, findings in the upper airways, and effects on lung function. Arch. Environ. Hlth. 38: 367-374.

Maltoni, C (1974) Occupational carcinogenesis. Excerpta Med. Int. Congr. Ser. 322:19-26.

Maltoni, C, et al (1982) Experimental approach to the assessment of the carcinogenic risk of industrial inorganic pigments. Adv. Mod. Environ. Toxicol. 2:77-92.

Mancuso, TF (1975). International Conference on Heavy Metals in the

Nettesheim, P, et al. (1971) Effect of calcium chromate dust, influenza virus and 100 R whole-body X radiation on lung tumor incidence in mice. JNCI 47:1129-1138.

Petrilli, FL, et al. (1986) Metabolic reduction of chromium by alveolar macrophages and its relationship to cigarette smoke. J. Clin. Invest. 77: 1917-1924.

Petrilli, FL, S de Flora (1987) Letter: Carcinogenicity of chromium and its salts. Br. J. Ind. Med. 44: 355.

Steffee, CF, AM Baetjer (1965) Histopathologic effects of chromate chemicals. Report of studies in rabbits, guinea pigs, rats and mice. Arch. Environ. Hlth. 11: 66-75.

North Carolina Department of Environment and Natural Resources Division of Air Quality

Steinhoff, D, et al. (1986) Carcinogenicity studies with sodium dichromate in animals. In: DM. Serrono (ed.) Chromium Symposium 1986: an Update. Pittsburgh: IHF. pp. 131-155.