Toxic pigment

Pigments and dyes provide paint and ink colors. Many highly toxic pigments, such as copper acetate (blue-green), arsenic trisulfide (yellow), and mercury II iodide (red), are no longer used. However, other hazardous pigment compounds, such as lead carbonate, mercury II sulfide, and cadmium sulfide, are still used today. These compounds present a danger to those artists who use their mouths to make a brush more pointed. 

Further examples of the use of INADEQUATE in biosynthetic studies include biosynthesis of naphthylisoquinoline alkaloids,69 blepharismin C, toxic pigments of the ciliate Blepharisma japonicum,70 lambertellols A and B and lambertellin and metabolites of Ascomycete fungi.71... 

Since Brockman s discovery of toxic pigments produced by Streptomyces in the early 1960s [8], thousands of new daunomycin derivatives have been obtained, either by synthesis involving glycosidic bond reassembly or by directed biogenesis. Early discussions on structure-activity relationships are presented in a fundamental account elaborated by Arcamone [3,92]. Over the years, as the methods for evaluation of drug candidates became more so-... 

A white non-reactive and non-toxic pigment that provides the greatest hiding power of all white pigments. 

Other toxic pigments which are found in old paints may contain ... 

Lead pigments are commonly used in paints, although less toxic pigments are presently used preferentially. Red lead (minimum) is used extensively in the painting of structural steel, and lead chromate is used as a yellow pigment (see Table 1). At... 

Iron oxides, which were undoubtedly components of these prehistoric paints, still find application today as low-cost, low-toxicity pigments in paint, plastics, rubbers and cosmetics. The three main colours available are red (haematite-, Fe203), yellow (goethite FeO.OH) and black (magnetite-, Fe304), and other colours can be produced by blending these three. The oxides are generally prepared by precipitation from aqueous solution ... 

Daylight fluorescent pigments (qv) are considered to be nontoxic. Since they are combinations of polymers and dyestuffs, the combined effect of the ingredients must be taken into account when considering the net toxic effect of these materials. Table 5 gives results of laboratory animal toxicity tests of standard modified melamine—formaldehyde-type pigments, the Day-Glo A Series, and the products recommended for plastic mol ding, Day-Glo Z-series. 

In heavy-metal analysis of the same pigments, metals found were present in only trace amounts. The data Hsted place the products tested in the category of nontoxic materials. The Radiant Color Co. has conducted toxicity tests on its own products similar to the A-Series and has found them to be nontoxic. Heavy metals were found only in trace amounts in these tests. 

AppHcations of mercury include use in batteries (qv), chlorine and caustic soda manufacture (see Alkali and chlorine products), pigments (see Pigments, inorganic), light switches, electric lighting, thermostats, dental repair (see Dental materials), and preservative formulations for paints (qv) (1—3). As of the end of the twentieth century, however, increased awareness of and concern for mercury toxicity has resulted in both voluntary and regulatory reduction of mercury usage (see also Mercury compounds). 

Coatings, Paints, and Pigments. Various slightly soluble molybdates, such as those of zinc, calcium, and strontium, provide long-term corrosion control as undercoatings on ferrous metals (90—92). The mechanism of action presumably involves the slow release of molybdate ion, which forms an insoluble ferric molybdate protective layer. This layer is insoluble in neutral or basic solution. A primary impetus for the use of molybdenum, generally in place of chromium, is the lower toxicity of the molybdenum compound. 

Nltropropane. As much as 9100 t of 2-nitropropane once were consumed for use in coatings annually. Concern about toxicity and a general movement to low volatile organic compound (VOC) coatings have resulted in almost the complete disappearance of this use for 2-nitropropane. However, derivatives such as 2-meth5l-2-nitro-l-propanol (used in tire cord adhesive) and 2-amino-2-methyl-l-propanol (a pigment dispersant and buffer), have served as an outlet for 2-nitropropane production. 

Pigments and Extenders. Pigments are selected for use in house paints based on thek appearance and performance quaUties. Appearance includes color and opacifying abiUty. Performance quaUties include ultraviolet light resistance, fade resistance, exterior weatherabiUty, chemical resistance, as well as particle size and shape. Toxicity profiles and safety and health related properties are also important criteria in pigment selection. 

Solvents. Solvents in house paints serve several essential purposes. They keep the binder dispersed or dissolved and the pigments dispersed in an easy-to-use state. Solvents allow the paint to be appHed in the correct thickness and uniformity, and evaporate from the paint film after the paint is apphed. Solvent choice is limited mainly to a solvent that is compatible with the binder system and that has the desked evaporation rate and toxicity profile. The volatility or evaporation rate of a solvent determines to a large extent the open-time and dry-time properties of a paint (6). 

Pigments contribute to the enjoyment and beauty of the world. To assure the future of inorganic pigments, research efforts are directed toward the development of environmentally acceptable pigments, pigments that when produced under weU-controUed conditions do not release any toxic materials into the environment whether during production, use, or disposal. 

NPIRI Raiv Materials Data Handbook, Vol. 4, Pigments, Francis MacDonald Siaclair Memorial Laboratory 7, Lehigh University, Bethlehem, Pa., 1983. K. H. Leist, Toxicity of Pigments NIFMB Symposium, Stockholm, 1980. 

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