Toxicology and Environmental Aspects

The Berufsgenossenschaft der Chemischen Industrie (Germany) has recommended that all iron oxide pigments should be classified as inert fine dusts with an MAK value of 6 mg/m3. This is the highest value proposed for fine dusts. 

Iron oxide pigments produced from pure starting materials may be used as colorants for food and pharmaceutical products [3.42], Synthetic iron oxides do not contain crystalline silica and therefore are not considered to be toxic, even under strict Californian regulations. 

Some iron oxide pigments have a limited stability on heating. Red iron oxide is stable up to 1200 °C in air. In the presence of oxygen, black iron oxide changes into 

All synthetic iron oxides possess good tinting strength and excellent hiding power. They are also lightfast and resistant to alkalis. These properties are responsible for their versatility. The principle areas of use are shown in Table 24. 

Natural rubber can only be colored with iron oxides that contain very low levels of copper and manganese (Cu 0.005%, Mn 0.02%). Synthetic rubber is less sensitive. 

The low tendency of migration and bleeding is of great advantage in plastics. Pure grades of iron oxide pigments are allowed for coloring of plastic articles for food and commodities [3.51]. 

The use of iron oxide as a polishing medium for plate glass manufacture has decreased sharply with the arrival of the float glass technology. 

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This symposium addressed several important issues in bromine chemistry. A major part has been devoted to stereochemistry and mechanism of electrophilic bromination of olefins. Other topics included new selective methods of bromination and oxybromination, brominations in presence of solid supports and catalysts, organobromine compounds as synthons, recent developments in brominated fire retardants and toxicological and environmental aspects of brominated compounds. 

According to data available so far, synthetic juvenoids are only slightly toxic to mammals, birds and hsh, their acute oral ld,o for mice being higher than 4000 mg/kg. Therefore, their use should have considerable advantages with regard to human toxicological and environmental aspects compared to conventional... 

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