Pigments
Carbon black, the pigment in black News Ink, is safe. Carbon black is also used as in liquorice, paint, rubber, plastic and in the textiles that are used in everyday life. Carbon black could be harmful if inhaled as a dust but as it has been dispersed as paste in the other components of the ink and therefore the dust hazard issue has been negated.
Pigments in Colour News Inks are:
* C.I. Diarylide yellow, which is a non-hazardous organic compound that has a very low solubility and is not expected to cause problems in the environment (ECETOC has concluded that levels of organic substances in soils below 1 mg/kg are unlikely to adversely affect plant growth).
* C.I. 57 Rubine 4B Toner, which is calcium based and not hazardous.
* C.I. 15 Phthalocyanine blue, which is copper based, not hazardous and highly insoluble
Heavy metals
Heavy metals are not a danger in News Inks. No heavy metals (as defined in Australian Standard 1647, Part 3_1982) are added to black or process colour inks. Background levels are measured in parts per million, many times less than the Australian Standards for inks used in children’s' toys and colour comics. In fact, by 1977 all newspaper inks used in Australia were modified to "low toxicity" and lead was discontinued as a pigment base. Of course, trace contaminants are present everywhere in our environment and lead is no exception. But, tests have shown that News Inks comply with the presently accepted limits for lead of 100 ppm.
Oils
The amount of vegetable oil in inks varies. The great advantage of using vegetable oil is that it is a renewable resource, but the mineral oils used are highly refined and just as safe.
The mineral oil components of News Inks are safe and are not mutanogenic, carcinogenic or teratogenic. This is because after extreme refining very little remains of the polyaromatic substances found in the original mineral oils.
There are many methods to analyse the polyaromatic content of oil. IP 346 is the method used to determine whether an oil should be labelled as mutagenic or carcinogenic in the European Union. Mineral oils at the 3% IP346 level are clearly not carcinogenic, and oils used in News Inks are below this 3% level and therefore safe.
Chronic toxicity studies of mineral oils show that they do not represent a long-term danger to the aquatic environment. The oils are short terms or degradable and they are non-toxic. No classification is needed.
Highly refined mineral oils have an LD50 in rats of <5,000 mg / kg. This means that an 80 kg human, if they reacted similarly to rats, would require about 400 gm of oil, which would be more than a soft drink can of News Ink, for a toxic LD50 dose. Put another way you would need to consume more than 100 average weekday newspapers to achieve this toxic dose - that is about 12,000 pages of newsprint.
Ink formulations can vary, but the oil base is likely to be made up of:
Compounds
Volatile Organic Compounds (VOCs) can combine with other atmospheric pollutants to form smog. The high boiling point of New Inks, over 300 degrees, means that they release very low amounts of volatile substances. News Inks have a vapour pressure of less than 0.1 mm Hg @ 25 degrees, which means that they are more than twenty times below the threshold of 2 mm Hg required for classification as a VOC in the National Pollutant Inventory (NPI).
How much ink?
Of course very little ink is actually needed to make a newspaper. Approximately 8.2-8.5 kg of black ink and 4 kg of color ink is used per tonne of newsprint. This means that only a few grams of inks are on your average newspaper: a 300 grams newspaper might have less than 3.75 grams of ink (< 1.5%).