Toxic heavy metals are those which are of very high specific gravity than water and get accumulated in the body tissues as they are not able to get metabolized by the body. The effect of toxicity can lead towards severely affecting central nervous system, and also damaging the vital body organs such as blood composition, lungs, kidneys and liver etc.
There are various sources of contamination of these toxic heavy metals; and packaging items are one of them. All over the world, there are many regulations which regulate the safe limit of these toxic metals.
Further, it is important to note that some of the regulations such as Article 3 of The general food packaging safety 'framework' Regulation (EC) No 1935/2004 of the European Parliament (Materials and articles intended to come into contact with food) and the Indian Printing Ink for food packaging –code of practice IS-15495:2004 (Reaffirmed 2015) state that, the constituents of packaging materials should not "endanger human health". Toxic heavy metals fall under such constituents and should be regulated.
Printing Ink and Related Regulations:
The European Printing Ink Association (EuPIA), in its exclusion list suggests its members not to use pigment and colorants based on heavy metals such as antimony, arsenic, cadmium, chromium (VI), lead, mercury and selenium.
As per the Chinese standard QB 2930.2-2008 "Limits and determination method of certain toxic elements is printing ink Part 2: lead, mercury, cadmium, chromium (VI)", the sum of the concentration levels these four heavy metals shall not exceed 100 ppm.
There is a negative list present in the Annex-A of the Indian Printing Ink for food packaging –code of practice IS-15495:2004 (Reaffirmed 2015). As per this Annex-A, in case of pigment and dye based on heavy metal, the maximum permissible limit will be Antimony (Sb) < 60 ppm, Barium (Ba) < 1000ppm, Arsenic (As) < 25 ppm, Cadmium (Cd) < 75 ppm, Chromium (Cr VI) < 60 ppm, Lead (Pb) < 90 ppm and Mercury (Hg) < 60 ppm.
Council of Europe Resolution AP(89)1 applies to the use of colorants in plastic materials and articles coming into contact with food. This Resolution is provides the guideline for purity requirements for pigments including concentration limits for extractable heavy metals and others such as primary aromatic amines (PAA) and Polychlorinated Biphenyls (PCB). The heavy metal concentrations are Antimony (Sb) < 500 ppm, Barium (Ba) < 100ppm, Arsenic (As) < 100 ppm, Cadmium (Cd) < 100 ppm, Chromium (Cr VI) < 1000 ppm, Lead (Pb) < 100 ppm, Mercury (Hg) < 50 ppm and selenium (Se) < 100ppm.
Packaging and other special Regulations
The CONEG (Coalition of Northeastern Governors) regulation of the Unites States, of the USA and the directive on packaging and packaging waste such as 94/62/EC1 in Europe regulate the sum of the concentration levels of lead, cadmium, mercury and hexavalent chromium present in packaging or packaging components to a maximum level of 100 ppm.
The RoHS (Restriction of Hazardous Substances) regulation in the domain of electrical and electronic equipment, which comes under The European Directive 2011/65/EU and its amendments restricts the use of lead, Mercury, and hexavalent chromium to a level of 0.1% (w/w) and cadmium to a level of 0.01% (w/w)
Similarly, in China the Standards SJ/T 11363-2006 and GB/T 26572-2011 prohibit the amount of lead, mercury, hexavalent chromium to 0.1% max; and the amount of cadmium to 0.01% max. These standards are popularly known as China RoHS (Restriction of Hazardous Substances) or officially known as "Administrative Measure on the Control of Pollution Caused by Electronic Information Products".
The European legislation directive 2009/48/EC (replaced the former Directive 88/378/EEC) on Toy Safety is related to the safety of toys to be used for the children under fourteen years of age. The safe limits for heavy metals and organo-tin are divided into three categories of toys such as category I for Dry, Brittle, Powder-like or pliable material; Category II for Liquid or Sticky material and Category III for Scraped-off material. The ink formulators and converters should go through in detail before entering into this toy kind of toy printing business.
Determination of Heavy metal concentration:
Most of the recognized analytical labs use inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS) for determination of heavy metals in the samples. However, for a quick screening of these heavy metals, X-ray fluorescence spectrometer (XRF) method can be utilized.