Compliance Boundary
Regulatory frameworks demand that EN 13428 Heavy Metals restrict cumulative concentration levels of lead, cadmium, mercury, and hexavalent chromium within packaging materials to a maximum threshold of one hundred parts per million by weight. Certified paper and board converters calculate this aggregate sum across raw pulps, recycled content streams, wet-strength resins, and printing inks prior to market release. Exceeding this exact limit invalidates the environmental declaration of conformity required for commercial circulation inside member states.
Analytical laboratories employ atomic absorption spectrometry on digested substrate samples to verify compliance before converters dispatch commercial print runs.
Analytical Method
Spectrometric testing extracts target elements from representative cartonboard squares using acid digestion protocols defined under complementary harmonised standards. Sample preparation demands complete mineralisation of the fibrous matrix without volatilising volatile metallic compounds trapped inside mineral clay coatings or barrier layers. Technicians measure atomic absorption response curves against certified reference materials to establish baseline concentrations for each regulated element.
Print houses maintain these analytical records within their quality management systems to satisfy periodic supply chain audits.
Migration Risk
Residual trace quantities originating from recycled newspaper fibres or inorganic pigments can potentially transfer from secondary corrugated boxes into sensitive foodstuffs during ambient storage. Elevated moisture levels inside corrugated fluting accelerate ionic mobility across barrier coatings and increase total migration potential. Converters mitigate this operational risk by selecting virgin cellulose furnishes or demanding strict supplier declarations for all de-inked pulp fractions.
