Chlorinated paraffins in food contact materials made of rubber from the German market

Abstract

Chlorinated paraffins (CPs), also known as polychlorinated alkanes (PCA), are a very complex class of polyhalogenated compounds currently produced in unmatchable amounts for different industrial uses. Short-chain CPs (SCCPs; C10- to C13-CPs) are listed as POPs in the Stockholm Convention and medium-chain CPs (MCCPs; C14- to C17-CPs) are proposed for listing. Here, we investigated the presence of SCCPs and MCCPs in 21 rubber samples used as food contact materials from the German market. For this purpose, an analytical method was developed which consisted of (i) freezing and (ii) grounding of the material, (iii) removal of oligomers by adsorption chromatography, (iv) matrix destruction with sulfuric acid, and (v) GC/ECNI-MS screening and quantification. Three of the rubber samples were found to contain predominantly MCCPs at 69, 113,000 and 341,000 mg/kg. The highest amount (corresponding with 34 weight-% CPs) was determined in one rubber band sample used to bundle a bunch of spring onions. A very high CP content of >300,000 mg/kg in this rubber band sample was confirmed by quantitative 1H NMR (qNMR) analysis. This rubber material was in direct contact with the onions and leaching of CPs into the food cannot be excluded. Even more, micro-abrasions of rubber could be unintentionally swallowed by the consumer and this CP exposure could be higher than the current CP intake via food.

Keywords

• Chlorinated paraffin
• Polychlorinated alkanes
• Food contact material
• Rubber
• GC/ECNI-MS
• NMR