Short- and medium-chain chlorinated paraffins in plastic animal feed packaging and factors affect their migration into animal feed

Abstract

Chlorinated paraffins (CPs) are used as plasticizers and flame retardants in plastics. Plastic packaging containing CPs is widely used for storage of animal feed, which can become contaminated by CPs that migrate into the feed. In the present study, 31 commercial animal feed packaging samples made of polypropylene (PP) or polyethylene (PE) were collected from animal feed manufacturers in China. The mean concentrations of short-chain chlorinated paraffins (SCCPs) in the PP and PE samples were 60.0 and 54.5 μg/g, respectively. The medium-chain chlorinated paraffin (MCCP) mean concentrations in the PP and PE samples were 62.7 and 9.23 μg/g, respectively. The carbon congener group profiles of SCCPs and MCCPs in the samples were different. The dominant SCCP and MCCP chlorine congener groups in all the samples were Cl6–7 and Cl6–8, respectively. Time and temperature influenced the migration of CPs from packaging into animal feed. As the time or temperature increased, the CP concentrations in the animal feed increased but the congener group profiles of the SCCPs and MCCPs in the animal feed did not change. To reduce contamination of animal feed by CPs, it is necessary to restrict the use of CPs in animal feed packaging.