Monitoring of Polymer Type and Plastic Additives in Coating Film of Beer Cans From 16 Countries

Abstract

Plastic debris has gained attention as anthropogenic waste in the environment, but less concerned given to metal waste despite its high abundance in aquatic environment. Metal packaging, such as can, utilizes polymeric coating films as barrier between metals and products which leads to be potential source of microplastic pollution. In this study, 27 beer cans from 16 countries for both body and lid parts as well as inside and outside layers were investigated. Despite the country’s origin, epoxy resin was the major polymeric coating used in all beer cans for lid (inside and outside) and body (inside). Whereas poly(1,2-butanediol isophthalate) was frequently used for outside layer of can body. Marketing countries turned out not specify the amount of additives used in can. DEHP and BHT were detected in almost all samples with the highest concentration of 5,300 ng/g and 520 ng/g. Despite its lower detection frequency, DOA was detected as high as 9,600 ng/g in Belgian beer can. Although being broken down, additives concentration in one environmental sample was found to be one to two orders of magnitude higher compared to the new can. This result suggests that metal debris may become source of microplastic and additives in the environment.