Harper Emma, Cunningham Eoin, Connolly Lisa
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom.
School of Mechanical and Aerospace Engineering, Queen's University Belfast, Belfast, United Kingdom.
Front Toxicol. 2022 Sep 20;4:936014. doi: 10.3389/ftox.2022.936014. eCollection 2022.
Petroleum-based polymers traditionally used for plastic packaging production have been shown to leach dangerous chemicals such as bisphenol-A (BPA). Bio-based polymers are potentially safer alternatives, and many can be sustainably sourced from waste streams in the food industry. This study assesses bio-based polymers undergoing food packaging development for migration of endocrine disrupting leachates at the level of estrogen, androgen and progestagen nuclear receptor transcriptional activity. Reporter gene assays were coupled with migration testing, performed using standardised test conditions for storage and temperature. Test samples include nine bio-based polymers and four inorganic waste additives mixed with a traditional petroleum-based polymer, polypropylene. Thermoplastic starch material, polybutylene succinate, polycaprolactone, polybutylene adipate terephthalate (PBAT), two polylactic acid (PLA)/PBAT blends, polyhydroxybutyrate (PHB) and eggshell/polypropylene (10:90) presented no significant reduction in metabolic activity or hormonal activity under any test condition. Polypropylene (PP) presented no hormonal activity. Metabolic activity was reduced in the estrogen responsive cell line after 10 days migration testing of eggshell/polypropylene (0.1:99.9) in MeOH at 40°C, and PP in MeOH and dH0. Estrogenic agonist activity was observed after 10 days in poultry litter ash/polypropylene (10:90) in MeOH at 20°C and 40°C, poultry feather based polymer in MeOH and dHO at 40°C, and eggshell/polypropylene (40:60) and PLA in dHO at 40°C. Activity was within a range of 0.26-0.50 ng 17-estradiol equivalents per ml, equating to an estrogenic potency of 3-∼2800 times less than the estrogenic leachate BPA. Poultry litter ash/polypropylene (10:90) in MeOH for 10 days presented estrogenic activity at 20°C and 40°C within the above range and anti-androgenic activity at 40°C. Progestagenic activity was not observed for any of the compounds under any test condition. Interestingly, lower concentrations of eggshell or PP may eliminate eggshell estrogenicity and PP toxicity. Alternatively eggshell may bind and eliminate the toxic elements of PP. Similarly, PLA estrogenic activity was removed in both PLA/PBAT blends. This study demonstrates the benefits of bioassay guidance in the development of safer and sustainable packaging alternatives to petroleum-based plastics. Manipulating the types of additives and their formulations alongside toxicological testing may further improve safety aspects.
传统上用于塑料包装生产的石油基聚合物已被证明会渗出双酚A（BPA）等危险化学品。生物基聚合物是潜在更安全的替代品，许多生物基聚合物可以从食品工业的废物流中可持续获取。本研究评估了正在开发用于食品包装的生物基聚合物，以检测其在雌激素、雄激素和孕激素核受体转录活性水平上内分泌干扰性渗滤液的迁移情况。报告基因检测与迁移测试相结合，迁移测试采用标准化的储存和温度测试条件。测试样品包括九种生物基聚合物和四种无机废物添加剂，它们与传统石油基聚合物聚丙烯混合。热塑性淀粉材料、聚丁二酸丁二醇酯、聚己内酯、聚己二酸/对苯二甲酸丁二醇酯（PBAT）、两种聚乳酸（PLA）/PBAT共混物、聚羟基丁酸酯（PHB）以及蛋壳/聚丙烯（10:90）在任何测试条件下代谢活性或激素活性均未出现显著降低。聚丙烯（PP）未表现出激素活性。在40°C下于甲醇中对蛋壳/聚丙烯（0.1:99.9）以及在甲醇和去离子水中对PP进行10天迁移测试后，雌激素反应细胞系中的代谢活性降低。在20°C和40°C下于甲醇中对家禽粪便灰/聚丙烯（10:90）、在40°C下于甲醇和去离子水中对家禽羽毛基聚合物进行10天测试后，以及在40°C下于去离子水中对蛋壳/聚丙烯（40:60）和PLA进行测试后，均观察到雌激素激动剂活性。活性范围为每毫升0.26 - 0.50纳克17-β-雌二醇当量，相当于雌激素效力比雌激素渗滤液BPA低3至约2800倍。在20°C和40°C下于甲醇中对家禽粪便灰/聚丙烯（10:90）进行10天测试呈现上述范围内的雌激素活性，在40°C下呈现抗雄激素活性。在任何测试条件下，未观察到任何化合物具有孕激素活性。有趣的是，较低浓度的蛋壳或PP可能消除蛋壳的雌激素性和PP的毒性。或者，蛋壳可能结合并消除PP的有毒元素。同样，在两种PLA/PBAT共混物中PLA的雌激素活性均被消除。本研究证明了生物测定指导在开发比石油基塑料更安全、更可持续的包装替代品方面的益处。在毒理学测试的同时，控制添加剂的类型及其配方可能会进一步提高安全性。
