塑膠微粒與人體健康

Microplastics and Human Health

塑膠微粒是小於5毫米的塑膠顆粒，主要是塑膠產品裂解形成。塑膠微粒存在於大氣，海水及淡水，可經由呼吸道及腸胃道吸收。最近研究發現，食物塑膠容器及包裝材料遇到高溫時，會釋出10億以上的微米及奈米塑膠微粒。毒理研究顯示，塑膠微粒可以被吸收分佈到其他器官，同時引發全身性的毒性。有趣的是，微米微粒比較不容易被吸收，但是對腸道菌群的影響較大，可能經由腸道菌群失調，危害健康。人體研究顯示，身體的許多器官都可以檢測到塑膠微粒，不過因為暴露評估沒有到位，特別是次微米與奈米粒徑的微粒，所以流行病學研究報告比較少。目前研究顯示，人體暴露到相當數目的塑膠微粒，健康效應需要進一步探討，同時採取必要的預警措施，避免潛在危害。

Microplastics are plastic fragments smaller than 5 mm, which are resulted from the degradation of plastic products. Microplastics are found in the air, oceans and ground water, and they are absorbed through respiratory and gastrointestinal tracts. Recent studies showed that billions of micro- and nanoplastics were released from food contact plastics. Toxicological studies have demonstrated that microplastics could be absorbed and distributed to organs, then resulted in the systemic toxicities. It is interesting that microplastics greater than micrometers are less likely to be absorbed, but cause greater effects on gut microbiota, which may subsequently cause toxicities in some organs. Microplastics have been detected in many human organs. However, epidemiological studies are limited, because of the inadequate exposure assessment, particularly for nanoplastics. In summary, current researches have demonstrated that humans are exposed to large amount of microplastics. It is warrant to pursue further studies in health effects of microplastics. Meanwhile precautionary principles must be adopted to prevent potential health effects from exposure to microplastics.