奈米微粒危害分級管理適用性之探討——以奈米氧化鋅為例

Investigation of the Applicability of Nanoparticle Control Banding-Using Zinc Oxide Nanoparticle as an Example

近年來奈米材料的危害分級方式乃因受限於現階段奈米材料毒理資訊缺乏，故以推論的方式將原始粉體增加一級訂定，然而需更多的毒性及危害資料來證實此方法之適用性。目前斑馬魚被ISO列為建議的奈米材料毒性篩選動物實驗模式，並期待能藉此獲得更充足的生物毒性資料作為奈米材料毒性效應之危害分級管理之依據。本研究選用在日常生活上已廣泛被應用且可能具有生物毒性之奈米氧化鋅與一般粉體氧化鋅進行比較，以斑馬魚胚胎及稚魚模式進行體內毒性試驗，並區分奈米與一般粉體氧化鋅之毒性差別，最後嘗試將我們的研究結果應用在奈米物質危害分級管理中。結果發現斑馬魚胚胎及稚魚暴露在奈米與一般粉體氧化鋅材料其LC50（50% lethal concentration）與EC50（50% effective concentration）之值前者大致上較後者低。初步根據急性水生毒性危害物質分類標準，氧化鋅奈米材料隸屬於“危害級別1＂，而一般粉體材料為“危害級別2＂，顯示奈米材料在急毒性危害分級較其原始粉體危害級別更高，因此初步證實奈米氧化鋅在危害等級分級上依其原始粉體提高分級並加以進行管理是合理的推論。

As the information pertaining to nanomaterial toxicology is currently inadequate, we’ve used to perform hazard ranking of the selected nanomaterials (NMs) in the recent years by extrapolating it according to the information form their bulk counterparts, and formulated it by considering the hazard levels of these nanomaterials as being one magnitude higher than those of the bulk counterparts. However, it’s still necessary to provide more toxicology and chemical hazard information to verify the feasibility of such strategy. Currently, zebrafish has been recommended by ISO as the NMs toxicity screening animal model, and hopefully we may obtain more toxicology data to sufficiently serve as the basis of NMs-specific hazard banding. In our studies, we chose nano zinc oxides, which have been widely applied in daily life and display toxic potential, as the model nanomaterial, and compared its toxicity with that of the counterpart bulk powers by using zebrafish embryos and larvae respectively. We attempted to make our results applicable for NMs-specific hazard ranking and control banding. Our results showed that the LC50 (50% lethal concentration) and EC50 (50% effective concentration) values of nano zinc oxides are comparatively lower than those of bulk zinc oxides. According to the acute aquatic toxicity classification criteria, we recommended nano zinc oxides as 'hazard ranking one' and bulk zinc oxides as ' hazard ranking two'. In this regard, this suggest that the NMs have to be assigned to a higher hazard band, in terms of acute toxicity, as compared to the bulk powder counterparts. We preliminarily confirmed the feasibility of using toxicology information of bulk zinc oxides to carry out hazard banding of nano zinc oxides and ranking them by considering them as at least one magnitude higher. As a result, nano zinc oxides must be subjected to the management plan.