Abstract
摘要：奈米二氧化鉛(nPbO2)為用於工業或廢水處理程序的新興奈米材料，也是使用加氯消毒之自來水系統中新發現的鉛管或鉛材(如含鉛水龍頭)腐蝕產物。nPbO2可因流速改變自管壁脫附；當水質改變或更換消毒劑時，更會加速nPbO2釋放出鉛離子。目前各大城市（包括台灣）皆有相當比例的鉛管或鉛材殘留，由於全面汰換自來水系統中之含鉛設備需要長時間，鉛污染飲用水的問題因而受到全世界的重視。鉛為有毒重金屬，其致毒機制多元而複雜；然而nPbO2的生物毒性及對人體健康與生態安全的衝擊目前所知有限。本計畫旨在利用青鱂魚及人類細胞為模式生物來探討nPbO2的毒性機制與危害風險等議題。第一年將利用奈米分析化學技術，探討nPbO2於暴露溶液中的物化行為變化、生物可利用性及生物累積潛能；第二年將結合分子生物學與細胞培養技術，探討不同鉛物種(如不同粒徑顆粒及鉛離子)對生物體可能誘導之基因毒性、氧化傷害或神經毒性等效應；第三年將探討nPbO2於環境水域的宿命、生物有效性與奈米生態毒理議題。本計畫為一項結合基礎研究與實際應用的跨領域研究，研究成果將可提供學術界及規範單位一套研究奈米毒理學的整合性方法，並有助於瞭解nPbO2對人體健康及水域安全的衝擊，以加速各項規範水中鉛汙染政策的推動。
Abstract: Nanoscale lead dioxide (nPbO2(s)) is an attractive nanomaterial with high potential being used in industrial manufactures and electrochemical wastewater treatment processes. It is also a newly identified corrosion product formed inside lead-bearing pipes or lead-containing faucets as a tetravalent solid in the drinking water distribution system when free chlorine is used as the disinfectant. A dramatic increase of lead concentration in drinking water is reported due to a change in disinfectant from free chlorine to chloramine, thus causing lead poisoning for residents especially for children. The nPbO2(s) particles may enter the surface water via direct or indirect pathways. The stability of nPbO2 plays a key role in determining lead pollution in drinking water and receiving water bodies. Lead is a toxic metal and possible human carcinogen that can cause a variety of adverse health effects including neurotoxicity, nephrotoxicity, genotoxicity etc. However, the toxicity of nPbO2, its environmental fate associated with water matrices and impact to human health and wildlife safety remain unknown. The goal of this project is to establish a systematic in vitro/in vivo detection system that can effectively assess casual toxicity of nPbO2 and its associated species. We propose a two-stage study that comprises of high throughput in vitro cell culture system with the human and in vivo biomarker assays using medaka fish (Oryzias latipes) as an alternative animal model to examine the toxic effects of three lead species including nPbO2 (<100 nm), bulky PbO2 (bPbO2, 200 nm) and Pb2+ ion (the positive control). Stage I (including task 1-3) studies focus on development of a bio-analytical approach to understand the causal toxicity of three lead species at environmentally relevant levels. Stage II (including task 4-6) studies aim to understand all fundamental research questions regarding to bioasscessibility/bioaccumulation (the first year aim), nanotoxicity mechanisms (the second year aim) and bioavailability/ecological risk (the third year aim) of nPbO2 and related lead species, based on results obtained from in vitro and in vivo studies. The research scheme for a three-year span is illustrated in Figure 1. Overall, we envision that results from this project will provide scientific and regulatory communities with integrated information about nPbO2 regarding to (1) modes of toxic action; (2) the fate and toxic impact on human health and ecosystems; (3) the use of fish as an alternative model for nanotoxicology. These results identify an appropriate strategy and critical endpoints for evaluating toxic impact or ecological risk of nPbO2 particles on human health and aquatic life. The outcome can not only accelerate the replacement of lead pipes or lead-containing materials from the drinking water system, but also establish a regulatory guideline of preventing lead contamination in drinking water and aquatic ecosystems.
Keyword(s)
奈米二氧化鉛(nPbO2)
奈米顆粒
自來水
奈米毒性評估
生物指標試驗。
Nanoparticles (NPs)
Nanoscale Lead Dioxide (nPbO2)
Nanotoxicology
Drinking Water
Biomarker Assays.
