市售噴劑產生之氣懸銀/二氧化鈦奈米顆粒之人體暴露風險評估

Abstract

奈米銀與奈米二氧化鈦因其具高效之抗菌力及紫外線吸收力，被廣泛應用於消毒劑與防曬噴霧中。然於奈米噴霧產品使用過程中所釋放出之奈米顆粒，經由呼吸進入至人體中可能引起肺臟不適反應。多篇研究已證實奈米銀與奈米二氧化鈦經吸入所造成之毒性，使用奈米銀與奈米二氧化鈦噴劑之過程可能存在相關健康風險。因此本研究期望整合暴露分析與鼠類動物實驗結果，評估人類吸入奈米銀與奈米二氧化鈦所造成之潛在健康風險。暴露分析乃利用以生理為基礎之肺泡沉積模式與以生理為基礎之肺臟模式，評估因長期暴露所造成肺臟奈米銀與奈米二氧化鈦累積劑量。肺臟中奈米顆粒累積劑量與肺臟發炎反應之劑量反應關係可由希爾模式進行描述，韋伯閾值模式用以推估特定嗜中性球上升幅度之累積劑量閾值，最後以機率風險模式及風險商數評估潛在健康風險。風險評估結果顯示，於密集使用情境下，長期使用含小粒徑奈米銀 (中數粒徑約為30 nm) 之奈米銀噴劑將有約50% 之機率其風險商數大於1。長期使用乳液黏性低，單次按壓釋放量大之奈米二氧化鈦防曬噴霧將造成最高相對風險。此外，基於最保守累積劑量閾值與使用情境，本研究推估奈米噴霧產品每日使用建議上限，作為消費者之使用建議。奈米銀之每日閾值暴露時間中位數為2.29 h day-1 (95% 信賴區間：0.83–6.36 h day-1)，奈米銀噴劑與奈米二氧化鈦防曬噴霧之每日建議使用量分別為58.37 g (23.82–144.05 g) 與 39.29 g (10.85–145.50 g)，每日建議按壓次數中位數分別為38下 (16–97下) 與 66下 (18–245下)。本研究提供具系統性之方法，評估因長期暴露噴霧產品釋出之氣懸奈米銀與奈米二氧化鈦所產生之潛在健康風險，並提出使用建議以避免危害發生。

Silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiO2 NPs) have been widely applied in disinfectant and sunscreen spray for their antimicrobial efficacy and high absorptivity to ultraviolet. However, lung adverse response may be induced by inhalation of airborne NPs while using spray products. Studies have proved the toxic effects of inhaled AgNPs and TiO2 NPs. Related health risk was considered to exist in the application of sprays containing AgNPs or TiO2 NPs. Therefore, we aimed to estimate potential human health risk of inhaled AgNPs and TiO2 NPs by integrating the exposure analysis and murine-related effect data. The compartmentalized physiologically based alveolar deposition model and the physiologically based lung models were employed to predict the lung AgNPs and TiO2 NPs burden for long-term exposure. A Hill-based dose-response model was used to describe the relationship between lung inflammation and NPs accumulation. The Weibull threshold model was used to estimate the threshold accumulated amounts causing specific levels of maximum neutrophils elevation effect. Moreover, the probabilistic risk model and hazard quotients were used to estimate the potential health risk. Results of risk assessment indicate that the risk probability was about 50% that the hazard quotient estimates of AgNPs-containing deodorant with a count median diameter ≈30 nm exceeded 1. Application of TiO2 NPs-containing spray with lotion of lowest viscosity and larger emitted volumn per action would pose highest relative risk. Based on the most conservative threshold accumulated amounts and application scenarios, we estimated the suggested upper limits of daily exposure duration for AgNPs-containing sprays (median: 2.29 h day-1, 95% confidence interval: 0.83–6.36 h day-1), daily using amounts (58.37 g, 23.82–144.05 g; 39.29 g, 10.85–145.50 g) and pressing number (38, 16–97; 66, 18–245) for both AgNPs and TiO2 NPs-containing sprays, respectively, as recommendation for consumers in using nanomaterial-containing spray products. This study provided a mechanistic approach for estimating potential health risk for long-term exposure to airborne AgNPs and TiO2 NPs from spray products and recommendation for daily application.