以不同營養階層之毒性試驗評估常見有機防曬劑之毒性研究

Abstract

有機紫外線防曬劑(Organic UV-filters)屬於個人保健用品，主要用途為吸收紫外線以便於保護人體皮膚避免產生傷害或癌症。除此之外，它還被大量運用在日常生活產品中如：臉面乳、洗髮乳、護唇膏及包裝材料等。有機紫外線防曬劑在這些產品中的添加比例可高達10%，其使用量及在環境中被測出之濃度也逐年提升。為了瞭解有機紫外線防曬劑對不同營養階層間之敏感度表現以及評估有機紫外線防曬劑是否對水體環境產生衝擊，本研究於有機紫外線防曬劑中挑選4種常用之化合物分別是Benzophenone-3(BP-3)、Benzophenone-4(BP-4)、2-Ethylhexyl 4-methoxycinnamate(EHMC)及Octocrylene(OC)，來進行不同營養階層之水生生物(月牙藻、水蚤及鯉魚)之毒性評估。 物種敏感度結果顯示，在不同營養階層間，月牙藻對BP-3及EHMC最為敏感，其半影響濃度(EC50)分別為0.572及0.102 mg/L，未被觀察之影響濃度(No Observed Effect Concentration, NOEC)值分別為0.041及0.036 mg/L；水蚤對OC最為敏感，其EC50值為0.110 mg/L， NOEC值為0.004 mg/L；鯉魚對4種有機紫外線防曬劑敏感度皆小於上述兩種水生生物。 在毒性評估方面，本研究利用急性毒性及慢性毒性試驗結果中之最敏感物種之EC50及NOEC數據，以及環境中量測之有機紫外線防曬劑最高濃度(maximum Measured Environment Concentration, MECmax)，分別求出急毒之風險商數以及慢毒之風險商數。結果顯示BP-3及BP-4無論經由急毒或慢毒性之毒性評估，所求得之風險商數(RQ)值皆小於1，顯示此兩物種在環境中並無危害性。然而OC之分析結果卻顯示，其以急毒或慢毒性所求得之風險商數(RQ)值皆大於1，顯示OC在環境中具有顯著之危害性。EHMC於急毒之風險商數值大於1，卻在慢毒之風險商數值小於1。由於存在於水體中之有機紫外線防曬劑相當微量且停留時間相當長，因此對於EHMC而言，相較於急毒性，慢毒性之風險商數較適合用於毒性評估，儘管EHMC被評估為對環境無危害性，不過也應加強對EHMC之使用量之監控。

Organic ultraviolet (UV) filters are kind of personal care products, and it is mainly used to absorb UV radiation for protecting human’s skin from UV-induced damage or skin cancer. In addition, organic UV-filters are largely used in daily necessities including facial cleanser, shampoo, lip balm and packing materials, etc. The content of organic UV-filters in these products can be up to 10 %, and both of its usage amount and the concentration measured in the environment also increase in these years. In order to realize the sensitivity of organic UV filters on different trophic levels and to evaluate the impact of organic UV filters on aqueous environment, we chose four compounds for experiment which are Benzophenone-3(BP-3), Benzophenone-4(BP-4), Ethylhexyl methoxycinnamate(EHMC), Octocrylene(OC) commonly used in organic UV filters to conduct the toxicity assessment for the aquatic organisms (pseudokirchneriella subcapitata, daphnia magna, and cyprinus carpio) in different trophic levels. The results from species sensitivity test show that among different trophic levels, the pseudokirchneriella subcapitata has the highest sensitivity to the BP-3 and EHMC, in which the 50 % effective concentrations (EC50) are 0.572 and 0.102 mg/L, respectively, and the no observed effect concentration (NOEC) values are 0.041 and 0.036 mg/ L, respectively. For daphnia magna, it is most sensitive to the OC with an EC50 of 0.110 mg/L and a NOEC of 0.004 mg/L. The sensitivity of these four organic UV filters compounds on cyprinus carpio were found to be lower than those of the above two aquatic organisms. For the toxicity assessment, the data from the most sensitive species in acute (EC50) and chronic toxicity (NOEC) tests together with the maximum measured environment concentration (MECmax) of the organic UV-filters are used to calculate the risk quotient (RQ) for acute and chronic toxicity, respectively. Results show that for the BP-3 and BP-4, the RQ value for both acute and chronic toxicity are calculated to be less than 1, indicating that these two species have insignificant effect to the environment. However, the RQ value of the OC was found to be larger than 1, which means that it has a significant effect to the environment. For the EHMC, the RQ value of acute toxicity is larger than 1 while that of chronic toxicity is less than 1. The mount of organic UV-filters in aqueous are very little and its residence time are very long; therefore, for the EHMC, the RQ value of acute toxicity is more reliable for toxicity assessment as compared to that of chronic toxicity. Although EHMC have insignificant effect to the environment , the amount of usage should be monitored.