Department of Environmental Science, Stockholm University, Stockholm, Sweden.
Department of Environmental Science, Stockholm University, Stockholm, Sweden and Environmental Research Institute (ERI), School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China.
Environ Sci Process Impacts. 2021 May 26;23(5):689-698. doi: 10.1039/d1em00009h.
Cedarwood oil is an essential oil used as a fragrance material and insect repellent. Its main constituents are sesquiterpenes which are potentially bioaccumulative according to the REACH screening criteria. Cedarwood oil is a complex mixture of hydrophobic and volatile organic chemicals. The volatility and limited water solubility of its constituents are a challenge for standard bioconcentration factor (BCF) test methods using aqueous exposure. We used an abbreviated dietary exposure in vivo testing protocol with internal benchmark substances as "internal standards" to derive the BCF of cedarwood oil constituents using rainbow trout (Oncorhynchus mykiss). Internal benchmarking proved to be a useful tool to control for inter-individual variability, enabling us to calculate the BCF for all major cedarwood oil constituents as a mixture. We found that the BCF of two out of six analysed cedarwood oil constituents exceed a BCF of 5000 and two others exceed a BCF of 2000 (90% confidence level) even though we found evidence for biotransformation for individual constituents. The results of this study indicate that more work is warranted to study the bioaccumulation of essential oils and highlights the utility of internal benchmarking in in vivo dietary exposure BCF tests to increase robustness and allow for the BCF measurement of complex mixtures.
雪松木油是一种用作香料和驱虫剂的精油。根据 REACH 筛选标准，其主要成分是具有潜在生物蓄积性的倍半萜烯。雪松木油是一种复杂的疏水性和挥发性有机化学品混合物。其成分的挥发性和有限的水溶性给使用水暴露的标准生物浓缩系数（BCF）测试方法带来了挑战。我们使用了一种简化的体内饮食暴露试验方案，并使用内部基准物质作为“内标”，使用虹鳟鱼（Oncorhynchus mykiss）来推导雪松木油成分的 BCF。内部基准证明是控制个体间变异性的有用工具，使我们能够计算出所有主要雪松木油成分作为混合物的 BCF。我们发现，在分析的六种雪松木油成分中，有两种的 BCF 超过 5000，另外两种的 BCF 超过 2000（90%置信水平），尽管我们发现个别成分存在生物转化的证据。这项研究的结果表明，有必要进一步研究精油的生物蓄积性，并强调了内部基准在体内饮食暴露 BCF 测试中的实用性，以提高稳健性并允许对复杂混合物进行 BCF 测量。
