Vulpes vulpes_tissue composition_Total mercury

This data set concerns the tissue composition (water and lipid proportions) and total mercury in wet, dry and dry-lipid extracted form for red fox tissues (Vulpes vulpes), collected between 2012 and 2020. Contaminant concentrations in wildlife toxicology studies are inconsistently expressed in wet or dry mass units, or even on a lipid-normalized basis, but tissue composition is rarely reported, and the conversion between dry and wet mass units, notably, is often based on assumed empirical moisture contents in tissues. However, diverse factors (e.g., tissue, storage conditions) may affect tissue composition and render comparisons between studies difficult or potentially biased. We used these data as an illustration, to quantify the effects of diverse variables on moisture and lipid contents and their consequences on contaminant concentration in different tissues, when converting between wet and dry mass units (lipid extracted or not). We found that moisture content differed largely between organs, enough to preclude the use of a single conversion factor, and decreased rapidly yearly by 1% when stored in a -80°c freezer. Although most fox tissues have low lipid concentrations, lipid content affected water content and their extraction affected the wet to dry mass conversion factor. We thus recommend reporting tissue composition (at least water and lipid contents) systematically in toxicology studies and using tissue/species specific conversion factors to convert between dry and wet mass concentration.

本数据集涵盖2012至2020年间采集的赤狐（Vulpes vulpes）组织的组成（水分与脂质占比），以及湿重、干重和脱脂干重形式下的总汞含量。野生动物毒理学研究中，污染物浓度的表达形式并不统一，常采用湿重、干重单位，甚至采用脂质归一化基准；但组织组成却鲜有报道，且干湿质量单位间的转换通常基于假设的组织经验含水率。然而，多种因素（如组织类型、储存条件）可影响组织组成，导致不同研究间的对比困难，甚至引入偏倚。我们以本数据集为示例，量化了多种变量对水分与脂质含量的影响，以及在进行干湿质量单位（是否脱脂）转换时，这些因素对不同组织中污染物浓度的影响。研究发现，不同器官间的含水率差异显著，足以说明不能使用单一转换因子；且在-80℃冰箱储存时，含水率每年会快速下降1%。尽管多数赤狐组织的脂质浓度较低，但脂质含量会影响水分含量，而脂质提取操作也会改变湿重与干重的转换系数。因此，我们建议在毒理学研究中系统报告组织组成（至少涵盖水分与脂质含量），并采用针对特定组织/物种的转换因子，以实现干重与湿重浓度间的相互转换。