Odontocetes are considered ideal sentinel species to monitor environmental trace element concentrations. Although frozen tissues are preferable for trace element analysis, formalin-fixed tissues are often the only samples available; however, it is uncertain whether formalin fixation alters tissue trace element concentrations. To explore whether formalin-fixed tissues could be utilized for toxicology studies, concentrations of 14 trace elements (arsenic [As], cadmium, cobalt, chromium, copper, iron, mercury, manganese, nickel, lead, selenium, tin, vanadium, and zinc [Zn]) were measured in frozen and formalin-fixed bottlenose dolphin (Tursiops truncatus) tissues following short-term (6 wk; tissues: blubber, liver, and lung) and long-term preservation (3-7 yr; tissues: blubber, brain, kidney, liver, lung, and skin) using inductively coupled plasma mass spectrometry. Following both short-term and long-term preservation, there were significant differences in tissue trace element concentrations between preservation methods. Some trace elements were found in greater concentrations in frozen tissues compared with formalin-fixed tissues, suggesting leaching (e.g., mean As concentrations were between 1.4 and 7.6 times greater in frozen tissues). In contrast, other trace elements were found in greater concentrations in formalin-fixed tissues compared with frozen tissues, suggesting contamination (e.g., mean Zn concentrations were up to 8.7 times higher in some formalin-fixed tissues). Our results suggest that it may be possible to account for the effects of formalin fixation for some trace elements, but leaching and contamination should be carefully considered. Environ Toxicol Chem 2020;39:1149-1164. © 2020 SETAC.

中文翻译：

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福尔马林固定对宽吻海豚（Tursiops truncatus）组织中微量元素浓度的影响。

牙本质动物被认为是监测环境微量元素浓度的理想定点物种。尽管冷冻组织更适合进行微量元素分析，但福尔马林固定的组织通常是唯一可用的样品。但是，福尔马林固定是否会改变组织中微量元素的浓度尚不确定。为了探究是否可以将福尔马林固定的组织用于毒理学研究，使用14种微量元素（砷[As]，镉，钴，铬，铜，铁，汞，锰，镍，铅，硒，锡，钒和在短期（6周；组织：脂，肝和肺）和长期保存（3-7年；组织：组织：冷冻和福尔马林固定的宽吻海豚（Tursiops truncatus）组织中测量锌（Zn））脂，脑，肾，肝，肺，和皮肤）使用电感耦合等离子体质谱法。在短期和长期保存之后，保存方法之间的组织微量元素浓度存在显着差异。与福尔马林固定的组织相比，在冷冻的组织中发现了一些微量元素，浓度更高，这表明存在浸出现象（例如，在冷冻的组织中，平均As浓度高出1.4至7.6倍）。相反，与冷冻组织相比，在福尔马林固定的组织中发现了其他痕量元素，其浓度更高，这表明存在污染（例如，在某些福尔马林固定的组织中，平均锌浓度高出8.7倍）。我们的结果表明，可能有可能考虑到福尔马林固定对某些微量元素的影响，但应仔细考虑浸出和污染。Environ Toxicol Chem 2020; 39：1149-1164。©2020 SETAC。