Isotopic Constraints on the Origin of Bioaccumulating Halogenated Organic Compounds in the Ocean

摘要：海洋天然产物化学家长期以来一直记录了海洋生物中存在的数千种含卤素，尤其是含氯的次级代谢产物。然而，海洋生物群中存在的许多卤代有机化合物在结构上与特定的人造化学品非常接近，使其最终来源成为问题。提出了一种多同位素丰度测量方法，作为区分人为卤代有机化合物和海洋环境中自然产生的卤代有机化合物的一种手段。这项调查旨在测量化合物特定的同位素14 C丰度的几个HOCs的人为与自然起源是不确定的，使用预期的同位素耗尽的任何化石燃料衍生的碳暗示的生物来源的化合物。通过考虑HOCs的稳定氯同位素比值，可以进一步进行来源判别。稳定的同位素氯（d 37Cl）的比例，还只是初步研究了这一目的，可能会表现出更大的，或只是不同的，在酶控制的生物氯化过程中的氯同位素效应相比，在工业合成过程中观察到的。一个双同位素的方法可能是另外有用的，在解开这两个复杂的来源，广泛的分布和化学转化，这些分子可能会在自然环境中经历。拟开展的活动包括培训研究生，利用独特的分析能力和基础设施，并就具有高度科学意义的问题继续开展国际合作。HOCs在海洋环境中的不稳定性或反应性对于HOCs在环境、海洋生物和人类中的环境持久性、生物累积性和毒性影响等社会关注和政策具有重要意义。

ABSTRACTOCE-01221181The presence of thousands of halogen and especially chlorine containing secondary metabolites in marine organisms has long been documented by marine natural products chemists. However, the presence in marine biota of many halogenated organic compounds very close in structure to specific man-made chemicals leaves their ultimate source in question. A multi-isotopic abundance measurement approach is suggested as a means of differentiating anthropogenic halogenated organic compounds (HOCs) from those arising naturally in the marine environment. This investigation seeks to measure the compound specific isotopic 14C abundance of several HOCs whose anthropogenic vs natural origin is uncertain, using the expected isotopic depletion of any fossil fuel derived carbon implied for anthropogenically sourced compounds. Further source discrimination may be afforded by consideration of the stable chlorine isotopic ratios of HOCs. Stable isotopic chlorine (d 37Cl) ratios, as yet only preliminarily studied for this purpose, may be expected to exhibit larger, or simply different, chlorine isotope effects during enzymically controlled biochlorinations compared to those observed during industrial synthesis. A dual isotope approach may be additionally useful in unraveling both the complex sources, widespread distribution and chemical transformations that these molecules may undergo in the natural environment. Proposed activities to be undertaken include graduate student training, employing unique analytical capabilities and infrastructure and enabling continuance of international collaborations on a problem of high scientific interest. The recalcitrance or reactivity of HOCs in the marine environment has important implications for societal concern and policy as to the environmental persistence, bioaccumulative properties and toxic effects of HOCs in the environment, in marine life, and in humans.