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

海洋生物中存在数以千计的卤素，特别是含氯的次生代谢物，海洋天然产物化学家早就证明了这一点。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，这使得它们的最终来源受到质疑。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(HOCs)和海洋环境中自然产生的HOCs的一种手段。这项调查试图使用人类来源化合物所隐含的化石燃料衍生碳的预期同位素耗竭来测量几个人为还是自然来源的HOC的化合物特定同位素14C丰度。考虑到HOCs的稳定氯同位素比率，可以进一步区分来源。稳定的同位素氯(D37Cl)比率，目前仅为此目的进行了初步研究，与工业合成中观察到的氯同位素效应相比，在酶控制的生物氯化反应中可能会显示出更大的氯同位素效应，或者只是不同的效应。双同位素方法可能还有助于解开这些分子在自然环境中可能经历的复杂来源、广泛分布和化学转化。拟开展的活动包括研究生培训、利用独特的分析能力和基础设施以及推动就一个具有高度科学兴趣的问题继续开展国际合作。HOCs在海洋环境中的顽抗或反应具有重要的社会意义和政策意义，涉及到HOCs在环境、海洋生物和人类中的环境持久性、生物蓄积性和毒性效应。

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.