Edible cod liver products including cod liver oil and canned cod liver, sampled over the last five decades from the North Atlantic region, including the Baltic Sea were analysed for a set of persistent and toxicologically significant polychlorinated naphthalene (PCN) congeners with some of the highest relative potencies (dioxin-like toxicity) among PCNs. The targeted congeners showed a near-universality of occurrence in all samples apart from the most recent sample of cod liver oil which was assumed to be highly purified, as cod livers from the same period and location showed appreciable amounts of PCNs. The majority of dominant congeners in legacy technical PCN mixtures were absent or occurred in low concentrations, raising the possibility that congeners arising from combustion related sources may be acquiring a greater significance following the decline and elimination of PCN production. The apparent appreciation in the relative amounts of PCN#70 in the last three to four decades may provide support for this view. The PCN contribution to dioxin-like toxic equivalence (TEQ) that was estimated for these samples (range 1.2–15.9 pg TEQ g⁻¹) was significant in comparison to the EU regulated value of 1.75 pg TEQ g⁻¹ for dioxins in fish oils. Most of the TEQ was associated with PCNs 66/67, 64/68, 69 and 73. Although metabolic processes are likely to influence this distribution, the profile is a little different to that observed in the tissues of higher order animals where PCNs #66/67 and #73 may contribute approximately 90% to the summed TEQ.

在过去的五十年中，从包括波罗的海在内的北大西洋地区取样的可食用鳕鱼肝产品，包括鳕鱼肝油和罐装鳕鱼肝，被分析了一套持久的，具有毒理学意义的多氯萘（PCN）同类品，其中一些含量最高PCN之间的相对效力（二恶英样毒性）。靶向同源物在所有样品中均表现出接近普遍性，除了最新的鳕鱼肝油样品被认为是高度纯化的，因为来自同一时期和位置的鳕鱼肝显示出相当数量的PCN。遗留的工业PCN混合物中大多数主要同类物都不存在或浓度很低，随着PCN产量的减少和消除，由燃烧相关源产生的同类物可能具有更大的意义。在过去三到四十年中，PCN＃70相对含量的明显升值可以为这种观点提供支持。这些样品估计的PCN对类二恶英毒性当量（TEQ）的贡献（范围为1.2–15.9 pg TEQ g^-1）与鱼油中二恶英的欧盟规定值为1.75 pg TEQ g ^-1相比具有显着意义。大部分TEQ与PCN 66 / 67、64 / 68、69和73相关。尽管代谢过程可能会影响这种分布，但其特征与在PCN＃66的高阶动物组织中观察到的略有不同。 / 67和＃73可能占总TEQ的大约90％。