Concentrations of persistant organic pollutants in Great skua eggs (Stercorarius skua) from Shetland 1980 and 2008

Concentrations of POPs in Great skua eggs from Shetland are among the highest in North Atlantic seabirds, with up to 11,600 µg/kg (ww) DDE and up to 17,900 µg/kg ww SumPCB. Concentrations of legacy POPs were significantly lower in 2008 than 1980. Decreases were greatest for least persistent compounds. Median SumPBDEs increased from 99 µg/kg ww in 1980 to 173 µg/kg ww in 2008. There were changes in Great skua breeding season diet, with more adult Herring and Mackerel and less Sandeel. These changes increase exposure to POPs, since Herring and Mackerel accumulate more POPs than Sandeels. In both years, eggs with higher d15N had higher POP concentrations. In 1980, birds feeding more on demersal discard fish from trawl fisheries and less on Sandeels, had higher POP levels in eggs. In 2008, individuals feeding more on Herring and Mackerel, and less on discards, had higher POP levels in eggs.

来自设得兰群岛的大贼鸥（Great skua）卵内持久性有机污染物（Persistent Organic Pollutants，简称POPs）浓度位列北大西洋（North Atlantic）海鸟前列，其中二氯二苯基二氯乙烯（DDE）最高可达11600 μg/kg（湿重，wet weight，ww），总多氯联苯（SumPCB）最高可达17900 μg/kg ww。2008年的传统持久性有机污染物（legacy POPs）浓度显著低于1980年，其中低持久性化合物的降幅最为显著。总多溴联苯醚（SumPBDEs）的中位浓度从1980年的99 μg/kg ww升至2008年的173 μg/kg ww。大贼鸥繁殖季的饮食结构发生变化：成体鲱鱼（Herring）与鲭鱼（Mackerel）的摄食占比提升，沙鳗（Sandeel）的摄食占比降低。此类饮食结构变化会增加持久性有机污染物的暴露风险，因鲱鱼与鲭鱼的持久性有机污染物蓄积量高于沙鳗。两个调查年份中，卵内δ15N（氮-15同位素比值）值越高的个体，其卵内持久性有机污染物浓度也越高。1980年时，更多依赖拖网渔业产生的底栖弃渔获物为食、较少捕食沙鳗的大贼鸥，卵内持久性有机污染物浓度更高；2008年时，更多捕食鲱鱼与鲭鱼、较少食用渔业弃渔获物的个体，卵内持久性有机污染物浓度更高。