Tissue metal concentrations and metal transfer functions of Glaucous Gulls (Larus hyperboreus) from Bjørnøya and Jan Mayen

Heavy metals (Cd, Cu, Fe, Mn and Zn) concentrations were determined in different tissues (muscle, kidney, liver, brain, gonads, heart and feathers) of Glaucous Gulls (Larus hyperboreus) from Bjornoya and Jan Mayen. The age and spatial dependent variations in heavy metals were quantified and interpreted in view of the three chemometric techniques, i.e. non-parametric Mann-Whitney U test, redundancy gradient analysis and detrended correspondence analysis. The Glaucous Gulls from Bjornoya contained significantly higher (p < 0.05) levels of Cd, Cu and Zn than those inhabited Jan Mayen. Adult birds were characterized by greater (p < 0.01) concentration of muscle, hepatic and renal heavy metals in comparison to chicks. Insignificantly higher slope constant Zn/Cd for the liver than for the kidney may reflect insignificant Cd exposure. Estimate of transfer factor (TF) allows us to assess variations in heavy metal concentrations during the individual development of Glaucous Gulls. It may be stated that there is a distinct increase of bioaccumulation of all the studied metals during subsequent stages of the bird life.

本研究测定了采自熊岛（Bjornoya）与扬马延岛（Jan Mayen）的北极鸥（Glaucous Gull，*Larus hyperboreus*）不同组织——肌肉、肾脏、肝脏、大脑、性腺、心脏及羽毛——中的重金属（heavy metals）浓度，被测重金属包括镉（Cd）、铜（Cu）、铁（Fe）、锰（Mn）与锌（Zn）。研究针对重金属浓度的年龄依赖性与空间依赖性差异开展定量分析，并结合三种化学计量学技术（chemometric techniques）——非参数曼-惠特尼U检验（non-parametric Mann-Whitney U test）、冗余梯度分析（redundancy gradient analysis）与除趋势对应分析（detrended correspondence analysis）——进行解读。结果显示，采自熊岛的北极鸥体内Cd、Cu与Zn的浓度显著高于扬马延岛种群（p < 0.05）；成鸟肌肉、肝脏与肾脏组织内的重金属浓度显著高于雏鸟（p < 0.01）。肝脏的锌/镉斜率常数略高于肾脏，但差异无统计学意义，该结果或可反映其镉暴露水平较低。通过估算转移因子（transfer factor, TF），可评估北极鸥个体发育过程中重金属浓度的变化规律。研究表明，在该鸟类后续的生命阶段中，所有被测重金属的生物富集（bioaccumulation）水平均呈现显著升高趋势。