Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Bruce 2601, ACT, Australia.
Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Bruce 2601, ACT, Australia.
Aquat Toxicol. 2015 Mar;160:22-30. doi: 10.1016/j.aquatox.2014.12.019. Epub 2014 Dec 27.
Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93μg/g dry mass) and cadmium-enriched phytoplankton (1.6-3μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9±0.4μg/g and 23±2μg/g respectively compared to controls 0.97±0.05μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9±0.1μg/g compared to controls 1.2±0.1μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4-21μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.
金属通过水、悬浮沉积物或食物的摄入被滤食性生物积累。吸收途径会影响金属的毒性。将太平洋牡蛎暴露于镉污染的悬浮沉积物（19 和 93μg/g 干重）和富镉浮游植物（1.6-3μg/g 干重）中，测量镉的吸收和影响。牡蛎从低镉和高镉污染的悬浮沉积物处理中积累了相当数量的镉（分别为 5.9±0.4μg/g 和 23±2μg/g，而对照组为 0.97±0.05μg/g 干重）。通过摄入富镉浮游植物，只有少量的镉被吸收（1.9±0.1μg/g，而对照组为 1.2±0.1μg/g）。在镉污染的悬浮沉积物实验中，大部分镉从沉积物中解吸出来，并且太平洋牡蛎中的镉浓度与上覆水中溶解态镉浓度（4-21μg/L）显著相关。在浮游植物喂养实验中，上覆水中的镉浓度<0.01μg/L。在这两个暴露实验中，暴露于镉的牡蛎总抗氧化能力显著降低，脂质过氧化和不稳定溶酶体的百分比显著增加。悬浮沉积物实验中不稳定的溶酶体也来自于暴露于悬浮沉积物的应激。该研究表明，通过悬浮沉积物暴露于镉以及通过摄入浮游植物暴露于低浓度的镉，都会对太平洋牡蛎造成亚致死应激。
