Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, 0349 Oslo, Norway.
Environ Pollut. 2012 May;164:235-41. doi: 10.1016/j.envpol.2012.01.041. Epub 2012 Feb 28.
Transfer of aqueous methylmercury (MeHg) to primary consumers in aquatic foodwebs is poorly understood despite its importance for bioaccumulation of MeHg. We studied bioaccumulation of MeHg in simple aquatic food chains of two humic boreal streams in relation to streamwater chemistry, food web characteristics and dietary fatty acid (FA) biomarkers. Transfer of aqueous MeHg into primary consumers was similar in both streams, resulting in higher MeHg in consumers in the MeHg-rich stream. Trophic enrichment of MeHg and dietary retention of FA biomarkers was the same in both streams, suggesting that exposure to aqueous MeHg at the base of the food chain determined levels of MeHg in biota. In addition, contents of dietary biomarkers suggested that ingestion of algae reduced MeHg bioaccumulation, while ingestion of bacteria stimulated MeHg uptake. Dietary uptake of bacteria could thus be an important pathway for MeHg-transfer at the bottom of food chains in humic streams.
尽管水合甲基汞（MeHg）向水生食物网中的初级消费者转移对其生物积累非常重要，但人们对此知之甚少。我们研究了两种富腐殖质的北方溪流简单水生食物链中 MeHg 的生物积累与溪流水质、食物网特征和膳食脂肪酸（FA）生物标志物之间的关系。两种溪流中，水合 MeHg 向初级消费者的转移情况相似，导致富 MeHg 溪流中的消费者体内 MeHg 含量更高。MeHg 的营养富集和 FA 生物标志物在膳食中的保留在两种溪流中相同，这表明食物链底部暴露于水合 MeHg 决定了生物体内 MeHg 的水平。此外，膳食生物标志物的含量表明，藻类的摄入减少了 MeHg 的生物积累，而细菌的摄入刺激了 MeHg 的吸收。因此，细菌的膳食摄入可能是腐殖质溪流食物链底部 MeHg 转移的一个重要途径。
