Institute of Marine Research, P.O. Box 1870 Nordnes, NO-5817, Bergen, Norway; National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, DK-2800, Kgs. Lyngby, Denmark.
Institute of Marine Research, P.O. Box 1870 Nordnes, NO-5817, Bergen, Norway.
Environ Pollut. 2023 Oct 1;334:122176. doi: 10.1016/j.envpol.2023.122176. Epub 2023 Jul 10.
Microalgae and blue mussels are known to accumulate undesirable substances from the environment, including arsenic (As). Microalgae can biotransform inorganic As (iAs) to organoarsenic species, which can be transferred to blue mussels. Knowledge on As uptake, biotransformation, and trophic transfer is important with regards to feed and food safety since As species have varying toxicities. In the current work, experiments were conducted in two parts: (1) exposure of the microalgae Diacronema lutheri to 5 and 10 μg/L As(V) in seawater for 4 days, and (2) dietary As exposure where blue mussels (Mytilus edulis L.) were fed with D. lutheri exposed to 5 and 10 μg/L As(V), or by aquatic exposure to 5 μg/L As(V) in seawater, for a total of 25 days. The results showed that D. lutheri can take up As from seawater and transform it to methylated As species and arsenosugars (AsSug). However, exposure to 10 μg/L As(V) resulted in accumulation of iAs in D. lutheri and lower production of methylated As species, which may suggest that detoxification mechanisms were overwhelmed. Blue mussels exposed to As via the diet and seawater showed no accumulation of As. Use of linear mixed models revealed that the blue mussels were gradually losing As instead, which may be due to As concentration differences in the mussels' natural environment and the experimental setup. Both D. lutheri and blue mussels contained notable proportions of simple methylated As species and AsSug. Arsenobetaine (AB) was not detected in D. lutheri but present in minor fraction in mussels. The findings suggest that low-trophic marine organisms mainly contain methylated As species and AsSug. The use of low-trophic marine organisms as feed ingredients requires further studies since AsSug are regarded as potentially toxic, which may introduce new risks to feed and food safety.
微藻和贻贝已知会从环境中积累有害物质，包括砷（As）。微藻可以将无机砷（iAs）生物转化为有机砷化合物，这些化合物可以转移到贻贝中。关于饲料和食品安全，了解砷的吸收、生物转化和营养转移非常重要，因为砷的形态具有不同的毒性。在当前的工作中，进行了两部分实验：（1）将微藻 Diacronema lutheri 暴露于海水中的 5 和 10μg/L As(V) 中 4 天；（2）贻贝（Mytilus edulis L.）通过食用暴露于 5 和 10μg/L As(V) 的 D. lutheri，或通过在海水中暴露于 5μg/L As(V)，总共 25 天，来进行饮食中砷的暴露。结果表明，D. lutheri 可以从海水中吸收砷并将其转化为甲基化砷化合物和砷糖（AsSug）。然而，暴露于 10μg/L As(V)会导致 D. lutheri 中积累 iAs，并减少甲基化砷化合物的产生，这可能表明解毒机制已经失效。通过饮食和海水暴露于砷的贻贝没有积累砷。使用线性混合模型表明，贻贝逐渐失去了砷，这可能是由于贻贝自然环境和实验设置中的砷浓度差异所致。D. lutheri 和贻贝都含有大量的简单甲基化砷化合物和 AsSug。D. lutheri 中未检测到砷甜菜碱（AB），但在贻贝中存在少量。研究结果表明，低营养级的海洋生物主要含有甲基化砷化合物和 AsSug。由于 AsSug 被认为具有潜在毒性，可能会给饲料和食品安全带来新的风险，因此需要进一步研究将低营养级海洋生物用作饲料成分的问题。
