Wildlife Conservation Society Canada, Sudbury, ON, Canada; Laurentian University, Vale Living with Lakes Centre, Sudbury, ON, Canada.
Laurentian University, Vale Living with Lakes Centre, Sudbury, ON, Canada; Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry, Sudbury, ON, Canada.
Chemosphere. 2022 Dec;308(Pt 1):136140. doi: 10.1016/j.chemosphere.2022.136140. Epub 2022 Aug 27.
Elevated concentrations of total arsenic (As) have been reported in boreal freshwater fish in both human-impacted and relatively pristine areas. We assessed the arsenic speciation profiles in muscle tissue of six fish species (n = 300) sampled from nine locations across a remote freshwater watershed in northern Ontario, Canada, extending from inland headwater lakes to the coastal marine confluence. Of the five arsenic species measured, only arsenobetaine (AsB) and dimethylarsinic acid (DMA) were detected in these fish. Riverine fish had up to 10-fold higher total [As] when compared to lacustrine fish. On average, these riverine fish also had higher percentages of AsB (%AsB, 60 ± 26%) and lower percentages of unmeasured arsenic (%UNM, 20 ± 21%), compared to lacustrine fish (28 ± 18% and 52 ± 21% %AsB and %UNM, respectively). DMA percentages (%DMA) were relatively consistent across the watershed, averaging 20 ± 21% across all fish. We examined ecological drivers of As speciation and found that %AsB increased slightly with fish weight in large-body predatory fish, but not in forage fish or insectivores. Furthermore, %AsB was positively related to trophic elevation (inferred from δN) in lacustrine fish across 3 out of 4 communities and within some populations. Lastly, riverine fish with a more marine-based diet had markedly higher %AsB when compared to fish with more freshwater-based diets, indicating an effect of anadromy on arsenic speciation. Overall, knowledge on arsenic speciation in freshwater fish has been limited and these results indicate potential drivers that can be considered in future studies. Furthermore, the absence of toxic inorganic As species in these boreal fish is an important consideration for future environmental monitoring practices and risk assessments, some of which assume 10-20% of total [As] in fish is present as toxic inorganic As. Additional studies on As bioaccumulation and biotransformation are needed in freshwater systems, particularly at the base of aquatic food webs.
在受到人类影响和相对原始的地区的北方冷水域淡水鱼中，总砷 (As) 的浓度都有所升高。我们评估了在加拿大安大略省北部偏远的淡水流域的九个地点采集的六种鱼类（n = 300）的肌肉组织中的砷形态分布，该流域从内陆源头湖延伸到沿海海洋汇合处。在所测量的五种砷物种中，只有砷甜菜碱 (AsB) 和二甲基砷酸 (DMA) 在这些鱼中被发现。与湖泊鱼类相比，河流鱼类的总 [As] 高了 10 倍。平均而言，与湖泊鱼类相比，这些河流鱼类的 AsB 百分比（%AsB，60 ± 26%）更高，未测量的砷百分比（%UNM，20 ± 21%）更低。（分别为 28 ± 18%和 52 ± 21%的%AsB 和%UNM）。DMA 百分比（%DMA）在整个流域相对一致，所有鱼类的平均值为 20 ± 21%。我们研究了砷形态的生态驱动因素，发现大体型掠食性鱼类的 AsB 百分比随着鱼体重量略有增加，但在饲料鱼或食虫鱼类中则不然。此外，在 4 个社区中的 3 个社区以及一些种群中，湖泊鱼类的 %AsB 与营养级（根据 δN 推断）呈正相关。最后，与具有更淡水饮食的鱼类相比，具有更多海洋饮食的洄游鱼类的 %AsB 明显更高，这表明溯河产卵对砷形态的影响。总的来说，对淡水鱼中砷形态的认识一直有限，这些结果表明可以在未来的研究中考虑一些潜在的驱动因素。此外，这些北方冷水域鱼类中没有有毒的无机 As 物种，这对于未来的环境监测实践和风险评估非常重要，因为其中一些假设鱼类中总 [As] 的 10-20% 是以有毒的无机 As 形式存在的。在淡水系统中，特别是在水生食物网的底部，需要进一步研究砷的生物积累和生物转化。
