NORCE Norwegian Research Centre, Mekjarvik 12, 4072, Randaberg, Norway.
The Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway.
Aquat Toxicol. 2020 May;222:105453. doi: 10.1016/j.aquatox.2020.105453. Epub 2020 Feb 18.
Anti-parasitic drugs used in the aquaculture industry are discharged to the sea after treatment of salmon. In this study, the effects of azamethiphos (AZA) in the Salmosan® formulation and deltamethrin (DEL) in the Alpha Max® formulation, have been assessed in Northern shrimp larvae (Pandalus borealis) when administered both separately and in combination. The exposure concentrations were 100 ng/L for AZA and 2 ng/L for DEL, each representing a 1000-fold dilution of the prescribed concentrations for salmon. These two chemicals were combined at these concentrations to give a third treatment (AZA + DEL). When larvae were exposed for two hours on the first, second and third days post hatch (dph), significantly increased mortality and reduced swimming activity were observed for larvae from the DEL and combined AZA + DEL treatments 4 dph, though not in larvae from the AZA treatment. A single pulse exposure, delivered on the first day post hatch, caused similar effects on mortality and swimming activity 4 dph as the three-pulse exposure. Mortality was driven by the presence of DEL in both experiments, with no amplification or reduction of effects observed when DEL and AZA were combined. Larvae were observed for 13 days following the single pulse exposure, with food limitation introduced as an additional stressor on day 4. In the DEL and AZA + DEL treatments mortality continued to increase regardless of food level, with no larvae completing development to stage II. The overriding toxicity of DEL masked any potential effects the reduced food ration may have exerted. Swimming activity was lower for AZA treated larvae than Control larvae 13 dph, when both groups were fed daily, though no other significant changes to mortality, development to stage II, feeding rate or gene expression were observed. Food limited Control and AZA larvae had lower swimming activity and feeding rate than daily fed Control larvae, with expression of pyruvate kinase and myosin genes also downregulated. However, there was no negative effect on survival or successful development to stage II in these treatments. In addition, mesencephalic astrocyte-derived neurotropic factor was downregulated in food limited Control larvae when compared with the daily fed Controls. Results from this study together with reported estimates of dispersion plume concentrations of discharged pesticides indicate that toxic concentrations of deltamethrin could reach shrimp larvae several kilometers from a treated salmon farm.
水产养殖中使用的驱虫药物在处理鲑鱼后被排放到海水中。在这项研究中，我们评估了 Salmosan®制剂中的甲拌磷 (AZA) 和 Alpha Max®制剂中的溴氰菊酯 (DEL) 分别单独和联合使用时对北方虾幼虫 (Pandalus borealis) 的影响。暴露浓度分别为 AZA 为 100ng/L，DEL 为 2ng/L，均为鲑鱼规定浓度的 1000 倍稀释。这两种化学物质以这些浓度组合成第三种处理（AZA+DEL）。当幼虫在孵化后第 1、2 和 3 天（dph）暴露两小时时，暴露于 DEL 和联合的 AZA+DEL 处理组的幼虫在第 4 dph 时表现出明显增加的死亡率和减少的游泳活动，而暴露于 AZA 处理组的幼虫则没有。单次脉冲暴露，在孵化后第 1 天进行，在第 4 dph 时对死亡率和游泳活动产生了类似的影响，与三次脉冲暴露相同。在两项实验中，死亡率都是由 DEL 引起的，当 DEL 和 AZA 联合使用时，没有观察到放大或减少效果。在单次脉冲暴露后，幼虫被观察了 13 天，并在第 4 天引入食物限制作为额外的应激源。在 DEL 和 AZA+DEL 处理组中，死亡率继续增加，无论食物水平如何，没有幼虫完成到第 II 阶段的发育。DEL 的压倒性毒性掩盖了减少的食物量可能产生的任何潜在影响。在第 13 天，与对照组幼虫相比，接受 AZA 处理的幼虫的游泳活动较低，尽管没有观察到死亡率、发育到第 II 阶段、摄食率或基因表达的其他显著变化。与每日喂食的对照组幼虫相比，食物受限的对照组和 AZA 幼虫的游泳活动和摄食率较低，丙酮酸激酶和肌球蛋白基因的表达也下调。然而，在这些处理中，对存活或成功发育到第 II 阶段没有负面影响。此外，与每日喂养的对照组相比，食物受限的对照组幼虾脑中星形胶质细胞衍生的神经营养因子下调。本研究结果以及报道的排放农药扩散羽浓度估计表明，有毒浓度的溴氰菊酯可能会到达距处理鲑鱼养殖场几公里的虾幼虫。
