Data from: How common road salts and organic additives alter freshwater food webs: in search of safer alternatives

The application of deicing road salts began in the 1940s and has increased drastically in regions where snow and ice removal is critical for transportation safety. The most commonly applied road salt is sodium chloride (NaCl). However, the increased costs of NaCl, its negative effects on human health, and the degradation of roadside habitats has driven transportation agencies to seek alternative road salts and organic additives to reduce the application rate of NaCl or increase its effectiveness. Few studies have examined the effects of NaCl in aquatic ecosystems, but none have explored the potential impacts of road salt alternatives or additives on aquatic food webs. We assessed the effects of three road salts (NaCl, MgCl2 and ClearLane™) and two road salts mixed with organic additives (GeoMelt™ and Magic Salt™) on food webs in experimental aquatic communities, with environmentally relevant concentrations, standardized by chloride concentration. We found that NaCl had few effects on aquatic communities. However, the microbial breakdown of organic additives initially reduced dissolved oxygen. Additionally, microbial activity likely transformed unusable phosphorus from the organic additives to usable phosphorus for algae, which increased algal growth. The increase in algal growth led to an increase in zooplankton abundance. Finally, MgCl2 – a common alternative to NaCl – reduced compositional differences of zooplankton, and at low concentrations increased the abundance of amphipods. Synthesis and applications. Our results indicate that alternative road salts (to NaCl), and road salt additives can alter the abundance and composition of organisms in freshwater food webs at multiple trophic levels, even at low concentrations. Consequently, road salt alternatives and additives might alter ecosystem function and ecosystem services. Therefore, transportation agencies should use caution in applying road salt alternatives and additives. A comprehensive investigation of road salt alternatives and road salt additives should be conducted before wide-scale use is implemented. Further research is also needed to determine the impacts of salt additives and alternatives on higher trophic levels, such as amphibians and fish.道路融雪盐的应用始于20世纪40年代，在除冰雪对交通安全至关重要的地区，其使用量已大幅攀升。目前最常用的道路融雪盐为氯化钠（sodium chloride, NaCl）。然而，氯化钠成本攀升、对人体健康存在负面影响，同时会破坏路边生境，这促使交通管理部门寻求替代融雪盐与有机添加剂，以降低氯化钠的施用量或提升其使用效能。目前鲜有研究探讨氯化钠对水生生态系统的影响，更无相关研究探索道路融雪盐替代品或添加剂对水生食物网的潜在影响。 本研究以氯化物浓度为统一标准，设置具有环境代表性的受试浓度，针对3种道路融雪盐（氯化钠NaCl、氯化镁MgCl₂与ClearLane™）以及2种混有有机添加剂的融雪盐（GeoMelt™与Magic Salt™），评估其对实验水生群落食物网的影响。 研究结果显示，氯化钠对水生群落的影响微乎其微。但有机添加剂的微生物降解过程会在初期降低溶解氧含量。此外，微生物活动可能将有机添加剂中不可利用的磷转化为藻类可利用的磷，从而促进藻类生长；藻类数量的提升又导致浮游动物丰度增加。最后，作为氯化钠常见替代品的氯化镁，可降低浮游动物的群落组成差异，且在低浓度下会增加端足类动物的丰度。 综合与应用。本研究结果表明，替代氯化钠的道路融雪盐以及融雪盐添加剂，即便在低浓度下，也可改变淡水食物网中多个营养级的生物丰度与群落组成。因此，道路融雪盐替代品与添加剂可能会改变生态系统功能与生态系统服务。故此，交通管理部门在使用道路融雪盐替代品及添加剂时应保持谨慎。在大规模推广应用前，需对道路融雪盐替代品与添加剂开展全面调研。此外，还需进一步研究盐类添加剂与替代品对两栖类、鱼类等更高营养级生物的影响。